[Xen-changelog] [xen-unstable] x86_emulate: INS/OUTS need Mov attribute to force writeback (since

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

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1204544860 0
# Node ID c89f6ed5635179695c92810a9c9eec205e5d0d78
# Parent  a142ddb40b1c77d6b8726a2b57ac324ab74c6d06
x86_emulate: INS/OUTS need Mov attribute to force writeback (since
dst.orig_val is not initialised). Also, Mov attribute on cmpxchg is
not necessary -- when destination is memory (i.e., successful cmpxchg)
then dst.orig_val is already correctly filled in. In case that
dst.orig_val == dst.val then the instruction linearises at the point
we first read the destination (and initialised dst.orig_val).
Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
---
 xen/arch/x86/x86_emulate.c |    4 +---
 1 files changed, 1 insertion(+), 3 deletions(-)

diff -r a142ddb40b1c -r c89f6ed56351 xen/arch/x86/x86_emulate.c
--- a/xen/arch/x86/x86_emulate.c        Mon Mar 03 11:09:33 2008 +0000
+++ b/xen/arch/x86/x86_emulate.c        Mon Mar 03 11:47:40 2008 +0000
@@ -106,7 +106,7 @@ static uint8_t opcode_table[256] = {
     /* 0x68 - 0x6F */
     ImplicitOps|Mov, DstReg|SrcImm|ModRM|Mov,
     ImplicitOps|Mov, DstReg|SrcImmByte|ModRM|Mov,
-    ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
+    ImplicitOps|Mov, ImplicitOps|Mov, ImplicitOps|Mov, ImplicitOps|Mov,
     /* 0x70 - 0x77 */
     ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
     ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
@@ -2862,8 +2862,6 @@ x86_emulate(
         src.orig_val = src.val;
         src.val = _regs.eax;
         emulate_2op_SrcV("cmp", src, dst, _regs.eflags);
-        /* Always write back. The question is: where to? */
-        d |= Mov;
         if ( _regs.eflags & EFLG_ZF )
         {
             /* Success: write back to memory. */

_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-changelog