virtio/tools: add delayed interupt mode

Signed-off-by: Michael S. Tsirkin <[e-mail]>

tools/virtio/linux/virtio.h

···
 void virtqueue_disable_cb(struct virtqueue *vq);
 
 bool virtqueue_enable_cb(struct virtqueue *vq);
+bool virtqueue_enable_cb_delayed(struct virtqueue *vq);
 
 void *virtqueue_detach_unused_buf(struct virtqueue *vq);
 struct virtqueue *vring_new_virtqueue(unsigned int num,

tools/virtio/virtio_test.c

···
 		}
 }
 
-static void run_test(struct vdev_info *dev, struct vq_info *vq, int bufs)
+static void run_test(struct vdev_info *dev, struct vq_info *vq,
+		     bool delayed, int bufs)
 {
 	struct scatterlist sl;
 	long started = 0, completed = 0;
···
 		assert(started <= bufs);
 		if (completed == bufs)
 			break;
-		if (virtqueue_enable_cb(vq->vq)) {
-			wait_for_interrupt(dev);
+		if (delayed) {
+			if (virtqueue_enable_cb_delayed(vq->vq))
+				wait_for_interrupt(dev);
+		} else {
+			if (virtqueue_enable_cb(vq->vq))
+				wait_for_interrupt(dev);
 		}
 	}
 	test = 0;
···
 		.val = 'i',
 	},
 	{
+		.name = "delayed-interrupt",
+		.val = 'D',
+	},
+	{
+		.name = "no-delayed-interrupt",
+		.val = 'd',
+	},
+	{
 	}
 };
 
···
 	fprintf(stderr, "Usage: virtio_test [--help]"
 		" [--no-indirect]"
 		" [--no-event-idx]"
+		" [--delayed-interrupt]"
 		"\n");
 }
 
···
 	unsigned long long features = (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
 		(1ULL << VIRTIO_RING_F_EVENT_IDX);
 	int o;
+	bool delayed = false;
 
 	for (;;) {
 		o = getopt_long(argc, argv, optstring, longopts, NULL);
···
 		case 'i':
 			features &= ~(1ULL << VIRTIO_RING_F_INDIRECT_DESC);
 			break;
+		case 'D':
+			delayed = true;
+			break;
 		default:
 			assert(0);
 			break;
···
 done:
 	vdev_info_init(&dev, features);
 	vq_info_add(&dev, 256);
-	run_test(&dev, &dev.vqs[0], 0x100000);
+	run_test(&dev, &dev.vqs[0], delayed, 0x100000);
 	return 0;
 }