Merge branch 'virtio' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus

* 'virtio' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus: (27 commits)
drivers/char: Eliminate use after free
virtio: console: Accept console size along with resize control message
virtio: console: Store each console's size in the console structure
virtio: console: Resize console port 0 on config intr only if multiport is off
virtio: console: Add support for nonblocking write()s
virtio: console: Rename wait_is_over() to will_read_block()
virtio: console: Don't always create a port 0 if using multiport
virtio: console: Use a control message to add ports
virtio: console: Move code around for future patches
virtio: console: Remove config work handler
virtio: console: Don't call hvc_remove() on unplugging console ports
virtio: console: Return -EPIPE to hvc_console if we lost the connection
virtio: console: Let host know of port or device add failures
virtio: console: Add a __send_control_msg() that can send messages without a valid port
virtio: Revert "virtio: disable multiport console support."
virtio: add_buf_gfp
trans_virtio: use virtqueue_xxx wrappers
virtio-rng: use virtqueue_xxx wrappers
virtio_ring: remove a level of indirection
virtio_net: use virtqueue_xxx wrappers
...

Fix up conflicts in drivers/net/virtio_net.c due to new virtqueue_xxx
wrappers changes conflicting with some other cleanups.

drivers/block/virtio_blk.c

···
 	unsigned long flags;
 
 	spin_lock_irqsave(&vblk->lock, flags);
-	while ((vbr = vblk->vq->vq_ops->get_buf(vblk->vq, &len)) != NULL) {
+	while ((vbr = virtqueue_get_buf(vblk->vq, &len)) != NULL) {
 		int error;
 
 		switch (vbr->status) {
···
 			vbr->req->sense_len = vbr->in_hdr.sense_len;
 			vbr->req->errors = vbr->in_hdr.errors;
 		}
+		if (blk_special_request(vbr->req))
+			vbr->req->errors = (error != 0);
 
 		__blk_end_request_all(vbr->req, error);
 		list_del(&vbr->list);
···
 		break;
 	case REQ_TYPE_BLOCK_PC:
 		vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD;
+		vbr->out_hdr.sector = 0;
+		vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
+		break;
+	case REQ_TYPE_SPECIAL:
+		vbr->out_hdr.type = VIRTIO_BLK_T_GET_ID;
 		vbr->out_hdr.sector = 0;
 		vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
 		break;
···
 		}
 	}
 
-	if (vblk->vq->vq_ops->add_buf(vblk->vq, vblk->sg, out, in, vbr) < 0) {
+	if (virtqueue_add_buf(vblk->vq, vblk->sg, out, in, vbr) < 0) {
 		mempool_free(vbr, vblk->pool);
 		return false;
 	}
···
 	}
 
 	if (issued)
-		vblk->vq->vq_ops->kick(vblk->vq);
+		virtqueue_kick(vblk->vq);
 }
 
 static void virtblk_prepare_flush(struct request_queue *q, struct request *req)
···
 	req->cmd[0] = REQ_LB_OP_FLUSH;
 }
 
+/* return id (s/n) string for *disk to *id_str
+ */
+static int virtblk_get_id(struct gendisk *disk, char *id_str)
+{
+	struct virtio_blk *vblk = disk->private_data;
+	struct request *req;
+	struct bio *bio;
+
+	bio = bio_map_kern(vblk->disk->queue, id_str, VIRTIO_BLK_ID_BYTES,
+			   GFP_KERNEL);
+	if (IS_ERR(bio))
+		return PTR_ERR(bio);
+
+	req = blk_make_request(vblk->disk->queue, bio, GFP_KERNEL);
+	if (IS_ERR(req)) {
+		bio_put(bio);
+		return PTR_ERR(req);
+	}
+
+	req->cmd_type = REQ_TYPE_SPECIAL;
+	return blk_execute_rq(vblk->disk->queue, vblk->disk, req, false);
+}
+
 static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
 			 unsigned cmd, unsigned long data)
 {
 	struct gendisk *disk = bdev->bd_disk;
 	struct virtio_blk *vblk = disk->private_data;
 
+	if (cmd == 0x56424944) { /* 'VBID' */
+		void __user *usr_data = (void __user *)data;
+		char id_str[VIRTIO_BLK_ID_BYTES];
+		int err;
+
+		err = virtblk_get_id(disk, id_str);
+		if (!err && copy_to_user(usr_data, id_str, VIRTIO_BLK_ID_BYTES))
+			err = -EFAULT;
+		return err;
+	}
 	/*
 	 * Only allow the generic SCSI ioctls if the host can support it.
 	 */

drivers/char/hw_random/virtio-rng.c

···
 static void random_recv_done(struct virtqueue *vq)
 {
 	/* We can get spurious callbacks, e.g. shared IRQs + virtio_pci. */
-	if (!vq->vq_ops->get_buf(vq, &data_avail))
+	if (!virtqueue_get_buf(vq, &data_avail))
 		return;
 
 	complete(&have_data);
···
 	sg_init_one(&sg, buf, size);
 
 	/* There should always be room for one buffer. */
-	if (vq->vq_ops->add_buf(vq, &sg, 0, 1, buf) < 0)
+	if (virtqueue_add_buf(vq, &sg, 0, 1, buf) < 0)
 		BUG();
 
-	vq->vq_ops->kick(vq);
+	virtqueue_kick(vq);
 }
 
 static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait)

drivers/char/virtio_console.c

···
 #include <linux/workqueue.h>
 #include "hvc_console.h"
 
-/* Moved here from .h file in order to disable MULTIPORT. */
-#define VIRTIO_CONSOLE_F_MULTIPORT 1	/* Does host provide multiple ports? */
-
-struct virtio_console_multiport_conf {
-	struct virtio_console_config config;
-	/* max. number of ports this device can hold */
-	__u32 max_nr_ports;
-	/* number of ports added so far */
-	__u32 nr_ports;
-} __attribute__((packed));
-
-/*
- * A message that's passed between the Host and the Guest for a
- * particular port.
- */
-struct virtio_console_control {
-	__u32 id;		/* Port number */
-	__u16 event;		/* The kind of control event (see below) */
-	__u16 value;		/* Extra information for the key */
-};
-
-/* Some events for control messages */
-#define VIRTIO_CONSOLE_PORT_READY	0
-#define VIRTIO_CONSOLE_CONSOLE_PORT	1
-#define VIRTIO_CONSOLE_RESIZE		2
-#define VIRTIO_CONSOLE_PORT_OPEN	3
-#define VIRTIO_CONSOLE_PORT_NAME	4
-#define VIRTIO_CONSOLE_PORT_REMOVE	5
-
 /*
  * This is a global struct for storing common data for all the devices
  * this driver handles.
···
 	/* The hvc device associated with this console port */
 	struct hvc_struct *hvc;
 
+	/* The size of the console */
+	struct winsize ws;
+
 	/*
 	 * This number identifies the number that we used to register
 	 * with hvc in hvc_instantiate() and hvc_alloc(); this is the
···
 	 * notification
 	 */
 	struct work_struct control_work;
-	struct work_struct config_work;
 
 	struct list_head ports;
 
···
 	spinlock_t cvq_lock;
 
 	/* The current config space is stored here */
-	struct virtio_console_multiport_conf config;
+	struct virtio_console_config config;
 
 	/* The virtio device we're associated with */
 	struct virtio_device *vdev;
···
 	 */
 	spinlock_t inbuf_lock;
 
+	/* Protect the operations on the out_vq. */
+	spinlock_t outvq_lock;
+
 	/* The IO vqs for this port */
 	struct virtqueue *in_vq, *out_vq;
 
···
 
 	/* The 'id' to identify the port with the Host */
 	u32 id;
+
+	bool outvq_full;
 
 	/* Is the host device open */
 	bool host_connected;
···
 	unsigned int len;
 
 	vq = port->in_vq;
-	buf = vq->vq_ops->get_buf(vq, &len);
+	buf = virtqueue_get_buf(vq, &len);
 	if (buf) {
 		buf->len = len;
 		buf->offset = 0;
···
 
 	sg_init_one(sg, buf->buf, buf->size);
 
-	ret = vq->vq_ops->add_buf(vq, sg, 0, 1, buf);
-	vq->vq_ops->kick(vq);
+	ret = virtqueue_add_buf(vq, sg, 0, 1, buf);
+	virtqueue_kick(vq);
 	return ret;
 }
 
···
 	if (port->inbuf)
 		buf = port->inbuf;
 	else
-		buf = vq->vq_ops->get_buf(vq, &len);
+		buf = virtqueue_get_buf(vq, &len);
 
 	ret = 0;
 	while (buf) {
···
 			ret++;
 			free_buf(buf);
 		}
-		buf = vq->vq_ops->get_buf(vq, &len);
+		buf = virtqueue_get_buf(vq, &len);
 	}
 	port->inbuf = NULL;
 	if (ret)
···
 	return ret;
 }
 
-static ssize_t send_control_msg(struct port *port, unsigned int event,
-				unsigned int value)
+static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id,
+				  unsigned int event, unsigned int value)
 {
 	struct scatterlist sg[1];
 	struct virtio_console_control cpkt;
 	struct virtqueue *vq;
 	unsigned int len;
 
-	if (!use_multiport(port->portdev))
+	if (!use_multiport(portdev))
 		return 0;
 
-	cpkt.id = port->id;
+	cpkt.id = port_id;
 	cpkt.event = event;
 	cpkt.value = value;
 
-	vq = port->portdev->c_ovq;
+	vq = portdev->c_ovq;
 
 	sg_init_one(sg, &cpkt, sizeof(cpkt));
-	if (vq->vq_ops->add_buf(vq, sg, 1, 0, &cpkt) >= 0) {
-		vq->vq_ops->kick(vq);
-		while (!vq->vq_ops->get_buf(vq, &len))
+	if (virtqueue_add_buf(vq, sg, 1, 0, &cpkt) >= 0) {
+		virtqueue_kick(vq);
+		while (!virtqueue_get_buf(vq, &len))
 			cpu_relax();
 	}
 	return 0;
 }
 
-static ssize_t send_buf(struct port *port, void *in_buf, size_t in_count)
+static ssize_t send_control_msg(struct port *port, unsigned int event,
+				unsigned int value)
+{
+	return __send_control_msg(port->portdev, port->id, event, value);
+}
+
+/* Callers must take the port->outvq_lock */
+static void reclaim_consumed_buffers(struct port *port)
+{
+	void *buf;
+	unsigned int len;
+
+	while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
+		kfree(buf);
+		port->outvq_full = false;
+	}
+}
+
+static ssize_t send_buf(struct port *port, void *in_buf, size_t in_count,
+			bool nonblock)
 {
 	struct scatterlist sg[1];
 	struct virtqueue *out_vq;
 	ssize_t ret;
+	unsigned long flags;
 	unsigned int len;
 
 	out_vq = port->out_vq;
 
+	spin_lock_irqsave(&port->outvq_lock, flags);
+
+	reclaim_consumed_buffers(port);
+
 	sg_init_one(sg, in_buf, in_count);
-	ret = out_vq->vq_ops->add_buf(out_vq, sg, 1, 0, in_buf);
+	ret = virtqueue_add_buf(out_vq, sg, 1, 0, in_buf);
 
 	/* Tell Host to go! */
-	out_vq->vq_ops->kick(out_vq);
+	virtqueue_kick(out_vq);
 
 	if (ret < 0) {
 		in_count = 0;
-		goto fail;
+		goto done;
 	}
 
-	/* Wait till the host acknowledges it pushed out the data we sent. */
-	while (!out_vq->vq_ops->get_buf(out_vq, &len))
+	if (ret == 0)
+		port->outvq_full = true;
+
+	if (nonblock)
+		goto done;
+
+	/*
+	 * Wait till the host acknowledges it pushed out the data we
+	 * sent.  This is done for ports in blocking mode or for data
+	 * from the hvc_console; the tty operations are performed with
+	 * spinlocks held so we can't sleep here.
+	 */
+	while (!virtqueue_get_buf(out_vq, &len))
 		cpu_relax();
-fail:
-	/* We're expected to return the amount of data we wrote */
+done:
+	spin_unlock_irqrestore(&port->outvq_lock, flags);
+	/*
+	 * We're expected to return the amount of data we wrote -- all
+	 * of it
+	 */
 	return in_count;
 }
 
···
 }
 
 /* The condition that must be true for polling to end */
-static bool wait_is_over(struct port *port)
+static bool will_read_block(struct port *port)
 {
-	return port_has_data(port) || !port->host_connected;
+	return !port_has_data(port) && port->host_connected;
+}
+
+static bool will_write_block(struct port *port)
+{
+	bool ret;
+
+	if (!port->host_connected)
+		return true;
+
+	spin_lock_irq(&port->outvq_lock);
+	/*
+	 * Check if the Host has consumed any buffers since we last
+	 * sent data (this is only applicable for nonblocking ports).
+	 */
+	reclaim_consumed_buffers(port);
+	ret = port->outvq_full;
+	spin_unlock_irq(&port->outvq_lock);
+
+	return ret;
 }
 
 static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
···
 			return -EAGAIN;
 
 		ret = wait_event_interruptible(port->waitqueue,
-					       wait_is_over(port));
+					       !will_read_block(port));
 		if (ret < 0)
 			return ret;
 	}
···
 	struct port *port;
 	char *buf;
 	ssize_t ret;
+	bool nonblock;
 
 	port = filp->private_data;
+
+	nonblock = filp->f_flags & O_NONBLOCK;
+
+	if (will_write_block(port)) {
+		if (nonblock)
+			return -EAGAIN;
+
+		ret = wait_event_interruptible(port->waitqueue,
+					       !will_write_block(port));
+		if (ret < 0)
+			return ret;
+	}
 
 	count = min((size_t)(32 * 1024), count);
 
···
 		goto free_buf;
 	}
 
-	ret = send_buf(port, buf, count);
+	ret = send_buf(port, buf, count, nonblock);
+
+	if (nonblock && ret > 0)
+		goto out;
+
 free_buf:
 	kfree(buf);
+out:
 	return ret;
 }
 
···
 	ret = 0;
 	if (port->inbuf)
 		ret |= POLLIN | POLLRDNORM;
-	if (port->host_connected)
+	if (!will_write_block(port))
 		ret |= POLLOUT;
 	if (!port->host_connected)
 		ret |= POLLHUP;
···
 	discard_port_data(port);
 
 	spin_unlock_irq(&port->inbuf_lock);
+
+	spin_lock_irq(&port->outvq_lock);
+	reclaim_consumed_buffers(port);
+	spin_unlock_irq(&port->outvq_lock);
 
 	return 0;
 }
···
 
 	port->guest_connected = true;
 	spin_unlock_irq(&port->inbuf_lock);
+
+	spin_lock_irq(&port->outvq_lock);
+	/*
+	 * There might be a chance that we missed reclaiming a few
+	 * buffers in the window of the port getting previously closed
+	 * and opening now.
+	 */
+	reclaim_consumed_buffers(port);
+	spin_unlock_irq(&port->outvq_lock);
 
 	/* Notify host of port being opened */
 	send_control_msg(filp->private_data, VIRTIO_CONSOLE_PORT_OPEN, 1);
···
 
 	port = find_port_by_vtermno(vtermno);
 	if (!port)
-		return 0;
+		return -EPIPE;
 
-	return send_buf(port, (void *)buf, count);
+	return send_buf(port, (void *)buf, count, false);
 }
 
 /*
···
 {
 	struct port *port;
 
+	/* If we've not set up the port yet, we have no input to give. */
+	if (unlikely(early_put_chars))
+		return 0;
+
 	port = find_port_by_vtermno(vtermno);
 	if (!port)
-		return 0;
+		return -EPIPE;
 
 	/* If we don't have an input queue yet, we can't get input. */
 	BUG_ON(!port->in_vq);
···
 static void resize_console(struct port *port)
 {
 	struct virtio_device *vdev;
-	struct winsize ws;
 
 	/* The port could have been hot-unplugged */
-	if (!port)
+	if (!port || !is_console_port(port))
 		return;
 
 	vdev = port->portdev->vdev;
-	if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE)) {
-		vdev->config->get(vdev,
-				  offsetof(struct virtio_console_config, cols),
-				  &ws.ws_col, sizeof(u16));
-		vdev->config->get(vdev,
-				  offsetof(struct virtio_console_config, rows),
-				  &ws.ws_row, sizeof(u16));
-		hvc_resize(port->cons.hvc, ws);
-	}
+	if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
+		hvc_resize(port->cons.hvc, port->cons.ws);
 }
 
 /* We set the configuration at this point, since we now have a tty */
···
 	spin_unlock_irq(&pdrvdata_lock);
 	port->guest_connected = true;
 
+	/*
+	 * Start using the new console output if this is the first
+	 * console to come up.
+	 */
+	if (early_put_chars)
+		early_put_chars = NULL;
+
 	/* Notify host of port being opened */
 	send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
 
···
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 			       "host_connected: %d\n", port->host_connected);
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "outvq_full: %d\n", port->outvq_full);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 			       "is_console: %s\n",
 			       is_console_port(port) ? "yes" : "no");
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
···
 	.read  = debugfs_read,
 };
 
+static void set_console_size(struct port *port, u16 rows, u16 cols)
+{
+	if (!port || !is_console_port(port))
+		return;
+
+	port->cons.ws.ws_row = rows;
+	port->cons.ws.ws_col = cols;
+}
+
+static unsigned int fill_queue(struct virtqueue *vq, spinlock_t *lock)
+{
+	struct port_buffer *buf;
+	unsigned int nr_added_bufs;
+	int ret;
+
+	nr_added_bufs = 0;
+	do {
+		buf = alloc_buf(PAGE_SIZE);
+		if (!buf)
+			break;
+
+		spin_lock_irq(lock);
+		ret = add_inbuf(vq, buf);
+		if (ret < 0) {
+			spin_unlock_irq(lock);
+			free_buf(buf);
+			break;
+		}
+		nr_added_bufs++;
+		spin_unlock_irq(lock);
+	} while (ret > 0);
+
+	return nr_added_bufs;
+}
+
+static int add_port(struct ports_device *portdev, u32 id)
+{
+	char debugfs_name[16];
+	struct port *port;
+	struct port_buffer *buf;
+	dev_t devt;
+	unsigned int nr_added_bufs;
+	int err;
+
+	port = kmalloc(sizeof(*port), GFP_KERNEL);
+	if (!port) {
+		err = -ENOMEM;
+		goto fail;
+	}
+
+	port->portdev = portdev;
+	port->id = id;
+
+	port->name = NULL;
+	port->inbuf = NULL;
+	port->cons.hvc = NULL;
+
+	port->cons.ws.ws_row = port->cons.ws.ws_col = 0;
+
+	port->host_connected = port->guest_connected = false;
+
+	port->outvq_full = false;
+
+	port->in_vq = portdev->in_vqs[port->id];
+	port->out_vq = portdev->out_vqs[port->id];
+
+	cdev_init(&port->cdev, &port_fops);
+
+	devt = MKDEV(portdev->chr_major, id);
+	err = cdev_add(&port->cdev, devt, 1);
+	if (err < 0) {
+		dev_err(&port->portdev->vdev->dev,
+			"Error %d adding cdev for port %u\n", err, id);
+		goto free_port;
+	}
+	port->dev = device_create(pdrvdata.class, &port->portdev->vdev->dev,
+				  devt, port, "vport%up%u",
+				  port->portdev->drv_index, id);
+	if (IS_ERR(port->dev)) {
+		err = PTR_ERR(port->dev);
+		dev_err(&port->portdev->vdev->dev,
+			"Error %d creating device for port %u\n",
+			err, id);
+		goto free_cdev;
+	}
+
+	spin_lock_init(&port->inbuf_lock);
+	spin_lock_init(&port->outvq_lock);
+	init_waitqueue_head(&port->waitqueue);
+
+	/* Fill the in_vq with buffers so the host can send us data. */
+	nr_added_bufs = fill_queue(port->in_vq, &port->inbuf_lock);
+	if (!nr_added_bufs) {
+		dev_err(port->dev, "Error allocating inbufs\n");
+		err = -ENOMEM;
+		goto free_device;
+	}
+
+	/*
+	 * If we're not using multiport support, this has to be a console port
+	 */
+	if (!use_multiport(port->portdev)) {
+		err = init_port_console(port);
+		if (err)
+			goto free_inbufs;
+	}
+
+	spin_lock_irq(&portdev->ports_lock);
+	list_add_tail(&port->list, &port->portdev->ports);
+	spin_unlock_irq(&portdev->ports_lock);
+
+	/*
+	 * Tell the Host we're set so that it can send us various
+	 * configuration parameters for this port (eg, port name,
+	 * caching, whether this is a console port, etc.)
+	 */
+	send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
+
+	if (pdrvdata.debugfs_dir) {
+		/*
+		 * Finally, create the debugfs file that we can use to
+		 * inspect a port's state at any time
+		 */
+		sprintf(debugfs_name, "vport%up%u",
+			port->portdev->drv_index, id);
+		port->debugfs_file = debugfs_create_file(debugfs_name, 0444,
+							 pdrvdata.debugfs_dir,
+							 port,
+							 &port_debugfs_ops);
+	}
+	return 0;
+
+free_inbufs:
+	while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
+		free_buf(buf);
+free_device:
+	device_destroy(pdrvdata.class, port->dev->devt);
+free_cdev:
+	cdev_del(&port->cdev);
+free_port:
+	kfree(port);
+fail:
+	/* The host might want to notify management sw about port add failure */
+	__send_control_msg(portdev, id, VIRTIO_CONSOLE_PORT_READY, 0);
+	return err;
+}
+
 /* Remove all port-specific data. */
 static int remove_port(struct port *port)
 {
···
 		spin_lock_irq(&pdrvdata_lock);
 		list_del(&port->cons.list);
 		spin_unlock_irq(&pdrvdata_lock);
+#if 0
+		/*
+		 * hvc_remove() not called as removing one hvc port
+		 * results in other hvc ports getting frozen.
+		 *
+		 * Once this is resolved in hvc, this functionality
+		 * will be enabled.  Till that is done, the -EPIPE
+		 * return from get_chars() above will help
+		 * hvc_console.c to clean up on ports we remove here.
+		 */
 		hvc_remove(port->cons.hvc);
+#endif
 	}
 	if (port->guest_connected)
 		send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
···
 	/* Remove unused data this port might have received. */
 	discard_port_data(port);
 
+	reclaim_consumed_buffers(port);
+
 	/* Remove buffers we queued up for the Host to send us data in. */
-	while ((buf = port->in_vq->vq_ops->detach_unused_buf(port->in_vq)))
+	while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
 		free_buf(buf);
 
 	kfree(port->name);
···
 	cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
 
 	port = find_port_by_id(portdev, cpkt->id);
-	if (!port) {
+	if (!port && cpkt->event != VIRTIO_CONSOLE_PORT_ADD) {
 		/* No valid header at start of buffer.  Drop it. */
 		dev_dbg(&portdev->vdev->dev,
 			"Invalid index %u in control packet\n", cpkt->id);
···
 	}
 
 	switch (cpkt->event) {
+	case VIRTIO_CONSOLE_PORT_ADD:
+		if (port) {
+			dev_dbg(&portdev->vdev->dev,
+				"Port %u already added\n", port->id);
+			send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
+			break;
+		}
+		if (cpkt->id >= portdev->config.max_nr_ports) {
+			dev_warn(&portdev->vdev->dev,
+				"Request for adding port with out-of-bound id %u, max. supported id: %u\n",
+				cpkt->id, portdev->config.max_nr_ports - 1);
+			break;
+		}
+		add_port(portdev, cpkt->id);
+		break;
+	case VIRTIO_CONSOLE_PORT_REMOVE:
+		remove_port(port);
+		break;
 	case VIRTIO_CONSOLE_CONSOLE_PORT:
 		if (!cpkt->value)
 			break;
···
 		 * have to notify the host first.
 		 */
 		break;
-	case VIRTIO_CONSOLE_RESIZE:
+	case VIRTIO_CONSOLE_RESIZE: {
+		struct {
+			__u16 rows;
+			__u16 cols;
+		} size;
+
 		if (!is_console_port(port))
 			break;
+
+		memcpy(&size, buf->buf + buf->offset + sizeof(*cpkt),
+		       sizeof(size));
+		set_console_size(port, size.rows, size.cols);
+
 		port->cons.hvc->irq_requested = 1;
 		resize_console(port);
 		break;
+	}
 	case VIRTIO_CONSOLE_PORT_OPEN:
 		port->host_connected = cpkt->value;
 		wake_up_interruptible(&port->waitqueue);
+		/*
+		 * If the host port got closed and the host had any
+		 * unconsumed buffers, we'll be able to reclaim them
+		 * now.
+		 */
+		spin_lock_irq(&port->outvq_lock);
+		reclaim_consumed_buffers(port);
+		spin_unlock_irq(&port->outvq_lock);
 		break;
 	case VIRTIO_CONSOLE_PORT_NAME:
 		/*
···
 			kobject_uevent(&port->dev->kobj, KOBJ_CHANGE);
 		}
 		break;
-	case VIRTIO_CONSOLE_PORT_REMOVE:
-		/*
-		 * Hot unplug the port.  We don't decrement nr_ports
-		 * since we don't want to deal with extra complexities
-		 * of using the lowest-available port id: We can just
-		 * pick up the nr_ports number as the id and not have
-		 * userspace send it to us.  This helps us in two
-		 * ways:
-		 *
-		 * - We don't need to have a 'port_id' field in the
-		 *   config space when a port is hot-added.  This is a
-		 *   good thing as we might queue up multiple hotplug
-		 *   requests issued in our workqueue.
-		 *
-		 * - Another way to deal with this would have been to
-		 *   use a bitmap of the active ports and select the
-		 *   lowest non-active port from that map.  That
-		 *   bloats the already tight config space and we
-		 *   would end up artificially limiting the
-		 *   max. number of ports to sizeof(bitmap).  Right
-		 *   now we can support 2^32 ports (as the port id is
-		 *   stored in a u32 type).
-		 *
-		 */
-		remove_port(port);
-		break;
 	}
 }
 
···
 	vq = portdev->c_ivq;
 
 	spin_lock(&portdev->cvq_lock);
-	while ((buf = vq->vq_ops->get_buf(vq, &len))) {
+	while ((buf = virtqueue_get_buf(vq, &len))) {
 		spin_unlock(&portdev->cvq_lock);
 
 		buf->len = len;
···
 	struct ports_device *portdev;
 
 	portdev = vdev->priv;
-	if (use_multiport(portdev)) {
-		/* Handle port hot-add */
-		schedule_work(&portdev->config_work);
-	}
-	/*
-	 * We'll use this way of resizing only for legacy support.
-	 * For newer userspace (VIRTIO_CONSOLE_F_MULTPORT+), use
-	 * control messages to indicate console size changes so that
-	 * it can be done per-port
-	 */
-	resize_console(find_port_by_id(portdev, 0));
-}
 
-static unsigned int fill_queue(struct virtqueue *vq, spinlock_t *lock)
-{
-	struct port_buffer *buf;
-	unsigned int nr_added_bufs;
-	int ret;
-
-	nr_added_bufs = 0;
-	do {
-		buf = alloc_buf(PAGE_SIZE);
-		if (!buf)
-			break;
-
-		spin_lock_irq(lock);
-		ret = add_inbuf(vq, buf);
-		if (ret < 0) {
-			spin_unlock_irq(lock);
-			free_buf(buf);
-			break;
-		}
-		nr_added_bufs++;
-		spin_unlock_irq(lock);
-	} while (ret > 0);
-
-	return nr_added_bufs;
-}
-
-static int add_port(struct ports_device *portdev, u32 id)
-{
-	char debugfs_name[16];
-	struct port *port;
-	struct port_buffer *buf;
-	dev_t devt;
-	unsigned int nr_added_bufs;
-	int err;
-
-	port = kmalloc(sizeof(*port), GFP_KERNEL);
-	if (!port) {
-		err = -ENOMEM;
-		goto fail;
-	}
-
-	port->portdev = portdev;
-	port->id = id;
-
-	port->name = NULL;
-	port->inbuf = NULL;
-	port->cons.hvc = NULL;
-
-	port->host_connected = port->guest_connected = false;
-
-	port->in_vq = portdev->in_vqs[port->id];
-	port->out_vq = portdev->out_vqs[port->id];
-
-	cdev_init(&port->cdev, &port_fops);
-
-	devt = MKDEV(portdev->chr_major, id);
-	err = cdev_add(&port->cdev, devt, 1);
-	if (err < 0) {
-		dev_err(&port->portdev->vdev->dev,
-			"Error %d adding cdev for port %u\n", err, id);
-		goto free_port;
-	}
-	port->dev = device_create(pdrvdata.class, &port->portdev->vdev->dev,
-				  devt, port, "vport%up%u",
-				  port->portdev->drv_index, id);
-	if (IS_ERR(port->dev)) {
-		err = PTR_ERR(port->dev);
-		dev_err(&port->portdev->vdev->dev,
-			"Error %d creating device for port %u\n",
-			err, id);
-		goto free_cdev;
-	}
-
-	spin_lock_init(&port->inbuf_lock);
-	init_waitqueue_head(&port->waitqueue);
-
-	/* Fill the in_vq with buffers so the host can send us data. */
-	nr_added_bufs = fill_queue(port->in_vq, &port->inbuf_lock);
-	if (!nr_added_bufs) {
-		dev_err(port->dev, "Error allocating inbufs\n");
-		err = -ENOMEM;
-		goto free_device;
-	}
-
-	/*
-	 * If we're not using multiport support, this has to be a console port
-	 */
-	if (!use_multiport(port->portdev)) {
-		err = init_port_console(port);
-		if (err)
-			goto free_inbufs;
-	}
-
-	spin_lock_irq(&portdev->ports_lock);
-	list_add_tail(&port->list, &port->portdev->ports);
-	spin_unlock_irq(&portdev->ports_lock);
-
-	/*
-	 * Tell the Host we're set so that it can send us various
-	 * configuration parameters for this port (eg, port name,
-	 * caching, whether this is a console port, etc.)
-	 */
-	send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
-
-	if (pdrvdata.debugfs_dir) {
-		/*
-		 * Finally, create the debugfs file that we can use to
-		 * inspect a port's state at any time
-		 */
-		sprintf(debugfs_name, "vport%up%u",
-			port->portdev->drv_index, id);
-		port->debugfs_file = debugfs_create_file(debugfs_name, 0444,
-							 pdrvdata.debugfs_dir,
-							 port,
-							 &port_debugfs_ops);
-	}
-	return 0;
-
-free_inbufs:
-	while ((buf = port->in_vq->vq_ops->detach_unused_buf(port->in_vq)))
-		free_buf(buf);
-free_device:
-	device_destroy(pdrvdata.class, port->dev->devt);
-free_cdev:
-	cdev_del(&port->cdev);
-free_port:
-	kfree(port);
-fail:
-	return err;
-}
-
-/*
- * The workhandler for config-space updates.
- *
- * This is called when ports are hot-added.
- */
-static void config_work_handler(struct work_struct *work)
-{
-	struct virtio_console_multiport_conf virtconconf;
-	struct ports_device *portdev;
-	struct virtio_device *vdev;
-	int err;
-
-	portdev = container_of(work, struct ports_device, config_work);
-
-	vdev = portdev->vdev;
-	vdev->config->get(vdev,
-			  offsetof(struct virtio_console_multiport_conf,
-				   nr_ports),
-			  &virtconconf.nr_ports,
-			  sizeof(virtconconf.nr_ports));
-
-	if (portdev->config.nr_ports == virtconconf.nr_ports) {
-		/*
-		 * Port 0 got hot-added.  Since we already did all the
-		 * other initialisation for it, just tell the Host
-		 * that the port is ready if we find the port.  In
-		 * case the port was hot-removed earlier, we call
-		 * add_port to add the port.
-		 */
+	if (!use_multiport(portdev)) {
 		struct port *port;
+		u16 rows, cols;
+
+		vdev->config->get(vdev,
+				  offsetof(struct virtio_console_config, cols),
+				  &cols, sizeof(u16));
+		vdev->config->get(vdev,
+				  offsetof(struct virtio_console_config, rows),
+				  &rows, sizeof(u16));
 
 		port = find_port_by_id(portdev, 0);
-		if (!port)
-			add_port(portdev, 0);
-		else
-			send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
-		return;
-	}
-	if (virtconconf.nr_ports > portdev->config.max_nr_ports) {
-		dev_warn(&vdev->dev,
-			 "More ports specified (%u) than allowed (%u)",
-			 portdev->config.nr_ports + 1,
-			 portdev->config.max_nr_ports);
-		return;
-	}
-	if (virtconconf.nr_ports < portdev->config.nr_ports)
-		return;
+		set_console_size(port, rows, cols);
 
-	/* Hot-add ports */
-	while (virtconconf.nr_ports - portdev->config.nr_ports) {
-		err = add_port(portdev, portdev->config.nr_ports);
-		if (err)
-			break;
-		portdev->config.nr_ports++;
+		/*
+		 * We'll use this way of resizing only for legacy
+		 * support.  For newer userspace
+		 * (VIRTIO_CONSOLE_F_MULTPORT+), use control messages
+		 * to indicate console size changes so that it can be
+		 * done per-port.
+		 */
+		resize_console(port);
 	}
 }
 
···
 static int __devinit virtcons_probe(struct virtio_device *vdev)
 {
 	struct ports_device *portdev;
-	u32 i;
 	int err;
 	bool multiport;
 
···
 	}
 
 	multiport = false;
-	portdev->config.nr_ports = 1;
 	portdev->config.max_nr_ports = 1;
-#if 0 /* Multiport is not quite ready yet --RR */
 	if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT)) {
 		multiport = true;
 		vdev->features[0] |= 1 << VIRTIO_CONSOLE_F_MULTIPORT;
 
-		vdev->config->get(vdev,
-				  offsetof(struct virtio_console_multiport_conf,
-					   nr_ports),
-				  &portdev->config.nr_ports,
-				  sizeof(portdev->config.nr_ports));
-		vdev->config->get(vdev,
-				  offsetof(struct virtio_console_multiport_conf,
-					   max_nr_ports),
+		vdev->config->get(vdev, offsetof(struct virtio_console_config,
+						 max_nr_ports),
 				  &portdev->config.max_nr_ports,
 				  sizeof(portdev->config.max_nr_ports));
-		if (portdev->config.nr_ports > portdev->config.max_nr_ports) {
-			dev_warn(&vdev->dev,
-				 "More ports (%u) specified than allowed (%u). Will init %u ports.",
-				 portdev->config.nr_ports,
-				 portdev->config.max_nr_ports,
-				 portdev->config.max_nr_ports);
-
-			portdev->config.nr_ports = portdev->config.max_nr_ports;
-		}
 	}
 
 	/* Let the Host know we support multiple ports.*/
 	vdev->config->finalize_features(vdev);
-#endif
 
 	err = init_vqs(portdev);
 	if (err < 0) {
···
 
 		spin_lock_init(&portdev->cvq_lock);
 		INIT_WORK(&portdev->control_work, &control_work_handler);
-		INIT_WORK(&portdev->config_work, &config_work_handler);
 
 		nr_added_bufs = fill_queue(portdev->c_ivq, &portdev->cvq_lock);
 		if (!nr_added_bufs) {
···
 			err = -ENOMEM;
 			goto free_vqs;
 		}
+	} else {
+		/*
+		 * For backward compatibility: Create a console port
+		 * if we're running on older host.
+		 */
+		add_port(portdev, 0);
 	}
 
-	for (i = 0; i < portdev->config.nr_ports; i++)
-		add_port(portdev, i);
-
-	/* Start using the new console output. */
-	early_put_chars = NULL;
+	__send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
+			   VIRTIO_CONSOLE_DEVICE_READY, 1);
 	return 0;
 
 free_vqs:
+	/* The host might want to notify mgmt sw about device add failure */
+	__send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
+			   VIRTIO_CONSOLE_DEVICE_READY, 0);
 	vdev->config->del_vqs(vdev);
 	kfree(portdev->in_vqs);
 	kfree(portdev->out_vqs);
···
 	portdev = vdev->priv;
 
 	cancel_work_sync(&portdev->control_work);
-	cancel_work_sync(&portdev->config_work);
 
 	list_for_each_entry_safe(port, port2, &portdev->ports, list)
 		remove_port(port);
 
 	unregister_chrdev(portdev->chr_major, "virtio-portsdev");
 
-	while ((buf = portdev->c_ivq->vq_ops->get_buf(portdev->c_ivq, &len)))
+	while ((buf = virtqueue_get_buf(portdev->c_ivq, &len)))
 		free_buf(buf);
 
-	while ((buf = portdev->c_ivq->vq_ops->detach_unused_buf(portdev->c_ivq)))
+	while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq)))
 		free_buf(buf);
 
 	vdev->config->del_vqs(vdev);
···
 
 static unsigned int features[] = {
 	VIRTIO_CONSOLE_F_SIZE,
+	VIRTIO_CONSOLE_F_MULTIPORT,
 };
 
 static struct virtio_driver virtio_console = {

drivers/net/virtio_net.c

···
 	struct virtnet_info *vi = svq->vdev->priv;
 
 	/* Suppress further interrupts. */
-	svq->vq_ops->disable_cb(svq);
+	virtqueue_disable_cb(svq);
 
 	/* We were probably waiting for more output buffers. */
 	netif_wake_queue(vi->dev);
···
 			return -EINVAL;
 		}
 
-		page = vi->rvq->vq_ops->get_buf(vi->rvq, &len);
+		page = virtqueue_get_buf(vi->rvq, &len);
 		if (!page) {
 			pr_debug("%s: rx error: %d buffers missing\n",
 				 skb->dev->name, hdr->mhdr.num_buffers);
···
 
 	skb_to_sgvec(skb, vi->rx_sg + 1, 0, skb->len);
 
-	err = vi->rvq->vq_ops->add_buf(vi->rvq, vi->rx_sg, 0, 2, skb);
+	err = virtqueue_add_buf(vi->rvq, vi->rx_sg, 0, 2, skb);
 	if (err < 0)
 		dev_kfree_skb(skb);
 
···
 
 	/* chain first in list head */
 	first->private = (unsigned long)list;
-	err = vi->rvq->vq_ops->add_buf(vi->rvq, vi->rx_sg, 0, MAX_SKB_FRAGS + 2,
+	err = virtqueue_add_buf(vi->rvq, vi->rx_sg, 0, MAX_SKB_FRAGS + 2,
 				       first);
 	if (err < 0)
 		give_pages(vi, first);
···
 
 	sg_init_one(vi->rx_sg, page_address(page), PAGE_SIZE);
 
-	err = vi->rvq->vq_ops->add_buf(vi->rvq, vi->rx_sg, 0, 1, page);
+	err = virtqueue_add_buf(vi->rvq, vi->rx_sg, 0, 1, page);
 	if (err < 0)
 		give_pages(vi, page);
 
···
 	} while (err > 0);
 	if (unlikely(vi->num > vi->max))
 		vi->max = vi->num;
-	vi->rvq->vq_ops->kick(vi->rvq);
+	virtqueue_kick(vi->rvq);
 	return !oom;
 }
 
···
 	struct virtnet_info *vi = rvq->vdev->priv;
 	/* Schedule NAPI, Suppress further interrupts if successful. */
 	if (napi_schedule_prep(&vi->napi)) {
-		rvq->vq_ops->disable_cb(rvq);
+		virtqueue_disable_cb(rvq);
 		__napi_schedule(&vi->napi);
 	}
 }
···
 
 again:
 	while (received < budget &&
-	       (buf = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
+	       (buf = virtqueue_get_buf(vi->rvq, &len)) != NULL) {
 		receive_buf(vi->dev, buf, len);
 		--vi->num;
 		received++;
···
 	/* Out of packets? */
 	if (received < budget) {
 		napi_complete(napi);
-		if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq)) &&
+		if (unlikely(!virtqueue_enable_cb(vi->rvq)) &&
 		    napi_schedule_prep(napi)) {
-			vi->rvq->vq_ops->disable_cb(vi->rvq);
+			virtqueue_disable_cb(vi->rvq);
 			__napi_schedule(napi);
 			goto again;
 		}
···
 	struct sk_buff *skb;
 	unsigned int len, tot_sgs = 0;
 
-	while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
+	while ((skb = virtqueue_get_buf(vi->svq, &len)) != NULL) {
 		pr_debug("Sent skb %p\n", skb);
 		vi->dev->stats.tx_bytes += skb->len;
 		vi->dev->stats.tx_packets++;
···
 		sg_set_buf(vi->tx_sg, &hdr->hdr, sizeof hdr->hdr);
 
 	hdr->num_sg = skb_to_sgvec(skb, vi->tx_sg + 1, 0, skb->len) + 1;
-	return vi->svq->vq_ops->add_buf(vi->svq, vi->tx_sg, hdr->num_sg,
+	return virtqueue_add_buf(vi->svq, vi->tx_sg, hdr->num_sg,
 					0, skb);
 }
 
···
 	if (unlikely(capacity < 0)) {
 		netif_stop_queue(dev);
 		dev_warn(&dev->dev, "Unexpected full queue\n");
-		if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
-			vi->svq->vq_ops->disable_cb(vi->svq);
+		if (unlikely(!virtqueue_enable_cb(vi->svq))) {
+			virtqueue_disable_cb(vi->svq);
 			netif_start_queue(dev);
 			goto again;
 		}
 		return NETDEV_TX_BUSY;
 	}
-	vi->svq->vq_ops->kick(vi->svq);
+	virtqueue_kick(vi->svq);
 
 	/* Don't wait up for transmitted skbs to be freed. */
 	skb_orphan(skb);
···
 	 * before it gets out of hand.  Naturally, this wastes entries. */
 	if (capacity < 2+MAX_SKB_FRAGS) {
 		netif_stop_queue(dev);
-		if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
+		if (unlikely(!virtqueue_enable_cb(vi->svq))) {
 			/* More just got used, free them then recheck. */
 			capacity += free_old_xmit_skbs(vi);
 			if (capacity >= 2+MAX_SKB_FRAGS) {
 				netif_start_queue(dev);
-				vi->svq->vq_ops->disable_cb(vi->svq);
+				virtqueue_disable_cb(vi->svq);
 			}
 		}
 	}
···
 	 * now.  virtnet_poll wants re-enable the queue, so we disable here.
 	 * We synchronize against interrupts via NAPI_STATE_SCHED */
 	if (napi_schedule_prep(&vi->napi)) {
-		vi->rvq->vq_ops->disable_cb(vi->rvq);
+		virtqueue_disable_cb(vi->rvq);
 		__napi_schedule(&vi->napi);
 	}
 	return 0;
···
 		sg_set_buf(&sg[i + 1], sg_virt(s), s->length);
 	sg_set_buf(&sg[out + in - 1], &status, sizeof(status));
 
-	BUG_ON(vi->cvq->vq_ops->add_buf(vi->cvq, sg, out, in, vi) < 0);
+	BUG_ON(virtqueue_add_buf(vi->cvq, sg, out, in, vi) < 0);
 
-	vi->cvq->vq_ops->kick(vi->cvq);
+	virtqueue_kick(vi->cvq);
 
 	/*
 	 * Spin for a response, the kick causes an ioport write, trapping
 	 * into the hypervisor, so the request should be handled immediately.
 	 */
-	while (!vi->cvq->vq_ops->get_buf(vi->cvq, &tmp))
+	while (!virtqueue_get_buf(vi->cvq, &tmp))
 		cpu_relax();
 
 	return status == VIRTIO_NET_OK;
···
 {
 	void *buf;
 	while (1) {
-		buf = vi->svq->vq_ops->detach_unused_buf(vi->svq);
+		buf = virtqueue_detach_unused_buf(vi->svq);
 		if (!buf)
 			break;
 		dev_kfree_skb(buf);
 	}
 	while (1) {
-		buf = vi->rvq->vq_ops->detach_unused_buf(vi->rvq);
+		buf = virtqueue_detach_unused_buf(vi->rvq);
 		if (!buf)
 			break;
 		if (vi->mergeable_rx_bufs || vi->big_packets)

drivers/virtio/virtio_balloon.c

···
 	struct virtio_balloon *vb;
 	unsigned int len;
 
-	vb = vq->vq_ops->get_buf(vq, &len);
+	vb = virtqueue_get_buf(vq, &len);
 	if (vb)
 		complete(&vb->acked);
 }
···
 	init_completion(&vb->acked);
 
 	/* We should always be able to add one buffer to an empty queue. */
-	if (vq->vq_ops->add_buf(vq, &sg, 1, 0, vb) < 0)
+	if (virtqueue_add_buf(vq, &sg, 1, 0, vb) < 0)
 		BUG();
-	vq->vq_ops->kick(vq);
+	virtqueue_kick(vq);
 
 	/* When host has read buffer, this completes via balloon_ack */
 	wait_for_completion(&vb->acked);
···
 	struct virtio_balloon *vb;
 	unsigned int len;
 
-	vb = vq->vq_ops->get_buf(vq, &len);
+	vb = virtqueue_get_buf(vq, &len);
 	if (!vb)
 		return;
 	vb->need_stats_update = 1;
···
 
 	vq = vb->stats_vq;
 	sg_init_one(&sg, vb->stats, sizeof(vb->stats));
-	if (vq->vq_ops->add_buf(vq, &sg, 1, 0, vb) < 0)
+	if (virtqueue_add_buf(vq, &sg, 1, 0, vb) < 0)
 		BUG();
-	vq->vq_ops->kick(vq);
+	virtqueue_kick(vq);
 }
 
 static void virtballoon_changed(struct virtio_device *vdev)
···
 		 * use it to signal us later.
 		 */
 		sg_init_one(&sg, vb->stats, sizeof vb->stats);
-		if (vb->stats_vq->vq_ops->add_buf(vb->stats_vq,
-						  &sg, 1, 0, vb) < 0)
+		if (virtqueue_add_buf(vb->stats_vq, &sg, 1, 0, vb) < 0)
 			BUG();
-		vb->stats_vq->vq_ops->kick(vb->stats_vq);
+		virtqueue_kick(vb->stats_vq);
 	}
 
 	vb->thread = kthread_run(balloon, vb, "vballoon");

drivers/virtio/virtio_ring.c

···
 static int vring_add_indirect(struct vring_virtqueue *vq,
 			      struct scatterlist sg[],
 			      unsigned int out,
-			      unsigned int in)
+			      unsigned int in,
+			      gfp_t gfp)
 {
 	struct vring_desc *desc;
 	unsigned head;
 	int i;
 
-	desc = kmalloc((out + in) * sizeof(struct vring_desc), GFP_ATOMIC);
+	desc = kmalloc((out + in) * sizeof(struct vring_desc), gfp);
 	if (!desc)
 		return vq->vring.num;
 
···
 	return head;
 }
 
-static int vring_add_buf(struct virtqueue *_vq,
-			 struct scatterlist sg[],
-			 unsigned int out,
-			 unsigned int in,
-			 void *data)
+int virtqueue_add_buf_gfp(struct virtqueue *_vq,
+			  struct scatterlist sg[],
+			  unsigned int out,
+			  unsigned int in,
+			  void *data,
+			  gfp_t gfp)
 {
 	struct vring_virtqueue *vq = to_vvq(_vq);
 	unsigned int i, avail, head, uninitialized_var(prev);
···
 	/* If the host supports indirect descriptor tables, and we have multiple
 	 * buffers, then go indirect. FIXME: tune this threshold */
 	if (vq->indirect && (out + in) > 1 && vq->num_free) {
-		head = vring_add_indirect(vq, sg, out, in);
+		head = vring_add_indirect(vq, sg, out, in, gfp);
 		if (head != vq->vring.num)
 			goto add_head;
 	}
···
 		return vq->num_free ? vq->vring.num : 0;
 	return vq->num_free;
 }
+EXPORT_SYMBOL_GPL(virtqueue_add_buf_gfp);
 
-static void vring_kick(struct virtqueue *_vq)
+void virtqueue_kick(struct virtqueue *_vq)
 {
 	struct vring_virtqueue *vq = to_vvq(_vq);
 	START_USE(vq);
···
 
 	END_USE(vq);
 }
+EXPORT_SYMBOL_GPL(virtqueue_kick);
 
 static void detach_buf(struct vring_virtqueue *vq, unsigned int head)
 {
···
 	return vq->last_used_idx != vq->vring.used->idx;
 }
 
-static void *vring_get_buf(struct virtqueue *_vq, unsigned int *len)
+void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len)
 {
 	struct vring_virtqueue *vq = to_vvq(_vq);
 	void *ret;
···
 	END_USE(vq);
 	return ret;
 }
+EXPORT_SYMBOL_GPL(virtqueue_get_buf);
 
-static void vring_disable_cb(struct virtqueue *_vq)
+void virtqueue_disable_cb(struct virtqueue *_vq)
 {
 	struct vring_virtqueue *vq = to_vvq(_vq);
 
 	vq->vring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
 }
+EXPORT_SYMBOL_GPL(virtqueue_disable_cb);
 
-static bool vring_enable_cb(struct virtqueue *_vq)
+bool virtqueue_enable_cb(struct virtqueue *_vq)
 {
 	struct vring_virtqueue *vq = to_vvq(_vq);
 
···
 	END_USE(vq);
 	return true;
 }
+EXPORT_SYMBOL_GPL(virtqueue_enable_cb);
 
-static void *vring_detach_unused_buf(struct virtqueue *_vq)
+void *virtqueue_detach_unused_buf(struct virtqueue *_vq)
 {
 	struct vring_virtqueue *vq = to_vvq(_vq);
 	unsigned int i;
···
 	END_USE(vq);
 	return NULL;
 }
+EXPORT_SYMBOL_GPL(virtqueue_detach_unused_buf);
 
 irqreturn_t vring_interrupt(int irq, void *_vq)
 {
···
 	return IRQ_HANDLED;
 }
 EXPORT_SYMBOL_GPL(vring_interrupt);
-
-static struct virtqueue_ops vring_vq_ops = {
-	.add_buf = vring_add_buf,
-	.get_buf = vring_get_buf,
-	.kick = vring_kick,
-	.disable_cb = vring_disable_cb,
-	.enable_cb = vring_enable_cb,
-	.detach_unused_buf = vring_detach_unused_buf,
-};
 
 struct virtqueue *vring_new_virtqueue(unsigned int num,
 				      unsigned int vring_align,
···
 	vring_init(&vq->vring, num, pages, vring_align);
 	vq->vq.callback = callback;
 	vq->vq.vdev = vdev;
-	vq->vq.vq_ops = &vring_vq_ops;
 	vq->vq.name = name;
 	vq->notify = notify;
 	vq->broken = false;

include/linux/virtio.h

···
 #include <linux/spinlock.h>
 #include <linux/device.h>
 #include <linux/mod_devicetable.h>
+#include <linux/gfp.h>
 
 /**
  * virtqueue - a queue to register buffers for sending or receiving.
···
  * @callback: the function to call when buffers are consumed (can be NULL).
  * @name: the name of this virtqueue (mainly for debugging)
  * @vdev: the virtio device this queue was created for.
- * @vq_ops: the operations for this virtqueue (see below).
  * @priv: a pointer for the virtqueue implementation to use.
  */
 struct virtqueue {
···
 	void (*callback)(struct virtqueue *vq);
 	const char *name;
 	struct virtio_device *vdev;
-	struct virtqueue_ops *vq_ops;
 	void *priv;
 };
 
 /**
- * virtqueue_ops - operations for virtqueue abstraction layer
- * @add_buf: expose buffer to other end
+ * operations for virtqueue
+ * virtqueue_add_buf: expose buffer to other end
  *	vq: the struct virtqueue we're talking about.
  *	sg: the description of the buffer(s).
  *	out_num: the number of sg readable by other side
  *	in_num: the number of sg which are writable (after readable ones)
  *	data: the token identifying the buffer.
+ *	gfp: how to do memory allocations (if necessary).
  *      Returns remaining capacity of queue (sg segments) or a negative error.
- * @kick: update after add_buf
+ * virtqueue_kick: update after add_buf
  *	vq: the struct virtqueue
  *	After one or more add_buf calls, invoke this to kick the other side.
- * @get_buf: get the next used buffer
+ * virtqueue_get_buf: get the next used buffer
  *	vq: the struct virtqueue we're talking about.
  *	len: the length written into the buffer
  *	Returns NULL or the "data" token handed to add_buf.
- * @disable_cb: disable callbacks
+ * virtqueue_disable_cb: disable callbacks
  *	vq: the struct virtqueue we're talking about.
  *	Note that this is not necessarily synchronous, hence unreliable and only
  *	useful as an optimization.
- * @enable_cb: restart callbacks after disable_cb.
+ * virtqueue_enable_cb: restart callbacks after disable_cb.
  *	vq: the struct virtqueue we're talking about.
  *	This re-enables callbacks; it returns "false" if there are pending
  *	buffers in the queue, to detect a possible race between the driver
  *	checking for more work, and enabling callbacks.
- * @detach_unused_buf: detach first unused buffer
+ * virtqueue_detach_unused_buf: detach first unused buffer
  * 	vq: the struct virtqueue we're talking about.
  * 	Returns NULL or the "data" token handed to add_buf
  *
  * Locking rules are straightforward: the driver is responsible for
  * locking.  No two operations may be invoked simultaneously, with the exception
- * of @disable_cb.
+ * of virtqueue_disable_cb.
  *
  * All operations can be called in any context.
  */
-struct virtqueue_ops {
-	int (*add_buf)(struct virtqueue *vq,
-		       struct scatterlist sg[],
-		       unsigned int out_num,
-		       unsigned int in_num,
-		       void *data);
 
-	void (*kick)(struct virtqueue *vq);
+int virtqueue_add_buf_gfp(struct virtqueue *vq,
+			  struct scatterlist sg[],
+			  unsigned int out_num,
+			  unsigned int in_num,
+			  void *data,
+			  gfp_t gfp);
 
-	void *(*get_buf)(struct virtqueue *vq, unsigned int *len);
+static inline int virtqueue_add_buf(struct virtqueue *vq,
+				    struct scatterlist sg[],
+				    unsigned int out_num,
+				    unsigned int in_num,
+				    void *data)
+{
+	return virtqueue_add_buf_gfp(vq, sg, out_num, in_num, data, GFP_ATOMIC);
+}
 
-	void (*disable_cb)(struct virtqueue *vq);
-	bool (*enable_cb)(struct virtqueue *vq);
-	void *(*detach_unused_buf)(struct virtqueue *vq);
-};
+void virtqueue_kick(struct virtqueue *vq);
+
+void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);
+
+void virtqueue_disable_cb(struct virtqueue *vq);
+
+bool virtqueue_enable_cb(struct virtqueue *vq);
+
+void *virtqueue_detach_unused_buf(struct virtqueue *vq);
 
 /**
  * virtio_device - representation of a device using virtio

include/linux/virtio_blk.h

···
 #define VIRTIO_BLK_F_FLUSH	9	/* Cache flush command support */
 #define VIRTIO_BLK_F_TOPOLOGY	10	/* Topology information is available */
 
+#define VIRTIO_BLK_ID_BYTES	20	/* ID string length */
+
 struct virtio_blk_config {
 	/* The capacity (in 512-byte sectors). */
 	__u64 capacity;
···
 
 /* Cache flush command */
 #define VIRTIO_BLK_T_FLUSH	4
+
+/* Get device ID command */
+#define VIRTIO_BLK_T_GET_ID    8
 
 /* Barrier before this op. */
 #define VIRTIO_BLK_T_BARRIER	0x80000000

include/linux/virtio_console.h

···
 
 /* Feature bits */
 #define VIRTIO_CONSOLE_F_SIZE	0	/* Does host provide console size? */
+#define VIRTIO_CONSOLE_F_MULTIPORT 1	/* Does host provide multiple ports? */
+
+#define VIRTIO_CONSOLE_BAD_ID		(~(u32)0)
 
 struct virtio_console_config {
 	/* colums of the screens */
 	__u16 cols;
 	/* rows of the screens */
 	__u16 rows;
+	/* max. number of ports this device can hold */
+	__u32 max_nr_ports;
 } __attribute__((packed));
+
+/*
+ * A message that's passed between the Host and the Guest for a
+ * particular port.
+ */
+struct virtio_console_control {
+	__u32 id;		/* Port number */
+	__u16 event;		/* The kind of control event (see below) */
+	__u16 value;		/* Extra information for the key */
+};
+
+/* Some events for control messages */
+#define VIRTIO_CONSOLE_DEVICE_READY	0
+#define VIRTIO_CONSOLE_PORT_ADD		1
+#define VIRTIO_CONSOLE_PORT_REMOVE	2
+#define VIRTIO_CONSOLE_PORT_READY	3
+#define VIRTIO_CONSOLE_CONSOLE_PORT	4
+#define VIRTIO_CONSOLE_RESIZE		5
+#define VIRTIO_CONSOLE_PORT_OPEN	6
+#define VIRTIO_CONSOLE_PORT_NAME	7
 
 #ifdef __KERNEL__
 int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int));

net/9p/trans_virtio.c

···
 
 	P9_DPRINTK(P9_DEBUG_TRANS, ": request done\n");
 
-	while ((rc = chan->vq->vq_ops->get_buf(chan->vq, &len)) != NULL) {
+	while ((rc = virtqueue_get_buf(chan->vq, &len)) != NULL) {
 		P9_DPRINTK(P9_DEBUG_TRANS, ": rc %p\n", rc);
 		P9_DPRINTK(P9_DEBUG_TRANS, ": lookup tag %d\n", rc->tag);
 		req = p9_tag_lookup(chan->client, rc->tag);
···
 
 	req->status = REQ_STATUS_SENT;
 
-	if (chan->vq->vq_ops->add_buf(chan->vq, chan->sg, out, in, req->tc) < 0) {
+	if (virtqueue_add_buf(chan->vq, chan->sg, out, in, req->tc) < 0) {
 		P9_DPRINTK(P9_DEBUG_TRANS,
 			"9p debug: virtio rpc add_buf returned failure");
 		return -EIO;
 	}
 
-	chan->vq->vq_ops->kick(chan->vq);
+	virtqueue_kick(chan->vq);
 
 	P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request kicked\n");
 	return 0;