Documentation/QMP: Difference between revisions

From QEMU
No edit summary
No edit summary
Line 53: Line 53:
http://repo.or.cz/w/qemu/qmp-unstable.git
http://repo.or.cz/w/qemu/qmp-unstable.git


'''NOTE''': all branches in this repository are constantly ''rebased'' (master inclusive).
'''IMPORTANT''': all branches in this repository are constantly ''rebased'' (master inclusive).
 
== TODO ==
 
=== short term ===
 
* Decouple HMP and QMP
* Re-work the error infrastructure
* HMP passthrough via QMP
* Improve QMP testing (unit-tests, kvm-autoest and libvirt-TCK)
 
=== medium/long term ===
 
* Self-description & improved user documentation
* Begin adding sane commands
* Asynchronous commands support

Revision as of 19:12, 8 September 2010

QEMU Monitor Protocol

The QEMU Monitor Protocol (QMP) is a JSON-based protocol which allows applications to communicate with QEMU's Monitor the right way.

QMP's main features are:

  • Lightweight, text-based, easy to parse data format
  • Asynchronous messages support (ie. events)
  • Capabilities negotiation
  • API/ABI stability guarantees

Please, check the README file for more information.

General Status

A supported version of QMP is available since QEMU 0.13 (and a "feature preview" version in QEMU 0.12), however several commands in the current API have badly defined semantics.

This means that we will be introducing a deprecation policy soon. Users should always check QMP documentation as soon as a new release of QEMU is out, so that they don't run in the risk of using a deprecated command which may be removed in a future release.

Examples

In the following examples, 'C' stands for 'Client' and 'S' stands for 'Server'.

Server Greeting

S: { "QMP": { "version": { "qemu": { "micro": 50, "minor": 13, "major": 0 }, "package": "" }, "capabilities": []}}

Query version

C: { "execute": "query-status" }
S: { "return": { "singlestep": false, "running": true } }

Eject a medium

C: { "execute": "eject", "arguments": { "device": "ide1-cd0" } }
S: {"return": {}}

Asynchronous message

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


Development

Main developers are Luiz Capitulino and Markus Armbruster, but all QMP-related discussions happen on the qemu-devel mailing list.

Next features, hot fixes and other patches are stored in the QMP unstable repository:

http://repo.or.cz/w/qemu/qmp-unstable.git

IMPORTANT: all branches in this repository are constantly rebased (master inclusive).

TODO

short term

  • Decouple HMP and QMP
  • Re-work the error infrastructure
  • HMP passthrough via QMP
  • Improve QMP testing (unit-tests, kvm-autoest and libvirt-TCK)

medium/long term

  • Self-description & improved user documentation
  • Begin adding sane commands
  • Asynchronous commands support