[PATCH 3/7] KVM: x86 emulator: introduce NoWrite flag

Avi Kivity
2012-12-22T12:35:10Z

Instead of disabling writeback via OP_NONE, just specify NoWrite.

Signed-off-by: Avi Kivity <avi.kivity@gmail.com>
---
arch/x86/kvm/emulate.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 9859df6..9dfbd07 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -150,6 +150,7 @@
#define Unaligned ((u64)1 << 42) /* Explicitly unaligned (e.g. MOVDQU) */
#define Avx ((u64)1 << 43) /* Advanced Vector Extensions */
#define Fastop ((u64)1 << 44) /* Use opcode::u.fastop */
+#define NoWrite ((u64)1 << 45) /* No writeback */

#define X2(x...) x, x
#define X3(x...) X2(x), x
@@ -1584,6 +1585,9 @@ static int writeback(struct x86_emulate_ctxt *ctxt)
{
int rc;

+ if (ctxt->d & NoWrite)
+ return X86EMUL_CONTINUE;
+
switch (ctxt->dst.type) {
case OP_REG:
write_register_operand(&ctxt->dst);
--
1.7.11.7