2 * Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation
3 * Copyright (C) 2009, 2010, 2011 Red Hat, Inc.
4 * Copyright (C) 2009, 2010, 2011 Amit Shah <amit.shah@redhat.com>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 #include <linux/cdev.h>
21 #include <linux/debugfs.h>
22 #include <linux/completion.h>
23 #include <linux/device.h>
24 #include <linux/err.h>
25 #include <linux/freezer.h>
27 #include <linux/init.h>
28 #include <linux/list.h>
29 #include <linux/poll.h>
30 #include <linux/sched.h>
31 #include <linux/slab.h>
32 #include <linux/spinlock.h>
33 #include <linux/virtio.h>
34 #include <linux/virtio_console.h>
35 #include <linux/wait.h>
36 #include <linux/workqueue.h>
37 #include "../tty/hvc/hvc_console.h"
40 * This is a global struct for storing common data for all the devices
41 * this driver handles.
43 * Mainly, it has a linked list for all the consoles in one place so
44 * that callbacks from hvc for get_chars(), put_chars() work properly
45 * across multiple devices and multiple ports per device.
47 struct ports_driver_data
{
48 /* Used for registering chardevs */
51 /* Used for exporting per-port information to debugfs */
52 struct dentry
*debugfs_dir
;
54 /* List of all the devices we're handling */
55 struct list_head portdevs
;
57 /* Number of devices this driver is handling */
61 * This is used to keep track of the number of hvc consoles
62 * spawned by this driver. This number is given as the first
63 * argument to hvc_alloc(). To correctly map an initial
64 * console spawned via hvc_instantiate to the console being
65 * hooked up via hvc_alloc, we need to pass the same vtermno.
67 * We also just assume the first console being initialised was
68 * the first one that got used as the initial console.
70 unsigned int next_vtermno
;
72 /* All the console devices handled by this driver */
73 struct list_head consoles
;
75 static struct ports_driver_data pdrvdata
;
77 DEFINE_SPINLOCK(pdrvdata_lock
);
78 DECLARE_COMPLETION(early_console_added
);
80 /* This struct holds information that's relevant only for console ports */
82 /* We'll place all consoles in a list in the pdrvdata struct */
83 struct list_head list
;
85 /* The hvc device associated with this console port */
86 struct hvc_struct
*hvc
;
88 /* The size of the console */
92 * This number identifies the number that we used to register
93 * with hvc in hvc_instantiate() and hvc_alloc(); this is the
94 * number passed on by the hvc callbacks to us to
95 * differentiate between the other console ports handled by
104 /* size of the buffer in *buf above */
107 /* used length of the buffer */
109 /* offset in the buf from which to consume data */
114 * This is a per-device struct that stores data common to all the
115 * ports for that device (vdev->priv).
117 struct ports_device
{
118 /* Next portdev in the list, head is in the pdrvdata struct */
119 struct list_head list
;
122 * Workqueue handlers where we process deferred work after
125 struct work_struct control_work
;
127 struct list_head ports
;
129 /* To protect the list of ports */
130 spinlock_t ports_lock
;
132 /* To protect the vq operations for the control channel */
135 /* The current config space is stored here */
136 struct virtio_console_config config
;
138 /* The virtio device we're associated with */
139 struct virtio_device
*vdev
;
142 * A couple of virtqueues for the control channel: one for
143 * guest->host transfers, one for host->guest transfers
145 struct virtqueue
*c_ivq
, *c_ovq
;
147 /* Array of per-port IO virtqueues */
148 struct virtqueue
**in_vqs
, **out_vqs
;
150 /* Used for numbering devices for sysfs and debugfs */
151 unsigned int drv_index
;
153 /* Major number for this device. Ports will be created as minors. */
158 unsigned long bytes_sent
, bytes_received
, bytes_discarded
;
161 /* This struct holds the per-port data */
163 /* Next port in the list, head is in the ports_device */
164 struct list_head list
;
166 /* Pointer to the parent virtio_console device */
167 struct ports_device
*portdev
;
169 /* The current buffer from which data has to be fed to readers */
170 struct port_buffer
*inbuf
;
173 * To protect the operations on the in_vq associated with this
174 * port. Has to be a spinlock because it can be called from
175 * interrupt context (get_char()).
177 spinlock_t inbuf_lock
;
179 /* Protect the operations on the out_vq. */
180 spinlock_t outvq_lock
;
182 /* The IO vqs for this port */
183 struct virtqueue
*in_vq
, *out_vq
;
185 /* File in the debugfs directory that exposes this port's information */
186 struct dentry
*debugfs_file
;
189 * Keep count of the bytes sent, received and discarded for
190 * this port for accounting and debugging purposes. These
191 * counts are not reset across port open / close events.
193 struct port_stats stats
;
196 * The entries in this struct will be valid if this port is
197 * hooked up to an hvc console
201 /* Each port associates with a separate char device */
205 /* Reference-counting to handle port hot-unplugs and file operations */
208 /* A waitqueue for poll() or blocking read operations */
209 wait_queue_head_t waitqueue
;
211 /* The 'name' of the port that we expose via sysfs properties */
214 /* We can notify apps of host connect / disconnect events via SIGIO */
215 struct fasync_struct
*async_queue
;
217 /* The 'id' to identify the port with the Host */
222 /* Is the host device open */
225 /* We should allow only one process to open a port */
226 bool guest_connected
;
229 /* This is the very early arch-specified put chars function. */
230 static int (*early_put_chars
)(u32
, const char *, int);
232 static struct port
*find_port_by_vtermno(u32 vtermno
)
235 struct console
*cons
;
238 spin_lock_irqsave(&pdrvdata_lock
, flags
);
239 list_for_each_entry(cons
, &pdrvdata
.consoles
, list
) {
240 if (cons
->vtermno
== vtermno
) {
241 port
= container_of(cons
, struct port
, cons
);
247 spin_unlock_irqrestore(&pdrvdata_lock
, flags
);
251 static struct port
*find_port_by_devt_in_portdev(struct ports_device
*portdev
,
257 spin_lock_irqsave(&portdev
->ports_lock
, flags
);
258 list_for_each_entry(port
, &portdev
->ports
, list
)
259 if (port
->cdev
->dev
== dev
)
263 spin_unlock_irqrestore(&portdev
->ports_lock
, flags
);
268 static struct port
*find_port_by_devt(dev_t dev
)
270 struct ports_device
*portdev
;
274 spin_lock_irqsave(&pdrvdata_lock
, flags
);
275 list_for_each_entry(portdev
, &pdrvdata
.portdevs
, list
) {
276 port
= find_port_by_devt_in_portdev(portdev
, dev
);
282 spin_unlock_irqrestore(&pdrvdata_lock
, flags
);
286 static struct port
*find_port_by_id(struct ports_device
*portdev
, u32 id
)
291 spin_lock_irqsave(&portdev
->ports_lock
, flags
);
292 list_for_each_entry(port
, &portdev
->ports
, list
)
297 spin_unlock_irqrestore(&portdev
->ports_lock
, flags
);
302 static struct port
*find_port_by_vq(struct ports_device
*portdev
,
303 struct virtqueue
*vq
)
308 spin_lock_irqsave(&portdev
->ports_lock
, flags
);
309 list_for_each_entry(port
, &portdev
->ports
, list
)
310 if (port
->in_vq
== vq
|| port
->out_vq
== vq
)
314 spin_unlock_irqrestore(&portdev
->ports_lock
, flags
);
318 static bool is_console_port(struct port
*port
)
325 static inline bool use_multiport(struct ports_device
*portdev
)
328 * This condition can be true when put_chars is called from
333 return portdev
->vdev
->features
[0] & (1 << VIRTIO_CONSOLE_F_MULTIPORT
);
336 static void free_buf(struct port_buffer
*buf
)
342 static struct port_buffer
*alloc_buf(size_t buf_size
)
344 struct port_buffer
*buf
;
346 buf
= kmalloc(sizeof(*buf
), GFP_KERNEL
);
349 buf
->buf
= kzalloc(buf_size
, GFP_KERNEL
);
354 buf
->size
= buf_size
;
363 /* Callers should take appropriate locks */
364 static struct port_buffer
*get_inbuf(struct port
*port
)
366 struct port_buffer
*buf
;
372 buf
= virtqueue_get_buf(port
->in_vq
, &len
);
376 port
->stats
.bytes_received
+= len
;
382 * Create a scatter-gather list representing our input buffer and put
385 * Callers should take appropriate locks.
387 static int add_inbuf(struct virtqueue
*vq
, struct port_buffer
*buf
)
389 struct scatterlist sg
[1];
392 sg_init_one(sg
, buf
->buf
, buf
->size
);
394 ret
= virtqueue_add_buf(vq
, sg
, 0, 1, buf
);
399 /* Discard any unread data this port has. Callers lockers. */
400 static void discard_port_data(struct port
*port
)
402 struct port_buffer
*buf
;
405 if (!port
->portdev
) {
406 /* Device has been unplugged. vqs are already gone. */
409 buf
= get_inbuf(port
);
413 port
->stats
.bytes_discarded
+= buf
->len
- buf
->offset
;
414 if (add_inbuf(port
->in_vq
, buf
) < 0) {
419 buf
= get_inbuf(port
);
422 dev_warn(port
->dev
, "Errors adding %d buffers back to vq\n",
426 static bool port_has_data(struct port
*port
)
432 spin_lock_irqsave(&port
->inbuf_lock
, flags
);
433 port
->inbuf
= get_inbuf(port
);
437 spin_unlock_irqrestore(&port
->inbuf_lock
, flags
);
441 static ssize_t
__send_control_msg(struct ports_device
*portdev
, u32 port_id
,
442 unsigned int event
, unsigned int value
)
444 struct scatterlist sg
[1];
445 struct virtio_console_control cpkt
;
446 struct virtqueue
*vq
;
449 if (!use_multiport(portdev
))
458 sg_init_one(sg
, &cpkt
, sizeof(cpkt
));
459 if (virtqueue_add_buf(vq
, sg
, 1, 0, &cpkt
) >= 0) {
461 while (!virtqueue_get_buf(vq
, &len
))
467 static ssize_t
send_control_msg(struct port
*port
, unsigned int event
,
470 /* Did the port get unplugged before userspace closed it? */
472 return __send_control_msg(port
->portdev
, port
->id
, event
, value
);
476 /* Callers must take the port->outvq_lock */
477 static void reclaim_consumed_buffers(struct port
*port
)
482 if (!port
->portdev
) {
483 /* Device has been unplugged. vqs are already gone. */
486 while ((buf
= virtqueue_get_buf(port
->out_vq
, &len
))) {
488 port
->outvq_full
= false;
492 static ssize_t
send_buf(struct port
*port
, void *in_buf
, size_t in_count
,
495 struct scatterlist sg
[1];
496 struct virtqueue
*out_vq
;
501 out_vq
= port
->out_vq
;
503 spin_lock_irqsave(&port
->outvq_lock
, flags
);
505 reclaim_consumed_buffers(port
);
507 sg_init_one(sg
, in_buf
, in_count
);
508 ret
= virtqueue_add_buf(out_vq
, sg
, 1, 0, in_buf
);
510 /* Tell Host to go! */
511 virtqueue_kick(out_vq
);
519 port
->outvq_full
= true;
525 * Wait till the host acknowledges it pushed out the data we
526 * sent. This is done for data from the hvc_console; the tty
527 * operations are performed with spinlocks held so we can't
528 * sleep here. An alternative would be to copy the data to a
529 * buffer and relax the spinning requirement. The downside is
530 * we need to kmalloc a GFP_ATOMIC buffer each time the
531 * console driver writes something out.
533 while (!virtqueue_get_buf(out_vq
, &len
))
536 spin_unlock_irqrestore(&port
->outvq_lock
, flags
);
538 port
->stats
.bytes_sent
+= in_count
;
540 * We're expected to return the amount of data we wrote -- all
547 * Give out the data that's requested from the buffer that we have
550 static ssize_t
fill_readbuf(struct port
*port
, char *out_buf
, size_t out_count
,
553 struct port_buffer
*buf
;
556 if (!out_count
|| !port_has_data(port
))
560 out_count
= min(out_count
, buf
->len
- buf
->offset
);
565 ret
= copy_to_user(out_buf
, buf
->buf
+ buf
->offset
, out_count
);
569 memcpy(out_buf
, buf
->buf
+ buf
->offset
, out_count
);
572 buf
->offset
+= out_count
;
574 if (buf
->offset
== buf
->len
) {
576 * We're done using all the data in this buffer.
577 * Re-queue so that the Host can send us more data.
579 spin_lock_irqsave(&port
->inbuf_lock
, flags
);
582 if (add_inbuf(port
->in_vq
, buf
) < 0)
583 dev_warn(port
->dev
, "failed add_buf\n");
585 spin_unlock_irqrestore(&port
->inbuf_lock
, flags
);
587 /* Return the number of bytes actually copied */
591 /* The condition that must be true for polling to end */
592 static bool will_read_block(struct port
*port
)
594 if (!port
->guest_connected
) {
595 /* Port got hot-unplugged. Let's exit. */
598 return !port_has_data(port
) && port
->host_connected
;
601 static bool will_write_block(struct port
*port
)
605 if (!port
->guest_connected
) {
606 /* Port got hot-unplugged. Let's exit. */
609 if (!port
->host_connected
)
612 spin_lock_irq(&port
->outvq_lock
);
614 * Check if the Host has consumed any buffers since we last
615 * sent data (this is only applicable for nonblocking ports).
617 reclaim_consumed_buffers(port
);
618 ret
= port
->outvq_full
;
619 spin_unlock_irq(&port
->outvq_lock
);
624 static ssize_t
port_fops_read(struct file
*filp
, char __user
*ubuf
,
625 size_t count
, loff_t
*offp
)
630 port
= filp
->private_data
;
632 if (!port_has_data(port
)) {
634 * If nothing's connected on the host just return 0 in
635 * case of list_empty; this tells the userspace app
636 * that there's no connection
638 if (!port
->host_connected
)
640 if (filp
->f_flags
& O_NONBLOCK
)
643 ret
= wait_event_freezable(port
->waitqueue
,
644 !will_read_block(port
));
648 /* Port got hot-unplugged. */
649 if (!port
->guest_connected
)
652 * We could've received a disconnection message while we were
653 * waiting for more data.
655 * This check is not clubbed in the if() statement above as we
656 * might receive some data as well as the host could get
657 * disconnected after we got woken up from our wait. So we
658 * really want to give off whatever data we have and only then
659 * check for host_connected.
661 if (!port_has_data(port
) && !port
->host_connected
)
664 return fill_readbuf(port
, ubuf
, count
, true);
667 static ssize_t
port_fops_write(struct file
*filp
, const char __user
*ubuf
,
668 size_t count
, loff_t
*offp
)
675 /* Userspace could be out to fool us */
679 port
= filp
->private_data
;
681 nonblock
= filp
->f_flags
& O_NONBLOCK
;
683 if (will_write_block(port
)) {
687 ret
= wait_event_freezable(port
->waitqueue
,
688 !will_write_block(port
));
692 /* Port got hot-unplugged. */
693 if (!port
->guest_connected
)
696 count
= min((size_t)(32 * 1024), count
);
698 buf
= kmalloc(count
, GFP_KERNEL
);
702 ret
= copy_from_user(buf
, ubuf
, count
);
709 * We now ask send_buf() to not spin for generic ports -- we
710 * can re-use the same code path that non-blocking file
711 * descriptors take for blocking file descriptors since the
712 * wait is already done and we're certain the write will go
713 * through to the host.
716 ret
= send_buf(port
, buf
, count
, nonblock
);
718 if (nonblock
&& ret
> 0)
727 static unsigned int port_fops_poll(struct file
*filp
, poll_table
*wait
)
732 port
= filp
->private_data
;
733 poll_wait(filp
, &port
->waitqueue
, wait
);
735 if (!port
->guest_connected
) {
736 /* Port got unplugged */
740 if (!will_read_block(port
))
741 ret
|= POLLIN
| POLLRDNORM
;
742 if (!will_write_block(port
))
744 if (!port
->host_connected
)
750 static void remove_port(struct kref
*kref
);
752 static int port_fops_release(struct inode
*inode
, struct file
*filp
)
756 port
= filp
->private_data
;
758 /* Notify host of port being closed */
759 send_control_msg(port
, VIRTIO_CONSOLE_PORT_OPEN
, 0);
761 spin_lock_irq(&port
->inbuf_lock
);
762 port
->guest_connected
= false;
764 discard_port_data(port
);
766 spin_unlock_irq(&port
->inbuf_lock
);
768 spin_lock_irq(&port
->outvq_lock
);
769 reclaim_consumed_buffers(port
);
770 spin_unlock_irq(&port
->outvq_lock
);
773 * Locks aren't necessary here as a port can't be opened after
774 * unplug, and if a port isn't unplugged, a kref would already
775 * exist for the port. Plus, taking ports_lock here would
776 * create a dependency on other locks taken by functions
777 * inside remove_port if we're the last holder of the port,
778 * creating many problems.
780 kref_put(&port
->kref
, remove_port
);
785 static int port_fops_open(struct inode
*inode
, struct file
*filp
)
787 struct cdev
*cdev
= inode
->i_cdev
;
791 port
= find_port_by_devt(cdev
->dev
);
792 filp
->private_data
= port
;
794 /* Prevent against a port getting hot-unplugged at the same time */
795 spin_lock_irq(&port
->portdev
->ports_lock
);
796 kref_get(&port
->kref
);
797 spin_unlock_irq(&port
->portdev
->ports_lock
);
800 * Don't allow opening of console port devices -- that's done
803 if (is_console_port(port
)) {
808 /* Allow only one process to open a particular port at a time */
809 spin_lock_irq(&port
->inbuf_lock
);
810 if (port
->guest_connected
) {
811 spin_unlock_irq(&port
->inbuf_lock
);
816 port
->guest_connected
= true;
817 spin_unlock_irq(&port
->inbuf_lock
);
819 spin_lock_irq(&port
->outvq_lock
);
821 * There might be a chance that we missed reclaiming a few
822 * buffers in the window of the port getting previously closed
825 reclaim_consumed_buffers(port
);
826 spin_unlock_irq(&port
->outvq_lock
);
828 nonseekable_open(inode
, filp
);
830 /* Notify host of port being opened */
831 send_control_msg(filp
->private_data
, VIRTIO_CONSOLE_PORT_OPEN
, 1);
835 kref_put(&port
->kref
, remove_port
);
839 static int port_fops_fasync(int fd
, struct file
*filp
, int mode
)
843 port
= filp
->private_data
;
844 return fasync_helper(fd
, filp
, mode
, &port
->async_queue
);
848 * The file operations that we support: programs in the guest can open
849 * a console device, read from it, write to it, poll for data and
850 * close it. The devices are at
851 * /dev/vport<device number>p<port number>
853 static const struct file_operations port_fops
= {
854 .owner
= THIS_MODULE
,
855 .open
= port_fops_open
,
856 .read
= port_fops_read
,
857 .write
= port_fops_write
,
858 .poll
= port_fops_poll
,
859 .release
= port_fops_release
,
860 .fasync
= port_fops_fasync
,
865 * The put_chars() callback is pretty straightforward.
867 * We turn the characters into a scatter-gather list, add it to the
868 * output queue and then kick the Host. Then we sit here waiting for
869 * it to finish: inefficient in theory, but in practice
870 * implementations will do it immediately (lguest's Launcher does).
872 static int put_chars(u32 vtermno
, const char *buf
, int count
)
876 if (unlikely(early_put_chars
))
877 return early_put_chars(vtermno
, buf
, count
);
879 port
= find_port_by_vtermno(vtermno
);
883 return send_buf(port
, (void *)buf
, count
, false);
887 * get_chars() is the callback from the hvc_console infrastructure
888 * when an interrupt is received.
890 * We call out to fill_readbuf that gets us the required data from the
891 * buffers that are queued up.
893 static int get_chars(u32 vtermno
, char *buf
, int count
)
897 /* If we've not set up the port yet, we have no input to give. */
898 if (unlikely(early_put_chars
))
901 port
= find_port_by_vtermno(vtermno
);
905 /* If we don't have an input queue yet, we can't get input. */
906 BUG_ON(!port
->in_vq
);
908 return fill_readbuf(port
, buf
, count
, false);
911 static void resize_console(struct port
*port
)
913 struct virtio_device
*vdev
;
915 /* The port could have been hot-unplugged */
916 if (!port
|| !is_console_port(port
))
919 vdev
= port
->portdev
->vdev
;
920 if (virtio_has_feature(vdev
, VIRTIO_CONSOLE_F_SIZE
))
921 hvc_resize(port
->cons
.hvc
, port
->cons
.ws
);
924 /* We set the configuration at this point, since we now have a tty */
925 static int notifier_add_vio(struct hvc_struct
*hp
, int data
)
929 port
= find_port_by_vtermno(hp
->vtermno
);
933 hp
->irq_requested
= 1;
934 resize_console(port
);
939 static void notifier_del_vio(struct hvc_struct
*hp
, int data
)
941 hp
->irq_requested
= 0;
944 /* The operations for console ports. */
945 static const struct hv_ops hv_ops
= {
946 .get_chars
= get_chars
,
947 .put_chars
= put_chars
,
948 .notifier_add
= notifier_add_vio
,
949 .notifier_del
= notifier_del_vio
,
950 .notifier_hangup
= notifier_del_vio
,
954 * Console drivers are initialized very early so boot messages can go
955 * out, so we do things slightly differently from the generic virtio
956 * initialization of the net and block drivers.
958 * At this stage, the console is output-only. It's too early to set
959 * up a virtqueue, so we let the drivers do some boutique early-output
962 int __init
virtio_cons_early_init(int (*put_chars
)(u32
, const char *, int))
964 early_put_chars
= put_chars
;
965 return hvc_instantiate(0, 0, &hv_ops
);
968 int init_port_console(struct port
*port
)
973 * The Host's telling us this port is a console port. Hook it
974 * up with an hvc console.
976 * To set up and manage our virtual console, we call
979 * The first argument of hvc_alloc() is the virtual console
980 * number. The second argument is the parameter for the
981 * notification mechanism (like irq number). We currently
982 * leave this as zero, virtqueues have implicit notifications.
984 * The third argument is a "struct hv_ops" containing the
985 * put_chars() get_chars(), notifier_add() and notifier_del()
986 * pointers. The final argument is the output buffer size: we
987 * can do any size, so we put PAGE_SIZE here.
989 port
->cons
.vtermno
= pdrvdata
.next_vtermno
;
991 port
->cons
.hvc
= hvc_alloc(port
->cons
.vtermno
, 0, &hv_ops
, PAGE_SIZE
);
992 if (IS_ERR(port
->cons
.hvc
)) {
993 ret
= PTR_ERR(port
->cons
.hvc
);
995 "error %d allocating hvc for port\n", ret
);
996 port
->cons
.hvc
= NULL
;
999 spin_lock_irq(&pdrvdata_lock
);
1000 pdrvdata
.next_vtermno
++;
1001 list_add_tail(&port
->cons
.list
, &pdrvdata
.consoles
);
1002 spin_unlock_irq(&pdrvdata_lock
);
1003 port
->guest_connected
= true;
1006 * Start using the new console output if this is the first
1007 * console to come up.
1009 if (early_put_chars
)
1010 early_put_chars
= NULL
;
1012 /* Notify host of port being opened */
1013 send_control_msg(port
, VIRTIO_CONSOLE_PORT_OPEN
, 1);
1018 static ssize_t
show_port_name(struct device
*dev
,
1019 struct device_attribute
*attr
, char *buffer
)
1023 port
= dev_get_drvdata(dev
);
1025 return sprintf(buffer
, "%s\n", port
->name
);
1028 static DEVICE_ATTR(name
, S_IRUGO
, show_port_name
, NULL
);
1030 static struct attribute
*port_sysfs_entries
[] = {
1031 &dev_attr_name
.attr
,
1035 static struct attribute_group port_attribute_group
= {
1036 .name
= NULL
, /* put in device directory */
1037 .attrs
= port_sysfs_entries
,
1040 static int debugfs_open(struct inode
*inode
, struct file
*filp
)
1042 filp
->private_data
= inode
->i_private
;
1046 static ssize_t
debugfs_read(struct file
*filp
, char __user
*ubuf
,
1047 size_t count
, loff_t
*offp
)
1051 ssize_t ret
, out_offset
, out_count
;
1054 buf
= kmalloc(out_count
, GFP_KERNEL
);
1058 port
= filp
->private_data
;
1060 out_offset
+= snprintf(buf
+ out_offset
, out_count
,
1061 "name: %s\n", port
->name
? port
->name
: "");
1062 out_offset
+= snprintf(buf
+ out_offset
, out_count
- out_offset
,
1063 "guest_connected: %d\n", port
->guest_connected
);
1064 out_offset
+= snprintf(buf
+ out_offset
, out_count
- out_offset
,
1065 "host_connected: %d\n", port
->host_connected
);
1066 out_offset
+= snprintf(buf
+ out_offset
, out_count
- out_offset
,
1067 "outvq_full: %d\n", port
->outvq_full
);
1068 out_offset
+= snprintf(buf
+ out_offset
, out_count
- out_offset
,
1069 "bytes_sent: %lu\n", port
->stats
.bytes_sent
);
1070 out_offset
+= snprintf(buf
+ out_offset
, out_count
- out_offset
,
1071 "bytes_received: %lu\n",
1072 port
->stats
.bytes_received
);
1073 out_offset
+= snprintf(buf
+ out_offset
, out_count
- out_offset
,
1074 "bytes_discarded: %lu\n",
1075 port
->stats
.bytes_discarded
);
1076 out_offset
+= snprintf(buf
+ out_offset
, out_count
- out_offset
,
1078 is_console_port(port
) ? "yes" : "no");
1079 out_offset
+= snprintf(buf
+ out_offset
, out_count
- out_offset
,
1080 "console_vtermno: %u\n", port
->cons
.vtermno
);
1082 ret
= simple_read_from_buffer(ubuf
, count
, offp
, buf
, out_offset
);
1087 static const struct file_operations port_debugfs_ops
= {
1088 .owner
= THIS_MODULE
,
1089 .open
= debugfs_open
,
1090 .read
= debugfs_read
,
1093 static void set_console_size(struct port
*port
, u16 rows
, u16 cols
)
1095 if (!port
|| !is_console_port(port
))
1098 port
->cons
.ws
.ws_row
= rows
;
1099 port
->cons
.ws
.ws_col
= cols
;
1102 static unsigned int fill_queue(struct virtqueue
*vq
, spinlock_t
*lock
)
1104 struct port_buffer
*buf
;
1105 unsigned int nr_added_bufs
;
1110 buf
= alloc_buf(PAGE_SIZE
);
1114 spin_lock_irq(lock
);
1115 ret
= add_inbuf(vq
, buf
);
1117 spin_unlock_irq(lock
);
1122 spin_unlock_irq(lock
);
1125 return nr_added_bufs
;
1128 static void send_sigio_to_port(struct port
*port
)
1130 if (port
->async_queue
&& port
->guest_connected
)
1131 kill_fasync(&port
->async_queue
, SIGIO
, POLL_OUT
);
1134 static int add_port(struct ports_device
*portdev
, u32 id
)
1136 char debugfs_name
[16];
1138 struct port_buffer
*buf
;
1140 unsigned int nr_added_bufs
;
1143 port
= kmalloc(sizeof(*port
), GFP_KERNEL
);
1148 kref_init(&port
->kref
);
1150 port
->portdev
= portdev
;
1155 port
->cons
.hvc
= NULL
;
1156 port
->async_queue
= NULL
;
1158 port
->cons
.ws
.ws_row
= port
->cons
.ws
.ws_col
= 0;
1160 port
->host_connected
= port
->guest_connected
= false;
1161 port
->stats
= (struct port_stats
) { 0 };
1163 port
->outvq_full
= false;
1165 port
->in_vq
= portdev
->in_vqs
[port
->id
];
1166 port
->out_vq
= portdev
->out_vqs
[port
->id
];
1168 port
->cdev
= cdev_alloc();
1170 dev_err(&port
->portdev
->vdev
->dev
, "Error allocating cdev\n");
1174 port
->cdev
->ops
= &port_fops
;
1176 devt
= MKDEV(portdev
->chr_major
, id
);
1177 err
= cdev_add(port
->cdev
, devt
, 1);
1179 dev_err(&port
->portdev
->vdev
->dev
,
1180 "Error %d adding cdev for port %u\n", err
, id
);
1183 port
->dev
= device_create(pdrvdata
.class, &port
->portdev
->vdev
->dev
,
1184 devt
, port
, "vport%up%u",
1185 port
->portdev
->drv_index
, id
);
1186 if (IS_ERR(port
->dev
)) {
1187 err
= PTR_ERR(port
->dev
);
1188 dev_err(&port
->portdev
->vdev
->dev
,
1189 "Error %d creating device for port %u\n",
1194 spin_lock_init(&port
->inbuf_lock
);
1195 spin_lock_init(&port
->outvq_lock
);
1196 init_waitqueue_head(&port
->waitqueue
);
1198 /* Fill the in_vq with buffers so the host can send us data. */
1199 nr_added_bufs
= fill_queue(port
->in_vq
, &port
->inbuf_lock
);
1200 if (!nr_added_bufs
) {
1201 dev_err(port
->dev
, "Error allocating inbufs\n");
1207 * If we're not using multiport support, this has to be a console port
1209 if (!use_multiport(port
->portdev
)) {
1210 err
= init_port_console(port
);
1215 spin_lock_irq(&portdev
->ports_lock
);
1216 list_add_tail(&port
->list
, &port
->portdev
->ports
);
1217 spin_unlock_irq(&portdev
->ports_lock
);
1220 * Tell the Host we're set so that it can send us various
1221 * configuration parameters for this port (eg, port name,
1222 * caching, whether this is a console port, etc.)
1224 send_control_msg(port
, VIRTIO_CONSOLE_PORT_READY
, 1);
1226 if (pdrvdata
.debugfs_dir
) {
1228 * Finally, create the debugfs file that we can use to
1229 * inspect a port's state at any time
1231 sprintf(debugfs_name
, "vport%up%u",
1232 port
->portdev
->drv_index
, id
);
1233 port
->debugfs_file
= debugfs_create_file(debugfs_name
, 0444,
1234 pdrvdata
.debugfs_dir
,
1241 while ((buf
= virtqueue_detach_unused_buf(port
->in_vq
)))
1244 device_destroy(pdrvdata
.class, port
->dev
->devt
);
1246 cdev_del(port
->cdev
);
1250 /* The host might want to notify management sw about port add failure */
1251 __send_control_msg(portdev
, id
, VIRTIO_CONSOLE_PORT_READY
, 0);
1255 /* No users remain, remove all port-specific data. */
1256 static void remove_port(struct kref
*kref
)
1260 port
= container_of(kref
, struct port
, kref
);
1262 sysfs_remove_group(&port
->dev
->kobj
, &port_attribute_group
);
1263 device_destroy(pdrvdata
.class, port
->dev
->devt
);
1264 cdev_del(port
->cdev
);
1268 debugfs_remove(port
->debugfs_file
);
1274 * Port got unplugged. Remove port from portdev's list and drop the
1275 * kref reference. If no userspace has this port opened, it will
1276 * result in immediate removal the port.
1278 static void unplug_port(struct port
*port
)
1280 struct port_buffer
*buf
;
1282 spin_lock_irq(&port
->portdev
->ports_lock
);
1283 list_del(&port
->list
);
1284 spin_unlock_irq(&port
->portdev
->ports_lock
);
1286 if (port
->guest_connected
) {
1287 port
->guest_connected
= false;
1288 port
->host_connected
= false;
1289 wake_up_interruptible(&port
->waitqueue
);
1291 /* Let the app know the port is going down. */
1292 send_sigio_to_port(port
);
1295 if (is_console_port(port
)) {
1296 spin_lock_irq(&pdrvdata_lock
);
1297 list_del(&port
->cons
.list
);
1298 spin_unlock_irq(&pdrvdata_lock
);
1299 hvc_remove(port
->cons
.hvc
);
1302 /* Remove unused data this port might have received. */
1303 discard_port_data(port
);
1305 reclaim_consumed_buffers(port
);
1307 /* Remove buffers we queued up for the Host to send us data in. */
1308 while ((buf
= virtqueue_detach_unused_buf(port
->in_vq
)))
1312 * We should just assume the device itself has gone off --
1313 * else a close on an open port later will try to send out a
1316 port
->portdev
= NULL
;
1319 * Locks around here are not necessary - a port can't be
1320 * opened after we removed the port struct from ports_list
1323 kref_put(&port
->kref
, remove_port
);
1326 /* Any private messages that the Host and Guest want to share */
1327 static void handle_control_message(struct ports_device
*portdev
,
1328 struct port_buffer
*buf
)
1330 struct virtio_console_control
*cpkt
;
1335 cpkt
= (struct virtio_console_control
*)(buf
->buf
+ buf
->offset
);
1337 port
= find_port_by_id(portdev
, cpkt
->id
);
1338 if (!port
&& cpkt
->event
!= VIRTIO_CONSOLE_PORT_ADD
) {
1339 /* No valid header at start of buffer. Drop it. */
1340 dev_dbg(&portdev
->vdev
->dev
,
1341 "Invalid index %u in control packet\n", cpkt
->id
);
1345 switch (cpkt
->event
) {
1346 case VIRTIO_CONSOLE_PORT_ADD
:
1348 dev_dbg(&portdev
->vdev
->dev
,
1349 "Port %u already added\n", port
->id
);
1350 send_control_msg(port
, VIRTIO_CONSOLE_PORT_READY
, 1);
1353 if (cpkt
->id
>= portdev
->config
.max_nr_ports
) {
1354 dev_warn(&portdev
->vdev
->dev
,
1355 "Request for adding port with out-of-bound id %u, max. supported id: %u\n",
1356 cpkt
->id
, portdev
->config
.max_nr_ports
- 1);
1359 add_port(portdev
, cpkt
->id
);
1361 case VIRTIO_CONSOLE_PORT_REMOVE
:
1364 case VIRTIO_CONSOLE_CONSOLE_PORT
:
1367 if (is_console_port(port
))
1370 init_port_console(port
);
1371 complete(&early_console_added
);
1373 * Could remove the port here in case init fails - but
1374 * have to notify the host first.
1377 case VIRTIO_CONSOLE_RESIZE
: {
1383 if (!is_console_port(port
))
1386 memcpy(&size
, buf
->buf
+ buf
->offset
+ sizeof(*cpkt
),
1388 set_console_size(port
, size
.rows
, size
.cols
);
1390 port
->cons
.hvc
->irq_requested
= 1;
1391 resize_console(port
);
1394 case VIRTIO_CONSOLE_PORT_OPEN
:
1395 port
->host_connected
= cpkt
->value
;
1396 wake_up_interruptible(&port
->waitqueue
);
1398 * If the host port got closed and the host had any
1399 * unconsumed buffers, we'll be able to reclaim them
1402 spin_lock_irq(&port
->outvq_lock
);
1403 reclaim_consumed_buffers(port
);
1404 spin_unlock_irq(&port
->outvq_lock
);
1407 * If the guest is connected, it'll be interested in
1408 * knowing the host connection state changed.
1410 send_sigio_to_port(port
);
1412 case VIRTIO_CONSOLE_PORT_NAME
:
1414 * If we woke up after hibernation, we can get this
1415 * again. Skip it in that case.
1421 * Skip the size of the header and the cpkt to get the size
1422 * of the name that was sent
1424 name_size
= buf
->len
- buf
->offset
- sizeof(*cpkt
) + 1;
1426 port
->name
= kmalloc(name_size
, GFP_KERNEL
);
1429 "Not enough space to store port name\n");
1432 strncpy(port
->name
, buf
->buf
+ buf
->offset
+ sizeof(*cpkt
),
1434 port
->name
[name_size
- 1] = 0;
1437 * Since we only have one sysfs attribute, 'name',
1438 * create it only if we have a name for the port.
1440 err
= sysfs_create_group(&port
->dev
->kobj
,
1441 &port_attribute_group
);
1444 "Error %d creating sysfs device attributes\n",
1448 * Generate a udev event so that appropriate
1449 * symlinks can be created based on udev
1452 kobject_uevent(&port
->dev
->kobj
, KOBJ_CHANGE
);
1458 static void control_work_handler(struct work_struct
*work
)
1460 struct ports_device
*portdev
;
1461 struct virtqueue
*vq
;
1462 struct port_buffer
*buf
;
1465 portdev
= container_of(work
, struct ports_device
, control_work
);
1466 vq
= portdev
->c_ivq
;
1468 spin_lock(&portdev
->cvq_lock
);
1469 while ((buf
= virtqueue_get_buf(vq
, &len
))) {
1470 spin_unlock(&portdev
->cvq_lock
);
1475 handle_control_message(portdev
, buf
);
1477 spin_lock(&portdev
->cvq_lock
);
1478 if (add_inbuf(portdev
->c_ivq
, buf
) < 0) {
1479 dev_warn(&portdev
->vdev
->dev
,
1480 "Error adding buffer to queue\n");
1484 spin_unlock(&portdev
->cvq_lock
);
1487 static void out_intr(struct virtqueue
*vq
)
1491 port
= find_port_by_vq(vq
->vdev
->priv
, vq
);
1495 wake_up_interruptible(&port
->waitqueue
);
1498 static void in_intr(struct virtqueue
*vq
)
1501 unsigned long flags
;
1503 port
= find_port_by_vq(vq
->vdev
->priv
, vq
);
1507 spin_lock_irqsave(&port
->inbuf_lock
, flags
);
1508 port
->inbuf
= get_inbuf(port
);
1511 * Don't queue up data when port is closed. This condition
1512 * can be reached when a console port is not yet connected (no
1513 * tty is spawned) and the host sends out data to console
1514 * ports. For generic serial ports, the host won't
1515 * (shouldn't) send data till the guest is connected.
1517 if (!port
->guest_connected
)
1518 discard_port_data(port
);
1520 spin_unlock_irqrestore(&port
->inbuf_lock
, flags
);
1522 wake_up_interruptible(&port
->waitqueue
);
1524 /* Send a SIGIO indicating new data in case the process asked for it */
1525 send_sigio_to_port(port
);
1527 if (is_console_port(port
) && hvc_poll(port
->cons
.hvc
))
1531 static void control_intr(struct virtqueue
*vq
)
1533 struct ports_device
*portdev
;
1535 portdev
= vq
->vdev
->priv
;
1536 schedule_work(&portdev
->control_work
);
1539 static void config_intr(struct virtio_device
*vdev
)
1541 struct ports_device
*portdev
;
1543 portdev
= vdev
->priv
;
1545 if (!use_multiport(portdev
)) {
1549 vdev
->config
->get(vdev
,
1550 offsetof(struct virtio_console_config
, cols
),
1551 &cols
, sizeof(u16
));
1552 vdev
->config
->get(vdev
,
1553 offsetof(struct virtio_console_config
, rows
),
1554 &rows
, sizeof(u16
));
1556 port
= find_port_by_id(portdev
, 0);
1557 set_console_size(port
, rows
, cols
);
1560 * We'll use this way of resizing only for legacy
1561 * support. For newer userspace
1562 * (VIRTIO_CONSOLE_F_MULTPORT+), use control messages
1563 * to indicate console size changes so that it can be
1566 resize_console(port
);
1570 static int init_vqs(struct ports_device
*portdev
)
1572 vq_callback_t
**io_callbacks
;
1574 struct virtqueue
**vqs
;
1575 u32 i
, j
, nr_ports
, nr_queues
;
1578 nr_ports
= portdev
->config
.max_nr_ports
;
1579 nr_queues
= use_multiport(portdev
) ? (nr_ports
+ 1) * 2 : 2;
1581 vqs
= kmalloc(nr_queues
* sizeof(struct virtqueue
*), GFP_KERNEL
);
1582 io_callbacks
= kmalloc(nr_queues
* sizeof(vq_callback_t
*), GFP_KERNEL
);
1583 io_names
= kmalloc(nr_queues
* sizeof(char *), GFP_KERNEL
);
1584 portdev
->in_vqs
= kmalloc(nr_ports
* sizeof(struct virtqueue
*),
1586 portdev
->out_vqs
= kmalloc(nr_ports
* sizeof(struct virtqueue
*),
1588 if (!vqs
|| !io_callbacks
|| !io_names
|| !portdev
->in_vqs
||
1589 !portdev
->out_vqs
) {
1595 * For backward compat (newer host but older guest), the host
1596 * spawns a console port first and also inits the vqs for port
1600 io_callbacks
[j
] = in_intr
;
1601 io_callbacks
[j
+ 1] = out_intr
;
1602 io_names
[j
] = "input";
1603 io_names
[j
+ 1] = "output";
1606 if (use_multiport(portdev
)) {
1607 io_callbacks
[j
] = control_intr
;
1608 io_callbacks
[j
+ 1] = NULL
;
1609 io_names
[j
] = "control-i";
1610 io_names
[j
+ 1] = "control-o";
1612 for (i
= 1; i
< nr_ports
; i
++) {
1614 io_callbacks
[j
] = in_intr
;
1615 io_callbacks
[j
+ 1] = out_intr
;
1616 io_names
[j
] = "input";
1617 io_names
[j
+ 1] = "output";
1620 /* Find the queues. */
1621 err
= portdev
->vdev
->config
->find_vqs(portdev
->vdev
, nr_queues
, vqs
,
1623 (const char **)io_names
);
1628 portdev
->in_vqs
[0] = vqs
[0];
1629 portdev
->out_vqs
[0] = vqs
[1];
1631 if (use_multiport(portdev
)) {
1632 portdev
->c_ivq
= vqs
[j
];
1633 portdev
->c_ovq
= vqs
[j
+ 1];
1635 for (i
= 1; i
< nr_ports
; i
++) {
1637 portdev
->in_vqs
[i
] = vqs
[j
];
1638 portdev
->out_vqs
[i
] = vqs
[j
+ 1];
1642 kfree(io_callbacks
);
1648 kfree(portdev
->out_vqs
);
1649 kfree(portdev
->in_vqs
);
1651 kfree(io_callbacks
);
1657 static const struct file_operations portdev_fops
= {
1658 .owner
= THIS_MODULE
,
1662 * Once we're further in boot, we get probed like any other virtio
1665 * If the host also supports multiple console ports, we check the
1666 * config space to see how many ports the host has spawned. We
1667 * initialize each port found.
1669 static int __devinit
virtcons_probe(struct virtio_device
*vdev
)
1671 struct ports_device
*portdev
;
1674 bool early
= early_put_chars
!= NULL
;
1676 /* Ensure to read early_put_chars now */
1679 portdev
= kmalloc(sizeof(*portdev
), GFP_KERNEL
);
1685 /* Attach this portdev to this virtio_device, and vice-versa. */
1686 portdev
->vdev
= vdev
;
1687 vdev
->priv
= portdev
;
1689 spin_lock_irq(&pdrvdata_lock
);
1690 portdev
->drv_index
= pdrvdata
.index
++;
1691 spin_unlock_irq(&pdrvdata_lock
);
1693 portdev
->chr_major
= register_chrdev(0, "virtio-portsdev",
1695 if (portdev
->chr_major
< 0) {
1697 "Error %d registering chrdev for device %u\n",
1698 portdev
->chr_major
, portdev
->drv_index
);
1699 err
= portdev
->chr_major
;
1704 portdev
->config
.max_nr_ports
= 1;
1705 if (virtio_config_val(vdev
, VIRTIO_CONSOLE_F_MULTIPORT
,
1706 offsetof(struct virtio_console_config
,
1708 &portdev
->config
.max_nr_ports
) == 0)
1711 err
= init_vqs(portdev
);
1713 dev_err(&vdev
->dev
, "Error %d initializing vqs\n", err
);
1717 spin_lock_init(&portdev
->ports_lock
);
1718 INIT_LIST_HEAD(&portdev
->ports
);
1721 unsigned int nr_added_bufs
;
1723 spin_lock_init(&portdev
->cvq_lock
);
1724 INIT_WORK(&portdev
->control_work
, &control_work_handler
);
1726 nr_added_bufs
= fill_queue(portdev
->c_ivq
, &portdev
->cvq_lock
);
1727 if (!nr_added_bufs
) {
1729 "Error allocating buffers for control queue\n");
1735 * For backward compatibility: Create a console port
1736 * if we're running on older host.
1738 add_port(portdev
, 0);
1741 spin_lock_irq(&pdrvdata_lock
);
1742 list_add_tail(&portdev
->list
, &pdrvdata
.portdevs
);
1743 spin_unlock_irq(&pdrvdata_lock
);
1745 __send_control_msg(portdev
, VIRTIO_CONSOLE_BAD_ID
,
1746 VIRTIO_CONSOLE_DEVICE_READY
, 1);
1749 * If there was an early virtio console, assume that there are no
1750 * other consoles. We need to wait until the hvc_alloc matches the
1751 * hvc_instantiate, otherwise tty_open will complain, resulting in
1752 * a "Warning: unable to open an initial console" boot failure.
1753 * Without multiport this is done in add_port above. With multiport
1754 * this might take some host<->guest communication - thus we have to
1757 if (multiport
&& early
)
1758 wait_for_completion(&early_console_added
);
1763 /* The host might want to notify mgmt sw about device add failure */
1764 __send_control_msg(portdev
, VIRTIO_CONSOLE_BAD_ID
,
1765 VIRTIO_CONSOLE_DEVICE_READY
, 0);
1766 vdev
->config
->del_vqs(vdev
);
1767 kfree(portdev
->in_vqs
);
1768 kfree(portdev
->out_vqs
);
1770 unregister_chrdev(portdev
->chr_major
, "virtio-portsdev");
1777 static void virtcons_remove(struct virtio_device
*vdev
)
1779 struct ports_device
*portdev
;
1780 struct port
*port
, *port2
;
1782 portdev
= vdev
->priv
;
1784 spin_lock_irq(&pdrvdata_lock
);
1785 list_del(&portdev
->list
);
1786 spin_unlock_irq(&pdrvdata_lock
);
1788 /* Disable interrupts for vqs */
1789 vdev
->config
->reset(vdev
);
1790 /* Finish up work that's lined up */
1791 cancel_work_sync(&portdev
->control_work
);
1793 list_for_each_entry_safe(port
, port2
, &portdev
->ports
, list
)
1796 unregister_chrdev(portdev
->chr_major
, "virtio-portsdev");
1799 * When yanking out a device, we immediately lose the
1800 * (device-side) queues. So there's no point in keeping the
1801 * guest side around till we drop our final reference. This
1802 * also means that any ports which are in an open state will
1803 * have to just stop using the port, as the vqs are going
1806 if (use_multiport(portdev
)) {
1807 struct port_buffer
*buf
;
1810 while ((buf
= virtqueue_get_buf(portdev
->c_ivq
, &len
)))
1813 while ((buf
= virtqueue_detach_unused_buf(portdev
->c_ivq
)))
1817 vdev
->config
->del_vqs(vdev
);
1818 kfree(portdev
->in_vqs
);
1819 kfree(portdev
->out_vqs
);
1824 static struct virtio_device_id id_table
[] = {
1825 { VIRTIO_ID_CONSOLE
, VIRTIO_DEV_ANY_ID
},
1829 static unsigned int features
[] = {
1830 VIRTIO_CONSOLE_F_SIZE
,
1831 VIRTIO_CONSOLE_F_MULTIPORT
,
1834 static struct virtio_driver virtio_console
= {
1835 .feature_table
= features
,
1836 .feature_table_size
= ARRAY_SIZE(features
),
1837 .driver
.name
= KBUILD_MODNAME
,
1838 .driver
.owner
= THIS_MODULE
,
1839 .id_table
= id_table
,
1840 .probe
= virtcons_probe
,
1841 .remove
= virtcons_remove
,
1842 .config_changed
= config_intr
,
1845 static int __init
init(void)
1849 pdrvdata
.class = class_create(THIS_MODULE
, "virtio-ports");
1850 if (IS_ERR(pdrvdata
.class)) {
1851 err
= PTR_ERR(pdrvdata
.class);
1852 pr_err("Error %d creating virtio-ports class\n", err
);
1856 pdrvdata
.debugfs_dir
= debugfs_create_dir("virtio-ports", NULL
);
1857 if (!pdrvdata
.debugfs_dir
) {
1858 pr_warning("Error %ld creating debugfs dir for virtio-ports\n",
1859 PTR_ERR(pdrvdata
.debugfs_dir
));
1861 INIT_LIST_HEAD(&pdrvdata
.consoles
);
1862 INIT_LIST_HEAD(&pdrvdata
.portdevs
);
1864 return register_virtio_driver(&virtio_console
);
1867 static void __exit
fini(void)
1869 unregister_virtio_driver(&virtio_console
);
1871 class_destroy(pdrvdata
.class);
1872 if (pdrvdata
.debugfs_dir
)
1873 debugfs_remove_recursive(pdrvdata
.debugfs_dir
);
1878 MODULE_DEVICE_TABLE(virtio
, id_table
);
1879 MODULE_DESCRIPTION("Virtio console driver");
1880 MODULE_LICENSE("GPL");