[PATCH 4.14 001/239] kvm: mmu: Dont read PDPTEs when paging is not enabled

From: Greg Kroah-Hartman
Date: Tue Nov 19 2019 - 00:43:51 EST


From: Junaid Shahid <junaids@xxxxxxxxxx>

[ 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@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 dcee3282112dc..dc1b6d5bb16d6 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -620,7 +620,7 @@ 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,
@@ -7787,7 +7787,7 @@ 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;
}
--
2.20.1