xref: /freebsd/sys/dev/virtio/console/virtio_console.c (revision 5c050bc4fc3c9da0614704dda8d51001c7a8b8e6)
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 
150 	{ 0, NULL }
151 };
152 
153 static int	 vtcon_modevent(module_t, int, void *);
154 static void	 vtcon_drain_all(void);
155 
156 static int	 vtcon_probe(device_t);
157 static int	 vtcon_attach(device_t);
158 static int	 vtcon_detach(device_t);
159 static int	 vtcon_config_change(device_t);
160 
161 static void	 vtcon_setup_features(struct vtcon_softc *);
162 static void	 vtcon_negotiate_features(struct vtcon_softc *);
163 static int	 vtcon_alloc_scports(struct vtcon_softc *);
164 static int	 vtcon_alloc_virtqueues(struct vtcon_softc *);
165 static void	 vtcon_read_config(struct vtcon_softc *,
166 		     struct virtio_console_config *);
167 
168 static void	 vtcon_determine_max_ports(struct vtcon_softc *,
169 		     struct virtio_console_config *);
170 static void	 vtcon_destroy_ports(struct vtcon_softc *);
171 static void	 vtcon_stop(struct vtcon_softc *);
172 
173 static int	 vtcon_ctrl_event_enqueue(struct vtcon_softc *,
174 		     struct virtio_console_control *);
175 static int	 vtcon_ctrl_event_create(struct vtcon_softc *);
176 static void	 vtcon_ctrl_event_requeue(struct vtcon_softc *,
177 		     struct virtio_console_control *);
178 static int	 vtcon_ctrl_event_populate(struct vtcon_softc *);
179 static void	 vtcon_ctrl_event_drain(struct vtcon_softc *);
180 static int	 vtcon_ctrl_init(struct vtcon_softc *);
181 static void	 vtcon_ctrl_deinit(struct vtcon_softc *);
182 static void	 vtcon_ctrl_port_add_event(struct vtcon_softc *, int);
183 static void	 vtcon_ctrl_port_remove_event(struct vtcon_softc *, int);
184 static void	 vtcon_ctrl_port_console_event(struct vtcon_softc *, int);
185 static void	 vtcon_ctrl_port_open_event(struct vtcon_softc *, int);
186 static void	 vtcon_ctrl_port_name_event(struct vtcon_softc *, int,
187 		     const char *, size_t);
188 static void	 vtcon_ctrl_process_event(struct vtcon_softc *,
189 		     struct virtio_console_control *, void *, size_t);
190 static void	 vtcon_ctrl_task_cb(void *, int);
191 static void	 vtcon_ctrl_event_intr(void *);
192 static void	 vtcon_ctrl_poll(struct vtcon_softc *,
193 		     struct virtio_console_control *control);
194 static void	 vtcon_ctrl_send_control(struct vtcon_softc *, uint32_t,
195 		     uint16_t, uint16_t);
196 
197 static int	 vtcon_port_enqueue_buf(struct vtcon_port *, void *, size_t);
198 static int	 vtcon_port_create_buf(struct vtcon_port *);
199 static void	 vtcon_port_requeue_buf(struct vtcon_port *, void *);
200 static int	 vtcon_port_populate(struct vtcon_port *);
201 static void	 vtcon_port_destroy(struct vtcon_port *);
202 static int	 vtcon_port_create(struct vtcon_softc *, int);
203 static void	 vtcon_port_dev_alias(struct vtcon_port *, const char *,
204 		     size_t);
205 static void	 vtcon_port_drain_bufs(struct virtqueue *);
206 static void	 vtcon_port_drain(struct vtcon_port *);
207 static void	 vtcon_port_teardown(struct vtcon_port *);
208 static void	 vtcon_port_change_size(struct vtcon_port *, uint16_t,
209 		     uint16_t);
210 static void	 vtcon_port_update_console_size(struct vtcon_softc *);
211 static void	 vtcon_port_enable_intr(struct vtcon_port *);
212 static void	 vtcon_port_disable_intr(struct vtcon_port *);
213 static void	 vtcon_port_in(struct vtcon_port *);
214 static void	 vtcon_port_intr(void *);
215 static void	 vtcon_port_out(struct vtcon_port *, void *, int);
216 static void	 vtcon_port_submit_event(struct vtcon_port *, uint16_t,
217 		     uint16_t);
218 
219 static int	 vtcon_tty_open(struct tty *);
220 static void	 vtcon_tty_close(struct tty *);
221 static void	 vtcon_tty_outwakeup(struct tty *);
222 static void	 vtcon_tty_free(void *);
223 
224 static void	 vtcon_get_console_size(struct vtcon_softc *, uint16_t *,
225 		     uint16_t *);
226 
227 static void	 vtcon_enable_interrupts(struct vtcon_softc *);
228 static void	 vtcon_disable_interrupts(struct vtcon_softc *);
229 
230 static int	 vtcon_pending_free;
231 
232 static struct ttydevsw vtcon_tty_class = {
233 	.tsw_flags	= 0,
234 	.tsw_open	= vtcon_tty_open,
235 	.tsw_close	= vtcon_tty_close,
236 	.tsw_outwakeup	= vtcon_tty_outwakeup,
237 	.tsw_free	= vtcon_tty_free,
238 };
239 
240 static device_method_t vtcon_methods[] = {
241 	/* Device methods. */
242 	DEVMETHOD(device_probe,		vtcon_probe),
243 	DEVMETHOD(device_attach,	vtcon_attach),
244 	DEVMETHOD(device_detach,	vtcon_detach),
245 
246 	/* VirtIO methods. */
247 	DEVMETHOD(virtio_config_change,	vtcon_config_change),
248 
249 	DEVMETHOD_END
250 };
251 
252 static driver_t vtcon_driver = {
253 	"vtcon",
254 	vtcon_methods,
255 	sizeof(struct vtcon_softc)
256 };
257 static devclass_t vtcon_devclass;
258 
259 DRIVER_MODULE(virtio_console, virtio_pci, vtcon_driver, vtcon_devclass,
260     vtcon_modevent, 0);
261 MODULE_VERSION(virtio_console, 1);
262 MODULE_DEPEND(virtio_console, virtio, 1, 1, 1);
263 
264 static int
265 vtcon_modevent(module_t mod, int type, void *unused)
266 {
267 	int error;
268 
269 	switch (type) {
270 	case MOD_LOAD:
271 		error = 0;
272 		break;
273 	case MOD_QUIESCE:
274 		error = 0;
275 		break;
276 	case MOD_UNLOAD:
277 		vtcon_drain_all();
278 		error = 0;
279 		break;
280 	case MOD_SHUTDOWN:
281 		error = 0;
282 		break;
283 	default:
284 		error = EOPNOTSUPP;
285 		break;
286 	}
287 
288 	return (error);
289 }
290 
291 static void
292 vtcon_drain_all(void)
293 {
294 	int first;
295 
296 	for (first = 1; vtcon_pending_free != 0; first = 0) {
297 		if (first != 0) {
298 			printf("virtio_console: Waiting for all detached TTY "
299 			    "devices to have open fds closed.\n");
300 		}
301 		pause("vtcondra", hz);
302 	}
303 }
304 
305 static int
306 vtcon_probe(device_t dev)
307 {
308 
309 	if (virtio_get_device_type(dev) != VIRTIO_ID_CONSOLE)
310 		return (ENXIO);
311 
312 	device_set_desc(dev, "VirtIO Console Adapter");
313 
314 	return (BUS_PROBE_DEFAULT);
315 }
316 
317 static int
318 vtcon_attach(device_t dev)
319 {
320 	struct vtcon_softc *sc;
321 	struct virtio_console_config concfg;
322 	int error;
323 
324 	sc = device_get_softc(dev);
325 	sc->vtcon_dev = dev;
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 	virtio_set_feature_desc(dev, vtcon_feature_desc);
331 	vtcon_setup_features(sc);
332 
333 	vtcon_read_config(sc, &concfg);
334 	vtcon_determine_max_ports(sc, &concfg);
335 
336 	error = vtcon_alloc_scports(sc);
337 	if (error) {
338 		device_printf(dev, "cannot allocate softc port structures\n");
339 		goto fail;
340 	}
341 
342 	error = vtcon_alloc_virtqueues(sc);
343 	if (error) {
344 		device_printf(dev, "cannot allocate virtqueues\n");
345 		goto fail;
346 	}
347 
348 	if (sc->vtcon_flags & VTCON_FLAG_MULTIPORT) {
349 		TASK_INIT(&sc->vtcon_ctrl_task, 0, vtcon_ctrl_task_cb, sc);
350 		error = vtcon_ctrl_init(sc);
351 		if (error)
352 			goto fail;
353 	} else {
354 		error = vtcon_port_create(sc, 0);
355 		if (error)
356 			goto fail;
357 		if (sc->vtcon_flags & VTCON_FLAG_SIZE)
358 			vtcon_port_update_console_size(sc);
359 	}
360 
361 	error = virtio_setup_intr(dev, INTR_TYPE_TTY);
362 	if (error) {
363 		device_printf(dev, "cannot setup virtqueue interrupts\n");
364 		goto fail;
365 	}
366 
367 	vtcon_enable_interrupts(sc);
368 
369 	vtcon_ctrl_send_control(sc, VIRTIO_CONSOLE_BAD_ID,
370 	    VIRTIO_CONSOLE_DEVICE_READY, 1);
371 
372 fail:
373 	if (error)
374 		vtcon_detach(dev);
375 
376 	return (error);
377 }
378 
379 static int
380 vtcon_detach(device_t dev)
381 {
382 	struct vtcon_softc *sc;
383 
384 	sc = device_get_softc(dev);
385 
386 	VTCON_LOCK(sc);
387 	sc->vtcon_flags |= VTCON_FLAG_DETACHED;
388 	if (device_is_attached(dev))
389 		vtcon_stop(sc);
390 	VTCON_UNLOCK(sc);
391 
392 	if (sc->vtcon_flags & VTCON_FLAG_MULTIPORT) {
393 		taskqueue_drain(taskqueue_thread, &sc->vtcon_ctrl_task);
394 		vtcon_ctrl_deinit(sc);
395 	}
396 
397 	vtcon_destroy_ports(sc);
398 	mtx_destroy(&sc->vtcon_mtx);
399 	mtx_destroy(&sc->vtcon_ctrl_tx_mtx);
400 
401 	return (0);
402 }
403 
404 static int
405 vtcon_config_change(device_t dev)
406 {
407 	struct vtcon_softc *sc;
408 
409 	sc = device_get_softc(dev);
410 
411 	/*
412 	 * When the multiport feature is negotiated, all configuration
413 	 * changes are done through control virtqueue events.
414 	 */
415 	if ((sc->vtcon_flags & VTCON_FLAG_MULTIPORT) == 0) {
416 		if (sc->vtcon_flags & VTCON_FLAG_SIZE)
417 			vtcon_port_update_console_size(sc);
418 	}
419 
420 	return (0);
421 }
422 
423 static void
424 vtcon_negotiate_features(struct vtcon_softc *sc)
425 {
426 	device_t dev;
427 	uint64_t features;
428 
429 	dev = sc->vtcon_dev;
430 	features = VTCON_FEATURES;
431 
432 	sc->vtcon_features = virtio_negotiate_features(dev, features);
433 }
434 
435 static void
436 vtcon_setup_features(struct vtcon_softc *sc)
437 {
438 	device_t dev;
439 
440 	dev = sc->vtcon_dev;
441 
442 	vtcon_negotiate_features(sc);
443 
444 	if (virtio_with_feature(dev, VIRTIO_CONSOLE_F_SIZE))
445 		sc->vtcon_flags |= VTCON_FLAG_SIZE;
446 	if (virtio_with_feature(dev, VIRTIO_CONSOLE_F_MULTIPORT))
447 		sc->vtcon_flags |= VTCON_FLAG_MULTIPORT;
448 }
449 
450 #define VTCON_GET_CONFIG(_dev, _feature, _field, _cfg)			\
451 	if (virtio_with_feature(_dev, _feature)) {			\
452 		virtio_read_device_config(_dev,				\
453 		    offsetof(struct virtio_console_config, _field),	\
454 		    &(_cfg)->_field, sizeof((_cfg)->_field));		\
455 	}
456 
457 static void
458 vtcon_read_config(struct vtcon_softc *sc, struct virtio_console_config *concfg)
459 {
460 	device_t dev;
461 
462 	dev = sc->vtcon_dev;
463 
464 	bzero(concfg, sizeof(struct virtio_console_config));
465 
466 	VTCON_GET_CONFIG(dev, VIRTIO_CONSOLE_F_SIZE, cols, concfg);
467 	VTCON_GET_CONFIG(dev, VIRTIO_CONSOLE_F_SIZE, rows, concfg);
468 	VTCON_GET_CONFIG(dev, VIRTIO_CONSOLE_F_MULTIPORT, max_nr_ports, concfg);
469 }
470 
471 #undef VTCON_GET_CONFIG
472 
473 static int
474 vtcon_alloc_scports(struct vtcon_softc *sc)
475 {
476 	struct vtcon_softc_port *scport;
477 	u_int max, i;
478 
479 	max = sc->vtcon_max_ports;
480 
481 	sc->vtcon_ports = mallocarray(max, sizeof(struct vtcon_softc_port),
482 	    M_DEVBUF, M_NOWAIT | M_ZERO);
483 	if (sc->vtcon_ports == NULL)
484 		return (ENOMEM);
485 
486 	for (i = 0; i < max; i++) {
487 		scport = &sc->vtcon_ports[i];
488 		scport->vcsp_sc = sc;
489 	}
490 
491 	return (0);
492 }
493 
494 static int
495 vtcon_alloc_virtqueues(struct vtcon_softc *sc)
496 {
497 	device_t dev;
498 	struct vq_alloc_info *info;
499 	struct vtcon_softc_port *scport;
500 	u_int i, idx, portidx, nvqs;
501 	int error;
502 
503 	dev = sc->vtcon_dev;
504 
505 	nvqs = sc->vtcon_max_ports * 2;
506 	if (sc->vtcon_flags & VTCON_FLAG_MULTIPORT)
507 		nvqs += 2;
508 
509 	info = mallocarray(nvqs, sizeof(struct vq_alloc_info), M_TEMP,
510 	    M_NOWAIT);
511 	if (info == NULL)
512 		return (ENOMEM);
513 
514 	for (i = 0, idx = 0, portidx = 0; i < nvqs / 2; i++, idx += 2) {
515 
516 		if (i == 1) {
517 			/* The control virtqueues are after the first port. */
518 			VQ_ALLOC_INFO_INIT(&info[idx], 0,
519 			    vtcon_ctrl_event_intr, sc, &sc->vtcon_ctrl_rxvq,
520 			    "%s-control rx", device_get_nameunit(dev));
521 			VQ_ALLOC_INFO_INIT(&info[idx+1], 0,
522 			    NULL, sc, &sc->vtcon_ctrl_txvq,
523 			    "%s-control tx", device_get_nameunit(dev));
524 			continue;
525 		}
526 
527 		scport = &sc->vtcon_ports[portidx];
528 
529 		VQ_ALLOC_INFO_INIT(&info[idx], 0, vtcon_port_intr,
530 		    scport, &scport->vcsp_invq, "%s-port%d in",
531 		    device_get_nameunit(dev), i);
532 		VQ_ALLOC_INFO_INIT(&info[idx+1], 0, NULL,
533 		    NULL, &scport->vcsp_outvq, "%s-port%d out",
534 		    device_get_nameunit(dev), i);
535 
536 		portidx++;
537 	}
538 
539 	error = virtio_alloc_virtqueues(dev, 0, nvqs, info);
540 	free(info, M_TEMP);
541 
542 	return (error);
543 }
544 
545 static void
546 vtcon_determine_max_ports(struct vtcon_softc *sc,
547     struct virtio_console_config *concfg)
548 {
549 
550 	if (sc->vtcon_flags & VTCON_FLAG_MULTIPORT) {
551 		sc->vtcon_max_ports =
552 		    min(concfg->max_nr_ports, VTCON_MAX_PORTS);
553 		if (sc->vtcon_max_ports == 0)
554 			sc->vtcon_max_ports = 1;
555 	} else
556 		sc->vtcon_max_ports = 1;
557 }
558 
559 static void
560 vtcon_destroy_ports(struct vtcon_softc *sc)
561 {
562 	struct vtcon_softc_port *scport;
563 	struct vtcon_port *port;
564 	struct virtqueue *vq;
565 	int i;
566 
567 	if (sc->vtcon_ports == NULL)
568 		return;
569 
570 	VTCON_LOCK(sc);
571 	for (i = 0; i < sc->vtcon_max_ports; i++) {
572 		scport = &sc->vtcon_ports[i];
573 
574 		port = scport->vcsp_port;
575 		if (port != NULL) {
576 			scport->vcsp_port = NULL;
577 			VTCON_PORT_LOCK(port);
578 			VTCON_UNLOCK(sc);
579 			vtcon_port_teardown(port);
580 			VTCON_LOCK(sc);
581 		}
582 
583 		vq = scport->vcsp_invq;
584 		if (vq != NULL)
585 			vtcon_port_drain_bufs(vq);
586 	}
587 	VTCON_UNLOCK(sc);
588 
589 	free(sc->vtcon_ports, M_DEVBUF);
590 	sc->vtcon_ports = NULL;
591 }
592 
593 static void
594 vtcon_stop(struct vtcon_softc *sc)
595 {
596 
597 	vtcon_disable_interrupts(sc);
598 	virtio_stop(sc->vtcon_dev);
599 }
600 
601 static int
602 vtcon_ctrl_event_enqueue(struct vtcon_softc *sc,
603     struct virtio_console_control *control)
604 {
605 	struct sglist_seg segs[2];
606 	struct sglist sg;
607 	struct virtqueue *vq;
608 	int error;
609 
610 	vq = sc->vtcon_ctrl_rxvq;
611 
612 	sglist_init(&sg, 2, segs);
613 	error = sglist_append(&sg, control, VTCON_CTRL_BUFSZ);
614 	KASSERT(error == 0, ("%s: error %d adding control to sglist",
615 	    __func__, error));
616 
617 	return (virtqueue_enqueue(vq, control, &sg, 0, sg.sg_nseg));
618 }
619 
620 static int
621 vtcon_ctrl_event_create(struct vtcon_softc *sc)
622 {
623 	struct virtio_console_control *control;
624 	int error;
625 
626 	control = malloc(VTCON_CTRL_BUFSZ, M_DEVBUF, M_ZERO | M_NOWAIT);
627 	if (control == NULL)
628 		return (ENOMEM);
629 
630 	error = vtcon_ctrl_event_enqueue(sc, control);
631 	if (error)
632 		free(control, M_DEVBUF);
633 
634 	return (error);
635 }
636 
637 static void
638 vtcon_ctrl_event_requeue(struct vtcon_softc *sc,
639     struct virtio_console_control *control)
640 {
641 	int error;
642 
643 	bzero(control, VTCON_CTRL_BUFSZ);
644 
645 	error = vtcon_ctrl_event_enqueue(sc, control);
646 	KASSERT(error == 0,
647 	    ("%s: cannot requeue control buffer %d", __func__, error));
648 }
649 
650 static int
651 vtcon_ctrl_event_populate(struct vtcon_softc *sc)
652 {
653 	struct virtqueue *vq;
654 	int nbufs, error;
655 
656 	vq = sc->vtcon_ctrl_rxvq;
657 	error = ENOSPC;
658 
659 	for (nbufs = 0; !virtqueue_full(vq); nbufs++) {
660 		error = vtcon_ctrl_event_create(sc);
661 		if (error)
662 			break;
663 	}
664 
665 	if (nbufs > 0) {
666 		virtqueue_notify(vq);
667 		error = 0;
668 	}
669 
670 	return (error);
671 }
672 
673 static void
674 vtcon_ctrl_event_drain(struct vtcon_softc *sc)
675 {
676 	struct virtio_console_control *control;
677 	struct virtqueue *vq;
678 	int last;
679 
680 	vq = sc->vtcon_ctrl_rxvq;
681 	last = 0;
682 
683 	if (vq == NULL)
684 		return;
685 
686 	VTCON_LOCK(sc);
687 	while ((control = virtqueue_drain(vq, &last)) != NULL)
688 		free(control, M_DEVBUF);
689 	VTCON_UNLOCK(sc);
690 }
691 
692 static int
693 vtcon_ctrl_init(struct vtcon_softc *sc)
694 {
695 	int error;
696 
697 	error = vtcon_ctrl_event_populate(sc);
698 
699 	return (error);
700 }
701 
702 static void
703 vtcon_ctrl_deinit(struct vtcon_softc *sc)
704 {
705 
706 	vtcon_ctrl_event_drain(sc);
707 }
708 
709 static void
710 vtcon_ctrl_port_add_event(struct vtcon_softc *sc, int id)
711 {
712 	device_t dev;
713 	int error;
714 
715 	dev = sc->vtcon_dev;
716 
717 	/* This single thread only way for ports to be created. */
718 	if (sc->vtcon_ports[id].vcsp_port != NULL) {
719 		device_printf(dev, "%s: adding port %d, but already exists\n",
720 		    __func__, id);
721 		return;
722 	}
723 
724 	error = vtcon_port_create(sc, id);
725 	if (error) {
726 		device_printf(dev, "%s: cannot create port %d: %d\n",
727 		    __func__, id, error);
728 		vtcon_ctrl_send_control(sc, id, VIRTIO_CONSOLE_PORT_READY, 0);
729 		return;
730 	}
731 }
732 
733 static void
734 vtcon_ctrl_port_remove_event(struct vtcon_softc *sc, int id)
735 {
736 	device_t dev;
737 	struct vtcon_softc_port *scport;
738 	struct vtcon_port *port;
739 
740 	dev = sc->vtcon_dev;
741 	scport = &sc->vtcon_ports[id];
742 
743 	VTCON_LOCK(sc);
744 	port = scport->vcsp_port;
745 	if (port == NULL) {
746 		VTCON_UNLOCK(sc);
747 		device_printf(dev, "%s: remove port %d, but does not exist\n",
748 		    __func__, id);
749 		return;
750 	}
751 
752 	scport->vcsp_port = NULL;
753 	VTCON_PORT_LOCK(port);
754 	VTCON_UNLOCK(sc);
755 	vtcon_port_teardown(port);
756 }
757 
758 static void
759 vtcon_ctrl_port_console_event(struct vtcon_softc *sc, int id)
760 {
761 	device_t dev;
762 	struct vtcon_softc_port *scport;
763 	struct vtcon_port *port;
764 
765 	dev = sc->vtcon_dev;
766 	scport = &sc->vtcon_ports[id];
767 
768 	VTCON_LOCK(sc);
769 	port = scport->vcsp_port;
770 	if (port == NULL) {
771 		VTCON_UNLOCK(sc);
772 		device_printf(dev, "%s: console port %d, but does not exist\n",
773 		    __func__, id);
774 		return;
775 	}
776 
777 	VTCON_PORT_LOCK(port);
778 	VTCON_UNLOCK(sc);
779 	port->vtcport_flags |= VTCON_PORT_FLAG_CONSOLE;
780 	vtcon_port_submit_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
781 	VTCON_PORT_UNLOCK(port);
782 }
783 
784 static void
785 vtcon_ctrl_port_open_event(struct vtcon_softc *sc, int id)
786 {
787 	device_t dev;
788 	struct vtcon_softc_port *scport;
789 	struct vtcon_port *port;
790 
791 	dev = sc->vtcon_dev;
792 	scport = &sc->vtcon_ports[id];
793 
794 	VTCON_LOCK(sc);
795 	port = scport->vcsp_port;
796 	if (port == NULL) {
797 		VTCON_UNLOCK(sc);
798 		device_printf(dev, "%s: open port %d, but does not exist\n",
799 		    __func__, id);
800 		return;
801 	}
802 
803 	VTCON_PORT_LOCK(port);
804 	VTCON_UNLOCK(sc);
805 	vtcon_port_enable_intr(port);
806 	VTCON_PORT_UNLOCK(port);
807 }
808 
809 static void
810 vtcon_ctrl_port_name_event(struct vtcon_softc *sc, int id, const char *name,
811     size_t len)
812 {
813 	device_t dev;
814 	struct vtcon_softc_port *scport;
815 	struct vtcon_port *port;
816 
817 	dev = sc->vtcon_dev;
818 	scport = &sc->vtcon_ports[id];
819 
820 	/*
821 	 * The VirtIO specification says the NUL terminator is not included in
822 	 * the length, but QEMU includes it. Adjust the length if needed.
823 	 */
824 	if (name == NULL || len == 0)
825 		return;
826 	if (name[len - 1] == '\0') {
827 		len--;
828 		if (len == 0)
829 			return;
830 	}
831 
832 	VTCON_LOCK(sc);
833 	port = scport->vcsp_port;
834 	if (port == NULL) {
835 		VTCON_UNLOCK(sc);
836 		device_printf(dev, "%s: name port %d, but does not exist\n",
837 		    __func__, id);
838 		return;
839 	}
840 
841 	VTCON_PORT_LOCK(port);
842 	VTCON_UNLOCK(sc);
843 	vtcon_port_dev_alias(port, name, len);
844 	VTCON_PORT_UNLOCK(port);
845 }
846 
847 static void
848 vtcon_ctrl_process_event(struct vtcon_softc *sc,
849     struct virtio_console_control *control, void *data, size_t data_len)
850 {
851 	device_t dev;
852 	int id;
853 
854 	dev = sc->vtcon_dev;
855 	id = control->id;
856 
857 	if (id < 0 || id >= sc->vtcon_max_ports) {
858 		device_printf(dev, "%s: invalid port ID %d\n", __func__, id);
859 		return;
860 	}
861 
862 	switch (control->event) {
863 	case VIRTIO_CONSOLE_PORT_ADD:
864 		vtcon_ctrl_port_add_event(sc, id);
865 		break;
866 
867 	case VIRTIO_CONSOLE_PORT_REMOVE:
868 		vtcon_ctrl_port_remove_event(sc, id);
869 		break;
870 
871 	case VIRTIO_CONSOLE_CONSOLE_PORT:
872 		vtcon_ctrl_port_console_event(sc, id);
873 		break;
874 
875 	case VIRTIO_CONSOLE_RESIZE:
876 		break;
877 
878 	case VIRTIO_CONSOLE_PORT_OPEN:
879 		vtcon_ctrl_port_open_event(sc, id);
880 		break;
881 
882 	case VIRTIO_CONSOLE_PORT_NAME:
883 		vtcon_ctrl_port_name_event(sc, id, (const char *)data, data_len);
884 		break;
885 	}
886 }
887 
888 static void
889 vtcon_ctrl_task_cb(void *xsc, int pending)
890 {
891 	struct vtcon_softc *sc;
892 	struct virtqueue *vq;
893 	struct virtio_console_control *control;
894 	void *data;
895 	size_t data_len;
896 	int detached;
897 	uint32_t len;
898 
899 	sc = xsc;
900 	vq = sc->vtcon_ctrl_rxvq;
901 
902 	VTCON_LOCK(sc);
903 
904 	while ((detached = (sc->vtcon_flags & VTCON_FLAG_DETACHED)) == 0) {
905 		control = virtqueue_dequeue(vq, &len);
906 		if (control == NULL)
907 			break;
908 
909 		if (len > sizeof(struct virtio_console_control)) {
910 			data = (void *) &control[1];
911 			data_len = len - sizeof(struct virtio_console_control);
912 		} else {
913 			data = NULL;
914 			data_len = 0;
915 		}
916 
917 		VTCON_UNLOCK(sc);
918 		vtcon_ctrl_process_event(sc, control, data, data_len);
919 		VTCON_LOCK(sc);
920 		vtcon_ctrl_event_requeue(sc, control);
921 	}
922 
923 	if (!detached) {
924 		virtqueue_notify(vq);
925 		if (virtqueue_enable_intr(vq) != 0)
926 			taskqueue_enqueue(taskqueue_thread,
927 			    &sc->vtcon_ctrl_task);
928 	}
929 
930 	VTCON_UNLOCK(sc);
931 }
932 
933 static void
934 vtcon_ctrl_event_intr(void *xsc)
935 {
936 	struct vtcon_softc *sc;
937 
938 	sc = xsc;
939 
940 	/*
941 	 * Only some events require us to potentially block, but it
942 	 * easier to just defer all event handling to the taskqueue.
943 	 */
944 	taskqueue_enqueue(taskqueue_thread, &sc->vtcon_ctrl_task);
945 }
946 
947 static void
948 vtcon_ctrl_poll(struct vtcon_softc *sc,
949     struct virtio_console_control *control)
950 {
951 	struct sglist_seg segs[2];
952 	struct sglist sg;
953 	struct virtqueue *vq;
954 	int error;
955 
956 	vq = sc->vtcon_ctrl_txvq;
957 
958 	sglist_init(&sg, 2, segs);
959 	error = sglist_append(&sg, control,
960 	    sizeof(struct virtio_console_control));
961 	KASSERT(error == 0, ("%s: error %d adding control to sglist",
962 	    __func__, error));
963 
964 	/*
965 	 * We cannot use the softc lock to serialize access to this
966 	 * virtqueue since this is called from the tty layer with the
967 	 * port lock held. Acquiring the softc would violate our lock
968 	 * ordering.
969 	 */
970 	VTCON_CTRL_TX_LOCK(sc);
971 	KASSERT(virtqueue_empty(vq),
972 	    ("%s: virtqueue is not emtpy", __func__));
973 	error = virtqueue_enqueue(vq, control, &sg, sg.sg_nseg, 0);
974 	if (error == 0) {
975 		virtqueue_notify(vq);
976 		virtqueue_poll(vq, NULL);
977 	}
978 	VTCON_CTRL_TX_UNLOCK(sc);
979 }
980 
981 static void
982 vtcon_ctrl_send_control(struct vtcon_softc *sc, uint32_t portid,
983     uint16_t event, uint16_t value)
984 {
985 	struct virtio_console_control control;
986 
987 	if ((sc->vtcon_flags & VTCON_FLAG_MULTIPORT) == 0)
988 		return;
989 
990 	control.id = portid;
991 	control.event = event;
992 	control.value = value;
993 
994 	vtcon_ctrl_poll(sc, &control);
995 }
996 
997 static int
998 vtcon_port_enqueue_buf(struct vtcon_port *port, void *buf, size_t len)
999 {
1000 	struct sglist_seg segs[2];
1001 	struct sglist sg;
1002 	struct virtqueue *vq;
1003 	int error;
1004 
1005 	vq = port->vtcport_invq;
1006 
1007 	sglist_init(&sg, 2, segs);
1008 	error = sglist_append(&sg, buf, len);
1009 	KASSERT(error == 0,
1010 	    ("%s: error %d adding buffer to sglist", __func__, error));
1011 
1012 	error = virtqueue_enqueue(vq, buf, &sg, 0, sg.sg_nseg);
1013 
1014 	return (error);
1015 }
1016 
1017 static int
1018 vtcon_port_create_buf(struct vtcon_port *port)
1019 {
1020 	void *buf;
1021 	int error;
1022 
1023 	buf = malloc(VTCON_BULK_BUFSZ, M_DEVBUF, M_ZERO | M_NOWAIT);
1024 	if (buf == NULL)
1025 		return (ENOMEM);
1026 
1027 	error = vtcon_port_enqueue_buf(port, buf, VTCON_BULK_BUFSZ);
1028 	if (error)
1029 		free(buf, M_DEVBUF);
1030 
1031 	return (error);
1032 }
1033 
1034 static void
1035 vtcon_port_requeue_buf(struct vtcon_port *port, void *buf)
1036 {
1037 	int error;
1038 
1039 	error = vtcon_port_enqueue_buf(port, buf, VTCON_BULK_BUFSZ);
1040 	KASSERT(error == 0,
1041 	    ("%s: cannot requeue input buffer %d", __func__, error));
1042 }
1043 
1044 static int
1045 vtcon_port_populate(struct vtcon_port *port)
1046 {
1047 	struct virtqueue *vq;
1048 	int nbufs, error;
1049 
1050 	vq = port->vtcport_invq;
1051 	error = ENOSPC;
1052 
1053 	for (nbufs = 0; !virtqueue_full(vq); nbufs++) {
1054 		error = vtcon_port_create_buf(port);
1055 		if (error)
1056 			break;
1057 	}
1058 
1059 	if (nbufs > 0) {
1060 		virtqueue_notify(vq);
1061 		error = 0;
1062 	}
1063 
1064 	return (error);
1065 }
1066 
1067 static void
1068 vtcon_port_destroy(struct vtcon_port *port)
1069 {
1070 
1071 	port->vtcport_sc = NULL;
1072 	port->vtcport_scport = NULL;
1073 	port->vtcport_invq = NULL;
1074 	port->vtcport_outvq = NULL;
1075 	port->vtcport_id = -1;
1076 	mtx_destroy(&port->vtcport_mtx);
1077 	free(port, M_DEVBUF);
1078 }
1079 
1080 static int
1081 vtcon_port_init_vqs(struct vtcon_port *port)
1082 {
1083 	struct vtcon_softc_port *scport;
1084 	int error;
1085 
1086 	scport = port->vtcport_scport;
1087 
1088 	port->vtcport_invq = scport->vcsp_invq;
1089 	port->vtcport_outvq = scport->vcsp_outvq;
1090 
1091 	/*
1092 	 * Free any data left over from when this virtqueue was in use by a
1093 	 * prior port. We have not yet notified the host that the port is
1094 	 * ready, so assume nothing in the virtqueue can be for us.
1095 	 */
1096 	vtcon_port_drain(port);
1097 
1098 	KASSERT(virtqueue_empty(port->vtcport_invq),
1099 	    ("%s: in virtqueue is not empty", __func__));
1100 	KASSERT(virtqueue_empty(port->vtcport_outvq),
1101 	    ("%s: out virtqueue is not empty", __func__));
1102 
1103 	error = vtcon_port_populate(port);
1104 	if (error)
1105 		return (error);
1106 
1107 	return (0);
1108 }
1109 
1110 static int
1111 vtcon_port_create(struct vtcon_softc *sc, int id)
1112 {
1113 	device_t dev;
1114 	struct vtcon_softc_port *scport;
1115 	struct vtcon_port *port;
1116 	int error;
1117 
1118 	dev = sc->vtcon_dev;
1119 	scport = &sc->vtcon_ports[id];
1120 
1121 	VTCON_ASSERT_VALID_PORTID(sc, id);
1122 	MPASS(scport->vcsp_port == NULL);
1123 
1124 	port = malloc(sizeof(struct vtcon_port), M_DEVBUF, M_NOWAIT | M_ZERO);
1125 	if (port == NULL)
1126 		return (ENOMEM);
1127 
1128 	port->vtcport_sc = sc;
1129 	port->vtcport_scport = scport;
1130 	port->vtcport_id = id;
1131 	mtx_init(&port->vtcport_mtx, "vtcpmtx", NULL, MTX_DEF);
1132 	port->vtcport_tty = tty_alloc_mutex(&vtcon_tty_class, port,
1133 	    &port->vtcport_mtx);
1134 
1135 	error = vtcon_port_init_vqs(port);
1136 	if (error) {
1137 		VTCON_PORT_LOCK(port);
1138 		vtcon_port_teardown(port);
1139 		return (error);
1140 	}
1141 
1142 	VTCON_LOCK(sc);
1143 	VTCON_PORT_LOCK(port);
1144 	scport->vcsp_port = port;
1145 	vtcon_port_enable_intr(port);
1146 	vtcon_port_submit_event(port, VIRTIO_CONSOLE_PORT_READY, 1);
1147 	VTCON_PORT_UNLOCK(port);
1148 	VTCON_UNLOCK(sc);
1149 
1150 	tty_makedev(port->vtcport_tty, NULL, "%s%r.%r", VTCON_TTY_PREFIX,
1151 	    device_get_unit(dev), id);
1152 
1153 	return (0);
1154 }
1155 
1156 static void
1157 vtcon_port_dev_alias(struct vtcon_port *port, const char *name, size_t len)
1158 {
1159 	struct vtcon_softc *sc;
1160 	struct cdev *pdev;
1161 	struct tty *tp;
1162 	int i, error;
1163 
1164 	sc = port->vtcport_sc;
1165 	tp = port->vtcport_tty;
1166 
1167 	if (port->vtcport_flags & VTCON_PORT_FLAG_ALIAS)
1168 		return;
1169 
1170 	/* Port name is UTF-8, but we can only handle ASCII. */
1171 	for (i = 0; i < len; i++) {
1172 		if (!isascii(name[i]))
1173 			return;
1174 	}
1175 
1176 	/*
1177 	 * Port name may not conform to the devfs requirements so we cannot use
1178 	 * tty_makealias() because the MAKEDEV_CHECKNAME flag must be specified.
1179 	 */
1180 	error = make_dev_alias_p(MAKEDEV_NOWAIT | MAKEDEV_CHECKNAME, &pdev,
1181 	    tp->t_dev, "%s/%*s", VTCON_TTY_ALIAS_PREFIX, (int)len, name);
1182 	if (error) {
1183 		device_printf(sc->vtcon_dev,
1184 		    "%s: cannot make dev alias (%s/%*s) error %d\n", __func__,
1185 		    VTCON_TTY_ALIAS_PREFIX, (int)len, name, error);
1186 	} else
1187 		port->vtcport_flags |= VTCON_PORT_FLAG_ALIAS;
1188 }
1189 
1190 static void
1191 vtcon_port_drain_bufs(struct virtqueue *vq)
1192 {
1193 	void *buf;
1194 	int last;
1195 
1196 	last = 0;
1197 
1198 	while ((buf = virtqueue_drain(vq, &last)) != NULL)
1199 		free(buf, M_DEVBUF);
1200 }
1201 
1202 static void
1203 vtcon_port_drain(struct vtcon_port *port)
1204 {
1205 
1206 	vtcon_port_drain_bufs(port->vtcport_invq);
1207 }
1208 
1209 static void
1210 vtcon_port_teardown(struct vtcon_port *port)
1211 {
1212 	struct tty *tp;
1213 
1214 	tp = port->vtcport_tty;
1215 
1216 	port->vtcport_flags |= VTCON_PORT_FLAG_GONE;
1217 
1218 	if (tp != NULL) {
1219 		atomic_add_int(&vtcon_pending_free, 1);
1220 		tty_rel_gone(tp);
1221 	} else
1222 		vtcon_port_destroy(port);
1223 }
1224 
1225 static void
1226 vtcon_port_change_size(struct vtcon_port *port, uint16_t cols, uint16_t rows)
1227 {
1228 	struct tty *tp;
1229 	struct winsize sz;
1230 
1231 	tp = port->vtcport_tty;
1232 
1233 	if (tp == NULL)
1234 		return;
1235 
1236 	bzero(&sz, sizeof(struct winsize));
1237 	sz.ws_col = cols;
1238 	sz.ws_row = rows;
1239 
1240 	tty_set_winsize(tp, &sz);
1241 }
1242 
1243 static void
1244 vtcon_port_update_console_size(struct vtcon_softc *sc)
1245 {
1246 	struct vtcon_port *port;
1247 	struct vtcon_softc_port *scport;
1248 	uint16_t cols, rows;
1249 
1250 	vtcon_get_console_size(sc, &cols, &rows);
1251 
1252 	/*
1253 	 * For now, assume the first (only) port is the console. Note
1254 	 * QEMU does not implement this feature yet.
1255 	 */
1256 	scport = &sc->vtcon_ports[0];
1257 
1258 	VTCON_LOCK(sc);
1259 	port = scport->vcsp_port;
1260 
1261 	if (port != NULL) {
1262 		VTCON_PORT_LOCK(port);
1263 		VTCON_UNLOCK(sc);
1264 		vtcon_port_change_size(port, cols, rows);
1265 		VTCON_PORT_UNLOCK(port);
1266 	} else
1267 		VTCON_UNLOCK(sc);
1268 }
1269 
1270 static void
1271 vtcon_port_enable_intr(struct vtcon_port *port)
1272 {
1273 
1274 	/*
1275 	 * NOTE: The out virtqueue is always polled, so its interrupt
1276 	 * kept disabled.
1277 	 */
1278 	virtqueue_enable_intr(port->vtcport_invq);
1279 }
1280 
1281 static void
1282 vtcon_port_disable_intr(struct vtcon_port *port)
1283 {
1284 
1285 	if (port->vtcport_invq != NULL)
1286 		virtqueue_disable_intr(port->vtcport_invq);
1287 	if (port->vtcport_outvq != NULL)
1288 		virtqueue_disable_intr(port->vtcport_outvq);
1289 }
1290 
1291 static void
1292 vtcon_port_in(struct vtcon_port *port)
1293 {
1294 	struct virtqueue *vq;
1295 	struct tty *tp;
1296 	char *buf;
1297 	uint32_t len;
1298 	int i, deq;
1299 
1300 	tp = port->vtcport_tty;
1301 	vq = port->vtcport_invq;
1302 
1303 again:
1304 	deq = 0;
1305 
1306 	while ((buf = virtqueue_dequeue(vq, &len)) != NULL) {
1307 		for (i = 0; i < len; i++) {
1308 #if defined(KDB)
1309 			if (port->vtcport_flags & VTCON_PORT_FLAG_CONSOLE)
1310 				kdb_alt_break(buf[i],
1311 				    &port->vtcport_alt_break_state);
1312 #endif
1313 			ttydisc_rint(tp, buf[i], 0);
1314 		}
1315 		vtcon_port_requeue_buf(port, buf);
1316 		deq++;
1317 	}
1318 	ttydisc_rint_done(tp);
1319 
1320 	if (deq > 0)
1321 		virtqueue_notify(vq);
1322 
1323 	if (virtqueue_enable_intr(vq) != 0)
1324 		goto again;
1325 }
1326 
1327 static void
1328 vtcon_port_intr(void *scportx)
1329 {
1330 	struct vtcon_softc_port *scport;
1331 	struct vtcon_softc *sc;
1332 	struct vtcon_port *port;
1333 
1334 	scport = scportx;
1335 	sc = scport->vcsp_sc;
1336 
1337 	VTCON_LOCK(sc);
1338 	port = scport->vcsp_port;
1339 	if (port == NULL) {
1340 		VTCON_UNLOCK(sc);
1341 		return;
1342 	}
1343 	VTCON_PORT_LOCK(port);
1344 	VTCON_UNLOCK(sc);
1345 	if ((port->vtcport_flags & VTCON_PORT_FLAG_GONE) == 0)
1346 		vtcon_port_in(port);
1347 	VTCON_PORT_UNLOCK(port);
1348 }
1349 
1350 static void
1351 vtcon_port_out(struct vtcon_port *port, void *buf, int bufsize)
1352 {
1353 	struct sglist_seg segs[2];
1354 	struct sglist sg;
1355 	struct virtqueue *vq;
1356 	int error;
1357 
1358 	vq = port->vtcport_outvq;
1359 	KASSERT(virtqueue_empty(vq),
1360 	    ("%s: port %p out virtqueue not emtpy", __func__, port));
1361 
1362 	sglist_init(&sg, 2, segs);
1363 	error = sglist_append(&sg, buf, bufsize);
1364 	KASSERT(error == 0, ("%s: error %d adding buffer to sglist",
1365 	    __func__, error));
1366 
1367 	error = virtqueue_enqueue(vq, buf, &sg, sg.sg_nseg, 0);
1368 	if (error == 0) {
1369 		virtqueue_notify(vq);
1370 		virtqueue_poll(vq, NULL);
1371 	}
1372 }
1373 
1374 static void
1375 vtcon_port_submit_event(struct vtcon_port *port, uint16_t event,
1376     uint16_t value)
1377 {
1378 	struct vtcon_softc *sc;
1379 
1380 	sc = port->vtcport_sc;
1381 
1382 	vtcon_ctrl_send_control(sc, port->vtcport_id, event, value);
1383 }
1384 
1385 static int
1386 vtcon_tty_open(struct tty *tp)
1387 {
1388 	struct vtcon_port *port;
1389 
1390 	port = tty_softc(tp);
1391 
1392 	if (port->vtcport_flags & VTCON_PORT_FLAG_GONE)
1393 		return (ENXIO);
1394 
1395 	vtcon_port_submit_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
1396 
1397 	return (0);
1398 }
1399 
1400 static void
1401 vtcon_tty_close(struct tty *tp)
1402 {
1403 	struct vtcon_port *port;
1404 
1405 	port = tty_softc(tp);
1406 
1407 	if (port->vtcport_flags & VTCON_PORT_FLAG_GONE)
1408 		return;
1409 
1410 	vtcon_port_submit_event(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
1411 }
1412 
1413 static void
1414 vtcon_tty_outwakeup(struct tty *tp)
1415 {
1416 	struct vtcon_port *port;
1417 	char buf[VTCON_BULK_BUFSZ];
1418 	int len;
1419 
1420 	port = tty_softc(tp);
1421 
1422 	if (port->vtcport_flags & VTCON_PORT_FLAG_GONE)
1423 		return;
1424 
1425 	while ((len = ttydisc_getc(tp, buf, sizeof(buf))) != 0)
1426 		vtcon_port_out(port, buf, len);
1427 }
1428 
1429 static void
1430 vtcon_tty_free(void *xport)
1431 {
1432 	struct vtcon_port *port;
1433 
1434 	port = xport;
1435 
1436 	vtcon_port_destroy(port);
1437 	atomic_subtract_int(&vtcon_pending_free, 1);
1438 }
1439 
1440 static void
1441 vtcon_get_console_size(struct vtcon_softc *sc, uint16_t *cols, uint16_t *rows)
1442 {
1443 	struct virtio_console_config concfg;
1444 
1445 	KASSERT(sc->vtcon_flags & VTCON_FLAG_SIZE,
1446 	    ("%s: size feature not negotiated", __func__));
1447 
1448 	vtcon_read_config(sc, &concfg);
1449 
1450 	*cols = concfg.cols;
1451 	*rows = concfg.rows;
1452 }
1453 
1454 static void
1455 vtcon_enable_interrupts(struct vtcon_softc *sc)
1456 {
1457 	struct vtcon_softc_port *scport;
1458 	struct vtcon_port *port;
1459 	int i;
1460 
1461 	VTCON_LOCK(sc);
1462 
1463 	if (sc->vtcon_flags & VTCON_FLAG_MULTIPORT)
1464 		virtqueue_enable_intr(sc->vtcon_ctrl_rxvq);
1465 
1466 	for (i = 0; i < sc->vtcon_max_ports; i++) {
1467 		scport = &sc->vtcon_ports[i];
1468 
1469 		port = scport->vcsp_port;
1470 		if (port == NULL)
1471 			continue;
1472 
1473 		VTCON_PORT_LOCK(port);
1474 		vtcon_port_enable_intr(port);
1475 		VTCON_PORT_UNLOCK(port);
1476 	}
1477 
1478 	VTCON_UNLOCK(sc);
1479 }
1480 
1481 static void
1482 vtcon_disable_interrupts(struct vtcon_softc *sc)
1483 {
1484 	struct vtcon_softc_port *scport;
1485 	struct vtcon_port *port;
1486 	int i;
1487 
1488 	VTCON_LOCK_ASSERT(sc);
1489 
1490 	if (sc->vtcon_flags & VTCON_FLAG_MULTIPORT)
1491 		virtqueue_disable_intr(sc->vtcon_ctrl_rxvq);
1492 
1493 	for (i = 0; i < sc->vtcon_max_ports; i++) {
1494 		scport = &sc->vtcon_ports[i];
1495 
1496 		port = scport->vcsp_port;
1497 		if (port == NULL)
1498 			continue;
1499 
1500 		VTCON_PORT_LOCK(port);
1501 		vtcon_port_disable_intr(port);
1502 		VTCON_PORT_UNLOCK(port);
1503 	}
1504 }
1505