[Xen-changelog] [xen-3.1-testing] x86_emulate: BT instruction does not write to its 'destination' operand.

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

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1208861729 -3600
# Node ID 563f951a9b1a50a69ae588c9cc16346fcdf543c1
# Parent  1eeab3da5cb6837ea6231b9ad9e76ab9175f0d9a
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 1eeab3da5cb6 -r 563f951a9b1a xen/arch/x86/x86_emulate.c
--- a/xen/arch/x86/x86_emulate.c        Mon Apr 21 20:18:53 2008 +0100
+++ b/xen/arch/x86/x86_emulate.c        Tue Apr 22 11:55:29 2008 +0100
@@ -2154,6 +2154,7 @@ x86_emulate(
 
     case 0xa3: bt: /* bt */
         emulate_2op_SrcV_nobyte("bt", src, dst, _regs.eflags);
+        dst.type = OP_NONE;
         break;
 
     case 0xb3: btr: /* btr */

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