File 53a3effd-VT-d-qinval-make-local-variable-volatile.patch of Package xen.openSUSE_13.1_Update

# Commit ceec46c02074e1b2ade0b13c3c4a2f3942ae698c
# Date 2014-06-20 10:25:33 +0200
# Author Jan Beulich <jbeulich@suse.com>
# Committer Jan Beulich <jbeulich@suse.com>
VT-d/qinval: make local variable used for communication with IOMMU "volatile"

Without that there is - afaict - nothing preventing the compiler from
putting the variable into a register for the duration of the wait loop.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Yang Zhang <yang.z.zhang@intel.com>

--- a/xen/drivers/passthrough/vtd/qinval.c
+++ b/xen/drivers/passthrough/vtd/qinval.c
@@ -196,7 +196,7 @@ static int queue_invalidate_wait(struct 
     u8 iflag, u8 sw, u8 fn)
 {
     s_time_t start_time;
-    u32 poll_slot = QINVAL_STAT_INIT;
+    volatile u32 poll_slot = QINVAL_STAT_INIT;
     int index = -1;
     int ret = -1;
     unsigned long flags;