[Xen-changelog] [xen-3.1-testing] x86_emulate: Disable writeback if BSF/BSR are passed zero input.

["Xen patchbot-3.1-testing" <patchbot-3.1-testing@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1208861979 -3600
# Node ID 3c42ede8b1870960b49d299e544a58053e836903
# Parent  22a54b9d88692d11aa1a4de82a09c80146cd0c6b
x86_emulate: Disable writeback if BSF/BSR are passed zero input.
Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
xen-unstable changeset:   17496:1cc4df5c7fe8b34de2a3258f1cafec94540d1712
xen-unstable date:        Tue Apr 22 11:44:56 2008 +0100
---
 xen/arch/x86/x86_emulate.c |   12 ++++++++++--
 1 files changed, 10 insertions(+), 2 deletions(-)

diff -r 22a54b9d8869 -r 3c42ede8b187 xen/arch/x86/x86_emulate.c
--- a/xen/arch/x86/x86_emulate.c        Tue Apr 22 11:58:52 2008 +0100
+++ b/xen/arch/x86/x86_emulate.c        Tue Apr 22 11:59:39 2008 +0100
@@ -2206,7 +2206,11 @@ x86_emulate(
               : "=r" (dst.val), "=q" (zf)
               : "r" (src.val), "1" (0) );
         _regs.eflags &= ~EFLG_ZF;
-        _regs.eflags |= zf ? EFLG_ZF : 0;
+        if ( zf )
+        {
+            _regs.eflags |= EFLG_ZF;
+            dst.type = OP_NONE;
+        }
         break;
     }
 
@@ -2216,7 +2220,11 @@ x86_emulate(
               : "=r" (dst.val), "=q" (zf)
               : "r" (src.val), "1" (0) );
         _regs.eflags &= ~EFLG_ZF;
-        _regs.eflags |= zf ? EFLG_ZF : 0;
+        if ( zf )
+        {
+            _regs.eflags |= EFLG_ZF;
+            dst.type = OP_NONE;
+        }
         break;
     }
 

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