| 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 qemu-qmp-ref.html QEMU QMP commands and events (auto-generated at build-time) |
| |
| [1] https://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 |
| ------------- |
| |
| https://wiki.qemu.org/QMP |