linux-kernel - [PATCH 9/9] KVM: x86: smsw emulation is incorrect in 64-bit mode

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Date:	Mon,  2 Jun 2014 18:34:11 +0300
From:	Nadav Amit <namit@...technion.ac.il>
To:	pbonzini@...hat.com
Cc:	gleb@...nel.org, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com, x86@...nel.org, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org, Nadav Amit <namit@...technion.ac.il>
Subject: [PATCH 9/9] KVM: x86: smsw emulation is incorrect in 64-bit mode

In 64-bit mode, when the destination is a register, the assignment is done
according to the operand size. Otherwise (memory operand or no 64-bit mode), a
16-bit assignment is performed.

Currently, 16-bit assignment is always done to the destination.

Signed-off-by: Nadav Amit <namit@...technion.ac.il>
---
 arch/x86/kvm/emulate.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index a151f8d..9b5d97d 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3235,7 +3235,8 @@ static int em_lidt(struct x86_emulate_ctxt *ctxt)
 
 static int em_smsw(struct x86_emulate_ctxt *ctxt)
 {
-	ctxt->dst.bytes = 2;
+	if (ctxt->dst.type == OP_MEM)
+		ctxt->dst.bytes = 2;
 	ctxt->dst.val = ctxt->ops->get_cr(ctxt, 0);
 	return X86EMUL_CONTINUE;
 }
-- 
1.9.1

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