[Qemu-devel] [PATCH V7 0/5] Send the gratuitous by guest

[Jason Wang <jasowang@redhat.com>]

This series tries to let guest instead of qemu to send the gratuitous packets
after migration when guest is capable of doing this. This is needed since it's
impossible for qemu to keep track of all configurations (e.g 802.1Q) and mac
addresses (more than one mac address may be used by guest). So qemu can't build
gratuitous packets for all those configurations properly. The only solution is
let guest driver who knew all needed information to do this.

The series first introduces a new runstate which just tracks the state when the
migration is finished and guest is about to start. And then we can just trying
to notify the guest to send the GARP after changing from this state to
running. A model specific announcing method were also also introduced to let
each kinds of nic do its own notification. When there's no such method register
for the nic, the old style of sending RARP were kept. And the last two patches
implemented the virtio-net method of notification.

Changes from V6:
- introduce a new runstate instead of using a global variable check the state

Changes from V5:
- use a global variable to decide whether an announcement is needed after migration
- align with virtio spec and let guest ack the announcement notification through
  control vq instead of config status writing

Changes from V4:
- keep the old behavior that send the gratuitous packets only after migration
- decide whether to send gratuitous packets by previous runstate instead of a dedicated parameter
- check virtio_net_started() instead of VIRTIO_NET_S_LINK_UP before issue the config update interrupt
- move VIRTIO_NET_S_ANNOUNCE to 0x100 and supress guest config write to RO bits
- cleanups suggested by Michael

Tested with migration within 802.1Q.

Jason Wang (5):
  runstate: introduce prelaunch-migrate state
  net: announce self after vm is started
  net: model specific announcing support
  virtio-net: notify guest to annouce itself
  virtio-net: compat guest announce

 hw/pc.h           |    6 +++++-
 hw/virtio-net.c   |   30 ++++++++++++++++++++++++++++++
 hw/virtio-net.h   |   15 ++++++++++++++-
 include/net/net.h |    2 ++
 migration.c       |    4 +---
 qapi-schema.json  |    5 ++++-
 savevm.c          |    8 ++++++--
 vl.c              |    8 +++++++-
 8 files changed, 69 insertions(+), 9 deletions(-)