From: Paolo Bonzini <pbonzini@xxxxxxxxxx>
commit d6174299365ddbbf491620c0b8c5ca1a6ef2eea5 upstream.
While the guest runs, EFER.LME cannot change unless CR0.PG is clear, and
therefore EFER.NX is the only bit that can affect the MMU role. However,
set_efer accepts a host-initiated change to EFER.LME even with CR0.PG=1.
In that case, the MMU has to be reset.
Fixes: 11988499e62b ("KVM: x86: Skip EFER vs. guest CPUID checks for host-initiated writes")
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/mmu.h | 1 +
arch/x86/kvm/x86.c | 3 +--
2 files changed, 2 insertions(+), 2 deletions(-)
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -48,6 +48,7 @@
X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_PKE)
#define KVM_MMU_CR0_ROLE_BITS (X86_CR0_PG | X86_CR0_WP)
+#define KVM_MMU_EFER_ROLE_BITS (EFER_LME | EFER_NX)
static __always_inline u64 rsvd_bits(int s, int e)
{
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1656,8 +1656,7 @@ static int set_efer(struct kvm_vcpu *vcp
return r;
}
- /* Update reserved bits */
- if ((efer ^ old_efer) & EFER_NX)
+ if ((efer ^ old_efer) & KVM_MMU_EFER_ROLE_BITS)
kvm_mmu_reset_context(vcpu);
return 0;
