diff options
| -rw-r--r-- | arch/x86/kvm/svm/svm.c | 27 |
1 files changed, 19 insertions, 8 deletions
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index c8dc25886c16..1d3c8be39479 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -3846,16 +3846,27 @@ static void svm_enable_nmi_window(struct kvm_vcpu *vcpu) struct vcpu_svm *svm = to_svm(vcpu); /* - * KVM should never request an NMI window when vNMI is enabled, as KVM - * allows at most one to-be-injected NMI and one pending NMI, i.e. if - * two NMIs arrive simultaneously, KVM will inject one and set - * V_NMI_PENDING for the other. WARN, but continue with the standard - * single-step approach to try and salvage the pending NMI. + * If NMIs are outright masked, i.e. the vCPU is already handling an + * NMI, and KVM has not yet intercepted an IRET, then there is nothing + * more to do at this time as KVM has already enabled IRET intercepts. + * If KVM has already intercepted IRET, then single-step over the IRET, + * as NMIs aren't architecturally unmasked until the IRET completes. + * + * If vNMI is enabled, KVM should never request an NMI window if NMIs + * are masked, as KVM allows at most one to-be-injected NMI and one + * pending NMI. If two NMIs arrive simultaneously, KVM will inject one + * NMI and set V_NMI_PENDING for the other, but if and only if NMIs are + * unmasked. KVM _will_ request an NMI window in some situations, e.g. + * if the vCPU is in an STI shadow or if GIF=0, KVM can't immediately + * inject the NMI. In those situations, KVM needs to single-step over + * the STI shadow or intercept STGI. */ - WARN_ON_ONCE(is_vnmi_enabled(svm)); + if (svm_get_nmi_mask(vcpu)) { + WARN_ON_ONCE(is_vnmi_enabled(svm)); - if (svm_get_nmi_mask(vcpu) && !svm->awaiting_iret_completion) - return; /* IRET will cause a vm exit */ + if (!svm->awaiting_iret_completion) + return; /* IRET will cause a vm exit */ + } /* * SEV-ES guests are responsible for signaling when a vCPU is ready to |