Re: [RFC PATCH for 8.0 10/13] virtio-net: Migrate vhost inflight descriptors

[Jason Wang]

On Tue, Jan 17, 2023 at 5:02 AM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Wed, Dec 07, 2022 at 09:56:20AM +0100, Eugenio Perez Martin wrote:
> > > A dumb question, any reason we need bother with virtio-net? It looks
> > > to me it's not a must and would complicate migration compatibility.
> > >
> > > I guess virtio-blk is the better place.
> > >
> >
> > I'm fine to start with -blk, but if -net devices are processing
> > buffers out of order we have chances of losing descriptors too.
> >
> > We can wait for more feedback to prioritize correctly this though.
> >
> > Thanks!
>
> Traditionally vhost serialized everything when dropping the VQ.
> Would be interesting to hear from hardware vendors on whether
> it's hard or easy to do in hardware.

The feedback is some vendors will do the serialization while others are not.

> But I suspect all devices will want the capability eventually
> because why not, if we have the code let's just do it everywhere.

Yes, but it's more about priority/compatibility other than whether it
is needed. We want to let the migration work as earlier as possible
for vendor to test and try.

Thanks

>
> --
> MST
>