| Message ID | 20230927140016.2317404-2-i.maximets@ovn.org |
|---|---|
| State | New |
| Headers | show |
| Series | virtio: clean up of virtqueue_split_read_next_desc() | expand |
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 4577f3f5b3..37584aaa74 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -1050,8 +1050,6 @@ static int virtqueue_split_read_next_desc(VirtIODevice *vdev, VRingDesc *desc, /* Check they're not leading us off end of descriptors. */ *next = desc->next; - /* Make sure compiler knows to grab that: we don't want it changing! */ - smp_wmb(); if (*next >= max) { virtio_error(vdev, "Desc next is %u", *next);
It was supposed to be a compiler barrier and it was a compiler barrier initially called 'wmb' when virtio core support was introduced. Later all the instances of 'wmb' were switched to smp_wmb to fix memory ordering issues on non-x86 platforms. However, this one doesn't need to be an actual barrier, as its only purpose was to ensure that the value is not read twice. And since commit aa570d6fb6bd ("virtio: combine the read of a descriptor") there is no need for a barrier at all, since we're no longer reading guest memory here, but accessing a local structure. Signed-off-by: Ilya Maximets <i.maximets@ovn.org> --- hw/virtio/virtio.c | 2 -- 1 file changed, 2 deletions(-)