According to AMD, the hypervisor may not be able to determine whether a fault was a GMET fault or an NX fault based on EXITINFO1, and software "must read the relevant VMCB to determine whether a fault was a GMET fault or an NX fault". The APM further details that they meant the CPL field. KVM uses the page fault error code to distinguish the causes of a nested page fault, so recalculate the PFERR_USER_MASK bit of the vmexit information. Only do it for fetches and only if GMET is in use, because KVM does not differentiate based on PFERR_USER_MASK for other nested NPT page faults. Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/svm.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 4a4f663b2bd2..d3b69eb3242b 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -1955,6 +1955,17 @@ static int npf_interception(struct kvm_vcpu *vcpu) if (WARN_ON_ONCE(error_code & PFERR_SYNTHETIC_MASK)) error_code &= ~PFERR_SYNTHETIC_MASK; + if ((svm->vmcb->control.nested_ctl & SVM_NESTED_CTL_GMET_ENABLE) && + (error_code & PFERR_FETCH_MASK)) { + /* + * Work around errata 1218: EXITINFO1[2] May Be Incorrectly Set + * When GMET (Guest Mode Execute Trap extension) is Enabled + */ + error_code |= PFERR_USER_MASK; + if (svm_get_cpl(vcpu) == 0) + error_code &= ~PFERR_USER_MASK; + } + if (sev_snp_guest(vcpu->kvm) && (error_code & PFERR_GUEST_ENC_MASK)) error_code |= PFERR_PRIVATE_ACCESS; -- 2.52.0