KVM: nVMX: Do not inject NMI vmexits when L2 has a pending interrupt

According to SDM 27.2.3, IDT vectoring information will not be valid on
vmexits caused by external NMIs. So we have to avoid creating such
scenarios by delaying EXIT_REASON_EXCEPTION_NMI injection as long as we
have a pending interrupt because that one would be migrated to L1's IDT
vectoring info on nested exit.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e559675e113f..2c9d21e2d033 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8176,7 +8176,8 @@ static int vmx_check_nested_events(struct kvm_vcpu *vcpu, bool external_intr)
         }
 
         if (vcpu->arch.nmi_pending && nested_exit_on_nmi(vcpu)) {
-                if (vmx->nested.nested_run_pending)
+                if (vmx->nested.nested_run_pending ||
+                    vcpu->arch.interrupt.pending)
                         return -EBUSY;
                 nested_vmx_vmexit(vcpu, EXIT_REASON_EXCEPTION_NMI,
                                   NMI_VECTOR | INTR_TYPE_NMI_INTR |