KVM: Take missing slots_lock for kvm_io_bus_unregister_dev()

In KVM_CREATE_IRQCHIP, kvm_io_bus_unregister_dev() is called without taking
slots_lock in the error handling path.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/ia64/kvm/kvm-ia64.c

@@ -951,7 +951,9 @@ long kvm_arch_vm_ioctl(struct file *filp,
 			goto out;
 		r = kvm_setup_default_irq_routing(kvm);
 		if (r) {
+			mutex_lock(&kvm->slots_lock);
 			kvm_ioapic_destroy(kvm);
+			mutex_unlock(&kvm->slots_lock);
 			goto out;
 		}
 		break;

arch/x86/kvm/x86.c

@@ -3309,8 +3309,10 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		if (vpic) {
 			r = kvm_ioapic_init(kvm);
 			if (r) {
+				mutex_lock(&kvm->slots_lock);
 				kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS,
 							  &vpic->dev);
+				mutex_unlock(&kvm->slots_lock);
 				kfree(vpic);
 				goto create_irqchip_unlock;
 			}
@@ -3321,10 +3323,12 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		smp_wmb();
 		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(kvm);
 			mutex_unlock(&kvm->irq_lock);
+			mutex_unlock(&kvm->slots_lock);
 		}
 	create_irqchip_unlock:
 		mutex_unlock(&kvm->lock);