Re: [PATCH 2/4] vhost-user: Interface for migration state transfer

[Eugenio Perez Martin]

On Tue, May 9, 2023 at 11:01 AM Hanna Czenczek <hreitz@redhat.com> wrote:
>
> On 09.05.23 08:31, Eugenio Perez Martin wrote:
> > On Mon, May 8, 2023 at 9:12 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
>
> [...]
>
> >> VHOST_USER_GET_VRING_BASE itself isn't really enough because it stops a
> >> specific virtqueue but not the whole device. Unfortunately stopping all
> >> virtqueues is not the same as SUSPEND since spontaneous device activity
> >> is possible independent of any virtqueue (e.g. virtio-scsi events and
> >> maybe virtio-net link status).
> >>
> >> That's why I think SUSPEND is necessary for a solution that's generic
> >> enough to cover all device types.
> >>
> > I agree.
> >
> > In particular virtiofsd is already resetting all the device at
> > VHOST_USER_GET_VRING_BASE if I'm not wrong, so that's even more of a
> > reason to implement suspend call.
>
> Oh, no, just the vring in question.  Not the whole device.
>
> In addition, we still need the GET_VRING_BASE call anyway, because,
> well, we want to restore the vring on the destination via SET_VRING_BASE.
>

Ok, that makes sense, sorry for the confusion!

Thanks!