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authorYang Zhang <yang.z.zhang@intel.com>2015-08-28 09:58:54 +0800
committerYang Zhang <yang.z.zhang@intel.com>2015-09-01 12:44:00 +0800
commite44e3482bdb4d0ebde2d8b41830ac2cdb07948fb (patch)
tree66b09f592c55df2878107a468a91d21506104d3f /qemu/docs/qmp
parent9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (diff)
Add qemu 2.4.0
Change-Id: Ic99cbad4b61f8b127b7dc74d04576c0bcbaaf4f5 Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>
Diffstat (limited to 'qemu/docs/qmp')
-rw-r--r--qemu/docs/qmp/README87
-rw-r--r--qemu/docs/qmp/qmp-events.txt664
-rw-r--r--qemu/docs/qmp/qmp-spec.txt336
3 files changed, 1087 insertions, 0 deletions
diff --git a/qemu/docs/qmp/README b/qemu/docs/qmp/README
new file mode 100644
index 000000000..f6a3a031e
--- /dev/null
+++ b/qemu/docs/qmp/README
@@ -0,0 +1,87 @@
+ QEMU Machine Protocol
+ =====================
+
+Introduction
+------------
+
+The QEMU Machine Protocol (QMP) allows applications to operate a
+QEMU instance.
+
+QMP is JSON[1] based and features the following:
+
+- 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 Machine Protocol current specification
+o qmp-commands.txt QMP supported commands (auto-generated at build-time)
+o qmp-events.txt List of available asynchronous events
+
+[1] http://www.json.org
+
+Usage
+-----
+
+You can use the -qmp option to enable QMP. For example, the following
+makes QMP available on localhost port 4444:
+
+$ qemu [...] -qmp tcp:localhost:4444,server,nowait
+
+However, for more flexibility and to make use of more options, the -mon
+command-line option should be used. For instance, the following example
+creates one HMP instance (human monitor) on stdio and one QMP instance
+on localhost port 4444:
+
+$ qemu [...] -chardev stdio,id=mon0 -mon chardev=mon0,mode=readline \
+ -chardev socket,id=mon1,host=localhost,port=4444,server,nowait \
+ -mon chardev=mon1,mode=control,pretty=on
+
+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": 6,
+ "major": 1
+ },
+ "package": ""
+ },
+ "capabilities": [
+ ]
+ }
+}
+
+{ "execute": "qmp_capabilities" }
+{
+ "return": {
+ }
+}
+
+{ "execute": "query-status" }
+{
+ "return": {
+ "status": "prelaunch",
+ "singlestep": false,
+ "running": false
+ }
+}
+
+Please, refer to the qapi-schema.json file for a complete command reference.
+
+QMP wiki page
+-------------
+
+http://wiki.qemu-project.org/QMP
diff --git a/qemu/docs/qmp/qmp-events.txt b/qemu/docs/qmp/qmp-events.txt
new file mode 100644
index 000000000..d92cc4833
--- /dev/null
+++ b/qemu/docs/qmp/qmp-events.txt
@@ -0,0 +1,664 @@
+ QEMU Machine Protocol Events
+ ============================
+
+ACPI_DEVICE_OST
+---------------
+
+Emitted when guest executes ACPI _OST method.
+
+ - data: ACPIOSTInfo type as described in qapi-schema.json
+
+{ "event": "ACPI_DEVICE_OST",
+ "data": { "device": "d1", "slot": "0", "slot-type": "DIMM", "source": 1, "status": 0 } }
+
+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. 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.
+
+Data:
+
+- "device": Device name (json-string)
+- "node-name": Node name (json-string, optional)
+- "msg": Informative message (e.g., reason for the corruption)
+ (json-string)
+- "offset": If the corruption resulted from an image access, this
+ is the host's access offset into the image
+ (json-int, optional)
+- "size": If the corruption resulted from an image access, this
+ is the access size (json-int, optional)
+
+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 } }
+
+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": the VM is going to stop because of the error
+
+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:
+
+- "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_READY",
+ "data": { "device": "drive0", "type": "mirror", "speed": 0,
+ "len": 2097152, "offset": 2097152 }
+ "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 } }
+
+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" } }
+
+MEM_UNPLUG_ERROR
+--------------------
+Emitted when memory hot unplug error occurs.
+
+Data:
+
+- "device": device name (json-string)
+- "msg": Informative message (e.g., reason for the error) (json-string)
+
+Example:
+
+{ "event": "MEM_UNPLUG_ERROR"
+ "data": { "device": "dimm1",
+ "msg": "acpi: device unplug for unsupported device"
+ },
+ "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 } }
+}
+
+POWERDOWN
+---------
+
+Emitted when the Virtual Machine is powered down through the power
+control system, such as via ACPI.
+
+Data: None.
+
+Example:
+
+{ "event": "POWERDOWN",
+ "timestamp": { "seconds": 1267040730, "microseconds": 682951 } }
+
+QUORUM_FAILURE
+--------------
+
+Emitted by the Quorum block driver if it fails to establish a quorum.
+
+Data:
+
+- "reference": device name if defined else node name.
+- "sector-num": Number of the first sector of the failed read operation.
+- "sectors-count": Failed read operation sector count.
+
+Example:
+
+{ "event": "QUORUM_FAILURE",
+ "data": { "reference": "usr1", "sector-num": 345435, "sectors-count": 5 },
+ "timestamp": { "seconds": 1344522075, "microseconds": 745528 } }
+
+QUORUM_REPORT_BAD
+-----------------
+
+Emitted to report a corruption of a Quorum file.
+
+Data:
+
+- "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 the
+ block layer reported an error and clients should not try to
+ interpret the error string.
+- "node-name": The graph node name of the block driver state.
+- "sector-num": Number of the first sector of the failed read operation.
+- "sectors-count": Failed read operation sector count.
+
+Example:
+
+{ "event": "QUORUM_REPORT_BAD",
+ "data": { "node-name": "1.raw", "sector-num": 345435, "sectors-count": 5 },
+ "timestamp": { "seconds": 1344522075, "microseconds": 745528 } }
+
+RESET
+-----
+
+Emitted when the Virtual Machine is reset.
+
+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 has shut down, indicating that qemu
+is about to exit.
+
+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
+---------------
+
+Emitted when a SPICE client connects.
+
+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_DISCONNECTED
+------------------
+
+Emitted when a SPICE client 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_DISCONNECTED",
+ "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 and 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}
+}}
+
+SPICE_MIGRATE_COMPLETED
+-----------------------
+
+Emitted when SPICE migration has completed
+
+Data: None.
+
+Example:
+
+{ "timestamp": {"seconds": 1290688046, "microseconds": 417172},
+ "event": "SPICE_MIGRATE_COMPLETED" }
+
+MIGRATION
+---------
+
+Emitted when a migration event happens
+
+Data: None.
+
+ - "status": migration status
+ See MigrationStatus in ~/qapi-schema.json for possible values
+
+Example:
+
+{"timestamp": {"seconds": 1432121972, "microseconds": 744001},
+ "event": "MIGRATION", "data": {"status": "completed"}}
+
+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 } }
+
+VSERPORT_CHANGE
+---------------
+
+Emitted when the guest opens or closes a virtio-serial port.
+
+Data:
+
+- "id": device identifier of the virtio-serial port (json-string)
+- "open": true if the guest has opened the virtio-serial port (json-bool)
+
+Example:
+
+{ "event": "VSERPORT_CHANGE",
+ "data": { "id": "channel0", "open": true },
+ "timestamp": { "seconds": 1401385907, "microseconds": 422329 } }
+
+WAKEUP
+------
+
+Emitted when the guest has woken up from S3 and is running.
+
+Data: None.
+
+Example:
+
+{ "event": "WAKEUP",
+ "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.
diff --git a/qemu/docs/qmp/qmp-spec.txt b/qemu/docs/qmp/qmp-spec.txt
new file mode 100644
index 000000000..4c28cd943
--- /dev/null
+++ b/qemu/docs/qmp/qmp-spec.txt
@@ -0,0 +1,336 @@
+ QEMU Machine Protocol Specification
+
+0. About This Document
+======================
+
+Copyright (C) 2009-2015 Red Hat, Inc.
+
+This work is licensed under the terms of the GNU GPL, version 2 or
+later. See the COPYING file in the top-level directory.
+
+1. Introduction
+===============
+
+This document specifies the QEMU Machine Protocol (QMP), a JSON-based
+protocol which is available for applications to operate QEMU at the
+machine-level. It is also in use by the QEMU Guest Agent (QGA), which
+is available for host applications to interact with the guest
+operating system.
+
+2. Protocol Specification
+=========================
+
+This section details the protocol format. For the purpose of this document
+"Client" is any application which is using QMP to communicate with QEMU 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/rfc7159.txt
+
+The protocol is always encoded in UTF-8 except for synchronization
+bytes (documented below); although thanks to json-string escape
+sequences, the server will reply using only the strict ASCII subset.
+
+For convenience, json-object members 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. On the other
+hand, use of json-array elements presumes that preserving order is
+important unless specifically documented otherwise. Repeating a key
+within a json-object gives unpredictable results.
+
+Also for convenience, the server will accept an extension of
+'single-quoted' strings in place of the usual "double-quoted"
+json-string, and both input forms of strings understand an additional
+escape sequence of "\'" for a single quote. The server will only use
+double quoting on output.
+
+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 greeting message 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; the order of elements in this array has no
+ particular significance, so a client must search the entire array
+ when looking for a particular capability
+
+2.2.1 Capabilities
+------------------
+
+As of the date this document was last revised, no server or client
+capability strings have been defined.
+
+
+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. Each command documents what contents will be considered
+ valid when handling the json-argument
+- The "id" member is a transaction identification associated with the
+ command execution, it is optional and will be part of the response if
+ provided. The "id" member can be any json-value, although most
+ clients merely use a json-number incremented for each successive
+ command
+
+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 format of a success response is:
+
+{ "return": json-value, "id": json-value }
+
+ Where,
+
+- The "return" member contains the data returned by the command, which
+ is defined on a per-command basis (usually a json-object or
+ json-array of json-objects, but sometimes a json-number, json-string,
+ or json-array of json-strings); it is 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 format of an error response 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, when not in the middle of any other
+response. They are called "asynchronous events".
+
+The format of asynchronous events 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 relative to the Unix Epoch (1 Jan 1970); if
+ there is a failure to retrieve host time, both members of the
+ timestamp will be set to -1.
+
+For a listing of supported asynchronous events, please, refer to the
+qmp-events.txt file.
+
+2.5 QGA Synchronization
+-----------------------
+
+When using QGA, an additional synchronization feature is built into
+the protocol. If the Client sends a raw 0xFF sentinel byte (not valid
+JSON), then the Server will reset its state and discard all pending
+data prior to the sentinel. Conversely, if the Client makes use of
+the 'guest-sync-delimited' command, the Server will send a raw 0xFF
+sentinel byte prior to its response, to aid the Client in discarding
+any data prior to the sentinel.
+
+
+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": { "micro": 50, "minor": 6, "major": 1 },
+ "package": ""}, "capabilities": []}}
+
+3.2 Client QMP negotiation
+--------------------------
+C: { "execute": "qmp_capabilities" }
+S: { "return": {}}
+
+3.3 Simple 'stop' execution
+---------------------------
+
+C: { "execute": "stop" }
+S: { "return": {} }
+
+3.4 KVM information
+-------------------
+
+C: { "execute": "query-kvm", "id": "example" }
+S: { "return": { "enabled": true, "present": true }, "id": "example"}
+
+3.5 Parsing error
+------------------
+
+C: { "execute": }
+S: { "error": { "class": "GenericError", "desc": "Invalid JSON syntax" } }
+
+3.6 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
+
+Any command or field name beginning with "x-" is deemed experimental,
+and may be withdrawn or changed in an incompatible manner in a future
+release.
+
+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 downstream 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.