KVM: nVMX: Preserve IRQ/NMI priority irrespective of exiting behavior

Short circuit vmx_check_nested_events() if an unblocked IRQ/NMI is
pending and needs to be injected into L2, priority between coincident
events is not dependent on exiting behavior.

Fixes: b6b8a145 ("KVM: nVMX: Rework interception of IRQs and NMIs")
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200423022550.15113-9-sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx/nested.c

@@ -3750,9 +3750,12 @@ static int vmx_check_nested_events(struct kvm_vcpu *vcpu)
 		return 0;
 	}
 
-	if (vcpu->arch.nmi_pending && nested_exit_on_nmi(vcpu)) {
+	if (vcpu->arch.nmi_pending && !vmx_nmi_blocked(vcpu)) {
 		if (block_nested_events)
 			return -EBUSY;
+		if (!nested_exit_on_nmi(vcpu))
+			goto no_vmexit;
+
 		nested_vmx_vmexit(vcpu, EXIT_REASON_EXCEPTION_NMI,
 				  NMI_VECTOR | INTR_TYPE_NMI_INTR |
 				  INTR_INFO_VALID_MASK, 0);
@@ -3765,9 +3768,11 @@ static int vmx_check_nested_events(struct kvm_vcpu *vcpu)
 		return 0;
 	}
 
-	if (kvm_cpu_has_interrupt(vcpu) && nested_exit_on_intr(vcpu)) {
+	if (kvm_cpu_has_interrupt(vcpu) && !vmx_interrupt_blocked(vcpu)) {
 		if (block_nested_events)
 			return -EBUSY;
+		if (!nested_exit_on_intr(vcpu))
+			goto no_vmexit;
 		nested_vmx_vmexit(vcpu, EXIT_REASON_EXTERNAL_INTERRUPT, 0, 0);
 		return 0;
 	}