net: add support of mac-programming over macvtap in QEMU side

Enterprise / Virtualization / QEMU - Amos Kong [redhat.com] - 15 July 2013 13:23 UTC

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

b1be428 net: add support of mac-programming over macvtap in QEMU side
QMP/qmp-events.txt | 17 ++++++
hw/net/virtio-net.c | 133 +++++++++++++++++++++++++++++++++++++++++++--
include/monitor/monitor.h | 1 +
include/net/net.h | 3 +
monitor.c | 1 +
net/net.c | 48 ++++++++++++++++
qapi-schema.json | 76 ++++++++++++++++++++++++++
qmp-commands.hx | 63 +++++++++++++++++++++
8 files changed, 336 insertions(+), 6 deletions(-)

Upstream: git.qemu.org

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