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authorLuiz Capitulino <lcapitulino@redhat.com>2013-09-10 17:00:45 -0400
committerLuiz Capitulino <lcapitulino@redhat.com>2013-09-18 08:57:02 -0400
commit7537fe0487c3f7991584ca1c4bf9b6c58cd33968 (patch)
tree118664e8db755f95683b4e141724e802a2c818b0 /QMP
parentd076a2adddece29ad33afcce01e441bfc1c6923d (diff)
QMP: QMP/ -> docs/qmp/
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
Diffstat (limited to 'QMP')
-rw-r--r--QMP/README88
-rw-r--r--QMP/qmp-events.txt502
-rw-r--r--QMP/qmp-spec.txt282
3 files changed, 0 insertions, 872 deletions
diff --git a/QMP/README b/QMP/README
deleted file mode 100644
index c95a08c234..0000000000
--- a/QMP/README
+++ /dev/null
@@ -1,88 +0,0 @@
- QEMU Monitor Protocol
- =====================
-
-Introduction
--------------
-
-The QEMU Monitor Protocol (QMP) allows applications to communicate with
-QEMU's Monitor.
-
-QMP is JSON[1] based and currently has the following features:
-
-- Lightweight, text-based, easy to parse data format
-- Asynchronous messages support (ie. events)
-- Capabilities Negotiation
-
-For detailed information on QMP's usage, please, refer to the following files:
-
-o qmp-spec.txt QEMU Monitor Protocol current specification
-o qmp-commands.txt QMP supported commands (auto-generated at build-time)
-o qmp-events.txt List of available asynchronous events
-
-There is also a simple Python script called 'qmp-shell' available.
-
-IMPORTANT: It's strongly recommended to read the 'Stability Considerations'
-section in the qmp-commands.txt file before making any serious use of QMP.
-
-
-[1] http://www.json.org
-
-Usage
------
-
-To enable QMP, you need a QEMU monitor instance in "control mode". There are
-two ways of doing this.
-
-The simplest one is using the '-qmp' command-line option. The following
-example makes QMP available on localhost port 4444:
-
- $ qemu [...] -qmp tcp:localhost:4444,server
-
-However, in order to have more complex combinations, like multiple monitors,
-the '-mon' command-line option should be used along with the '-chardev' one.
-For instance, the following example creates one user monitor on stdio and one
-QMP monitor on localhost port 4444.
-
- $ qemu [...] -chardev stdio,id=mon0 -mon chardev=mon0,mode=readline \
- -chardev socket,id=mon1,host=localhost,port=4444,server \
- -mon chardev=mon1,mode=control
-
-Please, refer to QEMU's manpage for more information.
-
-Simple Testing
---------------
-
-To manually test QMP one can connect with telnet and issue commands by hand:
-
-$ telnet localhost 4444
-Trying 127.0.0.1...
-Connected to localhost.
-Escape character is '^]'.
-{"QMP": {"version": {"qemu": {"micro": 50, "minor": 13, "major": 0}, "package": ""}, "capabilities": []}}
-{ "execute": "qmp_capabilities" }
-{"return": {}}
-{ "execute": "query-version" }
-{"return": {"qemu": {"micro": 50, "minor": 13, "major": 0}, "package": ""}}
-
-Development Process
--------------------
-
-When changing QMP's interface (by adding new commands, events or modifying
-existing ones) it's mandatory to update the relevant documentation, which is
-one (or more) of the files listed in the 'Introduction' section*.
-
-Also, it's strongly recommended to send the documentation patch first, before
-doing any code change. This is so because:
-
- 1. Avoids the code dictating the interface
-
- 2. Review can improve your interface. Letting that happen before
- you implement it can save you work.
-
-* The qmp-commands.txt file is generated from the qmp-commands.hx one, which
- is the file that should be edited.
-
-Homepage
---------
-
-http://wiki.qemu.org/QMP
diff --git a/QMP/qmp-events.txt b/QMP/qmp-events.txt
deleted file mode 100644
index 4b24ec900d..0000000000
--- a/QMP/qmp-events.txt
+++ /dev/null
@@ -1,502 +0,0 @@
- QEMU Monitor Protocol Events
- ============================
-
-BALLOON_CHANGE
---------------
-
-Emitted when the guest changes the actual BALLOON level. This
-value is equivalent to the 'actual' field return by the
-'query-balloon' command
-
-Data:
-
-- "actual": actual level of the guest memory balloon in bytes (json-number)
-
-Example:
-
-{ "event": "BALLOON_CHANGE",
- "data": { "actual": 944766976 },
- "timestamp": { "seconds": 1267020223, "microseconds": 435656 } }
-
-BLOCK_IMAGE_CORRUPTED
----------------------
-
-Emitted when a disk image is being marked corrupt.
-
-Data:
-
-- "device": Device name (json-string)
-- "msg": Informative message (e.g., reason for the corruption) (json-string)
-- "offset": If the corruption resulted from an image access, this is the access
- offset into the image (json-int)
-- "size": If the corruption resulted from an image access, this is the access
- size (json-int)
-
-Example:
-
-{ "event": "BLOCK_IMAGE_CORRUPTED",
- "data": { "device": "ide0-hd0",
- "msg": "Prevented active L1 table overwrite", "offset": 196608,
- "size": 65536 },
- "timestamp": { "seconds": 1378126126, "microseconds": 966463 } }
-
-BLOCK_IO_ERROR
---------------
-
-Emitted when a disk I/O error occurs.
-
-Data:
-
-- "device": device name (json-string)
-- "operation": I/O operation (json-string, "read" or "write")
-- "action": action that has been taken, it's one of the following (json-string):
- "ignore": error has been ignored
- "report": error has been reported to the device
- "stop": error caused VM to be stopped
-
-Example:
-
-{ "event": "BLOCK_IO_ERROR",
- "data": { "device": "ide0-hd1",
- "operation": "write",
- "action": "stop" },
- "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
-
-Note: If action is "stop", a STOP event will eventually follow the
-BLOCK_IO_ERROR event.
-
-BLOCK_JOB_CANCELLED
--------------------
-
-Emitted when a block job has been cancelled.
-
-Data:
-
-- "type": Job type (json-string; "stream" for image streaming
- "commit" for block commit)
-- "device": Device name (json-string)
-- "len": Maximum progress value (json-int)
-- "offset": Current progress value (json-int)
- On success this is equal to len.
- On failure this is less than len.
-- "speed": Rate limit, bytes per second (json-int)
-
-Example:
-
-{ "event": "BLOCK_JOB_CANCELLED",
- "data": { "type": "stream", "device": "virtio-disk0",
- "len": 10737418240, "offset": 134217728,
- "speed": 0 },
- "timestamp": { "seconds": 1267061043, "microseconds": 959568 } }
-
-BLOCK_JOB_COMPLETED
--------------------
-
-Emitted when a block job has completed.
-
-Data:
-
-- "type": Job type (json-string; "stream" for image streaming
- "commit" for block commit)
-- "device": Device name (json-string)
-- "len": Maximum progress value (json-int)
-- "offset": Current progress value (json-int)
- On success this is equal to len.
- On failure this is less than len.
-- "speed": Rate limit, bytes per second (json-int)
-- "error": Error message (json-string, optional)
- 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.
-
-Example:
-
-{ "event": "BLOCK_JOB_COMPLETED",
- "data": { "type": "stream", "device": "virtio-disk0",
- "len": 10737418240, "offset": 10737418240,
- "speed": 0 },
- "timestamp": { "seconds": 1267061043, "microseconds": 959568 } }
-
-BLOCK_JOB_ERROR
----------------
-
-Emitted when a block job encounters an error.
-
-Data:
-
-- "device": device name (json-string)
-- "operation": I/O operation (json-string, "read" or "write")
-- "action": action that has been taken, it's one of the following (json-string):
- "ignore": error has been ignored, the job may fail later
- "report": error will be reported and the job canceled
- "stop": error caused job to be paused
-
-Example:
-
-{ "event": "BLOCK_JOB_ERROR",
- "data": { "device": "ide0-hd1",
- "operation": "write",
- "action": "stop" },
- "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
-
-BLOCK_JOB_READY
----------------
-
-Emitted when a block job is ready to complete.
-
-Data:
-
-- "device": device name (json-string)
-
-Example:
-
-{ "event": "BLOCK_JOB_READY",
- "data": { "device": "ide0-hd1" },
- "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
-
-Note: The "ready to complete" status is always reset by a BLOCK_JOB_ERROR
-event.
-
-DEVICE_DELETED
------------------
-
-Emitted whenever the device removal completion is acknowledged
-by the guest.
-At this point, it's safe to reuse the specified device ID.
-Device removal can be initiated by the guest or by HMP/QMP commands.
-
-Data:
-
-- "device": device name (json-string, optional)
-- "path": device path (json-string)
-
-{ "event": "DEVICE_DELETED",
- "data": { "device": "virtio-net-pci-0",
- "path": "/machine/peripheral/virtio-net-pci-0" },
- "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
-
-DEVICE_TRAY_MOVED
------------------
-
-It's emitted whenever the tray of a removable device is moved by the guest
-or by HMP/QMP commands.
-
-Data:
-
-- "device": device name (json-string)
-- "tray-open": true if the tray has been opened or false if it has been closed
- (json-bool)
-
-{ "event": "DEVICE_TRAY_MOVED",
- "data": { "device": "ide1-cd0",
- "tray-open": true
- },
- "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
-
-NIC_RX_FILTER_CHANGED
------------------
-
-The event is emitted once until the query command is executed,
-the first event will always be emitted.
-
-Data:
-
-- "name": net client name (json-string)
-- "path": device path (json-string)
-
-{ "event": "NIC_RX_FILTER_CHANGED",
- "data": { "name": "vnet0",
- "path": "/machine/peripheral/vnet0/virtio-backend" },
- "timestamp": { "seconds": 1368697518, "microseconds": 326866 } }
-}
-
-RESET
------
-
-Emitted when the Virtual Machine is reseted.
-
-Data: None.
-
-Example:
-
-{ "event": "RESET",
- "timestamp": { "seconds": 1267041653, "microseconds": 9518 } }
-
-RESUME
-------
-
-Emitted when the Virtual Machine resumes execution.
-
-Data: None.
-
-Example:
-
-{ "event": "RESUME",
- "timestamp": { "seconds": 1271770767, "microseconds": 582542 } }
-
-RTC_CHANGE
-----------
-
-Emitted when the guest changes the RTC time.
-
-Data:
-
-- "offset": Offset between base RTC clock (as specified by -rtc base), and
-new RTC clock value (json-number)
-
-Example:
-
-{ "event": "RTC_CHANGE",
- "data": { "offset": 78 },
- "timestamp": { "seconds": 1267020223, "microseconds": 435656 } }
-
-SHUTDOWN
---------
-
-Emitted when the Virtual Machine is powered down.
-
-Data: None.
-
-Example:
-
-{ "event": "SHUTDOWN",
- "timestamp": { "seconds": 1267040730, "microseconds": 682951 } }
-
-Note: If the command-line option "-no-shutdown" has been specified, a STOP
-event will eventually follow the SHUTDOWN event.
-
-SPICE_CONNECTED, SPICE_DISCONNECTED
------------------------------------
-
-Emitted when a SPICE client connects or disconnects.
-
-Data:
-
-- "server": Server information (json-object)
- - "host": IP address (json-string)
- - "port": port number (json-string)
- - "family": address family (json-string, "ipv4" or "ipv6")
-- "client": Client information (json-object)
- - "host": IP address (json-string)
- - "port": port number (json-string)
- - "family": address family (json-string, "ipv4" or "ipv6")
-
-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"}
-}}
-
-SPICE_INITIALIZED
------------------
-
-Emitted after initial handshake and authentication takes place (if any)
-and the SPICE channel is up'n'running
-
-Data:
-
-- "server": Server information (json-object)
- - "host": IP address (json-string)
- - "port": port number (json-string)
- - "family": address family (json-string, "ipv4" or "ipv6")
- - "auth": authentication method (json-string, optional)
-- "client": Client information (json-object)
- - "host": IP address (json-string)
- - "port": port number (json-string)
- - "family": address family (json-string, "ipv4" or "ipv6")
- - "connection-id": spice connection id. All channels with the same id
- belong to the same spice session (json-int)
- - "channel-type": channel type. "1" is the main control channel, filter for
- this one if you want track spice sessions only (json-int)
- - "channel-id": channel id. Usually "0", might be different needed when
- multiple channels of the same type exist, such as multiple
- display channels in a multihead setup (json-int)
- - "tls": whevener the channel is encrypted (json-bool)
-
-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}
-}}
-
-STOP
-----
-
-Emitted when the Virtual Machine is stopped.
-
-Data: None.
-
-Example:
-
-{ "event": "STOP",
- "timestamp": { "seconds": 1267041730, "microseconds": 281295 } }
-
-SUSPEND
--------
-
-Emitted when guest enters S3 state.
-
-Data: None.
-
-Example:
-
-{ "event": "SUSPEND",
- "timestamp": { "seconds": 1344456160, "microseconds": 309119 } }
-
-SUSPEND_DISK
-------------
-
-Emitted when the guest makes a request to enter S4 state.
-
-Data: None.
-
-Example:
-
-{ "event": "SUSPEND_DISK",
- "timestamp": { "seconds": 1344456160, "microseconds": 309119 } }
-
-Note: QEMU shuts down when entering S4 state.
-
-VNC_CONNECTED
--------------
-
-Emitted when a VNC client establishes a connection.
-
-Data:
-
-- "server": Server information (json-object)
- - "host": IP address (json-string)
- - "service": port number (json-string)
- - "family": address family (json-string, "ipv4" or "ipv6")
- - "auth": authentication method (json-string, optional)
-- "client": Client information (json-object)
- - "host": IP address (json-string)
- - "service": port number (json-string)
- - "family": address family (json-string, "ipv4" or "ipv6")
-
-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 } }
-
-
-Note: This event is emitted before any authentication takes place, thus
-the authentication ID is not provided.
-
-VNC_DISCONNECTED
-----------------
-
-Emitted when the connection is closed.
-
-Data:
-
-- "server": Server information (json-object)
- - "host": IP address (json-string)
- - "service": port number (json-string)
- - "family": address family (json-string, "ipv4" or "ipv6")
- - "auth": authentication method (json-string, optional)
-- "client": Client information (json-object)
- - "host": IP address (json-string)
- - "service": port number (json-string)
- - "family": address family (json-string, "ipv4" or "ipv6")
- - "x509_dname": TLS dname (json-string, optional)
- - "sasl_username": SASL username (json-string, optional)
-
-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 } }
-
-VNC_INITIALIZED
----------------
-
-Emitted after authentication takes place (if any) and the VNC session is
-made active.
-
-Data:
-
-- "server": Server information (json-object)
- - "host": IP address (json-string)
- - "service": port number (json-string)
- - "family": address family (json-string, "ipv4" or "ipv6")
- - "auth": authentication method (json-string, optional)
-- "client": Client information (json-object)
- - "host": IP address (json-string)
- - "service": port number (json-string)
- - "family": address family (json-string, "ipv4" or "ipv6")
- - "x509_dname": TLS dname (json-string, optional)
- - "sasl_username": SASL username (json-string, optional)
-
-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 } }
-
-WAKEUP
-------
-
-Emitted when the guest has woken up from S3 and is running.
-
-Data: None.
-
-Example:
-
-{ "event": "WATCHDOG",
- "timestamp": { "seconds": 1344522075, "microseconds": 745528 } }
-
-WATCHDOG
---------
-
-Emitted when the watchdog device's timer is expired.
-
-Data:
-
-- "action": Action that has been taken, it's one of the following (json-string):
- "reset", "shutdown", "poweroff", "pause", "debug", or "none"
-
-Example:
-
-{ "event": "WATCHDOG",
- "data": { "action": "reset" },
- "timestamp": { "seconds": 1267061043, "microseconds": 959568 } }
-
-Note: If action is "reset", "shutdown", or "pause" the WATCHDOG event is
-followed respectively by the RESET, SHUTDOWN, or STOP events.
-
-GUEST_PANICKED
---------------
-
-Emitted when guest OS panic is detected.
-
-Data:
-
-- "action": Action that has been taken (json-string, currently always "pause").
-
-Example:
-
-{ "event": "GUEST_PANICKED",
- "data": { "action": "pause" } }
diff --git a/QMP/qmp-spec.txt b/QMP/qmp-spec.txt
deleted file mode 100644
index a27789692b..0000000000
--- a/QMP/qmp-spec.txt
+++ /dev/null
@@ -1,282 +0,0 @@
- QEMU Monitor Protocol Specification - Version 0.1
-
-1. Introduction
-===============
-
-This document specifies the QEMU Monitor Protocol (QMP), a JSON-based protocol
-which is available for applications to control QEMU at the machine-level.
-
-To enable QMP support, QEMU has to be run in "control mode". This is done by
-starting QEMU with the appropriate command-line options. Please, refer to the
-QEMU manual page for more information.
-
-2. Protocol Specification
-=========================
-
-This section details the protocol format. For the purpose of this document
-"Client" is any application which is communicating with QEMU in control mode,
-and "Server" is QEMU itself.
-
-JSON data structures, when mentioned in this document, are always in the
-following format:
-
- json-DATA-STRUCTURE-NAME
-
-Where DATA-STRUCTURE-NAME is any valid JSON data structure, as defined by
-the JSON standard:
-
-http://www.ietf.org/rfc/rfc4627.txt
-
-For convenience, json-object members and json-array elements mentioned in
-this document will be in a certain order. However, in real protocol usage
-they can be in ANY order, thus no particular order should be assumed.
-
-2.1 General Definitions
------------------------
-
-2.1.1 All interactions transmitted by the Server are json-objects, always
- terminating with CRLF
-
-2.1.2 All json-objects members are mandatory when not specified otherwise
-
-2.2 Server Greeting
--------------------
-
-Right when connected the Server will issue a greeting message, which signals
-that the connection has been successfully established and that the Server is
-ready for capabilities negotiation (for more information refer to section
-'4. Capabilities Negotiation').
-
-The format is:
-
-{ "QMP": { "version": json-object, "capabilities": json-array } }
-
- Where,
-
-- The "version" member contains the Server's version information (the format
- is the same of the 'query-version' command)
-- The "capabilities" member specify the availability of features beyond the
- baseline specification
-
-2.3 Issuing Commands
---------------------
-
-The format for command execution is:
-
-{ "execute": json-string, "arguments": json-object, "id": json-value }
-
- Where,
-
-- The "execute" member identifies the command to be executed by the Server
-- The "arguments" member is used to pass any arguments required for the
- execution of the command, it is optional when no arguments are required
-- The "id" member is a transaction identification associated with the
- command execution, it is optional and will be part of the response if
- provided
-
-2.4 Commands Responses
-----------------------
-
-There are two possible responses which the Server will issue as the result
-of a command execution: success or error.
-
-2.4.1 success
--------------
-
-The success response is issued when the command execution has finished
-without errors.
-
-The format is:
-
-{ "return": json-object, "id": json-value }
-
- Where,
-
-- The "return" member contains the command returned data, which is defined
- in a per-command basis or an empty json-object if the command does not
- return data
-- The "id" member contains the transaction identification associated
- with the command execution (if issued by the Client)
-
-2.4.2 error
------------
-
-The error response is issued when the command execution could not be
-completed because of an error condition.
-
-The format is:
-
-{ "error": { "class": json-string, "desc": json-string }, "id": json-value }
-
- Where,
-
-- The "class" member contains the error class name (eg. "GenericError")
-- The "desc" member is a human-readable error message. Clients should
- not attempt to parse this message.
-- The "id" member contains the transaction identification associated with
- the command execution (if issued by the Client)
-
-NOTE: Some errors can occur before the Server is able to read the "id" member,
-in these cases the "id" member will not be part of the error response, even
-if provided by the client.
-
-2.5 Asynchronous events
------------------------
-
-As a result of state changes, the Server may send messages unilaterally
-to the Client at any time. They are called 'asynchronous events'.
-
-The format is:
-
-{ "event": json-string, "data": json-object,
- "timestamp": { "seconds": json-number, "microseconds": json-number } }
-
- Where,
-
-- The "event" member contains the event's name
-- The "data" member contains event specific data, which is defined in a
- per-event basis, it is optional
-- The "timestamp" member contains the exact time of when the event occurred
- in the Server. It is a fixed json-object with time in seconds and
- microseconds
-
-For a listing of supported asynchronous events, please, refer to the
-qmp-events.txt file.
-
-3. QMP Examples
-===============
-
-This section provides some examples of real QMP usage, in all of them
-'C' stands for 'Client' and 'S' stands for 'Server'.
-
-3.1 Server greeting
--------------------
-
-S: {"QMP": {"version": {"qemu": "0.12.50", "package": ""}, "capabilities": []}}
-
-3.2 Simple 'stop' execution
----------------------------
-
-C: { "execute": "stop" }
-S: {"return": {}}
-
-3.3 KVM information
--------------------
-
-C: { "execute": "query-kvm", "id": "example" }
-S: {"return": {"enabled": true, "present": true}, "id": "example"}
-
-3.4 Parsing error
-------------------
-
-C: { "execute": }
-S: {"error": {"class": "GenericError", "desc": "Invalid JSON syntax" } }
-
-3.5 Powerdown event
--------------------
-
-S: {"timestamp": {"seconds": 1258551470, "microseconds": 802384}, "event":
-"POWERDOWN"}
-
-4. Capabilities Negotiation
-----------------------------
-
-When a Client successfully establishes a connection, the Server is in
-Capabilities Negotiation mode.
-
-In this mode only the 'qmp_capabilities' command is allowed to run, all
-other commands will return the CommandNotFound error. Asynchronous messages
-are not delivered either.
-
-Clients should use the 'qmp_capabilities' command to enable capabilities
-advertised in the Server's greeting (section '2.2 Server Greeting') they
-support.
-
-When the 'qmp_capabilities' command is issued, and if it does not return an
-error, the Server enters in Command mode where capabilities changes take
-effect, all commands (except 'qmp_capabilities') are allowed and asynchronous
-messages are delivered.
-
-5 Compatibility Considerations
-------------------------------
-
-All protocol changes or new features which modify the protocol format in an
-incompatible way are disabled by default and will be advertised by the
-capabilities array (section '2.2 Server Greeting'). Thus, Clients can check
-that array and enable the capabilities they support.
-
-The QMP Server performs a type check on the arguments to a command. It
-generates an error if a value does not have the expected type for its
-key, or if it does not understand a key that the Client included. The
-strictness of the Server catches wrong assumptions of Clients about
-the Server's schema. Clients can assume that, when such validation
-errors occur, they will be reported before the command generated any
-side effect.
-
-However, Clients must not assume any particular:
-
-- Length of json-arrays
-- Size of json-objects; in particular, future versions of QEMU may add
- new keys and Clients should be able to ignore them.
-- Order of json-object members or json-array elements
-- Amount of errors generated by a command, that is, new errors can be added
- to any existing command in newer versions of the Server
-
-Of course, the Server does guarantee to send valid JSON. But apart from
-this, a Client should be "conservative in what they send, and liberal in
-what they accept".
-
-6. Downstream extension of QMP
-------------------------------
-
-We recommend that downstream consumers of QEMU do *not* modify QMP.
-Management tools should be able to support both upstream and downstream
-versions of QMP without special logic, and downstream extensions are
-inherently at odds with that.
-
-However, we recognize that it is sometimes impossible for downstreams to
-avoid modifying QMP. Both upstream and downstream need to take care to
-preserve long-term compatibility and interoperability.
-
-To help with that, QMP reserves JSON object member names beginning with
-'__' (double underscore) for downstream use ("downstream names"). This
-means upstream will never use any downstream names for its commands,
-arguments, errors, asynchronous events, and so forth.
-
-Any new names downstream wishes to add must begin with '__'. To
-ensure compatibility with other downstreams, it is strongly
-recommended that you prefix your downstram names with '__RFQDN_' where
-RFQDN is a valid, reverse fully qualified domain name which you
-control. For example, a qemu-kvm specific monitor command would be:
-
- (qemu) __org.linux-kvm_enable_irqchip
-
-Downstream must not change the server greeting (section 2.2) other than
-to offer additional capabilities. But see below for why even that is
-discouraged.
-
-Section '5 Compatibility Considerations' applies to downstream as well
-as to upstream, obviously. It follows that downstream must behave
-exactly like upstream for any input not containing members with
-downstream names ("downstream members"), except it may add members
-with downstream names to its output.
-
-Thus, a client should not be able to distinguish downstream from
-upstream as long as it doesn't send input with downstream members, and
-properly ignores any downstream members in the output it receives.
-
-Advice on downstream modifications:
-
-1. Introducing new commands is okay. If you want to extend an existing
- command, consider introducing a new one with the new behaviour
- instead.
-
-2. Introducing new asynchronous messages is okay. If you want to extend
- an existing message, consider adding a new one instead.
-
-3. Introducing new errors for use in new commands is okay. Adding new
- errors to existing commands counts as extension, so 1. applies.
-
-4. New capabilities are strongly discouraged. Capabilities are for
- evolving the basic protocol, and multiple diverging basic protocol
- dialects are most undesirable.