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authorGleb Natapov <gleb@redhat.com>2013-11-04 15:52:41 +0200
committerGleb Natapov <gleb@redhat.com>2013-11-05 09:11:18 +0200
commitaa9ac1a6323d21065e121902fef4f1b6c07c37c7 (patch)
tree8d2691f0b1633519595db3b3244b3a84a1bae46a /arch/x86/kvm/emulate.c
parent95f328d3ad1a8e4e3175a18546fb35c495e31130 (diff)
KVM: emulator: check rex prefix inside decode_register()
All decode_register() callers check if instruction has rex prefix to properly decode one byte operand. It make sense to move the check inside. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Gleb Natapov <gleb@redhat.com>
Diffstat (limited to 'arch/x86/kvm/emulate.c')
-rw-r--r--arch/x86/kvm/emulate.c18
1 files changed, 7 insertions, 11 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 282d28cb9931..0bd372f3c989 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -785,9 +785,10 @@ static int do_insn_fetch(struct x86_emulate_ctxt *ctxt,
* @highbyte_regs specifies whether to decode AH,CH,DH,BH.
*/
static void *decode_register(struct x86_emulate_ctxt *ctxt, u8 modrm_reg,
- int highbyte_regs)
+ int byteop)
{
void *p;
+ int highbyte_regs = (ctxt->rex_prefix == 0) && byteop;
if (highbyte_regs && modrm_reg >= 4 && modrm_reg < 8)
p = (unsigned char *)reg_rmw(ctxt, modrm_reg & 3) + 1;
@@ -1024,7 +1025,6 @@ static void decode_register_operand(struct x86_emulate_ctxt *ctxt,
struct operand *op)
{
unsigned reg = ctxt->modrm_reg;
- int highbyte_regs = ctxt->rex_prefix == 0;
if (!(ctxt->d & ModRM))
reg = (ctxt->b & 7) | ((ctxt->rex_prefix & 1) << 3);
@@ -1046,10 +1046,10 @@ static void decode_register_operand(struct x86_emulate_ctxt *ctxt,
op->type = OP_REG;
if (ctxt->d & ByteOp) {
- op->addr.reg = decode_register(ctxt, reg, highbyte_regs);
+ op->addr.reg = decode_register(ctxt, reg, true);
op->bytes = 1;
} else {
- op->addr.reg = decode_register(ctxt, reg, 0);
+ op->addr.reg = decode_register(ctxt, reg, false);
op->bytes = ctxt->op_bytes;
}
fetch_register_operand(op);
@@ -1082,12 +1082,10 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
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,
- highbyte_regs && (ctxt->d & ByteOp));
+ ctxt->d & ByteOp);
if (ctxt->d & Sse) {
op->type = OP_XMM;
op->bytes = 16;
@@ -4117,10 +4115,8 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op,
case OpMem8:
ctxt->memop.bytes = 1;
if (ctxt->memop.type == OP_REG) {
- int highbyte_regs = ctxt->rex_prefix == 0;
-
- ctxt->memop.addr.reg = decode_register(ctxt, ctxt->modrm_rm,
- highbyte_regs);
+ ctxt->memop.addr.reg = decode_register(ctxt,
+ ctxt->modrm_rm, true);
fetch_register_operand(&ctxt->memop);
}
goto mem_common;

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