From: Paolo Bonzini pbonzini@redhat.com
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@vger.kernel.org Reviewed-by: Sean Christopherson seanjc@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 @@ -49,6 +49,7 @@ X86_CR4_LA57)
#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 @@ -1605,8 +1605,7 @@ 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;