[Xen-changelog] [xen-3.2-testing] x86_emulate: BT instruction does not write to its 'destination' operand.

["Xen patchbot-3.2-testing" <patchbot-3.2-testing@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1208861396 -3600
# Node ID cf80cf2709b6b036c73f009a52504572c8fc8ec7
# Parent  cae7dab0b0f94890c47702a254889b7d3b415e08
x86_emulate: BT instruction does not write to its 'destination' operand.

This fixes w2k3 guests occasionally writing back to read-only registers.

Signed-off-by: Xu Dongxiao <dongxiao.xu@xxxxxxxxx>
xen-unstable changeset:   17492:d9a74b8e9b1a345cc3d82efb837014e5658522c2
xen-unstable date:        Tue Apr 22 10:27:04 2008 +0100
---
 xen/arch/x86/x86_emulate.c |    1 +
 1 files changed, 1 insertion(+)

diff -r cae7dab0b0f9 -r cf80cf2709b6 xen/arch/x86/x86_emulate.c
--- a/xen/arch/x86/x86_emulate.c        Mon Apr 21 20:16:48 2008 +0100
+++ b/xen/arch/x86/x86_emulate.c        Tue Apr 22 11:49:56 2008 +0100
@@ -2968,6 +2968,7 @@ x86_emulate(
 
     case 0xa3: bt: /* bt */
         emulate_2op_SrcV_nobyte("bt", src, dst, _regs.eflags);
+        dst.type = OP_NONE;
         break;
 
     case 0xa4: /* shld imm8,r,r/m */

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