diff options
Diffstat (limited to 'arch/x86/kvm/mmu/mmu.c')
| -rw-r--r-- | arch/x86/kvm/mmu/mmu.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index f9080ee50ffa..5f6225c384e6 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2992,9 +2992,15 @@ static bool handle_abnormal_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fa /* * If MMIO caching is disabled, emulate immediately without * touching the shadow page tables as attempting to install an - * MMIO SPTE will just be an expensive nop. + * MMIO SPTE will just be an expensive nop. Do not cache MMIO + * whose gfn is greater than host.MAXPHYADDR, any guest that + * generates such gfns is running nested and is being tricked + * by L0 userspace (you can observe gfn > L1.MAXPHYADDR if + * and only if L1's MAXPHYADDR is inaccurate with respect to + * the hardware's). */ - if (unlikely(!shadow_mmio_value)) { + if (unlikely(!shadow_mmio_value) || + unlikely(fault->gfn > kvm_mmu_max_gfn())) { *ret_val = RET_PF_EMULATE; return true; } |