linux-kernel - [PATCH] KVM: x86: Fix CR3 reserved bits check in long mode

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Date:	Sat, 10 May 2014 09:24:34 +0200
From:	Jan Kiszka <jan.kiszka@....de>
To:	Marcelo Tosatti <mtosatti@...hat.com>, pbonzini@...hat.com
CC:	Nadav Amit <namit@...technion.ac.il>, gleb@...nel.org,
	tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
	x86@...nel.org, kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] KVM: x86: Fix CR3 reserved bits check in long mode

From: Jan Kiszka <jan.kiszka@...mens.com>

Regression of 346874c9: PAE is set in long mode, but that does not mean
we have valid PDPTRs.

Signed-off-by: Jan Kiszka <jan.kiszka@...mens.com>
---
 arch/x86/kvm/x86.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c5582c3..198aac8 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -701,10 +701,11 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
 		return 0;
 	}
 
-	if (is_long_mode(vcpu) && (cr3 & CR3_L_MODE_RESERVED_BITS))
-		return 1;
-	if (is_pae(vcpu) && is_paging(vcpu) &&
-	    !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))
+	if (is_long_mode(vcpu)) {
+		if (cr3 & CR3_L_MODE_RESERVED_BITS)
+			return 1;
+	} else if (is_pae(vcpu) && is_paging(vcpu) &&
+		   !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))
 		return 1;
 
 	vcpu->arch.cr3 = cr3;
-- 
1.8.1.1.298.ge7eed54


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