| Message ID | 1478704922-3400-3-git-send-email-yuri.benditovich@daynix.com |
|---|---|
| State | New |
| Headers | show |
On 09/11/2016 16:22, yuri.benditovich@daynix.com wrote: > From: Yuri Benditovich <yuri.benditovich@daynix.com> > > Make virtio queue suitable for push operation from qemu > after vhost was stopped. > > Signed-off-by: Yuri Benditovich <yuri.benditovich@daynix.com> > --- > hw/virtio/vhost.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c > index bd051ab..2e990d0 100644 > --- a/hw/virtio/vhost.c > +++ b/hw/virtio/vhost.c > @@ -963,6 +963,7 @@ static void vhost_virtqueue_stop(struct vhost_dev *dev, > virtio_queue_set_last_avail_idx(vdev, idx, state.num); > } > virtio_queue_invalidate_signalled_used(vdev, idx); > + virtio_queue_update_used_idx(vdev, idx); All three functions virtio_queue_set_last_avail_idx, virtio_queue_invalidate_signalled_used, virtio_queue_update_used_idx are only used here. Plus, virtio_queue_set_last_avail_idx is always called in practice, since the only failure modes for VHOST_GET_VRING_BASE are EFAULT and out-of-range virtqueue number. In both cases QEMU can ignore the other two steps. So perhaps we should have a single function virtio_queue_set_vring_base, taking a vhost_vring_state struct? It can do all three. Paolo > > /* In the cross-endian case, we need to reset the vring endianness to > * native as legacy devices expect so by default. >
On Wed, Nov 09, 2016 at 06:07:29PM +0100, Paolo Bonzini wrote: > > > On 09/11/2016 16:22, yuri.benditovich@daynix.com wrote: > > From: Yuri Benditovich <yuri.benditovich@daynix.com> > > > > Make virtio queue suitable for push operation from qemu > > after vhost was stopped. > > > > Signed-off-by: Yuri Benditovich <yuri.benditovich@daynix.com> > > --- > > hw/virtio/vhost.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c > > index bd051ab..2e990d0 100644 > > --- a/hw/virtio/vhost.c > > +++ b/hw/virtio/vhost.c > > @@ -963,6 +963,7 @@ static void vhost_virtqueue_stop(struct vhost_dev *dev, > > virtio_queue_set_last_avail_idx(vdev, idx, state.num); > > } > > virtio_queue_invalidate_signalled_used(vdev, idx); > > + virtio_queue_update_used_idx(vdev, idx); > > All three functions virtio_queue_set_last_avail_idx, > virtio_queue_invalidate_signalled_used, virtio_queue_update_used_idx are > only used here. > > Plus, virtio_queue_set_last_avail_idx is always called in practice, > since the only failure modes for VHOST_GET_VRING_BASE are EFAULT and > out-of-range virtqueue number. In both cases QEMU can ignore the other > two steps. > > So perhaps we should have a single function virtio_queue_set_vring_base, > taking a vhost_vring_state struct? It can do all three. > > Paolo I don't object but I think the bugfix is helpful in this QEMU version, and this change is minimally intrusive. > > > > /* In the cross-endian case, we need to reset the vring endianness to > > * native as legacy devices expect so by default. > >
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c index bd051ab..2e990d0 100644 --- a/hw/virtio/vhost.c +++ b/hw/virtio/vhost.c @@ -963,6 +963,7 @@ static void vhost_virtqueue_stop(struct vhost_dev *dev, virtio_queue_set_last_avail_idx(vdev, idx, state.num); } virtio_queue_invalidate_signalled_used(vdev, idx); + virtio_queue_update_used_idx(vdev, idx); /* In the cross-endian case, we need to reset the vring endianness to * native as legacy devices expect so by default.