[ 092/127] KVM: fix sil/dil/bpl/spl in the mod/rm fields

From: Greg Kroah-Hartman
Date: Wed Jun 05 2013 - 17:46:59 EST


3.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Paolo Bonzini <pbonzini@xxxxxxxxxx>

commit 8acb42070ec4c87a9baab5c7bac626030d5bef28 upstream.

The x86-64 extended low-byte registers were fetched correctly from reg,
but not from mod/rm.

This fixes another bug in the boot of RHEL5.9 64-bit, but it is still
not enough.

Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Gleb Natapov <gleb@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/x86/kvm/emulate.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1239,9 +1239,12 @@ static int decode_modrm(struct x86_emula
ctxt->modrm_seg = VCPU_SREG_DS;

if (ctxt->modrm_mod == 3) {
+ int highbyte_regs = ctxt->rex_prefix == 0;
+
op->type = OP_REG;
op->bytes = (ctxt->d & ByteOp) ? 1 : ctxt->op_bytes;
- op->addr.reg = decode_register(ctxt, ctxt->modrm_rm, ctxt->d & ByteOp);
+ op->addr.reg = decode_register(ctxt, ctxt->modrm_rm,
+ highbyte_regs && (ctxt->d & ByteOp));
if (ctxt->d & Sse) {
op->type = OP_XMM;
op->bytes = 16;


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