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

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1208861096 -3600
# Node ID 1cc4df5c7fe8b34de2a3258f1cafec94540d1712
# Parent  fec632d30571c40f05e6638477472500ef9cb2c7
x86_emulate: Disable writeback if BSF/BSR are passed zero input.
Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
---
 xen/arch/x86/x86_emulate/x86_emulate.c |   12 ++++++++++--
 1 files changed, 10 insertions(+), 2 deletions(-)

diff -r fec632d30571 -r 1cc4df5c7fe8 xen/arch/x86/x86_emulate/x86_emulate.c
--- a/xen/arch/x86/x86_emulate/x86_emulate.c    Tue Apr 22 11:43:10 2008 +0100
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c    Tue Apr 22 11:44:56 2008 +0100
@@ -3134,7 +3134,11 @@ 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;
     }
 
@@ -3144,7 +3148,11 @@ 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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