On 03/07/2013 06:25 PM, Michael S. Tsirkin wrote: > On Thu, Mar 07, 2013 at 06:13:41PM +0800, Jason Wang wrote: >> On 03/07/2013 06:04 PM, Michael S. Tsirkin wrote: >>> On Thu, Mar 07, 2013 at 04:23:46PM +0800, Jason Wang wrote: >>>> 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. >>> Do we want to retry SELF_ANNOUNCE_ROUNDS? >> Yes, we do the announcement several times like in the past. >>>> 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 >>> I wonder why it's a sane thing to do. How about simply sending the event >>> after load? >> The aim is to limit the change of the behaviour to focus on migration. >> We may also need this after cont, > Hmm why after cont?
If we stop the vm for a long period, the mac will be missed in the forward table of the bridge also. >> and then maybe we can just do this >> unconditionally in vm_start(). > OK but then the new infrastructure we are adding will be dead code, > won't it? If we do this, there's no need to introduce a new state then. > > Can we do this simply using a post load hook for now? Maybe not, this means we may want to inject an interrupt to guest when vm is not running. >>>> - 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(-)
