Re: [RFC PATCH v9 03/23] vdpa: delay set_vring_ready after DRIVER_OK

[Eugenio Perez Martin]

On Fri, Jul 8, 2022 at 11:06 AM Jason Wang <jasowang@redhat.com> wrote:
>
> On Thu, Jul 7, 2022 at 2:40 AM Eugenio Pérez <eperezma@redhat.com> wrote:
> >
> > To restore the device in the destination of a live migration we send the
> > commands through control virtqueue. For a device to read CVQ it must
> > have received DRIVER_OK status bit.
> >
> > However this open a window where the device could start receiving
> > packets in rx queue 0 before it receive the RSS configuration. To avoid
> > that, we will not send vring_enable until all configuration is used by
> > the device.
> >
> > As a first step, reverse the DRIVER_OK and SET_VRING_ENABLE steps.
>
> I wonder if it's better to delay this to the series that implements
> migration since the shadow cvq doesn't depends on this?
>

(Forgot to add) this series is already capable of doing migration with
CVQ. It's just that it must use SVQ from the moment the source VM
boots up, which is far from ideal.

Thanks!