diff options
| -rw-r--r-- | arch/x86/kvm/mmu/mmu.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index b3be690d081a..444e068e6ad9 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4221,7 +4221,15 @@ static inline u64 reserved_hpa_bits(void) void reset_shadow_zero_bits_mask(struct kvm_vcpu *vcpu, struct kvm_mmu *context) { - bool uses_nx = context->nx || + /* + * KVM uses NX when TDP is disabled to handle a variety of scenarios, + * notably for huge SPTEs if iTLB multi-hit mitigation is enabled and + * to generate correct permissions for CR0.WP=0/CR4.SMEP=1/EFER.NX=0. + * The iTLB multi-hit workaround can be toggled at any time, so assume + * NX can be used by any non-nested shadow MMU to avoid having to reset + * MMU contexts. Note, KVM forces EFER.NX=1 when TDP is disabled. + */ + bool uses_nx = context->nx || !tdp_enabled || context->mmu_role.base.smep_andnot_wp; struct rsvd_bits_validate *shadow_zero_check; int i; |