Re: [Qemu-devel] [PATCH RFC V2] virtio-net: announce self by guest

[Jason Wang <jasowang@redhat.com>]

On 05/12/2014 03:22 PM, Michael S. Tsirkin wrote:
> On Fri, Apr 11, 2014 at 10:54:47AM +0800, Jason Wang wrote:
>> > It's hard to track all mac addresses and their configurations (e.g
>> > vlan or ipv6) in qemu. Without those informations, it's impossible to
>> > build proper garp packet after migration. The only possible solution
>> > to this is let guest (who knew all configurations) to do this.
>> > 
>> > So, this patch introduces a new readonly config status bit of virtio-net,
>> > VIRTIO_NET_S_ANNOUNCE which is used to notify guest to announce
>> > presence of its link through config update interrupt.When guest has
>> > done the announcement, it should ack the notification through
>> > VIRTIO_NET_CTRL_ANNOUNCE_ACK cmd. This feature is negotiated by a new
>> > feature bit VIRTIO_NET_F_ANNOUNCE (which has already been supported by
>> > Linux guest).
>> > 
>> > During load, a counter of announcing rounds were set so that the after
>> > the vm is running it can trigger rounds of config interrupts to notify
>> > the guest to build and send the correct garps.
>> > 
>> > Reference:
>> > RFC v1: https://lists.gnu.org/archive/html/qemu-devel/2014-03/msg02648.html
>> > V7:     https://lists.gnu.org/archive/html/qemu-devel/2013-03/msg01127.html
>> > 
>> > Changes from RFC v1:
>> > - clean VIRTIO_NET_S_ANNOUNCE bit during reset
>> > - free announce timer during clean
>> > - make announce work for non-vhost case
>> > 
>> > Changes from V7:
>> > - Instead of introducing a global method for each kind of nic, this
>> >   version limits the changes to virtio-net itself.
>> > 
>> > Cc: Liuyongan <liuyongan@huawei.com>
>> > Cc: Amos Kong <akong@redhat.com>
>> > Signed-off-by: Jason Wang <jasowang@redhat.com>
> Looks good to me, but I think you should use
> QEMU_CLOCK_VIRTUAL: let's not change VM state
> when emulation is not running.
>

Sure, will post another version.

Thanks