linux-kernel - [PATCH 4.4 STABLE] kvm: mmu: Don't read PDPTEs when paging is not enabled

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Message-Id: <20191112001705.5885-1-sean.j.christopherson@intel.com>
Date:   Mon, 11 Nov 2019 16:17:05 -0800
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     stable@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Junaid Shahid <junaids@...gle.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 4.4 STABLE] kvm: mmu: Don't read PDPTEs when paging is not enabled

From: Junaid Shahid <junaids@...gle.com>

Upstream commit d35b34a9a70edae7ef923f100e51b8b5ae9fe899.

kvm should not attempt to read guest PDPTEs when CR0.PG = 0 and
CR4.PAE = 1.

Signed-off-by: Junaid Shahid <junaids@...gle.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 arch/x86/kvm/x86.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2b47fd3d4b8c..ad8e19fee71e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -575,7 +575,7 @@ static bool pdptrs_changed(struct kvm_vcpu *vcpu)
 	gfn_t gfn;
 	int r;
 
-	if (is_long_mode(vcpu) || !is_pae(vcpu))
+	if (is_long_mode(vcpu) || !is_pae(vcpu) || !is_paging(vcpu))
 		return false;
 
 	if (!test_bit(VCPU_EXREG_PDPTR,
@@ -7168,7 +7168,7 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
 		kvm_update_cpuid(vcpu);
 
 	idx = srcu_read_lock(&vcpu->kvm->srcu);
-	if (!is_long_mode(vcpu) && is_pae(vcpu)) {
+	if (!is_long_mode(vcpu) && is_pae(vcpu) && is_paging(vcpu)) {
 		load_pdptrs(vcpu, vcpu->arch.walk_mmu, kvm_read_cr3(vcpu));
 		mmu_reset_needed = 1;
 	}
-- 
2.24.0