xref: /freebsd/sys/dev/virtio/console/virtio_console.c (revision 96190b4fef3b4a0cc3ca0606b0c4e3e69a5e6717)
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/param.h>
30 #include <sys/ctype.h>
31 #include <sys/systm.h>
32 #include <sys/kernel.h>
33 #include <sys/malloc.h>
34 #include <sys/module.h>
35 #include <sys/kdb.h>
36 #include <sys/lock.h>
37 #include <sys/mutex.h>
38 #include <sys/sglist.h>
39 #include <sys/sysctl.h>
40 #include <sys/taskqueue.h>
41 #include <sys/queue.h>
42 
43 #include <sys/conf.h>
44 #include <sys/cons.h>
45 #include <sys/tty.h>
46 
47 #include <machine/bus.h>
48 #include <machine/resource.h>
49 #include <sys/bus.h>
50 
51 #include <dev/virtio/virtio.h>
52 #include <dev/virtio/virtqueue.h>
53 #include <dev/virtio/console/virtio_console.h>
54 
55 #include "virtio_if.h"
56 
57 #define VTCON_MAX_PORTS 32
58 #define VTCON_TTY_PREFIX "V"
59 #define VTCON_TTY_ALIAS_PREFIX "vtcon"
60 #define VTCON_BULK_BUFSZ 128
61 #define VTCON_CTRL_BUFSZ 128
62 
63 /*
64  * The buffers cannot cross more than one page boundary due to the
65  * size of the sglist segment array used.
66  */
67 CTASSERT(VTCON_BULK_BUFSZ <= PAGE_SIZE);
68 CTASSERT(VTCON_CTRL_BUFSZ <= PAGE_SIZE);
69 
70 CTASSERT(sizeof(struct virtio_console_config) <= VTCON_CTRL_BUFSZ);
71 
72 struct vtcon_softc;
73 struct vtcon_softc_port;
74 
75 struct vtcon_port {
76 	struct mtx			 vtcport_mtx;
77 	struct vtcon_softc		*vtcport_sc;
78 	struct vtcon_softc_port		*vtcport_scport;
79 	struct tty			*vtcport_tty;
80 	struct virtqueue		*vtcport_invq;
81 	struct virtqueue		*vtcport_outvq;
82 	int				 vtcport_id;
83 	int				 vtcport_flags;
84 #define VTCON_PORT_FLAG_GONE	0x01
85 #define VTCON_PORT_FLAG_CONSOLE	0x02
86 #define VTCON_PORT_FLAG_ALIAS	0x04
87 
88 #if defined(KDB)
89 	int				 vtcport_alt_break_state;
90 #endif
91 };
92 
93 #define VTCON_PORT_LOCK(_port)		mtx_lock(&(_port)->vtcport_mtx)
94 #define VTCON_PORT_UNLOCK(_port)	mtx_unlock(&(_port)->vtcport_mtx)
95 
96 struct vtcon_softc_port {
97 	struct vtcon_softc	*vcsp_sc;
98 	struct vtcon_port	*vcsp_port;
99 	struct virtqueue	*vcsp_invq;
100 	struct virtqueue	*vcsp_outvq;
101 };
102 
103 struct vtcon_softc {
104 	device_t		 vtcon_dev;
105 	struct mtx		 vtcon_mtx;
106 	uint64_t		 vtcon_features;
107 	uint32_t		 vtcon_max_ports;
108 	uint32_t		 vtcon_flags;
109 #define VTCON_FLAG_DETACHED	0x01
110 #define VTCON_FLAG_SIZE		0x02
111 #define VTCON_FLAG_MULTIPORT	0x04
112 
113 	/*
114 	 * Ports can be added and removed during runtime, but we have
115 	 * to allocate all the virtqueues during attach. This array is
116 	 * indexed by the port ID.
117 	 */
118 	struct vtcon_softc_port	*vtcon_ports;
119 
120 	struct task		 vtcon_ctrl_task;
121 	struct virtqueue	*vtcon_ctrl_rxvq;
122 	struct virtqueue	*vtcon_ctrl_txvq;
123 	struct mtx		 vtcon_ctrl_tx_mtx;
124 };
125 
126 #define VTCON_LOCK(_sc)			mtx_lock(&(_sc)->vtcon_mtx)
127 #define VTCON_UNLOCK(_sc)		mtx_unlock(&(_sc)->vtcon_mtx)
128 #define VTCON_LOCK_ASSERT(_sc)		\
129     mtx_assert(&(_sc)->vtcon_mtx, MA_OWNED)
130 #define VTCON_LOCK_ASSERT_NOTOWNED(_sc)	\
131     mtx_assert(&(_sc)->vtcon_mtx, MA_NOTOWNED)
132 
133 #define VTCON_CTRL_TX_LOCK(_sc)		mtx_lock(&(_sc)->vtcon_ctrl_tx_mtx)
134 #define VTCON_CTRL_TX_UNLOCK(_sc)	mtx_unlock(&(_sc)->vtcon_ctrl_tx_mtx)
135 
136 #define VTCON_ASSERT_VALID_PORTID(_sc, _id)			\
137     KASSERT((_id) >= 0 && (_id) < (_sc)->vtcon_max_ports,	\
138         ("%s: port ID %d out of range", __func__, _id))
139 
140 #define VTCON_FEATURES  VIRTIO_CONSOLE_F_MULTIPORT
141 
142 static struct virtio_feature_desc vtcon_feature_desc[] = {
143 	{ VIRTIO_CONSOLE_F_SIZE,	"ConsoleSize"	},
144 	{ VIRTIO_CONSOLE_F_MULTIPORT,	"MultiplePorts"	},
145 	{ VIRTIO_CONSOLE_F_EMERG_WRITE,	"EmergencyWrite" },
146 	{ 0, NULL }
147 };
148 
149 static int	 vtcon_modevent(module_t, int, void *);
150 static void	 vtcon_drain_all(void);
151 
152 static int	 vtcon_probe(device_t);
153 static int	 vtcon_attach(device_t);
154 static int	 vtcon_detach(device_t);
155 static int	 vtcon_config_change(device_t);
156 
157 static int	 vtcon_setup_features(struct vtcon_softc *);
158 static int	 vtcon_negotiate_features(struct vtcon_softc *);
159 static int	 vtcon_alloc_scports(struct vtcon_softc *);
160 static int	 vtcon_alloc_virtqueues(struct vtcon_softc *);
161 static void	 vtcon_read_config(struct vtcon_softc *,
162 		     struct virtio_console_config *);
163 
164 static void	 vtcon_determine_max_ports(struct vtcon_softc *,
165 		     struct virtio_console_config *);
166 static void	 vtcon_destroy_ports(struct vtcon_softc *);
167 static void	 vtcon_stop(struct vtcon_softc *);
168 
169 static int	 vtcon_ctrl_event_enqueue(struct vtcon_softc *,
170 		     struct virtio_console_control *);
171 static int	 vtcon_ctrl_event_create(struct vtcon_softc *);
172 static void	 vtcon_ctrl_event_requeue(struct vtcon_softc *,
173 		     struct virtio_console_control *);
174 static int	 vtcon_ctrl_event_populate(struct vtcon_softc *);
175 static void	 vtcon_ctrl_event_drain(struct vtcon_softc *);
176 static int	 vtcon_ctrl_init(struct vtcon_softc *);
177 static void	 vtcon_ctrl_deinit(struct vtcon_softc *);
178 static void	 vtcon_ctrl_port_add_event(struct vtcon_softc *, int);
179 static void	 vtcon_ctrl_port_remove_event(struct vtcon_softc *, int);
180 static void	 vtcon_ctrl_port_console_event(struct vtcon_softc *, int);
181 static void	 vtcon_ctrl_port_open_event(struct vtcon_softc *, int);
182 static void	 vtcon_ctrl_port_name_event(struct vtcon_softc *, int,
183 		     const char *, size_t);
184 static void	 vtcon_ctrl_process_event(struct vtcon_softc *,
185 		     struct virtio_console_control *, void *, size_t);
186 static void	 vtcon_ctrl_task_cb(void *, int);
187 static void	 vtcon_ctrl_event_intr(void *);
188 static void	 vtcon_ctrl_poll(struct vtcon_softc *,
189 		     struct virtio_console_control *control);
190 static void	 vtcon_ctrl_send_control(struct vtcon_softc *, uint32_t,
191 		     uint16_t, uint16_t);
192 
193 static int	 vtcon_port_enqueue_buf(struct vtcon_port *, void *, size_t);
194 static int	 vtcon_port_create_buf(struct vtcon_port *);
195 static void	 vtcon_port_requeue_buf(struct vtcon_port *, void *);
196 static int	 vtcon_port_populate(struct vtcon_port *);
197 static void	 vtcon_port_destroy(struct vtcon_port *);
198 static int	 vtcon_port_create(struct vtcon_softc *, int);
199 static void	 vtcon_port_dev_alias(struct vtcon_port *, const char *,
200 		     size_t);
201 static void	 vtcon_port_drain_bufs(struct virtqueue *);
202 static void	 vtcon_port_drain(struct vtcon_port *);
203 static void	 vtcon_port_teardown(struct vtcon_port *);
204 static void	 vtcon_port_change_size(struct vtcon_port *, uint16_t,
205 		     uint16_t);
206 static void	 vtcon_port_update_console_size(struct vtcon_softc *);
207 static void	 vtcon_port_enable_intr(struct vtcon_port *);
208 static void	 vtcon_port_disable_intr(struct vtcon_port *);
209 static void	 vtcon_port_in(struct vtcon_port *);
210 static void	 vtcon_port_intr(void *);
211 static void	 vtcon_port_out(struct vtcon_port *, void *, int);
212 static void	 vtcon_port_submit_event(struct vtcon_port *, uint16_t,
213 		     uint16_t);
214 
215 static int	 vtcon_tty_open(struct tty *);
216 static void	 vtcon_tty_close(struct tty *);
217 static void	 vtcon_tty_outwakeup(struct tty *);
218 static void	 vtcon_tty_free(void *);
219 
220 static void	 vtcon_get_console_size(struct vtcon_softc *, uint16_t *,
221 		     uint16_t *);
222 
223 static void	 vtcon_enable_interrupts(struct vtcon_softc *);
224 static void	 vtcon_disable_interrupts(struct vtcon_softc *);
225 
226 #define vtcon_modern(_sc) (((_sc)->vtcon_features & VIRTIO_F_VERSION_1) != 0)
227 #define vtcon_htog16(_sc, _val)	virtio_htog16(vtcon_modern(_sc), _val)
228 #define vtcon_htog32(_sc, _val)	virtio_htog32(vtcon_modern(_sc), _val)
229 #define vtcon_htog64(_sc, _val)	virtio_htog64(vtcon_modern(_sc), _val)
230 #define vtcon_gtoh16(_sc, _val)	virtio_gtoh16(vtcon_modern(_sc), _val)
231 #define vtcon_gtoh32(_sc, _val)	virtio_gtoh32(vtcon_modern(_sc), _val)
232 #define vtcon_gtoh64(_sc, _val)	virtio_gtoh64(vtcon_modern(_sc), _val)
233 
234 static int	 vtcon_pending_free;
235 
236 static struct ttydevsw vtcon_tty_class = {
237 	.tsw_flags	= 0,
238 	.tsw_open	= vtcon_tty_open,
239 	.tsw_close	= vtcon_tty_close,
240 	.tsw_outwakeup	= vtcon_tty_outwakeup,
241 	.tsw_free	= vtcon_tty_free,
242 };
243 
244 static device_method_t vtcon_methods[] = {
245 	/* Device methods. */
246 	DEVMETHOD(device_probe,		vtcon_probe),
247 	DEVMETHOD(device_attach,	vtcon_attach),
248 	DEVMETHOD(device_detach,	vtcon_detach),
249 
250 	/* VirtIO methods. */
251 	DEVMETHOD(virtio_config_change,	vtcon_config_change),
252 
253 	DEVMETHOD_END
254 };
255 
256 static driver_t vtcon_driver = {
257 	"vtcon",
258 	vtcon_methods,
259 	sizeof(struct vtcon_softc)
260 };
261 
262 VIRTIO_DRIVER_MODULE(virtio_console, vtcon_driver, vtcon_modevent, NULL);
263 MODULE_VERSION(virtio_console, 1);
264 MODULE_DEPEND(virtio_console, virtio, 1, 1, 1);
265 
266 VIRTIO_SIMPLE_PNPINFO(virtio_console, VIRTIO_ID_CONSOLE,
267     "VirtIO Console Adapter");
268 
269 static int
270 vtcon_modevent(module_t mod, int type, void *unused)
271 {
272 	int error;
273 
274 	switch (type) {
275 	case MOD_LOAD:
276 		error = 0;
277 		break;
278 	case MOD_QUIESCE:
279 		error = 0;
280 		break;
281 	case MOD_UNLOAD:
282 		vtcon_drain_all();
283 		error = 0;
284 		break;
285 	case MOD_SHUTDOWN:
286 		error = 0;
287 		break;
288 	default:
289 		error = EOPNOTSUPP;
290 		break;
291 	}
292 
293 	return (error);
294 }
295 
296 static void
297 vtcon_drain_all(void)
298 {
299 	int first;
300 
301 	for (first = 1; vtcon_pending_free != 0; first = 0) {
302 		if (first != 0) {
303 			printf("virtio_console: Waiting for all detached TTY "
304 			    "devices to have open fds closed.\n");
305 		}
306 		pause("vtcondra", hz);
307 	}
308 }
309 
310 static int
311 vtcon_probe(device_t dev)
312 {
313 	return (VIRTIO_SIMPLE_PROBE(dev, virtio_console));
314 }
315 
316 static int
317 vtcon_attach(device_t dev)
318 {
319 	struct vtcon_softc *sc;
320 	struct virtio_console_config concfg;
321 	int error;
322 
323 	sc = device_get_softc(dev);
324 	sc->vtcon_dev = dev;
325 	virtio_set_feature_desc(dev, vtcon_feature_desc);
326 
327 	mtx_init(&sc->vtcon_mtx, "vtconmtx", NULL, MTX_DEF);
328 	mtx_init(&sc->vtcon_ctrl_tx_mtx, "vtconctrlmtx", NULL, MTX_DEF);
329 
330 	error = vtcon_setup_features(sc);
331 	if (error) {
332 		device_printf(dev, "cannot setup features\n");
333 		goto fail;
334 	}
335 
336 	vtcon_read_config(sc, &concfg);
337 	vtcon_determine_max_ports(sc, &concfg);
338 
339 	error = vtcon_alloc_scports(sc);
340 	if (error) {
341 		device_printf(dev, "cannot allocate softc port structures\n");
342 		goto fail;
343 	}
344 
345 	error = vtcon_alloc_virtqueues(sc);
346 	if (error) {
347 		device_printf(dev, "cannot allocate virtqueues\n");
348 		goto fail;
349 	}
350 
351 	if (sc->vtcon_flags & VTCON_FLAG_MULTIPORT) {
352 		TASK_INIT(&sc->vtcon_ctrl_task, 0, vtcon_ctrl_task_cb, sc);
353 		error = vtcon_ctrl_init(sc);
354 		if (error)
355 			goto fail;
356 	} else {
357 		error = vtcon_port_create(sc, 0);
358 		if (error)
359 			goto fail;
360 		if (sc->vtcon_flags & VTCON_FLAG_SIZE)
361 			vtcon_port_update_console_size(sc);
362 	}
363 
364 	error = virtio_setup_intr(dev, INTR_TYPE_TTY);
365 	if (error) {
366 		device_printf(dev, "cannot setup virtqueue interrupts\n");
367 		goto fail;
368 	}
369 
370 	vtcon_enable_interrupts(sc);
371 
372 	vtcon_ctrl_send_control(sc, VIRTIO_CONSOLE_BAD_ID,
373 	    VIRTIO_CONSOLE_DEVICE_READY, 1);
374 
375 fail:
376 	if (error)
377 		vtcon_detach(dev);
378 
379 	return (error);
380 }
381 
382 static int
383 vtcon_detach(device_t dev)
384 {
385 	struct vtcon_softc *sc;
386 
387 	sc = device_get_softc(dev);
388 
389 	VTCON_LOCK(sc);
390 	sc->vtcon_flags |= VTCON_FLAG_DETACHED;
391 	if (device_is_attached(dev))
392 		vtcon_stop(sc);
393 	VTCON_UNLOCK(sc);
394 
395 	if (sc->vtcon_flags & VTCON_FLAG_MULTIPORT) {
396 		taskqueue_drain(taskqueue_thread, &sc->vtcon_ctrl_task);
397 		vtcon_ctrl_deinit(sc);
398 	}
399 
400 	vtcon_destroy_ports(sc);
401 	mtx_destroy(&sc->vtcon_mtx);
402 	mtx_destroy(&sc->vtcon_ctrl_tx_mtx);
403 
404 	return (0);
405 }
406 
407 static int
408 vtcon_config_change(device_t dev)
409 {
410 	struct vtcon_softc *sc;
411 
412 	sc = device_get_softc(dev);
413 
414 	/*
415 	 * When the multiport feature is negotiated, all configuration
416 	 * changes are done through control virtqueue events.
417 	 */
418 	if ((sc->vtcon_flags & VTCON_FLAG_MULTIPORT) == 0) {
419 		if (sc->vtcon_flags & VTCON_FLAG_SIZE)
420 			vtcon_port_update_console_size(sc);
421 	}
422 
423 	return (0);
424 }
425 
426 static int
427 vtcon_negotiate_features(struct vtcon_softc *sc)
428 {
429 	device_t dev;
430 	uint64_t features;
431 
432 	dev = sc->vtcon_dev;
433 	features = VTCON_FEATURES;
434 
435 	sc->vtcon_features = virtio_negotiate_features(dev, features);
436 	return (virtio_finalize_features(dev));
437 }
438 
439 static int
440 vtcon_setup_features(struct vtcon_softc *sc)
441 {
442 	device_t dev;
443 	int error;
444 
445 	dev = sc->vtcon_dev;
446 
447 	error = vtcon_negotiate_features(sc);
448 	if (error)
449 		return (error);
450 
451 	if (virtio_with_feature(dev, VIRTIO_CONSOLE_F_SIZE))
452 		sc->vtcon_flags |= VTCON_FLAG_SIZE;
453 	if (virtio_with_feature(dev, VIRTIO_CONSOLE_F_MULTIPORT))
454 		sc->vtcon_flags |= VTCON_FLAG_MULTIPORT;
455 
456 	return (0);
457 }
458 
459 #define VTCON_GET_CONFIG(_dev, _feature, _field, _cfg)			\
460 	if (virtio_with_feature(_dev, _feature)) {			\
461 		virtio_read_device_config(_dev,				\
462 		    offsetof(struct virtio_console_config, _field),	\
463 		    &(_cfg)->_field, sizeof((_cfg)->_field));		\
464 	}
465 
466 static void
467 vtcon_read_config(struct vtcon_softc *sc, struct virtio_console_config *concfg)
468 {
469 	device_t dev;
470 
471 	dev = sc->vtcon_dev;
472 
473 	bzero(concfg, sizeof(struct virtio_console_config));
474 
475 	VTCON_GET_CONFIG(dev, VIRTIO_CONSOLE_F_SIZE, cols, concfg);
476 	VTCON_GET_CONFIG(dev, VIRTIO_CONSOLE_F_SIZE, rows, concfg);
477 	VTCON_GET_CONFIG(dev, VIRTIO_CONSOLE_F_MULTIPORT, max_nr_ports, concfg);
478 }
479 
480 #undef VTCON_GET_CONFIG
481 
482 static int
483 vtcon_alloc_scports(struct vtcon_softc *sc)
484 {
485 	struct vtcon_softc_port *scport;
486 	int max, i;
487 
488 	max = sc->vtcon_max_ports;
489 
490 	sc->vtcon_ports = malloc(sizeof(struct vtcon_softc_port) * max,
491 	    M_DEVBUF, M_NOWAIT | M_ZERO);
492 	if (sc->vtcon_ports == NULL)
493 		return (ENOMEM);
494 
495 	for (i = 0; i < max; i++) {
496 		scport = &sc->vtcon_ports[i];
497 		scport->vcsp_sc = sc;
498 	}
499 
500 	return (0);
501 }
502 
503 static int
504 vtcon_alloc_virtqueues(struct vtcon_softc *sc)
505 {
506 	device_t dev;
507 	struct vq_alloc_info *info;
508 	struct vtcon_softc_port *scport;
509 	int i, idx, portidx, nvqs, error;
510 
511 	dev = sc->vtcon_dev;
512 
513 	nvqs = sc->vtcon_max_ports * 2;
514 	if (sc->vtcon_flags & VTCON_FLAG_MULTIPORT)
515 		nvqs += 2;
516 
517 	info = malloc(sizeof(struct vq_alloc_info) * nvqs, M_TEMP, M_NOWAIT);
518 	if (info == NULL)
519 		return (ENOMEM);
520 
521 	for (i = 0, idx = 0, portidx = 0; i < nvqs / 2; i++, idx += 2) {
522 		if (i == 1) {
523 			/* The control virtqueues are after the first port. */
524 			VQ_ALLOC_INFO_INIT(&info[idx], 0,
525 			    vtcon_ctrl_event_intr, sc, &sc->vtcon_ctrl_rxvq,
526 			    "%s-control rx", device_get_nameunit(dev));
527 			VQ_ALLOC_INFO_INIT(&info[idx+1], 0,
528 			    NULL, sc, &sc->vtcon_ctrl_txvq,
529 			    "%s-control tx", device_get_nameunit(dev));
530 			continue;
531 		}
532 
533 		scport = &sc->vtcon_ports[portidx];
534 
535 		VQ_ALLOC_INFO_INIT(&info[idx], 0, vtcon_port_intr,
536 		    scport, &scport->vcsp_invq, "%s-port%d in",
537 		    device_get_nameunit(dev), i);
538 		VQ_ALLOC_INFO_INIT(&info[idx+1], 0, NULL,
539 		    NULL, &scport->vcsp_outvq, "%s-port%d out",
540 		    device_get_nameunit(dev), i);
541 
542 		portidx++;
543 	}
544 
545 	error = virtio_alloc_virtqueues(dev, nvqs, info);
546 	free(info, M_TEMP);
547 
548 	return (error);
549 }
550 
551 static void
552 vtcon_determine_max_ports(struct vtcon_softc *sc,
553     struct virtio_console_config *concfg)
554 {
555 
556 	if (sc->vtcon_flags & VTCON_FLAG_MULTIPORT) {
557 		sc->vtcon_max_ports =
558 		    min(concfg->max_nr_ports, VTCON_MAX_PORTS);
559 		if (sc->vtcon_max_ports == 0)
560 			sc->vtcon_max_ports = 1;
561 	} else
562 		sc->vtcon_max_ports = 1;
563 }
564 
565 static void
566 vtcon_destroy_ports(struct vtcon_softc *sc)
567 {
568 	struct vtcon_softc_port *scport;
569 	struct vtcon_port *port;
570 	struct virtqueue *vq;
571 	int i;
572 
573 	if (sc->vtcon_ports == NULL)
574 		return;
575 
576 	VTCON_LOCK(sc);
577 	for (i = 0; i < sc->vtcon_max_ports; i++) {
578 		scport = &sc->vtcon_ports[i];
579 
580 		port = scport->vcsp_port;
581 		if (port != NULL) {
582 			scport->vcsp_port = NULL;
583 			VTCON_PORT_LOCK(port);
584 			VTCON_UNLOCK(sc);
585 			vtcon_port_teardown(port);
586 			VTCON_LOCK(sc);
587 		}
588 
589 		vq = scport->vcsp_invq;
590 		if (vq != NULL)
591 			vtcon_port_drain_bufs(vq);
592 	}
593 	VTCON_UNLOCK(sc);
594 
595 	free(sc->vtcon_ports, M_DEVBUF);
596 	sc->vtcon_ports = NULL;
597 }
598 
599 static void
600 vtcon_stop(struct vtcon_softc *sc)
601 {
602 
603 	vtcon_disable_interrupts(sc);
604 	virtio_stop(sc->vtcon_dev);
605 }
606 
607 static int
608 vtcon_ctrl_event_enqueue(struct vtcon_softc *sc,
609     struct virtio_console_control *control)
610 {
611 	struct sglist_seg segs[2];
612 	struct sglist sg;
613 	struct virtqueue *vq;
614 	int error __diagused;
615 
616 	vq = sc->vtcon_ctrl_rxvq;
617 
618 	sglist_init(&sg, 2, segs);
619 	error = sglist_append(&sg, control, VTCON_CTRL_BUFSZ);
620 	KASSERT(error == 0, ("%s: error %d adding control to sglist",
621 	    __func__, error));
622 
623 	return (virtqueue_enqueue(vq, control, &sg, 0, sg.sg_nseg));
624 }
625 
626 static int
627 vtcon_ctrl_event_create(struct vtcon_softc *sc)
628 {
629 	struct virtio_console_control *control;
630 	int error;
631 
632 	control = malloc(VTCON_CTRL_BUFSZ, M_DEVBUF, M_ZERO | M_NOWAIT);
633 	if (control == NULL)
634 		return (ENOMEM);
635 
636 	error = vtcon_ctrl_event_enqueue(sc, control);
637 	if (error)
638 		free(control, M_DEVBUF);
639 
640 	return (error);
641 }
642 
643 static void
644 vtcon_ctrl_event_requeue(struct vtcon_softc *sc,
645     struct virtio_console_control *control)
646 {
647 	int error __diagused;
648 
649 	bzero(control, VTCON_CTRL_BUFSZ);
650 
651 	error = vtcon_ctrl_event_enqueue(sc, control);
652 	KASSERT(error == 0,
653 	    ("%s: cannot requeue control buffer %d", __func__, error));
654 }
655 
656 static int
657 vtcon_ctrl_event_populate(struct vtcon_softc *sc)
658 {
659 	struct virtqueue *vq;
660 	int nbufs, error;
661 
662 	vq = sc->vtcon_ctrl_rxvq;
663 	error = ENOSPC;
664 
665 	for (nbufs = 0; !virtqueue_full(vq); nbufs++) {
666 		error = vtcon_ctrl_event_create(sc);
667 		if (error)
668 			break;
669 	}
670 
671 	if (nbufs > 0) {
672 		virtqueue_notify(vq);
673 		error = 0;
674 	}
675 
676 	return (error);
677 }
678 
679 static void
680 vtcon_ctrl_event_drain(struct vtcon_softc *sc)
681 {
682 	struct virtio_console_control *control;
683 	struct virtqueue *vq;
684 	int last;
685 
686 	vq = sc->vtcon_ctrl_rxvq;
687 	last = 0;
688 
689 	if (vq == NULL)
690 		return;
691 
692 	VTCON_LOCK(sc);
693 	while ((control = virtqueue_drain(vq, &last)) != NULL)
694 		free(control, M_DEVBUF);
695 	VTCON_UNLOCK(sc);
696 }
697 
698 static int
699 vtcon_ctrl_init(struct vtcon_softc *sc)
700 {
701 	int error;
702 
703 	error = vtcon_ctrl_event_populate(sc);
704 
705 	return (error);
706 }
707 
708 static void
709 vtcon_ctrl_deinit(struct vtcon_softc *sc)
710 {
711 
712 	vtcon_ctrl_event_drain(sc);
713 }
714 
715 static void
716 vtcon_ctrl_port_add_event(struct vtcon_softc *sc, int id)
717 {
718 	device_t dev;
719 	int error;
720 
721 	dev = sc->vtcon_dev;
722 
723 	/* This single thread only way for ports to be created. */
724 	if (sc->vtcon_ports[id].vcsp_port != NULL) {
725 		device_printf(dev, "%s: adding port %d, but already exists\n",
726 		    __func__, id);
727 		return;
728 	}
729 
730 	error = vtcon_port_create(sc, id);
731 	if (error) {
732 		device_printf(dev, "%s: cannot create port %d: %d\n",
733 		    __func__, id, error);
734 		vtcon_ctrl_send_control(sc, id, VIRTIO_CONSOLE_PORT_READY, 0);
735 		return;
736 	}
737 }
738 
739 static void
740 vtcon_ctrl_port_remove_event(struct vtcon_softc *sc, int id)
741 {
742 	device_t dev;
743 	struct vtcon_softc_port *scport;
744 	struct vtcon_port *port;
745 
746 	dev = sc->vtcon_dev;
747 	scport = &sc->vtcon_ports[id];
748 
749 	VTCON_LOCK(sc);
750 	port = scport->vcsp_port;
751 	if (port == NULL) {
752 		VTCON_UNLOCK(sc);
753 		device_printf(dev, "%s: remove port %d, but does not exist\n",
754 		    __func__, id);
755 		return;
756 	}
757 
758 	scport->vcsp_port = NULL;
759 	VTCON_PORT_LOCK(port);
760 	VTCON_UNLOCK(sc);
761 	vtcon_port_teardown(port);
762 }
763 
764 static void
765 vtcon_ctrl_port_console_event(struct vtcon_softc *sc, int id)
766 {
767 	device_t dev;
768 	struct vtcon_softc_port *scport;
769 	struct vtcon_port *port;
770 
771 	dev = sc->vtcon_dev;
772 	scport = &sc->vtcon_ports[id];
773 
774 	VTCON_LOCK(sc);
775 	port = scport->vcsp_port;
776 	if (port == NULL) {
777 		VTCON_UNLOCK(sc);
778 		device_printf(dev, "%s: console port %d, but does not exist\n",
779 		    __func__, id);
780 		return;
781 	}
782 
783 	VTCON_PORT_LOCK(port);
784 	VTCON_UNLOCK(sc);
785 	port->vtcport_flags |= VTCON_PORT_FLAG_CONSOLE;
786 	vtcon_port_submit_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
787 	VTCON_PORT_UNLOCK(port);
788 }
789 
790 static void
791 vtcon_ctrl_port_open_event(struct vtcon_softc *sc, int id)
792 {
793 	device_t dev;
794 	struct vtcon_softc_port *scport;
795 	struct vtcon_port *port;
796 
797 	dev = sc->vtcon_dev;
798 	scport = &sc->vtcon_ports[id];
799 
800 	VTCON_LOCK(sc);
801 	port = scport->vcsp_port;
802 	if (port == NULL) {
803 		VTCON_UNLOCK(sc);
804 		device_printf(dev, "%s: open port %d, but does not exist\n",
805 		    __func__, id);
806 		return;
807 	}
808 
809 	VTCON_PORT_LOCK(port);
810 	VTCON_UNLOCK(sc);
811 	vtcon_port_enable_intr(port);
812 	VTCON_PORT_UNLOCK(port);
813 }
814 
815 static void
816 vtcon_ctrl_port_name_event(struct vtcon_softc *sc, int id, const char *name,
817     size_t len)
818 {
819 	device_t dev;
820 	struct vtcon_softc_port *scport;
821 	struct vtcon_port *port;
822 
823 	dev = sc->vtcon_dev;
824 	scport = &sc->vtcon_ports[id];
825 
826 	/*
827 	 * The VirtIO specification says the NUL terminator is not included in
828 	 * the length, but QEMU includes it. Adjust the length if needed.
829 	 */
830 	if (name == NULL || len == 0)
831 		return;
832 	if (name[len - 1] == '\0') {
833 		len--;
834 		if (len == 0)
835 			return;
836 	}
837 
838 	VTCON_LOCK(sc);
839 	port = scport->vcsp_port;
840 	if (port == NULL) {
841 		VTCON_UNLOCK(sc);
842 		device_printf(dev, "%s: name port %d, but does not exist\n",
843 		    __func__, id);
844 		return;
845 	}
846 
847 	VTCON_PORT_LOCK(port);
848 	VTCON_UNLOCK(sc);
849 	vtcon_port_dev_alias(port, name, len);
850 	VTCON_PORT_UNLOCK(port);
851 }
852 
853 static void
854 vtcon_ctrl_process_event(struct vtcon_softc *sc,
855     struct virtio_console_control *control, void *data, size_t data_len)
856 {
857 	device_t dev;
858 	uint32_t id;
859 	uint16_t event;
860 
861 	dev = sc->vtcon_dev;
862 	id = vtcon_htog32(sc, control->id);
863 	event = vtcon_htog16(sc, control->event);
864 
865 	if (id >= sc->vtcon_max_ports) {
866 		device_printf(dev, "%s: event %d invalid port ID %d\n",
867 		    __func__, event, id);
868 		return;
869 	}
870 
871 	switch (event) {
872 	case VIRTIO_CONSOLE_PORT_ADD:
873 		vtcon_ctrl_port_add_event(sc, id);
874 		break;
875 
876 	case VIRTIO_CONSOLE_PORT_REMOVE:
877 		vtcon_ctrl_port_remove_event(sc, id);
878 		break;
879 
880 	case VIRTIO_CONSOLE_CONSOLE_PORT:
881 		vtcon_ctrl_port_console_event(sc, id);
882 		break;
883 
884 	case VIRTIO_CONSOLE_RESIZE:
885 		break;
886 
887 	case VIRTIO_CONSOLE_PORT_OPEN:
888 		vtcon_ctrl_port_open_event(sc, id);
889 		break;
890 
891 	case VIRTIO_CONSOLE_PORT_NAME:
892 		vtcon_ctrl_port_name_event(sc, id, (const char *)data, data_len);
893 		break;
894 	}
895 }
896 
897 static void
898 vtcon_ctrl_task_cb(void *xsc, int pending)
899 {
900 	struct vtcon_softc *sc;
901 	struct virtqueue *vq;
902 	struct virtio_console_control *control;
903 	void *data;
904 	size_t data_len;
905 	int detached;
906 	uint32_t len;
907 
908 	sc = xsc;
909 	vq = sc->vtcon_ctrl_rxvq;
910 
911 	VTCON_LOCK(sc);
912 
913 	while ((detached = (sc->vtcon_flags & VTCON_FLAG_DETACHED)) == 0) {
914 		control = virtqueue_dequeue(vq, &len);
915 		if (control == NULL)
916 			break;
917 
918 		if (len > sizeof(struct virtio_console_control)) {
919 			data = (void *) &control[1];
920 			data_len = len - sizeof(struct virtio_console_control);
921 		} else {
922 			data = NULL;
923 			data_len = 0;
924 		}
925 
926 		VTCON_UNLOCK(sc);
927 		vtcon_ctrl_process_event(sc, control, data, data_len);
928 		VTCON_LOCK(sc);
929 		vtcon_ctrl_event_requeue(sc, control);
930 	}
931 
932 	if (!detached) {
933 		virtqueue_notify(vq);
934 		if (virtqueue_enable_intr(vq) != 0)
935 			taskqueue_enqueue(taskqueue_thread,
936 			    &sc->vtcon_ctrl_task);
937 	}
938 
939 	VTCON_UNLOCK(sc);
940 }
941 
942 static void
943 vtcon_ctrl_event_intr(void *xsc)
944 {
945 	struct vtcon_softc *sc;
946 
947 	sc = xsc;
948 
949 	/*
950 	 * Only some events require us to potentially block, but it
951 	 * easier to just defer all event handling to the taskqueue.
952 	 */
953 	taskqueue_enqueue(taskqueue_thread, &sc->vtcon_ctrl_task);
954 }
955 
956 static void
957 vtcon_ctrl_poll(struct vtcon_softc *sc,
958     struct virtio_console_control *control)
959 {
960 	struct sglist_seg segs[2];
961 	struct sglist sg;
962 	struct virtqueue *vq;
963 	int error;
964 
965 	vq = sc->vtcon_ctrl_txvq;
966 
967 	sglist_init(&sg, 2, segs);
968 	error = sglist_append(&sg, control,
969 	    sizeof(struct virtio_console_control));
970 	KASSERT(error == 0, ("%s: error %d adding control to sglist",
971 	    __func__, error));
972 
973 	/*
974 	 * We cannot use the softc lock to serialize access to this
975 	 * virtqueue since this is called from the tty layer with the
976 	 * port lock held. Acquiring the softc would violate our lock
977 	 * ordering.
978 	 */
979 	VTCON_CTRL_TX_LOCK(sc);
980 	KASSERT(virtqueue_empty(vq),
981 	    ("%s: virtqueue is not empty", __func__));
982 	error = virtqueue_enqueue(vq, control, &sg, sg.sg_nseg, 0);
983 	if (error == 0) {
984 		virtqueue_notify(vq);
985 		virtqueue_poll(vq, NULL);
986 	}
987 	VTCON_CTRL_TX_UNLOCK(sc);
988 }
989 
990 static void
991 vtcon_ctrl_send_control(struct vtcon_softc *sc, uint32_t portid,
992     uint16_t event, uint16_t value)
993 {
994 	struct virtio_console_control control;
995 
996 	if ((sc->vtcon_flags & VTCON_FLAG_MULTIPORT) == 0)
997 		return;
998 
999 	control.id = vtcon_gtoh32(sc, portid);
1000 	control.event = vtcon_gtoh16(sc, event);
1001 	control.value = vtcon_gtoh16(sc, value);
1002 
1003 	vtcon_ctrl_poll(sc, &control);
1004 }
1005 
1006 static int
1007 vtcon_port_enqueue_buf(struct vtcon_port *port, void *buf, size_t len)
1008 {
1009 	struct sglist_seg segs[2];
1010 	struct sglist sg;
1011 	struct virtqueue *vq;
1012 	int error;
1013 
1014 	vq = port->vtcport_invq;
1015 
1016 	sglist_init(&sg, 2, segs);
1017 	error = sglist_append(&sg, buf, len);
1018 	KASSERT(error == 0,
1019 	    ("%s: error %d adding buffer to sglist", __func__, error));
1020 
1021 	error = virtqueue_enqueue(vq, buf, &sg, 0, sg.sg_nseg);
1022 
1023 	return (error);
1024 }
1025 
1026 static int
1027 vtcon_port_create_buf(struct vtcon_port *port)
1028 {
1029 	void *buf;
1030 	int error;
1031 
1032 	buf = malloc(VTCON_BULK_BUFSZ, M_DEVBUF, M_ZERO | M_NOWAIT);
1033 	if (buf == NULL)
1034 		return (ENOMEM);
1035 
1036 	error = vtcon_port_enqueue_buf(port, buf, VTCON_BULK_BUFSZ);
1037 	if (error)
1038 		free(buf, M_DEVBUF);
1039 
1040 	return (error);
1041 }
1042 
1043 static void
1044 vtcon_port_requeue_buf(struct vtcon_port *port, void *buf)
1045 {
1046 	int error __diagused;
1047 
1048 	error = vtcon_port_enqueue_buf(port, buf, VTCON_BULK_BUFSZ);
1049 	KASSERT(error == 0,
1050 	    ("%s: cannot requeue input buffer %d", __func__, error));
1051 }
1052 
1053 static int
1054 vtcon_port_populate(struct vtcon_port *port)
1055 {
1056 	struct virtqueue *vq;
1057 	int nbufs, error;
1058 
1059 	vq = port->vtcport_invq;
1060 	error = ENOSPC;
1061 
1062 	for (nbufs = 0; !virtqueue_full(vq); nbufs++) {
1063 		error = vtcon_port_create_buf(port);
1064 		if (error)
1065 			break;
1066 	}
1067 
1068 	if (nbufs > 0) {
1069 		virtqueue_notify(vq);
1070 		error = 0;
1071 	}
1072 
1073 	return (error);
1074 }
1075 
1076 static void
1077 vtcon_port_destroy(struct vtcon_port *port)
1078 {
1079 
1080 	port->vtcport_sc = NULL;
1081 	port->vtcport_scport = NULL;
1082 	port->vtcport_invq = NULL;
1083 	port->vtcport_outvq = NULL;
1084 	port->vtcport_id = -1;
1085 	mtx_destroy(&port->vtcport_mtx);
1086 	free(port, M_DEVBUF);
1087 }
1088 
1089 static int
1090 vtcon_port_init_vqs(struct vtcon_port *port)
1091 {
1092 	struct vtcon_softc_port *scport;
1093 	int error;
1094 
1095 	scport = port->vtcport_scport;
1096 
1097 	port->vtcport_invq = scport->vcsp_invq;
1098 	port->vtcport_outvq = scport->vcsp_outvq;
1099 
1100 	/*
1101 	 * Free any data left over from when this virtqueue was in use by a
1102 	 * prior port. We have not yet notified the host that the port is
1103 	 * ready, so assume nothing in the virtqueue can be for us.
1104 	 */
1105 	vtcon_port_drain(port);
1106 
1107 	KASSERT(virtqueue_empty(port->vtcport_invq),
1108 	    ("%s: in virtqueue is not empty", __func__));
1109 	KASSERT(virtqueue_empty(port->vtcport_outvq),
1110 	    ("%s: out virtqueue is not empty", __func__));
1111 
1112 	error = vtcon_port_populate(port);
1113 	if (error)
1114 		return (error);
1115 
1116 	return (0);
1117 }
1118 
1119 static int
1120 vtcon_port_create(struct vtcon_softc *sc, int id)
1121 {
1122 	device_t dev;
1123 	struct vtcon_softc_port *scport;
1124 	struct vtcon_port *port;
1125 	int error;
1126 
1127 	dev = sc->vtcon_dev;
1128 	scport = &sc->vtcon_ports[id];
1129 
1130 	VTCON_ASSERT_VALID_PORTID(sc, id);
1131 	MPASS(scport->vcsp_port == NULL);
1132 
1133 	port = malloc(sizeof(struct vtcon_port), M_DEVBUF, M_NOWAIT | M_ZERO);
1134 	if (port == NULL)
1135 		return (ENOMEM);
1136 
1137 	port->vtcport_sc = sc;
1138 	port->vtcport_scport = scport;
1139 	port->vtcport_id = id;
1140 	mtx_init(&port->vtcport_mtx, "vtcpmtx", NULL, MTX_DEF);
1141 	port->vtcport_tty = tty_alloc_mutex(&vtcon_tty_class, port,
1142 	    &port->vtcport_mtx);
1143 
1144 	error = vtcon_port_init_vqs(port);
1145 	if (error) {
1146 		VTCON_PORT_LOCK(port);
1147 		vtcon_port_teardown(port);
1148 		return (error);
1149 	}
1150 
1151 	VTCON_LOCK(sc);
1152 	VTCON_PORT_LOCK(port);
1153 	scport->vcsp_port = port;
1154 	vtcon_port_enable_intr(port);
1155 	vtcon_port_submit_event(port, VIRTIO_CONSOLE_PORT_READY, 1);
1156 	VTCON_PORT_UNLOCK(port);
1157 	VTCON_UNLOCK(sc);
1158 
1159 	tty_makedev(port->vtcport_tty, NULL, "%s%r.%r", VTCON_TTY_PREFIX,
1160 	    device_get_unit(dev), id);
1161 
1162 	return (0);
1163 }
1164 
1165 static void
1166 vtcon_port_dev_alias(struct vtcon_port *port, const char *name, size_t len)
1167 {
1168 	struct vtcon_softc *sc;
1169 	struct cdev *pdev;
1170 	struct tty *tp;
1171 	int i, error;
1172 
1173 	sc = port->vtcport_sc;
1174 	tp = port->vtcport_tty;
1175 
1176 	if (port->vtcport_flags & VTCON_PORT_FLAG_ALIAS)
1177 		return;
1178 
1179 	/* Port name is UTF-8, but we can only handle ASCII. */
1180 	for (i = 0; i < len; i++) {
1181 		if (!isascii(name[i]))
1182 			return;
1183 	}
1184 
1185 	/*
1186 	 * Port name may not conform to the devfs requirements so we cannot use
1187 	 * tty_makealias() because the MAKEDEV_CHECKNAME flag must be specified.
1188 	 */
1189 	error = make_dev_alias_p(MAKEDEV_NOWAIT | MAKEDEV_CHECKNAME, &pdev,
1190 	    tp->t_dev, "%s/%*s", VTCON_TTY_ALIAS_PREFIX, (int)len, name);
1191 	if (error) {
1192 		device_printf(sc->vtcon_dev,
1193 		    "%s: cannot make dev alias (%s/%*s) error %d\n", __func__,
1194 		    VTCON_TTY_ALIAS_PREFIX, (int)len, name, error);
1195 	} else
1196 		port->vtcport_flags |= VTCON_PORT_FLAG_ALIAS;
1197 }
1198 
1199 static void
1200 vtcon_port_drain_bufs(struct virtqueue *vq)
1201 {
1202 	void *buf;
1203 	int last;
1204 
1205 	last = 0;
1206 
1207 	while ((buf = virtqueue_drain(vq, &last)) != NULL)
1208 		free(buf, M_DEVBUF);
1209 }
1210 
1211 static void
1212 vtcon_port_drain(struct vtcon_port *port)
1213 {
1214 
1215 	vtcon_port_drain_bufs(port->vtcport_invq);
1216 }
1217 
1218 static void
1219 vtcon_port_teardown(struct vtcon_port *port)
1220 {
1221 	struct tty *tp;
1222 
1223 	tp = port->vtcport_tty;
1224 
1225 	port->vtcport_flags |= VTCON_PORT_FLAG_GONE;
1226 
1227 	if (tp != NULL) {
1228 		atomic_add_int(&vtcon_pending_free, 1);
1229 		tty_rel_gone(tp);
1230 	} else
1231 		vtcon_port_destroy(port);
1232 }
1233 
1234 static void
1235 vtcon_port_change_size(struct vtcon_port *port, uint16_t cols, uint16_t rows)
1236 {
1237 	struct tty *tp;
1238 	struct winsize sz;
1239 
1240 	tp = port->vtcport_tty;
1241 
1242 	if (tp == NULL)
1243 		return;
1244 
1245 	bzero(&sz, sizeof(struct winsize));
1246 	sz.ws_col = cols;
1247 	sz.ws_row = rows;
1248 
1249 	tty_set_winsize(tp, &sz);
1250 }
1251 
1252 static void
1253 vtcon_port_update_console_size(struct vtcon_softc *sc)
1254 {
1255 	struct vtcon_port *port;
1256 	struct vtcon_softc_port *scport;
1257 	uint16_t cols, rows;
1258 
1259 	vtcon_get_console_size(sc, &cols, &rows);
1260 
1261 	/*
1262 	 * For now, assume the first (only) port is the console. Note
1263 	 * QEMU does not implement this feature yet.
1264 	 */
1265 	scport = &sc->vtcon_ports[0];
1266 
1267 	VTCON_LOCK(sc);
1268 	port = scport->vcsp_port;
1269 
1270 	if (port != NULL) {
1271 		VTCON_PORT_LOCK(port);
1272 		VTCON_UNLOCK(sc);
1273 		vtcon_port_change_size(port, cols, rows);
1274 		VTCON_PORT_UNLOCK(port);
1275 	} else
1276 		VTCON_UNLOCK(sc);
1277 }
1278 
1279 static void
1280 vtcon_port_enable_intr(struct vtcon_port *port)
1281 {
1282 
1283 	/*
1284 	 * NOTE: The out virtqueue is always polled, so its interrupt
1285 	 * kept disabled.
1286 	 */
1287 	virtqueue_enable_intr(port->vtcport_invq);
1288 }
1289 
1290 static void
1291 vtcon_port_disable_intr(struct vtcon_port *port)
1292 {
1293 
1294 	if (port->vtcport_invq != NULL)
1295 		virtqueue_disable_intr(port->vtcport_invq);
1296 	if (port->vtcport_outvq != NULL)
1297 		virtqueue_disable_intr(port->vtcport_outvq);
1298 }
1299 
1300 static void
1301 vtcon_port_in(struct vtcon_port *port)
1302 {
1303 	struct virtqueue *vq;
1304 	struct tty *tp;
1305 	char *buf;
1306 	uint32_t len;
1307 	int i, deq;
1308 
1309 	tp = port->vtcport_tty;
1310 	vq = port->vtcport_invq;
1311 
1312 again:
1313 	deq = 0;
1314 
1315 	while ((buf = virtqueue_dequeue(vq, &len)) != NULL) {
1316 		for (i = 0; i < len; i++) {
1317 #if defined(KDB)
1318 			if (port->vtcport_flags & VTCON_PORT_FLAG_CONSOLE)
1319 				kdb_alt_break(buf[i],
1320 				    &port->vtcport_alt_break_state);
1321 #endif
1322 			ttydisc_rint(tp, buf[i], 0);
1323 		}
1324 		vtcon_port_requeue_buf(port, buf);
1325 		deq++;
1326 	}
1327 	ttydisc_rint_done(tp);
1328 
1329 	if (deq > 0)
1330 		virtqueue_notify(vq);
1331 
1332 	if (virtqueue_enable_intr(vq) != 0)
1333 		goto again;
1334 }
1335 
1336 static void
1337 vtcon_port_intr(void *scportx)
1338 {
1339 	struct vtcon_softc_port *scport;
1340 	struct vtcon_softc *sc;
1341 	struct vtcon_port *port;
1342 
1343 	scport = scportx;
1344 	sc = scport->vcsp_sc;
1345 
1346 	VTCON_LOCK(sc);
1347 	port = scport->vcsp_port;
1348 	if (port == NULL) {
1349 		VTCON_UNLOCK(sc);
1350 		return;
1351 	}
1352 	VTCON_PORT_LOCK(port);
1353 	VTCON_UNLOCK(sc);
1354 	if ((port->vtcport_flags & VTCON_PORT_FLAG_GONE) == 0)
1355 		vtcon_port_in(port);
1356 	VTCON_PORT_UNLOCK(port);
1357 }
1358 
1359 static void
1360 vtcon_port_out(struct vtcon_port *port, void *buf, int bufsize)
1361 {
1362 	struct sglist_seg segs[2];
1363 	struct sglist sg;
1364 	struct virtqueue *vq;
1365 	int error;
1366 
1367 	vq = port->vtcport_outvq;
1368 	KASSERT(virtqueue_empty(vq),
1369 	    ("%s: port %p out virtqueue not empty", __func__, port));
1370 
1371 	sglist_init(&sg, 2, segs);
1372 	error = sglist_append(&sg, buf, bufsize);
1373 	KASSERT(error == 0, ("%s: error %d adding buffer to sglist",
1374 	    __func__, error));
1375 
1376 	error = virtqueue_enqueue(vq, buf, &sg, sg.sg_nseg, 0);
1377 	if (error == 0) {
1378 		virtqueue_notify(vq);
1379 		virtqueue_poll(vq, NULL);
1380 	}
1381 }
1382 
1383 static void
1384 vtcon_port_submit_event(struct vtcon_port *port, uint16_t event,
1385     uint16_t value)
1386 {
1387 	struct vtcon_softc *sc;
1388 
1389 	sc = port->vtcport_sc;
1390 
1391 	vtcon_ctrl_send_control(sc, port->vtcport_id, event, value);
1392 }
1393 
1394 static int
1395 vtcon_tty_open(struct tty *tp)
1396 {
1397 	struct vtcon_port *port;
1398 
1399 	port = tty_softc(tp);
1400 
1401 	if (port->vtcport_flags & VTCON_PORT_FLAG_GONE)
1402 		return (ENXIO);
1403 
1404 	vtcon_port_submit_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
1405 
1406 	return (0);
1407 }
1408 
1409 static void
1410 vtcon_tty_close(struct tty *tp)
1411 {
1412 	struct vtcon_port *port;
1413 
1414 	port = tty_softc(tp);
1415 
1416 	if (port->vtcport_flags & VTCON_PORT_FLAG_GONE)
1417 		return;
1418 
1419 	vtcon_port_submit_event(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
1420 }
1421 
1422 static void
1423 vtcon_tty_outwakeup(struct tty *tp)
1424 {
1425 	struct vtcon_port *port;
1426 	char buf[VTCON_BULK_BUFSZ];
1427 	int len;
1428 
1429 	port = tty_softc(tp);
1430 
1431 	if (port->vtcport_flags & VTCON_PORT_FLAG_GONE)
1432 		return;
1433 
1434 	while ((len = ttydisc_getc(tp, buf, sizeof(buf))) != 0)
1435 		vtcon_port_out(port, buf, len);
1436 }
1437 
1438 static void
1439 vtcon_tty_free(void *xport)
1440 {
1441 	struct vtcon_port *port;
1442 
1443 	port = xport;
1444 
1445 	vtcon_port_destroy(port);
1446 	atomic_subtract_int(&vtcon_pending_free, 1);
1447 }
1448 
1449 static void
1450 vtcon_get_console_size(struct vtcon_softc *sc, uint16_t *cols, uint16_t *rows)
1451 {
1452 	struct virtio_console_config concfg;
1453 
1454 	KASSERT(sc->vtcon_flags & VTCON_FLAG_SIZE,
1455 	    ("%s: size feature not negotiated", __func__));
1456 
1457 	vtcon_read_config(sc, &concfg);
1458 
1459 	*cols = concfg.cols;
1460 	*rows = concfg.rows;
1461 }
1462 
1463 static void
1464 vtcon_enable_interrupts(struct vtcon_softc *sc)
1465 {
1466 	struct vtcon_softc_port *scport;
1467 	struct vtcon_port *port;
1468 	int i;
1469 
1470 	VTCON_LOCK(sc);
1471 
1472 	if (sc->vtcon_flags & VTCON_FLAG_MULTIPORT)
1473 		virtqueue_enable_intr(sc->vtcon_ctrl_rxvq);
1474 
1475 	for (i = 0; i < sc->vtcon_max_ports; i++) {
1476 		scport = &sc->vtcon_ports[i];
1477 
1478 		port = scport->vcsp_port;
1479 		if (port == NULL)
1480 			continue;
1481 
1482 		VTCON_PORT_LOCK(port);
1483 		vtcon_port_enable_intr(port);
1484 		VTCON_PORT_UNLOCK(port);
1485 	}
1486 
1487 	VTCON_UNLOCK(sc);
1488 }
1489 
1490 static void
1491 vtcon_disable_interrupts(struct vtcon_softc *sc)
1492 {
1493 	struct vtcon_softc_port *scport;
1494 	struct vtcon_port *port;
1495 	int i;
1496 
1497 	VTCON_LOCK_ASSERT(sc);
1498 
1499 	if (sc->vtcon_flags & VTCON_FLAG_MULTIPORT)
1500 		virtqueue_disable_intr(sc->vtcon_ctrl_rxvq);
1501 
1502 	for (i = 0; i < sc->vtcon_max_ports; i++) {
1503 		scport = &sc->vtcon_ports[i];
1504 
1505 		port = scport->vcsp_port;
1506 		if (port == NULL)
1507 			continue;
1508 
1509 		VTCON_PORT_LOCK(port);
1510 		vtcon_port_disable_intr(port);
1511 		VTCON_PORT_UNLOCK(port);
1512 	}
1513 }
1514