Re: [Qemu-devel] [PATCH] virtio-net: support RSC v4/v6 tcp traffic for Windows HCK

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Nov 12, 2018 at 01:31:36PM +0200, Yuri Benditovich wrote:
> 
> 
> On Mon, Nov 12, 2018 at 11:26 AM Jason Wang <jasowang@redhat.com> wrote:
> 
> 
>     On 2018/11/12 下午4:57, Yuri Benditovich wrote:
>     >
>     > On Mon, Nov 12, 2018 at 4:54 AM Michael S. Tsirkin <mst@redhat.com
>     > <mailto:mst@redhat.com>> wrote:
>     >
>     >     On Sun, Nov 11, 2018 at 12:18:54PM +0200, Yuri Benditovich wrote:
>     >     >     > @@ -66,12 +143,16 @@ typedef struct VirtIONet {
>     >     >     >      VirtIONetQueue *vqs;
>     >     >     >      VirtQueue *ctrl_vq;
>     >     >     >      NICState *nic;
>     >     >     > +    QTAILQ_HEAD(, NetRscChain) rsc_chains;
>     >     >
>     >     >     what exactly happens with these chains on migration?
>     >     >
>     >     >
>     >     > This feature (software implementation of RSC in QEMU) is
>     >     intended to be used in
>     >     > the environment of certification tests which never uses migration.
>     >
>     >     Should this feature disable migration then?
>     >
>     >
>     > IMO, this should not. But if you find it mandatory, please respond and
>     > I will add the migration blocker.
> 
> 
>     So if my understanding is correct, it's safe to do nothing even if we
>     allow migration for RSC?
> 
> 
> This does not create any unrecoverable failure (assertion, BSOD), although
> some data (coalesced parts of packets not delivered yet to guest) will be lost.

If guest has no way to detect none of these packets were ever
received by card, then I guess it's fine. Needs a
comment in case we start caring about packet loss around
migration.

> 
> 
>     Thanks
> 
> 
>