Introduce function write_register_operand() to write back the
register operand.
Signed-off-by: Wei Yongjun <yjwei@xxxxxxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 53 +++++++++++++++++++----------------------------
1 files changed, 22 insertions(+), 31 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index c476a67..8bf80a9 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1020,6 +1020,26 @@ exception:
return X86EMUL_PROPAGATE_FAULT;
}
+static void write_register_operand(struct operand *op, unsigned long val,
+ unsigned int bytes)
+{
+ /* The 4-byte case *is* correct: in 64-bit mode we zero-extend. */
+ switch (bytes) {
+ case 1:
+ *(u8 *)op->addr.reg = (u8)val;
+ break;
+ case 2:
+ *(u16 *)op->addr.reg = (u16)val;
+ break;
+ case 4:
+ *op->addr.reg = (u32)val;
+ break; /* 64b: zero-extend */
+ case 8:
+ *op->addr.reg = val;
+ break;
+ }
+}
+
static inline int writeback(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops)
{
@@ -1029,23 +1049,7 @@ static inline int writeback(struct x86_emulate_ctxt *ctxt,
switch (c->dst.type) {
case OP_REG:
- /* The 4-byte case *is* correct:
- * in 64-bit mode we zero-extend.
- */
- switch (c->dst.bytes) {
- case 1:
- *(u8 *)c->dst.addr.reg = (u8)c->dst.val;
- break;
- case 2:
- *(u16 *)c->dst.addr.reg = (u16)c->dst.val;
- break;
- case 4:
- *c->dst.addr.reg = (u32)c->dst.val;
- break; /* 64b: zero-ext */
- case 8:
- *c->dst.addr.reg = c->dst.val;
- break;
- }
+ write_register_operand(&c->dst, c->dst.val, c->dst.bytes);
break;
case OP_MEM:
if (c->lock_prefix)
@@ -2971,20 +2975,7 @@ special_insn:
case 0x86 ... 0x87: /* xchg */
xchg:
/* Write back the register source. */
- switch (c->dst.bytes) {
- case 1:
- *(u8 *) c->src.addr.reg = (u8) c->dst.val;
- break;
- case 2:
- *(u16 *) c->src.addr.reg = (u16) c->dst.val;
- break;
- case 4:
- *c->src.addr.reg = (u32) c->dst.val;
- break; /* 64b reg: zero-extend */
- case 8:
- *c->src.addr.reg = c->dst.val;
- break;
- }
+ write_register_operand(&c->src, c->dst.val, c->dst.bytes);
/*
* Write back the memory destination with implicit LOCK
* prefix.
--
1.7.0.4
--
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