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![]() Currently macvtap based macvlan device is working in promiscuous mode, we want to implement mac-programming over macvtap through Libvirt for better performance. Design: QEMU notifies Libvirt when rx-filter config is changed in guest, then Libvirt query the rx-filter information by a monitor command, and sync the change to macvtap device. Related rx-filter config of the nic contains main mac, rx-mode items and vlan table. This patch adds a QMP event to notify management of rx-filter change, and adds a monitor command for management to query rx-filter information. Test: If we repeatedly add/remove vlan, and change macaddr of vlan interfaces in guest by a loop script. Result: The events will flood the QMP client(management), management takes too much resource to process the events. Event_throttle API (set rate to 1 ms) can avoid the events to flood QMP client, but it could cause an unexpected delay (~1ms), guests guests normally expect rx-filter updates immediately. So we use a flag for each nic to avoid events flooding, the event is emitted once until the query command is executed. The flag implementation could not introduce unexpected delay. There maybe exist an uncontrollable delay if we let Libvirt do the real change, guests normally expect rx-filter updates immediately. But it's another separate issue, we can investigate it when the work in Libvirt side is done. Michael S. Tsirkin: tweaked to enable events on start Michael S. Tsirkin: fixed not to crash when no id Michael S. Tsirkin: fold in patch: "additional fixes for mac-programming feature" Amos Kong: always notify QMP client if mactable is changed Amos Kong: return NULL list if no net client supports rx-filter query Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Amos Kong <akong@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> |
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qemu-ga-client | ||
qmp | ||
qmp-events.txt | ||
qmp-shell | ||
qmp-spec.txt | ||
qmp.py | ||
qom-fuse | ||
qom-get | ||
qom-list | ||
qom-set | ||
README |
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