Re: [RFC PATCH v4 17/20] vhost: Use VRING_AVAIL_F_NO_INTERRUPT at device call on shadow virtqueue

[Eugenio Perez Martin]

On Wed, Oct 13, 2021 at 6:36 AM Jason Wang <jasowang@redhat.com> wrote:
>
>
> 在 2021/10/1 下午3:06, Eugenio Pérez 写道:
> > Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
>
>
> Commit log please.
>
> Thanks
>

Sorry, this was another commit that was intended to be squashed.

I think I squashed two other (previous) commits by mistake in the
rebase editor, that's why you detected unrelated changes and mixed SVQ
& vhost-vdpa changes. I will take more care for the next series I
send.

Thanks!

>
> > ---
> >   hw/virtio/vhost-shadow-virtqueue.c | 24 +++++++++++++++++++++++-
> >   1 file changed, 23 insertions(+), 1 deletion(-)
> >
> > diff --git a/hw/virtio/vhost-shadow-virtqueue.c 
> > b/hw/virtio/vhost-shadow-virtqueue.c
> > index 775f8d36a0..2fd0bab75d 100644
> > --- a/hw/virtio/vhost-shadow-virtqueue.c
> > +++ b/hw/virtio/vhost-shadow-virtqueue.c
> > @@ -60,6 +60,9 @@ typedef struct VhostShadowVirtqueue {
> >
> >       /* Next head to consume from device */
> >       uint16_t used_idx;
> > +
> > +    /* Cache for the exposed notification flag */
> > +    bool notification;
> >   } VhostShadowVirtqueue;
> >
> >   /* If the device is using some of these, SVQ cannot communicate */
> > @@ -105,6 +108,24 @@ bool vhost_svq_valid_device_features(uint64_t 
> > *dev_features)
> >       return r;
> >   }
> >
> > +static void vhost_svq_set_notification(VhostShadowVirtqueue *svq, bool 
> > enable)
> > +{
> > +    uint16_t notification_flag;
> > +
> > +    if (svq->notification == enable) {
> > +        return;
> > +    }
> > +
> > +    notification_flag = cpu_to_le16(VRING_AVAIL_F_NO_INTERRUPT);
> > +
> > +    svq->notification = enable;
> > +    if (enable) {
> > +        svq->vring.avail->flags &= ~notification_flag;
> > +    } else {
> > +        svq->vring.avail->flags |= notification_flag;
> > +    }
> > +}
> > +
> >   static void vhost_vring_write_descs(VhostShadowVirtqueue *svq,
> >                                       const struct iovec *iovec,
> >                                       size_t num, bool more_descs, bool 
> > write)
> > @@ -273,7 +294,7 @@ static void vhost_svq_handle_call_no_test(EventNotifier 
> > *n)
> >       do {
> >           unsigned i = 0;
> >
> > -        /* TODO: Use VRING_AVAIL_F_NO_INTERRUPT */
> > +        vhost_svq_set_notification(svq, false);
> >           while (true) {
> >               g_autofree VirtQueueElement *elem = vhost_svq_get_buf(svq);
> >               if (!elem) {
> > @@ -286,6 +307,7 @@ static void vhost_svq_handle_call_no_test(EventNotifier 
> > *n)
> >
> >           virtqueue_flush(vq, i);
> >           event_notifier_set(&svq->guest_call_notifier);
> > +        vhost_svq_set_notification(svq, true);
> >       } while (vhost_svq_more_used(svq));
> >   }
> >
>