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. Tested-by: David Riley Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/svm.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 3895d8794366..fd79874c5f4b 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -1993,6 +1993,18 @@ static int npf_interception(struct kvm_vcpu *vcpu) } } + if (!is_sev_es_guest(vcpu) && + (svm->vmcb->control.misc_ctl & SVM_MISC_ENABLE_GMET) && + (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) != 3) + error_code &= ~PFERR_USER_MASK; + } + if (is_sev_snp_guest(vcpu) && (error_code & PFERR_GUEST_ENC_MASK)) error_code |= PFERR_PRIVATE_ACCESS; -- 2.54.0