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authorTakuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>2011-04-13 00:24:55 +0900
committerAvi Kivity <avi@redhat.com>2011-05-11 07:57:08 -0400
commit575e7c1417d41dd72ddf2a49965f833ce9352e92 (patch)
tree0f7d85332966e89520dd00fcee03e66b47fdb15e /arch/x86/kvm
parentbe6d05cfdf1f2ddbdc367a6433d8eac49d6bfe6f (diff)
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KVM: x86 emulator: Disable writeback for CMP emulation
This stops "CMP r/m, reg" to write back the data into memory. Pointed out by Avi. The writeback suppression now covers CMP, CMPS, SCAS. Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r--arch/x86/kvm/emulate.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 2ec69bc..1e0e3f8 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3671,6 +3671,7 @@ special_insn:
break;
case 0x38 ... 0x3d:
cmp: /* cmp */
+ c->dst.type = OP_NONE; /* Disable writeback. */
emulate_2op_SrcV("cmp", c->src, c->dst, ctxt->eflags);
break;
case 0x40 ... 0x47: /* inc r16/r32 */
@@ -3797,7 +3798,6 @@ special_insn:
rc = emulate_popf(ctxt, ops, &c->dst.val, c->op_bytes);
break;
case 0xa6 ... 0xa7: /* cmps */
- c->dst.type = OP_NONE; /* Disable writeback. */
goto cmp;
case 0xa8 ... 0xa9: /* test ax, imm */
goto test;