[PATCH 4.9 01/31] kvm: mmu: Dont read PDPTEs when paging is not enabled

Greg Kroah-Hartman
2019-11-15T06:21:59Z

From: Junaid Shahid <junaids@google.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@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/kvm/x86.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -587,7 +587,7 @@ static bool pdptrs_changed(struct kvm_vc
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,
@@ -7491,7 +7491,7 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct
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;
}