Re: [PATCH v2 11/14] vdpa: Adapt vhost_vdpa_get_vring_base to SVQ

[Eugenio Perez Martin]

On Mon, Feb 28, 2022 at 8:38 AM Jason Wang <jasowang@redhat.com> wrote:
>
>
> 在 2022/2/27 下午9:41, Eugenio Pérez 写道:
> > This is needed to achieve migration, so the destination can restore its
> > index.
>
>
> I suggest to duplicate the comment below here.
>

Sure, I'll duplicate here in the commit message.

Thanks!

> Thanks
>
>
> > Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> > ---
> >   hw/virtio/vhost-vdpa.c | 17 +++++++++++++++++
> >   1 file changed, 17 insertions(+)
> >
> > diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> > index 56f9f125cd..accc4024c2 100644
> > --- a/hw/virtio/vhost-vdpa.c
> > +++ b/hw/virtio/vhost-vdpa.c
> > @@ -1180,8 +1180,25 @@ static int vhost_vdpa_set_vring_base(struct 
> > vhost_dev *dev,
> >   static int vhost_vdpa_get_vring_base(struct vhost_dev *dev,
> >                                          struct vhost_vring_state *ring)
> >   {
> > +    struct vhost_vdpa *v = dev->opaque;
> >       int ret;
> >
> > +    if (v->shadow_vqs_enabled) {
> > +        VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs,
> > +                                                      ring->index);
> > +
> > +        /*
> > +         * Setting base as last used idx, so destination will see as 
> > available
> > +         * all the entries that the device did not use, including the 
> > in-flight
> > +         * processing ones.
> > +         *
> > +         * TODO: This is ok for networking, but other kinds of devices 
> > might
> > +         * have problems with these retransmissions.
> > +         */
> > +        ring->num = svq->last_used_idx;
> > +        return 0;
> > +    }
> > +
> >       ret = vhost_vdpa_call(dev, VHOST_GET_VRING_BASE, ring);
> >       trace_vhost_vdpa_get_vring_base(dev, ring->index, ring->num);
> >       return ret;
>