WARN and skip the emulated MMIO fastpath if a private, reserved page fault is encountered, as private+reserved should be an impossible combination (KVM should never create an MMIO SPTE for a private access). Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> --- arch/x86/kvm/mmu/mmu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index bd342ebd0809..9206cfa58feb 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -5866,7 +5866,8 @@ int noinline kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 err error_code |= PFERR_PRIVATE_ACCESS; r = RET_PF_INVALID; - if (unlikely(error_code & PFERR_RSVD_MASK)) { + if (unlikely((error_code & PFERR_RSVD_MASK) && + !WARN_ON_ONCE(error_code & PFERR_PRIVATE_ACCESS))) { r = handle_mmio_page_fault(vcpu, cr2_or_gpa, direct); if (r == RET_PF_EMULATE) goto emulate; -- 2.44.0.278.ge034bb2e1d-goog