[PATCH 09/54] KVM: x86 emulator: Make a distinction between repeat prefixes F3 and F2

[Avi Kivity]

From: Guillaume Thouvenin <guillaume.thouvenin@xxxxxxxxxxxx>

cmps and scas instructions accept repeat prefixes F3 and F2. So in
order to emulate those prefixed instructions we need to be able to know
if prefixes are REP/REPE/REPZ or REPNE/REPNZ. Currently kvm doesn't make
this distinction. This patch introduces this distinction.

Signed-off-by: Guillaume Thouvenin <guillaume.thouvenin@xxxxxxxxxxxx>
Signed-off-by: Avi Kivity <avi@xxxxxxxxxxxx>
---
 drivers/kvm/x86_emulate.c |    4 +++-
 drivers/kvm/x86_emulate.h |    4 ++++
 2 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c
index 6e7f774..9f8d59a 100644
--- a/drivers/kvm/x86_emulate.c
+++ b/drivers/kvm/x86_emulate.c
@@ -824,8 +824,10 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 			c->lock_prefix = 1;
 			break;
 		case 0xf2:	/* REPNE/REPNZ */
+			c->rep_prefix = REPNE_PREFIX;
+			break;
 		case 0xf3:	/* REP/REPE/REPZ */
-			c->rep_prefix = 1;
+			c->rep_prefix = REPE_PREFIX;
 			break;
 		default:
 			goto done_prefixes;
diff --git a/drivers/kvm/x86_emulate.h b/drivers/kvm/x86_emulate.h
index 4603b2b..644086e 100644
--- a/drivers/kvm/x86_emulate.h
+++ b/drivers/kvm/x86_emulate.h
@@ -162,6 +162,10 @@ struct x86_emulate_ctxt {
 	struct decode_cache decode;
 };
 
+/* Repeat String Operation Prefix */
+#define REPE_PREFIX  1
+#define REPNE_PREFIX    2
+
 /* Execution mode, passed to the emulator. */
 #define X86EMUL_MODE_REAL     0	/* Real mode.             */
 #define X86EMUL_MODE_PROT16   2	/* 16-bit protected mode. */
-- 
1.5.3.7

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