xen/io: use virt_xxx barriers
authorMichael S. Tsirkin <mst@redhat.com>
Sun, 27 Dec 2015 16:02:16 +0000 (18:02 +0200)
committerMichael S. Tsirkin <mst@redhat.com>
Tue, 12 Jan 2016 18:47:03 +0000 (20:47 +0200)
commit506b02eb1cf79838b76c6e3e43171cf960f01fc8
tree4e89ac8ba0cfe3752e005aaf49f9706176d92fe8
parent5bb0c9be2ac9a98513d43969e2b5c3d02cb271c8
xen/io: use virt_xxx barriers

include/xen/interface/io/ring.h uses
full memory barriers to communicate with the other side.

For guests compiled with CONFIG_SMP, smp_wmb and smp_mb
would be sufficient, so mb() and wmb() here are only needed if
a non-SMP guest runs on an SMP host.

Switch to virt_xxx barriers which serve this exact purpose.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
include/xen/interface/io/ring.h