xref: /freebsd/sys/dev/virtio/console/virtio_console.c (revision 6be3386466ab79a84b48429ae66244f21526d3df)
1 /*-
2  * Copyright (c) 2014, Bryan Venteicher <bryanv@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice unmodified, this list of conditions, and the following
10  *    disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  */
26 
27 /* Driver for VirtIO console devices. */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/ctype.h>
34 #include <sys/systm.h>
35 #include <sys/kernel.h>
36 #include <sys/malloc.h>
37 #include <sys/module.h>
38 #include <sys/kdb.h>
39 #include <sys/lock.h>
40 #include <sys/mutex.h>
41 #include <sys/sglist.h>
42 #include <sys/sysctl.h>
43 #include <sys/taskqueue.h>
44 #include <sys/queue.h>
45 
46 #include <sys/conf.h>
47 #include <sys/cons.h>
48 #include <sys/tty.h>
49 
50 #include <machine/bus.h>
51 #include <machine/resource.h>
52 #include <sys/bus.h>
53 
54 #include <dev/virtio/virtio.h>
55 #include <dev/virtio/virtqueue.h>
56 #include <dev/virtio/console/virtio_console.h>
57 
58 #include "virtio_if.h"
59 
60 #define VTCON_MAX_PORTS 32
61 #define VTCON_TTY_PREFIX "V"
62 #define VTCON_TTY_ALIAS_PREFIX "vtcon"
63 #define VTCON_BULK_BUFSZ 128
64 #define VTCON_CTRL_BUFSZ 128
65 
66 /*
67  * The buffers cannot cross more than one page boundary due to the
68  * size of the sglist segment array used.
69  */
70 CTASSERT(VTCON_BULK_BUFSZ <= PAGE_SIZE);
71 CTASSERT(VTCON_CTRL_BUFSZ <= PAGE_SIZE);
72 
73 CTASSERT(sizeof(struct virtio_console_config) <= VTCON_CTRL_BUFSZ);
74 
75 struct vtcon_softc;
76 struct vtcon_softc_port;
77 
78 struct vtcon_port {
79 	struct mtx			 vtcport_mtx;
80 	struct vtcon_softc		*vtcport_sc;
81 	struct vtcon_softc_port		*vtcport_scport;
82 	struct tty			*vtcport_tty;
83 	struct virtqueue		*vtcport_invq;
84 	struct virtqueue		*vtcport_outvq;
85 	int				 vtcport_id;
86 	int				 vtcport_flags;
87 #define VTCON_PORT_FLAG_GONE	0x01
88 #define VTCON_PORT_FLAG_CONSOLE	0x02
89 #define VTCON_PORT_FLAG_ALIAS	0x04
90 
91 #if defined(KDB)
92 	int				 vtcport_alt_break_state;
93 #endif
94 };
95 
96 #define VTCON_PORT_LOCK(_port)		mtx_lock(&(_port)->vtcport_mtx)
97 #define VTCON_PORT_UNLOCK(_port)	mtx_unlock(&(_port)->vtcport_mtx)
98 
99 struct vtcon_softc_port {
100 	struct vtcon_softc	*vcsp_sc;
101 	struct vtcon_port	*vcsp_port;
102 	struct virtqueue	*vcsp_invq;
103 	struct virtqueue	*vcsp_outvq;
104 };
105 
106 struct vtcon_softc {
107 	device_t		 vtcon_dev;
108 	struct mtx		 vtcon_mtx;
109 	uint64_t		 vtcon_features;
110 	uint32_t		 vtcon_max_ports;
111 	uint32_t		 vtcon_flags;
112 #define VTCON_FLAG_DETACHED	0x01
113 #define VTCON_FLAG_SIZE		0x02
114 #define VTCON_FLAG_MULTIPORT	0x04
115 
116 	/*
117 	 * Ports can be added and removed during runtime, but we have
118 	 * to allocate all the virtqueues during attach. This array is
119 	 * indexed by the port ID.
120 	 */
121 	struct vtcon_softc_port	*vtcon_ports;
122 
123 	struct task		 vtcon_ctrl_task;
124 	struct virtqueue	*vtcon_ctrl_rxvq;
125 	struct virtqueue	*vtcon_ctrl_txvq;
126 	struct mtx		 vtcon_ctrl_tx_mtx;
127 };
128 
129 #define VTCON_LOCK(_sc)			mtx_lock(&(_sc)->vtcon_mtx)
130 #define VTCON_UNLOCK(_sc)		mtx_unlock(&(_sc)->vtcon_mtx)
131 #define VTCON_LOCK_ASSERT(_sc)		\
132     mtx_assert(&(_sc)->vtcon_mtx, MA_OWNED)
133 #define VTCON_LOCK_ASSERT_NOTOWNED(_sc)	\
134     mtx_assert(&(_sc)->vtcon_mtx, MA_NOTOWNED)
135 
136 #define VTCON_CTRL_TX_LOCK(_sc)		mtx_lock(&(_sc)->vtcon_ctrl_tx_mtx)
137 #define VTCON_CTRL_TX_UNLOCK(_sc)	mtx_unlock(&(_sc)->vtcon_ctrl_tx_mtx)
138 
139 #define VTCON_ASSERT_VALID_PORTID(_sc, _id)			\
140     KASSERT((_id) >= 0 && (_id) < (_sc)->vtcon_max_ports,	\
141         ("%s: port ID %d out of range", __func__, _id))
142 
143 #define VTCON_FEATURES  VIRTIO_CONSOLE_F_MULTIPORT
144 
145 static struct virtio_feature_desc vtcon_feature_desc[] = {
146 	{ VIRTIO_CONSOLE_F_SIZE,	"ConsoleSize"	},
147 	{ VIRTIO_CONSOLE_F_MULTIPORT,	"MultiplePorts"	},
148 	{ VIRTIO_CONSOLE_F_EMERG_WRITE,	"EmergencyWrite" },
149 	{ 0, NULL }
150 };
151 
152 static int	 vtcon_modevent(module_t, int, void *);
153 static void	 vtcon_drain_all(void);
154 
155 static int	 vtcon_probe(device_t);
156 static int	 vtcon_attach(device_t);
157 static int	 vtcon_detach(device_t);
158 static int	 vtcon_config_change(device_t);
159 
160 static int	 vtcon_setup_features(struct vtcon_softc *);
161 static int	 vtcon_negotiate_features(struct vtcon_softc *);
162 static int	 vtcon_alloc_scports(struct vtcon_softc *);
163 static int	 vtcon_alloc_virtqueues(struct vtcon_softc *);
164 static void	 vtcon_read_config(struct vtcon_softc *,
165 		     struct virtio_console_config *);
166 
167 static void	 vtcon_determine_max_ports(struct vtcon_softc *,
168 		     struct virtio_console_config *);
169 static void	 vtcon_destroy_ports(struct vtcon_softc *);
170 static void	 vtcon_stop(struct vtcon_softc *);
171 
172 static int	 vtcon_ctrl_event_enqueue(struct vtcon_softc *,
173 		     struct virtio_console_control *);
174 static int	 vtcon_ctrl_event_create(struct vtcon_softc *);
175 static void	 vtcon_ctrl_event_requeue(struct vtcon_softc *,
176 		     struct virtio_console_control *);
177 static int	 vtcon_ctrl_event_populate(struct vtcon_softc *);
178 static void	 vtcon_ctrl_event_drain(struct vtcon_softc *);
179 static int	 vtcon_ctrl_init(struct vtcon_softc *);
180 static void	 vtcon_ctrl_deinit(struct vtcon_softc *);
181 static void	 vtcon_ctrl_port_add_event(struct vtcon_softc *, int);
182 static void	 vtcon_ctrl_port_remove_event(struct vtcon_softc *, int);
183 static void	 vtcon_ctrl_port_console_event(struct vtcon_softc *, int);
184 static void	 vtcon_ctrl_port_open_event(struct vtcon_softc *, int);
185 static void	 vtcon_ctrl_port_name_event(struct vtcon_softc *, int,
186 		     const char *, size_t);
187 static void	 vtcon_ctrl_process_event(struct vtcon_softc *,
188 		     struct virtio_console_control *, void *, size_t);
189 static void	 vtcon_ctrl_task_cb(void *, int);
190 static void	 vtcon_ctrl_event_intr(void *);
191 static void	 vtcon_ctrl_poll(struct vtcon_softc *,
192 		     struct virtio_console_control *control);
193 static void	 vtcon_ctrl_send_control(struct vtcon_softc *, uint32_t,
194 		     uint16_t, uint16_t);
195 
196 static int	 vtcon_port_enqueue_buf(struct vtcon_port *, void *, size_t);
197 static int	 vtcon_port_create_buf(struct vtcon_port *);
198 static void	 vtcon_port_requeue_buf(struct vtcon_port *, void *);
199 static int	 vtcon_port_populate(struct vtcon_port *);
200 static void	 vtcon_port_destroy(struct vtcon_port *);
201 static int	 vtcon_port_create(struct vtcon_softc *, int);
202 static void	 vtcon_port_dev_alias(struct vtcon_port *, const char *,
203 		     size_t);
204 static void	 vtcon_port_drain_bufs(struct virtqueue *);
205 static void	 vtcon_port_drain(struct vtcon_port *);
206 static void	 vtcon_port_teardown(struct vtcon_port *);
207 static void	 vtcon_port_change_size(struct vtcon_port *, uint16_t,
208 		     uint16_t);
209 static void	 vtcon_port_update_console_size(struct vtcon_softc *);
210 static void	 vtcon_port_enable_intr(struct vtcon_port *);
211 static void	 vtcon_port_disable_intr(struct vtcon_port *);
212 static void	 vtcon_port_in(struct vtcon_port *);
213 static void	 vtcon_port_intr(void *);
214 static void	 vtcon_port_out(struct vtcon_port *, void *, int);
215 static void	 vtcon_port_submit_event(struct vtcon_port *, uint16_t,
216 		     uint16_t);
217 
218 static int	 vtcon_tty_open(struct tty *);
219 static void	 vtcon_tty_close(struct tty *);
220 static void	 vtcon_tty_outwakeup(struct tty *);
221 static void	 vtcon_tty_free(void *);
222 
223 static void	 vtcon_get_console_size(struct vtcon_softc *, uint16_t *,
224 		     uint16_t *);
225 
226 static void	 vtcon_enable_interrupts(struct vtcon_softc *);
227 static void	 vtcon_disable_interrupts(struct vtcon_softc *);
228 
229 #define vtcon_modern(_sc) (((_sc)->vtcon_features & VIRTIO_F_VERSION_1) != 0)
230 #define vtcon_htog16(_sc, _val)	virtio_htog16(vtcon_modern(_sc), _val)
231 #define vtcon_htog32(_sc, _val)	virtio_htog32(vtcon_modern(_sc), _val)
232 #define vtcon_htog64(_sc, _val)	virtio_htog64(vtcon_modern(_sc), _val)
233 #define vtcon_gtoh16(_sc, _val)	virtio_gtoh16(vtcon_modern(_sc), _val)
234 #define vtcon_gtoh32(_sc, _val)	virtio_gtoh32(vtcon_modern(_sc), _val)
235 #define vtcon_gtoh64(_sc, _val)	virtio_gtoh64(vtcon_modern(_sc), _val)
236 
237 static int	 vtcon_pending_free;
238 
239 static struct ttydevsw vtcon_tty_class = {
240 	.tsw_flags	= 0,
241 	.tsw_open	= vtcon_tty_open,
242 	.tsw_close	= vtcon_tty_close,
243 	.tsw_outwakeup	= vtcon_tty_outwakeup,
244 	.tsw_free	= vtcon_tty_free,
245 };
246 
247 static device_method_t vtcon_methods[] = {
248 	/* Device methods. */
249 	DEVMETHOD(device_probe,		vtcon_probe),
250 	DEVMETHOD(device_attach,	vtcon_attach),
251 	DEVMETHOD(device_detach,	vtcon_detach),
252 
253 	/* VirtIO methods. */
254 	DEVMETHOD(virtio_config_change,	vtcon_config_change),
255 
256 	DEVMETHOD_END
257 };
258 
259 static driver_t vtcon_driver = {
260 	"vtcon",
261 	vtcon_methods,
262 	sizeof(struct vtcon_softc)
263 };
264 static devclass_t vtcon_devclass;
265 
266 VIRTIO_DRIVER_MODULE(virtio_console, vtcon_driver, vtcon_devclass,
267     vtcon_modevent, 0);
268 MODULE_VERSION(virtio_console, 1);
269 MODULE_DEPEND(virtio_console, virtio, 1, 1, 1);
270 
271 VIRTIO_SIMPLE_PNPINFO(virtio_console, VIRTIO_ID_CONSOLE,
272     "VirtIO Console Adapter");
273 
274 static int
275 vtcon_modevent(module_t mod, int type, void *unused)
276 {
277 	int error;
278 
279 	switch (type) {
280 	case MOD_LOAD:
281 		error = 0;
282 		break;
283 	case MOD_QUIESCE:
284 		error = 0;
285 		break;
286 	case MOD_UNLOAD:
287 		vtcon_drain_all();
288 		error = 0;
289 		break;
290 	case MOD_SHUTDOWN:
291 		error = 0;
292 		break;
293 	default:
294 		error = EOPNOTSUPP;
295 		break;
296 	}
297 
298 	return (error);
299 }
300 
301 static void
302 vtcon_drain_all(void)
303 {
304 	int first;
305 
306 	for (first = 1; vtcon_pending_free != 0; first = 0) {
307 		if (first != 0) {
308 			printf("virtio_console: Waiting for all detached TTY "
309 			    "devices to have open fds closed.\n");
310 		}
311 		pause("vtcondra", hz);
312 	}
313 }
314 
315 static int
316 vtcon_probe(device_t dev)
317 {
318 	return (VIRTIO_SIMPLE_PROBE(dev, virtio_console));
319 }
320 
321 static int
322 vtcon_attach(device_t dev)
323 {
324 	struct vtcon_softc *sc;
325 	struct virtio_console_config concfg;
326 	int error;
327 
328 	sc = device_get_softc(dev);
329 	sc->vtcon_dev = dev;
330 	virtio_set_feature_desc(dev, vtcon_feature_desc);
331 
332 	mtx_init(&sc->vtcon_mtx, "vtconmtx", NULL, MTX_DEF);
333 	mtx_init(&sc->vtcon_ctrl_tx_mtx, "vtconctrlmtx", NULL, MTX_DEF);
334 
335 	error = vtcon_setup_features(sc);
336 	if (error) {
337 		device_printf(dev, "cannot setup features\n");
338 		goto fail;
339 	}
340 
341 	vtcon_read_config(sc, &concfg);
342 	vtcon_determine_max_ports(sc, &concfg);
343 
344 	error = vtcon_alloc_scports(sc);
345 	if (error) {
346 		device_printf(dev, "cannot allocate softc port structures\n");
347 		goto fail;
348 	}
349 
350 	error = vtcon_alloc_virtqueues(sc);
351 	if (error) {
352 		device_printf(dev, "cannot allocate virtqueues\n");
353 		goto fail;
354 	}
355 
356 	if (sc->vtcon_flags & VTCON_FLAG_MULTIPORT) {
357 		TASK_INIT(&sc->vtcon_ctrl_task, 0, vtcon_ctrl_task_cb, sc);
358 		error = vtcon_ctrl_init(sc);
359 		if (error)
360 			goto fail;
361 	} else {
362 		error = vtcon_port_create(sc, 0);
363 		if (error)
364 			goto fail;
365 		if (sc->vtcon_flags & VTCON_FLAG_SIZE)
366 			vtcon_port_update_console_size(sc);
367 	}
368 
369 	error = virtio_setup_intr(dev, INTR_TYPE_TTY);
370 	if (error) {
371 		device_printf(dev, "cannot setup virtqueue interrupts\n");
372 		goto fail;
373 	}
374 
375 	vtcon_enable_interrupts(sc);
376 
377 	vtcon_ctrl_send_control(sc, VIRTIO_CONSOLE_BAD_ID,
378 	    VIRTIO_CONSOLE_DEVICE_READY, 1);
379 
380 fail:
381 	if (error)
382 		vtcon_detach(dev);
383 
384 	return (error);
385 }
386 
387 static int
388 vtcon_detach(device_t dev)
389 {
390 	struct vtcon_softc *sc;
391 
392 	sc = device_get_softc(dev);
393 
394 	VTCON_LOCK(sc);
395 	sc->vtcon_flags |= VTCON_FLAG_DETACHED;
396 	if (device_is_attached(dev))
397 		vtcon_stop(sc);
398 	VTCON_UNLOCK(sc);
399 
400 	if (sc->vtcon_flags & VTCON_FLAG_MULTIPORT) {
401 		taskqueue_drain(taskqueue_thread, &sc->vtcon_ctrl_task);
402 		vtcon_ctrl_deinit(sc);
403 	}
404 
405 	vtcon_destroy_ports(sc);
406 	mtx_destroy(&sc->vtcon_mtx);
407 	mtx_destroy(&sc->vtcon_ctrl_tx_mtx);
408 
409 	return (0);
410 }
411 
412 static int
413 vtcon_config_change(device_t dev)
414 {
415 	struct vtcon_softc *sc;
416 
417 	sc = device_get_softc(dev);
418 
419 	/*
420 	 * When the multiport feature is negotiated, all configuration
421 	 * changes are done through control virtqueue events.
422 	 */
423 	if ((sc->vtcon_flags & VTCON_FLAG_MULTIPORT) == 0) {
424 		if (sc->vtcon_flags & VTCON_FLAG_SIZE)
425 			vtcon_port_update_console_size(sc);
426 	}
427 
428 	return (0);
429 }
430 
431 static int
432 vtcon_negotiate_features(struct vtcon_softc *sc)
433 {
434 	device_t dev;
435 	uint64_t features;
436 
437 	dev = sc->vtcon_dev;
438 	features = VTCON_FEATURES;
439 
440 	sc->vtcon_features = virtio_negotiate_features(dev, features);
441 	return (virtio_finalize_features(dev));
442 }
443 
444 static int
445 vtcon_setup_features(struct vtcon_softc *sc)
446 {
447 	device_t dev;
448 	int error;
449 
450 	dev = sc->vtcon_dev;
451 
452 	error = vtcon_negotiate_features(sc);
453 	if (error)
454 		return (error);
455 
456 	if (virtio_with_feature(dev, VIRTIO_CONSOLE_F_SIZE))
457 		sc->vtcon_flags |= VTCON_FLAG_SIZE;
458 	if (virtio_with_feature(dev, VIRTIO_CONSOLE_F_MULTIPORT))
459 		sc->vtcon_flags |= VTCON_FLAG_MULTIPORT;
460 
461 	return (0);
462 }
463 
464 #define VTCON_GET_CONFIG(_dev, _feature, _field, _cfg)			\
465 	if (virtio_with_feature(_dev, _feature)) {			\
466 		virtio_read_device_config(_dev,				\
467 		    offsetof(struct virtio_console_config, _field),	\
468 		    &(_cfg)->_field, sizeof((_cfg)->_field));		\
469 	}
470 
471 static void
472 vtcon_read_config(struct vtcon_softc *sc, struct virtio_console_config *concfg)
473 {
474 	device_t dev;
475 
476 	dev = sc->vtcon_dev;
477 
478 	bzero(concfg, sizeof(struct virtio_console_config));
479 
480 	VTCON_GET_CONFIG(dev, VIRTIO_CONSOLE_F_SIZE, cols, concfg);
481 	VTCON_GET_CONFIG(dev, VIRTIO_CONSOLE_F_SIZE, rows, concfg);
482 	VTCON_GET_CONFIG(dev, VIRTIO_CONSOLE_F_MULTIPORT, max_nr_ports, concfg);
483 }
484 
485 #undef VTCON_GET_CONFIG
486 
487 static int
488 vtcon_alloc_scports(struct vtcon_softc *sc)
489 {
490 	struct vtcon_softc_port *scport;
491 	int max, i;
492 
493 	max = sc->vtcon_max_ports;
494 
495 	sc->vtcon_ports = malloc(sizeof(struct vtcon_softc_port) * max,
496 	    M_DEVBUF, M_NOWAIT | M_ZERO);
497 	if (sc->vtcon_ports == NULL)
498 		return (ENOMEM);
499 
500 	for (i = 0; i < max; i++) {
501 		scport = &sc->vtcon_ports[i];
502 		scport->vcsp_sc = sc;
503 	}
504 
505 	return (0);
506 }
507 
508 static int
509 vtcon_alloc_virtqueues(struct vtcon_softc *sc)
510 {
511 	device_t dev;
512 	struct vq_alloc_info *info;
513 	struct vtcon_softc_port *scport;
514 	int i, idx, portidx, nvqs, error;
515 
516 	dev = sc->vtcon_dev;
517 
518 	nvqs = sc->vtcon_max_ports * 2;
519 	if (sc->vtcon_flags & VTCON_FLAG_MULTIPORT)
520 		nvqs += 2;
521 
522 	info = malloc(sizeof(struct vq_alloc_info) * nvqs, M_TEMP, M_NOWAIT);
523 	if (info == NULL)
524 		return (ENOMEM);
525 
526 	for (i = 0, idx = 0, portidx = 0; i < nvqs / 2; i++, idx += 2) {
527 		if (i == 1) {
528 			/* The control virtqueues are after the first port. */
529 			VQ_ALLOC_INFO_INIT(&info[idx], 0,
530 			    vtcon_ctrl_event_intr, sc, &sc->vtcon_ctrl_rxvq,
531 			    "%s-control rx", device_get_nameunit(dev));
532 			VQ_ALLOC_INFO_INIT(&info[idx+1], 0,
533 			    NULL, sc, &sc->vtcon_ctrl_txvq,
534 			    "%s-control tx", device_get_nameunit(dev));
535 			continue;
536 		}
537 
538 		scport = &sc->vtcon_ports[portidx];
539 
540 		VQ_ALLOC_INFO_INIT(&info[idx], 0, vtcon_port_intr,
541 		    scport, &scport->vcsp_invq, "%s-port%d in",
542 		    device_get_nameunit(dev), i);
543 		VQ_ALLOC_INFO_INIT(&info[idx+1], 0, NULL,
544 		    NULL, &scport->vcsp_outvq, "%s-port%d out",
545 		    device_get_nameunit(dev), i);
546 
547 		portidx++;
548 	}
549 
550 	error = virtio_alloc_virtqueues(dev, 0, nvqs, info);
551 	free(info, M_TEMP);
552 
553 	return (error);
554 }
555 
556 static void
557 vtcon_determine_max_ports(struct vtcon_softc *sc,
558     struct virtio_console_config *concfg)
559 {
560 
561 	if (sc->vtcon_flags & VTCON_FLAG_MULTIPORT) {
562 		sc->vtcon_max_ports =
563 		    min(concfg->max_nr_ports, VTCON_MAX_PORTS);
564 		if (sc->vtcon_max_ports == 0)
565 			sc->vtcon_max_ports = 1;
566 	} else
567 		sc->vtcon_max_ports = 1;
568 }
569 
570 static void
571 vtcon_destroy_ports(struct vtcon_softc *sc)
572 {
573 	struct vtcon_softc_port *scport;
574 	struct vtcon_port *port;
575 	struct virtqueue *vq;
576 	int i;
577 
578 	if (sc->vtcon_ports == NULL)
579 		return;
580 
581 	VTCON_LOCK(sc);
582 	for (i = 0; i < sc->vtcon_max_ports; i++) {
583 		scport = &sc->vtcon_ports[i];
584 
585 		port = scport->vcsp_port;
586 		if (port != NULL) {
587 			scport->vcsp_port = NULL;
588 			VTCON_PORT_LOCK(port);
589 			VTCON_UNLOCK(sc);
590 			vtcon_port_teardown(port);
591 			VTCON_LOCK(sc);
592 		}
593 
594 		vq = scport->vcsp_invq;
595 		if (vq != NULL)
596 			vtcon_port_drain_bufs(vq);
597 	}
598 	VTCON_UNLOCK(sc);
599 
600 	free(sc->vtcon_ports, M_DEVBUF);
601 	sc->vtcon_ports = NULL;
602 }
603 
604 static void
605 vtcon_stop(struct vtcon_softc *sc)
606 {
607 
608 	vtcon_disable_interrupts(sc);
609 	virtio_stop(sc->vtcon_dev);
610 }
611 
612 static int
613 vtcon_ctrl_event_enqueue(struct vtcon_softc *sc,
614     struct virtio_console_control *control)
615 {
616 	struct sglist_seg segs[2];
617 	struct sglist sg;
618 	struct virtqueue *vq;
619 	int error;
620 
621 	vq = sc->vtcon_ctrl_rxvq;
622 
623 	sglist_init(&sg, 2, segs);
624 	error = sglist_append(&sg, control, VTCON_CTRL_BUFSZ);
625 	KASSERT(error == 0, ("%s: error %d adding control to sglist",
626 	    __func__, error));
627 
628 	return (virtqueue_enqueue(vq, control, &sg, 0, sg.sg_nseg));
629 }
630 
631 static int
632 vtcon_ctrl_event_create(struct vtcon_softc *sc)
633 {
634 	struct virtio_console_control *control;
635 	int error;
636 
637 	control = malloc(VTCON_CTRL_BUFSZ, M_DEVBUF, M_ZERO | M_NOWAIT);
638 	if (control == NULL)
639 		return (ENOMEM);
640 
641 	error = vtcon_ctrl_event_enqueue(sc, control);
642 	if (error)
643 		free(control, M_DEVBUF);
644 
645 	return (error);
646 }
647 
648 static void
649 vtcon_ctrl_event_requeue(struct vtcon_softc *sc,
650     struct virtio_console_control *control)
651 {
652 	int error;
653 
654 	bzero(control, VTCON_CTRL_BUFSZ);
655 
656 	error = vtcon_ctrl_event_enqueue(sc, control);
657 	KASSERT(error == 0,
658 	    ("%s: cannot requeue control buffer %d", __func__, error));
659 }
660 
661 static int
662 vtcon_ctrl_event_populate(struct vtcon_softc *sc)
663 {
664 	struct virtqueue *vq;
665 	int nbufs, error;
666 
667 	vq = sc->vtcon_ctrl_rxvq;
668 	error = ENOSPC;
669 
670 	for (nbufs = 0; !virtqueue_full(vq); nbufs++) {
671 		error = vtcon_ctrl_event_create(sc);
672 		if (error)
673 			break;
674 	}
675 
676 	if (nbufs > 0) {
677 		virtqueue_notify(vq);
678 		error = 0;
679 	}
680 
681 	return (error);
682 }
683 
684 static void
685 vtcon_ctrl_event_drain(struct vtcon_softc *sc)
686 {
687 	struct virtio_console_control *control;
688 	struct virtqueue *vq;
689 	int last;
690 
691 	vq = sc->vtcon_ctrl_rxvq;
692 	last = 0;
693 
694 	if (vq == NULL)
695 		return;
696 
697 	VTCON_LOCK(sc);
698 	while ((control = virtqueue_drain(vq, &last)) != NULL)
699 		free(control, M_DEVBUF);
700 	VTCON_UNLOCK(sc);
701 }
702 
703 static int
704 vtcon_ctrl_init(struct vtcon_softc *sc)
705 {
706 	int error;
707 
708 	error = vtcon_ctrl_event_populate(sc);
709 
710 	return (error);
711 }
712 
713 static void
714 vtcon_ctrl_deinit(struct vtcon_softc *sc)
715 {
716 
717 	vtcon_ctrl_event_drain(sc);
718 }
719 
720 static void
721 vtcon_ctrl_port_add_event(struct vtcon_softc *sc, int id)
722 {
723 	device_t dev;
724 	int error;
725 
726 	dev = sc->vtcon_dev;
727 
728 	/* This single thread only way for ports to be created. */
729 	if (sc->vtcon_ports[id].vcsp_port != NULL) {
730 		device_printf(dev, "%s: adding port %d, but already exists\n",
731 		    __func__, id);
732 		return;
733 	}
734 
735 	error = vtcon_port_create(sc, id);
736 	if (error) {
737 		device_printf(dev, "%s: cannot create port %d: %d\n",
738 		    __func__, id, error);
739 		vtcon_ctrl_send_control(sc, id, VIRTIO_CONSOLE_PORT_READY, 0);
740 		return;
741 	}
742 }
743 
744 static void
745 vtcon_ctrl_port_remove_event(struct vtcon_softc *sc, int id)
746 {
747 	device_t dev;
748 	struct vtcon_softc_port *scport;
749 	struct vtcon_port *port;
750 
751 	dev = sc->vtcon_dev;
752 	scport = &sc->vtcon_ports[id];
753 
754 	VTCON_LOCK(sc);
755 	port = scport->vcsp_port;
756 	if (port == NULL) {
757 		VTCON_UNLOCK(sc);
758 		device_printf(dev, "%s: remove port %d, but does not exist\n",
759 		    __func__, id);
760 		return;
761 	}
762 
763 	scport->vcsp_port = NULL;
764 	VTCON_PORT_LOCK(port);
765 	VTCON_UNLOCK(sc);
766 	vtcon_port_teardown(port);
767 }
768 
769 static void
770 vtcon_ctrl_port_console_event(struct vtcon_softc *sc, int id)
771 {
772 	device_t dev;
773 	struct vtcon_softc_port *scport;
774 	struct vtcon_port *port;
775 
776 	dev = sc->vtcon_dev;
777 	scport = &sc->vtcon_ports[id];
778 
779 	VTCON_LOCK(sc);
780 	port = scport->vcsp_port;
781 	if (port == NULL) {
782 		VTCON_UNLOCK(sc);
783 		device_printf(dev, "%s: console port %d, but does not exist\n",
784 		    __func__, id);
785 		return;
786 	}
787 
788 	VTCON_PORT_LOCK(port);
789 	VTCON_UNLOCK(sc);
790 	port->vtcport_flags |= VTCON_PORT_FLAG_CONSOLE;
791 	vtcon_port_submit_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
792 	VTCON_PORT_UNLOCK(port);
793 }
794 
795 static void
796 vtcon_ctrl_port_open_event(struct vtcon_softc *sc, int id)
797 {
798 	device_t dev;
799 	struct vtcon_softc_port *scport;
800 	struct vtcon_port *port;
801 
802 	dev = sc->vtcon_dev;
803 	scport = &sc->vtcon_ports[id];
804 
805 	VTCON_LOCK(sc);
806 	port = scport->vcsp_port;
807 	if (port == NULL) {
808 		VTCON_UNLOCK(sc);
809 		device_printf(dev, "%s: open port %d, but does not exist\n",
810 		    __func__, id);
811 		return;
812 	}
813 
814 	VTCON_PORT_LOCK(port);
815 	VTCON_UNLOCK(sc);
816 	vtcon_port_enable_intr(port);
817 	VTCON_PORT_UNLOCK(port);
818 }
819 
820 static void
821 vtcon_ctrl_port_name_event(struct vtcon_softc *sc, int id, const char *name,
822     size_t len)
823 {
824 	device_t dev;
825 	struct vtcon_softc_port *scport;
826 	struct vtcon_port *port;
827 
828 	dev = sc->vtcon_dev;
829 	scport = &sc->vtcon_ports[id];
830 
831 	/*
832 	 * The VirtIO specification says the NUL terminator is not included in
833 	 * the length, but QEMU includes it. Adjust the length if needed.
834 	 */
835 	if (name == NULL || len == 0)
836 		return;
837 	if (name[len - 1] == '\0') {
838 		len--;
839 		if (len == 0)
840 			return;
841 	}
842 
843 	VTCON_LOCK(sc);
844 	port = scport->vcsp_port;
845 	if (port == NULL) {
846 		VTCON_UNLOCK(sc);
847 		device_printf(dev, "%s: name port %d, but does not exist\n",
848 		    __func__, id);
849 		return;
850 	}
851 
852 	VTCON_PORT_LOCK(port);
853 	VTCON_UNLOCK(sc);
854 	vtcon_port_dev_alias(port, name, len);
855 	VTCON_PORT_UNLOCK(port);
856 }
857 
858 static void
859 vtcon_ctrl_process_event(struct vtcon_softc *sc,
860     struct virtio_console_control *control, void *data, size_t data_len)
861 {
862 	device_t dev;
863 	uint32_t id;
864 	uint16_t event;
865 
866 	dev = sc->vtcon_dev;
867 	id = vtcon_htog32(sc, control->id);
868 	event = vtcon_htog16(sc, control->event);
869 
870 	if (id >= sc->vtcon_max_ports) {
871 		device_printf(dev, "%s: event %d invalid port ID %d\n",
872 		    __func__, event, id);
873 		return;
874 	}
875 
876 	switch (event) {
877 	case VIRTIO_CONSOLE_PORT_ADD:
878 		vtcon_ctrl_port_add_event(sc, id);
879 		break;
880 
881 	case VIRTIO_CONSOLE_PORT_REMOVE:
882 		vtcon_ctrl_port_remove_event(sc, id);
883 		break;
884 
885 	case VIRTIO_CONSOLE_CONSOLE_PORT:
886 		vtcon_ctrl_port_console_event(sc, id);
887 		break;
888 
889 	case VIRTIO_CONSOLE_RESIZE:
890 		break;
891 
892 	case VIRTIO_CONSOLE_PORT_OPEN:
893 		vtcon_ctrl_port_open_event(sc, id);
894 		break;
895 
896 	case VIRTIO_CONSOLE_PORT_NAME:
897 		vtcon_ctrl_port_name_event(sc, id, (const char *)data, data_len);
898 		break;
899 	}
900 }
901 
902 static void
903 vtcon_ctrl_task_cb(void *xsc, int pending)
904 {
905 	struct vtcon_softc *sc;
906 	struct virtqueue *vq;
907 	struct virtio_console_control *control;
908 	void *data;
909 	size_t data_len;
910 	int detached;
911 	uint32_t len;
912 
913 	sc = xsc;
914 	vq = sc->vtcon_ctrl_rxvq;
915 
916 	VTCON_LOCK(sc);
917 
918 	while ((detached = (sc->vtcon_flags & VTCON_FLAG_DETACHED)) == 0) {
919 		control = virtqueue_dequeue(vq, &len);
920 		if (control == NULL)
921 			break;
922 
923 		if (len > sizeof(struct virtio_console_control)) {
924 			data = (void *) &control[1];
925 			data_len = len - sizeof(struct virtio_console_control);
926 		} else {
927 			data = NULL;
928 			data_len = 0;
929 		}
930 
931 		VTCON_UNLOCK(sc);
932 		vtcon_ctrl_process_event(sc, control, data, data_len);
933 		VTCON_LOCK(sc);
934 		vtcon_ctrl_event_requeue(sc, control);
935 	}
936 
937 	if (!detached) {
938 		virtqueue_notify(vq);
939 		if (virtqueue_enable_intr(vq) != 0)
940 			taskqueue_enqueue(taskqueue_thread,
941 			    &sc->vtcon_ctrl_task);
942 	}
943 
944 	VTCON_UNLOCK(sc);
945 }
946 
947 static void
948 vtcon_ctrl_event_intr(void *xsc)
949 {
950 	struct vtcon_softc *sc;
951 
952 	sc = xsc;
953 
954 	/*
955 	 * Only some events require us to potentially block, but it
956 	 * easier to just defer all event handling to the taskqueue.
957 	 */
958 	taskqueue_enqueue(taskqueue_thread, &sc->vtcon_ctrl_task);
959 }
960 
961 static void
962 vtcon_ctrl_poll(struct vtcon_softc *sc,
963     struct virtio_console_control *control)
964 {
965 	struct sglist_seg segs[2];
966 	struct sglist sg;
967 	struct virtqueue *vq;
968 	int error;
969 
970 	vq = sc->vtcon_ctrl_txvq;
971 
972 	sglist_init(&sg, 2, segs);
973 	error = sglist_append(&sg, control,
974 	    sizeof(struct virtio_console_control));
975 	KASSERT(error == 0, ("%s: error %d adding control to sglist",
976 	    __func__, error));
977 
978 	/*
979 	 * We cannot use the softc lock to serialize access to this
980 	 * virtqueue since this is called from the tty layer with the
981 	 * port lock held. Acquiring the softc would violate our lock
982 	 * ordering.
983 	 */
984 	VTCON_CTRL_TX_LOCK(sc);
985 	KASSERT(virtqueue_empty(vq),
986 	    ("%s: virtqueue is not emtpy", __func__));
987 	error = virtqueue_enqueue(vq, control, &sg, sg.sg_nseg, 0);
988 	if (error == 0) {
989 		virtqueue_notify(vq);
990 		virtqueue_poll(vq, NULL);
991 	}
992 	VTCON_CTRL_TX_UNLOCK(sc);
993 }
994 
995 static void
996 vtcon_ctrl_send_control(struct vtcon_softc *sc, uint32_t portid,
997     uint16_t event, uint16_t value)
998 {
999 	struct virtio_console_control control;
1000 
1001 	if ((sc->vtcon_flags & VTCON_FLAG_MULTIPORT) == 0)
1002 		return;
1003 
1004 	control.id = vtcon_gtoh32(sc, portid);
1005 	control.event = vtcon_gtoh16(sc, event);
1006 	control.value = vtcon_gtoh16(sc, value);
1007 
1008 	vtcon_ctrl_poll(sc, &control);
1009 }
1010 
1011 static int
1012 vtcon_port_enqueue_buf(struct vtcon_port *port, void *buf, size_t len)
1013 {
1014 	struct sglist_seg segs[2];
1015 	struct sglist sg;
1016 	struct virtqueue *vq;
1017 	int error;
1018 
1019 	vq = port->vtcport_invq;
1020 
1021 	sglist_init(&sg, 2, segs);
1022 	error = sglist_append(&sg, buf, len);
1023 	KASSERT(error == 0,
1024 	    ("%s: error %d adding buffer to sglist", __func__, error));
1025 
1026 	error = virtqueue_enqueue(vq, buf, &sg, 0, sg.sg_nseg);
1027 
1028 	return (error);
1029 }
1030 
1031 static int
1032 vtcon_port_create_buf(struct vtcon_port *port)
1033 {
1034 	void *buf;
1035 	int error;
1036 
1037 	buf = malloc(VTCON_BULK_BUFSZ, M_DEVBUF, M_ZERO | M_NOWAIT);
1038 	if (buf == NULL)
1039 		return (ENOMEM);
1040 
1041 	error = vtcon_port_enqueue_buf(port, buf, VTCON_BULK_BUFSZ);
1042 	if (error)
1043 		free(buf, M_DEVBUF);
1044 
1045 	return (error);
1046 }
1047 
1048 static void
1049 vtcon_port_requeue_buf(struct vtcon_port *port, void *buf)
1050 {
1051 	int error;
1052 
1053 	error = vtcon_port_enqueue_buf(port, buf, VTCON_BULK_BUFSZ);
1054 	KASSERT(error == 0,
1055 	    ("%s: cannot requeue input buffer %d", __func__, error));
1056 }
1057 
1058 static int
1059 vtcon_port_populate(struct vtcon_port *port)
1060 {
1061 	struct virtqueue *vq;
1062 	int nbufs, error;
1063 
1064 	vq = port->vtcport_invq;
1065 	error = ENOSPC;
1066 
1067 	for (nbufs = 0; !virtqueue_full(vq); nbufs++) {
1068 		error = vtcon_port_create_buf(port);
1069 		if (error)
1070 			break;
1071 	}
1072 
1073 	if (nbufs > 0) {
1074 		virtqueue_notify(vq);
1075 		error = 0;
1076 	}
1077 
1078 	return (error);
1079 }
1080 
1081 static void
1082 vtcon_port_destroy(struct vtcon_port *port)
1083 {
1084 
1085 	port->vtcport_sc = NULL;
1086 	port->vtcport_scport = NULL;
1087 	port->vtcport_invq = NULL;
1088 	port->vtcport_outvq = NULL;
1089 	port->vtcport_id = -1;
1090 	mtx_destroy(&port->vtcport_mtx);
1091 	free(port, M_DEVBUF);
1092 }
1093 
1094 static int
1095 vtcon_port_init_vqs(struct vtcon_port *port)
1096 {
1097 	struct vtcon_softc_port *scport;
1098 	int error;
1099 
1100 	scport = port->vtcport_scport;
1101 
1102 	port->vtcport_invq = scport->vcsp_invq;
1103 	port->vtcport_outvq = scport->vcsp_outvq;
1104 
1105 	/*
1106 	 * Free any data left over from when this virtqueue was in use by a
1107 	 * prior port. We have not yet notified the host that the port is
1108 	 * ready, so assume nothing in the virtqueue can be for us.
1109 	 */
1110 	vtcon_port_drain(port);
1111 
1112 	KASSERT(virtqueue_empty(port->vtcport_invq),
1113 	    ("%s: in virtqueue is not empty", __func__));
1114 	KASSERT(virtqueue_empty(port->vtcport_outvq),
1115 	    ("%s: out virtqueue is not empty", __func__));
1116 
1117 	error = vtcon_port_populate(port);
1118 	if (error)
1119 		return (error);
1120 
1121 	return (0);
1122 }
1123 
1124 static int
1125 vtcon_port_create(struct vtcon_softc *sc, int id)
1126 {
1127 	device_t dev;
1128 	struct vtcon_softc_port *scport;
1129 	struct vtcon_port *port;
1130 	int error;
1131 
1132 	dev = sc->vtcon_dev;
1133 	scport = &sc->vtcon_ports[id];
1134 
1135 	VTCON_ASSERT_VALID_PORTID(sc, id);
1136 	MPASS(scport->vcsp_port == NULL);
1137 
1138 	port = malloc(sizeof(struct vtcon_port), M_DEVBUF, M_NOWAIT | M_ZERO);
1139 	if (port == NULL)
1140 		return (ENOMEM);
1141 
1142 	port->vtcport_sc = sc;
1143 	port->vtcport_scport = scport;
1144 	port->vtcport_id = id;
1145 	mtx_init(&port->vtcport_mtx, "vtcpmtx", NULL, MTX_DEF);
1146 	port->vtcport_tty = tty_alloc_mutex(&vtcon_tty_class, port,
1147 	    &port->vtcport_mtx);
1148 
1149 	error = vtcon_port_init_vqs(port);
1150 	if (error) {
1151 		VTCON_PORT_LOCK(port);
1152 		vtcon_port_teardown(port);
1153 		return (error);
1154 	}
1155 
1156 	VTCON_LOCK(sc);
1157 	VTCON_PORT_LOCK(port);
1158 	scport->vcsp_port = port;
1159 	vtcon_port_enable_intr(port);
1160 	vtcon_port_submit_event(port, VIRTIO_CONSOLE_PORT_READY, 1);
1161 	VTCON_PORT_UNLOCK(port);
1162 	VTCON_UNLOCK(sc);
1163 
1164 	tty_makedev(port->vtcport_tty, NULL, "%s%r.%r", VTCON_TTY_PREFIX,
1165 	    device_get_unit(dev), id);
1166 
1167 	return (0);
1168 }
1169 
1170 static void
1171 vtcon_port_dev_alias(struct vtcon_port *port, const char *name, size_t len)
1172 {
1173 	struct vtcon_softc *sc;
1174 	struct cdev *pdev;
1175 	struct tty *tp;
1176 	int i, error;
1177 
1178 	sc = port->vtcport_sc;
1179 	tp = port->vtcport_tty;
1180 
1181 	if (port->vtcport_flags & VTCON_PORT_FLAG_ALIAS)
1182 		return;
1183 
1184 	/* Port name is UTF-8, but we can only handle ASCII. */
1185 	for (i = 0; i < len; i++) {
1186 		if (!isascii(name[i]))
1187 			return;
1188 	}
1189 
1190 	/*
1191 	 * Port name may not conform to the devfs requirements so we cannot use
1192 	 * tty_makealias() because the MAKEDEV_CHECKNAME flag must be specified.
1193 	 */
1194 	error = make_dev_alias_p(MAKEDEV_NOWAIT | MAKEDEV_CHECKNAME, &pdev,
1195 	    tp->t_dev, "%s/%*s", VTCON_TTY_ALIAS_PREFIX, (int)len, name);
1196 	if (error) {
1197 		device_printf(sc->vtcon_dev,
1198 		    "%s: cannot make dev alias (%s/%*s) error %d\n", __func__,
1199 		    VTCON_TTY_ALIAS_PREFIX, (int)len, name, error);
1200 	} else
1201 		port->vtcport_flags |= VTCON_PORT_FLAG_ALIAS;
1202 }
1203 
1204 static void
1205 vtcon_port_drain_bufs(struct virtqueue *vq)
1206 {
1207 	void *buf;
1208 	int last;
1209 
1210 	last = 0;
1211 
1212 	while ((buf = virtqueue_drain(vq, &last)) != NULL)
1213 		free(buf, M_DEVBUF);
1214 }
1215 
1216 static void
1217 vtcon_port_drain(struct vtcon_port *port)
1218 {
1219 
1220 	vtcon_port_drain_bufs(port->vtcport_invq);
1221 }
1222 
1223 static void
1224 vtcon_port_teardown(struct vtcon_port *port)
1225 {
1226 	struct tty *tp;
1227 
1228 	tp = port->vtcport_tty;
1229 
1230 	port->vtcport_flags |= VTCON_PORT_FLAG_GONE;
1231 
1232 	if (tp != NULL) {
1233 		atomic_add_int(&vtcon_pending_free, 1);
1234 		tty_rel_gone(tp);
1235 	} else
1236 		vtcon_port_destroy(port);
1237 }
1238 
1239 static void
1240 vtcon_port_change_size(struct vtcon_port *port, uint16_t cols, uint16_t rows)
1241 {
1242 	struct tty *tp;
1243 	struct winsize sz;
1244 
1245 	tp = port->vtcport_tty;
1246 
1247 	if (tp == NULL)
1248 		return;
1249 
1250 	bzero(&sz, sizeof(struct winsize));
1251 	sz.ws_col = cols;
1252 	sz.ws_row = rows;
1253 
1254 	tty_set_winsize(tp, &sz);
1255 }
1256 
1257 static void
1258 vtcon_port_update_console_size(struct vtcon_softc *sc)
1259 {
1260 	struct vtcon_port *port;
1261 	struct vtcon_softc_port *scport;
1262 	uint16_t cols, rows;
1263 
1264 	vtcon_get_console_size(sc, &cols, &rows);
1265 
1266 	/*
1267 	 * For now, assume the first (only) port is the console. Note
1268 	 * QEMU does not implement this feature yet.
1269 	 */
1270 	scport = &sc->vtcon_ports[0];
1271 
1272 	VTCON_LOCK(sc);
1273 	port = scport->vcsp_port;
1274 
1275 	if (port != NULL) {
1276 		VTCON_PORT_LOCK(port);
1277 		VTCON_UNLOCK(sc);
1278 		vtcon_port_change_size(port, cols, rows);
1279 		VTCON_PORT_UNLOCK(port);
1280 	} else
1281 		VTCON_UNLOCK(sc);
1282 }
1283 
1284 static void
1285 vtcon_port_enable_intr(struct vtcon_port *port)
1286 {
1287 
1288 	/*
1289 	 * NOTE: The out virtqueue is always polled, so its interrupt
1290 	 * kept disabled.
1291 	 */
1292 	virtqueue_enable_intr(port->vtcport_invq);
1293 }
1294 
1295 static void
1296 vtcon_port_disable_intr(struct vtcon_port *port)
1297 {
1298 
1299 	if (port->vtcport_invq != NULL)
1300 		virtqueue_disable_intr(port->vtcport_invq);
1301 	if (port->vtcport_outvq != NULL)
1302 		virtqueue_disable_intr(port->vtcport_outvq);
1303 }
1304 
1305 static void
1306 vtcon_port_in(struct vtcon_port *port)
1307 {
1308 	struct virtqueue *vq;
1309 	struct tty *tp;
1310 	char *buf;
1311 	uint32_t len;
1312 	int i, deq;
1313 
1314 	tp = port->vtcport_tty;
1315 	vq = port->vtcport_invq;
1316 
1317 again:
1318 	deq = 0;
1319 
1320 	while ((buf = virtqueue_dequeue(vq, &len)) != NULL) {
1321 		for (i = 0; i < len; i++) {
1322 #if defined(KDB)
1323 			if (port->vtcport_flags & VTCON_PORT_FLAG_CONSOLE)
1324 				kdb_alt_break(buf[i],
1325 				    &port->vtcport_alt_break_state);
1326 #endif
1327 			ttydisc_rint(tp, buf[i], 0);
1328 		}
1329 		vtcon_port_requeue_buf(port, buf);
1330 		deq++;
1331 	}
1332 	ttydisc_rint_done(tp);
1333 
1334 	if (deq > 0)
1335 		virtqueue_notify(vq);
1336 
1337 	if (virtqueue_enable_intr(vq) != 0)
1338 		goto again;
1339 }
1340 
1341 static void
1342 vtcon_port_intr(void *scportx)
1343 {
1344 	struct vtcon_softc_port *scport;
1345 	struct vtcon_softc *sc;
1346 	struct vtcon_port *port;
1347 
1348 	scport = scportx;
1349 	sc = scport->vcsp_sc;
1350 
1351 	VTCON_LOCK(sc);
1352 	port = scport->vcsp_port;
1353 	if (port == NULL) {
1354 		VTCON_UNLOCK(sc);
1355 		return;
1356 	}
1357 	VTCON_PORT_LOCK(port);
1358 	VTCON_UNLOCK(sc);
1359 	if ((port->vtcport_flags & VTCON_PORT_FLAG_GONE) == 0)
1360 		vtcon_port_in(port);
1361 	VTCON_PORT_UNLOCK(port);
1362 }
1363 
1364 static void
1365 vtcon_port_out(struct vtcon_port *port, void *buf, int bufsize)
1366 {
1367 	struct sglist_seg segs[2];
1368 	struct sglist sg;
1369 	struct virtqueue *vq;
1370 	int error;
1371 
1372 	vq = port->vtcport_outvq;
1373 	KASSERT(virtqueue_empty(vq),
1374 	    ("%s: port %p out virtqueue not emtpy", __func__, port));
1375 
1376 	sglist_init(&sg, 2, segs);
1377 	error = sglist_append(&sg, buf, bufsize);
1378 	KASSERT(error == 0, ("%s: error %d adding buffer to sglist",
1379 	    __func__, error));
1380 
1381 	error = virtqueue_enqueue(vq, buf, &sg, sg.sg_nseg, 0);
1382 	if (error == 0) {
1383 		virtqueue_notify(vq);
1384 		virtqueue_poll(vq, NULL);
1385 	}
1386 }
1387 
1388 static void
1389 vtcon_port_submit_event(struct vtcon_port *port, uint16_t event,
1390     uint16_t value)
1391 {
1392 	struct vtcon_softc *sc;
1393 
1394 	sc = port->vtcport_sc;
1395 
1396 	vtcon_ctrl_send_control(sc, port->vtcport_id, event, value);
1397 }
1398 
1399 static int
1400 vtcon_tty_open(struct tty *tp)
1401 {
1402 	struct vtcon_port *port;
1403 
1404 	port = tty_softc(tp);
1405 
1406 	if (port->vtcport_flags & VTCON_PORT_FLAG_GONE)
1407 		return (ENXIO);
1408 
1409 	vtcon_port_submit_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
1410 
1411 	return (0);
1412 }
1413 
1414 static void
1415 vtcon_tty_close(struct tty *tp)
1416 {
1417 	struct vtcon_port *port;
1418 
1419 	port = tty_softc(tp);
1420 
1421 	if (port->vtcport_flags & VTCON_PORT_FLAG_GONE)
1422 		return;
1423 
1424 	vtcon_port_submit_event(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
1425 }
1426 
1427 static void
1428 vtcon_tty_outwakeup(struct tty *tp)
1429 {
1430 	struct vtcon_port *port;
1431 	char buf[VTCON_BULK_BUFSZ];
1432 	int len;
1433 
1434 	port = tty_softc(tp);
1435 
1436 	if (port->vtcport_flags & VTCON_PORT_FLAG_GONE)
1437 		return;
1438 
1439 	while ((len = ttydisc_getc(tp, buf, sizeof(buf))) != 0)
1440 		vtcon_port_out(port, buf, len);
1441 }
1442 
1443 static void
1444 vtcon_tty_free(void *xport)
1445 {
1446 	struct vtcon_port *port;
1447 
1448 	port = xport;
1449 
1450 	vtcon_port_destroy(port);
1451 	atomic_subtract_int(&vtcon_pending_free, 1);
1452 }
1453 
1454 static void
1455 vtcon_get_console_size(struct vtcon_softc *sc, uint16_t *cols, uint16_t *rows)
1456 {
1457 	struct virtio_console_config concfg;
1458 
1459 	KASSERT(sc->vtcon_flags & VTCON_FLAG_SIZE,
1460 	    ("%s: size feature not negotiated", __func__));
1461 
1462 	vtcon_read_config(sc, &concfg);
1463 
1464 	*cols = concfg.cols;
1465 	*rows = concfg.rows;
1466 }
1467 
1468 static void
1469 vtcon_enable_interrupts(struct vtcon_softc *sc)
1470 {
1471 	struct vtcon_softc_port *scport;
1472 	struct vtcon_port *port;
1473 	int i;
1474 
1475 	VTCON_LOCK(sc);
1476 
1477 	if (sc->vtcon_flags & VTCON_FLAG_MULTIPORT)
1478 		virtqueue_enable_intr(sc->vtcon_ctrl_rxvq);
1479 
1480 	for (i = 0; i < sc->vtcon_max_ports; i++) {
1481 		scport = &sc->vtcon_ports[i];
1482 
1483 		port = scport->vcsp_port;
1484 		if (port == NULL)
1485 			continue;
1486 
1487 		VTCON_PORT_LOCK(port);
1488 		vtcon_port_enable_intr(port);
1489 		VTCON_PORT_UNLOCK(port);
1490 	}
1491 
1492 	VTCON_UNLOCK(sc);
1493 }
1494 
1495 static void
1496 vtcon_disable_interrupts(struct vtcon_softc *sc)
1497 {
1498 	struct vtcon_softc_port *scport;
1499 	struct vtcon_port *port;
1500 	int i;
1501 
1502 	VTCON_LOCK_ASSERT(sc);
1503 
1504 	if (sc->vtcon_flags & VTCON_FLAG_MULTIPORT)
1505 		virtqueue_disable_intr(sc->vtcon_ctrl_rxvq);
1506 
1507 	for (i = 0; i < sc->vtcon_max_ports; i++) {
1508 		scport = &sc->vtcon_ports[i];
1509 
1510 		port = scport->vcsp_port;
1511 		if (port == NULL)
1512 			continue;
1513 
1514 		VTCON_PORT_LOCK(port);
1515 		vtcon_port_disable_intr(port);
1516 		VTCON_PORT_UNLOCK(port);
1517 	}
1518 }
1519