KVM: x86 emulator: Extract the common code of SrcReg and DstReg
Share the common parts of SrcReg and DstReg decoding.
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c
index 087a820..58ceb66 100644
--- a/drivers/kvm/x86_emulate.c
+++ b/drivers/kvm/x86_emulate.c
@@ -520,6 +520,34 @@
return (!!rc ^ (condition & 1));
}
+static void decode_register_operand(struct operand *op,
+ struct decode_cache *c,
+ int highbyte_regs,
+ int inhibit_bytereg)
+{
+ op->type = OP_REG;
+ if ((c->d & ByteOp) && !inhibit_bytereg) {
+ op->ptr = decode_register(c->modrm_reg, c->regs, highbyte_regs);
+ op->val = *(u8 *)op->ptr;
+ op->bytes = 1;
+ } else {
+ op->ptr = decode_register(c->modrm_reg, c->regs, 0);
+ op->bytes = c->op_bytes;
+ switch (op->bytes) {
+ case 2:
+ op->val = *(u16 *)op->ptr;
+ break;
+ case 4:
+ op->val = *(u32 *)op->ptr;
+ break;
+ case 8:
+ op->val = *(u64 *) op->ptr;
+ break;
+ }
+ }
+ op->orig_val = op->val;
+}
+
int
x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
{
@@ -809,31 +837,7 @@
case SrcNone:
break;
case SrcReg:
- c->src.type = OP_REG;
- if (c->d & ByteOp) {
- c->src.ptr =
- decode_register(c->modrm_reg, c->regs,
- (rex_prefix == 0));
- c->src.val = c->src.orig_val = *(u8 *)c->src.ptr;
- c->src.bytes = 1;
- } else {
- c->src.ptr =
- decode_register(c->modrm_reg, c->regs, 0);
- switch ((c->src.bytes = c->op_bytes)) {
- case 2:
- c->src.val = c->src.orig_val =
- *(u16 *) c->src.ptr;
- break;
- case 4:
- c->src.val = c->src.orig_val =
- *(u32 *) c->src.ptr;
- break;
- case 8:
- c->src.val = c->src.orig_val =
- *(u64 *) c->src.ptr;
- break;
- }
- }
+ decode_register_operand(&c->src, c, rex_prefix == 0, 0);
break;
case SrcMem16:
c->src.bytes = 2;
@@ -891,30 +895,8 @@
/* Special instructions do their own operand decoding. */
return 0;
case DstReg:
- c->dst.type = OP_REG;
- if ((c->d & ByteOp)
- && !(c->twobyte &&
- (c->b == 0xb6 || c->b == 0xb7))) {
- c->dst.ptr =
- decode_register(c->modrm_reg, c->regs,
- (rex_prefix == 0));
- c->dst.val = *(u8 *) c->dst.ptr;
- c->dst.bytes = 1;
- } else {
- c->dst.ptr =
- decode_register(c->modrm_reg, c->regs, 0);
- switch ((c->dst.bytes = c->op_bytes)) {
- case 2:
- c->dst.val = *(u16 *)c->dst.ptr;
- break;
- case 4:
- c->dst.val = *(u32 *)c->dst.ptr;
- break;
- case 8:
- c->dst.val = *(u64 *)c->dst.ptr;
- break;
- }
- }
+ decode_register_operand(&c->dst, c, rex_prefix == 0,
+ c->twobyte && (c->b == 0xb6 || c->b == 0xb7));
break;
case DstMem:
if ((c->d & ModRM) && c->modrm_mod == 3) {