From: Rusty Russell <rusty@rustcorp.com.au>
Date: Tue, 2 Jul 2013 06:05:14 +0000 (+0930)
Subject: tools/lguest: real barriers.
X-Git-Tag: firefly_0821_release~176^2~5732^2~6
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=0d69a65e97fc8090ee83c8639137b4b5c8ece237;p=firefly-linux-kernel-4.4.55.git

tools/lguest: real barriers.

Lguest guests are UP, but the host is probably SMP, so real barriers are
required in case the device thread and the guest are on different CPUs.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---

diff --git a/tools/lguest/lguest.c b/tools/lguest/lguest.c
index 49ed25b5bbb9..a64f5cb0c15b 100644
--- a/tools/lguest/lguest.c
+++ b/tools/lguest/lguest.c
@@ -177,8 +177,8 @@ static struct termios orig_term;
  * in precise order.
  */
 #define wmb() __asm__ __volatile__("" : : : "memory")
-#define rmb() __asm__ __volatile__("" : : : "memory")
-#define mb() __asm__ __volatile__("" : : : "memory")
+#define rmb() __asm__ __volatile__("lock; addl $0,0(%%esp)" : : : "memory")
+#define mb() __asm__ __volatile__("lock; addl $0,0(%%esp)" : : : "memory")
 
 /* Wrapper for the last available index.  Makes it easier to change. */
 #define lg_last_avail(vq)	((vq)->last_avail_idx)