KVM: x86: make pic setup code look like ioapic setup

We don't treat kvm->arch.vpic specially anymore, so the setup can look
like ioapic.  This gets a bit more information out of return values.
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/i8259.c

@@ -598,14 +598,14 @@ static const struct kvm_io_device_ops picdev_eclr_ops = {
 	.write    = picdev_eclr_write,
 };
 
-struct kvm_pic *kvm_create_pic(struct kvm *kvm)
+int kvm_pic_init(struct kvm *kvm)
 {
 	struct kvm_pic *s;
 	int ret;
 
 	s = kzalloc(sizeof(struct kvm_pic), GFP_KERNEL);
 	if (!s)
-		return NULL;
+		return -ENOMEM;
 	spin_lock_init(&s->lock);
 	s->kvm = kvm;
 	s->pics[0].elcr_mask = 0xf8;
@@ -635,7 +635,9 @@ struct kvm_pic *kvm_create_pic(struct kvm *kvm)
 
 	mutex_unlock(&kvm->slots_lock);
 
-	return s;
+	kvm->arch.vpic = s;
+
+	return 0;
 
 fail_unreg_1:
 	kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &s->dev_slave);
@@ -648,13 +650,17 @@ struct kvm_pic *kvm_create_pic(struct kvm *kvm)
 
 	kfree(s);
 
-	return NULL;
+	return ret;
 }
 
-void kvm_destroy_pic(struct kvm_pic *vpic)
+void kvm_pic_destroy(struct kvm *kvm)
 {
+	struct kvm_pic *vpic = kvm->arch.vpic;
+
 	kvm_io_bus_unregister_dev(vpic->kvm, KVM_PIO_BUS, &vpic->dev_master);
 	kvm_io_bus_unregister_dev(vpic->kvm, KVM_PIO_BUS, &vpic->dev_slave);
 	kvm_io_bus_unregister_dev(vpic->kvm, KVM_PIO_BUS, &vpic->dev_eclr);
+
+	kvm->arch.vpic = NULL;
 	kfree(vpic);
 }

arch/x86/kvm/irq.h

@@ -73,8 +73,8 @@ struct kvm_pic {
 	unsigned long irq_states[PIC_NUM_PINS];
 };
 
-struct kvm_pic *kvm_create_pic(struct kvm *kvm);
-void kvm_destroy_pic(struct kvm_pic *vpic);
+int kvm_pic_init(struct kvm *kvm);
+void kvm_pic_destroy(struct kvm *kvm);
 int kvm_pic_read_irq(struct kvm *kvm);
 void kvm_pic_update_irq(struct kvm_pic *s);
 

arch/x86/kvm/x86.c

@@ -3957,33 +3957,34 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		r = kvm_vm_ioctl_get_nr_mmu_pages(kvm);
 		break;
 	case KVM_CREATE_IRQCHIP: {
-		struct kvm_pic *vpic;
-
 		mutex_lock(&kvm->lock);
+
 		r = -EEXIST;
 		if (irqchip_in_kernel(kvm))
 			goto create_irqchip_unlock;
+
 		r = -EINVAL;
 		if (kvm->created_vcpus)
 			goto create_irqchip_unlock;
-		r = -ENOMEM;
-		vpic = kvm_create_pic(kvm);
-		if (vpic) {
-			r = kvm_ioapic_init(kvm);
-			if (r) {
-				mutex_lock(&kvm->slots_lock);
-				kvm_destroy_pic(vpic);
-				mutex_unlock(&kvm->slots_lock);
-				goto create_irqchip_unlock;
-			}
-		} else
+
+		r = kvm_pic_init(kvm);
+		if (r)
 			goto create_irqchip_unlock;
+
+		r = kvm_ioapic_init(kvm);
+		if (r) {
+			mutex_lock(&kvm->slots_lock);
+			kvm_pic_destroy(kvm);
+			mutex_unlock(&kvm->slots_lock);
+			goto create_irqchip_unlock;
+		}
+
 		r = kvm_setup_default_irq_routing(kvm);
 		if (r) {
 			mutex_lock(&kvm->slots_lock);
 			mutex_lock(&kvm->irq_lock);
 			kvm_ioapic_destroy(kvm);
-			kvm_destroy_pic(vpic);
+			kvm_pic_destroy(kvm);
 			mutex_unlock(&kvm->irq_lock);
 			mutex_unlock(&kvm->slots_lock);
 			goto create_irqchip_unlock;
@@ -3991,7 +3992,6 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		/* Write kvm->irq_routing before enabling irqchip_in_kernel. */
 		smp_wmb();
 		kvm->arch.irqchip_mode = KVM_IRQCHIP_KERNEL;
-		kvm->arch.vpic = vpic;
 	create_irqchip_unlock:
 		mutex_unlock(&kvm->lock);
 		break;