QEMU QMP Reference Manual

Introduction

This document describes all commands currently supported by QMP.

Most of the time their usage is exactly the same as in the user Monitor, this means that any other document which also describe commands (the manpage, QEMU’s manual, etc) can and should be consulted.

QMP has two types of commands: regular and query commands. Regular commands usually change the Virtual Machine’s state someway, while query commands just return information. The sections below are divided accordingly.

It’s important to observe that all communication examples are formatted in a reader-friendly way, so that they’re easier to understand. However, in real protocol usage, they’re emitted as a single line.

Also, the following notation is used to denote data flow:

Example:

-> data issued by the Client
<- Server data response

Please, refer to the QMP specification (docs/interop/qmp-spec.txt) for detailed information on the Server command and response formats.

Stability Considerations

The current QMP command set (described in this file) may be useful for a number of use cases, however it’s limited and several commands have bad defined semantics, specially with regard to command completion.

These problems are going to be solved incrementally in the next QEMU releases and we’re going to establish a deprecation policy for badly defined commands.

If you’re planning to adopt QMP, please observe the following:

  1. The deprecation policy will take effect and be documented soon, please check the documentation of each used command as soon as a new release of QEMU is available
  2. DO NOT rely on anything which is not explicit documented
  3. Errors, in special, are not documented. Applications should NOT check for specific errors classes or data (it’s strongly recommended to only check for the “error” key)

QMP errors

QapiErrorClass (Enum)

QEMU error classes

Values

GenericError
this is used for errors that don’t require a specific error class. This should be the default case for most errors
CommandNotFound
the requested command has not been found
DeviceNotActive
a device has failed to be become active
DeviceNotFound
the requested device has not been found
KVMMissingCap
the requested operation can’t be fulfilled because a required KVM capability is missing

Since

1.2

Common data types

IoOperationType (Enum)

An enumeration of the I/O operation types

Values

read
read operation
write
write operation

Since

2.1

OnOffAuto (Enum)

An enumeration of three options: on, off, and auto

Values

auto
QEMU selects the value between on and off
on
Enabled
off
Disabled

Since

2.2

OnOffSplit (Enum)

An enumeration of three values: on, off, and split

Values

on
Enabled
off
Disabled
split
Mixed

Since

2.6

String (Object)

A fat type wrapping ‘str’, to be embedded in lists.

Members

str: string
Not documented

Since

1.2

StrOrNull (Alternate)

This is a string value or the explicit lack of a string (null pointer in C). Intended for cases when ‘optional absent’ already has a different meaning.

Members

s: string
the string value
n: null
no string value

Since

2.10

OffAutoPCIBAR (Enum)

An enumeration of options for specifying a PCI BAR

Values

off
The specified feature is disabled
auto
The PCI BAR for the feature is automatically selected
bar0
PCI BAR0 is used for the feature
bar1
PCI BAR1 is used for the feature
bar2
PCI BAR2 is used for the feature
bar3
PCI BAR3 is used for the feature
bar4
PCI BAR4 is used for the feature
bar5
PCI BAR5 is used for the feature

Since

2.12

PCIELinkSpeed (Enum)

An enumeration of PCIe link speeds in units of GT/s

Values

2_5
2.5GT/s
5
5.0GT/s
8
8.0GT/s
16
16.0GT/s

Since

4.0

PCIELinkWidth (Enum)

An enumeration of PCIe link width

Values

1
x1
2
x2
4
x4
8
x8
12
x12
16
x16
32
x32

Since

4.0

Socket data types

NetworkAddressFamily (Enum)

The network address family

Values

ipv4
IPV4 family
ipv6
IPV6 family
unix
unix socket
vsock
vsock family (since 2.8)
unknown
otherwise

Since

2.1

InetSocketAddressBase (Object)

Members

host: string
host part of the address
port: string
port part of the address

InetSocketAddress (Object)

Captures a socket address or address range in the Internet namespace.

Members

numeric: boolean (optional)
true if the host/port are guaranteed to be numeric, false if name resolution should be attempted. Defaults to false. (Since 2.9)
to: int (optional)
If present, this is range of possible addresses, with port between port and to.
ipv4: boolean (optional)
whether to accept IPv4 addresses, default try both IPv4 and IPv6
ipv6: boolean (optional)
whether to accept IPv6 addresses, default try both IPv4 and IPv6
keep-alive: boolean (optional)
enable keep-alive when connecting to this socket. Not supported for passive sockets. (Since 4.2)
The members of InetSocketAddressBase

Since

1.3

UnixSocketAddress (Object)

Captures a socket address in the local (“Unix socket”) namespace.

Members

path: string
filesystem path to use

Since

1.3

VsockSocketAddress (Object)

Captures a socket address in the vsock namespace.

Members

cid: string
unique host identifier
port: string
port

Note

string types are used to allow for possible future hostname or service resolution support.

Since

2.8

SocketAddressLegacy (Object)

Captures the address of a socket, which could also be a named file descriptor

Members

type
One of inet, unix, vsock, fd
data: InetSocketAddress when type is "inet"
data: UnixSocketAddress when type is "unix"
data: VsockSocketAddress when type is "vsock"
data: String when type is "fd"

Note

This type is deprecated in favor of SocketAddress. The difference between SocketAddressLegacy and SocketAddress is that the latter is a flat union rather than a simple union. Flat is nicer because it avoids nesting on the wire, i.e. that form has fewer {}.

Since

1.3

SocketAddressType (Enum)

Available SocketAddress types

Values

inet
Internet address
unix
Unix domain socket
vsock
VMCI address
fd
decimal is for file descriptor number, otherwise a file descriptor name. Named file descriptors are permitted in monitor commands, in combination with the ‘getfd’ command. Decimal file descriptors are permitted at startup or other contexts where no monitor context is active.

Since

2.9

SocketAddress (Object)

Captures the address of a socket, which could also be a named file descriptor

Members

type: SocketAddressType
Transport type
The members of InetSocketAddress when type is "inet"
The members of UnixSocketAddress when type is "unix"
The members of VsockSocketAddress when type is "vsock"
The members of String when type is "fd"

Since

2.9

VM run state

RunState (Enum)

An enumeration of VM run states.

Values

debug
QEMU is running on a debugger
finish-migrate
guest is paused to finish the migration process
inmigrate
guest is paused waiting for an incoming migration. Note that this state does not tell whether the machine will start at the end of the migration. This depends on the command-line -S option and any invocation of ‘stop’ or ‘cont’ that has happened since QEMU was started.
internal-error
An internal error that prevents further guest execution has occurred
io-error
the last IOP has failed and the device is configured to pause on I/O errors
paused
guest has been paused via the ‘stop’ command
postmigrate
guest is paused following a successful ‘migrate’
prelaunch
QEMU was started with -S and guest has not started
restore-vm
guest is paused to restore VM state
running
guest is actively running
save-vm
guest is paused to save the VM state
shutdown
guest is shut down (and -no-shutdown is in use)
suspended
guest is suspended (ACPI S3)
watchdog
the watchdog action is configured to pause and has been triggered
guest-panicked
guest has been panicked as a result of guest OS panic
colo
guest is paused to save/restore VM state under colo checkpoint, VM can not get into this state unless colo capability is enabled for migration. (since 2.8)
preconfig
QEMU is paused before board specific init callback is executed. The state is reachable only if the –preconfig CLI option is used. (Since 3.0)

ShutdownCause (Enum)

An enumeration of reasons for a Shutdown.

Values

none
No shutdown request pending
host-error
An error prevents further use of guest
host-qmp-quit
Reaction to the QMP command ‘quit’
host-qmp-system-reset
Reaction to the QMP command ‘system_reset’
host-signal
Reaction to a signal, such as SIGINT
host-ui
Reaction to a UI event, like window close
guest-shutdown
Guest shutdown/suspend request, via ACPI or other hardware-specific means
guest-reset
Guest reset request, and command line turns that into a shutdown
guest-panic
Guest panicked, and command line turns that into a shutdown
subsystem-reset
Partial guest reset that does not trigger QMP events and ignores –no-reboot. This is useful for sanitizing hypercalls on s390 that are used during kexec/kdump/boot

StatusInfo (Object)

Information about VCPU run state

Members

running: boolean
true if all VCPUs are runnable, false if not runnable
singlestep: boolean
true if VCPUs are in single-step mode
status: RunState
the virtual machine RunState

Since

0.14.0

Notes

singlestep is enabled through the GDB stub

query-status (Command)

Query the run status of all VCPUs

Returns

StatusInfo reflecting all VCPUs

Since

0.14.0

Example

-> { "execute": "query-status" }
<- { "return": { "running": true,
                 "singlestep": false,
                 "status": "running" } }

SHUTDOWN (Event)

Emitted when the virtual machine has shut down, indicating that qemu is about to exit.

Arguments

guest: boolean
If true, the shutdown was triggered by a guest request (such as a guest-initiated ACPI shutdown request or other hardware-specific action) rather than a host request (such as sending qemu a SIGINT). (since 2.10)
reason: ShutdownCause
The ShutdownCause which resulted in the SHUTDOWN. (since 4.0)

Note

If the command-line option “-no-shutdown” has been specified, qemu will not exit, and a STOP event will eventually follow the SHUTDOWN event

Since

0.12.0

Example

<- { "event": "SHUTDOWN", "data": { "guest": true },
     "timestamp": { "seconds": 1267040730, "microseconds": 682951 } }

POWERDOWN (Event)

Emitted when the virtual machine is powered down through the power control system, such as via ACPI.

Since

0.12.0

Example

<- { "event": "POWERDOWN",
     "timestamp": { "seconds": 1267040730, "microseconds": 682951 } }

RESET (Event)

Emitted when the virtual machine is reset

Arguments

guest: boolean
If true, the reset was triggered by a guest request (such as a guest-initiated ACPI reboot request or other hardware-specific action) rather than a host request (such as the QMP command system_reset). (since 2.10)
reason: ShutdownCause
The ShutdownCause of the RESET. (since 4.0)

Since

0.12.0

Example

<- { "event": "RESET", "data": { "guest": false },
     "timestamp": { "seconds": 1267041653, "microseconds": 9518 } }

STOP (Event)

Emitted when the virtual machine is stopped

Since

0.12.0

Example

<- { "event": "STOP",
     "timestamp": { "seconds": 1267041730, "microseconds": 281295 } }

RESUME (Event)

Emitted when the virtual machine resumes execution

Since

0.12.0

Example

<- { "event": "RESUME",
     "timestamp": { "seconds": 1271770767, "microseconds": 582542 } }

SUSPEND (Event)

Emitted when guest enters a hardware suspension state, for example, S3 state, which is sometimes called standby state

Since

1.1

Example

<- { "event": "SUSPEND",
     "timestamp": { "seconds": 1344456160, "microseconds": 309119 } }

SUSPEND_DISK (Event)

Emitted when guest enters a hardware suspension state with data saved on disk, for example, S4 state, which is sometimes called hibernate state

Note

QEMU shuts down (similar to event SHUTDOWN) when entering this state

Since

1.2

Example

<-   { "event": "SUSPEND_DISK",
       "timestamp": { "seconds": 1344456160, "microseconds": 309119 } }

WAKEUP (Event)

Emitted when the guest has woken up from suspend state and is running

Since

1.1

Example

<- { "event": "WAKEUP",
     "timestamp": { "seconds": 1344522075, "microseconds": 745528 } }

WATCHDOG (Event)

Emitted when the watchdog device’s timer is expired

Arguments

action: WatchdogAction
action that has been taken

Note

If action is “reset”, “shutdown”, or “pause” the WATCHDOG event is followed respectively by the RESET, SHUTDOWN, or STOP events

Note

This event is rate-limited.

Since

0.13.0

Example

<- { "event": "WATCHDOG",
     "data": { "action": "reset" },
     "timestamp": { "seconds": 1267061043, "microseconds": 959568 } }

WatchdogAction (Enum)

An enumeration of the actions taken when the watchdog device’s timer is expired

Values

reset
system resets
shutdown
system shutdown, note that it is similar to powerdown, which tries to set to system status and notify guest
poweroff
system poweroff, the emulator program exits
pause
system pauses, similar to stop
debug
system enters debug state
none
nothing is done
inject-nmi
a non-maskable interrupt is injected into the first VCPU (all VCPUS on x86) (since 2.4)

Since

2.1

watchdog-set-action (Command)

Set watchdog action

Arguments

action: WatchdogAction
Not documented

Since

2.11

GUEST_PANICKED (Event)

Emitted when guest OS panic is detected

Arguments

action: GuestPanicAction
action that has been taken, currently always “pause”
info: GuestPanicInformation (optional)
information about a panic (since 2.9)

Since

1.5

Example

<- { "event": "GUEST_PANICKED",
     "data": { "action": "pause" } }

GUEST_CRASHLOADED (Event)

Emitted when guest OS crash loaded is detected

Arguments

action: GuestPanicAction
action that has been taken, currently always “run”
info: GuestPanicInformation (optional)
information about a panic

Since

5.0

Example

<- { "event": "GUEST_CRASHLOADED",
     "data": { "action": "run" } }

GuestPanicAction (Enum)

An enumeration of the actions taken when guest OS panic is detected

Values

pause
system pauses
poweroff
Not documented
run
Not documented

Since

2.1 (poweroff since 2.8, run since 5.0)

GuestPanicInformationType (Enum)

An enumeration of the guest panic information types

Values

hyper-v
hyper-v guest panic information type
s390
s390 guest panic information type (Since: 2.12)

Since

2.9

GuestPanicInformation (Object)

Information about a guest panic

Members

type: GuestPanicInformationType
Crash type that defines the hypervisor specific information
The members of GuestPanicInformationHyperV when type is "hyper-v"
The members of GuestPanicInformationS390 when type is "s390"

Since

2.9

GuestPanicInformationHyperV (Object)

Hyper-V specific guest panic information (HV crash MSRs)

Members

arg1: int
Not documented
arg2: int
Not documented
arg3: int
Not documented
arg4: int
Not documented
arg5: int
Not documented

Since

2.9

S390CrashReason (Enum)

Reason why the CPU is in a crashed state.

Values

unknown
no crash reason was set
disabled-wait
the CPU has entered a disabled wait state
extint-loop
clock comparator or cpu timer interrupt with new PSW enabled for external interrupts
pgmint-loop
program interrupt with BAD new PSW
opint-loop
operation exception interrupt with invalid code at the program interrupt new PSW

Since

2.12

GuestPanicInformationS390 (Object)

S390 specific guest panic information (PSW)

Members

core: int
core id of the CPU that crashed
psw-mask: int
control fields of guest PSW
psw-addr: int
guest instruction address
reason: S390CrashReason
guest crash reason

Since

2.12

Cryptography

QCryptoTLSCredsEndpoint (Enum)

The type of network endpoint that will be using the credentials. Most types of credential require different setup / structures depending on whether they will be used in a server versus a client.

Values

client
the network endpoint is acting as the client
server
the network endpoint is acting as the server

Since

2.5

QCryptoSecretFormat (Enum)

The data format that the secret is provided in

Values

raw
raw bytes. When encoded in JSON only valid UTF-8 sequences can be used
base64
arbitrary base64 encoded binary data

Since

2.6

QCryptoHashAlgorithm (Enum)

The supported algorithms for computing content digests

Values

md5
MD5. Should not be used in any new code, legacy compat only
sha1
SHA-1. Should not be used in any new code, legacy compat only
sha224
SHA-224. (since 2.7)
sha256
SHA-256. Current recommended strong hash.
sha384
SHA-384. (since 2.7)
sha512
SHA-512. (since 2.7)
ripemd160
RIPEMD-160. (since 2.7)

Since

2.6

QCryptoCipherAlgorithm (Enum)

The supported algorithms for content encryption ciphers

Values

aes-128
AES with 128 bit / 16 byte keys
aes-192
AES with 192 bit / 24 byte keys
aes-256
AES with 256 bit / 32 byte keys
des-rfb
RFB specific variant of single DES. Do not use except in VNC.
3des
3DES(EDE) with 192 bit / 24 byte keys (since 2.9)
cast5-128
Cast5 with 128 bit / 16 byte keys
serpent-128
Serpent with 128 bit / 16 byte keys
serpent-192
Serpent with 192 bit / 24 byte keys
serpent-256
Serpent with 256 bit / 32 byte keys
twofish-128
Twofish with 128 bit / 16 byte keys
twofish-192
Twofish with 192 bit / 24 byte keys
twofish-256
Twofish with 256 bit / 32 byte keys

Since

2.6

QCryptoCipherMode (Enum)

The supported modes for content encryption ciphers

Values

ecb
Electronic Code Book
cbc
Cipher Block Chaining
xts
XEX with tweaked code book and ciphertext stealing
ctr
Counter (Since 2.8)

Since

2.6

QCryptoIVGenAlgorithm (Enum)

The supported algorithms for generating initialization vectors for full disk encryption. The ‘plain’ generator should not be used for disks with sector numbers larger than 2^32, except where compatibility with pre-existing Linux dm-crypt volumes is required.

Values

plain
64-bit sector number truncated to 32-bits
plain64
64-bit sector number
essiv
64-bit sector number encrypted with a hash of the encryption key

Since

2.6

QCryptoBlockFormat (Enum)

The supported full disk encryption formats

Values

qcow
QCow/QCow2 built-in AES-CBC encryption. Use only for liberating data from old images.
luks
LUKS encryption format. Recommended for new images

Since

2.6

QCryptoBlockOptionsBase (Object)

The common options that apply to all full disk encryption formats

Members

format: QCryptoBlockFormat
the encryption format

Since

2.6

QCryptoBlockOptionsQCow (Object)

The options that apply to QCow/QCow2 AES-CBC encryption format

Members

key-secret: string (optional)
the ID of a QCryptoSecret object providing the decryption key. Mandatory except when probing image for metadata only.

Since

2.6

QCryptoBlockOptionsLUKS (Object)

The options that apply to LUKS encryption format

Members

key-secret: string (optional)
the ID of a QCryptoSecret object providing the decryption key. Mandatory except when probing image for metadata only.

Since

2.6

QCryptoBlockCreateOptionsLUKS (Object)

The options that apply to LUKS encryption format initialization

Members

cipher-alg: QCryptoCipherAlgorithm (optional)
the cipher algorithm for data encryption Currently defaults to ‘aes-256’.
cipher-mode: QCryptoCipherMode (optional)
the cipher mode for data encryption Currently defaults to ‘xts’
ivgen-alg: QCryptoIVGenAlgorithm (optional)
the initialization vector generator Currently defaults to ‘plain64’
ivgen-hash-alg: QCryptoHashAlgorithm (optional)
the initialization vector generator hash Currently defaults to ‘sha256’
hash-alg: QCryptoHashAlgorithm (optional)
the master key hash algorithm Currently defaults to ‘sha256’
iter-time: int (optional)
number of milliseconds to spend in PBKDF passphrase processing. Currently defaults to 2000. (since 2.8)
The members of QCryptoBlockOptionsLUKS

Since

2.6

QCryptoBlockOpenOptions (Object)

The options that are available for all encryption formats when opening an existing volume

Members

The members of QCryptoBlockOptionsBase
The members of QCryptoBlockOptionsQCow when format is "qcow"
The members of QCryptoBlockOptionsLUKS when format is "luks"

Since

2.6

QCryptoBlockCreateOptions (Object)

The options that are available for all encryption formats when initializing a new volume

Members

The members of QCryptoBlockOptionsBase
The members of QCryptoBlockOptionsQCow when format is "qcow"
The members of QCryptoBlockCreateOptionsLUKS when format is "luks"

Since

2.6

QCryptoBlockInfoBase (Object)

The common information that applies to all full disk encryption formats

Members

format: QCryptoBlockFormat
the encryption format

Since

2.7

QCryptoBlockInfoLUKSSlot (Object)

Information about the LUKS block encryption key slot options

Members

active: boolean
whether the key slot is currently in use
key-offset: int
offset to the key material in bytes
iters: int (optional)
number of PBKDF2 iterations for key material
stripes: int (optional)
number of stripes for splitting key material

Since

2.7

QCryptoBlockInfoLUKS (Object)

Information about the LUKS block encryption options

Members

cipher-alg: QCryptoCipherAlgorithm
the cipher algorithm for data encryption
cipher-mode: QCryptoCipherMode
the cipher mode for data encryption
ivgen-alg: QCryptoIVGenAlgorithm
the initialization vector generator
ivgen-hash-alg: QCryptoHashAlgorithm (optional)
the initialization vector generator hash
hash-alg: QCryptoHashAlgorithm
the master key hash algorithm
payload-offset: int
offset to the payload data in bytes
master-key-iters: int
number of PBKDF2 iterations for key material
uuid: string
unique identifier for the volume
slots: array of QCryptoBlockInfoLUKSSlot
information about each key slot

Since

2.7

QCryptoBlockInfo (Object)

Information about the block encryption options

Members

The members of QCryptoBlockInfoBase
The members of QCryptoBlockInfoLUKS when format is "luks"

Since

2.7

Block devices

Block core (VM unrelated)

Background jobs

JobType (Enum)

Type of a background job.

Values
commit
block commit job type, see “block-commit”
stream
block stream job type, see “block-stream”
mirror
drive mirror job type, see “drive-mirror”
backup
drive backup job type, see “drive-backup”
create
image creation job type, see “blockdev-create” (since 3.0)
Since

1.7

JobStatus (Enum)

Indicates the present state of a given job in its lifetime.

Values
undefined
Erroneous, default state. Should not ever be visible.
created
The job has been created, but not yet started.
running
The job is currently running.
paused
The job is running, but paused. The pause may be requested by either the QMP user or by internal processes.
ready
The job is running, but is ready for the user to signal completion. This is used for long-running jobs like mirror that are designed to run indefinitely.
standby
The job is ready, but paused. This is nearly identical to paused. The job may return to ready or otherwise be canceled.
waiting
The job is waiting for other jobs in the transaction to converge to the waiting state. This status will likely not be visible for the last job in a transaction.
pending
The job has finished its work, but has finalization steps that it needs to make prior to completing. These changes will require manual intervention via job-finalize if auto-finalize was set to false. These pending changes may still fail.
aborting
The job is in the process of being aborted, and will finish with an error. The job will afterwards report that it is concluded. This status may not be visible to the management process.
concluded
The job has finished all work. If auto-dismiss was set to false, the job will remain in the query list until it is dismissed via job-dismiss.
null
The job is in the process of being dismantled. This state should not ever be visible externally.
Since

2.12

JobVerb (Enum)

Represents command verbs that can be applied to a job.

Values
cancel
see job-cancel
pause
see job-pause
resume
see job-resume
set-speed
see block-job-set-speed
complete
see job-complete
dismiss
see job-dismiss
finalize
see job-finalize
Since

2.12

JOB_STATUS_CHANGE (Event)

Emitted when a job transitions to a different status.

Arguments
id: string
The job identifier
status: JobStatus
The new job status
Since

3.0

job-pause (Command)

Pause an active job.

This command returns immediately after marking the active job for pausing. Pausing an already paused job is an error.

The job will pause as soon as possible, which means transitioning into the PAUSED state if it was RUNNING, or into STANDBY if it was READY. The corresponding JOB_STATUS_CHANGE event will be emitted.

Cancelling a paused job automatically resumes it.

Arguments
id: string
The job identifier.
Since

3.0

job-resume (Command)

Resume a paused job.

This command returns immediately after resuming a paused job. Resuming an already running job is an error.

id : The job identifier.

Arguments
id: string
Not documented
Since

3.0

job-cancel (Command)

Instruct an active background job to cancel at the next opportunity. This command returns immediately after marking the active job for cancellation.

The job will cancel as soon as possible and then emit a JOB_STATUS_CHANGE event. Usually, the status will change to ABORTING, but it is possible that a job successfully completes (e.g. because it was almost done and there was no opportunity to cancel earlier than completing the job) and transitions to PENDING instead.

Arguments
id: string
The job identifier.
Since

3.0

job-complete (Command)

Manually trigger completion of an active job in the READY state.

Arguments
id: string
The job identifier.
Since

3.0

job-dismiss (Command)

Deletes a job that is in the CONCLUDED state. This command only needs to be run explicitly for jobs that don’t have automatic dismiss enabled.

This command will refuse to operate on any job that has not yet reached its terminal state, JOB_STATUS_CONCLUDED. For jobs that make use of JOB_READY event, job-cancel or job-complete will still need to be used as appropriate.

Arguments
id: string
The job identifier.
Since

3.0

job-finalize (Command)

Instructs all jobs in a transaction (or a single job if it is not part of any transaction) to finalize any graph changes and do any necessary cleanup. This command requires that all involved jobs are in the PENDING state.

For jobs in a transaction, instructing one job to finalize will force ALL jobs in the transaction to finalize, so it is only necessary to instruct a single member job to finalize.

Arguments
id: string
The identifier of any job in the transaction, or of a job that is not part of any transaction.
Since

3.0

JobInfo (Object)

Information about a job.

Members
id: string
The job identifier
type: JobType
The kind of job that is being performed
status: JobStatus
Current job state/status
current-progress: int
Progress made until now. The unit is arbitrary and the value can only meaningfully be used for the ratio of current-progress to total-progress. The value is monotonically increasing.
total-progress: int
Estimated current-progress value at the completion of the job. This value can arbitrarily change while the job is running, in both directions.
error: string (optional)

If this field is present, the job failed; if it is still missing in the CONCLUDED state, this indicates successful completion.

The value is a human-readable error message to describe the reason for the job failure. It should not be parsed by applications.

Since

3.0

query-jobs (Command)

Return information about jobs.

Returns

a list with a JobInfo for each active job

Since

3.0

SnapshotInfo (Object)

Members
id: string
unique snapshot id
name: string
user chosen name
vm-state-size: int
size of the VM state
date-sec: int
UTC date of the snapshot in seconds
date-nsec: int
fractional part in nano seconds to be used with date-sec
vm-clock-sec: int
VM clock relative to boot in seconds
vm-clock-nsec: int
fractional part in nano seconds to be used with vm-clock-sec
Since

1.3

ImageInfoSpecificQCow2EncryptionBase (Object)

Members
format: BlockdevQcow2EncryptionFormat
The encryption format
Since

2.10

ImageInfoSpecificQCow2Encryption (Object)

Members
The members of ImageInfoSpecificQCow2EncryptionBase
The members of QCryptoBlockInfoLUKS when format is "luks"
Since

2.10

ImageInfoSpecificQCow2 (Object)

Members
compat: string
compatibility level
data-file: string (optional)
the filename of the external data file that is stored in the image and used as a default for opening the image (since: 4.0)
data-file-raw: boolean (optional)
True if the external data file must stay valid as a standalone (read-only) raw image without looking at qcow2 metadata (since: 4.0)
lazy-refcounts: boolean (optional)
on or off; only valid for compat >= 1.1
corrupt: boolean (optional)
true if the image has been marked corrupt; only valid for compat >= 1.1 (since 2.2)
refcount-bits: int
width of a refcount entry in bits (since 2.3)
encrypt: ImageInfoSpecificQCow2Encryption (optional)
details about encryption parameters; only set if image is encrypted (since 2.10)
bitmaps: array of Qcow2BitmapInfo (optional)
A list of qcow2 bitmap details (since 4.0)
Since

1.7

ImageInfoSpecificVmdk (Object)

Members
create-type: string
The create type of VMDK image
cid: int
Content id of image
parent-cid: int
Parent VMDK image’s cid
extents: array of ImageInfo
List of extent files
Since

1.7

ImageInfoSpecific (Object)

A discriminated record of image format specific information structures.

Members
type
One of qcow2, vmdk, luks
data: ImageInfoSpecificQCow2 when type is "qcow2"
data: ImageInfoSpecificVmdk when type is "vmdk"
data: QCryptoBlockInfoLUKS when type is "luks"
Since

1.7

ImageInfo (Object)

Information about a QEMU image file

Members
filename: string
name of the image file
format: string
format of the image file
virtual-size: int
maximum capacity in bytes of the image
actual-size: int (optional)
actual size on disk in bytes of the image
dirty-flag: boolean (optional)
true if image is not cleanly closed
cluster-size: int (optional)
size of a cluster in bytes
encrypted: boolean (optional)
true if the image is encrypted
compressed: boolean (optional)
true if the image is compressed (Since 1.7)
backing-filename: string (optional)
name of the backing file
full-backing-filename: string (optional)
full path of the backing file
backing-filename-format: string (optional)
the format of the backing file
snapshots: array of SnapshotInfo (optional)
list of VM snapshots
backing-image: ImageInfo (optional)
info of the backing image (since 1.6)
format-specific: ImageInfoSpecific (optional)
structure supplying additional format-specific information (since 1.7)
Since

1.3

ImageCheck (Object)

Information about a QEMU image file check

Members
filename: string
name of the image file checked
format: string
format of the image file checked
check-errors: int
number of unexpected errors occurred during check
image-end-offset: int (optional)
offset (in bytes) where the image ends, this field is present if the driver for the image format supports it
corruptions: int (optional)
number of corruptions found during the check if any
leaks: int (optional)
number of leaks found during the check if any
corruptions-fixed: int (optional)
number of corruptions fixed during the check if any
leaks-fixed: int (optional)
number of leaks fixed during the check if any
total-clusters: int (optional)
total number of clusters, this field is present if the driver for the image format supports it
allocated-clusters: int (optional)
total number of allocated clusters, this field is present if the driver for the image format supports it
fragmented-clusters: int (optional)
total number of fragmented clusters, this field is present if the driver for the image format supports it
compressed-clusters: int (optional)
total number of compressed clusters, this field is present if the driver for the image format supports it
Since

1.4

MapEntry (Object)

Mapping information from a virtual block range to a host file range

Members
start: int
the start byte of the mapped virtual range
length: int
the number of bytes of the mapped virtual range
data: boolean
whether the mapped range has data
zero: boolean
whether the virtual blocks are zeroed
depth: int
the depth of the mapping
offset: int (optional)
the offset in file that the virtual sectors are mapped to
filename: string (optional)
filename that is referred to by offset
Since

2.6

BlockdevCacheInfo (Object)

Cache mode information for a block device

Members
writeback: boolean
true if writeback mode is enabled
direct: boolean
true if the host page cache is bypassed (O_DIRECT)
no-flush: boolean
true if flush requests are ignored for the device
Since

2.3

BlockDeviceInfo (Object)

Information about the backing device for a block device.

Members
file: string
the filename of the backing device
node-name: string (optional)
the name of the block driver node (Since 2.0)
ro: boolean
true if the backing device was open read-only
drv: string
the name of the block format used to open the backing device. As of 0.14.0 this can be: ‘blkdebug’, ‘bochs’, ‘cloop’, ‘cow’, ‘dmg’, ‘file’, ‘file’, ‘ftp’, ‘ftps’, ‘host_cdrom’, ‘host_device’, ‘http’, ‘https’, ‘luks’, ‘nbd’, ‘parallels’, ‘qcow’, ‘qcow2’, ‘raw’, ‘vdi’, ‘vmdk’, ‘vpc’, ‘vvfat’ 2.2: ‘archipelago’ added, ‘cow’ dropped 2.3: ‘host_floppy’ deprecated 2.5: ‘host_floppy’ dropped 2.6: ‘luks’ added 2.8: ‘replication’ added, ‘tftp’ dropped 2.9: ‘archipelago’ dropped
backing_file: string (optional)
the name of the backing file (for copy-on-write)
backing_file_depth: int
number of files in the backing file chain (since: 1.2)
encrypted: boolean
true if the backing device is encrypted
encryption_key_missing: boolean
Deprecated; always false
detect_zeroes: BlockdevDetectZeroesOptions
detect and optimize zero writes (Since 2.1)
bps: int
total throughput limit in bytes per second is specified
bps_rd: int
read throughput limit in bytes per second is specified
bps_wr: int
write throughput limit in bytes per second is specified
iops: int
total I/O operations per second is specified
iops_rd: int
read I/O operations per second is specified
iops_wr: int
write I/O operations per second is specified
image: ImageInfo
the info of image used (since: 1.6)
bps_max: int (optional)
total throughput limit during bursts,
in bytes (Since 1.7)
bps_rd_max: int (optional)
read throughput limit during bursts,
in bytes (Since 1.7)
bps_wr_max: int (optional)
write throughput limit during bursts,
in bytes (Since 1.7)
iops_max: int (optional)
total I/O operations per second during bursts,
in bytes (Since 1.7)
iops_rd_max: int (optional)
read I/O operations per second during bursts,
in bytes (Since 1.7)
iops_wr_max: int (optional)
write I/O operations per second during bursts,
in bytes (Since 1.7)
bps_max_length: int (optional)
maximum length of the bps_max burst
period, in seconds. (Since 2.6)
bps_rd_max_length: int (optional)
maximum length of the bps_rd_max
burst period, in seconds. (Since 2.6)
bps_wr_max_length: int (optional)
maximum length of the bps_wr_max
burst period, in seconds. (Since 2.6)
iops_max_length: int (optional)
maximum length of the iops burst
period, in seconds. (Since 2.6)
iops_rd_max_length: int (optional)
maximum length of the iops_rd_max
burst period, in seconds. (Since 2.6)
iops_wr_max_length: int (optional)
maximum length of the iops_wr_max
burst period, in seconds. (Since 2.6)
iops_size: int (optional)
an I/O size in bytes (Since 1.7)
group: string (optional)
throttle group name (Since 2.4)
cache: BlockdevCacheInfo
the cache mode used for the block device (since: 2.3)
write_threshold: int
configured write threshold for the device. 0 if disabled. (Since 2.3)
dirty-bitmaps: array of BlockDirtyInfo (optional)
dirty bitmaps information (only present if node has one or more dirty bitmaps) (Since 4.2)
Since

0.14.0

BlockDeviceIoStatus (Enum)

An enumeration of block device I/O status.

Values
ok
The last I/O operation has succeeded
failed
The last I/O operation has failed
nospace
The last I/O operation has failed due to a no-space condition
Since

1.0

BlockDeviceMapEntry (Object)

Entry in the metadata map of the device (returned by “qemu-img map”)

Members
start: int
Offset in the image of the first byte described by this entry (in bytes)
length: int
Length of the range described by this entry (in bytes)
depth: int
Number of layers (0 = top image, 1 = top image’s backing file, etc.) before reaching one for which the range is allocated. The value is in the range 0 to the depth of the image chain - 1.
zero: boolean
the sectors in this range read as zeros
data: boolean
reading the image will actually read data from a file (in particular, if offset is present this means that the sectors are not simply preallocated, but contain actual data in raw format)
offset: int (optional)
if present, the image file stores the data for this range in raw format at the given offset.
Since

1.7

DirtyBitmapStatus (Enum)

An enumeration of possible states that a dirty bitmap can report to the user.

Values
frozen
The bitmap is currently in-use by some operation and is immutable. If the bitmap was active prior to the operation, new writes by the guest are being recorded in a temporary buffer, and will not be lost. Generally, bitmaps are cleared on successful use in an operation and the temporary buffer is committed into the bitmap. On failure, the temporary buffer is merged back into the bitmap without first clearing it. Please refer to the documentation for each bitmap-using operation, See also blockdev-backup, drive-backup.
disabled
The bitmap is not currently recording new writes by the guest. This is requested explicitly via block-dirty-bitmap-disable. It can still be cleared, deleted, or used for backup operations.
active
The bitmap is actively monitoring for new writes, and can be cleared, deleted, or used for backup operations.
locked
The bitmap is currently in-use by some operation and is immutable. If the bitmap was active prior to the operation, it is still recording new writes. If the bitmap was disabled, it is not recording new writes. (Since 2.12)
inconsistent
This is a persistent dirty bitmap that was marked in-use on disk, and is unusable by QEMU. It can only be deleted. Please rely on the inconsistent field in BlockDirtyInfo instead, as the status field is deprecated. (Since 4.0)
Since

2.4

BlockDirtyInfo (Object)

Block dirty bitmap information.

Members
name: string (optional)
the name of the dirty bitmap (Since 2.4)
count: int
number of dirty bytes according to the dirty bitmap
granularity: int
granularity of the dirty bitmap in bytes (since 1.4)
status: DirtyBitmapStatus
Deprecated in favor of recording and locked. (since 2.4)
recording: boolean
true if the bitmap is recording new writes from the guest. Replaces active and disabled statuses. (since 4.0)
busy: boolean
true if the bitmap is in-use by some operation (NBD or jobs) and cannot be modified via QMP or used by another operation. Replaces locked and frozen statuses. (since 4.0)
persistent: boolean
true if the bitmap was stored on disk, is scheduled to be stored on disk, or both. (since 4.0)
inconsistent: boolean (optional)
true if this is a persistent bitmap that was improperly stored. Implies persistent to be true; recording and busy to be false. This bitmap cannot be used. To remove it, use block-dirty-bitmap-remove. (Since 4.0)
Since

1.3

Qcow2BitmapInfoFlags (Enum)

An enumeration of flags that a bitmap can report to the user.

Values
in-use
This flag is set by any process actively modifying the qcow2 file, and cleared when the updated bitmap is flushed to the qcow2 image. The presence of this flag in an offline image means that the bitmap was not saved correctly after its last usage, and may contain inconsistent data.
auto
The bitmap must reflect all changes of the virtual disk by any application that would write to this qcow2 file.
Since

4.0

Qcow2BitmapInfo (Object)

Qcow2 bitmap information.

Members
name: string
the name of the bitmap
granularity: int
granularity of the bitmap in bytes
flags: array of Qcow2BitmapInfoFlags
flags of the bitmap
Since

4.0

BlockLatencyHistogramInfo (Object)

Block latency histogram.

Members
boundaries: array of int
list of interval boundary values in nanoseconds, all greater than zero and in ascending order. For example, the list [10, 50, 100] produces the following histogram intervals: [0, 10), [10, 50), [50, 100), [100, +inf).
bins: array of int
list of io request counts corresponding to histogram intervals. len(bins) = len(boundaries) + 1 For the example above, bins may be something like [3, 1, 5, 2], and corresponding histogram looks like:
5|           *
4|           *
3| *         *
2| *         *    *
1| *    *    *    *
 +------------------
     10   50   100
Since

4.0

block-latency-histogram-set (Command)

Manage read, write and flush latency histograms for the device.

If only id parameter is specified, remove all present latency histograms for the device. Otherwise, add/reset some of (or all) latency histograms.

Arguments
id: string
The name or QOM path of the guest device.
boundaries: array of int (optional)
list of interval boundary values (see description in BlockLatencyHistogramInfo definition). If specified, all latency histograms are removed, and empty ones created for all io types with intervals corresponding to boundaries (except for io types, for which specific boundaries are set through the following parameters).
boundaries-read: array of int (optional)
list of interval boundary values for read latency histogram. If specified, old read latency histogram is removed, and empty one created with intervals corresponding to boundaries-read. The parameter has higher priority then boundaries.
boundaries-write: array of int (optional)
list of interval boundary values for write latency histogram.
boundaries-flush: array of int (optional)
list of interval boundary values for flush latency histogram.
Returns

error if device is not found or any boundary arrays are invalid.

Since

4.0

Example
set new histograms for all io types with intervals
[0, 10), [10, 50), [50, 100), [100, +inf):

-> { "execute": "block-latency-histogram-set",
     "arguments": { "id": "drive0",
                    "boundaries": [10, 50, 100] } }
<- { "return": {} }
Example
set new histogram only for write, other histograms will remain
not changed (or not created):

-> { "execute": "block-latency-histogram-set",
     "arguments": { "id": "drive0",
                    "boundaries-write": [10, 50, 100] } }
<- { "return": {} }
Example
set new histograms with the following intervals:
  read, flush: [0, 10), [10, 50), [50, 100), [100, +inf)
  write: [0, 1000), [1000, 5000), [5000, +inf)

-> { "execute": "block-latency-histogram-set",
     "arguments": { "id": "drive0",
                    "boundaries": [10, 50, 100],
                    "boundaries-write": [1000, 5000] } }
<- { "return": {} }
Example
remove all latency histograms:

-> { "execute": "block-latency-histogram-set",
     "arguments": { "id": "drive0" } }
<- { "return": {} }

BlockInfo (Object)

Block device information. This structure describes a virtual device and the backing device associated with it.

Members
device: string
The device name associated with the virtual device.
qdev: string (optional)
The qdev ID, or if no ID is assigned, the QOM path of the block device. (since 2.10)
type: string
This field is returned only for compatibility reasons, it should not be used (always returns ‘unknown’)
removable: boolean
True if the device supports removable media.
locked: boolean
True if the guest has locked this device from having its media removed
tray_open: boolean (optional)
True if the device’s tray is open (only present if it has a tray)
dirty-bitmaps: array of BlockDirtyInfo (optional)
dirty bitmaps information (only present if the driver has one or more dirty bitmaps) (Since 2.0) Deprecated in 4.2; see BlockDeviceInfo instead.
io-status: BlockDeviceIoStatus (optional)
BlockDeviceIoStatus. Only present if the device supports it and the VM is configured to stop on errors (supported device models: virtio-blk, IDE, SCSI except scsi-generic)
inserted: BlockDeviceInfo (optional)
BlockDeviceInfo describing the device if media is present
Since

0.14.0

BlockMeasureInfo (Object)

Image file size calculation information. This structure describes the size requirements for creating a new image file.

The size requirements depend on the new image file format. File size always equals virtual disk size for the ‘raw’ format, even for sparse POSIX files. Compact formats such as ‘qcow2’ represent unallocated and zero regions efficiently so file size may be smaller than virtual disk size.

The values are upper bounds that are guaranteed to fit the new image file. Subsequent modification, such as internal snapshot or bitmap creation, may require additional space and is not covered here.

Members
required: int
Size required for a new image file, in bytes.
fully-allocated: int
Image file size, in bytes, once data has been written to all sectors.
Since

2.10

query-block (Command)

Get a list of BlockInfo for all virtual block devices.

Returns

a list of BlockInfo describing each virtual block device. Filter nodes that were created implicitly are skipped over.

Since

0.14.0

Example
-> { "execute": "query-block" }
<- {
      "return":[
         {
            "io-status": "ok",
            "device":"ide0-hd0",
            "locked":false,
            "removable":false,
            "inserted":{
               "ro":false,
               "drv":"qcow2",
               "encrypted":false,
               "file":"disks/test.qcow2",
               "backing_file_depth":1,
               "bps":1000000,
               "bps_rd":0,
               "bps_wr":0,
               "iops":1000000,
               "iops_rd":0,
               "iops_wr":0,
               "bps_max": 8000000,
               "bps_rd_max": 0,
               "bps_wr_max": 0,
               "iops_max": 0,
               "iops_rd_max": 0,
               "iops_wr_max": 0,
               "iops_size": 0,
               "detect_zeroes": "on",
               "write_threshold": 0,
               "image":{
                  "filename":"disks/test.qcow2",
                  "format":"qcow2",
                  "virtual-size":2048000,
                  "backing_file":"base.qcow2",
                  "full-backing-filename":"disks/base.qcow2",
                  "backing-filename-format":"qcow2",
                  "snapshots":[
                     {
                        "id": "1",
                        "name": "snapshot1",
                        "vm-state-size": 0,
                        "date-sec": 10000200,
                        "date-nsec": 12,
                        "vm-clock-sec": 206,
                        "vm-clock-nsec": 30
                     }
                  ],
                  "backing-image":{
                      "filename":"disks/base.qcow2",
                      "format":"qcow2",
                      "virtual-size":2048000
                  }
               }
            },
            "qdev": "ide_disk",
            "type":"unknown"
         },
         {
            "io-status": "ok",
            "device":"ide1-cd0",
            "locked":false,
            "removable":true,
            "qdev": "/machine/unattached/device[23]",
            "tray_open": false,
            "type":"unknown"
         },
         {
            "device":"floppy0",
            "locked":false,
            "removable":true,
            "qdev": "/machine/unattached/device[20]",
            "type":"unknown"
         },
         {
            "device":"sd0",
            "locked":false,
            "removable":true,
            "type":"unknown"
         }
      ]
   }

BlockDeviceTimedStats (Object)

Statistics of a block device during a given interval of time.

Members
interval_length: int
Interval used for calculating the statistics, in seconds.
min_rd_latency_ns: int
Minimum latency of read operations in the defined interval, in nanoseconds.
min_wr_latency_ns: int
Minimum latency of write operations in the defined interval, in nanoseconds.
min_flush_latency_ns: int
Minimum latency of flush operations in the defined interval, in nanoseconds.
max_rd_latency_ns: int
Maximum latency of read operations in the defined interval, in nanoseconds.
max_wr_latency_ns: int
Maximum latency of write operations in the defined interval, in nanoseconds.
max_flush_latency_ns: int
Maximum latency of flush operations in the defined interval, in nanoseconds.
avg_rd_latency_ns: int
Average latency of read operations in the defined interval, in nanoseconds.
avg_wr_latency_ns: int
Average latency of write operations in the defined interval, in nanoseconds.
avg_flush_latency_ns: int
Average latency of flush operations in the defined interval, in nanoseconds.
avg_rd_queue_depth: number
Average number of pending read operations in the defined interval.
avg_wr_queue_depth: number
Average number of pending write operations in the defined interval.
Since

2.5

BlockDeviceStats (Object)

Statistics of a virtual block device or a block backing device.

Members
rd_bytes: int
The number of bytes read by the device.
wr_bytes: int
The number of bytes written by the device.
unmap_bytes: int
The number of bytes unmapped by the device (Since 4.2)
rd_operations: int
The number of read operations performed by the device.
wr_operations: int
The number of write operations performed by the device.
flush_operations: int
The number of cache flush operations performed by the device (since 0.15.0)
unmap_operations: int
The number of unmap operations performed by the device (Since 4.2)
rd_total_time_ns: int
Total time spent on reads in nanoseconds (since 0.15.0).
wr_total_time_ns: int
Total time spent on writes in nanoseconds (since 0.15.0).
flush_total_time_ns: int
Total time spent on cache flushes in nanoseconds (since 0.15.0).
unmap_total_time_ns: int
Total time spent on unmap operations in nanoseconds (Since 4.2)
wr_highest_offset: int
The offset after the greatest byte written to the device. The intended use of this information is for growable sparse files (like qcow2) that are used on top of a physical device.
rd_merged: int
Number of read requests that have been merged into another request (Since 2.3).
wr_merged: int
Number of write requests that have been merged into another request (Since 2.3).
unmap_merged: int
Number of unmap requests that have been merged into another request (Since 4.2)
idle_time_ns: int (optional)
Time since the last I/O operation, in nanoseconds. If the field is absent it means that there haven’t been any operations yet (Since 2.5).
failed_rd_operations: int
The number of failed read operations performed by the device (Since 2.5)
failed_wr_operations: int
The number of failed write operations performed by the device (Since 2.5)
failed_flush_operations: int
The number of failed flush operations performed by the device (Since 2.5)
failed_unmap_operations: int
The number of failed unmap operations performed by the device (Since 4.2)
invalid_rd_operations: int
The number of invalid read operations
performed by the device (Since 2.5)
invalid_wr_operations: int
The number of invalid write operations performed by the device (Since 2.5)
invalid_flush_operations: int
The number of invalid flush operations performed by the device (Since 2.5)
invalid_unmap_operations: int
The number of invalid unmap operations performed by the device (Since 4.2)
account_invalid: boolean
Whether invalid operations are included in the last access statistics (Since 2.5)
account_failed: boolean
Whether failed operations are included in the latency and last access statistics (Since 2.5)
timed_stats: array of BlockDeviceTimedStats
Statistics specific to the set of previously defined intervals of time (Since 2.5)
rd_latency_histogram: BlockLatencyHistogramInfo (optional)
BlockLatencyHistogramInfo. (Since 4.0)
wr_latency_histogram: BlockLatencyHistogramInfo (optional)
BlockLatencyHistogramInfo. (Since 4.0)
flush_latency_histogram: BlockLatencyHistogramInfo (optional)
BlockLatencyHistogramInfo. (Since 4.0)
Since

0.14.0

BlockStatsSpecificFile (Object)

File driver statistics

Members
discard-nb-ok: int
The number of successful discard operations performed by the driver.
discard-nb-failed: int
The number of failed discard operations performed by the driver.
discard-bytes-ok: int
The number of bytes discarded by the driver.
Since

4.2

BlockStatsSpecific (Object)

Block driver specific statistics

Members
driver: BlockdevDriver
Not documented
The members of BlockStatsSpecificFile when driver is "file"
The members of BlockStatsSpecificFile when driver is "host_device"
Since

4.2

BlockStats (Object)

Statistics of a virtual block device or a block backing device.

Members
device: string (optional)
If the stats are for a virtual block device, the name corresponding to the virtual block device.
node-name: string (optional)
The node name of the device. (Since 2.3)
qdev: string (optional)
The qdev ID, or if no ID is assigned, the QOM path of the block device. (since 3.0)
stats: BlockDeviceStats
A BlockDeviceStats for the device.
driver-specific: BlockStatsSpecific (optional)
Optional driver-specific stats. (Since 4.2)
parent: BlockStats (optional)
This describes the file block device if it has one. Contains recursively the statistics of the underlying protocol (e.g. the host file for a qcow2 image). If there is no underlying protocol, this field is omitted
backing: BlockStats (optional)
This describes the backing block device if it has one. (Since 2.0)
Since

0.14.0

query-blockstats (Command)

Query the BlockStats for all virtual block devices.

Arguments
query-nodes: boolean (optional)
If true, the command will query all the block nodes that have a node name, in a list which will include “parent” information, but not “backing”. If false or omitted, the behavior is as before - query all the device backends, recursively including their “parent” and “backing”. Filter nodes that were created implicitly are skipped over in this mode. (Since 2.3)
Returns

A list of BlockStats for each virtual block devices.

Since

0.14.0

Example
-> { "execute": "query-blockstats" }
<- {
      "return":[
         {
            "device":"ide0-hd0",
            "parent":{
               "stats":{
                  "wr_highest_offset":3686448128,
                  "wr_bytes":9786368,
                  "wr_operations":751,
                  "rd_bytes":122567168,
                  "rd_operations":36772
                  "wr_total_times_ns":313253456
                  "rd_total_times_ns":3465673657
                  "flush_total_times_ns":49653
                  "flush_operations":61,
                  "rd_merged":0,
                  "wr_merged":0,
                  "idle_time_ns":2953431879,
                  "account_invalid":true,
                  "account_failed":false
               }
            },
            "stats":{
               "wr_highest_offset":2821110784,
               "wr_bytes":9786368,
               "wr_operations":692,
               "rd_bytes":122739200,
               "rd_operations":36604
               "flush_operations":51,
               "wr_total_times_ns":313253456
               "rd_total_times_ns":3465673657
               "flush_total_times_ns":49653,
               "rd_merged":0,
               "wr_merged":0,
               "idle_time_ns":2953431879,
               "account_invalid":true,
               "account_failed":false
            },
            "qdev": "/machine/unattached/device[23]"
         },
         {
            "device":"ide1-cd0",
            "stats":{
               "wr_highest_offset":0,
               "wr_bytes":0,
               "wr_operations":0,
               "rd_bytes":0,
               "rd_operations":0
               "flush_operations":0,
               "wr_total_times_ns":0
               "rd_total_times_ns":0
               "flush_total_times_ns":0,
               "rd_merged":0,
               "wr_merged":0,
               "account_invalid":false,
               "account_failed":false
            },
            "qdev": "/machine/unattached/device[24]"
         },
         {
            "device":"floppy0",
            "stats":{
               "wr_highest_offset":0,
               "wr_bytes":0,
               "wr_operations":0,
               "rd_bytes":0,
               "rd_operations":0
               "flush_operations":0,
               "wr_total_times_ns":0
               "rd_total_times_ns":0
               "flush_total_times_ns":0,
               "rd_merged":0,
               "wr_merged":0,
               "account_invalid":false,
               "account_failed":false
            },
            "qdev": "/machine/unattached/device[16]"
         },
         {
            "device":"sd0",
            "stats":{
               "wr_highest_offset":0,
               "wr_bytes":0,
               "wr_operations":0,
               "rd_bytes":0,
               "rd_operations":0
               "flush_operations":0,
               "wr_total_times_ns":0
               "rd_total_times_ns":0
               "flush_total_times_ns":0,
               "rd_merged":0,
               "wr_merged":0,
               "account_invalid":false,
               "account_failed":false
            }
         }
      ]
   }

BlockdevOnError (Enum)

An enumeration of possible behaviors for errors on I/O operations. The exact meaning depends on whether the I/O was initiated by a guest or by a block job

Values
report
for guest operations, report the error to the guest; for jobs, cancel the job
ignore
ignore the error, only report a QMP event (BLOCK_IO_ERROR or BLOCK_JOB_ERROR). The backup, mirror and commit block jobs retry the failing request later and may still complete successfully. The stream block job continues to stream and will complete with an error.
enospc
same as stop on ENOSPC, same as report otherwise.
stop
for guest operations, stop the virtual machine; for jobs, pause the job
auto
inherit the error handling policy of the backend (since: 2.7)
Since

1.3

MirrorSyncMode (Enum)

An enumeration of possible behaviors for the initial synchronization phase of storage mirroring.

Values
top
copies data in the topmost image to the destination
full
copies data from all images to the destination
none
only copy data written from now on
incremental
only copy data described by the dirty bitmap. (since: 2.4)
bitmap
only copy data described by the dirty bitmap. (since: 4.2) Behavior on completion is determined by the BitmapSyncMode.
Since

1.3

BitmapSyncMode (Enum)

An enumeration of possible behaviors for the synchronization of a bitmap when used for data copy operations.

Values
on-success
The bitmap is only synced when the operation is successful. This is the behavior always used for ‘INCREMENTAL’ backups.
never
The bitmap is never synchronized with the operation, and is treated solely as a read-only manifest of blocks to copy.
always
The bitmap is always synchronized with the operation, regardless of whether or not the operation was successful.
Since

4.2

MirrorCopyMode (Enum)

An enumeration whose values tell the mirror block job when to trigger writes to the target.

Values
background
copy data in background only.
write-blocking
when data is written to the source, write it (synchronously) to the target as well. In addition, data is copied in background just like in background mode.
Since

3.0

BlockJobInfo (Object)

Information about a long-running block device operation.

Members
type: string
the job type (‘stream’ for image streaming)
device: string
The job identifier. Originally the device name but other values are allowed since QEMU 2.7
len: int
Estimated offset value at the completion of the job. This value can arbitrarily change while the job is running, in both directions.
offset: int
Progress made until now. The unit is arbitrary and the value can only meaningfully be used for the ratio of offset to len. The value is monotonically increasing.
busy: boolean
false if the job is known to be in a quiescent state, with no pending I/O. Since 1.3.
paused: boolean
whether the job is paused or, if busy is true, will pause itself as soon as possible. Since 1.3.
speed: int
the rate limit, bytes per second
io-status: BlockDeviceIoStatus
the status of the job (since 1.3)
ready: boolean
true if the job may be completed (since 2.2)
status: JobStatus
Current job state/status (since 2.12)
auto-finalize: boolean
Job will finalize itself when PENDING, moving to the CONCLUDED state. (since 2.12)
auto-dismiss: boolean
Job will dismiss itself when CONCLUDED, moving to the NULL state and disappearing from the query list. (since 2.12)
error: string (optional)
Error information if the job did not complete successfully. Not set if the job completed successfully. (since 2.12.1)
Since

1.1

query-block-jobs (Command)

Return information about long-running block device operations.

Returns

a list of BlockJobInfo for each active block job

Since

1.1

block_passwd (Command)

This command sets the password of a block device that has not been open with a password and requires one.

This command is now obsolete and will always return an error since 2.10

Arguments
device: string (optional)
Not documented
node-name: string (optional)
Not documented
password: string
Not documented

block_resize (Command)

Resize a block image while a guest is running.

Either device or node-name must be set but not both.

Arguments
device: string (optional)
the name of the device to get the image resized
node-name: string (optional)
graph node name to get the image resized (Since 2.0)
size: int
new image size in bytes
Returns
  • nothing on success
  • If device is not a valid block device, DeviceNotFound
Since

0.14.0

Example
-> { "execute": "block_resize",
     "arguments": { "device": "scratch", "size": 1073741824 } }
<- { "return": {} }

NewImageMode (Enum)

An enumeration that tells QEMU how to set the backing file path in a new image file.

Values
existing
QEMU should look for an existing image file.
absolute-paths
QEMU should create a new image with absolute paths for the backing file. If there is no backing file available, the new image will not be backed either.
Since

1.1

BlockdevSnapshotSync (Object)

Either device or node-name must be set but not both.

Members
device: string (optional)
the name of the device to take a snapshot of.
node-name: string (optional)
graph node name to generate the snapshot from (Since 2.0)
snapshot-file: string
the target of the new overlay image. If the file exists, or if it is a device, the overlay will be created in the existing file/device. Otherwise, a new file will be created.
snapshot-node-name: string (optional)
the graph node name of the new image (Since 2.0)
format: string (optional)
the format of the overlay image, default is ‘qcow2’.
mode: NewImageMode (optional)
whether and how QEMU should create a new image, default is ‘absolute-paths’.

BlockdevSnapshot (Object)

Members
node: string
device or node name that will have a snapshot taken.
overlay: string
reference to the existing block device that will become the overlay of node, as part of taking the snapshot. It must not have a current backing file (this can be achieved by passing “backing”: null to blockdev-add).
Since

2.5

BackupCommon (Object)

Members
job-id: string (optional)
identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)
device: string
the device name or node-name of a root node which should be copied.
sync: MirrorSyncMode
what parts of the disk image should be copied to the destination (all the disk, only the sectors allocated in the topmost image, from a dirty bitmap, or only new I/O).
speed: int (optional)
the maximum speed, in bytes per second. The default is 0, for unlimited.
bitmap: string (optional)
The name of a dirty bitmap to use. Must be present if sync is “bitmap” or “incremental”. Can be present if sync is “full” or “top”. Must not be present otherwise. (Since 2.4 (drive-backup), 3.1 (blockdev-backup))
bitmap-mode: BitmapSyncMode (optional)
Specifies the type of data the bitmap should contain after the operation concludes. Must be present if a bitmap was provided, Must NOT be present otherwise. (Since 4.2)
compress: boolean (optional)
true to compress data, if the target format supports it. (default: false) (since 2.8)
on-source-error: BlockdevOnError (optional)
the action to take on an error on the source, default ‘report’. ‘stop’ and ‘enospc’ can only be used if the block device supports io-status (see BlockInfo).
on-target-error: BlockdevOnError (optional)
the action to take on an error on the target, default ‘report’ (no limitations, since this applies to a different block device than device).
auto-finalize: boolean (optional)
When false, this job will wait in a PENDING state after it has finished its work, waiting for block-job-finalize before making any block graph changes. When true, this job will automatically perform its abort or commit actions. Defaults to true. (Since 2.12)
auto-dismiss: boolean (optional)
When false, this job will wait in a CONCLUDED state after it has completely ceased all work, and awaits block-job-dismiss. When true, this job will automatically disappear from the query list without user intervention. Defaults to true. (Since 2.12)
filter-node-name: string (optional)
the node name that should be assigned to the filter driver that the backup job inserts into the graph above node specified by drive. If this option is not given, a node name is autogenerated. (Since: 4.2)
Note

on-source-error and on-target-error only affect background I/O. If an error occurs during a guest write request, the device’s rerror/werror actions will be used.

Since

4.2

DriveBackup (Object)

Members
target: string
the target of the new image. If the file exists, or if it is a device, the existing file/device will be used as the new destination. If it does not exist, a new file will be created.
format: string (optional)
the format of the new destination, default is to probe if mode is ‘existing’, else the format of the source
mode: NewImageMode (optional)
whether and how QEMU should create a new image, default is ‘absolute-paths’.
The members of BackupCommon
Since

1.6

BlockdevBackup (Object)

Members
target: string
the device name or node-name of the backup target node.
The members of BackupCommon
Since

2.3

blockdev-snapshot-sync (Command)

Takes a synchronous snapshot of a block device.

For the arguments, see the documentation of BlockdevSnapshotSync.

Returns
  • nothing on success
  • If device is not a valid block device, DeviceNotFound
Since

0.14.0

Example
-> { "execute": "blockdev-snapshot-sync",
     "arguments": { "device": "ide-hd0",
                    "snapshot-file":
                    "/some/place/my-image",
                    "format": "qcow2" } }
<- { "return": {} }

blockdev-snapshot (Command)

Takes a snapshot of a block device.

Take a snapshot, by installing ‘node’ as the backing image of ‘overlay’. Additionally, if ‘node’ is associated with a block device, the block device changes to using ‘overlay’ as its new active image.

For the arguments, see the documentation of BlockdevSnapshot.

Since

2.5

Example
-> { "execute": "blockdev-add",
     "arguments": { "driver": "qcow2",
                    "node-name": "node1534",
                    "file": { "driver": "file",
                              "filename": "hd1.qcow2" },
                    "backing": null } }

<- { "return": {} }

-> { "execute": "blockdev-snapshot",
     "arguments": { "node": "ide-hd0",
                    "overlay": "node1534" } }
<- { "return": {} }

change-backing-file (Command)

Change the backing file in the image file metadata. This does not cause QEMU to reopen the image file to reparse the backing filename (it may, however, perform a reopen to change permissions from r/o -> r/w -> r/o, if needed). The new backing file string is written into the image file metadata, and the QEMU internal strings are updated.

Arguments
image-node-name: string
The name of the block driver state node of the image to modify. The “device” argument is used to verify “image-node-name” is in the chain described by “device”.
device: string
The device name or node-name of the root node that owns image-node-name.
backing-file: string
The string to write as the backing file. This string is not validated, so care should be taken when specifying the string or the image chain may not be able to be reopened again.
Returns
  • Nothing on success
  • If “device” does not exist or cannot be determined, DeviceNotFound
Since

2.1

block-commit (Command)

Live commit of data from overlay image nodes into backing nodes - i.e., writes data between ‘top’ and ‘base’ into ‘base’.

Arguments
job-id: string (optional)
identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)
device: string
the device name or node-name of a root node
base-node: string (optional)
The node name of the backing image to write data into. If not specified, this is the deepest backing image. (since: 3.1)
base: string (optional)
Same as base-node, except that it is a file name rather than a node name. This must be the exact filename string that was used to open the node; other strings, even if addressing the same file, are not accepted (deprecated, use base-node instead)
top-node: string (optional)
The node name of the backing image within the image chain which contains the topmost data to be committed down. If not specified, this is the active layer. (since: 3.1)
top: string (optional)
Same as top-node, except that it is a file name rather than a node name. This must be the exact filename string that was used to open the node; other strings, even if addressing the same file, are not accepted (deprecated, use base-node instead)
backing-file: string (optional)

The backing file string to write into the overlay image of ‘top’. If ‘top’ is the active layer, specifying a backing file string is an error. This filename is not validated.

If a pathname string is such that it cannot be resolved by QEMU, that means that subsequent QMP or HMP commands must use node-names for the image in question, as filename lookup methods will fail.

If not specified, QEMU will automatically determine the backing file string to use, or error out if there is no obvious choice. Care should be taken when specifying the string, to specify a valid filename or protocol. (Since 2.1)

If top == base, that is an error. If top == active, the job will not be completed by itself, user needs to complete the job with the block-job-complete command after getting the ready event. (Since 2.0)

If the base image is smaller than top, then the base image will be resized to be the same size as top. If top is smaller than the base image, the base will not be truncated. If you want the base image size to match the size of the smaller top, you can safely truncate it yourself once the commit operation successfully completes.

speed: int (optional)
the maximum speed, in bytes per second
on-error: BlockdevOnError (optional)
the action to take on an error. ‘ignore’ means that the request should be retried. (default: report; Since: 5.0)
filter-node-name: string (optional)
the node name that should be assigned to the filter driver that the commit job inserts into the graph above top. If this option is not given, a node name is autogenerated. (Since: 2.9)
auto-finalize: boolean (optional)
When false, this job will wait in a PENDING state after it has finished its work, waiting for block-job-finalize before making any block graph changes. When true, this job will automatically perform its abort or commit actions. Defaults to true. (Since 3.1)
auto-dismiss: boolean (optional)
When false, this job will wait in a CONCLUDED state after it has completely ceased all work, and awaits block-job-dismiss. When true, this job will automatically disappear from the query list without user intervention. Defaults to true. (Since 3.1)
Returns
  • Nothing on success
  • If device does not exist, DeviceNotFound
  • Any other error returns a GenericError.
Since

1.3

Example
-> { "execute": "block-commit",
     "arguments": { "device": "virtio0",
                    "top": "/tmp/snap1.qcow2" } }
<- { "return": {} }

drive-backup (Command)

Start a point-in-time copy of a block device to a new destination. The status of ongoing drive-backup operations can be checked with query-block-jobs where the BlockJobInfo.type field has the value ‘backup’. The operation can be stopped before it has completed using the block-job-cancel command.

Arguments
The members of DriveBackup
Returns
  • nothing on success
  • If device is not a valid block device, GenericError
Since

1.6

Example
-> { "execute": "drive-backup",
     "arguments": { "device": "drive0",
                    "sync": "full",
                    "target": "backup.img" } }
<- { "return": {} }

blockdev-backup (Command)

Start a point-in-time copy of a block device to a new destination. The status of ongoing blockdev-backup operations can be checked with query-block-jobs where the BlockJobInfo.type field has the value ‘backup’. The operation can be stopped before it has completed using the block-job-cancel command.

Arguments
The members of BlockdevBackup
Returns
  • nothing on success
  • If device is not a valid block device, DeviceNotFound
Since

2.3

Example
-> { "execute": "blockdev-backup",
     "arguments": { "device": "src-id",
                    "sync": "full",
                    "target": "tgt-id" } }
<- { "return": {} }

query-named-block-nodes (Command)

Get the named block driver list

Arguments
flat: boolean (optional)
Omit the nested data about backing image (“backing-image” key) if true. Default is false (Since 5.0)
Returns

the list of BlockDeviceInfo

Since

2.0

Example
-> { "execute": "query-named-block-nodes" }
<- { "return": [ { "ro":false,
                   "drv":"qcow2",
                   "encrypted":false,
                   "file":"disks/test.qcow2",
                   "node-name": "my-node",
                   "backing_file_depth":1,
                   "bps":1000000,
                   "bps_rd":0,
                   "bps_wr":0,
                   "iops":1000000,
                   "iops_rd":0,
                   "iops_wr":0,
                   "bps_max": 8000000,
                   "bps_rd_max": 0,
                   "bps_wr_max": 0,
                   "iops_max": 0,
                   "iops_rd_max": 0,
                   "iops_wr_max": 0,
                   "iops_size": 0,
                   "write_threshold": 0,
                   "image":{
                      "filename":"disks/test.qcow2",
                      "format":"qcow2",
                      "virtual-size":2048000,
                      "backing_file":"base.qcow2",
                      "full-backing-filename":"disks/base.qcow2",
                      "backing-filename-format":"qcow2",
                      "snapshots":[
                         {
                            "id": "1",
                            "name": "snapshot1",
                            "vm-state-size": 0,
                            "date-sec": 10000200,
                            "date-nsec": 12,
                            "vm-clock-sec": 206,
                            "vm-clock-nsec": 30
                         }
                      ],
                      "backing-image":{
                          "filename":"disks/base.qcow2",
                          "format":"qcow2",
                          "virtual-size":2048000
                      }
                   } } ] }

XDbgBlockGraphNodeType (Enum)

Values
block-backend
corresponds to BlockBackend
block-job
corresonds to BlockJob
block-driver
corresponds to BlockDriverState
Since

4.0

XDbgBlockGraphNode (Object)

Members
id: int
Block graph node identifier. This id is generated only for x-debug-query-block-graph and does not relate to any other identifiers in Qemu.
type: XDbgBlockGraphNodeType
Type of graph node. Can be one of block-backend, block-job or block-driver-state.
name: string
Human readable name of the node. Corresponds to node-name for block-driver-state nodes; is not guaranteed to be unique in the whole graph (with block-jobs and block-backends).
Since

4.0

BlockPermission (Enum)

Enum of base block permissions.

Values
consistent-read
A user that has the “permission” of consistent reads is guaranteed that their view of the contents of the block device is complete and self-consistent, representing the contents of a disk at a specific point. For most block devices (including their backing files) this is true, but the property cannot be maintained in a few situations like for intermediate nodes of a commit block job.
write
This permission is required to change the visible disk contents.
write-unchanged
This permission (which is weaker than BLK_PERM_WRITE) is both enough and required for writes to the block node when the caller promises that the visible disk content doesn’t change. As the BLK_PERM_WRITE permission is strictly stronger, either is sufficient to perform an unchanging write.
resize
This permission is required to change the size of a block node.
graph-mod
This permission is required to change the node that this BdrvChild points to.
Since

4.0

XDbgBlockGraphEdge (Object)

Block Graph edge description for x-debug-query-block-graph.

Members
parent: int
parent id
child: int
child id
name: string
name of the relation (examples are ‘file’ and ‘backing’)
perm: array of BlockPermission
granted permissions for the parent operating on the child
shared-perm: array of BlockPermission
permissions that can still be granted to other users of the child while it is still attached to this parent
Since

4.0

XDbgBlockGraph (Object)

Block Graph - list of nodes and list of edges.

Members
nodes: array of XDbgBlockGraphNode
Not documented
edges: array of XDbgBlockGraphEdge
Not documented
Since

4.0

x-debug-query-block-graph (Command)

Get the block graph.

Since

4.0

drive-mirror (Command)

Start mirroring a block device’s writes to a new destination. target specifies the target of the new image. If the file exists, or if it is a device, it will be used as the new destination for writes. If it does not exist, a new file will be created. format specifies the format of the mirror image, default is to probe if mode=’existing’, else the format of the source.

Arguments
The members of DriveMirror
Returns
  • nothing on success
  • If device is not a valid block device, GenericError
Since

1.3

Example
-> { "execute": "drive-mirror",
     "arguments": { "device": "ide-hd0",
                    "target": "/some/place/my-image",
                    "sync": "full",
                    "format": "qcow2" } }
<- { "return": {} }

DriveMirror (Object)

A set of parameters describing drive mirror setup.

Members
job-id: string (optional)
identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)
device: string
the device name or node-name of a root node whose writes should be
mirrored.
target: string
the target of the new image. If the file exists, or if it is a device, the existing file/device will be used as the new destination. If it does not exist, a new file will be created.
format: string (optional)
the format of the new destination, default is to probe if mode is ‘existing’, else the format of the source
node-name: string (optional)
the new block driver state node name in the graph (Since 2.1)
replaces: string (optional)
with sync=full graph node name to be replaced by the new image when a whole image copy is done. This can be used to repair broken Quorum files. (Since 2.1)
mode: NewImageMode (optional)
whether and how QEMU should create a new image, default is ‘absolute-paths’.
speed: int (optional)
the maximum speed, in bytes per second
sync: MirrorSyncMode
what parts of the disk image should be copied to the destination (all the disk, only the sectors allocated in the topmost image, or only new I/O).
granularity: int (optional)
granularity of the dirty bitmap, default is 64K if the image format doesn’t have clusters, 4K if the clusters are smaller than that, else the cluster size. Must be a power of 2 between 512 and 64M (since 1.4).
buf-size: int (optional)
maximum amount of data in flight from source to target (since 1.4).
on-source-error: BlockdevOnError (optional)
the action to take on an error on the source, default ‘report’. ‘stop’ and ‘enospc’ can only be used if the block device supports io-status (see BlockInfo).
on-target-error: BlockdevOnError (optional)
the action to take on an error on the target, default ‘report’ (no limitations, since this applies to a different block device than device).
unmap: boolean (optional)
Whether to try to unmap target sectors where source has only zero. If true, and target unallocated sectors will read as zero, target image sectors will be unmapped; otherwise, zeroes will be written. Both will result in identical contents. Default is true. (Since 2.4)
copy-mode: MirrorCopyMode (optional)
when to copy data to the destination; defaults to ‘background’ (Since: 3.0)
auto-finalize: boolean (optional)
When false, this job will wait in a PENDING state after it has finished its work, waiting for block-job-finalize before making any block graph changes. When true, this job will automatically perform its abort or commit actions. Defaults to true. (Since 3.1)
auto-dismiss: boolean (optional)
When false, this job will wait in a CONCLUDED state after it has completely ceased all work, and awaits block-job-dismiss. When true, this job will automatically disappear from the query list without user intervention. Defaults to true. (Since 3.1)
Since

1.3

BlockDirtyBitmap (Object)

Members
node: string
name of device/node which the bitmap is tracking
name: string
name of the dirty bitmap
Since

2.4

BlockDirtyBitmapAdd (Object)

Members
node: string
name of device/node which the bitmap is tracking
name: string
name of the dirty bitmap (must be less than 1024 bytes)
granularity: int (optional)
the bitmap granularity, default is 64k for block-dirty-bitmap-add
persistent: boolean (optional)
the bitmap is persistent, i.e. it will be saved to the corresponding block device image file on its close. For now only Qcow2 disks support persistent bitmaps. Default is false for block-dirty-bitmap-add. (Since: 2.10)
disabled: boolean (optional)
the bitmap is created in the disabled state, which means that it will not track drive changes. The bitmap may be enabled with block-dirty-bitmap-enable. Default is false. (Since: 4.0)
Since

2.4

BlockDirtyBitmapMergeSource (Alternate)

Members
local: string
name of the bitmap, attached to the same node as target bitmap.
external: BlockDirtyBitmap
bitmap with specified node
Since

4.1

BlockDirtyBitmapMerge (Object)

Members
node: string
name of device/node which the target bitmap is tracking
target: string
name of the destination dirty bitmap
bitmaps: array of BlockDirtyBitmapMergeSource
name(s) of the source dirty bitmap(s) at node and/or fully specifed BlockDirtyBitmap elements. The latter are supported since 4.1.
Since

4.0

block-dirty-bitmap-add (Command)

Create a dirty bitmap with a name on the node, and start tracking the writes.

Returns
  • nothing on success
  • If node is not a valid block device or node, DeviceNotFound
  • If name is already taken, GenericError with an explanation
Since

2.4

Example
-> { "execute": "block-dirty-bitmap-add",
     "arguments": { "node": "drive0", "name": "bitmap0" } }
<- { "return": {} }

block-dirty-bitmap-remove (Command)

Stop write tracking and remove the dirty bitmap that was created with block-dirty-bitmap-add. If the bitmap is persistent, remove it from its storage too.

Returns
  • nothing on success
  • If node is not a valid block device or node, DeviceNotFound
  • If name is not found, GenericError with an explanation
  • if name is frozen by an operation, GenericError
Since

2.4

Example
-> { "execute": "block-dirty-bitmap-remove",
     "arguments": { "node": "drive0", "name": "bitmap0" } }
<- { "return": {} }

block-dirty-bitmap-clear (Command)

Clear (reset) a dirty bitmap on the device, so that an incremental backup from this point in time forward will only backup clusters modified after this clear operation.

Returns
  • nothing on success
  • If node is not a valid block device, DeviceNotFound
  • If name is not found, GenericError with an explanation
Since

2.4

Example
-> { "execute": "block-dirty-bitmap-clear",
     "arguments": { "node": "drive0", "name": "bitmap0" } }
<- { "return": {} }

block-dirty-bitmap-enable (Command)

Enables a dirty bitmap so that it will begin tracking disk changes.

Returns
  • nothing on success
  • If node is not a valid block device, DeviceNotFound
  • If name is not found, GenericError with an explanation
Since

4.0

Example
-> { "execute": "block-dirty-bitmap-enable",
     "arguments": { "node": "drive0", "name": "bitmap0" } }
<- { "return": {} }

block-dirty-bitmap-disable (Command)

Disables a dirty bitmap so that it will stop tracking disk changes.

Returns
  • nothing on success
  • If node is not a valid block device, DeviceNotFound
  • If name is not found, GenericError with an explanation
Since

4.0

Example
-> { "execute": "block-dirty-bitmap-disable",
     "arguments": { "node": "drive0", "name": "bitmap0" } }
<- { "return": {} }

block-dirty-bitmap-merge (Command)

Merge dirty bitmaps listed in bitmaps to the target dirty bitmap. Dirty bitmaps in bitmaps will be unchanged, except if it also appears as the target bitmap. Any bits already set in target will still be set after the merge, i.e., this operation does not clear the target. On error, target is unchanged.

The resulting bitmap will count as dirty any clusters that were dirty in any of the source bitmaps. This can be used to achieve backup checkpoints, or in simpler usages, to copy bitmaps.

Returns
  • nothing on success
  • If node is not a valid block device, DeviceNotFound
  • If any bitmap in bitmaps or target is not found, GenericError
  • If any of the bitmaps have different sizes or granularities, GenericError
Since

4.0

Example
-> { "execute": "block-dirty-bitmap-merge",
     "arguments": { "node": "drive0", "target": "bitmap0",
                    "bitmaps": ["bitmap1"] } }
<- { "return": {} }

BlockDirtyBitmapSha256 (Object)

SHA256 hash of dirty bitmap data

Members
sha256: string
ASCII representation of SHA256 bitmap hash
Since

2.10

x-debug-block-dirty-bitmap-sha256 (Command)

Get bitmap SHA256.

Returns
  • BlockDirtyBitmapSha256 on success
  • If node is not a valid block device, DeviceNotFound
  • If name is not found or if hashing has failed, GenericError with an explanation
Since

2.10

blockdev-mirror (Command)

Start mirroring a block device’s writes to a new destination.

Arguments
job-id: string (optional)
identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)
device: string
The device name or node-name of a root node whose writes should be mirrored.
target: string
the id or node-name of the block device to mirror to. This mustn’t be attached to guest.
replaces: string (optional)
with sync=full graph node name to be replaced by the new image when a whole image copy is done. This can be used to repair broken Quorum files.
speed: int (optional)
the maximum speed, in bytes per second
sync: MirrorSyncMode
what parts of the disk image should be copied to the destination (all the disk, only the sectors allocated in the topmost image, or only new I/O).
granularity: int (optional)
granularity of the dirty bitmap, default is 64K if the image format doesn’t have clusters, 4K if the clusters are smaller than that, else the cluster size. Must be a power of 2 between 512 and 64M
buf-size: int (optional)
maximum amount of data in flight from source to target
on-source-error: BlockdevOnError (optional)
the action to take on an error on the source, default ‘report’. ‘stop’ and ‘enospc’ can only be used if the block device supports io-status (see BlockInfo).
on-target-error: BlockdevOnError (optional)
the action to take on an error on the target, default ‘report’ (no limitations, since this applies to a different block device than device).
filter-node-name: string (optional)
the node name that should be assigned to the filter driver that the mirror job inserts into the graph above device. If this option is not given, a node name is autogenerated. (Since: 2.9)
copy-mode: MirrorCopyMode (optional)
when to copy data to the destination; defaults to ‘background’ (Since: 3.0)
auto-finalize: boolean (optional)
When false, this job will wait in a PENDING state after it has finished its work, waiting for block-job-finalize before making any block graph changes. When true, this job will automatically perform its abort or commit actions. Defaults to true. (Since 3.1)
auto-dismiss: boolean (optional)
When false, this job will wait in a CONCLUDED state after it has completely ceased all work, and awaits block-job-dismiss. When true, this job will automatically disappear from the query list without user intervention. Defaults to true. (Since 3.1)
Returns

nothing on success.

Since

2.6

Example
-> { "execute": "blockdev-mirror",
     "arguments": { "device": "ide-hd0",
                    "target": "target0",
                    "sync": "full" } }
<- { "return": {} }

block_set_io_throttle (Command)

Change I/O throttle limits for a block drive.

Since QEMU 2.4, each device with I/O limits is member of a throttle group.

If two or more devices are members of the same group, the limits will apply to the combined I/O of the whole group in a round-robin fashion. Therefore, setting new I/O limits to a device will affect the whole group.

The name of the group can be specified using the ‘group’ parameter. If the parameter is unset, it is assumed to be the current group of that device. If it’s not in any group yet, the name of the device will be used as the name for its group.

The ‘group’ parameter can also be used to move a device to a different group. In this case the limits specified in the parameters will be applied to the new group only.

I/O limits can be disabled by setting all of them to 0. In this case the device will be removed from its group and the rest of its members will not be affected. The ‘group’ parameter is ignored.

Arguments
The members of BlockIOThrottle
Returns
  • Nothing on success
  • If device is not a valid block device, DeviceNotFound
Since

1.1

Example
-> { "execute": "block_set_io_throttle",
     "arguments": { "id": "virtio-blk-pci0/virtio-backend",
                    "bps": 0,
                    "bps_rd": 0,
                    "bps_wr": 0,
                    "iops": 512,
                    "iops_rd": 0,
                    "iops_wr": 0,
                    "bps_max": 0,
                    "bps_rd_max": 0,
                    "bps_wr_max": 0,
                    "iops_max": 0,
                    "iops_rd_max": 0,
                    "iops_wr_max": 0,
                    "bps_max_length": 0,
                    "iops_size": 0 } }
<- { "return": {} }

-> { "execute": "block_set_io_throttle",
     "arguments": { "id": "ide0-1-0",
                    "bps": 1000000,
                    "bps_rd": 0,
                    "bps_wr": 0,
                    "iops": 0,
                    "iops_rd": 0,
                    "iops_wr": 0,
                    "bps_max": 8000000,
                    "bps_rd_max": 0,
                    "bps_wr_max": 0,
                    "iops_max": 0,
                    "iops_rd_max": 0,
                    "iops_wr_max": 0,
                    "bps_max_length": 60,
                    "iops_size": 0 } }
<- { "return": {} }

BlockIOThrottle (Object)

A set of parameters describing block throttling.

Members
device: string (optional)
Block device name (deprecated, use id instead)
id: string (optional)
The name or QOM path of the guest device (since: 2.8)
bps: int
total throughput limit in bytes per second
bps_rd: int
read throughput limit in bytes per second
bps_wr: int
write throughput limit in bytes per second
iops: int
total I/O operations per second
iops_rd: int
read I/O operations per second
iops_wr: int
write I/O operations per second
bps_max: int (optional)
total throughput limit during bursts, in bytes (Since 1.7)
bps_rd_max: int (optional)
read throughput limit during bursts, in bytes (Since 1.7)
bps_wr_max: int (optional)
write throughput limit during bursts, in bytes (Since 1.7)
iops_max: int (optional)
total I/O operations per second during bursts, in bytes (Since 1.7)
iops_rd_max: int (optional)
read I/O operations per second during bursts, in bytes (Since 1.7)
iops_wr_max: int (optional)
write I/O operations per second during bursts, in bytes (Since 1.7)
bps_max_length: int (optional)
maximum length of the bps_max burst period, in seconds. It must only be set if bps_max is set as well. Defaults to 1. (Since 2.6)
bps_rd_max_length: int (optional)
maximum length of the bps_rd_max burst period, in seconds. It must only be set if bps_rd_max is set as well. Defaults to 1. (Since 2.6)
bps_wr_max_length: int (optional)
maximum length of the bps_wr_max burst period, in seconds. It must only be set if bps_wr_max is set as well. Defaults to 1. (Since 2.6)
iops_max_length: int (optional)
maximum length of the iops burst period, in seconds. It must only be set if iops_max is set as well. Defaults to 1. (Since 2.6)
iops_rd_max_length: int (optional)
maximum length of the iops_rd_max burst period, in seconds. It must only be set if iops_rd_max is set as well. Defaults to 1. (Since 2.6)
iops_wr_max_length: int (optional)
maximum length of the iops_wr_max burst period, in seconds. It must only be set if iops_wr_max is set as well. Defaults to 1. (Since 2.6)
iops_size: int (optional)
an I/O size in bytes (Since 1.7)
group: string (optional)
throttle group name (Since 2.4)
Since

1.1

ThrottleLimits (Object)

Limit parameters for throttling. Since some limit combinations are illegal, limits should always be set in one transaction. All fields are optional. When setting limits, if a field is missing the current value is not changed.

Members
iops-total: int (optional)
limit total I/O operations per second
iops-total-max: int (optional)
I/O operations burst
iops-total-max-length: int (optional)
length of the iops-total-max burst period, in seconds It must only be set if iops-total-max is set as well.
iops-read: int (optional)
limit read operations per second
iops-read-max: int (optional)
I/O operations read burst
iops-read-max-length: int (optional)
length of the iops-read-max burst period, in seconds It must only be set if iops-read-max is set as well.
iops-write: int (optional)
limit write operations per second
iops-write-max: int (optional)
I/O operations write burst
iops-write-max-length: int (optional)
length of the iops-write-max burst period, in seconds It must only be set if iops-write-max is set as well.
bps-total: int (optional)
limit total bytes per second
bps-total-max: int (optional)
total bytes burst
bps-total-max-length: int (optional)
length of the bps-total-max burst period, in seconds. It must only be set if bps-total-max is set as well.
bps-read: int (optional)
limit read bytes per second
bps-read-max: int (optional)
total bytes read burst
bps-read-max-length: int (optional)
length of the bps-read-max burst period, in seconds It must only be set if bps-read-max is set as well.
bps-write: int (optional)
limit write bytes per second
bps-write-max: int (optional)
total bytes write burst
bps-write-max-length: int (optional)
length of the bps-write-max burst period, in seconds It must only be set if bps-write-max is set as well.
iops-size: int (optional)
when limiting by iops max size of an I/O in bytes
Since

2.11

block-stream (Command)

Copy data from a backing file into a block device.

The block streaming operation is performed in the background until the entire backing file has been copied. This command returns immediately once streaming has started. The status of ongoing block streaming operations can be checked with query-block-jobs. The operation can be stopped before it has completed using the block-job-cancel command.

The node that receives the data is called the top image, can be located in any part of the chain (but always above the base image; see below) and can be specified using its device or node name. Earlier qemu versions only allowed ‘device’ to name the top level node; presence of the ‘base-node’ parameter during introspection can be used as a witness of the enhanced semantics of ‘device’.

If a base file is specified then sectors are not copied from that base file and its backing chain. When streaming completes the image file will have the base file as its backing file. This can be used to stream a subset of the backing file chain instead of flattening the entire image.

On successful completion the image file is updated to drop the backing file and the BLOCK_JOB_COMPLETED event is emitted.

Arguments
job-id: string (optional)
identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)
device: string
the device or node name of the top image
base: string (optional)
the common backing file name. It cannot be set if base-node is also set.
base-node: string (optional)
the node name of the backing file. It cannot be set if base is also set. (Since 2.8)
backing-file: string (optional)

The backing file string to write into the top image. This filename is not validated.

If a pathname string is such that it cannot be resolved by QEMU, that means that subsequent QMP or HMP commands must use node-names for the image in question, as filename lookup methods will fail.

If not specified, QEMU will automatically determine the backing file string to use, or error out if there is no obvious choice. Care should be taken when specifying the string, to specify a valid filename or protocol. (Since 2.1)

speed: int (optional)
the maximum speed, in bytes per second
on-error: BlockdevOnError (optional)
the action to take on an error (default report). ‘stop’ and ‘enospc’ can only be used if the block device supports io-status (see BlockInfo). Since 1.3.
auto-finalize: boolean (optional)
When false, this job will wait in a PENDING state after it has finished its work, waiting for block-job-finalize before making any block graph changes. When true, this job will automatically perform its abort or commit actions. Defaults to true. (Since 3.1)
auto-dismiss: boolean (optional)
When false, this job will wait in a CONCLUDED state after it has completely ceased all work, and awaits block-job-dismiss. When true, this job will automatically disappear from the query list without user intervention. Defaults to true. (Since 3.1)
Returns
  • Nothing on success.
  • If device does not exist, DeviceNotFound.
Since

1.1

Example
-> { "execute": "block-stream",
     "arguments": { "device": "virtio0",
                    "base": "/tmp/master.qcow2" } }
<- { "return": {} }

block-job-set-speed (Command)

Set maximum speed for a background block operation.

This command can only be issued when there is an active block job.

Throttling can be disabled by setting the speed to 0.

Arguments
device: string
The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.
speed: int
the maximum speed, in bytes per second, or 0 for unlimited. Defaults to 0.
Returns
  • Nothing on success
  • If no background operation is active on this device, DeviceNotActive
Since

1.1

block-job-cancel (Command)

Stop an active background block operation.

This command returns immediately after marking the active background block operation for cancellation. It is an error to call this command if no operation is in progress.

The operation will cancel as soon as possible and then emit the BLOCK_JOB_CANCELLED event. Before that happens the job is still visible when enumerated using query-block-jobs.

Note that if you issue ‘block-job-cancel’ after ‘drive-mirror’ has indicated (via the event BLOCK_JOB_READY) that the source and destination are synchronized, then the event triggered by this command changes to BLOCK_JOB_COMPLETED, to indicate that the mirroring has ended and the destination now has a point-in-time copy tied to the time of the cancellation.

For streaming, the image file retains its backing file unless the streaming operation happens to complete just as it is being cancelled. A new streaming operation can be started at a later time to finish copying all data from the backing file.

Arguments
device: string
The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.
force: boolean (optional)
If true, and the job has already emitted the event BLOCK_JOB_READY, abandon the job immediately (even if it is paused) instead of waiting for the destination to complete its final synchronization (since 1.3)
Returns
  • Nothing on success
  • If no background operation is active on this device, DeviceNotActive
Since

1.1

block-job-pause (Command)

Pause an active background block operation.

This command returns immediately after marking the active background block operation for pausing. It is an error to call this command if no operation is in progress or if the job is already paused.

The operation will pause as soon as possible. No event is emitted when the operation is actually paused. Cancelling a paused job automatically resumes it.

Arguments
device: string
The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.
Returns
  • Nothing on success
  • If no background operation is active on this device, DeviceNotActive
Since

1.3

block-job-resume (Command)

Resume an active background block operation.

This command returns immediately after resuming a paused background block operation. It is an error to call this command if no operation is in progress or if the job is not paused.

This command also clears the error status of the job.

Arguments
device: string
The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.
Returns
  • Nothing on success
  • If no background operation is active on this device, DeviceNotActive
Since

1.3

block-job-complete (Command)

Manually trigger completion of an active background block operation. This is supported for drive mirroring, where it also switches the device to write to the target path only. The ability to complete is signaled with a BLOCK_JOB_READY event.

This command completes an active background block operation synchronously. The ordering of this command’s return with the BLOCK_JOB_COMPLETED event is not defined. Note that if an I/O error occurs during the processing of this command: 1) the command itself will fail; 2) the error will be processed according to the rerror/werror arguments that were specified when starting the operation.

A cancelled or paused job cannot be completed.

Arguments
device: string
The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.
Returns
  • Nothing on success
  • If no background operation is active on this device, DeviceNotActive
Since

1.3

block-job-dismiss (Command)

For jobs that have already concluded, remove them from the block-job-query list. This command only needs to be run for jobs which were started with QEMU 2.12+ job lifetime management semantics.

This command will refuse to operate on any job that has not yet reached its terminal state, JOB_STATUS_CONCLUDED. For jobs that make use of the BLOCK_JOB_READY event, block-job-cancel or block-job-complete will still need to be used as appropriate.

Arguments
id: string
The job identifier.
Returns

Nothing on success

Since

2.12

block-job-finalize (Command)

Once a job that has manual=true reaches the pending state, it can be instructed to finalize any graph changes and do any necessary cleanup via this command. For jobs in a transaction, instructing one job to finalize will force ALL jobs in the transaction to finalize, so it is only necessary to instruct a single member job to finalize.

Arguments
id: string
The job identifier.
Returns

Nothing on success

Since

2.12

BlockdevDiscardOptions (Enum)

Determines how to handle discard requests.

Values
ignore
Ignore the request
unmap
Forward as an unmap request
Since

2.9

BlockdevDetectZeroesOptions (Enum)

Describes the operation mode for the automatic conversion of plain zero writes by the OS to driver specific optimized zero write commands.

Values
off
Disabled (default)
on
Enabled
unmap
Enabled and even try to unmap blocks if possible. This requires also that BlockdevDiscardOptions is set to unmap for this device.
Since

2.1

BlockdevAioOptions (Enum)

Selects the AIO backend to handle I/O requests

Values
threads
Use qemu’s thread pool
native
Use native AIO backend (only Linux and Windows)
io_uring (If: defined(CONFIG_LINUX_IO_URING))
Use linux io_uring (since 5.0)
Since

2.9

BlockdevCacheOptions (Object)

Includes cache-related options for block devices

Members
direct: boolean (optional)
enables use of O_DIRECT (bypass the host page cache; default: false)
no-flush: boolean (optional)
ignore any flush requests for the device (default: false)
Since

2.9

BlockdevDriver (Enum)

Drivers that are supported in block device operations.

Values
vxhs
Since 2.10
throttle
Since 2.11
nvme
Since 2.12
copy-on-read
Since 3.0
blklogwrites
Since 3.0
blkreplay
Since 4.2
compress
Since 5.0
blkdebug
Not documented
blkverify
Not documented
bochs
Not documented
cloop
Not documented
dmg
Not documented
file
Not documented
ftp
Not documented
ftps
Not documented
gluster
Not documented
host_cdrom
Not documented
host_device
Not documented
http
Not documented
https
Not documented
iscsi
Not documented
luks
Not documented
nbd
Not documented
nfs
Not documented
null-aio
Not documented
null-co
Not documented
parallels
Not documented
qcow
Not documented
qcow2
Not documented
qed
Not documented
quorum
Not documented
raw
Not documented
rbd
Not documented
replication (If: defined(CONFIG_REPLICATION))
Not documented
sheepdog
Not documented
ssh
Not documented
vdi
Not documented
vhdx
Not documented
vmdk
Not documented
vpc
Not documented
vvfat
Not documented
Since

2.9

BlockdevOptionsFile (Object)

Driver specific block device options for the file backend.

Members
filename: string
path to the image file
pr-manager: string (optional)
the id for the object that will handle persistent reservations for this device (default: none, forward the commands via SG_IO; since 2.11)
aio: BlockdevAioOptions (optional)
AIO backend (default: threads) (since: 2.8)
locking: OnOffAuto (optional)
whether to enable file locking. If set to ‘auto’, only enable when Open File Descriptor (OFD) locking API is available (default: auto, since 2.10)
drop-cache: boolean (optional) (If: defined(CONFIG_LINUX))
invalidate page cache during live migration. This prevents stale data on the migration destination with cache.direct=off. Currently only supported on Linux hosts. (default: on, since: 4.0)
x-check-cache-dropped: boolean (optional)
whether to check that page cache was dropped on live migration. May cause noticeable delays if the image file is large, do not use in production. (default: off) (since: 3.0)
Features
dynamic-auto-read-only
If present, enabled auto-read-only means that the driver will open the image read-only at first, dynamically reopen the image file read-write when the first writer is attached to the node and reopen read-only when the last writer is detached. This allows giving QEMU write permissions only on demand when an operation actually needs write access.
Since

2.9

BlockdevOptionsNull (Object)

Driver specific block device options for the null backend.

Members
size: int (optional)
size of the device in bytes.
latency-ns: int (optional)
emulated latency (in nanoseconds) in processing requests. Default to zero which completes requests immediately. (Since 2.4)
read-zeroes: boolean (optional)
if true, reads from the device produce zeroes; if false, the buffer is left unchanged. (default: false; since: 4.1)
Since

2.9

BlockdevOptionsNVMe (Object)

Driver specific block device options for the NVMe backend.

Members
device: string
PCI controller address of the NVMe device in format hhhh:bb:ss.f (host:bus:slot.function)
namespace: int
namespace number of the device, starting from 1.
Note that the PCI device must have been unbound from any host kernel driver before instructing QEMU to add the blockdev.
Since

2.12

BlockdevOptionsVVFAT (Object)

Driver specific block device options for the vvfat protocol.

Members
dir: string
directory to be exported as FAT image
fat-type: int (optional)
FAT type: 12, 16 or 32
floppy: boolean (optional)
whether to export a floppy image (true) or partitioned hard disk (false; default)
label: string (optional)
set the volume label, limited to 11 bytes. FAT16 and FAT32 traditionally have some restrictions on labels, which are ignored by most operating systems. Defaults to “QEMU VVFAT”. (since 2.4)
rw: boolean (optional)
whether to allow write operations (default: false)
Since

2.9

BlockdevOptionsGenericFormat (Object)

Driver specific block device options for image format that have no option besides their data source.

Members
file: BlockdevRef
reference to or definition of the data source block device
Since

2.9

BlockdevOptionsLUKS (Object)

Driver specific block device options for LUKS.

Members
key-secret: string (optional)
the ID of a QCryptoSecret object providing the decryption key (since 2.6). Mandatory except when doing a metadata-only probe of the image.
The members of BlockdevOptionsGenericFormat
Since

2.9

BlockdevOptionsGenericCOWFormat (Object)

Driver specific block device options for image format that have no option besides their data source and an optional backing file.

Members
backing: BlockdevRefOrNull (optional)
reference to or definition of the backing file block device, null disables the backing file entirely. Defaults to the backing file stored the image file.
The members of BlockdevOptionsGenericFormat
Since

2.9

Qcow2OverlapCheckMode (Enum)

General overlap check modes.

Values
none
Do not perform any checks
constant
Perform only checks which can be done in constant time and without reading anything from disk
cached
Perform only checks which can be done without reading anything from disk
all
Perform all available overlap checks
Since

2.9

Qcow2OverlapCheckFlags (Object)

Structure of flags for each metadata structure. Setting a field to ‘true’ makes qemu guard that structure against unintended overwriting. The default value is chosen according to the template given.

Members
template: Qcow2OverlapCheckMode (optional)
Specifies a template mode which can be adjusted using the other flags, defaults to ‘cached’
bitmap-directory: boolean (optional)
since 3.0
main-header: boolean (optional)
Not documented
active-l1: boolean (optional)
Not documented
active-l2: boolean (optional)
Not documented
refcount-table: boolean (optional)
Not documented
refcount-block: boolean (optional)
Not documented
snapshot-table: boolean (optional)
Not documented
inactive-l1: boolean (optional)
Not documented
inactive-l2: boolean (optional)
Not documented
Since

2.9

Qcow2OverlapChecks (Alternate)

Specifies which metadata structures should be guarded against unintended overwriting.

Members
flags: Qcow2OverlapCheckFlags
set of flags for separate specification of each metadata structure type
mode: Qcow2OverlapCheckMode
named mode which chooses a specific set of flags
Since

2.9

BlockdevQcowEncryptionFormat (Enum)

Values
aes
AES-CBC with plain64 initialization vectors
Since

2.10

BlockdevQcowEncryption (Object)

Members
format: BlockdevQcowEncryptionFormat
Not documented
The members of QCryptoBlockOptionsQCow when format is "aes"
Since

2.10

BlockdevOptionsQcow (Object)

Driver specific block device options for qcow.

Members
encrypt: BlockdevQcowEncryption (optional)
Image decryption options. Mandatory for encrypted images, except when doing a metadata-only probe of the image.
The members of BlockdevOptionsGenericCOWFormat
Since

2.10

BlockdevQcow2EncryptionFormat (Enum)

Values
aes
AES-CBC with plain64 initialization vectors
luks
Not documented
Since

2.10

BlockdevQcow2Encryption (Object)

Members
format: BlockdevQcow2EncryptionFormat
Not documented
The members of QCryptoBlockOptionsQCow when format is "aes"
The members of QCryptoBlockOptionsLUKS when format is "luks"
Since

2.10

BlockdevOptionsQcow2 (Object)

Driver specific block device options for qcow2.

Members
lazy-refcounts: boolean (optional)
whether to enable the lazy refcounts feature (default is taken from the image file)
pass-discard-request: boolean (optional)
whether discard requests to the qcow2 device should be forwarded to the data source
pass-discard-snapshot: boolean (optional)
whether discard requests for the data source should be issued when a snapshot operation (e.g. deleting a snapshot) frees clusters in the qcow2 file
pass-discard-other: boolean (optional)
whether discard requests for the data source should be issued on other occasions where a cluster gets freed
overlap-check: Qcow2OverlapChecks (optional)
which overlap checks to perform for writes to the image, defaults to ‘cached’ (since 2.2)
cache-size: int (optional)
the maximum total size of the L2 table and refcount block caches in bytes (since 2.2)
l2-cache-size: int (optional)
the maximum size of the L2 table cache in bytes (since 2.2)
l2-cache-entry-size: int (optional)
the size of each entry in the L2 cache in bytes. It must be a power of two between 512 and the cluster size. The default value is the cluster size (since 2.12)
refcount-cache-size: int (optional)
the maximum size of the refcount block cache in bytes (since 2.2)
cache-clean-interval: int (optional)
clean unused entries in the L2 and refcount caches. The interval is in seconds. The default value is 600 on supporting platforms, and 0 on other platforms. 0 disables this feature. (since 2.5)
encrypt: BlockdevQcow2Encryption (optional)
Image decryption options. Mandatory for encrypted images, except when doing a metadata-only probe of the image. (since 2.10)
data-file: BlockdevRef (optional)
reference to or definition of the external data file. This may only be specified for images that require an external data file. If it is not specified for such an image, the data file name is loaded from the image file. (since 4.0)
The members of BlockdevOptionsGenericCOWFormat
Since

2.9

SshHostKeyCheckMode (Enum)

Values
none
Don’t check the host key at all
hash
Compare the host key with a given hash
known_hosts
Check the host key against the known_hosts file
Since

2.12

SshHostKeyCheckHashType (Enum)

Values
md5
The given hash is an md5 hash
sha1
The given hash is an sha1 hash
Since

2.12

SshHostKeyHash (Object)

Members
type: SshHostKeyCheckHashType
The hash algorithm used for the hash
hash: string
The expected hash value
Since

2.12

SshHostKeyCheck (Object)

Members
mode: SshHostKeyCheckMode
Not documented
The members of SshHostKeyHash when mode is "hash"
Since

2.12

BlockdevOptionsSsh (Object)

Members
server: InetSocketAddress
host address
path: string
path to the image on the host
user: string (optional)
user as which to connect, defaults to current
local user name
host-key-check: SshHostKeyCheck (optional)
Defines how and what to check the host key against
(default: known_hosts)
Since

2.9

BlkdebugEvent (Enum)

Trigger events supported by blkdebug.

Values
l1_shrink_write_table
write zeros to the l1 table to shrink image. (since 2.11)
l1_shrink_free_l2_clusters
discard the l2 tables. (since 2.11)
cor_write
a write due to copy-on-read (since 2.11)
cluster_alloc_space
an allocation of file space for a cluster (since 4.1)
none
triggers once at creation of the blkdebug node (since 4.1)
l1_update
Not documented
l1_grow_alloc_table
Not documented
l1_grow_write_table
Not documented
l1_grow_activate_table
Not documented
l2_load
Not documented
l2_update
Not documented
l2_update_compressed
Not documented
l2_alloc_cow_read
Not documented
l2_alloc_write
Not documented
read_aio
Not documented
read_backing_aio
Not documented
read_compressed
Not documented
write_aio
Not documented
write_compressed
Not documented
vmstate_load
Not documented
vmstate_save
Not documented
cow_read
Not documented
cow_write
Not documented
reftable_load
Not documented
reftable_grow
Not documented
reftable_update
Not documented
refblock_load
Not documented
refblock_update
Not documented
refblock_update_part
Not documented
refblock_alloc
Not documented
refblock_alloc_hookup
Not documented
refblock_alloc_write
Not documented
refblock_alloc_write_blocks
Not documented
refblock_alloc_write_table
Not documented
refblock_alloc_switch_table
Not documented
cluster_alloc
Not documented
cluster_alloc_bytes
Not documented
cluster_free
Not documented
flush_to_os
Not documented
flush_to_disk
Not documented
pwritev_rmw_head
Not documented
pwritev_rmw_after_head
Not documented
pwritev_rmw_tail
Not documented
pwritev_rmw_after_tail
Not documented
pwritev
Not documented
pwritev_zero
Not documented
pwritev_done
Not documented
empty_image_prepare
Not documented
Since

2.9

BlkdebugIOType (Enum)

Kinds of I/O that blkdebug can inject errors in.

Values
read
.bdrv_co_preadv()
write
.bdrv_co_pwritev()
write-zeroes
.bdrv_co_pwrite_zeroes()
discard
.bdrv_co_pdiscard()
flush
.bdrv_co_flush_to_disk()
block-status
.bdrv_co_block_status()
Since

4.1

BlkdebugInjectErrorOptions (Object)

Describes a single error injection for blkdebug.

Members
event: BlkdebugEvent
trigger event
state: int (optional)
the state identifier blkdebug needs to be in to actually trigger the event; defaults to “any”
iotype: BlkdebugIOType (optional)
the type of I/O operations on which this error should be injected; defaults to “all read, write, write-zeroes, discard, and flush operations” (since: 4.1)
errno: int (optional)
error identifier (errno) to be returned; defaults to EIO
sector: int (optional)
specifies the sector index which has to be affected in order to actually trigger the event; defaults to “any sector”
once: boolean (optional)
disables further events after this one has been triggered; defaults to false
immediately: boolean (optional)
fail immediately; defaults to false
Since

2.9

BlkdebugSetStateOptions (Object)

Describes a single state-change event for blkdebug.

Members
event: BlkdebugEvent
trigger event
state: int (optional)
the current state identifier blkdebug needs to be in; defaults to “any”
new_state: int
the state identifier blkdebug is supposed to assume if this event is triggered
Since

2.9

BlockdevOptionsBlkdebug (Object)

Driver specific block device options for blkdebug.

Members
image: BlockdevRef
underlying raw block device (or image file)
config: string (optional)
filename of the configuration file
align: int (optional)
required alignment for requests in bytes, must be positive power of 2, or 0 for default
max-transfer: int (optional)
maximum size for I/O transfers in bytes, must be positive multiple of align and of the underlying file’s request alignment (but need not be a power of 2), or 0 for default (since 2.10)
opt-write-zero: int (optional)
preferred alignment for write zero requests in bytes, must be positive multiple of align and of the underlying file’s request alignment (but need not be a power of 2), or 0 for default (since 2.10)
max-write-zero: int (optional)
maximum size for write zero requests in bytes, must be positive multiple of align, of opt-write-zero, and of the underlying file’s request alignment (but need not be a power of 2), or 0 for default (since 2.10)
opt-discard: int (optional)
preferred alignment for discard requests in bytes, must be positive multiple of align and of the underlying file’s request alignment (but need not be a power of 2), or 0 for default (since 2.10)
max-discard: int (optional)
maximum size for discard requests in bytes, must be positive multiple of align, of opt-discard, and of the underlying file’s request alignment (but need not be a power of 2), or 0 for default (since 2.10)
inject-error: array of BlkdebugInjectErrorOptions (optional)
array of error injection descriptions
set-state: array of BlkdebugSetStateOptions (optional)
array of state-change descriptions
take-child-perms: array of BlockPermission (optional)
Permissions to take on image in addition to what is necessary anyway (which depends on how the blkdebug node is used). Defaults to none. (since 5.0)
unshare-child-perms: array of BlockPermission (optional)
Permissions not to share on image in addition to what cannot be shared anyway (which depends on how the blkdebug node is used). Defaults to none. (since 5.0)
Since

2.9

BlockdevOptionsBlklogwrites (Object)

Driver specific block device options for blklogwrites.

Members
file: BlockdevRef
block device
log: BlockdevRef
block device used to log writes to file
log-sector-size: int (optional)
sector size used in logging writes to file, determines granularity of offsets and sizes of writes (default: 512)
log-append: boolean (optional)
append to an existing log (default: false)
log-super-update-interval: int (optional)
interval of write requests after which the log super block is updated to disk (default: 4096)
Since

3.0

BlockdevOptionsBlkverify (Object)

Driver specific block device options for blkverify.

Members
test: BlockdevRef
block device to be tested
raw: BlockdevRef
raw image used for verification
Since

2.9

BlockdevOptionsBlkreplay (Object)

Driver specific block device options for blkreplay.

Members
image: BlockdevRef
disk image which should be controlled with blkreplay
Since

4.2

QuorumReadPattern (Enum)

An enumeration of quorum read patterns.

Values
quorum
read all the children and do a quorum vote on reads
fifo
read only from the first child that has not failed
Since

2.9

BlockdevOptionsQuorum (Object)

Driver specific block device options for Quorum

Members
blkverify: boolean (optional)
true if the driver must print content mismatch
set to false by default
children: array of BlockdevRef
the children block devices to use
vote-threshold: int
the vote limit under which a read will fail
rewrite-corrupted: boolean (optional)
rewrite corrupted data when quorum is reached (Since 2.1)
read-pattern: QuorumReadPattern (optional)
choose read pattern and set to quorum by default (Since 2.2)
Since

2.9

BlockdevOptionsGluster (Object)

Driver specific block device options for Gluster

Members
volume: string
name of gluster volume where VM image resides
path: string
absolute path to image file in gluster volume
server: array of SocketAddress
gluster servers description
debug: int (optional)
libgfapi log level (default ‘4’ which is Error) (Since 2.8)
logfile: string (optional)
libgfapi log file (default /dev/stderr) (Since 2.8)
Since

2.9

IscsiTransport (Enum)

An enumeration of libiscsi transport types

Values
tcp
Not documented
iser
Not documented
Since

2.9

IscsiHeaderDigest (Enum)

An enumeration of header digests supported by libiscsi

Values
crc32c
Not documented
none
Not documented
crc32c-none
Not documented
none-crc32c
Not documented
Since

2.9

BlockdevOptionsIscsi (Object)

Members
transport: IscsiTransport
The iscsi transport type
portal: string
The address of the iscsi portal
target: string
The target iqn name
lun: int (optional)
LUN to connect to. Defaults to 0.
user: string (optional)
User name to log in with. If omitted, no CHAP authentication is performed.
password-secret: string (optional)
The ID of a QCryptoSecret object providing the password for the login. This option is required if user is specified.
initiator-name: string (optional)
The iqn name we want to identify to the target as. If this option is not specified, an initiator name is generated automatically.
header-digest: IscsiHeaderDigest (optional)
The desired header digest. Defaults to none-crc32c.
timeout: int (optional)
Timeout in seconds after which a request will timeout. 0 means no timeout and is the default.
Driver specific block device options for iscsi
Since

2.9

RbdAuthMode (Enum)

Values
cephx
Not documented
none
Not documented
Since

3.0

BlockdevOptionsRbd (Object)

Members
pool: string
Ceph pool name.
image: string
Image name in the Ceph pool.
conf: string (optional)
path to Ceph configuration file. Values in the configuration file will be overridden by options specified via QAPI.
snapshot: string (optional)
Ceph snapshot name.
user: string (optional)
Ceph id name.
auth-client-required: array of RbdAuthMode (optional)
Acceptable authentication modes. This maps to Ceph configuration option “auth_client_required”. (Since 3.0)
key-secret: string (optional)
ID of a QCryptoSecret object providing a key for cephx authentication. This maps to Ceph configuration option “key”. (Since 3.0)
server: array of InetSocketAddressBase (optional)
Monitor host address and port. This maps to the “mon_host” Ceph option.
Since

2.9

BlockdevOptionsSheepdog (Object)

Driver specific block device options for sheepdog

Members
vdi: string
Virtual disk image name
server: SocketAddress
The Sheepdog server to connect to
snap-id: int (optional)
Snapshot ID
tag: string (optional)
Snapshot tag name
Only one of snap-id and tag may be present.
Since

2.9

ReplicationMode (Enum)

An enumeration of replication modes.

Values
primary
Primary mode, the vm’s state will be sent to secondary QEMU.
secondary
Secondary mode, receive the vm’s state from primary QEMU.
Since

2.9

If
defined(CONFIG_REPLICATION)

BlockdevOptionsReplication (Object)

Driver specific block device options for replication

Members
mode: ReplicationMode
the replication mode
top-id: string (optional)
In secondary mode, node name or device ID of the root node who owns the replication node chain. Must not be given in primary mode.
The members of BlockdevOptionsGenericFormat
Since

2.9

If
defined(CONFIG_REPLICATION)

NFSTransport (Enum)

An enumeration of NFS transport types

Values
inet
TCP transport
Since

2.9

NFSServer (Object)

Captures the address of the socket

Members
type: NFSTransport
transport type used for NFS (only TCP supported)
host: string
host address for NFS server
Since

2.9

BlockdevOptionsNfs (Object)

Driver specific block device option for NFS

Members
server: NFSServer
host address
path: string
path of the image on the host
user: int (optional)
UID value to use when talking to the server (defaults to 65534 on Windows and getuid() on unix)
group: int (optional)
GID value to use when talking to the server (defaults to 65534 on Windows and getgid() in unix)
tcp-syn-count: int (optional)
number of SYNs during the session establishment (defaults to libnfs default)
readahead-size: int (optional)
set the readahead size in bytes (defaults to libnfs default)
page-cache-size: int (optional)
set the pagecache size in bytes (defaults to libnfs default)
debug: int (optional)
set the NFS debug level (max 2) (defaults to libnfs default)
Since

2.9

BlockdevOptionsCurlBase (Object)

Driver specific block device options shared by all protocols supported by the curl backend.

Members
url: string
URL of the image file
readahead: int (optional)
Size of the read-ahead cache; must be a multiple of 512 (defaults to 256 kB)
timeout: int (optional)
Timeout for connections, in seconds (defaults to 5)
username: string (optional)
Username for authentication (defaults to none)
password-secret: string (optional)
ID of a QCryptoSecret object providing a password for authentication (defaults to no password)
proxy-username: string (optional)
Username for proxy authentication (defaults to none)
proxy-password-secret: string (optional)
ID of a QCryptoSecret object providing a password for proxy authentication (defaults to no password)
Since

2.9

BlockdevOptionsCurlHttp (Object)

Driver specific block device options for HTTP connections over the curl backend. URLs must start with “http://”.

Members
cookie: string (optional)
List of cookies to set; format is “name1=content1; name2=content2;” as explained by CURLOPT_COOKIE(3). Defaults to no cookies.
cookie-secret: string (optional)
ID of a QCryptoSecret object providing the cookie data in a secure way. See cookie for the format. (since 2.10)
The members of BlockdevOptionsCurlBase
Since

2.9

BlockdevOptionsCurlHttps (Object)

Driver specific block device options for HTTPS connections over the curl backend. URLs must start with “https://”.

Members
cookie: string (optional)
List of cookies to set; format is “name1=content1; name2=content2;” as explained by CURLOPT_COOKIE(3). Defaults to no cookies.
sslverify: boolean (optional)
Whether to verify the SSL certificate’s validity (defaults to true)
cookie-secret: string (optional)
ID of a QCryptoSecret object providing the cookie data in a secure way. See cookie for the format. (since 2.10)
The members of BlockdevOptionsCurlBase
Since

2.9

BlockdevOptionsCurlFtp (Object)

Driver specific block device options for FTP connections over the curl backend. URLs must start with “ftp://”.

Members
The members of BlockdevOptionsCurlBase
Since

2.9

BlockdevOptionsCurlFtps (Object)

Driver specific block device options for FTPS connections over the curl backend. URLs must start with “ftps://”.

Members
sslverify: boolean (optional)
Whether to verify the SSL certificate’s validity (defaults to true)
The members of BlockdevOptionsCurlBase
Since

2.9

BlockdevOptionsNbd (Object)

Driver specific block device options for NBD.

Members
server: SocketAddress
NBD server address
export: string (optional)
export name
tls-creds: string (optional)
TLS credentials ID
x-dirty-bitmap: string (optional)
A “qemu:dirty-bitmap:NAME” string to query in place of traditional “base:allocation” block status (see NBD_OPT_LIST_META_CONTEXT in the NBD protocol) (since 3.0)
reconnect-delay: int (optional)
On an unexpected disconnect, the nbd client tries to connect again until succeeding or encountering a serious error. During the first reconnect-delay seconds, all requests are paused and will be rerun on a successful reconnect. After that time, any delayed requests and all future requests before a successful reconnect will immediately fail. Default 0 (Since 4.2)
Since

2.9

BlockdevOptionsRaw (Object)

Driver specific block device options for the raw driver.

Members
offset: int (optional)
position where the block device starts
size: int (optional)
the assumed size of the device
The members of BlockdevOptionsGenericFormat
Since

2.9

BlockdevOptionsVxHS (Object)

Driver specific block device options for VxHS

Members
vdisk-id: string
UUID of VxHS volume
server: InetSocketAddressBase
vxhs server IP, port
tls-creds: string (optional)
TLS credentials ID
Since

2.10

BlockdevOptionsThrottle (Object)

Driver specific block device options for the throttle driver

Members
throttle-group: string
the name of the throttle-group object to use. It must already exist.
file: BlockdevRef
reference to or definition of the data source block device
Since

2.11

BlockdevOptions (Object)

Options for creating a block device. Many options are available for all block devices, independent of the block driver:

Members
driver: BlockdevDriver
block driver name
node-name: string (optional)
the node name of the new node (Since 2.0). This option is required on the top level of blockdev-add. Valid node names start with an alphabetic character and may contain only alphanumeric characters, ‘-‘, ‘.’ and ‘_’. Their maximum length is 31 characters.
discard: BlockdevDiscardOptions (optional)
discard-related options (default: ignore)
cache: BlockdevCacheOptions (optional)
cache-related options
read-only: boolean (optional)
whether the block device should be read-only (default: false). Note that some block drivers support only read-only access, either generally or in certain configurations. In this case, the default value does not work and the option must be specified explicitly.
auto-read-only: boolean (optional)
if true and read-only is false, QEMU may automatically decide not to open the image read-write as requested, but fall back to read-only instead (and switch between the modes later), e.g. depending on whether the image file is writable or whether a writing user is attached to the node (default: false, since 3.1)
detect-zeroes: BlockdevDetectZeroesOptions (optional)
detect and optimize zero writes (Since 2.1) (default: off)
force-share: boolean (optional)
force share all permission on added nodes. Requires read-only=true. (Since 2.10)
The members of BlockdevOptionsBlkdebug when driver is "blkdebug"
The members of BlockdevOptionsBlklogwrites when driver is "blklogwrites"
The members of BlockdevOptionsBlkverify when driver is "blkverify"
The members of BlockdevOptionsBlkreplay when driver is "blkreplay"
The members of BlockdevOptionsGenericFormat when driver is "bochs"
The members of BlockdevOptionsGenericFormat when driver is "cloop"
The members of BlockdevOptionsGenericFormat when driver is "compress"
The members of BlockdevOptionsGenericFormat when driver is "copy-on-read"
The members of BlockdevOptionsGenericFormat when driver is "dmg"
The members of BlockdevOptionsFile when driver is "file"
The members of BlockdevOptionsCurlFtp when driver is "ftp"
The members of BlockdevOptionsCurlFtps when driver is "ftps"
The members of BlockdevOptionsGluster when driver is "gluster"
The members of BlockdevOptionsFile when driver is "host_cdrom"
The members of BlockdevOptionsFile when driver is "host_device"
The members of BlockdevOptionsCurlHttp when driver is "http"
The members of BlockdevOptionsCurlHttps when driver is "https"
The members of BlockdevOptionsIscsi when driver is "iscsi"
The members of BlockdevOptionsLUKS when driver is "luks"
The members of BlockdevOptionsNbd when driver is "nbd"
The members of BlockdevOptionsNfs when driver is "nfs"
The members of BlockdevOptionsNull when driver is "null-aio"
The members of BlockdevOptionsNull when driver is "null-co"
The members of BlockdevOptionsNVMe when driver is "nvme"
The members of BlockdevOptionsGenericFormat when driver is "parallels"
The members of BlockdevOptionsQcow2 when driver is "qcow2"
The members of BlockdevOptionsQcow when driver is "qcow"
The members of BlockdevOptionsGenericCOWFormat when driver is "qed"
The members of BlockdevOptionsQuorum when driver is "quorum"
The members of BlockdevOptionsRaw when driver is "raw"
The members of BlockdevOptionsRbd when driver is "rbd"
The members of BlockdevOptionsReplication when driver is "replication" (If: defined(CONFIG_REPLICATION))
The members of BlockdevOptionsSheepdog when driver is "sheepdog"
The members of BlockdevOptionsSsh when driver is "ssh"
The members of BlockdevOptionsThrottle when driver is "throttle"
The members of BlockdevOptionsGenericFormat when driver is "vdi"
The members of BlockdevOptionsGenericFormat when driver is "vhdx"
The members of BlockdevOptionsGenericCOWFormat when driver is "vmdk"
The members of BlockdevOptionsGenericFormat when driver is "vpc"
The members of BlockdevOptionsVVFAT when driver is "vvfat"
The members of BlockdevOptionsVxHS when driver is "vxhs"
Remaining options are determined by the block driver.
Since

2.9

BlockdevRef (Alternate)

Reference to a block device.

Members
definition: BlockdevOptions
defines a new block device inline
reference: string
references the ID of an existing block device
Since

2.9

BlockdevRefOrNull (Alternate)

Reference to a block device.

Members
definition: BlockdevOptions
defines a new block device inline
reference: string
references the ID of an existing block device. An empty string means that no block device should be referenced. Deprecated; use null instead.
null: null
No block device should be referenced (since 2.10)
Since

2.9

blockdev-add (Command)

Creates a new block device. If the id option is given at the top level, a BlockBackend will be created; otherwise, node-name is mandatory at the top level and no BlockBackend will be created.

Arguments
The members of BlockdevOptions
Since

2.9

Example
1.
-> { "execute": "blockdev-add",
     "arguments": {
          "driver": "qcow2",
          "node-name": "test1",
          "file": {
              "driver": "file",
              "filename": "test.qcow2"
           }
      }
    }
<- { "return": {} }

2.
-> { "execute": "blockdev-add",
     "arguments": {
          "driver": "qcow2",
          "node-name": "node0",
          "discard": "unmap",
          "cache": {
             "direct": true
           },
           "file": {
             "driver": "file",
             "filename": "/tmp/test.qcow2"
           },
           "backing": {
              "driver": "raw",
              "file": {
                 "driver": "file",
                 "filename": "/dev/fdset/4"
               }
           }
       }
     }

<- { "return": {} }

x-blockdev-reopen (Command)

Reopens a block device using the given set of options. Any option not specified will be reset to its default value regardless of its previous status. If an option cannot be changed or a particular driver does not support reopening then the command will return an error.

The top-level node-name option (from BlockdevOptions) must be specified and is used to select the block device to be reopened. Other node-name options must be either omitted or set to the current name of the appropriate node. This command won’t change any node name and any attempt to do it will result in an error.

In the case of options that refer to child nodes, the behavior of this command depends on the value:

  1. A set of options (BlockdevOptions): the child is reopened with the specified set of options.
  2. A reference to the current child: the child is reopened using its existing set of options.
  3. A reference to a different node: the current child is replaced with the specified one.
  4. NULL: the current child (if any) is detached.

Options (1) and (2) are supported in all cases, but at the moment only backing allows replacing or detaching an existing child.

Unlike with blockdev-add, the backing option must always be present unless the node being reopened does not have a backing file and its image does not have a default backing file name as part of its metadata.

Arguments
The members of BlockdevOptions
Since

4.0

blockdev-del (Command)

Deletes a block device that has been added using blockdev-add. The command will fail if the node is attached to a device or is otherwise being used.

Arguments
node-name: string
Name of the graph node to delete.
Since

2.9

Example
-> { "execute": "blockdev-add",
     "arguments": {
          "driver": "qcow2",
          "node-name": "node0",
          "file": {
              "driver": "file",
              "filename": "test.qcow2"
          }
     }
   }
<- { "return": {} }

-> { "execute": "blockdev-del",
     "arguments": { "node-name": "node0" }
   }
<- { "return": {} }

BlockdevCreateOptionsFile (Object)

Driver specific image creation options for file.

Members
filename: string
Filename for the new image file
size: int
Size of the virtual disk in bytes
preallocation: PreallocMode (optional)
Preallocation mode for the new image (default: off; allowed values: off, falloc (if defined CONFIG_POSIX_FALLOCATE), full (if defined CONFIG_POSIX))
nocow: boolean (optional)
Turn off copy-on-write (valid only on btrfs; default: off)
Since

2.12

BlockdevCreateOptionsGluster (Object)

Driver specific image creation options for gluster.

Members
location: BlockdevOptionsGluster
Where to store the new image file
size: int
Size of the virtual disk in bytes
preallocation: PreallocMode (optional)
Preallocation mode for the new image (default: off; allowed values: off, falloc (if defined CONFIG_GLUSTERFS_FALLOCATE), full (if defined CONFIG_GLUSTERFS_ZEROFILL))
Since

2.12

BlockdevCreateOptionsLUKS (Object)

Driver specific image creation options for LUKS.

Members
file: BlockdevRef
Node to create the image format on
size: int
Size of the virtual disk in bytes
preallocation: PreallocMode (optional)
Preallocation mode for the new image (since: 4.2) (default: off; allowed values: off, metadata, falloc, full)
The members of QCryptoBlockCreateOptionsLUKS
Since

2.12

BlockdevCreateOptionsNfs (Object)

Driver specific image creation options for NFS.

Members
location: BlockdevOptionsNfs
Where to store the new image file
size: int
Size of the virtual disk in bytes
Since

2.12

BlockdevCreateOptionsParallels (Object)

Driver specific image creation options for parallels.

Members
file: BlockdevRef
Node to create the image format on
size: int
Size of the virtual disk in bytes
cluster-size: int (optional)
Cluster size in bytes (default: 1 MB)
Since

2.12

BlockdevCreateOptionsQcow (Object)

Driver specific image creation options for qcow.

Members
file: BlockdevRef
Node to create the image format on
size: int
Size of the virtual disk in bytes
backing-file: string (optional)
File name of the backing file if a backing file should be used
encrypt: QCryptoBlockCreateOptions (optional)
Encryption options if the image should be encrypted
Since

2.12

BlockdevQcow2Version (Enum)

Values
v2
The original QCOW2 format as introduced in qemu 0.10 (version 2)
v3
The extended QCOW2 format as introduced in qemu 1.1 (version 3)
Since

2.12

BlockdevCreateOptionsQcow2 (Object)

Driver specific image creation options for qcow2.

Members
file: BlockdevRef
Node to create the image format on
data-file: BlockdevRef (optional)
Node to use as an external data file in which all guest data is stored so that only metadata remains in the qcow2 file (since: 4.0)
data-file-raw: boolean (optional)
True if the external data file must stay valid as a standalone (read-only) raw image without looking at qcow2 metadata (default: false; since: 4.0)
size: int
Size of the virtual disk in bytes
version: BlockdevQcow2Version (optional)
Compatibility level (default: v3)
backing-file: string (optional)
File name of the backing file if a backing file should be used
backing-fmt: BlockdevDriver (optional)
Name of the block driver to use for the backing file
encrypt: QCryptoBlockCreateOptions (optional)
Encryption options if the image should be encrypted
cluster-size: int (optional)
qcow2 cluster size in bytes (default: 65536)
preallocation: PreallocMode (optional)
Preallocation mode for the new image (default: off; allowed values: off, falloc, full, metadata)
lazy-refcounts: boolean (optional)
True if refcounts may be updated lazily (default: off)
refcount-bits: int (optional)
Width of reference counts in bits (default: 16)
Since

2.12

BlockdevCreateOptionsQed (Object)

Driver specific image creation options for qed.

Members
file: BlockdevRef
Node to create the image format on
size: int
Size of the virtual disk in bytes
backing-file: string (optional)
File name of the backing file if a backing file should be used
backing-fmt: BlockdevDriver (optional)
Name of the block driver to use for the backing file
cluster-size: int (optional)
Cluster size in bytes (default: 65536)
table-size: int (optional)
L1/L2 table size (in clusters)
Since

2.12

BlockdevCreateOptionsRbd (Object)

Driver specific image creation options for rbd/Ceph.

Members
location: BlockdevOptionsRbd
Where to store the new image file. This location cannot point to a snapshot.
size: int
Size of the virtual disk in bytes
cluster-size: int (optional)
RBD object size
Since

2.12

BlockdevVmdkSubformat (Enum)

Subformat options for VMDK images

Values
monolithicSparse
Single file image with sparse cluster allocation
monolithicFlat
Single flat data image and a descriptor file
twoGbMaxExtentSparse
Data is split into 2GB (per virtual LBA) sparse extent files, in addition to a descriptor file
twoGbMaxExtentFlat
Data is split into 2GB (per virtual LBA) flat extent
files, in addition to a descriptor file
streamOptimized
Single file image sparse cluster allocation, optimized
for streaming over network.
Since

4.0

BlockdevVmdkAdapterType (Enum)

Adapter type info for VMDK images

Values
ide
Not documented
buslogic
Not documented
lsilogic
Not documented
legacyESX
Not documented
Since

4.0

BlockdevCreateOptionsVmdk (Object)

Driver specific image creation options for VMDK.

Members
file: BlockdevRef
Where to store the new image file. This refers to the image file for monolithcSparse and streamOptimized format, or the descriptor file for other formats.
size: int
Size of the virtual disk in bytes
extents: array of BlockdevRef (optional)
Where to store the data extents. Required for monolithcFlat, twoGbMaxExtentSparse and twoGbMaxExtentFlat formats. For monolithicFlat, only one entry is required; for twoGbMaxExtent* formats, the number of entries required is calculated as extent_number = virtual_size / 2GB. Providing more extents than will be used is an error.
subformat: BlockdevVmdkSubformat (optional)
The subformat of the VMDK image. Default: “monolithicSparse”.
backing-file: string (optional)
The path of backing file. Default: no backing file is used.
adapter-type: BlockdevVmdkAdapterType (optional)
The adapter type used to fill in the descriptor. Default: ide.
hwversion: string (optional)
Hardware version. The meaningful options are “4” or “6”. Default: “4”.
zeroed-grain: boolean (optional)
Whether to enable zeroed-grain feature for sparse subformats. Default: false.
Since

4.0

SheepdogRedundancyType (Enum)

Values
full
Create a fully replicated vdi with x copies
erasure-coded
Create an erasure coded vdi with x data strips and y parity strips
Since

2.12

SheepdogRedundancyFull (Object)

Members
copies: int
Number of copies to use (between 1 and 31)
Since

2.12

SheepdogRedundancyErasureCoded (Object)

Members
data-strips: int
Number of data strips to use (one of {2,4,8,16})
parity-strips: int
Number of parity strips to use (between 1 and 15)
Since

2.12

SheepdogRedundancy (Object)

Members
type: SheepdogRedundancyType
Not documented
The members of SheepdogRedundancyFull when type is "full"
The members of SheepdogRedundancyErasureCoded when type is "erasure-coded"
Since

2.12

BlockdevCreateOptionsSheepdog (Object)

Driver specific image creation options for Sheepdog.

Members
location: BlockdevOptionsSheepdog
Where to store the new image file
size: int
Size of the virtual disk in bytes
backing-file: string (optional)
File name of a base image
preallocation: PreallocMode (optional)
Preallocation mode for the new image (default: off; allowed values: off, full)
redundancy: SheepdogRedundancy (optional)
Redundancy of the image
object-size: int (optional)
Object size of the image
Since

2.12

BlockdevCreateOptionsSsh (Object)

Driver specific image creation options for SSH.

Members
location: BlockdevOptionsSsh
Where to store the new image file
size: int
Size of the virtual disk in bytes
Since

2.12

BlockdevCreateOptionsVdi (Object)

Driver specific image creation options for VDI.

Members
file: BlockdevRef
Node to create the image format on
size: int
Size of the virtual disk in bytes
preallocation: PreallocMode (optional)
Preallocation mode for the new image (default: off; allowed values: off, metadata)
Since

2.12

BlockdevVhdxSubformat (Enum)

Values
dynamic
Growing image file
fixed
Preallocated fixed-size image file
Since

2.12

BlockdevCreateOptionsVhdx (Object)

Driver specific image creation options for vhdx.

Members
file: BlockdevRef
Node to create the image format on
size: int
Size of the virtual disk in bytes
log-size: int (optional)
Log size in bytes, must be a multiple of 1 MB (default: 1 MB)
block-size: int (optional)
Block size in bytes, must be a multiple of 1 MB and not larger than 256 MB (default: automatically choose a block size depending on the image size)
subformat: BlockdevVhdxSubformat (optional)
vhdx subformat (default: dynamic)
block-state-zero: boolean (optional)
Force use of payload blocks of type ‘ZERO’. Non-standard, but default. Do not set to ‘off’ when using ‘qemu-img convert’ with subformat=dynamic.
Since

2.12

BlockdevVpcSubformat (Enum)

Values
dynamic
Growing image file
fixed
Preallocated fixed-size image file
Since

2.12

BlockdevCreateOptionsVpc (Object)

Driver specific image creation options for vpc (VHD).

Members
file: BlockdevRef
Node to create the image format on
size: int
Size of the virtual disk in bytes
subformat: BlockdevVpcSubformat (optional)
vhdx subformat (default: dynamic)
force-size: boolean (optional)
Force use of the exact byte size instead of rounding to the next size that can be represented in CHS geometry (default: false)
Since

2.12

BlockdevCreateOptions (Object)

Options for creating an image format on a given node.

Members
driver: BlockdevDriver
block driver to create the image format
The members of BlockdevCreateOptionsFile when driver is "file"
The members of BlockdevCreateOptionsGluster when driver is "gluster"
The members of BlockdevCreateOptionsLUKS when driver is "luks"
The members of BlockdevCreateOptionsNfs when driver is "nfs"
The members of BlockdevCreateOptionsParallels when driver is "parallels"
The members of BlockdevCreateOptionsQcow when driver is "qcow"
The members of BlockdevCreateOptionsQcow2 when driver is "qcow2"
The members of BlockdevCreateOptionsQed when driver is "qed"
The members of BlockdevCreateOptionsRbd when driver is "rbd"
The members of BlockdevCreateOptionsSheepdog when driver is "sheepdog"
The members of BlockdevCreateOptionsSsh when driver is "ssh"
The members of BlockdevCreateOptionsVdi when driver is "vdi"
The members of BlockdevCreateOptionsVhdx when driver is "vhdx"
The members of BlockdevCreateOptionsVmdk when driver is "vmdk"
The members of BlockdevCreateOptionsVpc when driver is "vpc"
Since

2.12

blockdev-create (Command)

Starts a job to create an image format on a given node. The job is automatically finalized, but a manual job-dismiss is required.

Arguments
job-id: string
Identifier for the newly created job.
options: BlockdevCreateOptions
Options for the image creation.
Since

3.0

blockdev-open-tray (Command)

Opens a block device’s tray. If there is a block driver state tree inserted as a medium, it will become inaccessible to the guest (but it will remain associated to the block device, so closing the tray will make it accessible again).

If the tray was already open before, this will be a no-op.

Once the tray opens, a DEVICE_TRAY_MOVED event is emitted. There are cases in which no such event will be generated, these include:

  • if the guest has locked the tray, force is false and the guest does not respond to the eject request
  • if the BlockBackend denoted by device does not have a guest device attached to it
  • if the guest device does not have an actual tray
Arguments
device: string (optional)
Block device name (deprecated, use id instead)
id: string (optional)
The name or QOM path of the guest device (since: 2.8)
force: boolean (optional)
if false (the default), an eject request will be sent to the guest if it has locked the tray (and the tray will not be opened immediately); if true, the tray will be opened regardless of whether it is locked
Since

2.5

Example
-> { "execute": "blockdev-open-tray",
     "arguments": { "id": "ide0-1-0" } }

<- { "timestamp": { "seconds": 1418751016,
                    "microseconds": 716996 },
     "event": "DEVICE_TRAY_MOVED",
     "data": { "device": "ide1-cd0",
               "id": "ide0-1-0",
               "tray-open": true } }

<- { "return": {} }

blockdev-close-tray (Command)

Closes a block device’s tray. If there is a block driver state tree associated with the block device (which is currently ejected), that tree will be loaded as the medium.

If the tray was already closed before, this will be a no-op.

Arguments
device: string (optional)
Block device name (deprecated, use id instead)
id: string (optional)
The name or QOM path of the guest device (since: 2.8)
Since

2.5

Example
-> { "execute": "blockdev-close-tray",
     "arguments": { "id": "ide0-1-0" } }

<- { "timestamp": { "seconds": 1418751345,
                    "microseconds": 272147 },
     "event": "DEVICE_TRAY_MOVED",
     "data": { "device": "ide1-cd0",
               "id": "ide0-1-0",
               "tray-open": false } }

<- { "return": {} }

blockdev-remove-medium (Command)

Removes a medium (a block driver state tree) from a block device. That block device’s tray must currently be open (unless there is no attached guest device).

If the tray is open and there is no medium inserted, this will be a no-op.

Arguments
id: string
The name or QOM path of the guest device
Since

2.12

Example
-> { "execute": "blockdev-remove-medium",
     "arguments": { "id": "ide0-1-0" } }

<- { "error": { "class": "GenericError",
                "desc": "Tray of device 'ide0-1-0' is not open" } }

-> { "execute": "blockdev-open-tray",
     "arguments": { "id": "ide0-1-0" } }

<- { "timestamp": { "seconds": 1418751627,
                    "microseconds": 549958 },
     "event": "DEVICE_TRAY_MOVED",
     "data": { "device": "ide1-cd0",
               "id": "ide0-1-0",
               "tray-open": true } }

<- { "return": {} }

-> { "execute": "blockdev-remove-medium",
     "arguments": { "id": "ide0-1-0" } }

<- { "return": {} }

blockdev-insert-medium (Command)

Inserts a medium (a block driver state tree) into a block device. That block device’s tray must currently be open (unless there is no attached guest device) and there must be no medium inserted already.

Arguments
id: string
The name or QOM path of the guest device
node-name: string
name of a node in the block driver state graph
Since

2.12

Example
-> { "execute": "blockdev-add",
     "arguments": {
         "node-name": "node0",
         "driver": "raw",
         "file": { "driver": "file",
                   "filename": "fedora.iso" } } }
<- { "return": {} }

-> { "execute": "blockdev-insert-medium",
     "arguments": { "id": "ide0-1-0",
                    "node-name": "node0" } }

<- { "return": {} }

BlockdevChangeReadOnlyMode (Enum)

Specifies the new read-only mode of a block device subject to the blockdev-change-medium command.

Values
retain
Retains the current read-only mode
read-only
Makes the device read-only
read-write
Makes the device writable
Since

2.3

blockdev-change-medium (Command)

Changes the medium inserted into a block device by ejecting the current medium and loading a new image file which is inserted as the new medium (this command combines blockdev-open-tray, blockdev-remove-medium, blockdev-insert-medium and blockdev-close-tray).

Arguments
device: string (optional)
Block device name (deprecated, use id instead)
id: string (optional)
The name or QOM path of the guest device (since: 2.8)
filename: string
filename of the new image to be loaded
format: string (optional)
format to open the new image with (defaults to the probed format)
read-only-mode: BlockdevChangeReadOnlyMode (optional)
change the read-only mode of the device; defaults to ‘retain’
Since

2.5

Examples
1. Change a removable medium

-> { "execute": "blockdev-change-medium",
     "arguments": { "id": "ide0-1-0",
                    "filename": "/srv/images/Fedora-12-x86_64-DVD.iso",
                    "format": "raw" } }
<- { "return": {} }

2. Load a read-only medium into a writable drive

-> { "execute": "blockdev-change-medium",
     "arguments": { "id": "floppyA",
                    "filename": "/srv/images/ro.img",
                    "format": "raw",
                    "read-only-mode": "retain" } }

<- { "error":
     { "class": "GenericError",
       "desc": "Could not open '/srv/images/ro.img': Permission denied" } }

-> { "execute": "blockdev-change-medium",
     "arguments": { "id": "floppyA",
                    "filename": "/srv/images/ro.img",
                    "format": "raw",
                    "read-only-mode": "read-only" } }

<- { "return": {} }

BlockErrorAction (Enum)

An enumeration of action that has been taken when a DISK I/O occurs

Values
ignore
error has been ignored
report
error has been reported to the device
stop
error caused VM to be stopped
Since

2.1

BLOCK_IMAGE_CORRUPTED (Event)

Emitted when a disk image is being marked corrupt. The image can be identified by its device or node name. The ‘device’ field is always present for compatibility reasons, but it can be empty (“”) if the image does not have a device name associated.

Arguments
device: string
device name. This is always present for compatibility reasons, but it can be empty (“”) if the image does not have a device name associated.
node-name: string (optional)
node name (Since: 2.4)
msg: string
informative message for human consumption, such as the kind of corruption being detected. It should not be parsed by machine as it is not guaranteed to be stable
offset: int (optional)
if the corruption resulted from an image access, this is the host’s access offset into the image
size: int (optional)
if the corruption resulted from an image access, this is the access size
fatal: boolean
if set, the image is marked corrupt and therefore unusable after this event and must be repaired (Since 2.2; before, every BLOCK_IMAGE_CORRUPTED event was fatal)
Note

If action is “stop”, a STOP event will eventually follow the BLOCK_IO_ERROR event.

Example
<- { "event": "BLOCK_IMAGE_CORRUPTED",
     "data": { "device": "ide0-hd0", "node-name": "node0",
               "msg": "Prevented active L1 table overwrite", "offset": 196608,
               "size": 65536 },
     "timestamp": { "seconds": 1378126126, "microseconds": 966463 } }
Since

1.7

BLOCK_IO_ERROR (Event)

Emitted when a disk I/O error occurs

Arguments
device: string
device name. This is always present for compatibility reasons, but it can be empty (“”) if the image does not have a device name associated.
node-name: string (optional)
node name. Note that errors may be reported for the root node that is directly attached to a guest device rather than for the node where the error occurred. The node name is not present if the drive is empty. (Since: 2.8)
operation: IoOperationType
I/O operation
action: BlockErrorAction
action that has been taken
nospace: boolean (optional)
true if I/O error was caused due to a no-space condition. This key is only present if query-block’s io-status is present, please see query-block documentation for more information (since: 2.2)
reason: string
human readable string describing the error cause. (This field is a debugging aid for humans, it should not be parsed by applications) (since: 2.2)
Note

If action is “stop”, a STOP event will eventually follow the BLOCK_IO_ERROR event

Since

0.13.0

Example
<- { "event": "BLOCK_IO_ERROR",
     "data": { "device": "ide0-hd1",
               "node-name": "#block212",
               "operation": "write",
               "action": "stop" },
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }

BLOCK_JOB_COMPLETED (Event)

Emitted when a block job has completed

Arguments
type: JobType
job type
device: string
The job identifier. Originally the device name but other values are allowed since QEMU 2.7
len: int
maximum progress value
offset: int
current progress value. On success this is equal to len. On failure this is less than len
speed: int
rate limit, bytes per second
error: string (optional)
error message. Only present on failure. This field contains a human-readable error message. There are no semantics other than that streaming has failed and clients should not try to interpret the error string
Since

1.1

Example
<- { "event": "BLOCK_JOB_COMPLETED",
     "data": { "type": "stream", "device": "virtio-disk0",
               "len": 10737418240, "offset": 10737418240,
               "speed": 0 },
     "timestamp": { "seconds": 1267061043, "microseconds": 959568 } }

BLOCK_JOB_CANCELLED (Event)

Emitted when a block job has been cancelled

Arguments
type: JobType
job type
device: string
The job identifier. Originally the device name but other values are allowed since QEMU 2.7
len: int
maximum progress value
offset: int
current progress value. On success this is equal to len. On failure this is less than len
speed: int
rate limit, bytes per second
Since

1.1

Example
<- { "event": "BLOCK_JOB_CANCELLED",
     "data": { "type": "stream", "device": "virtio-disk0",
               "len": 10737418240, "offset": 134217728,
               "speed": 0 },
     "timestamp": { "seconds": 1267061043, "microseconds": 959568 } }

BLOCK_JOB_ERROR (Event)

Emitted when a block job encounters an error

Arguments
device: string
The job identifier. Originally the device name but other values are allowed since QEMU 2.7
operation: IoOperationType
I/O operation
action: BlockErrorAction
action that has been taken
Since

1.3

Example
<- { "event": "BLOCK_JOB_ERROR",
     "data": { "device": "ide0-hd1",
               "operation": "write",
               "action": "stop" },
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }

BLOCK_JOB_READY (Event)

Emitted when a block job is ready to complete

Arguments
type: JobType
job type
device: string
The job identifier. Originally the device name but other values are allowed since QEMU 2.7
len: int
maximum progress value
offset: int
current progress value. On success this is equal to len. On failure this is less than len
speed: int
rate limit, bytes per second
Note

The “ready to complete” status is always reset by a BLOCK_JOB_ERROR event

Since

1.3

Example
<- { "event": "BLOCK_JOB_READY",
     "data": { "device": "drive0", "type": "mirror", "speed": 0,
               "len": 2097152, "offset": 2097152 }
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }

BLOCK_JOB_PENDING (Event)

Emitted when a block job is awaiting explicit authorization to finalize graph changes via block-job-finalize. If this job is part of a transaction, it will not emit this event until the transaction has converged first.

Arguments
type: JobType
job type
id: string
The job identifier.
Since

2.12

Example
<- { "event": "BLOCK_JOB_WAITING",
     "data": { "device": "drive0", "type": "mirror" },
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }

PreallocMode (Enum)

Preallocation mode of QEMU image file

Values
off
no preallocation
metadata
preallocate only for metadata
falloc
like full preallocation but allocate disk space by posix_fallocate() rather than writing data.
full
preallocate all data by writing it to the device to ensure disk space is really available. This data may or may not be zero, depending on the image format and storage. full preallocation also sets up metadata correctly.
Since

2.2

BLOCK_WRITE_THRESHOLD (Event)

Emitted when writes on block device reaches or exceeds the configured write threshold. For thin-provisioned devices, this means the device should be extended to avoid pausing for disk exhaustion. The event is one shot. Once triggered, it needs to be re-registered with another block-set-write-threshold command.

Arguments
node-name: string
graph node name on which the threshold was exceeded.
amount-exceeded: int
amount of data which exceeded the threshold, in bytes.
write-threshold: int
last configured threshold, in bytes.
Since

2.3

block-set-write-threshold (Command)

Change the write threshold for a block drive. An event will be delivered if a write to this block drive crosses the configured threshold. The threshold is an offset, thus must be non-negative. Default is no write threshold. Setting the threshold to zero disables it.

This is useful to transparently resize thin-provisioned drives without the guest OS noticing.

Arguments
node-name: string
graph node name on which the threshold must be set.
write-threshold: int
configured threshold for the block device, bytes. Use 0 to disable the threshold.
Since

2.3

Example
-> { "execute": "block-set-write-threshold",
     "arguments": { "node-name": "mydev",
                    "write-threshold": 17179869184 } }
<- { "return": {} }

x-blockdev-change (Command)

Dynamically reconfigure the block driver state graph. It can be used to add, remove, insert or replace a graph node. Currently only the Quorum driver implements this feature to add or remove its child. This is useful to fix a broken quorum child.

If node is specified, it will be inserted under parent. child may not be specified in this case. If both parent and child are specified but node is not, child will be detached from parent.

Arguments
parent: string
the id or name of the parent node.
child: string (optional)
the name of a child under the given parent node.
node: string (optional)
the name of the node that will be added.
Note

this command is experimental, and its API is not stable. It does not support all kinds of operations, all kinds of children, nor all block drivers.

FIXME Removing children from a quorum node means introducing gaps in the child indices. This cannot be represented in the ‘children’ list of BlockdevOptionsQuorum, as returned by .bdrv_refresh_filename().

Warning: The data in a new quorum child MUST be consistent with that of the rest of the array.

Since

2.7

Example
1. Add a new node to a quorum
-> { "execute": "blockdev-add",
     "arguments": {
         "driver": "raw",
         "node-name": "new_node",
         "file": { "driver": "file",
                   "filename": "test.raw" } } }
<- { "return": {} }
-> { "execute": "x-blockdev-change",
     "arguments": { "parent": "disk1",
                    "node": "new_node" } }
<- { "return": {} }

2. Delete a quorum's node
-> { "execute": "x-blockdev-change",
     "arguments": { "parent": "disk1",
                    "child": "children.1" } }
<- { "return": {} }

x-blockdev-set-iothread (Command)

Move node and its children into the iothread. If iothread is null then move node and its children into the main loop.

The node must not be attached to a BlockBackend.

Arguments
node-name: string
the name of the block driver node
iothread: StrOrNull
the name of the IOThread object or null for the main loop
force: boolean (optional)
true if the node and its children should be moved when a BlockBackend is already attached
Note

this command is experimental and intended for test cases that need control over IOThreads only.

Since

2.12

Example
1. Move a node into an IOThread
-> { "execute": "x-blockdev-set-iothread",
     "arguments": { "node-name": "disk1",
                    "iothread": "iothread0" } }
<- { "return": {} }

2. Move a node into the main loop
-> { "execute": "x-blockdev-set-iothread",
     "arguments": { "node-name": "disk1",
                    "iothread": null } }
<- { "return": {} }

Additional block stuff (VM related)

BiosAtaTranslation (Enum)

Policy that BIOS should use to interpret cylinder/head/sector addresses. Note that Bochs BIOS and SeaBIOS will not actually translate logical CHS to physical; instead, they will use logical block addressing.

Values
auto
If cylinder/heads/sizes are passed, choose between none and LBA depending on the size of the disk. If they are not passed, choose none if QEMU can guess that the disk had 16 or fewer heads, large if QEMU can guess that the disk had 131072 or fewer tracks across all heads (i.e. cylinders*heads<131072), otherwise LBA.
none
The physical disk geometry is equal to the logical geometry.
lba
Assume 63 sectors per track and one of 16, 32, 64, 128 or 255 heads (if fewer than 255 are enough to cover the whole disk with 1024 cylinders/head). The number of cylinders/head is then computed based on the number of sectors and heads.
large
The number of cylinders per head is scaled down to 1024 by correspondingly scaling up the number of heads.
rechs
Same as large, but first convert a 16-head geometry to 15-head, by proportionally scaling up the number of cylinders/head.
Since

2.0

FloppyDriveType (Enum)

Type of Floppy drive to be emulated by the Floppy Disk Controller.

Values
144
1.44MB 3.5” drive
288
2.88MB 3.5” drive
120
1.2MB 5.25” drive
none
No drive connected
auto
Automatically determined by inserted media at boot
Since

2.6

BlockdevSnapshotInternal (Object)

Members
device: string
the device name or node-name of a root node to generate the snapshot from
name: string
the name of the internal snapshot to be created
Notes

In transaction, if name is empty, or any snapshot matching name exists, the operation will fail. Only some image formats support it, for example, qcow2, rbd, and sheepdog.

Since

1.7

PRManagerInfo (Object)

Information about a persistent reservation manager

Members
id: string
the identifier of the persistent reservation manager
connected: boolean
true if the persistent reservation manager is connected to the underlying storage or helper
Since

3.0

query-pr-managers (Command)

Returns a list of information about each persistent reservation manager.

Returns

a list of PRManagerInfo for each persistent reservation manager

Since

3.0

blockdev-snapshot-internal-sync (Command)

Synchronously take an internal snapshot of a block device, when the format of the image used supports it. If the name is an empty string, or a snapshot with name already exists, the operation will fail.

For the arguments, see the documentation of BlockdevSnapshotInternal.

Returns
  • nothing on success
  • If device is not a valid block device, GenericError
  • If any snapshot matching name exists, or name is empty, GenericError
  • If the format of the image used does not support it, BlockFormatFeatureNotSupported
Since

1.7

Example
-> { "execute": "blockdev-snapshot-internal-sync",
     "arguments": { "device": "ide-hd0",
                    "name": "snapshot0" }
   }
<- { "return": {} }

blockdev-snapshot-delete-internal-sync (Command)

Synchronously delete an internal snapshot of a block device, when the format of the image used support it. The snapshot is identified by name or id or both. One of the name or id is required. Return SnapshotInfo for the successfully deleted snapshot.

Arguments
device: string
the device name or node-name of a root node to delete the snapshot from
id: string (optional)
optional the snapshot’s ID to be deleted
name: string (optional)
optional the snapshot’s name to be deleted
Returns
  • SnapshotInfo on success
  • If device is not a valid block device, GenericError
  • If snapshot not found, GenericError
  • If the format of the image used does not support it, BlockFormatFeatureNotSupported
  • If id and name are both not specified, GenericError
Since

1.7

Example
-> { "execute": "blockdev-snapshot-delete-internal-sync",
     "arguments": { "device": "ide-hd0",
                    "name": "snapshot0" }
   }
<- { "return": {
                   "id": "1",
                   "name": "snapshot0",
                   "vm-state-size": 0,
                   "date-sec": 1000012,
                   "date-nsec": 10,
                   "vm-clock-sec": 100,
                   "vm-clock-nsec": 20
     }
   }

eject (Command)

Ejects a device from a removable drive.

Arguments
device: string (optional)
Block device name (deprecated, use id instead)
id: string (optional)
The name or QOM path of the guest device (since: 2.8)
force: boolean (optional)
If true, eject regardless of whether the drive is locked. If not specified, the default value is false.
Returns
  • Nothing on success
  • If device is not a valid block device, DeviceNotFound
Notes

Ejecting a device with no media results in success

Since

0.14.0

Example
-> { "execute": "eject", "arguments": { "id": "ide1-0-1" } }
<- { "return": {} }

nbd-server-start (Command)

Start an NBD server listening on the given host and port. Block devices can then be exported using nbd-server-add. The NBD server will present them as named exports; for example, another QEMU instance could refer to them as “nbd:HOST:PORT:exportname=NAME”.

Arguments
addr: SocketAddressLegacy
Address on which to listen.
tls-creds: string (optional)
ID of the TLS credentials object (since 2.6).
tls-authz: string (optional)
ID of the QAuthZ authorization object used to validate the client’s x509 distinguished name. This object is is only resolved at time of use, so can be deleted and recreated on the fly while the NBD server is active. If missing, it will default to denying access (since 4.0).
Returns

error if the server is already running.

Since

1.3.0

nbd-server-add (Command)

Export a block node to QEMU’s embedded NBD server.

Arguments
device: string
The device name or node name of the node to be exported
name: string (optional)
Export name. If unspecified, the device parameter is used as the export name. (Since 2.12)
description: string (optional)
Free-form description of the export, up to 4096 bytes. (Since 5.0)
writable: boolean (optional)
Whether clients should be able to write to the device via the NBD connection (default false).
bitmap: string (optional)
Also export the dirty bitmap reachable from device, so the NBD client can use NBD_OPT_SET_META_CONTEXT with “qemu:dirty-bitmap:NAME” to inspect the bitmap. (since 4.0)
Returns

error if the server is not running, or export with the same name already exists.

Since

1.3.0

NbdServerRemoveMode (Enum)

Mode for removing an NBD export.

Values
safe
Remove export if there are no existing connections, fail otherwise.
hard
Drop all connections immediately and remove export.

Potential additional modes to be added in the future:

hide: Just hide export from new clients, leave existing connections as is. Remove export after all clients are disconnected.

soft: Hide export from new clients, answer with ESHUTDOWN for all further requests from existing clients.

Since

2.12

nbd-server-remove (Command)

Remove NBD export by name.

Arguments
name: string
Export name.
mode: NbdServerRemoveMode (optional)
Mode of command operation. See NbdServerRemoveMode description. Default is ‘safe’.
Returns
error if
  • the server is not running
  • export is not found
  • mode is ‘safe’ and there are existing connections
Since

2.12

nbd-server-stop (Command)

Stop QEMU’s embedded NBD server, and unregister all devices previously added via nbd-server-add.

Since

1.3.0

DEVICE_TRAY_MOVED (Event)

Emitted whenever the tray of a removable device is moved by the guest or by HMP/QMP commands

Arguments
device: string
Block device name. This is always present for compatibility reasons, but it can be empty (“”) if the image does not have a device name associated.
id: string
The name or QOM path of the guest device (since 2.8)
tray-open: boolean
true if the tray has been opened or false if it has been closed
Since

1.1

Example
<- { "event": "DEVICE_TRAY_MOVED",
     "data": { "device": "ide1-cd0",
               "id": "/machine/unattached/device[22]",
               "tray-open": true
     },
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }

PR_MANAGER_STATUS_CHANGED (Event)

Emitted whenever the connected status of a persistent reservation manager changes.

Arguments
id: string
The id of the PR manager object
connected: boolean
true if the PR manager is connected to a backend
Since

3.0

Example
<- { "event": "PR_MANAGER_STATUS_CHANGED",
     "data": { "id": "pr-helper0",
               "connected": true
     },
     "timestamp": { "seconds": 1519840375, "microseconds": 450486 } }

QuorumOpType (Enum)

An enumeration of the quorum operation types

Values
read
read operation
write
write operation
flush
flush operation
Since

2.6

QUORUM_FAILURE (Event)

Emitted by the Quorum block driver if it fails to establish a quorum

Arguments
reference: string
device name if defined else node name
sector-num: int
number of the first sector of the failed read operation
sectors-count: int
failed read operation sector count
Note

This event is rate-limited.

Since

2.0

Example
<- { "event": "QUORUM_FAILURE",
     "data": { "reference": "usr1", "sector-num": 345435, "sectors-count": 5 },
     "timestamp": { "seconds": 1344522075, "microseconds": 745528 } }

QUORUM_REPORT_BAD (Event)

Emitted to report a corruption of a Quorum file

Arguments
type: QuorumOpType
quorum operation type (Since 2.6)
error: string (optional)
error message. Only present on failure. This field contains a human-readable error message. There are no semantics other than that the block layer reported an error and clients should not try to interpret the error string.
node-name: string
the graph node name of the block driver state
sector-num: int
number of the first sector of the failed read operation
sectors-count: int
failed read operation sector count
Note

This event is rate-limited.

Since

2.0

Example
1. Read operation

{ "event": "QUORUM_REPORT_BAD",
     "data": { "node-name": "node0", "sector-num": 345435, "sectors-count": 5,
               "type": "read" },
     "timestamp": { "seconds": 1344522075, "microseconds": 745528 } }

2. Flush operation

{ "event": "QUORUM_REPORT_BAD",
     "data": { "node-name": "node0", "sector-num": 0, "sectors-count": 2097120,
               "type": "flush", "error": "Broken pipe" },
     "timestamp": { "seconds": 1456406829, "microseconds": 291763 } }

Character devices

ChardevInfo (Object)

Information about a character device.

Members

label: string
the label of the character device
filename: string
the filename of the character device
frontend-open: boolean
shows whether the frontend device attached to this backend (eg. with the chardev=… option) is in open or closed state (since 2.1)

Notes

filename is encoded using the QEMU command line character device encoding. See the QEMU man page for details.

Since

0.14.0

query-chardev (Command)

Returns information about current character devices.

Returns

a list of ChardevInfo

Since

0.14.0

Example

-> { "execute": "query-chardev" }
<- {
      "return": [
         {
            "label": "charchannel0",
            "filename": "unix:/var/lib/libvirt/qemu/seabios.rhel6.agent,server",
            "frontend-open": false
         },
         {
            "label": "charmonitor",
            "filename": "unix:/var/lib/libvirt/qemu/seabios.rhel6.monitor,server",
            "frontend-open": true
         },
         {
            "label": "charserial0",
            "filename": "pty:/dev/pts/2",
            "frontend-open": true
         }
      ]
   }

ChardevBackendInfo (Object)

Information about a character device backend

Members

name: string
The backend name

Since

2.0

query-chardev-backends (Command)

Returns information about character device backends.

Returns

a list of ChardevBackendInfo

Since

2.0

Example

-> { "execute": "query-chardev-backends" }
<- {
      "return":[
         {
            "name":"udp"
         },
         {
            "name":"tcp"
         },
         {
            "name":"unix"
         },
         {
            "name":"spiceport"
         }
      ]
   }

DataFormat (Enum)

An enumeration of data format.

Values

utf8
Data is a UTF-8 string (RFC 3629)
base64
Data is Base64 encoded binary (RFC 3548)

Since

1.4

ringbuf-write (Command)

Write to a ring buffer character device.

Arguments

device: string
the ring buffer character device name
data: string
data to write
format: DataFormat (optional)

data encoding (default ‘utf8’).

  • base64: data must be base64 encoded text. Its binary decoding gets written.
  • utf8: data’s UTF-8 encoding is written
  • data itself is always Unicode regardless of format, like any other string.

Returns

Nothing on success

Since

1.4

Example

-> { "execute": "ringbuf-write",
     "arguments": { "device": "foo",
                    "data": "abcdefgh",
                    "format": "utf8" } }
<- { "return": {} }

ringbuf-read (Command)

Read from a ring buffer character device.

Arguments

device: string
the ring buffer character device name
size: int
how many bytes to read at most
format: DataFormat (optional)

data encoding (default ‘utf8’).

  • base64: the data read is returned in base64 encoding.
  • utf8: the data read is interpreted as UTF-8. Bug: can screw up when the buffer contains invalid UTF-8 sequences, NUL characters, after the ring buffer lost data, and when reading stops because the size limit is reached.
  • The return value is always Unicode regardless of format, like any other string.

Returns

data read from the device

Since

1.4

Example

-> { "execute": "ringbuf-read",
     "arguments": { "device": "foo",
                    "size": 1000,
                    "format": "utf8" } }
<- { "return": "abcdefgh" }

ChardevCommon (Object)

Configuration shared across all chardev backends

Members

logfile: string (optional)
The name of a logfile to save output
logappend: boolean (optional)
true to append instead of truncate (default to false to truncate)

Since

2.6

ChardevFile (Object)

Configuration info for file chardevs.

Members

in: string (optional)
The name of the input file
out: string
The name of the output file
append: boolean (optional)
Open the file in append mode (default false to truncate) (Since 2.6)
The members of ChardevCommon

Since

1.4

ChardevHostdev (Object)

Configuration info for device and pipe chardevs.

Members

device: string
The name of the special file for the device, i.e. /dev/ttyS0 on Unix or COM1: on Windows
The members of ChardevCommon

Since

1.4

ChardevSocket (Object)

Configuration info for (stream) socket chardevs.

Members

addr: SocketAddressLegacy
socket address to listen on (server=true) or connect to (server=false)
tls-creds: string (optional)
the ID of the TLS credentials object (since 2.6)
tls-authz: string (optional)
the ID of the QAuthZ authorization object against which the client’s x509 distinguished name will be validated. This object is only resolved at time of use, so can be deleted and recreated on the fly while the chardev server is active. If missing, it will default to denying access (since 4.0)
server: boolean (optional)
create server socket (default: true)
wait: boolean (optional)
wait for incoming connection on server sockets (default: false).
nodelay: boolean (optional)
set TCP_NODELAY socket option (default: false)
telnet: boolean (optional)
enable telnet protocol on server sockets (default: false)
tn3270: boolean (optional)
enable tn3270 protocol on server sockets (default: false) (Since: 2.10)
websocket: boolean (optional)
enable websocket protocol on server sockets (default: false) (Since: 3.1)
reconnect: int (optional)
For a client socket, if a socket is disconnected, then attempt a reconnect after the given number of seconds. Setting this to zero disables this function. (default: 0) (Since: 2.2)
The members of ChardevCommon

Since

1.4

ChardevUdp (Object)

Configuration info for datagram socket chardevs.

Members

remote: SocketAddressLegacy
remote address
local: SocketAddressLegacy (optional)
local address
The members of ChardevCommon

Since

1.5

ChardevMux (Object)

Configuration info for mux chardevs.

Members

chardev: string
name of the base chardev.
The members of ChardevCommon

Since

1.5

ChardevStdio (Object)

Configuration info for stdio chardevs.

Members

signal: boolean (optional)
Allow signals (such as SIGINT triggered by ^C) be delivered to qemu. Default: true in -nographic mode, false otherwise.
The members of ChardevCommon

Since

1.5

ChardevSpiceChannel (Object)

Configuration info for spice vm channel chardevs.

Members

type: string
kind of channel (for example vdagent).
The members of ChardevCommon

Since

1.5

If

defined(CONFIG_SPICE)

ChardevSpicePort (Object)

Configuration info for spice port chardevs.

Members

fqdn: string
name of the channel (see docs/spice-port-fqdn.txt)
The members of ChardevCommon

Since

1.5

If

defined(CONFIG_SPICE)

ChardevVC (Object)

Configuration info for virtual console chardevs.

Members

width: int (optional)
console width, in pixels
height: int (optional)
console height, in pixels
cols: int (optional)
console width, in chars
rows: int (optional)
console height, in chars
The members of ChardevCommon

Since

1.5

ChardevRingbuf (Object)

Configuration info for ring buffer chardevs.

Members

size: int (optional)
ring buffer size, must be power of two, default is 65536
The members of ChardevCommon

Since

1.5

ChardevBackend (Object)

Configuration info for the new chardev backend.

Members

type
One of file, serial, parallel, pipe, socket, udp, pty, null, mux, msmouse, wctablet, braille, testdev, stdio, console, spicevmc, spiceport, vc, ringbuf, memory
data: ChardevFile when type is "file"
data: ChardevHostdev when type is "serial"
data: ChardevHostdev when type is "parallel"
data: ChardevHostdev when type is "pipe"
data: ChardevSocket when type is "socket"
data: ChardevUdp when type is "udp"
data: ChardevCommon when type is "pty"
data: ChardevCommon when type is "null"
data: ChardevMux when type is "mux"
data: ChardevCommon when type is "msmouse"
data: ChardevCommon when type is "wctablet"
data: ChardevCommon when type is "braille"
data: ChardevCommon when type is "testdev"
data: ChardevStdio when type is "stdio"
data: ChardevCommon when type is "console"
data: ChardevSpiceChannel when type is "spicevmc" (If: defined(CONFIG_SPICE))
data: ChardevSpicePort when type is "spiceport" (If: defined(CONFIG_SPICE))
data: ChardevVC when type is "vc"
data: ChardevRingbuf when type is "ringbuf"
data: ChardevRingbuf when type is "memory"

Since

1.4 (testdev since 2.2, wctablet since 2.9)

ChardevReturn (Object)

Return info about the chardev backend just created.

Members

pty: string (optional)
name of the slave pseudoterminal device, present if and only if a chardev of type ‘pty’ was created

Since

1.4

chardev-add (Command)

Add a character device backend

Arguments

id: string
the chardev’s ID, must be unique
backend: ChardevBackend
backend type and parameters

Returns

ChardevReturn.

Since

1.4

Example

-> { "execute" : "chardev-add",
     "arguments" : { "id" : "foo",
                     "backend" : { "type" : "null", "data" : {} } } }
<- { "return": {} }

-> { "execute" : "chardev-add",
     "arguments" : { "id" : "bar",
                     "backend" : { "type" : "file",
                                   "data" : { "out" : "/tmp/bar.log" } } } }
<- { "return": {} }

-> { "execute" : "chardev-add",
     "arguments" : { "id" : "baz",
                     "backend" : { "type" : "pty", "data" : {} } } }
<- { "return": { "pty" : "/dev/pty/42" } }

chardev-change (Command)

Change a character device backend

Arguments

id: string
the chardev’s ID, must exist
backend: ChardevBackend
new backend type and parameters

Returns

ChardevReturn.

Since

2.10

Example

-> { "execute" : "chardev-change",
     "arguments" : { "id" : "baz",
                     "backend" : { "type" : "pty", "data" : {} } } }
<- { "return": { "pty" : "/dev/pty/42" } }

-> {"execute" : "chardev-change",
    "arguments" : {
        "id" : "charchannel2",
        "backend" : {
            "type" : "socket",
            "data" : {
                "addr" : {
                    "type" : "unix" ,
                    "data" : {
                        "path" : "/tmp/charchannel2.socket"
                    }
                 },
                 "server" : true,
                 "wait" : false }}}}
<- {"return": {}}

chardev-remove (Command)

Remove a character device backend

Arguments

id: string
the chardev’s ID, must exist and not be in use

Returns

Nothing on success

Since

1.4

Example

-> { "execute": "chardev-remove", "arguments": { "id" : "foo" } }
<- { "return": {} }

chardev-send-break (Command)

Send a break to a character device

Arguments

id: string
the chardev’s ID, must exist

Returns

Nothing on success

Since

2.10

Example

-> { "execute": "chardev-send-break", "arguments": { "id" : "foo" } }
<- { "return": {} }

VSERPORT_CHANGE (Event)

Emitted when the guest opens or closes a virtio-serial port.

Arguments

id: string
device identifier of the virtio-serial port
open: boolean
true if the guest has opened the virtio-serial port

Since

2.1

Example

<- { "event": "VSERPORT_CHANGE",
     "data": { "id": "channel0", "open": true },
     "timestamp": { "seconds": 1401385907, "microseconds": 422329 } }

Dump guest memory

DumpGuestMemoryFormat (Enum)

An enumeration of guest-memory-dump’s format.

Values

elf
elf format
kdump-zlib
kdump-compressed format with zlib-compressed
kdump-lzo
kdump-compressed format with lzo-compressed
kdump-snappy
kdump-compressed format with snappy-compressed
win-dmp
Windows full crashdump format, can be used instead of ELF converting (since 2.13)

Since

2.0

dump-guest-memory (Command)

Dump guest’s memory to vmcore. It is a synchronous operation that can take very long depending on the amount of guest memory.

Arguments

paging: boolean

if true, do paging to get guest’s memory mapping. This allows using gdb to process the core file.

IMPORTANT: this option can make QEMU allocate several gigabytes of RAM. This can happen for a large guest, or a malicious guest pretending to be large.

Also, paging=true has the following limitations:

  1. The guest may be in a catastrophic state or can have corrupted memory, which cannot be trusted
  2. The guest can be in real-mode even if paging is enabled. For example, the guest uses ACPI to sleep, and ACPI sleep state goes in real-mode
  3. Currently only supported on i386 and x86_64.
protocol: string

the filename or file descriptor of the vmcore. The supported protocols are:

  1. file: the protocol starts with “file:”, and the following string is the file’s path.
  2. fd: the protocol starts with “fd:”, and the following string is the fd’s name.
detach: boolean (optional)
if true, QMP will return immediately rather than waiting for the dump to finish. The user can track progress using “query-dump”. (since 2.6).
begin: int (optional)
if specified, the starting physical address.
length: int (optional)
if specified, the memory size, in bytes. If you don’t want to dump all guest’s memory, please specify the start begin and length
format: DumpGuestMemoryFormat (optional)
if specified, the format of guest memory dump. But non-elf format is conflict with paging and filter, ie. paging, begin and length is not allowed to be specified with non-elf format at the same time (since 2.0)

Note

All boolean arguments default to false

Returns

nothing on success

Since

1.2

Example

-> { "execute": "dump-guest-memory",
     "arguments": { "protocol": "fd:dump" } }
<- { "return": {} }

DumpStatus (Enum)

Describe the status of a long-running background guest memory dump.

Values

none
no dump-guest-memory has started yet.
active
there is one dump running in background.
completed
the last dump has finished successfully.
failed
the last dump has failed.

Since

2.6

DumpQueryResult (Object)

The result format for ‘query-dump’.

Members

status: DumpStatus
enum of DumpStatus, which shows current dump status
completed: int
bytes written in latest dump (uncompressed)
total: int
total bytes to be written in latest dump (uncompressed)

Since

2.6

query-dump (Command)

Query latest dump status.

Returns

A DumpStatus object showing the dump status.

Since

2.6

Example

-> { "execute": "query-dump" }
<- { "return": { "status": "active", "completed": 1024000,
                 "total": 2048000 } }

DUMP_COMPLETED (Event)

Emitted when background dump has completed

Arguments

result: DumpQueryResult
final dump status
error: string (optional)
human-readable error string that provides hint on why dump failed. Only presents on failure. The user should not try to interpret the error string.

Since

2.6

Example

{ "event": "DUMP_COMPLETED",
  "data": {"result": {"total": 1090650112, "status": "completed",
                      "completed": 1090650112} } }

DumpGuestMemoryCapability (Object)

A list of the available formats for dump-guest-memory

Members

formats: array of DumpGuestMemoryFormat
Not documented

Since

2.0

query-dump-guest-memory-capability (Command)

Returns the available formats for dump-guest-memory

Returns

A DumpGuestMemoryCapability object listing available formats for
dump-guest-memory

Since

2.0

Example

-> { "execute": "query-dump-guest-memory-capability" }
<- { "return": { "formats":
                 ["elf", "kdump-zlib", "kdump-lzo", "kdump-snappy"] }

Net devices

set_link (Command)

Sets the link status of a virtual network adapter.

Arguments

name: string
the device name of the virtual network adapter
up: boolean
true to set the link status to be up

Returns

Nothing on success If name is not a valid network device, DeviceNotFound

Since

0.14.0

Notes

Not all network adapters support setting link status. This command will succeed even if the network adapter does not support link status notification.

Example

-> { "execute": "set_link",
     "arguments": { "name": "e1000.0", "up": false } }
<- { "return": {} }

netdev_add (Command)

Add a network backend.

Arguments

type: string
the type of network backend. Possible values are listed in NetClientDriver (excluding ‘none’ and ‘nic’)
id: string
the name of the new network backend
Additional arguments depend on the type.

TODO

This command effectively bypasses QAPI completely due to its “additional arguments” business. It shouldn’t have been added to the schema in this form. It should be qapified properly, or replaced by a properly qapified command.

Since

0.14.0

Returns

Nothing on success If type is not a valid network backend, DeviceNotFound

Example

-> { "execute": "netdev_add",
     "arguments": { "type": "user", "id": "netdev1",
                    "dnssearch": "example.org" } }
<- { "return": {} }

netdev_del (Command)

Remove a network backend.

Arguments

id: string
the name of the network backend to remove

Returns

Nothing on success If id is not a valid network backend, DeviceNotFound

Since

0.14.0

Example

-> { "execute": "netdev_del", "arguments": { "id": "netdev1" } }
<- { "return": {} }

NetLegacyNicOptions (Object)

Create a new Network Interface Card.

Members

netdev: string (optional)
id of -netdev to connect to
macaddr: string (optional)
MAC address
model: string (optional)
device model (e1000, rtl8139, virtio etc.)
addr: string (optional)
PCI device address
vectors: int (optional)
number of MSI-x vectors, 0 to disable MSI-X

Since

1.2

NetdevUserOptions (Object)

Use the user mode network stack which requires no administrator privilege to run.

Members

hostname: string (optional)
client hostname reported by the builtin DHCP server
restrict: boolean (optional)
isolate the guest from the host
ipv4: boolean (optional)
whether to support IPv4, default true for enabled (since 2.6)
ipv6: boolean (optional)
whether to support IPv6, default true for enabled (since 2.6)
ip: string (optional)
legacy parameter, use net= instead
net: string (optional)
IP network address that the guest will see, in the form addr[/netmask] The netmask is optional, and can be either in the form a.b.c.d or as a number of valid top-most bits. Default is 10.0.2.0/24.
host: string (optional)
guest-visible address of the host
tftp: string (optional)
root directory of the built-in TFTP server
bootfile: string (optional)
BOOTP filename, for use with tftp=
dhcpstart: string (optional)
the first of the 16 IPs the built-in DHCP server can assign
dns: string (optional)
guest-visible address of the virtual nameserver
dnssearch: array of String (optional)
list of DNS suffixes to search, passed as DHCP option to the guest
domainname: string (optional)
guest-visible domain name of the virtual nameserver (since 3.0)
ipv6-prefix: string (optional)
IPv6 network prefix (default is fec0::) (since 2.6). The network prefix is given in the usual hexadecimal IPv6 address notation.
ipv6-prefixlen: int (optional)
IPv6 network prefix length (default is 64) (since 2.6)
ipv6-host: string (optional)
guest-visible IPv6 address of the host (since 2.6)
ipv6-dns: string (optional)
guest-visible IPv6 address of the virtual nameserver (since 2.6)
smb: string (optional)
root directory of the built-in SMB server
smbserver: string (optional)
IP address of the built-in SMB server
hostfwd: array of String (optional)
redirect incoming TCP or UDP host connections to guest endpoints
guestfwd: array of String (optional)
forward guest TCP connections
tftp-server-name: string (optional)
RFC2132 “TFTP server name” string (Since 3.1)

Since

1.2

NetdevTapOptions (Object)

Used to configure a host TAP network interface backend.

Members

ifname: string (optional)
interface name
fd: string (optional)
file descriptor of an already opened tap
fds: string (optional)
multiple file descriptors of already opened multiqueue capable tap
script: string (optional)
script to initialize the interface
downscript: string (optional)
script to shut down the interface
br: string (optional)
bridge name (since 2.8)
helper: string (optional)
command to execute to configure bridge
sndbuf: int (optional)
send buffer limit. Understands [TGMKkb] suffixes.
vnet_hdr: boolean (optional)
enable the IFF_VNET_HDR flag on the tap interface
vhost: boolean (optional)
enable vhost-net network accelerator
vhostfd: string (optional)
file descriptor of an already opened vhost net device
vhostfds: string (optional)
file descriptors of multiple already opened vhost net devices
vhostforce: boolean (optional)
vhost on for non-MSIX virtio guests
queues: int (optional)
number of queues to be created for multiqueue capable tap
poll-us: int (optional)
maximum number of microseconds that could be spent on busy polling for tap (since 2.7)

Since

1.2

NetdevSocketOptions (Object)

Socket netdevs are used to establish a network connection to another QEMU virtual machine via a TCP socket.

Members

fd: string (optional)
file descriptor of an already opened socket
listen: string (optional)
port number, and optional hostname, to listen on
connect: string (optional)
port number, and optional hostname, to connect to
mcast: string (optional)
UDP multicast address and port number
localaddr: string (optional)
source address and port for multicast and udp packets
udp: string (optional)
UDP unicast address and port number

Since

1.2

NetdevL2TPv3Options (Object)

Configure an Ethernet over L2TPv3 tunnel.

Members

src: string
source address
dst: string
destination address
srcport: string (optional)
source port - mandatory for udp, optional for ip
dstport: string (optional)
destination port - mandatory for udp, optional for ip
ipv6: boolean (optional)
force the use of ipv6
udp: boolean (optional)
use the udp version of l2tpv3 encapsulation
cookie64: boolean (optional)
use 64 bit coookies
counter: boolean (optional)
have sequence counter
pincounter: boolean (optional)
pin sequence counter to zero - workaround for buggy implementations or networks with packet reorder
txcookie: int (optional)
32 or 64 bit transmit cookie
rxcookie: int (optional)
32 or 64 bit receive cookie
txsession: int
32 bit transmit session
rxsession: int (optional)
32 bit receive session - if not specified set to the same value as transmit
offset: int (optional)
additional offset - allows the insertion of additional application-specific data before the packet payload

Since

2.1

NetdevVdeOptions (Object)

Connect to a vde switch running on the host.

Members

sock: string (optional)
socket path
port: int (optional)
port number
group: string (optional)
group owner of socket
mode: int (optional)
permissions for socket

Since

1.2

NetdevBridgeOptions (Object)

Connect a host TAP network interface to a host bridge device.

Members

br: string (optional)
bridge name
helper: string (optional)
command to execute to configure bridge

Since

1.2

NetdevHubPortOptions (Object)

Connect two or more net clients through a software hub.

Members

hubid: int
hub identifier number
netdev: string (optional)
used to connect hub to a netdev instead of a device (since 2.12)

Since

1.2

NetdevNetmapOptions (Object)

Connect a client to a netmap-enabled NIC or to a VALE switch port

Members

ifname: string
Either the name of an existing network interface supported by netmap, or the name of a VALE port (created on the fly). A VALE port name is in the form ‘valeXXX:YYY’, where XXX and YYY are non-negative integers. XXX identifies a switch and YYY identifies a port of the switch. VALE ports having the same XXX are therefore connected to the same switch.
devname: string (optional)
path of the netmap device (default: ‘/dev/netmap’).

Since

2.0

NetdevVhostUserOptions (Object)

Vhost-user network backend

Members

chardev: string
name of a unix socket chardev
vhostforce: boolean (optional)
vhost on for non-MSIX virtio guests (default: false).
queues: int (optional)
number of queues to be created for multiqueue vhost-user (default: 1) (Since 2.5)

Since

2.1

NetClientDriver (Enum)

Available netdev drivers.

Values

none
Not documented
nic
Not documented
user
Not documented
tap
Not documented
l2tpv3
Not documented
socket
Not documented
vde
Not documented
bridge
Not documented
hubport
Not documented
netmap
Not documented
vhost-user
Not documented

Since

2.7

Netdev (Object)

Captures the configuration of a network device.

Members

id: string
identifier for monitor commands.
type: NetClientDriver
Specify the driver used for interpreting remaining arguments.
The members of NetLegacyNicOptions when type is "nic"
The members of NetdevUserOptions when type is "user"
The members of NetdevTapOptions when type is "tap"
The members of NetdevL2TPv3Options when type is "l2tpv3"
The members of NetdevSocketOptions when type is "socket"
The members of NetdevVdeOptions when type is "vde"
The members of NetdevBridgeOptions when type is "bridge"
The members of NetdevHubPortOptions when type is "hubport"
The members of NetdevNetmapOptions when type is "netmap"
The members of NetdevVhostUserOptions when type is "vhost-user"

Since

1.2

‘l2tpv3’ - since 2.1

NetLegacy (Object)

Captures the configuration of a network device; legacy.

Members

id: string (optional)
identifier for monitor commands
name: string (optional)
identifier for monitor commands, ignored if id is present
opts: NetLegacyOptions
device type specific properties (legacy)

Since

1.2

NetLegacyOptionsType (Enum)

Values

none
Not documented
nic
Not documented
user
Not documented
tap
Not documented
l2tpv3
Not documented
socket
Not documented
vde
Not documented
bridge
Not documented
netmap
Not documented
vhost-user
Not documented

Since

1.2

NetLegacyOptions (Object)

Like Netdev, but for use only by the legacy command line options

Members

type: NetLegacyOptionsType
Not documented
The members of NetLegacyNicOptions when type is "nic"
The members of NetdevUserOptions when type is "user"
The members of NetdevTapOptions when type is "tap"
The members of NetdevL2TPv3Options when type is "l2tpv3"
The members of NetdevSocketOptions when type is "socket"
The members of NetdevVdeOptions when type is "vde"
The members of NetdevBridgeOptions when type is "bridge"
The members of NetdevNetmapOptions when type is "netmap"
The members of NetdevVhostUserOptions when type is "vhost-user"

Since

1.2

NetFilterDirection (Enum)

Indicates whether a netfilter is attached to a netdev’s transmit queue or receive queue or both.

Values

all
the filter is attached both to the receive and the transmit queue of the netdev (default).
rx
the filter is attached to the receive queue of the netdev, where it will receive packets sent to the netdev.
tx
the filter is attached to the transmit queue of the netdev, where it will receive packets sent by the netdev.

Since

2.5

RxState (Enum)

Packets receiving state

Values

normal
filter assigned packets according to the mac-table
none
don’t receive any assigned packet
all
receive all assigned packets

Since

1.6

RxFilterInfo (Object)

Rx-filter information for a NIC.

Members

name: string
net client name
promiscuous: boolean
whether promiscuous mode is enabled
multicast: RxState
multicast receive state
unicast: RxState
unicast receive state
vlan: RxState
vlan receive state (Since 2.0)
broadcast-allowed: boolean
whether to receive broadcast
multicast-overflow: boolean
multicast table is overflowed or not
unicast-overflow: boolean
unicast table is overflowed or not
main-mac: string
the main macaddr string
vlan-table: array of int
a list of active vlan id
unicast-table: array of string
a list of unicast macaddr string
multicast-table: array of string
a list of multicast macaddr string

Since

1.6

query-rx-filter (Command)

Return rx-filter information for all NICs (or for the given NIC).

Arguments

name: string (optional)
net client name

Returns

list of RxFilterInfo for all NICs (or for the given NIC). Returns an error if the given name doesn’t exist, or given NIC doesn’t support rx-filter querying, or given net client isn’t a NIC.

Since

1.6

Example

-> { "execute": "query-rx-filter", "arguments": { "name": "vnet0" } }
<- { "return": [
        {
            "promiscuous": true,
            "name": "vnet0",
            "main-mac": "52:54:00:12:34:56",
            "unicast": "normal",
            "vlan": "normal",
            "vlan-table": [
                4,
                0
            ],
            "unicast-table": [
            ],
            "multicast": "normal",
            "multicast-overflow": false,
            "unicast-overflow": false,
            "multicast-table": [
                "01:00:5e:00:00:01",
                "33:33:00:00:00:01",
                "33:33:ff:12:34:56"
            ],
            "broadcast-allowed": false
        }
      ]
   }

NIC_RX_FILTER_CHANGED (Event)

Emitted once until the ‘query-rx-filter’ command is executed, the first event will always be emitted

Arguments

name: string (optional)
net client name
path: string
device path

Since

1.6

Example

<- { "event": "NIC_RX_FILTER_CHANGED",
     "data": { "name": "vnet0",
               "path": "/machine/peripheral/vnet0/virtio-backend" },
     "timestamp": { "seconds": 1368697518, "microseconds": 326866 } }
   }

AnnounceParameters (Object)

Parameters for self-announce timers

Members

initial: int
Initial delay (in ms) before sending the first GARP/RARP announcement
max: int
Maximum delay (in ms) between GARP/RARP announcement packets
rounds: int
Number of self-announcement attempts
step: int
Delay increase (in ms) after each self-announcement attempt
interfaces: array of string (optional)
An optional list of interface names, which restricts the announcement to the listed interfaces. (Since 4.1)
id: string (optional)
A name to be used to identify an instance of announce-timers and to allow it to modified later. Not for use as part of the migration parameters. (Since 4.1)

Since

4.0

announce-self (Command)

Trigger generation of broadcast RARP frames to update network switches. This can be useful when network bonds fail-over the active slave.

Arguments

The members of AnnounceParameters

Example

-> { "execute": "announce-self",
     "arguments": {
         "initial": 50, "max": 550, "rounds": 10, "step": 50,
         "interfaces": ["vn2", "vn3"], "id": "bob" } }
<- { "return": {} }

Since

4.0

FAILOVER_NEGOTIATED (Event)

Emitted when VIRTIO_NET_F_STANDBY was enabled during feature negotiation. Failover primary devices which were hidden (not hotplugged when requested) before will now be hotplugged by the virtio-net standby device.

device-id: QEMU device id of the unplugged device

Arguments

device-id: string
Not documented

Since

4.2

Example

<- { "event": "FAILOVER_NEGOTIATED",
     "data": "net1" }

RDMA device

RDMA_GID_STATUS_CHANGED (Event)

Emitted when guest driver adds/deletes GID to/from device

Arguments

netdev: string
RoCE Network Device name
gid-status: boolean
Add or delete indication
subnet-prefix: int
Subnet Prefix
interface-id: int
Not documented
interface-id : Interface ID

Since

4.0

Example

<- {"timestamp": {"seconds": 1541579657, "microseconds": 986760},
    "event": "RDMA_GID_STATUS_CHANGED",
    "data":
        {"netdev": "bridge0",
        "interface-id": 15880512517475447892,
        "gid-status": true,
        "subnet-prefix": 33022}}

Rocker switch device

RockerSwitch (Object)

Rocker switch information.

Members

name: string
switch name
id: int
switch ID
ports: int
number of front-panel ports

Since

2.4

query-rocker (Command)

Return rocker switch information.

Arguments

name: string
Not documented

Returns

Rocker information

Since

2.4

Example

-> { "execute": "query-rocker", "arguments": { "name": "sw1" } }
<- { "return": {"name": "sw1", "ports": 2, "id": 1327446905938}}

RockerPortDuplex (Enum)

An eumeration of port duplex states.

Values

half
half duplex
full
full duplex

Since

2.4

RockerPortAutoneg (Enum)

An eumeration of port autoneg states.

Values

off
autoneg is off
on
autoneg is on

Since

2.4

RockerPort (Object)

Rocker switch port information.

Members

name: string
port name
enabled: boolean
port is enabled for I/O
link-up: boolean
physical link is UP on port
speed: int
port link speed in Mbps
duplex: RockerPortDuplex
port link duplex
autoneg: RockerPortAutoneg
port link autoneg

Since

2.4

query-rocker-ports (Command)

Return rocker switch port information.

Arguments

name: string
Not documented

Returns

a list of RockerPort information

Since

2.4

Example

-> { "execute": "query-rocker-ports", "arguments": { "name": "sw1" } }
<- { "return": [ {"duplex": "full", "enabled": true, "name": "sw1.1",
                  "autoneg": "off", "link-up": true, "speed": 10000},
                 {"duplex": "full", "enabled": true, "name": "sw1.2",
                  "autoneg": "off", "link-up": true, "speed": 10000}
   ]}

RockerOfDpaFlowKey (Object)

Rocker switch OF-DPA flow key

Members

priority: int
key priority, 0 being lowest priority
tbl-id: int
flow table ID
in-pport: int (optional)
physical input port
tunnel-id: int (optional)
tunnel ID
vlan-id: int (optional)
VLAN ID
eth-type: int (optional)
Ethernet header type
eth-src: string (optional)
Ethernet header source MAC address
eth-dst: string (optional)
Ethernet header destination MAC address
ip-proto: int (optional)
IP Header protocol field
ip-tos: int (optional)
IP header TOS field
ip-dst: string (optional)
IP header destination address

Note

optional members may or may not appear in the flow key depending if they’re relevant to the flow key.

Since

2.4

RockerOfDpaFlowMask (Object)

Rocker switch OF-DPA flow mask

Members

in-pport: int (optional)
physical input port
tunnel-id: int (optional)
tunnel ID
vlan-id: int (optional)
VLAN ID
eth-src: string (optional)
Ethernet header source MAC address
eth-dst: string (optional)
Ethernet header destination MAC address
ip-proto: int (optional)
IP Header protocol field
ip-tos: int (optional)
IP header TOS field

Note

optional members may or may not appear in the flow mask depending if they’re relevant to the flow mask.

Since

2.4

RockerOfDpaFlowAction (Object)

Rocker switch OF-DPA flow action

Members

goto-tbl: int (optional)
next table ID
group-id: int (optional)
group ID
tunnel-lport: int (optional)
tunnel logical port ID
vlan-id: int (optional)
VLAN ID
new-vlan-id: int (optional)
new VLAN ID
out-pport: int (optional)
physical output port

Note

optional members may or may not appear in the flow action depending if they’re relevant to the flow action.

Since

2.4

RockerOfDpaFlow (Object)

Rocker switch OF-DPA flow

Members

cookie: int
flow unique cookie ID
hits: int
count of matches (hits) on flow
key: RockerOfDpaFlowKey
flow key
mask: RockerOfDpaFlowMask
flow mask
action: RockerOfDpaFlowAction
flow action

Since

2.4

query-rocker-of-dpa-flows (Command)

Return rocker OF-DPA flow information.

Arguments

name: string
switch name
tbl-id: int (optional)
flow table ID. If tbl-id is not specified, returns flow information for all tables.

Returns

rocker OF-DPA flow information

Since

2.4

Example

-> { "execute": "query-rocker-of-dpa-flows",
     "arguments": { "name": "sw1" } }
<- { "return": [ {"key": {"in-pport": 0, "priority": 1, "tbl-id": 0},
                  "hits": 138,
                  "cookie": 0,
                  "action": {"goto-tbl": 10},
                  "mask": {"in-pport": 4294901760}
                 },
                 {...more...},
   ]}

RockerOfDpaGroup (Object)

Rocker switch OF-DPA group

Members

id: int
group unique ID
type: int
group type
vlan-id: int (optional)
VLAN ID
pport: int (optional)
physical port number
index: int (optional)
group index, unique with group type
out-pport: int (optional)
output physical port number
group-id: int (optional)
next group ID
set-vlan-id: int (optional)
VLAN ID to set
pop-vlan: int (optional)
pop VLAN headr from packet
group-ids: array of int (optional)
list of next group IDs
set-eth-src: string (optional)
set source MAC address in Ethernet header
set-eth-dst: string (optional)
set destination MAC address in Ethernet header
ttl-check: int (optional)
perform TTL check

Note

optional members may or may not appear in the group depending if they’re relevant to the group type.

Since

2.4

query-rocker-of-dpa-groups (Command)

Return rocker OF-DPA group information.

Arguments

name: string
switch name
type: int (optional)
group type. If type is not specified, returns group information for all group types.

Returns

rocker OF-DPA group information

Since

2.4

Example

-> { "execute": "query-rocker-of-dpa-groups",
     "arguments": { "name": "sw1" } }
<- { "return": [ {"type": 0, "out-pport": 2,
                  "pport": 2, "vlan-id": 3841,
                  "pop-vlan": 1, "id": 251723778},
                 {"type": 0, "out-pport": 0,
                  "pport": 0, "vlan-id": 3841,
                  "pop-vlan": 1, "id": 251723776},
                 {"type": 0, "out-pport": 1,
                  "pport": 1, "vlan-id": 3840,
                  "pop-vlan": 1, "id": 251658241},
                 {"type": 0, "out-pport": 0,
                  "pport": 0, "vlan-id": 3840,
                  "pop-vlan": 1, "id": 251658240}
   ]}

TPM (trusted platform module) devices

TpmModel (Enum)

An enumeration of TPM models

Values

tpm-tis
TPM TIS model
tpm-crb
TPM CRB model (since 2.12)
tpm-spapr
TPM SPAPR model (since 5.0)

Since

1.5

query-tpm-models (Command)

Return a list of supported TPM models

Returns

a list of TpmModel

Since

1.5

Example

-> { "execute": "query-tpm-models" }
<- { "return": [ "tpm-tis", "tpm-crb", "tpm-spapr" ] }

TpmType (Enum)

An enumeration of TPM types

Values

passthrough
TPM passthrough type
emulator
Software Emulator TPM type Since: 2.11

Since

1.5

query-tpm-types (Command)

Return a list of supported TPM types

Returns

a list of TpmType

Since

1.5

Example

-> { "execute": "query-tpm-types" }
<- { "return": [ "passthrough", "emulator" ] }

TPMPassthroughOptions (Object)

Information about the TPM passthrough type

Members

path: string (optional)
string describing the path used for accessing the TPM device
cancel-path: string (optional)
string showing the TPM’s sysfs cancel file for cancellation of TPM commands while they are executing

Since

1.5

TPMEmulatorOptions (Object)

Information about the TPM emulator type

Members

chardev: string
Name of a unix socket chardev

Since

2.11

TpmTypeOptions (Object)

A union referencing different TPM backend types’ configuration options

Members

type
  • ‘passthrough’ The configuration options for the TPM passthrough type
  • ‘emulator’ The configuration options for TPM emulator backend type
data: TPMPassthroughOptions when type is "passthrough"
data: TPMEmulatorOptions when type is "emulator"

Since

1.5

TPMInfo (Object)

Information about the TPM

Members

id: string
The Id of the TPM
model: TpmModel
The TPM frontend model
options: TpmTypeOptions
The TPM (backend) type configuration options

Since

1.5

query-tpm (Command)

Return information about the TPM device

Returns

TPMInfo on success

Since

1.5

Example

-> { "execute": "query-tpm" }
<- { "return":
     [
       { "model": "tpm-tis",
         "options":
           { "type": "passthrough",
             "data":
               { "cancel-path": "/sys/class/misc/tpm0/device/cancel",
                 "path": "/dev/tpm0"
               }
           },
         "id": "tpm0"
       }
     ]
   }

Remote desktop

set_password (Command)

Sets the password of a remote display session.

Arguments

protocol: string
  • ‘vnc’ to modify the VNC server password
  • ‘spice’ to modify the Spice server password
password: string
the new password
connected: string (optional)
how to handle existing clients when changing the password. If nothing is specified, defaults to ‘keep’ ‘fail’ to fail the command if clients are connected ‘disconnect’ to disconnect existing clients ‘keep’ to maintain existing clients

Returns

  • Nothing on success
  • If Spice is not enabled, DeviceNotFound

Since

0.14.0

Example

-> { "execute": "set_password", "arguments": { "protocol": "vnc",
                                               "password": "secret" } }
<- { "return": {} }

expire_password (Command)

Expire the password of a remote display server.

Arguments

protocol: string
the name of the remote display protocol ‘vnc’ or ‘spice’
time: string

when to expire the password.

  • ‘now’ to expire the password immediately
  • ‘never’ to cancel password expiration
  • ‘+INT’ where INT is the number of seconds from now (integer)
  • ‘INT’ where INT is the absolute time in seconds

Returns

  • Nothing on success
  • If protocol is ‘spice’ and Spice is not active, DeviceNotFound

Since

0.14.0

Notes

Time is relative to the server and currently there is no way to coordinate server time with client time. It is not recommended to use the absolute time version of the time parameter unless you’re sure you are on the same machine as the QEMU instance.

Example

-> { "execute": "expire_password", "arguments": { "protocol": "vnc",
                                                  "time": "+60" } }
<- { "return": {} }

screendump (Command)

Write a PPM of the VGA screen to a file.

Arguments

filename: string
the path of a new PPM file to store the image
device: string (optional)
ID of the display device that should be dumped. If this parameter is missing, the primary display will be used. (Since 2.12)
head: int (optional)
head to use in case the device supports multiple heads. If this parameter is missing, head #0 will be used. Also note that the head can only be specified in conjunction with the device ID. (Since 2.12)

Returns

Nothing on success

Since

0.14.0

Example

-> { "execute": "screendump",
     "arguments": { "filename": "/tmp/image" } }
<- { "return": {} }

Spice

SpiceBasicInfo (Object)

The basic information for SPICE network connection

Members
host: string
IP address
port: string
port number
family: NetworkAddressFamily
address family
Since

2.1

If
defined(CONFIG_SPICE)

SpiceServerInfo (Object)

Information about a SPICE server

Members
auth: string (optional)
authentication method
The members of SpiceBasicInfo
Since

2.1

If
defined(CONFIG_SPICE)

SpiceChannel (Object)

Information about a SPICE client channel.

Members
connection-id: int
SPICE connection id number. All channels with the same id belong to the same SPICE session.
channel-type: int
SPICE channel type number. “1” is the main control channel, filter for this one if you want to track spice sessions only
channel-id: int
SPICE channel ID number. Usually “0”, might be different when multiple channels of the same type exist, such as multiple display channels in a multihead setup
tls: boolean
true if the channel is encrypted, false otherwise.
The members of SpiceBasicInfo
Since

0.14.0

If
defined(CONFIG_SPICE)

SpiceQueryMouseMode (Enum)

An enumeration of Spice mouse states.

Values
client
Mouse cursor position is determined by the client.
server
Mouse cursor position is determined by the server.
unknown
No information is available about mouse mode used by the spice server.
Note

spice/enums.h has a SpiceMouseMode already, hence the name.

Since

1.1

If
defined(CONFIG_SPICE)

SpiceInfo (Object)

Information about the SPICE session.

Members
enabled: boolean
true if the SPICE server is enabled, false otherwise
migrated: boolean
true if the last guest migration completed and spice migration had completed as well. false otherwise. (since 1.4)
host: string (optional)
The hostname the SPICE server is bound to. This depends on the name resolution on the host and may be an IP address.
port: int (optional)
The SPICE server’s port number.
compiled-version: string (optional)
SPICE server version.
tls-port: int (optional)
The SPICE server’s TLS port number.
auth: string (optional)

the current authentication type used by the server

  • ‘none’ if no authentication is being used
  • ‘spice’ uses SASL or direct TLS authentication, depending on command line options
mouse-mode: SpiceQueryMouseMode
The mode in which the mouse cursor is displayed currently. Can be determined by the client or the server, or unknown if spice server doesn’t provide this information. (since: 1.1)
channels: array of SpiceChannel (optional)
a list of SpiceChannel for each active spice channel
Since

0.14.0

If
defined(CONFIG_SPICE)

query-spice (Command)

Returns information about the current SPICE server

Returns

SpiceInfo

Since

0.14.0

Example
-> { "execute": "query-spice" }
<- { "return": {
         "enabled": true,
         "auth": "spice",
         "port": 5920,
         "tls-port": 5921,
         "host": "0.0.0.0",
         "channels": [
            {
               "port": "54924",
               "family": "ipv4",
               "channel-type": 1,
               "connection-id": 1804289383,
               "host": "127.0.0.1",
               "channel-id": 0,
               "tls": true
            },
            {
               "port": "36710",
               "family": "ipv4",
               "channel-type": 4,
               "connection-id": 1804289383,
               "host": "127.0.0.1",
               "channel-id": 0,
               "tls": false
            },
            [ ... more channels follow ... ]
         ]
      }
   }
If
defined(CONFIG_SPICE)

SPICE_CONNECTED (Event)

Emitted when a SPICE client establishes a connection

Arguments
server: SpiceBasicInfo
server information
client: SpiceBasicInfo
client information
Since

0.14.0

Example
<- { "timestamp": {"seconds": 1290688046, "microseconds": 388707},
     "event": "SPICE_CONNECTED",
     "data": {
       "server": { "port": "5920", "family": "ipv4", "host": "127.0.0.1"},
       "client": {"port": "52873", "family": "ipv4", "host": "127.0.0.1"}
   }}
If
defined(CONFIG_SPICE)

SPICE_INITIALIZED (Event)

Emitted after initial handshake and authentication takes place (if any) and the SPICE channel is up and running

Arguments
server: SpiceServerInfo
server information
client: SpiceChannel
client information
Since

0.14.0

Example
<- { "timestamp": {"seconds": 1290688046, "microseconds": 417172},
     "event": "SPICE_INITIALIZED",
     "data": {"server": {"auth": "spice", "port": "5921",
                         "family": "ipv4", "host": "127.0.0.1"},
              "client": {"port": "49004", "family": "ipv4", "channel-type": 3,
                         "connection-id": 1804289383, "host": "127.0.0.1",
                         "channel-id": 0, "tls": true}
   }}
If
defined(CONFIG_SPICE)

SPICE_DISCONNECTED (Event)

Emitted when the SPICE connection is closed

Arguments
server: SpiceBasicInfo
server information
client: SpiceBasicInfo
client information
Since

0.14.0

Example
<- { "timestamp": {"seconds": 1290688046, "microseconds": 388707},
     "event": "SPICE_DISCONNECTED",
     "data": {
       "server": { "port": "5920", "family": "ipv4", "host": "127.0.0.1"},
       "client": {"port": "52873", "family": "ipv4", "host": "127.0.0.1"}
   }}
If
defined(CONFIG_SPICE)

SPICE_MIGRATE_COMPLETED (Event)

Emitted when SPICE migration has completed

Since

1.3

Example
<- { "timestamp": {"seconds": 1290688046, "microseconds": 417172},
     "event": "SPICE_MIGRATE_COMPLETED" }
If
defined(CONFIG_SPICE)

VNC

VncBasicInfo (Object)

The basic information for vnc network connection

Members
host: string
IP address
service: string
The service name of the vnc port. This may depend on the host system’s service database so symbolic names should not be relied on.
family: NetworkAddressFamily
address family
websocket: boolean
true in case the socket is a websocket (since 2.3).
Since

2.1

If
defined(CONFIG_VNC)

VncServerInfo (Object)

The network connection information for server

Members
auth: string (optional)
authentication method used for the plain (non-websocket) VNC server
The members of VncBasicInfo
Since

2.1

If
defined(CONFIG_VNC)

VncClientInfo (Object)

Information about a connected VNC client.

Members
x509_dname: string (optional)
If x509 authentication is in use, the Distinguished Name of the client.
sasl_username: string (optional)
If SASL authentication is in use, the SASL username used for authentication.
The members of VncBasicInfo
Since

0.14.0

If
defined(CONFIG_VNC)

VncInfo (Object)

Information about the VNC session.

Members
enabled: boolean
true if the VNC server is enabled, false otherwise
host: string (optional)
The hostname the VNC server is bound to. This depends on the name resolution on the host and may be an IP address.
family: NetworkAddressFamily (optional)
  • ‘ipv6’ if the host is listening for IPv6 connections
  • ‘ipv4’ if the host is listening for IPv4 connections
  • ‘unix’ if the host is listening on a unix domain socket
  • ‘unknown’ otherwise
service: string (optional)
The service name of the server’s port. This may depends on the host system’s service database so symbolic names should not be relied on.
auth: string (optional)

the current authentication type used by the server

  • ‘none’ if no authentication is being used
  • ‘vnc’ if VNC authentication is being used
  • ‘vencrypt+plain’ if VEncrypt is used with plain text authentication
  • ‘vencrypt+tls+none’ if VEncrypt is used with TLS and no authentication
  • ‘vencrypt+tls+vnc’ if VEncrypt is used with TLS and VNC authentication
  • ‘vencrypt+tls+plain’ if VEncrypt is used with TLS and plain text auth
  • ‘vencrypt+x509+none’ if VEncrypt is used with x509 and no auth
  • ‘vencrypt+x509+vnc’ if VEncrypt is used with x509 and VNC auth
  • ‘vencrypt+x509+plain’ if VEncrypt is used with x509 and plain text auth
  • ‘vencrypt+tls+sasl’ if VEncrypt is used with TLS and SASL auth
  • ‘vencrypt+x509+sasl’ if VEncrypt is used with x509 and SASL auth
clients: array of VncClientInfo (optional)
a list of VncClientInfo of all currently connected clients
Since

0.14.0

If
defined(CONFIG_VNC)

VncPrimaryAuth (Enum)

vnc primary authentication method.

Values
none
Not documented
vnc
Not documented
ra2
Not documented
ra2ne
Not documented
tight
Not documented
ultra
Not documented
tls
Not documented
vencrypt
Not documented
sasl
Not documented
Since

2.3

If
defined(CONFIG_VNC)

VncVencryptSubAuth (Enum)

vnc sub authentication method with vencrypt.

Values
plain
Not documented
tls-none
Not documented
x509-none
Not documented
tls-vnc
Not documented
x509-vnc
Not documented
tls-plain
Not documented
x509-plain
Not documented
tls-sasl
Not documented
x509-sasl
Not documented
Since

2.3

If
defined(CONFIG_VNC)

VncServerInfo2 (Object)

The network connection information for server

Members
auth: VncPrimaryAuth
The current authentication type used by the servers
vencrypt: VncVencryptSubAuth (optional)
The vencrypt sub authentication type used by the servers, only specified in case auth == vencrypt.
The members of VncBasicInfo
Since

2.9

If
defined(CONFIG_VNC)

VncInfo2 (Object)

Information about a vnc server

Members
id: string
vnc server name.
server: array of VncServerInfo2
A list of VncBasincInfo describing all listening sockets. The list can be empty (in case the vnc server is disabled). It also may have multiple entries: normal + websocket, possibly also ipv4 + ipv6 in the future.
clients: array of VncClientInfo
A list of VncClientInfo of all currently connected clients. The list can be empty, for obvious reasons.
auth: VncPrimaryAuth
The current authentication type used by the non-websockets servers
vencrypt: VncVencryptSubAuth (optional)
The vencrypt authentication type used by the servers, only specified in case auth == vencrypt.
display: string (optional)
The display device the vnc server is linked to.
Since

2.3

If
defined(CONFIG_VNC)

query-vnc (Command)

Returns information about the current VNC server

Returns

VncInfo

Since

0.14.0

Example
-> { "execute": "query-vnc" }
<- { "return": {
         "enabled":true,
         "host":"0.0.0.0",
         "service":"50402",
         "auth":"vnc",
         "family":"ipv4",
         "clients":[
            {
               "host":"127.0.0.1",
               "service":"50401",
               "family":"ipv4"
            }
         ]
      }
   }
If
defined(CONFIG_VNC)

query-vnc-servers (Command)

Returns a list of vnc servers. The list can be empty.

Returns

a list of VncInfo2

Since

2.3

If
defined(CONFIG_VNC)

change-vnc-password (Command)

Change the VNC server password.

Arguments
password: string
the new password to use with VNC authentication
Since

1.1

Notes

An empty password in this command will set the password to the empty string. Existing clients are unaffected by executing this command.

If
defined(CONFIG_VNC)

VNC_CONNECTED (Event)

Emitted when a VNC client establishes a connection

Arguments
server: VncServerInfo
server information
client: VncBasicInfo
client information
Note

This event is emitted before any authentication takes place, thus the authentication ID is not provided

Since

0.13.0

Example
<- { "event": "VNC_CONNECTED",
     "data": {
           "server": { "auth": "sasl", "family": "ipv4",
                       "service": "5901", "host": "0.0.0.0" },
           "client": { "family": "ipv4", "service": "58425",
                       "host": "127.0.0.1" } },
     "timestamp": { "seconds": 1262976601, "microseconds": 975795 } }
If
defined(CONFIG_VNC)

VNC_INITIALIZED (Event)

Emitted after authentication takes place (if any) and the VNC session is made active

Arguments
server: VncServerInfo
server information
client: VncClientInfo
client information
Since

0.13.0

Example
<-  { "event": "VNC_INITIALIZED",
      "data": {
           "server": { "auth": "sasl", "family": "ipv4",
                       "service": "5901", "host": "0.0.0.0"},
           "client": { "family": "ipv4", "service": "46089",
                       "host": "127.0.0.1", "sasl_username": "luiz" } },
      "timestamp": { "seconds": 1263475302, "microseconds": 150772 } }
If
defined(CONFIG_VNC)

VNC_DISCONNECTED (Event)

Emitted when the connection is closed

Arguments
server: VncServerInfo
server information
client: VncClientInfo
client information
Since

0.13.0

Example
<- { "event": "VNC_DISCONNECTED",
     "data": {
           "server": { "auth": "sasl", "family": "ipv4",
                       "service": "5901", "host": "0.0.0.0" },
           "client": { "family": "ipv4", "service": "58425",
                       "host": "127.0.0.1", "sasl_username": "luiz" } },
     "timestamp": { "seconds": 1262976601, "microseconds": 975795 } }
If
defined(CONFIG_VNC)

Input

MouseInfo (Object)

Information about a mouse device.

Members

name: string
the name of the mouse device
index: int
the index of the mouse device
current: boolean
true if this device is currently receiving mouse events
absolute: boolean
true if this device supports absolute coordinates as input

Since

0.14.0

query-mice (Command)

Returns information about each active mouse device

Returns

a list of MouseInfo for each device

Since

0.14.0

Example

-> { "execute": "query-mice" }
<- { "return": [
         {
            "name":"QEMU Microsoft Mouse",
            "index":0,
            "current":false,
            "absolute":false
         },
         {
            "name":"QEMU PS/2 Mouse",
            "index":1,
            "current":true,
            "absolute":true
         }
      ]
   }

QKeyCode (Enum)

An enumeration of key name.

This is used by the send-key command.

Values

unmapped
since 2.0
pause
since 2.0
ro
since 2.4
kp_comma
since 2.4
kp_equals
since 2.6
power
since 2.6
hiragana
since 2.9
henkan
since 2.9
yen
since 2.9
sleep
since 2.10
wake
since 2.10
audionext
since 2.10
audioprev
since 2.10
audiostop
since 2.10
audioplay
since 2.10
audiomute
since 2.10
volumeup
since 2.10
volumedown
since 2.10
mediaselect
since 2.10
mail
since 2.10
calculator
since 2.10
computer
since 2.10
ac_home
since 2.10
ac_back
since 2.10
ac_forward
since 2.10
ac_refresh
since 2.10
ac_bookmarks
since 2.10
muhenkan
since 2.12
katakanahiragana
since 2.12
shift
Not documented
shift_r
Not documented
alt
Not documented
alt_r
Not documented
ctrl
Not documented
ctrl_r
Not documented
menu
Not documented
esc
Not documented
1
Not documented
2
Not documented
3
Not documented
4
Not documented
5
Not documented
6
Not documented
7
Not documented
8
Not documented
9
Not documented
0
Not documented
minus
Not documented
equal
Not documented
backspace
Not documented
tab
Not documented
q
Not documented
w
Not documented
e
Not documented
r
Not documented
t
Not documented
y
Not documented
u
Not documented
i
Not documented
o
Not documented
p
Not documented
bracket_left
Not documented
bracket_right
Not documented
ret
Not documented
a
Not documented
s
Not documented
d
Not documented
f
Not documented
g
Not documented
h
Not documented
j
Not documented
k
Not documented
l
Not documented
semicolon
Not documented
apostrophe
Not documented
grave_accent
Not documented
backslash
Not documented
z
Not documented
x
Not documented
c
Not documented
v
Not documented
b
Not documented
n
Not documented
m
Not documented
comma
Not documented
dot
Not documented
slash
Not documented
asterisk
Not documented
spc
Not documented
caps_lock
Not documented
f1
Not documented
f2
Not documented
f3
Not documented
f4
Not documented
f5
Not documented
f6
Not documented
f7
Not documented
f8
Not documented
f9
Not documented
f10
Not documented
num_lock
Not documented
scroll_lock
Not documented
kp_divide
Not documented
kp_multiply
Not documented
kp_subtract
Not documented
kp_add
Not documented
kp_enter
Not documented
kp_decimal
Not documented
sysrq
Not documented
kp_0
Not documented
kp_1
Not documented
kp_2
Not documented
kp_3
Not documented
kp_4
Not documented
kp_5
Not documented
kp_6
Not documented
kp_7
Not documented
kp_8
Not documented
kp_9
Not documented
less
Not documented
f11
Not documented
f12
Not documented
print
Not documented
home
Not documented
pgup
Not documented
pgdn
Not documented
end
Not documented
left
Not documented
up
Not documented
down
Not documented
right
Not documented
insert
Not documented
delete
Not documented
stop
Not documented
again
Not documented
props
Not documented
undo
Not documented
front
Not documented
copy
Not documented
open
Not documented
paste
Not documented
find
Not documented
cut
Not documented
lf
Not documented
help
Not documented
meta_l
Not documented
meta_r
Not documented
compose
Not documented
‘sysrq’ was mistakenly added to hack around the fact that the ps2 driver was not generating correct scancodes sequences when ‘alt+print’ was pressed. This flaw is now fixed and the ‘sysrq’ key serves no further purpose. Any further use of ‘sysrq’ will be transparently changed to ‘print’, so they are effectively synonyms.

Since

1.3.0

KeyValue (Object)

Represents a keyboard key.

Members

type
One of number, qcode
data: int when type is "number"
data: QKeyCode when type is "qcode"

Since

1.3.0

send-key (Command)

Send keys to guest.

Arguments

keys: array of KeyValue
An array of KeyValue elements. All KeyValues in this array are simultaneously sent to the guest. A KeyValue.number value is sent directly to the guest, while KeyValue.qcode must be a valid QKeyCode value
hold-time: int (optional)
time to delay key up events, milliseconds. Defaults to 100

Returns

  • Nothing on success
  • If key is unknown or redundant, InvalidParameter

Since

1.3.0

Example

-> { "execute": "send-key",
     "arguments": { "keys": [ { "type": "qcode", "data": "ctrl" },
                              { "type": "qcode", "data": "alt" },
                              { "type": "qcode", "data": "delete" } ] } }
<- { "return": {} }

InputButton (Enum)

Button of a pointer input device (mouse, tablet).

Values

side
front side button of a 5-button mouse (since 2.9)
extra
rear side button of a 5-button mouse (since 2.9)
left
Not documented
middle
Not documented
right
Not documented
wheel-up
Not documented
wheel-down
Not documented

Since

2.0

InputAxis (Enum)

Position axis of a pointer input device (mouse, tablet).

Values

x
Not documented
y
Not documented

Since

2.0

InputKeyEvent (Object)

Keyboard input event.

Members

key: KeyValue
Which key this event is for.
down: boolean
True for key-down and false for key-up events.

Since

2.0

InputBtnEvent (Object)

Pointer button input event.

Members

button: InputButton
Which button this event is for.
down: boolean
True for key-down and false for key-up events.

Since

2.0

InputMoveEvent (Object)

Pointer motion input event.

Members

axis: InputAxis
Which axis is referenced by value.
value: int
Pointer position. For absolute coordinates the valid range is 0 -> 0x7ffff

Since

2.0

InputEvent (Object)

Input event union.

Members

type

the input type, one of:

  • ‘key’: Input event of Keyboard
  • ‘btn’: Input event of pointer buttons
  • ‘rel’: Input event of relative pointer motion
  • ‘abs’: Input event of absolute pointer motion
data: InputKeyEvent when type is "key"
data: InputBtnEvent when type is "btn"
data: InputMoveEvent when type is "rel"
data: InputMoveEvent when type is "abs"

Since

2.0

input-send-event (Command)

Send input event(s) to guest.

The device and head parameters can be used to send the input event to specific input devices in case (a) multiple input devices of the same kind are added to the virtual machine and (b) you have configured input routing (see docs/multiseat.txt) for those input devices. The parameters work exactly like the device and head properties of input devices. If device is missing, only devices that have no input routing config are admissible. If device is specified, both input devices with and without input routing config are admissible, but devices with input routing config take precedence.

Arguments

device: string (optional)
display device to send event(s) to.
head: int (optional)
head to send event(s) to, in case the display device supports multiple scanouts.
events: array of InputEvent
List of InputEvent union.

Returns

Nothing on success.

Since

2.6

Note

The consoles are visible in the qom tree, under /backend/console[$index]. They have a device link and head property, so it is possible to map which console belongs to which device and display.

Example

1. Press left mouse button.

-> { "execute": "input-send-event",
    "arguments": { "device": "video0",
                   "events": [ { "type": "btn",
                   "data" : { "down": true, "button": "left" } } ] } }
<- { "return": {} }

-> { "execute": "input-send-event",
    "arguments": { "device": "video0",
                   "events": [ { "type": "btn",
                   "data" : { "down": false, "button": "left" } } ] } }
<- { "return": {} }

2. Press ctrl-alt-del.

-> { "execute": "input-send-event",
     "arguments": { "events": [
        { "type": "key", "data" : { "down": true,
          "key": {"type": "qcode", "data": "ctrl" } } },
        { "type": "key", "data" : { "down": true,
          "key": {"type": "qcode", "data": "alt" } } },
        { "type": "key", "data" : { "down": true,
          "key": {"type": "qcode", "data": "delete" } } } ] } }
<- { "return": {} }

3. Move mouse pointer to absolute coordinates (20000, 400).

-> { "execute": "input-send-event" ,
  "arguments": { "events": [
               { "type": "abs", "data" : { "axis": "x", "value" : 20000 } },
               { "type": "abs", "data" : { "axis": "y", "value" : 400 } } ] } }
<- { "return": {} }

GrabToggleKeys (Enum)

Keys to toggle input-linux between host and guest.

Values

ctrl-ctrl
Not documented
alt-alt
Not documented
shift-shift
Not documented
meta-meta
Not documented
scrolllock
Not documented
ctrl-scrolllock
Not documented

Since

4.0

DisplayGTK (Object)

GTK display options.

Members

grab-on-hover: boolean (optional)
Grab keyboard input on mouse hover.
zoom-to-fit: boolean (optional)
Zoom guest display to fit into the host window. When turned off the host window will be resized instead. In case the display device can notify the guest on window resizes (virtio-gpu) this will default to “on”, assuming the guest will resize the display to match the window size then. Otherwise it defaults to “off”. Since 3.1

Since

2.12

DisplayEGLHeadless (Object)

EGL headless display options.

Members

rendernode: string (optional)
Which DRM render node should be used. Default is the first available node on the host.

Since

3.1

DisplayGLMode (Enum)

Display OpenGL mode.

Values

off
Disable OpenGL (default).
on
Use OpenGL, pick context type automatically. Would better be named ‘auto’ but is called ‘on’ for backward compatibility with bool type.
core
Use OpenGL with Core (desktop) Context.
es
Use OpenGL with ES (embedded systems) Context.

Since

3.0

DisplayCurses (Object)

Curses display options.

Members

charset: string (optional)
Font charset used by guest (default: CP437).

Since

4.0

DisplayType (Enum)

Display (user interface) type.

Values

default
The default user interface, selecting from the first available of gtk, sdl, cocoa, and vnc.
none
No user interface or video output display. The guest will still see an emulated graphics card, but its output will not be displayed to the QEMU user.
gtk
The GTK user interface.
sdl
The SDL user interface.
egl-headless
No user interface, offload GL operations to a local DRI device. Graphical display need to be paired with VNC or Spice. (Since 3.1)
curses
Display video output via curses. For graphics device models which support a text mode, QEMU can display this output using a curses/ncurses interface. Nothing is displayed when the graphics device is in graphical mode or if the graphics device does not support a text mode. Generally only the VGA device models support text mode.
cocoa
The Cocoa user interface.
spice-app
Set up a Spice server and run the default associated application to connect to it. The server will redirect the serial console and QEMU monitors. (Since 4.0)

Since

2.12

DisplayOptions (Object)

Display (user interface) options.

Members

type: DisplayType
Which DisplayType qemu should use.
full-screen: boolean (optional)
Start user interface in fullscreen mode (default: off).
window-close: boolean (optional)
Allow to quit qemu with window close button (default: on).
show-cursor: boolean (optional)
Force showing the mouse cursor (default: off).
(since: 5.0)
gl: DisplayGLMode (optional)
Enable OpenGL support (default: off).
The members of DisplayGTK when type is "gtk"
The members of DisplayCurses when type is "curses"
The members of DisplayEGLHeadless when type is "egl-headless"

Since

2.12

query-display-options (Command)

Returns information about display configuration

Returns

DisplayOptions

Since

3.1

QAuthZListPolicy (Enum)

The authorization policy result

Values

deny
deny access
allow
allow access

Since

4.0

QAuthZListFormat (Enum)

The authorization policy match format

Values

exact
an exact string match
glob
string with ? and * shell wildcard support

Since

4.0

QAuthZListRule (Object)

A single authorization rule.

Members

match: string
a string or glob to match against a user identity
policy: QAuthZListPolicy
the result to return if match evaluates to true
format: QAuthZListFormat (optional)
the format of the match rule (default ‘exact’)

Since

4.0

QAuthZListRuleListHack (Object)

Not exposed via QMP; hack to generate QAuthZListRuleList for use internally by the code.

Members

unused: array of QAuthZListRule
Not documented

Since

4.0

Migration

MigrationStats (Object)

Detailed migration status.

Members

transferred: int
amount of bytes already transferred to the target VM
remaining: int
amount of bytes remaining to be transferred to the target VM
total: int
total amount of bytes involved in the migration process
duplicate: int
number of duplicate (zero) pages (since 1.2)
skipped: int
number of skipped zero pages (since 1.5)
normal: int
number of normal pages (since 1.2)
normal-bytes: int
number of normal bytes sent (since 1.2)
dirty-pages-rate: int
number of pages dirtied by second by the guest (since 1.3)
mbps: number
throughput in megabits/sec. (since 1.6)
dirty-sync-count: int
number of times that dirty ram was synchronized (since 2.1)
postcopy-requests: int
The number of page requests received from the destination (since 2.7)
page-size: int
The number of bytes per page for the various page-based statistics (since 2.10)
multifd-bytes: int
The number of bytes sent through multifd (since 3.0)
pages-per-second: int
the number of memory pages transferred per second (Since 4.0)

Since

0.14.0

XBZRLECacheStats (Object)

Detailed XBZRLE migration cache statistics

Members

cache-size: int
XBZRLE cache size
bytes: int
amount of bytes already transferred to the target VM
pages: int
amount of pages transferred to the target VM
cache-miss: int
number of cache miss
cache-miss-rate: number
rate of cache miss (since 2.1)
overflow: int
number of overflows

Since

1.2

CompressionStats (Object)

Detailed migration compression statistics

Members

pages: int
amount of pages compressed and transferred to the target VM
busy: int
count of times that no free thread was available to compress data
busy-rate: number
rate of thread busy
compressed-size: int
amount of bytes after compression
compression-rate: number
rate of compressed size

Since

3.1

MigrationStatus (Enum)

An enumeration of migration status.

Values

none
no migration has ever happened.
setup
migration process has been initiated.
cancelling
in the process of cancelling migration.
cancelled
cancelling migration is finished.
active
in the process of doing migration.
postcopy-active
like active, but now in postcopy mode. (since 2.5)
postcopy-paused
during postcopy but paused. (since 3.0)
postcopy-recover
trying to recover from a paused postcopy. (since 3.0)
completed
migration is finished.
failed
some error occurred during migration process.
colo
VM is in the process of fault tolerance, VM can not get into this state unless colo capability is enabled for migration. (since 2.8)
pre-switchover
Paused before device serialisation. (since 2.11)
device
During device serialisation when pause-before-switchover is enabled (since 2.11)
wait-unplug
wait for device unplug request by guest OS to be completed. (since 4.2)

Since

2.3

MigrationInfo (Object)

Information about current migration process.

Members

status: MigrationStatus (optional)
MigrationStatus describing the current migration status. If this field is not returned, no migration process has been initiated
ram: MigrationStats (optional)
MigrationStats containing detailed migration status, only returned if status is ‘active’ or ‘completed’(since 1.2)
disk: MigrationStats (optional)
MigrationStats containing detailed disk migration status, only returned if status is ‘active’ and it is a block migration
xbzrle-cache: XBZRLECacheStats (optional)
XBZRLECacheStats containing detailed XBZRLE migration statistics, only returned if XBZRLE feature is on and status is ‘active’ or ‘completed’ (since 1.2)
total-time: int (optional)
total amount of milliseconds since migration started. If migration has ended, it returns the total migration time. (since 1.2)
downtime: int (optional)
only present when migration finishes correctly total downtime in milliseconds for the guest. (since 1.3)
expected-downtime: int (optional)
only present while migration is active expected downtime in milliseconds for the guest in last walk of the dirty bitmap. (since 1.3)
setup-time: int (optional)
amount of setup time in milliseconds before the iterations begin but after the QMP command is issued. This is designed to provide an accounting of any activities (such as RDMA pinning) which may be expensive, but do not actually occur during the iterative migration rounds themselves. (since 1.6)
cpu-throttle-percentage: int (optional)
percentage of time guest cpus are being throttled during auto-converge. This is only present when auto-converge has started throttling guest cpus. (Since 2.7)
error-desc: string (optional)
the human readable error description string, when status is ‘failed’. Clients should not attempt to parse the error strings. (Since 2.7)
postcopy-blocktime: int (optional)
total time when all vCPU were blocked during postcopy live migration. This is only present when the postcopy-blocktime migration capability is enabled. (Since 3.0)
postcopy-vcpu-blocktime: array of int (optional)
list of the postcopy blocktime per vCPU. This is only present when the postcopy-blocktime migration capability is enabled. (Since 3.0)
compression: CompressionStats (optional)
migration compression statistics, only returned if compression feature is on and status is ‘active’ or ‘completed’ (Since 3.1)
socket-address: array of SocketAddress (optional)
Only used for tcp, to know what the real port is (Since 4.0)

Since

0.14.0

query-migrate (Command)

Returns information about current migration process. If migration is active there will be another json-object with RAM migration status and if block migration is active another one with block migration status.

Returns

MigrationInfo

Since

0.14.0

Example

1. Before the first migration

-> { "execute": "query-migrate" }
<- { "return": {} }

2. Migration is done and has succeeded

-> { "execute": "query-migrate" }
<- { "return": {
        "status": "completed",
        "total-time":12345,
        "setup-time":12345,
        "downtime":12345,
        "ram":{
          "transferred":123,
          "remaining":123,
          "total":246,
          "duplicate":123,
          "normal":123,
          "normal-bytes":123456,
          "dirty-sync-count":15
        }
     }
   }

3. Migration is done and has failed

-> { "execute": "query-migrate" }
<- { "return": { "status": "failed" } }

4. Migration is being performed and is not a block migration:

-> { "execute": "query-migrate" }
<- {
      "return":{
         "status":"active",
         "total-time":12345,
         "setup-time":12345,
         "expected-downtime":12345,
         "ram":{
            "transferred":123,
            "remaining":123,
            "total":246,
            "duplicate":123,
            "normal":123,
            "normal-bytes":123456,
            "dirty-sync-count":15
         }
      }
   }

5. Migration is being performed and is a block migration:

-> { "execute": "query-migrate" }
<- {
      "return":{
         "status":"active",
         "total-time":12345,
         "setup-time":12345,
         "expected-downtime":12345,
         "ram":{
            "total":1057024,
            "remaining":1053304,
            "transferred":3720,
            "duplicate":123,
            "normal":123,
            "normal-bytes":123456,
            "dirty-sync-count":15
         },
         "disk":{
            "total":20971520,
            "remaining":20880384,
            "transferred":91136
         }
      }
   }

6. Migration is being performed and XBZRLE is active:

-> { "execute": "query-migrate" }
<- {
      "return":{
         "status":"active",
         "total-time":12345,
         "setup-time":12345,
         "expected-downtime":12345,
         "ram":{
            "total":1057024,
            "remaining":1053304,
            "transferred":3720,
            "duplicate":10,
            "normal":3333,
            "normal-bytes":3412992,
            "dirty-sync-count":15
         },
         "xbzrle-cache":{
            "cache-size":67108864,
            "bytes":20971520,
            "pages":2444343,
            "cache-miss":2244,
            "cache-miss-rate":0.123,
            "overflow":34434
         }
      }
   }

MigrationCapability (Enum)

Migration capabilities enumeration

Values

xbzrle
Migration supports xbzrle (Xor Based Zero Run Length Encoding). This feature allows us to minimize migration traffic for certain work loads, by sending compressed difference of the pages
rdma-pin-all
Controls whether or not the entire VM memory footprint is mlock()’d on demand or all at once. Refer to docs/rdma.txt for usage. Disabled by default. (since 2.0)
zero-blocks
During storage migration encode blocks of zeroes efficiently. This essentially saves 1MB of zeroes per block on the wire. Enabling requires source and target VM to support this feature. To enable it is sufficient to enable the capability on the source VM. The feature is disabled by default. (since 1.6)
compress
Use multiple compression threads to accelerate live migration. This feature can help to reduce the migration traffic, by sending compressed pages. Please note that if compress and xbzrle are both on, compress only takes effect in the ram bulk stage, after that, it will be disabled and only xbzrle takes effect, this can help to minimize migration traffic. The feature is disabled by default. (since 2.4 )
events
generate events for each migration state change (since 2.4 )
auto-converge
If enabled, QEMU will automatically throttle down the guest to speed up convergence of RAM migration. (since 1.6)
postcopy-ram
Start executing on the migration target before all of RAM has been migrated, pulling the remaining pages along as needed. The capacity must have the same setting on both source and target or migration will not even start. NOTE: If the migration fails during postcopy the VM will fail. (since 2.6)
x-colo
If enabled, migration will never end, and the state of the VM on the primary side will be migrated continuously to the VM on secondary side, this process is called COarse-Grain LOck Stepping (COLO) for Non-stop Service. (since 2.8)
release-ram
if enabled, qemu will free the migrated ram pages on the source during postcopy-ram migration. (since 2.9)
block
If enabled, QEMU will also migrate the contents of all block devices. Default is disabled. A possible alternative uses mirror jobs to a builtin NBD server on the destination, which offers more flexibility. (Since 2.10)
return-path
If enabled, migration will use the return path even for precopy. (since 2.10)
pause-before-switchover
Pause outgoing migration before serialising device state and before disabling block IO (since 2.11)
multifd
Use more than one fd for migration (since 4.0)
dirty-bitmaps
If enabled, QEMU will migrate named dirty bitmaps. (since 2.12)
postcopy-blocktime
Calculate downtime for postcopy live migration (since 3.0)
late-block-activate
If enabled, the destination will not activate block devices (and thus take locks) immediately at the end of migration. (since 3.0)
x-ignore-shared
If enabled, QEMU will not migrate shared memory (since 4.0)
validate-uuid
Send the UUID of the source to allow the destination to ensure it is the same. (since 4.2)

Since

1.2

MigrationCapabilityStatus (Object)

Migration capability information

Members

capability: MigrationCapability
capability enum
state: boolean
capability state bool

Since

1.2

migrate-set-capabilities (Command)

Enable/Disable the following migration capabilities (like xbzrle)

Arguments

capabilities: array of MigrationCapabilityStatus
json array of capability modifications to make

Since

1.2

Example

-> { "execute": "migrate-set-capabilities" , "arguments":
     { "capabilities": [ { "capability": "xbzrle", "state": true } ] } }

query-migrate-capabilities (Command)

Returns information about the current migration capabilities status

Returns

MigrationCapabilitiesStatus

Since

1.2

Example

-> { "execute": "query-migrate-capabilities" }
<- { "return": [
      {"state": false, "capability": "xbzrle"},
      {"state": false, "capability": "rdma-pin-all"},
      {"state": false, "capability": "auto-converge"},
      {"state": false, "capability": "zero-blocks"},
      {"state": false, "capability": "compress"},
      {"state": true, "capability": "events"},
      {"state": false, "capability": "postcopy-ram"},
      {"state": false, "capability": "x-colo"}
   ]}

MultiFDCompression (Enum)

An enumeration of multifd compression methods.

Values

none
no compression.
zlib
use zlib compression method.
zstd (If: defined(CONFIG_ZSTD))
use zstd compression method.

Since

5.0

MigrationParameter (Enum)

Migration parameters enumeration

Values

announce-initial
Initial delay (in milliseconds) before sending the first announce (Since 4.0)
announce-max
Maximum delay (in milliseconds) between packets in the announcement (Since 4.0)
announce-rounds
Number of self-announce packets sent after migration (Since 4.0)
announce-step
Increase in delay (in milliseconds) between subsequent packets in the announcement (Since 4.0)
compress-level
Set the compression level to be used in live migration, the compression level is an integer between 0 and 9, where 0 means no compression, 1 means the best compression speed, and 9 means best compression ratio which will consume more CPU.
compress-threads
Set compression thread count to be used in live migration, the compression thread count is an integer between 1 and 255.
compress-wait-thread
Controls behavior when all compression threads are currently busy. If true (default), wait for a free compression thread to become available; otherwise, send the page uncompressed. (Since 3.1)
decompress-threads
Set decompression thread count to be used in live migration, the decompression thread count is an integer between 1 and 255. Usually, decompression is at least 4 times as fast as compression, so set the decompress-threads to the number about 1/4 of compress-threads is adequate.
cpu-throttle-initial
Initial percentage of time guest cpus are throttled when migration auto-converge is activated. The default value is 20. (Since 2.7)
cpu-throttle-increment
throttle percentage increase each time auto-converge detects that migration is not making progress. The default value is 10. (Since 2.7)
tls-creds
ID of the ‘tls-creds’ object that provides credentials for establishing a TLS connection over the migration data channel. On the outgoing side of the migration, the credentials must be for a ‘client’ endpoint, while for the incoming side the credentials must be for a ‘server’ endpoint. Setting this will enable TLS for all migrations. The default is unset, resulting in unsecured migration at the QEMU level. (Since 2.7)
tls-hostname
hostname of the target host for the migration. This is required when using x509 based TLS credentials and the migration URI does not already include a hostname. For example if using fd: or exec: based migration, the hostname must be provided so that the server’s x509 certificate identity can be validated. (Since 2.7)
tls-authz
ID of the ‘authz’ object subclass that provides access control checking of the TLS x509 certificate distinguished name. This object is only resolved at time of use, so can be deleted and recreated on the fly while the migration server is active. If missing, it will default to denying access (Since 4.0)
max-bandwidth
to set maximum speed for migration. maximum speed in bytes per second. (Since 2.8)
downtime-limit
set maximum tolerated downtime for migration. maximum downtime in milliseconds (Since 2.8)
x-checkpoint-delay
The delay time (in ms) between two COLO checkpoints in periodic mode. (Since 2.8)
block-incremental
Affects how much storage is migrated when the block migration capability is enabled. When false, the entire storage backing chain is migrated into a flattened image at the destination; when true, only the active qcow2 layer is migrated and the destination must already have access to the same backing chain as was used on the source. (since 2.10)
multifd-channels
Number of channels used to migrate data in parallel. This is the same number that the number of sockets used for migration. The default value is 2 (since 4.0)
xbzrle-cache-size
cache size to be used by XBZRLE migration. It needs to be a multiple of the target page size and a power of 2 (Since 2.11)
max-postcopy-bandwidth
Background transfer bandwidth during postcopy. Defaults to 0 (unlimited). In bytes per second. (Since 3.0)
max-cpu-throttle
maximum cpu throttle percentage. Defaults to 99. (Since 3.1)
multifd-compression
Which compression method to use. Defaults to none. (Since 5.0)
multifd-zlib-level
Set the compression level to be used in live migration, the compression level is an integer between 0 and 9, where 0 means no compression, 1 means the best compression speed, and 9 means best compression ratio which will consume more CPU. Defaults to 1. (Since 5.0)
multifd-zstd-level
Set the compression level to be used in live migration, the compression level is an integer between 0 and 20, where 0 means no compression, 1 means the best compression speed, and 20 means best compression ratio which will consume more CPU. Defaults to 1. (Since 5.0)

Since

2.4

MigrateSetParameters (Object)

Members

announce-initial: int (optional)
Initial delay (in milliseconds) before sending the first announce (Since 4.0)
announce-max: int (optional)
Maximum delay (in milliseconds) between packets in the announcement (Since 4.0)
announce-rounds: int (optional)
Number of self-announce packets sent after migration (Since 4.0)
announce-step: int (optional)
Increase in delay (in milliseconds) between subsequent packets in the announcement (Since 4.0)
compress-level: int (optional)
compression level
compress-threads: int (optional)
compression thread count
compress-wait-thread: boolean (optional)
Controls behavior when all compression threads are currently busy. If true (default), wait for a free compression thread to become available; otherwise, send the page uncompressed. (Since 3.1)
decompress-threads: int (optional)
decompression thread count
cpu-throttle-initial: int (optional)
Initial percentage of time guest cpus are throttled when migration auto-converge is activated. The default value is 20. (Since 2.7)
cpu-throttle-increment: int (optional)
throttle percentage increase each time auto-converge detects that migration is not making progress. The default value is 10. (Since 2.7)
tls-creds: StrOrNull (optional)
ID of the ‘tls-creds’ object that provides credentials for establishing a TLS connection over the migration data channel. On the outgoing side of the migration, the credentials must be for a ‘client’ endpoint, while for the incoming side the credentials must be for a ‘server’ endpoint. Setting this to a non-empty string enables TLS for all migrations. An empty string means that QEMU will use plain text mode for migration, rather than TLS (Since 2.9) Previously (since 2.7), this was reported by omitting tls-creds instead.
tls-hostname: StrOrNull (optional)
hostname of the target host for the migration. This is required when using x509 based TLS credentials and the migration URI does not already include a hostname. For example if using fd: or exec: based migration, the hostname must be provided so that the server’s x509 certificate identity can be validated. (Since 2.7) An empty string means that QEMU will use the hostname associated with the migration URI, if any. (Since 2.9) Previously (since 2.7), this was reported by omitting tls-hostname instead.
max-bandwidth: int (optional)
to set maximum speed for migration. maximum speed in bytes per second. (Since 2.8)
downtime-limit: int (optional)
set maximum tolerated downtime for migration. maximum downtime in milliseconds (Since 2.8)
x-checkpoint-delay: int (optional)
the delay time between two COLO checkpoints. (Since 2.8)
block-incremental: boolean (optional)
Affects how much storage is migrated when the block migration capability is enabled. When false, the entire storage backing chain is migrated into a flattened image at the destination; when true, only the active qcow2 layer is migrated and the destination must already have access to the same backing chain as was used on the source. (since 2.10)
multifd-channels: int (optional)
Number of channels used to migrate data in parallel. This is the same number that the number of sockets used for migration. The default value is 2 (since 4.0)
xbzrle-cache-size: int (optional)
cache size to be used by XBZRLE migration. It needs to be a multiple of the target page size and a power of 2 (Since 2.11)
max-postcopy-bandwidth: int (optional)
Background transfer bandwidth during postcopy. Defaults to 0 (unlimited). In bytes per second. (Since 3.0)
max-cpu-throttle: int (optional)
maximum cpu throttle percentage. The default value is 99. (Since 3.1)
multifd-compression: MultiFDCompression (optional)
Which compression method to use. Defaults to none. (Since 5.0)
multifd-zlib-level: int (optional)
Set the compression level to be used in live migration, the compression level is an integer between 0 and 9, where 0 means no compression, 1 means the best compression speed, and 9 means best compression ratio which will consume more CPU. Defaults to 1. (Since 5.0)
multifd-zstd-level: int (optional)
Set the compression level to be used in live migration, the compression level is an integer between 0 and 20, where 0 means no compression, 1 means the best compression speed, and 20 means best compression ratio which will consume more CPU. Defaults to 1. (Since 5.0)
tls-authz: StrOrNull (optional)
Not documented

Since

2.4

migrate-set-parameters (Command)

Set various migration parameters.

Arguments

The members of MigrateSetParameters

Since

2.4

Example

-> { "execute": "migrate-set-parameters" ,
     "arguments": { "compress-level": 1 } }

MigrationParameters (Object)

The optional members aren’t actually optional.

Members

announce-initial: int (optional)
Initial delay (in milliseconds) before sending the first announce (Since 4.0)
announce-max: int (optional)
Maximum delay (in milliseconds) between packets in the announcement (Since 4.0)
announce-rounds: int (optional)
Number of self-announce packets sent after migration (Since 4.0)
announce-step: int (optional)
Increase in delay (in milliseconds) between subsequent packets in the announcement (Since 4.0)
compress-level: int (optional)
compression level
compress-threads: int (optional)
compression thread count
compress-wait-thread: boolean (optional)
Controls behavior when all compression threads are currently busy. If true (default), wait for a free compression thread to become available; otherwise, send the page uncompressed. (Since 3.1)
decompress-threads: int (optional)
decompression thread count
cpu-throttle-initial: int (optional)
Initial percentage of time guest cpus are throttled when migration auto-converge is activated. (Since 2.7)
cpu-throttle-increment: int (optional)
throttle percentage increase each time auto-converge detects that migration is not making progress. (Since 2.7)
tls-creds: string (optional)
ID of the ‘tls-creds’ object that provides credentials for establishing a TLS connection over the migration data channel. On the outgoing side of the migration, the credentials must be for a ‘client’ endpoint, while for the incoming side the credentials must be for a ‘server’ endpoint. An empty string means that QEMU will use plain text mode for migration, rather than TLS (Since 2.7) Note: 2.8 reports this by omitting tls-creds instead.
tls-hostname: string (optional)
hostname of the target host for the migration. This is required when using x509 based TLS credentials and the migration URI does not already include a hostname. For example if using fd: or exec: based migration, the hostname must be provided so that the server’s x509 certificate identity can be validated. (Since 2.7) An empty string means that QEMU will use the hostname associated with the migration URI, if any. (Since 2.9) Note: 2.8 reports this by omitting tls-hostname instead.
tls-authz: string (optional)
ID of the ‘authz’ object subclass that provides access control checking of the TLS x509 certificate distinguished name. (Since 4.0)
max-bandwidth: int (optional)
to set maximum speed for migration. maximum speed in bytes per second. (Since 2.8)
downtime-limit: int (optional)
set maximum tolerated downtime for migration. maximum downtime in milliseconds (Since 2.8)
x-checkpoint-delay: int (optional)
the delay time between two COLO checkpoints. (Since 2.8)
block-incremental: boolean (optional)
Affects how much storage is migrated when the block migration capability is enabled. When false, the entire storage backing chain is migrated into a flattened image at the destination; when true, only the active qcow2 layer is migrated and the destination must already have access to the same backing chain as was used on the source. (since 2.10)
multifd-channels: int (optional)
Number of channels used to migrate data in parallel. This is the same number that the number of sockets used for migration. The default value is 2 (since 4.0)
xbzrle-cache-size: int (optional)
cache size to be used by XBZRLE migration. It needs to be a multiple of the target page size and a power of 2 (Since 2.11)
max-postcopy-bandwidth: int (optional)
Background transfer bandwidth during postcopy. Defaults to 0 (unlimited). In bytes per second. (Since 3.0)
max-cpu-throttle: int (optional)
maximum cpu throttle percentage. Defaults to 99. (Since 3.1)
multifd-compression: MultiFDCompression (optional)
Which compression method to use. Defaults to none. (Since 5.0)
multifd-zlib-level: int (optional)
Set the compression level to be used in live migration, the compression level is an integer between 0 and 9, where 0 means no compression, 1 means the best compression speed, and 9 means best compression ratio which will consume more CPU. Defaults to 1. (Since 5.0)
multifd-zstd-level: int (optional)
Set the compression level to be used in live migration, the compression level is an integer between 0 and 20, where 0 means no compression, 1 means the best compression speed, and 20 means best compression ratio which will consume more CPU. Defaults to 1. (Since 5.0)

Since

2.4

query-migrate-parameters (Command)

Returns information about the current migration parameters

Returns

MigrationParameters

Since

2.4

Example

-> { "execute": "query-migrate-parameters" }
<- { "return": {
         "decompress-threads": 2,
         "cpu-throttle-increment": 10,
         "compress-threads": 8,
         "compress-level": 1,
         "cpu-throttle-initial": 20,
         "max-bandwidth": 33554432,
         "downtime-limit": 300
      }
   }

client_migrate_info (Command)

Set migration information for remote display. This makes the server ask the client to automatically reconnect using the new parameters once migration finished successfully. Only implemented for SPICE.

Arguments

protocol: string
must be “spice”
hostname: string
migration target hostname
port: int (optional)
spice tcp port for plaintext channels
tls-port: int (optional)
spice tcp port for tls-secured channels
cert-subject: string (optional)
server certificate subject

Since

0.14.0

Example

-> { "execute": "client_migrate_info",
     "arguments": { "protocol": "spice",
                    "hostname": "virt42.lab.kraxel.org",
                    "port": 1234 } }
<- { "return": {} }

migrate-start-postcopy (Command)

Followup to a migration command to switch the migration to postcopy mode. The postcopy-ram capability must be set on both source and destination before the original migration command.

Since

2.5

Example

-> { "execute": "migrate-start-postcopy" }
<- { "return": {} }

MIGRATION (Event)

Emitted when a migration event happens

Arguments

status: MigrationStatus
MigrationStatus describing the current migration status.

Since

2.4

Example

<- {"timestamp": {"seconds": 1432121972, "microseconds": 744001},
    "event": "MIGRATION",
    "data": {"status": "completed"} }

MIGRATION_PASS (Event)

Emitted from the source side of a migration at the start of each pass (when it syncs the dirty bitmap)

Arguments

pass: int
An incrementing count (starting at 1 on the first pass)

Since

2.6

Example

{ "timestamp": {"seconds": 1449669631, "microseconds": 239225},
  "event": "MIGRATION_PASS", "data": {"pass": 2} }

COLOMessage (Enum)

The message transmission between Primary side and Secondary side.

Values

checkpoint-ready
Secondary VM (SVM) is ready for checkpointing
checkpoint-request
Primary VM (PVM) tells SVM to prepare for checkpointing
checkpoint-reply
SVM gets PVM’s checkpoint request
vmstate-send
VM’s state will be sent by PVM.
vmstate-size
The total size of VMstate.
vmstate-received
VM’s state has been received by SVM.
vmstate-loaded
VM’s state has been loaded by SVM.

Since

2.8

COLOMode (Enum)

The COLO current mode.

Values

none
COLO is disabled.
primary
COLO node in primary side.
secondary
COLO node in slave side.

Since

2.8

FailoverStatus (Enum)

An enumeration of COLO failover status

Values

none
no failover has ever happened
require
got failover requirement but not handled
active
in the process of doing failover
completed
finish the process of failover
relaunch
restart the failover process, from ‘none’ -> ‘completed’ (Since 2.9)

Since

2.8

COLO_EXIT (Event)

Emitted when VM finishes COLO mode due to some errors happening or at the request of users.

Arguments

mode: COLOMode
report COLO mode when COLO exited.
reason: COLOExitReason
describes the reason for the COLO exit.

Since

3.1

Example

<- { "timestamp": {"seconds": 2032141960, "microseconds": 417172},
     "event": "COLO_EXIT", "data": {"mode": "primary", "reason": "request" } }

COLOExitReason (Enum)

The reason for a COLO exit.

Values

none
failover has never happened. This state does not occur in the COLO_EXIT event, and is only visible in the result of query-colo-status.
request
COLO exit is due to an external request.
error
COLO exit is due to an internal error.
processing
COLO is currently handling a failover (since 4.0).

Since

3.1

x-colo-lost-heartbeat (Command)

Tell qemu that heartbeat is lost, request it to do takeover procedures. If this command is sent to the PVM, the Primary side will exit COLO mode. If sent to the Secondary, the Secondary side will run failover work, then takes over server operation to become the service VM.

Since

2.8

Example

-> { "execute": "x-colo-lost-heartbeat" }
<- { "return": {} }

migrate_cancel (Command)

Cancel the current executing migration process.

Returns

nothing on success

Notes

This command succeeds even if there is no migration process running.

Since

0.14.0

Example

-> { "execute": "migrate_cancel" }
<- { "return": {} }

migrate-continue (Command)

Continue migration when it’s in a paused state.

Arguments

state: MigrationStatus
The state the migration is currently expected to be in

Returns

nothing on success

Since

2.11

Example

-> { "execute": "migrate-continue" , "arguments":
     { "state": "pre-switchover" } }
<- { "return": {} }

migrate_set_downtime (Command)

Set maximum tolerated downtime for migration.

Arguments

value: number
maximum downtime in seconds

Returns

nothing on success

Notes

This command is deprecated in favor of ‘migrate-set-parameters’

Since

0.14.0

Example

-> { "execute": "migrate_set_downtime", "arguments": { "value": 0.1 } }
<- { "return": {} }

migrate_set_speed (Command)

Set maximum speed for migration.

Arguments

value: int
maximum speed in bytes per second.

Returns

nothing on success

Notes

This command is deprecated in favor of ‘migrate-set-parameters’

Since

0.14.0

Example

-> { "execute": "migrate_set_speed", "arguments": { "value": 1024 } }
<- { "return": {} }

migrate-set-cache-size (Command)

Set cache size to be used by XBZRLE migration

Arguments

value: int
cache size in bytes
The size will be rounded down to the nearest power of 2. The cache size can be modified before and during ongoing migration

Returns

nothing on success

Notes

This command is deprecated in favor of ‘migrate-set-parameters’

Since

1.2

Example

-> { "execute": "migrate-set-cache-size",
     "arguments": { "value": 536870912 } }
<- { "return": {} }

query-migrate-cache-size (Command)

Query migration XBZRLE cache size

Returns

XBZRLE cache size in bytes

Notes

This command is deprecated in favor of ‘query-migrate-parameters’

Since

1.2

Example

-> { "execute": "query-migrate-cache-size" }
<- { "return": 67108864 }

migrate (Command)

Migrates the current running guest to another Virtual Machine.

Arguments

uri: string
the Uniform Resource Identifier of the destination VM
blk: boolean (optional)
do block migration (full disk copy)
inc: boolean (optional)
incremental disk copy migration
detach: boolean (optional)
this argument exists only for compatibility reasons and is ignored by QEMU
resume: boolean (optional)
resume one paused migration, default “off”. (since 3.0)

Returns

nothing on success

Since

0.14.0

Notes

  1. The ‘query-migrate’ command should be used to check migration’s progress and final result (this information is provided by the ‘status’ member)
  2. All boolean arguments default to false
  3. The user Monitor’s “detach” argument is invalid in QMP and should not be used

Example

-> { "execute": "migrate", "arguments": { "uri": "tcp:0:4446" } }
<- { "return": {} }

migrate-incoming (Command)

Start an incoming migration, the qemu must have been started with -incoming defer

Arguments

uri: string
The Uniform Resource Identifier identifying the source or address to listen on

Returns

nothing on success

Since