drivers/xen/xenbus/xenbus_comms.c 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@xxxxxxxxxx>
Acked-by: David Vrabel <david.vrabel@xxxxxxxxxx>
---
drivers/xen/xenbus/xenbus_comms.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/xen/xenbus/xenbus_comms.c b/drivers/xen/xenbus/xenbus_comms.c
index fdb0f33..ecdecce 100644
--- a/drivers/xen/xenbus/xenbus_comms.c
+++ b/drivers/xen/xenbus/xenbus_comms.c
@@ -123,14 +123,14 @@ int xb_write(const void *data, unsigned len)
avail = len;
/* Must write data /after/ reading the consumer index. */
- mb();
+ virt_mb();
memcpy(dst, data, avail);
data += avail;
len -= avail;
/* Other side must not see new producer until data is there. */
- wmb();
+ virt_wmb();
intf->req_prod += avail;
/* Implies mb(): other side will see the updated producer. */
@@ -180,14 +180,14 @@ int xb_read(void *data, unsigned len)
avail = len;
/* Must read data /after/ reading the producer index. */
- rmb();
+ virt_rmb();
memcpy(data, src, avail);
data += avail;
len -= avail;
/* Other side must not see free space until we've copied out */
- mb();
+ virt_mb();
intf->rsp_cons += avail;
pr_debug("Finished read of %i bytes (%i to go)\n", avail, len);
--
MST
