On Tue, Jul 10, 2018 at 01:50:03PM +0800, Jason Wang wrote: > On 2018年07月09日 15:22, Tiwei Bie wrote: > > @@ -1059,9 +1059,19 @@ static bool virtqueue_kick_prepare_packed(struct virtqueue *_vq) > > * suppressions. */ > > virtio_mb(vq->weak_barriers); > > + old = vq->next_avail_idx - vq->num_added; > > + new = vq->next_avail_idx; > > + vq->num_added = 0; > > + > > snapshot = *(u32 *)vq->vring_packed.device; > > I think we should use READ_ONCE() to prevent compiler from re-reading. I'll do it. Thanks! Best regards, Tiwei Bie > > > + off_wrap = virtio16_to_cpu(_vq->vdev, (__virtio16)(snapshot & 0xffff)); > > flags = virtio16_to_cpu(_vq->vdev, (__virtio16)(snapshot >> 16)) & 0x3; > > + wrap_counter = off_wrap >> 15; > > + event_idx = off_wrap & ~(1 << 15); > > + if (wrap_counter != vq->avail_wrap_counter) > > + event_idx -= vq->vring_packed.num; > > Thanks > _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
