linux-kernel - [PATCH 3.12 097/122] KVM: x86: Getting rid of grp45 in emulator

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Date:	Tue, 17 Feb 2015 12:34:44 +0100
From:	Jiri Slaby <jslaby@...e.cz>
To:	stable@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, Nadav Amit <namit@...technion.ac.il>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 3.12 097/122] KVM: x86: Getting rid of grp45 in emulator

From: Nadav Amit <namit@...technion.ac.il>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit f7784046ab7cfc1645f4110b6ed14fbdffc2abee upstream.

Breaking grp45 to the relevant functions to speed up the emulation and simplify
the code. In addition, it is necassary the next patch will distinguish between
far and near branches according to the flags.

Signed-off-by: Nadav Amit <namit@...technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
---
 arch/x86/kvm/emulate.c | 45 ++++++++++++++++++---------------------------
 1 file changed, 18 insertions(+), 27 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index fe10e13070b0..4cb80f2c6fdb 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1998,31 +1998,22 @@ static int em_jmp_far(struct x86_emulate_ctxt *ctxt)
 	return rc;
 }
 
-static int em_grp45(struct x86_emulate_ctxt *ctxt)
+static int em_jmp_abs(struct x86_emulate_ctxt *ctxt)
 {
-	int rc = X86EMUL_CONTINUE;
+	return assign_eip_near(ctxt, ctxt->src.val);
+}
 
-	switch (ctxt->modrm_reg) {
-	case 2: /* call near abs */ {
-		long int old_eip;
-		old_eip = ctxt->_eip;
-		rc = assign_eip_near(ctxt, ctxt->src.val);
-		if (rc != X86EMUL_CONTINUE)
-			break;
-		ctxt->src.val = old_eip;
-		rc = em_push(ctxt);
-		break;
-	}
-	case 4: /* jmp abs */
-		rc = assign_eip_near(ctxt, ctxt->src.val);
-		break;
-	case 5: /* jmp far */
-		rc = em_jmp_far(ctxt);
-		break;
-	case 6:	/* push */
-		rc = em_push(ctxt);
-		break;
-	}
+static int em_call_near_abs(struct x86_emulate_ctxt *ctxt)
+{
+	int rc;
+	long int old_eip;
+
+	old_eip = ctxt->_eip;
+	rc = assign_eip_near(ctxt, ctxt->src.val);
+	if (rc != X86EMUL_CONTINUE)
+		return rc;
+	ctxt->src.val = old_eip;
+	rc = em_push(ctxt);
 	return rc;
 }
 
@@ -3655,11 +3646,11 @@ static const struct opcode group4[] = {
 static const struct opcode group5[] = {
 	F(DstMem | SrcNone | Lock,		em_inc),
 	F(DstMem | SrcNone | Lock,		em_dec),
-	I(SrcMem | Stack,			em_grp45),
+	I(SrcMem | Stack,			em_call_near_abs),
 	I(SrcMemFAddr | ImplicitOps | Stack,	em_call_far),
-	I(SrcMem | Stack,			em_grp45),
-	I(SrcMemFAddr | ImplicitOps,		em_grp45),
-	I(SrcMem | Stack,			em_grp45), D(Undefined),
+	I(SrcMem | Stack,			em_jmp_abs),
+	I(SrcMemFAddr | ImplicitOps,		em_jmp_far),
+	I(SrcMem | Stack,			em_push), D(Undefined),
 };
 
 static const struct opcode group6[] = {
-- 
2.2.2

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