KVM: x86: Simplify __apic_accept_irq

If posted interrupts are enabled, we can no longer track if an IRQ was
coalesced based on IRR. So drop this logic also from the classic
software path and simplify apic_test_and_set_irr to apic_set_irr.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>

arch/x86/kvm/lapic.c

@@ -331,10 +331,10 @@ void kvm_apic_update_irr(struct kvm_vcpu *vcpu, u32 *pir)
 }
 EXPORT_SYMBOL_GPL(kvm_apic_update_irr);
 
-static inline int apic_test_and_set_irr(int vec, struct kvm_lapic *apic)
+static inline void apic_set_irr(int vec, struct kvm_lapic *apic)
 {
 	apic->irr_pending = true;
-	return apic_test_and_set_vector(vec, apic->regs + APIC_IRR);
+	apic_set_vector(vec, apic->regs + APIC_IRR);
 }
 
 static inline int apic_search_irr(struct kvm_lapic *apic)
@@ -681,28 +681,21 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
 		if (unlikely(!apic_enabled(apic)))
 			break;
 
+		result = 1;
+
 		if (dest_map)
 			__set_bit(vcpu->vcpu_id, dest_map);
 
-		if (kvm_x86_ops->deliver_posted_interrupt) {
-			result = 1;
+		if (kvm_x86_ops->deliver_posted_interrupt)
 			kvm_x86_ops->deliver_posted_interrupt(vcpu, vector);
-		} else {
-			result = !apic_test_and_set_irr(vector, apic);
-
-			if (!result) {
-				if (trig_mode)
-					apic_debug("level trig mode repeatedly "
-						"for vector %d", vector);
-				goto out;
-			}
+		else {
+			apic_set_irr(vector, apic);
 
 			kvm_make_request(KVM_REQ_EVENT, vcpu);
 			kvm_vcpu_kick(vcpu);
 		}
-out:
 		trace_kvm_apic_accept_irq(vcpu->vcpu_id, delivery_mode,
-				trig_mode, vector, !result);
+					  trig_mode, vector, false);
 		break;
 
 	case APIC_DM_REMRD: