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From: Marcelo Tosatti <mtosatti@redhat.com>
To: Gleb Natapov <gleb@redhat.com>, Avi Kivity <avi.kivity@gmail.com>
Cc: kvm <kvm@vger.kernel.org>
Subject: KVM: VMX: fix incorrect cached cpl value with real/v8086 modes
Date: Wed, 19 Dec 2012 11:29:26 -0200	[thread overview]
Message-ID: <20121219132926.GA3551@amt.cnet> (raw)



CPL is always 0 when in real mode, and always 3 when virtual 8086 mode.

Using values other than those can cause failures on operations that check CPL.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index a4ecf7c..3abe433 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3215,13 +3215,6 @@ static u64 vmx_get_segment_base(struct kvm_vcpu *vcpu, int seg)
 
 static int __vmx_get_cpl(struct kvm_vcpu *vcpu)
 {
-	if (!is_protmode(vcpu))
-		return 0;
-
-	if (!is_long_mode(vcpu)
-	    && (kvm_get_rflags(vcpu) & X86_EFLAGS_VM)) /* if virtual 8086 */
-		return 3;
-
 	return vmx_read_guest_seg_selector(to_vmx(vcpu), VCPU_SREG_CS) & 3;
 }
 
@@ -3229,6 +3222,13 @@ static int vmx_get_cpl(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 
+	if (!is_protmode(vcpu))
+		return 0;
+
+	if (!is_long_mode(vcpu)
+	    && (kvm_get_rflags(vcpu) & X86_EFLAGS_VM)) /* if virtual 8086 */
+		return 3;
+
 	/*
 	 * If we enter real mode with cs.sel & 3 != 0, the normal CPL calculations
 	 * fail; use the cache instead.

             reply	other threads:[~2012-12-19 13:29 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-19 13:29 Marcelo Tosatti [this message]
     [not found] ` <CAEbWair0awmpB9QXFGXJmooSsHg3B6P3uZrmLcyzs=T70TS7VA@mail.gmail.com>
2012-12-25 12:48   ` KVM: VMX: fix incorrect cached cpl value with real/v8086 modes Gleb Natapov
2012-12-25 21:37     ` Marcelo Tosatti
2012-12-26  5:25       ` Gleb Natapov
2012-12-26 13:25         ` Marcelo Tosatti
2012-12-26 13:33           ` Gleb Natapov
2013-01-01 23:36             ` Marcelo Tosatti
2013-01-03  8:11               ` Gleb Natapov
2013-01-03 13:19                 ` Marcelo Tosatti
2013-01-04 11:16                   ` Gleb Natapov
2013-01-01 23:41   ` Marcelo Tosatti
2013-01-03 13:49 ` KVM: VMX: fix incorrect cached cpl value with real/v8086 modes (v2) Marcelo Tosatti
2013-01-07 21:27   ` KVM: VMX: fix incorrect cached cpl value with real/v8086 modes (v3) Marcelo Tosatti
2013-01-08 10:56     ` Gleb Natapov

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