xref: /freebsd/sys/dev/virtio/scsi/virtio_scsi.c (revision 397e83df75e0fcd0d3fcb95ae4d794cb7600fc89)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2012, Bryan Venteicher <bryanv@FreeBSD.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice unmodified, this list of conditions, and the following
12  *    disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 /* Driver for VirtIO SCSI devices. */
30 
31 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/kernel.h>
34 #include <sys/kthread.h>
35 #include <sys/malloc.h>
36 #include <sys/module.h>
37 #include <sys/sglist.h>
38 #include <sys/sysctl.h>
39 #include <sys/lock.h>
40 #include <sys/mutex.h>
41 #include <sys/callout.h>
42 #include <sys/queue.h>
43 #include <sys/sbuf.h>
44 
45 #include <machine/stdarg.h>
46 
47 #include <machine/bus.h>
48 #include <machine/resource.h>
49 #include <sys/bus.h>
50 #include <sys/rman.h>
51 
52 #include <cam/cam.h>
53 #include <cam/cam_ccb.h>
54 #include <cam/cam_sim.h>
55 #include <cam/cam_periph.h>
56 #include <cam/cam_xpt_sim.h>
57 #include <cam/cam_debug.h>
58 #include <cam/scsi/scsi_all.h>
59 #include <cam/scsi/scsi_message.h>
60 
61 #include <dev/virtio/virtio.h>
62 #include <dev/virtio/virtqueue.h>
63 #include <dev/virtio/scsi/virtio_scsi.h>
64 #include <dev/virtio/scsi/virtio_scsivar.h>
65 
66 #include "virtio_if.h"
67 
68 static int	vtscsi_modevent(module_t, int, void *);
69 
70 static int	vtscsi_probe(device_t);
71 static int	vtscsi_attach(device_t);
72 static int	vtscsi_detach(device_t);
73 static int	vtscsi_suspend(device_t);
74 static int	vtscsi_resume(device_t);
75 
76 static int	vtscsi_negotiate_features(struct vtscsi_softc *);
77 static int	vtscsi_setup_features(struct vtscsi_softc *);
78 static void	vtscsi_read_config(struct vtscsi_softc *,
79 		    struct virtio_scsi_config *);
80 static int	vtscsi_maximum_segments(struct vtscsi_softc *, int);
81 static int	vtscsi_alloc_virtqueues(struct vtscsi_softc *);
82 static void	vtscsi_check_sizes(struct vtscsi_softc *);
83 static void	vtscsi_write_device_config(struct vtscsi_softc *);
84 static int	vtscsi_reinit(struct vtscsi_softc *);
85 
86 static int	vtscsi_alloc_cam(struct vtscsi_softc *);
87 static int	vtscsi_register_cam(struct vtscsi_softc *);
88 static void	vtscsi_free_cam(struct vtscsi_softc *);
89 static void	vtscsi_cam_async(void *, uint32_t, struct cam_path *, void *);
90 static int	vtscsi_register_async(struct vtscsi_softc *);
91 static void	vtscsi_deregister_async(struct vtscsi_softc *);
92 static void	vtscsi_cam_action(struct cam_sim *, union ccb *);
93 static void	vtscsi_cam_poll(struct cam_sim *);
94 
95 static void	vtscsi_cam_scsi_io(struct vtscsi_softc *, struct cam_sim *,
96 		    union ccb *);
97 static void	vtscsi_cam_get_tran_settings(struct vtscsi_softc *,
98 		    union ccb *);
99 static void	vtscsi_cam_reset_bus(struct vtscsi_softc *, union ccb *);
100 static void	vtscsi_cam_reset_dev(struct vtscsi_softc *, union ccb *);
101 static void	vtscsi_cam_abort(struct vtscsi_softc *, union ccb *);
102 static void	vtscsi_cam_path_inquiry(struct vtscsi_softc *,
103 		    struct cam_sim *, union ccb *);
104 
105 static int	vtscsi_sg_append_scsi_buf(struct vtscsi_softc *,
106 		    struct sglist *, struct ccb_scsiio *);
107 static int	vtscsi_fill_scsi_cmd_sglist(struct vtscsi_softc *,
108 		    struct vtscsi_request *, int *, int *);
109 static int	vtscsi_execute_scsi_cmd(struct vtscsi_softc *,
110 		    struct vtscsi_request *);
111 static int	vtscsi_start_scsi_cmd(struct vtscsi_softc *, union ccb *);
112 static void	vtscsi_complete_abort_timedout_scsi_cmd(struct vtscsi_softc *,
113 		    struct vtscsi_request *);
114 static int	vtscsi_abort_timedout_scsi_cmd(struct vtscsi_softc *,
115 		    struct vtscsi_request *);
116 static void	vtscsi_timedout_scsi_cmd(void *);
117 static cam_status vtscsi_scsi_cmd_cam_status(struct virtio_scsi_cmd_resp *);
118 static cam_status vtscsi_complete_scsi_cmd_response(struct vtscsi_softc *,
119 		    struct ccb_scsiio *, struct virtio_scsi_cmd_resp *);
120 static void	vtscsi_complete_scsi_cmd(struct vtscsi_softc *,
121 		    struct vtscsi_request *);
122 
123 static void	vtscsi_poll_ctrl_req(struct vtscsi_softc *,
124 		    struct vtscsi_request *);
125 static int	vtscsi_execute_ctrl_req(struct vtscsi_softc *,
126 		    struct vtscsi_request *, struct sglist *, int, int, int);
127 static void	vtscsi_complete_abort_task_cmd(struct vtscsi_softc *c,
128 		    struct vtscsi_request *);
129 static int	vtscsi_execute_abort_task_cmd(struct vtscsi_softc *,
130 		    struct vtscsi_request *);
131 static int	vtscsi_execute_reset_dev_cmd(struct vtscsi_softc *,
132 		    struct vtscsi_request *);
133 
134 static void	vtscsi_get_request_lun(uint8_t [], target_id_t *, lun_id_t *);
135 static void	vtscsi_set_request_lun(struct ccb_hdr *, uint8_t []);
136 static void	vtscsi_init_scsi_cmd_req(struct vtscsi_softc *,
137 		    struct ccb_scsiio *, struct virtio_scsi_cmd_req *);
138 static void	vtscsi_init_ctrl_tmf_req(struct vtscsi_softc *, struct ccb_hdr *,
139 		    uint32_t, uintptr_t, struct virtio_scsi_ctrl_tmf_req *);
140 
141 static void	vtscsi_freeze_simq(struct vtscsi_softc *, int);
142 static int	vtscsi_thaw_simq(struct vtscsi_softc *, int);
143 
144 static void	vtscsi_announce(struct vtscsi_softc *, uint32_t, target_id_t,
145 		    lun_id_t);
146 static void	vtscsi_execute_rescan(struct vtscsi_softc *, target_id_t,
147 		    lun_id_t);
148 static void	vtscsi_execute_rescan_bus(struct vtscsi_softc *);
149 
150 static void	vtscsi_handle_event(struct vtscsi_softc *,
151 		    struct virtio_scsi_event *);
152 static int	vtscsi_enqueue_event_buf(struct vtscsi_softc *,
153 		    struct virtio_scsi_event *);
154 static int	vtscsi_init_event_vq(struct vtscsi_softc *);
155 static void	vtscsi_reinit_event_vq(struct vtscsi_softc *);
156 static void	vtscsi_drain_event_vq(struct vtscsi_softc *);
157 
158 static void	vtscsi_complete_vqs_locked(struct vtscsi_softc *);
159 static void	vtscsi_complete_vqs(struct vtscsi_softc *);
160 static void	vtscsi_drain_vqs(struct vtscsi_softc *);
161 static void	vtscsi_cancel_request(struct vtscsi_softc *,
162 		    struct vtscsi_request *);
163 static void	vtscsi_drain_vq(struct vtscsi_softc *, struct virtqueue *);
164 static void	vtscsi_stop(struct vtscsi_softc *);
165 static int	vtscsi_reset_bus(struct vtscsi_softc *);
166 
167 static void	vtscsi_init_request(struct vtscsi_softc *,
168 		    struct vtscsi_request *);
169 static int	vtscsi_alloc_requests(struct vtscsi_softc *);
170 static void	vtscsi_free_requests(struct vtscsi_softc *);
171 static void	vtscsi_enqueue_request(struct vtscsi_softc *,
172 		    struct vtscsi_request *);
173 static struct vtscsi_request * vtscsi_dequeue_request(struct vtscsi_softc *);
174 
175 static void	vtscsi_complete_request(struct vtscsi_request *);
176 static void	vtscsi_complete_vq(struct vtscsi_softc *, struct virtqueue *);
177 
178 static void	vtscsi_control_vq_intr(void *);
179 static void	vtscsi_event_vq_intr(void *);
180 static void	vtscsi_request_vq_intr(void *);
181 static void	vtscsi_disable_vqs_intr(struct vtscsi_softc *);
182 static void	vtscsi_enable_vqs_intr(struct vtscsi_softc *);
183 
184 static void	vtscsi_get_tunables(struct vtscsi_softc *);
185 static void	vtscsi_setup_sysctl(struct vtscsi_softc *);
186 
187 static void	vtscsi_printf_req(struct vtscsi_request *, const char *,
188 		    const char *, ...);
189 
190 #define vtscsi_modern(_sc) (((_sc)->vtscsi_features & VIRTIO_F_VERSION_1) != 0)
191 #define vtscsi_htog16(_sc, _val)	virtio_htog16(vtscsi_modern(_sc), _val)
192 #define vtscsi_htog32(_sc, _val)	virtio_htog32(vtscsi_modern(_sc), _val)
193 #define vtscsi_htog64(_sc, _val)	virtio_htog64(vtscsi_modern(_sc), _val)
194 #define vtscsi_gtoh16(_sc, _val)	virtio_gtoh16(vtscsi_modern(_sc), _val)
195 #define vtscsi_gtoh32(_sc, _val)	virtio_gtoh32(vtscsi_modern(_sc), _val)
196 #define vtscsi_gtoh64(_sc, _val)	virtio_gtoh64(vtscsi_modern(_sc), _val)
197 
198 /* Global tunables. */
199 /*
200  * The current QEMU VirtIO SCSI implementation does not cancel in-flight
201  * IO during virtio_stop(). So in-flight requests still complete after the
202  * device reset. We would have to wait for all the in-flight IO to complete,
203  * which defeats the typical purpose of a bus reset. We could simulate the
204  * bus reset with either I_T_NEXUS_RESET of all the targets, or with
205  * LOGICAL_UNIT_RESET of all the LUNs (assuming there is space in the
206  * control virtqueue). But this isn't very useful if things really go off
207  * the rails, so default to disabled for now.
208  */
209 static int vtscsi_bus_reset_disable = 1;
210 TUNABLE_INT("hw.vtscsi.bus_reset_disable", &vtscsi_bus_reset_disable);
211 
212 static struct virtio_feature_desc vtscsi_feature_desc[] = {
213 	{ VIRTIO_SCSI_F_INOUT,		"InOut"		},
214 	{ VIRTIO_SCSI_F_HOTPLUG,	"Hotplug"	},
215 	{ VIRTIO_SCSI_F_CHANGE,		"ChangeEvent"	},
216 	{ VIRTIO_SCSI_F_T10_PI, 	"T10PI"		},
217 
218 	{ 0, NULL }
219 };
220 
221 static device_method_t vtscsi_methods[] = {
222 	/* Device methods. */
223 	DEVMETHOD(device_probe,		vtscsi_probe),
224 	DEVMETHOD(device_attach,	vtscsi_attach),
225 	DEVMETHOD(device_detach,	vtscsi_detach),
226 	DEVMETHOD(device_suspend,	vtscsi_suspend),
227 	DEVMETHOD(device_resume,	vtscsi_resume),
228 
229 	DEVMETHOD_END
230 };
231 
232 static driver_t vtscsi_driver = {
233 	"vtscsi",
234 	vtscsi_methods,
235 	sizeof(struct vtscsi_softc)
236 };
237 
238 VIRTIO_DRIVER_MODULE(virtio_scsi, vtscsi_driver, vtscsi_modevent, NULL);
239 MODULE_VERSION(virtio_scsi, 1);
240 MODULE_DEPEND(virtio_scsi, virtio, 1, 1, 1);
241 MODULE_DEPEND(virtio_scsi, cam, 1, 1, 1);
242 
243 VIRTIO_SIMPLE_PNPINFO(virtio_scsi, VIRTIO_ID_SCSI, "VirtIO SCSI Adapter");
244 
245 static int
246 vtscsi_modevent(module_t mod, int type, void *unused)
247 {
248 	int error;
249 
250 	switch (type) {
251 	case MOD_LOAD:
252 	case MOD_QUIESCE:
253 	case MOD_UNLOAD:
254 	case MOD_SHUTDOWN:
255 		error = 0;
256 		break;
257 	default:
258 		error = EOPNOTSUPP;
259 		break;
260 	}
261 
262 	return (error);
263 }
264 
265 static int
266 vtscsi_probe(device_t dev)
267 {
268 	return (VIRTIO_SIMPLE_PROBE(dev, virtio_scsi));
269 }
270 
271 static int
272 vtscsi_attach(device_t dev)
273 {
274 	struct vtscsi_softc *sc;
275 	struct virtio_scsi_config scsicfg;
276 	int error;
277 
278 	sc = device_get_softc(dev);
279 	sc->vtscsi_dev = dev;
280 	virtio_set_feature_desc(dev, vtscsi_feature_desc);
281 
282 	VTSCSI_LOCK_INIT(sc, device_get_nameunit(dev));
283 	TAILQ_INIT(&sc->vtscsi_req_free);
284 
285 	vtscsi_get_tunables(sc);
286 	vtscsi_setup_sysctl(sc);
287 
288 	error = vtscsi_setup_features(sc);
289 	if (error) {
290 		device_printf(dev, "cannot setup features\n");
291 		goto fail;
292 	}
293 
294 	vtscsi_read_config(sc, &scsicfg);
295 
296 	sc->vtscsi_max_channel = scsicfg.max_channel;
297 	sc->vtscsi_max_target = scsicfg.max_target;
298 	sc->vtscsi_max_lun = scsicfg.max_lun;
299 	sc->vtscsi_event_buf_size = scsicfg.event_info_size;
300 
301 	vtscsi_write_device_config(sc);
302 
303 	sc->vtscsi_max_nsegs = vtscsi_maximum_segments(sc, scsicfg.seg_max);
304 	sc->vtscsi_sglist = sglist_alloc(sc->vtscsi_max_nsegs, M_NOWAIT);
305 	if (sc->vtscsi_sglist == NULL) {
306 		error = ENOMEM;
307 		device_printf(dev, "cannot allocate sglist\n");
308 		goto fail;
309 	}
310 
311 	error = vtscsi_alloc_virtqueues(sc);
312 	if (error) {
313 		device_printf(dev, "cannot allocate virtqueues\n");
314 		goto fail;
315 	}
316 
317 	vtscsi_check_sizes(sc);
318 
319 	error = vtscsi_init_event_vq(sc);
320 	if (error) {
321 		device_printf(dev, "cannot populate the eventvq\n");
322 		goto fail;
323 	}
324 
325 	error = vtscsi_alloc_requests(sc);
326 	if (error) {
327 		device_printf(dev, "cannot allocate requests\n");
328 		goto fail;
329 	}
330 
331 	error = vtscsi_alloc_cam(sc);
332 	if (error) {
333 		device_printf(dev, "cannot allocate CAM structures\n");
334 		goto fail;
335 	}
336 
337 	error = virtio_setup_intr(dev, INTR_TYPE_CAM);
338 	if (error) {
339 		device_printf(dev, "cannot setup virtqueue interrupts\n");
340 		goto fail;
341 	}
342 
343 	vtscsi_enable_vqs_intr(sc);
344 
345 	/*
346 	 * Register with CAM after interrupts are enabled so we will get
347 	 * notified of the probe responses.
348 	 */
349 	error = vtscsi_register_cam(sc);
350 	if (error) {
351 		device_printf(dev, "cannot register with CAM\n");
352 		goto fail;
353 	}
354 
355 fail:
356 	if (error)
357 		vtscsi_detach(dev);
358 
359 	return (error);
360 }
361 
362 static int
363 vtscsi_detach(device_t dev)
364 {
365 	struct vtscsi_softc *sc;
366 
367 	sc = device_get_softc(dev);
368 
369 	VTSCSI_LOCK(sc);
370 	sc->vtscsi_flags |= VTSCSI_FLAG_DETACH;
371 	if (device_is_attached(dev))
372 		vtscsi_stop(sc);
373 	VTSCSI_UNLOCK(sc);
374 
375 	vtscsi_complete_vqs(sc);
376 	vtscsi_drain_vqs(sc);
377 
378 	vtscsi_free_cam(sc);
379 	vtscsi_free_requests(sc);
380 
381 	if (sc->vtscsi_sglist != NULL) {
382 		sglist_free(sc->vtscsi_sglist);
383 		sc->vtscsi_sglist = NULL;
384 	}
385 
386 	VTSCSI_LOCK_DESTROY(sc);
387 
388 	return (0);
389 }
390 
391 static int
392 vtscsi_suspend(device_t dev)
393 {
394 
395 	return (0);
396 }
397 
398 static int
399 vtscsi_resume(device_t dev)
400 {
401 
402 	return (0);
403 }
404 
405 static int
406 vtscsi_negotiate_features(struct vtscsi_softc *sc)
407 {
408 	device_t dev;
409 	uint64_t features;
410 
411 	dev = sc->vtscsi_dev;
412 	features = VTSCSI_FEATURES;
413 
414 	sc->vtscsi_features = virtio_negotiate_features(dev, features);
415 	return (virtio_finalize_features(dev));
416 }
417 
418 static int
419 vtscsi_setup_features(struct vtscsi_softc *sc)
420 {
421 	device_t dev;
422 	int error;
423 
424 	dev = sc->vtscsi_dev;
425 
426 	error = vtscsi_negotiate_features(sc);
427 	if (error)
428 		return (error);
429 
430 	if (virtio_with_feature(dev, VIRTIO_RING_F_INDIRECT_DESC))
431 		sc->vtscsi_flags |= VTSCSI_FLAG_INDIRECT;
432 	if (virtio_with_feature(dev, VIRTIO_SCSI_F_INOUT))
433 		sc->vtscsi_flags |= VTSCSI_FLAG_BIDIRECTIONAL;
434 	if (virtio_with_feature(dev, VIRTIO_SCSI_F_HOTPLUG))
435 		sc->vtscsi_flags |= VTSCSI_FLAG_HOTPLUG;
436 
437 	return (0);
438 }
439 
440 #define VTSCSI_GET_CONFIG(_dev, _field, _cfg)			\
441 	virtio_read_device_config(_dev,				\
442 	    offsetof(struct virtio_scsi_config, _field),	\
443 	    &(_cfg)->_field, sizeof((_cfg)->_field))		\
444 
445 static void
446 vtscsi_read_config(struct vtscsi_softc *sc,
447     struct virtio_scsi_config *scsicfg)
448 {
449 	device_t dev;
450 
451 	dev = sc->vtscsi_dev;
452 
453 	bzero(scsicfg, sizeof(struct virtio_scsi_config));
454 
455 	VTSCSI_GET_CONFIG(dev, num_queues, scsicfg);
456 	VTSCSI_GET_CONFIG(dev, seg_max, scsicfg);
457 	VTSCSI_GET_CONFIG(dev, max_sectors, scsicfg);
458 	VTSCSI_GET_CONFIG(dev, cmd_per_lun, scsicfg);
459 	VTSCSI_GET_CONFIG(dev, event_info_size, scsicfg);
460 	VTSCSI_GET_CONFIG(dev, sense_size, scsicfg);
461 	VTSCSI_GET_CONFIG(dev, cdb_size, scsicfg);
462 	VTSCSI_GET_CONFIG(dev, max_channel, scsicfg);
463 	VTSCSI_GET_CONFIG(dev, max_target, scsicfg);
464 	VTSCSI_GET_CONFIG(dev, max_lun, scsicfg);
465 }
466 
467 #undef VTSCSI_GET_CONFIG
468 
469 static int
470 vtscsi_maximum_segments(struct vtscsi_softc *sc, int seg_max)
471 {
472 	int nsegs;
473 
474 	nsegs = VTSCSI_MIN_SEGMENTS;
475 
476 	if (seg_max > 0) {
477 		nsegs += MIN(seg_max, maxphys / PAGE_SIZE + 1);
478 		if (sc->vtscsi_flags & VTSCSI_FLAG_INDIRECT)
479 			nsegs = MIN(nsegs, VIRTIO_MAX_INDIRECT);
480 	} else
481 		nsegs += 1;
482 
483 	return (nsegs);
484 }
485 
486 static int
487 vtscsi_alloc_virtqueues(struct vtscsi_softc *sc)
488 {
489 	device_t dev;
490 	struct vq_alloc_info vq_info[3];
491 	int nvqs;
492 
493 	dev = sc->vtscsi_dev;
494 	nvqs = 3;
495 
496 	VQ_ALLOC_INFO_INIT(&vq_info[0], 0, vtscsi_control_vq_intr, sc,
497 	    &sc->vtscsi_control_vq, "%s control", device_get_nameunit(dev));
498 
499 	VQ_ALLOC_INFO_INIT(&vq_info[1], 0, vtscsi_event_vq_intr, sc,
500 	    &sc->vtscsi_event_vq, "%s event", device_get_nameunit(dev));
501 
502 	VQ_ALLOC_INFO_INIT(&vq_info[2], sc->vtscsi_max_nsegs,
503 	    vtscsi_request_vq_intr, sc, &sc->vtscsi_request_vq,
504 	    "%s request", device_get_nameunit(dev));
505 
506 	return (virtio_alloc_virtqueues(dev, nvqs, vq_info));
507 }
508 
509 static void
510 vtscsi_check_sizes(struct vtscsi_softc *sc)
511 {
512 	int rqsize;
513 
514 	if ((sc->vtscsi_flags & VTSCSI_FLAG_INDIRECT) == 0) {
515 		/*
516 		 * Ensure the assertions in virtqueue_enqueue(),
517 		 * even if the hypervisor reports a bad seg_max.
518 		 */
519 		rqsize = virtqueue_size(sc->vtscsi_request_vq);
520 		if (sc->vtscsi_max_nsegs > rqsize) {
521 			device_printf(sc->vtscsi_dev,
522 			    "clamping seg_max (%d %d)\n", sc->vtscsi_max_nsegs,
523 			    rqsize);
524 			sc->vtscsi_max_nsegs = rqsize;
525 		}
526 	}
527 }
528 
529 static void
530 vtscsi_write_device_config(struct vtscsi_softc *sc)
531 {
532 
533 	virtio_write_dev_config_4(sc->vtscsi_dev,
534 	    offsetof(struct virtio_scsi_config, sense_size),
535 	    VIRTIO_SCSI_SENSE_SIZE);
536 
537 	/*
538 	 * This is the size in the virtio_scsi_cmd_req structure. Note
539 	 * this value (32) is larger than the maximum CAM CDB size (16).
540 	 */
541 	virtio_write_dev_config_4(sc->vtscsi_dev,
542 	    offsetof(struct virtio_scsi_config, cdb_size),
543 	    VIRTIO_SCSI_CDB_SIZE);
544 }
545 
546 static int
547 vtscsi_reinit(struct vtscsi_softc *sc)
548 {
549 	device_t dev;
550 	int error;
551 
552 	dev = sc->vtscsi_dev;
553 
554 	error = virtio_reinit(dev, sc->vtscsi_features);
555 	if (error == 0) {
556 		vtscsi_write_device_config(sc);
557 		virtio_reinit_complete(dev);
558 		vtscsi_reinit_event_vq(sc);
559 
560 		vtscsi_enable_vqs_intr(sc);
561 	}
562 
563 	vtscsi_dprintf(sc, VTSCSI_TRACE, "error=%d\n", error);
564 
565 	return (error);
566 }
567 
568 static int
569 vtscsi_alloc_cam(struct vtscsi_softc *sc)
570 {
571 	device_t dev;
572 	struct cam_devq *devq;
573 	int openings;
574 
575 	dev = sc->vtscsi_dev;
576 	openings = sc->vtscsi_nrequests - VTSCSI_RESERVED_REQUESTS;
577 
578 	devq = cam_simq_alloc(openings);
579 	if (devq == NULL) {
580 		device_printf(dev, "cannot allocate SIM queue\n");
581 		return (ENOMEM);
582 	}
583 
584 	sc->vtscsi_sim = cam_sim_alloc(vtscsi_cam_action, vtscsi_cam_poll,
585 	    "vtscsi", sc, device_get_unit(dev), VTSCSI_MTX(sc), 1,
586 	    openings, devq);
587 	if (sc->vtscsi_sim == NULL) {
588 		cam_simq_free(devq);
589 		device_printf(dev, "cannot allocate SIM\n");
590 		return (ENOMEM);
591 	}
592 
593 	return (0);
594 }
595 
596 static int
597 vtscsi_register_cam(struct vtscsi_softc *sc)
598 {
599 	device_t dev;
600 	int registered, error;
601 
602 	dev = sc->vtscsi_dev;
603 	registered = 0;
604 
605 	VTSCSI_LOCK(sc);
606 
607 	if (xpt_bus_register(sc->vtscsi_sim, dev, 0) != CAM_SUCCESS) {
608 		error = ENOMEM;
609 		device_printf(dev, "cannot register XPT bus\n");
610 		goto fail;
611 	}
612 
613 	registered = 1;
614 
615 	if (xpt_create_path(&sc->vtscsi_path, NULL,
616 	    cam_sim_path(sc->vtscsi_sim), CAM_TARGET_WILDCARD,
617 	    CAM_LUN_WILDCARD) != CAM_REQ_CMP) {
618 		error = ENOMEM;
619 		device_printf(dev, "cannot create bus path\n");
620 		goto fail;
621 	}
622 
623 	if (vtscsi_register_async(sc) != CAM_REQ_CMP) {
624 		error = EIO;
625 		device_printf(dev, "cannot register async callback\n");
626 		goto fail;
627 	}
628 
629 	VTSCSI_UNLOCK(sc);
630 
631 	return (0);
632 
633 fail:
634 	if (sc->vtscsi_path != NULL) {
635 		xpt_free_path(sc->vtscsi_path);
636 		sc->vtscsi_path = NULL;
637 	}
638 
639 	if (registered != 0)
640 		xpt_bus_deregister(cam_sim_path(sc->vtscsi_sim));
641 
642 	VTSCSI_UNLOCK(sc);
643 
644 	return (error);
645 }
646 
647 static void
648 vtscsi_free_cam(struct vtscsi_softc *sc)
649 {
650 
651 	VTSCSI_LOCK(sc);
652 
653 	if (sc->vtscsi_path != NULL) {
654 		vtscsi_deregister_async(sc);
655 
656 		xpt_free_path(sc->vtscsi_path);
657 		sc->vtscsi_path = NULL;
658 
659 		xpt_bus_deregister(cam_sim_path(sc->vtscsi_sim));
660 	}
661 
662 	if (sc->vtscsi_sim != NULL) {
663 		cam_sim_free(sc->vtscsi_sim, 1);
664 		sc->vtscsi_sim = NULL;
665 	}
666 
667 	VTSCSI_UNLOCK(sc);
668 }
669 
670 static void
671 vtscsi_cam_async(void *cb_arg, uint32_t code, struct cam_path *path, void *arg)
672 {
673 	struct cam_sim *sim;
674 	struct vtscsi_softc *sc;
675 
676 	sim = cb_arg;
677 	sc = cam_sim_softc(sim);
678 
679 	vtscsi_dprintf(sc, VTSCSI_TRACE, "code=%u\n", code);
680 
681 	/*
682 	 * TODO Once QEMU supports event reporting, we should
683 	 *      (un)subscribe to events here.
684 	 */
685 	switch (code) {
686 	case AC_FOUND_DEVICE:
687 		break;
688 	case AC_LOST_DEVICE:
689 		break;
690 	}
691 }
692 
693 static int
694 vtscsi_register_async(struct vtscsi_softc *sc)
695 {
696 	struct ccb_setasync csa;
697 
698 	memset(&csa, 0, sizeof(csa));
699 	xpt_setup_ccb(&csa.ccb_h, sc->vtscsi_path, 5);
700 	csa.ccb_h.func_code = XPT_SASYNC_CB;
701 	csa.event_enable = AC_LOST_DEVICE | AC_FOUND_DEVICE;
702 	csa.callback = vtscsi_cam_async;
703 	csa.callback_arg = sc->vtscsi_sim;
704 
705 	xpt_action((union ccb *) &csa);
706 
707 	return (csa.ccb_h.status);
708 }
709 
710 static void
711 vtscsi_deregister_async(struct vtscsi_softc *sc)
712 {
713 	struct ccb_setasync csa;
714 
715 	memset(&csa, 0, sizeof(csa));
716 	xpt_setup_ccb(&csa.ccb_h, sc->vtscsi_path, 5);
717 	csa.ccb_h.func_code = XPT_SASYNC_CB;
718 	csa.event_enable = 0;
719 	csa.callback = vtscsi_cam_async;
720 	csa.callback_arg = sc->vtscsi_sim;
721 
722 	xpt_action((union ccb *) &csa);
723 }
724 
725 static void
726 vtscsi_cam_action(struct cam_sim *sim, union ccb *ccb)
727 {
728 	struct vtscsi_softc *sc;
729 	struct ccb_hdr *ccbh;
730 
731 	sc = cam_sim_softc(sim);
732 	ccbh = &ccb->ccb_h;
733 
734 	VTSCSI_LOCK_OWNED(sc);
735 
736 	if (sc->vtscsi_flags & VTSCSI_FLAG_DETACH) {
737 		/*
738 		 * The VTSCSI_MTX is briefly dropped between setting
739 		 * VTSCSI_FLAG_DETACH and deregistering with CAM, so
740 		 * drop any CCBs that come in during that window.
741 		 */
742 		ccbh->status = CAM_NO_HBA;
743 		xpt_done(ccb);
744 		return;
745 	}
746 
747 	switch (ccbh->func_code) {
748 	case XPT_SCSI_IO:
749 		vtscsi_cam_scsi_io(sc, sim, ccb);
750 		break;
751 
752 	case XPT_SET_TRAN_SETTINGS:
753 		ccbh->status = CAM_FUNC_NOTAVAIL;
754 		xpt_done(ccb);
755 		break;
756 
757 	case XPT_GET_TRAN_SETTINGS:
758 		vtscsi_cam_get_tran_settings(sc, ccb);
759 		break;
760 
761 	case XPT_RESET_BUS:
762 		vtscsi_cam_reset_bus(sc, ccb);
763 		break;
764 
765 	case XPT_RESET_DEV:
766 		vtscsi_cam_reset_dev(sc, ccb);
767 		break;
768 
769 	case XPT_ABORT:
770 		vtscsi_cam_abort(sc, ccb);
771 		break;
772 
773 	case XPT_CALC_GEOMETRY:
774 		cam_calc_geometry(&ccb->ccg, 1);
775 		xpt_done(ccb);
776 		break;
777 
778 	case XPT_PATH_INQ:
779 		vtscsi_cam_path_inquiry(sc, sim, ccb);
780 		break;
781 
782 	default:
783 		vtscsi_dprintf(sc, VTSCSI_ERROR,
784 		    "invalid ccb=%p func=%#x\n", ccb, ccbh->func_code);
785 
786 		ccbh->status = CAM_REQ_INVALID;
787 		xpt_done(ccb);
788 		break;
789 	}
790 }
791 
792 static void
793 vtscsi_cam_poll(struct cam_sim *sim)
794 {
795 	struct vtscsi_softc *sc;
796 
797 	sc = cam_sim_softc(sim);
798 
799 	vtscsi_complete_vqs_locked(sc);
800 }
801 
802 static void
803 vtscsi_cam_scsi_io(struct vtscsi_softc *sc, struct cam_sim *sim,
804     union ccb *ccb)
805 {
806 	struct ccb_hdr *ccbh;
807 	struct ccb_scsiio *csio;
808 	int error;
809 
810 	ccbh = &ccb->ccb_h;
811 	csio = &ccb->csio;
812 
813 	if (csio->cdb_len > VIRTIO_SCSI_CDB_SIZE) {
814 		error = EINVAL;
815 		ccbh->status = CAM_REQ_INVALID;
816 		goto done;
817 	}
818 
819 	if ((ccbh->flags & CAM_DIR_MASK) == CAM_DIR_BOTH &&
820 	    (sc->vtscsi_flags & VTSCSI_FLAG_BIDIRECTIONAL) == 0) {
821 		error = EINVAL;
822 		ccbh->status = CAM_REQ_INVALID;
823 		goto done;
824 	}
825 
826 	error = vtscsi_start_scsi_cmd(sc, ccb);
827 
828 done:
829 	if (error) {
830 		vtscsi_dprintf(sc, VTSCSI_ERROR,
831 		    "error=%d ccb=%p status=%#x\n", error, ccb, ccbh->status);
832 		xpt_done(ccb);
833 	}
834 }
835 
836 static void
837 vtscsi_cam_get_tran_settings(struct vtscsi_softc *sc, union ccb *ccb)
838 {
839 	struct ccb_trans_settings *cts;
840 	struct ccb_trans_settings_scsi *scsi;
841 
842 	cts = &ccb->cts;
843 	scsi = &cts->proto_specific.scsi;
844 
845 	cts->protocol = PROTO_SCSI;
846 	cts->protocol_version = SCSI_REV_SPC3;
847 	cts->transport = XPORT_SAS;
848 	cts->transport_version = 0;
849 
850 	scsi->valid = CTS_SCSI_VALID_TQ;
851 	scsi->flags = CTS_SCSI_FLAGS_TAG_ENB;
852 
853 	ccb->ccb_h.status = CAM_REQ_CMP;
854 	xpt_done(ccb);
855 }
856 
857 static void
858 vtscsi_cam_reset_bus(struct vtscsi_softc *sc, union ccb *ccb)
859 {
860 	int error;
861 
862 	error = vtscsi_reset_bus(sc);
863 	if (error == 0)
864 		ccb->ccb_h.status = CAM_REQ_CMP;
865 	else
866 		ccb->ccb_h.status = CAM_REQ_CMP_ERR;
867 
868 	vtscsi_dprintf(sc, VTSCSI_TRACE, "error=%d ccb=%p status=%#x\n",
869 	    error, ccb, ccb->ccb_h.status);
870 
871 	xpt_done(ccb);
872 }
873 
874 static void
875 vtscsi_cam_reset_dev(struct vtscsi_softc *sc, union ccb *ccb)
876 {
877 	struct ccb_hdr *ccbh;
878 	struct vtscsi_request *req;
879 	int error;
880 
881 	ccbh = &ccb->ccb_h;
882 
883 	req = vtscsi_dequeue_request(sc);
884 	if (req == NULL) {
885 		error = EAGAIN;
886 		vtscsi_freeze_simq(sc, VTSCSI_REQUEST);
887 		goto fail;
888 	}
889 
890 	req->vsr_ccb = ccb;
891 
892 	error = vtscsi_execute_reset_dev_cmd(sc, req);
893 	if (error == 0)
894 		return;
895 
896 	vtscsi_enqueue_request(sc, req);
897 
898 fail:
899 	vtscsi_dprintf(sc, VTSCSI_ERROR, "error=%d req=%p ccb=%p\n",
900 	    error, req, ccb);
901 
902 	if (error == EAGAIN)
903 		ccbh->status = CAM_RESRC_UNAVAIL;
904 	else
905 		ccbh->status = CAM_REQ_CMP_ERR;
906 
907 	xpt_done(ccb);
908 }
909 
910 static void
911 vtscsi_cam_abort(struct vtscsi_softc *sc, union ccb *ccb)
912 {
913 	struct vtscsi_request *req;
914 	struct ccb_hdr *ccbh;
915 	int error;
916 
917 	ccbh = &ccb->ccb_h;
918 
919 	req = vtscsi_dequeue_request(sc);
920 	if (req == NULL) {
921 		error = EAGAIN;
922 		vtscsi_freeze_simq(sc, VTSCSI_REQUEST);
923 		goto fail;
924 	}
925 
926 	req->vsr_ccb = ccb;
927 
928 	error = vtscsi_execute_abort_task_cmd(sc, req);
929 	if (error == 0)
930 		return;
931 
932 	vtscsi_enqueue_request(sc, req);
933 
934 fail:
935 	vtscsi_dprintf(sc, VTSCSI_ERROR, "error=%d req=%p ccb=%p\n",
936 	    error, req, ccb);
937 
938 	if (error == EAGAIN)
939 		ccbh->status = CAM_RESRC_UNAVAIL;
940 	else
941 		ccbh->status = CAM_REQ_CMP_ERR;
942 
943 	xpt_done(ccb);
944 }
945 
946 static void
947 vtscsi_cam_path_inquiry(struct vtscsi_softc *sc, struct cam_sim *sim,
948     union ccb *ccb)
949 {
950 	device_t dev;
951 	struct ccb_pathinq *cpi;
952 
953 	dev = sc->vtscsi_dev;
954 	cpi = &ccb->cpi;
955 
956 	vtscsi_dprintf(sc, VTSCSI_TRACE, "sim=%p ccb=%p\n", sim, ccb);
957 
958 	cpi->version_num = 1;
959 	cpi->hba_inquiry = PI_TAG_ABLE;
960 	cpi->target_sprt = 0;
961 	cpi->hba_misc = PIM_SEQSCAN | PIM_UNMAPPED;
962 	if (vtscsi_bus_reset_disable != 0)
963 		cpi->hba_misc |= PIM_NOBUSRESET;
964 	cpi->hba_eng_cnt = 0;
965 
966 	cpi->max_target = sc->vtscsi_max_target;
967 	cpi->max_lun = sc->vtscsi_max_lun;
968 	cpi->initiator_id = cpi->max_target + 1;
969 
970 	strlcpy(cpi->sim_vid, "FreeBSD", SIM_IDLEN);
971 	strlcpy(cpi->hba_vid, "VirtIO", HBA_IDLEN);
972 	strlcpy(cpi->dev_name, cam_sim_name(sim), DEV_IDLEN);
973 
974 	cpi->unit_number = cam_sim_unit(sim);
975 	cpi->bus_id = cam_sim_bus(sim);
976 
977 	cpi->base_transfer_speed = 300000;
978 
979 	cpi->protocol = PROTO_SCSI;
980 	cpi->protocol_version = SCSI_REV_SPC3;
981 	cpi->transport = XPORT_SAS;
982 	cpi->transport_version = 0;
983 
984 	cpi->maxio = (sc->vtscsi_max_nsegs - VTSCSI_MIN_SEGMENTS - 1) *
985 	    PAGE_SIZE;
986 
987 	cpi->hba_vendor = virtio_get_vendor(dev);
988 	cpi->hba_device = virtio_get_device(dev);
989 	cpi->hba_subvendor = virtio_get_subvendor(dev);
990 	cpi->hba_subdevice = virtio_get_subdevice(dev);
991 
992 	ccb->ccb_h.status = CAM_REQ_CMP;
993 	xpt_done(ccb);
994 }
995 
996 static int
997 vtscsi_sg_append_scsi_buf(struct vtscsi_softc *sc, struct sglist *sg,
998     struct ccb_scsiio *csio)
999 {
1000 	struct ccb_hdr *ccbh;
1001 	struct bus_dma_segment *dseg;
1002 	int i, error;
1003 
1004 	ccbh = &csio->ccb_h;
1005 	error = 0;
1006 
1007 	switch ((ccbh->flags & CAM_DATA_MASK)) {
1008 	case CAM_DATA_VADDR:
1009 		error = sglist_append(sg, csio->data_ptr, csio->dxfer_len);
1010 		break;
1011 	case CAM_DATA_PADDR:
1012 		error = sglist_append_phys(sg,
1013 		    (vm_paddr_t)(vm_offset_t) csio->data_ptr, csio->dxfer_len);
1014 		break;
1015 	case CAM_DATA_SG:
1016 		for (i = 0; i < csio->sglist_cnt && error == 0; i++) {
1017 			dseg = &((struct bus_dma_segment *)csio->data_ptr)[i];
1018 			error = sglist_append(sg,
1019 			    (void *)(vm_offset_t) dseg->ds_addr, dseg->ds_len);
1020 		}
1021 		break;
1022 	case CAM_DATA_SG_PADDR:
1023 		for (i = 0; i < csio->sglist_cnt && error == 0; i++) {
1024 			dseg = &((struct bus_dma_segment *)csio->data_ptr)[i];
1025 			error = sglist_append_phys(sg,
1026 			    (vm_paddr_t) dseg->ds_addr, dseg->ds_len);
1027 		}
1028 		break;
1029 	case CAM_DATA_BIO:
1030 		error = sglist_append_bio(sg, (struct bio *) csio->data_ptr);
1031 		break;
1032 	default:
1033 		error = EINVAL;
1034 		break;
1035 	}
1036 
1037 	return (error);
1038 }
1039 
1040 static int
1041 vtscsi_fill_scsi_cmd_sglist(struct vtscsi_softc *sc, struct vtscsi_request *req,
1042     int *readable, int *writable)
1043 {
1044 	struct sglist *sg;
1045 	struct ccb_hdr *ccbh;
1046 	struct ccb_scsiio *csio;
1047 	struct virtio_scsi_cmd_req *cmd_req;
1048 	struct virtio_scsi_cmd_resp *cmd_resp;
1049 	int error;
1050 
1051 	sg = sc->vtscsi_sglist;
1052 	csio = &req->vsr_ccb->csio;
1053 	ccbh = &csio->ccb_h;
1054 	cmd_req = &req->vsr_cmd_req;
1055 	cmd_resp = &req->vsr_cmd_resp;
1056 
1057 	sglist_reset(sg);
1058 
1059 	sglist_append(sg, cmd_req, sizeof(struct virtio_scsi_cmd_req));
1060 	if ((ccbh->flags & CAM_DIR_MASK) == CAM_DIR_OUT) {
1061 		error = vtscsi_sg_append_scsi_buf(sc, sg, csio);
1062 		/* At least one segment must be left for the response. */
1063 		if (error || sg->sg_nseg == sg->sg_maxseg)
1064 			goto fail;
1065 	}
1066 
1067 	*readable = sg->sg_nseg;
1068 
1069 	sglist_append(sg, cmd_resp, sizeof(struct virtio_scsi_cmd_resp));
1070 	if ((ccbh->flags & CAM_DIR_MASK) == CAM_DIR_IN) {
1071 		error = vtscsi_sg_append_scsi_buf(sc, sg, csio);
1072 		if (error)
1073 			goto fail;
1074 	}
1075 
1076 	*writable = sg->sg_nseg - *readable;
1077 
1078 	vtscsi_dprintf(sc, VTSCSI_TRACE, "req=%p ccb=%p readable=%d "
1079 	    "writable=%d\n", req, ccbh, *readable, *writable);
1080 
1081 	return (0);
1082 
1083 fail:
1084 	/*
1085 	 * This should never happen unless maxio was incorrectly set.
1086 	 */
1087 	vtscsi_set_ccb_status(ccbh, CAM_REQ_TOO_BIG, 0);
1088 
1089 	vtscsi_dprintf(sc, VTSCSI_ERROR, "error=%d req=%p ccb=%p "
1090 	    "nseg=%d maxseg=%d\n",
1091 	    error, req, ccbh, sg->sg_nseg, sg->sg_maxseg);
1092 
1093 	return (EFBIG);
1094 }
1095 
1096 static int
1097 vtscsi_execute_scsi_cmd(struct vtscsi_softc *sc, struct vtscsi_request *req)
1098 {
1099 	struct sglist *sg;
1100 	struct virtqueue *vq;
1101 	struct ccb_scsiio *csio;
1102 	struct ccb_hdr *ccbh;
1103 	struct virtio_scsi_cmd_req *cmd_req;
1104 	struct virtio_scsi_cmd_resp *cmd_resp;
1105 	int readable, writable, error;
1106 
1107 	sg = sc->vtscsi_sglist;
1108 	vq = sc->vtscsi_request_vq;
1109 	csio = &req->vsr_ccb->csio;
1110 	ccbh = &csio->ccb_h;
1111 	cmd_req = &req->vsr_cmd_req;
1112 	cmd_resp = &req->vsr_cmd_resp;
1113 
1114 	vtscsi_init_scsi_cmd_req(sc, csio, cmd_req);
1115 
1116 	error = vtscsi_fill_scsi_cmd_sglist(sc, req, &readable, &writable);
1117 	if (error)
1118 		return (error);
1119 
1120 	req->vsr_complete = vtscsi_complete_scsi_cmd;
1121 	cmd_resp->response = -1;
1122 
1123 	error = virtqueue_enqueue(vq, req, sg, readable, writable);
1124 	if (error) {
1125 		vtscsi_dprintf(sc, VTSCSI_ERROR,
1126 		    "enqueue error=%d req=%p ccb=%p\n", error, req, ccbh);
1127 
1128 		ccbh->status = CAM_REQUEUE_REQ;
1129 		vtscsi_freeze_simq(sc, VTSCSI_REQUEST_VQ);
1130 		return (error);
1131 	}
1132 
1133 	ccbh->status |= CAM_SIM_QUEUED;
1134 	ccbh->ccbh_vtscsi_req = req;
1135 
1136 	virtqueue_notify(vq);
1137 
1138 	if (ccbh->timeout != CAM_TIME_INFINITY) {
1139 		req->vsr_flags |= VTSCSI_REQ_FLAG_TIMEOUT_SET;
1140 		callout_reset_sbt(&req->vsr_callout, SBT_1MS * ccbh->timeout,
1141 		    0, vtscsi_timedout_scsi_cmd, req, 0);
1142 	}
1143 
1144 	vtscsi_dprintf_req(req, VTSCSI_TRACE, "enqueued req=%p ccb=%p\n",
1145 	    req, ccbh);
1146 
1147 	return (0);
1148 }
1149 
1150 static int
1151 vtscsi_start_scsi_cmd(struct vtscsi_softc *sc, union ccb *ccb)
1152 {
1153 	struct vtscsi_request *req;
1154 	int error;
1155 
1156 	req = vtscsi_dequeue_request(sc);
1157 	if (req == NULL) {
1158 		ccb->ccb_h.status = CAM_REQUEUE_REQ;
1159 		vtscsi_freeze_simq(sc, VTSCSI_REQUEST);
1160 		return (ENOBUFS);
1161 	}
1162 
1163 	req->vsr_ccb = ccb;
1164 
1165 	error = vtscsi_execute_scsi_cmd(sc, req);
1166 	if (error)
1167 		vtscsi_enqueue_request(sc, req);
1168 
1169 	return (error);
1170 }
1171 
1172 static void
1173 vtscsi_complete_abort_timedout_scsi_cmd(struct vtscsi_softc *sc,
1174     struct vtscsi_request *req)
1175 {
1176 	struct virtio_scsi_ctrl_tmf_resp *tmf_resp;
1177 	struct vtscsi_request *to_req;
1178 	uint8_t response;
1179 
1180 	tmf_resp = &req->vsr_tmf_resp;
1181 	response = tmf_resp->response;
1182 	to_req = req->vsr_timedout_req;
1183 
1184 	vtscsi_dprintf(sc, VTSCSI_TRACE, "req=%p to_req=%p response=%d\n",
1185 	    req, to_req, response);
1186 
1187 	vtscsi_enqueue_request(sc, req);
1188 
1189 	/*
1190 	 * The timedout request could have completed between when the
1191 	 * abort task was sent and when the host processed it.
1192 	 */
1193 	if (to_req->vsr_state != VTSCSI_REQ_STATE_TIMEDOUT)
1194 		return;
1195 
1196 	/* The timedout request was successfully aborted. */
1197 	if (response == VIRTIO_SCSI_S_FUNCTION_COMPLETE)
1198 		return;
1199 
1200 	/* Don't bother if the device is going away. */
1201 	if (sc->vtscsi_flags & VTSCSI_FLAG_DETACH)
1202 		return;
1203 
1204 	/* The timedout request will be aborted by the reset. */
1205 	if (sc->vtscsi_flags & VTSCSI_FLAG_RESET)
1206 		return;
1207 
1208 	vtscsi_reset_bus(sc);
1209 }
1210 
1211 static int
1212 vtscsi_abort_timedout_scsi_cmd(struct vtscsi_softc *sc,
1213     struct vtscsi_request *to_req)
1214 {
1215 	struct sglist *sg;
1216 	struct ccb_hdr *to_ccbh;
1217 	struct vtscsi_request *req;
1218 	struct virtio_scsi_ctrl_tmf_req *tmf_req;
1219 	struct virtio_scsi_ctrl_tmf_resp *tmf_resp;
1220 	int error;
1221 
1222 	sg = sc->vtscsi_sglist;
1223 	to_ccbh = &to_req->vsr_ccb->ccb_h;
1224 
1225 	req = vtscsi_dequeue_request(sc);
1226 	if (req == NULL) {
1227 		error = ENOBUFS;
1228 		goto fail;
1229 	}
1230 
1231 	tmf_req = &req->vsr_tmf_req;
1232 	tmf_resp = &req->vsr_tmf_resp;
1233 
1234 	vtscsi_init_ctrl_tmf_req(sc, to_ccbh, VIRTIO_SCSI_T_TMF_ABORT_TASK,
1235 	    (uintptr_t) to_ccbh, tmf_req);
1236 
1237 	sglist_reset(sg);
1238 	sglist_append(sg, tmf_req, sizeof(struct virtio_scsi_ctrl_tmf_req));
1239 	sglist_append(sg, tmf_resp, sizeof(struct virtio_scsi_ctrl_tmf_resp));
1240 
1241 	req->vsr_timedout_req = to_req;
1242 	req->vsr_complete = vtscsi_complete_abort_timedout_scsi_cmd;
1243 	tmf_resp->response = -1;
1244 
1245 	error = vtscsi_execute_ctrl_req(sc, req, sg, 1, 1,
1246 	    VTSCSI_EXECUTE_ASYNC);
1247 	if (error == 0)
1248 		return (0);
1249 
1250 	vtscsi_enqueue_request(sc, req);
1251 
1252 fail:
1253 	vtscsi_dprintf(sc, VTSCSI_ERROR, "error=%d req=%p "
1254 	    "timedout req=%p ccb=%p\n", error, req, to_req, to_ccbh);
1255 
1256 	return (error);
1257 }
1258 
1259 static void
1260 vtscsi_timedout_scsi_cmd(void *xreq)
1261 {
1262 	struct vtscsi_softc *sc;
1263 	struct vtscsi_request *to_req;
1264 
1265 	to_req = xreq;
1266 	sc = to_req->vsr_softc;
1267 
1268 	vtscsi_dprintf(sc, VTSCSI_INFO, "timedout req=%p ccb=%p state=%#x\n",
1269 	    to_req, to_req->vsr_ccb, to_req->vsr_state);
1270 
1271 	/* Don't bother if the device is going away. */
1272 	if (sc->vtscsi_flags & VTSCSI_FLAG_DETACH)
1273 		return;
1274 
1275 	/*
1276 	 * Bail if the request is not in use. We likely raced when
1277 	 * stopping the callout handler or it has already been aborted.
1278 	 */
1279 	if (to_req->vsr_state != VTSCSI_REQ_STATE_INUSE ||
1280 	    (to_req->vsr_flags & VTSCSI_REQ_FLAG_TIMEOUT_SET) == 0)
1281 		return;
1282 
1283 	/*
1284 	 * Complete the request queue in case the timedout request is
1285 	 * actually just pending.
1286 	 */
1287 	vtscsi_complete_vq(sc, sc->vtscsi_request_vq);
1288 	if (to_req->vsr_state == VTSCSI_REQ_STATE_FREE)
1289 		return;
1290 
1291 	sc->vtscsi_stats.scsi_cmd_timeouts++;
1292 	to_req->vsr_state = VTSCSI_REQ_STATE_TIMEDOUT;
1293 
1294 	if (vtscsi_abort_timedout_scsi_cmd(sc, to_req) == 0)
1295 		return;
1296 
1297 	vtscsi_dprintf(sc, VTSCSI_ERROR, "resetting bus\n");
1298 	vtscsi_reset_bus(sc);
1299 }
1300 
1301 static cam_status
1302 vtscsi_scsi_cmd_cam_status(struct virtio_scsi_cmd_resp *cmd_resp)
1303 {
1304 	cam_status status;
1305 
1306 	switch (cmd_resp->response) {
1307 	case VIRTIO_SCSI_S_OK:
1308 		status = CAM_REQ_CMP;
1309 		break;
1310 	case VIRTIO_SCSI_S_OVERRUN:
1311 		status = CAM_DATA_RUN_ERR;
1312 		break;
1313 	case VIRTIO_SCSI_S_ABORTED:
1314 		status = CAM_REQ_ABORTED;
1315 		break;
1316 	case VIRTIO_SCSI_S_BAD_TARGET:
1317 		status = CAM_SEL_TIMEOUT;
1318 		break;
1319 	case VIRTIO_SCSI_S_RESET:
1320 		status = CAM_SCSI_BUS_RESET;
1321 		break;
1322 	case VIRTIO_SCSI_S_BUSY:
1323 		status = CAM_SCSI_BUSY;
1324 		break;
1325 	case VIRTIO_SCSI_S_TRANSPORT_FAILURE:
1326 	case VIRTIO_SCSI_S_TARGET_FAILURE:
1327 	case VIRTIO_SCSI_S_NEXUS_FAILURE:
1328 		status = CAM_SCSI_IT_NEXUS_LOST;
1329 		break;
1330 	default: /* VIRTIO_SCSI_S_FAILURE */
1331 		status = CAM_REQ_CMP_ERR;
1332 		break;
1333 	}
1334 
1335 	return (status);
1336 }
1337 
1338 static cam_status
1339 vtscsi_complete_scsi_cmd_response(struct vtscsi_softc *sc,
1340     struct ccb_scsiio *csio, struct virtio_scsi_cmd_resp *cmd_resp)
1341 {
1342 	uint32_t resp_sense_length;
1343 	cam_status status;
1344 
1345 	csio->scsi_status = cmd_resp->status;
1346 	csio->resid = vtscsi_htog32(sc, cmd_resp->resid);
1347 
1348 	if (csio->scsi_status == SCSI_STATUS_OK)
1349 		status = CAM_REQ_CMP;
1350 	else
1351 		status = CAM_SCSI_STATUS_ERROR;
1352 
1353 	resp_sense_length = vtscsi_htog32(sc, cmd_resp->sense_len);
1354 
1355 	if (resp_sense_length > 0) {
1356 		status |= CAM_AUTOSNS_VALID;
1357 
1358 		if (resp_sense_length < csio->sense_len)
1359 			csio->sense_resid = csio->sense_len - resp_sense_length;
1360 		else
1361 			csio->sense_resid = 0;
1362 
1363 		memcpy(&csio->sense_data, cmd_resp->sense,
1364 		    csio->sense_len - csio->sense_resid);
1365 	}
1366 
1367 	vtscsi_dprintf(sc, status == CAM_REQ_CMP ? VTSCSI_TRACE : VTSCSI_ERROR,
1368 	    "ccb=%p scsi_status=%#x resid=%u sense_resid=%u\n",
1369 	    csio, csio->scsi_status, csio->resid, csio->sense_resid);
1370 
1371 	return (status);
1372 }
1373 
1374 static void
1375 vtscsi_complete_scsi_cmd(struct vtscsi_softc *sc, struct vtscsi_request *req)
1376 {
1377 	struct ccb_hdr *ccbh;
1378 	struct ccb_scsiio *csio;
1379 	struct virtio_scsi_cmd_resp *cmd_resp;
1380 	cam_status status;
1381 
1382 	csio = &req->vsr_ccb->csio;
1383 	ccbh = &csio->ccb_h;
1384 	cmd_resp = &req->vsr_cmd_resp;
1385 
1386 	KASSERT(ccbh->ccbh_vtscsi_req == req,
1387 	    ("ccb %p req mismatch %p/%p", ccbh, ccbh->ccbh_vtscsi_req, req));
1388 
1389 	if (req->vsr_flags & VTSCSI_REQ_FLAG_TIMEOUT_SET)
1390 		callout_stop(&req->vsr_callout);
1391 
1392 	status = vtscsi_scsi_cmd_cam_status(cmd_resp);
1393 	if (status == CAM_REQ_ABORTED) {
1394 		if (req->vsr_state == VTSCSI_REQ_STATE_TIMEDOUT)
1395 			status = CAM_CMD_TIMEOUT;
1396 	} else if (status == CAM_REQ_CMP)
1397 		status = vtscsi_complete_scsi_cmd_response(sc, csio, cmd_resp);
1398 
1399 	if ((status & CAM_STATUS_MASK) != CAM_REQ_CMP) {
1400 		status |= CAM_DEV_QFRZN;
1401 		xpt_freeze_devq(ccbh->path, 1);
1402 	}
1403 
1404 	if (vtscsi_thaw_simq(sc, VTSCSI_REQUEST | VTSCSI_REQUEST_VQ) != 0)
1405 		status |= CAM_RELEASE_SIMQ;
1406 
1407 	vtscsi_dprintf(sc, VTSCSI_TRACE, "req=%p ccb=%p status=%#x\n",
1408 	    req, ccbh, status);
1409 
1410 	ccbh->status = status;
1411 	xpt_done(req->vsr_ccb);
1412 	vtscsi_enqueue_request(sc, req);
1413 }
1414 
1415 static void
1416 vtscsi_poll_ctrl_req(struct vtscsi_softc *sc, struct vtscsi_request *req)
1417 {
1418 
1419 	/* XXX We probably shouldn't poll forever. */
1420 	req->vsr_flags |= VTSCSI_REQ_FLAG_POLLED;
1421 	do
1422 		vtscsi_complete_vq(sc, sc->vtscsi_control_vq);
1423 	while ((req->vsr_flags & VTSCSI_REQ_FLAG_COMPLETE) == 0);
1424 
1425 	req->vsr_flags &= ~VTSCSI_REQ_FLAG_POLLED;
1426 }
1427 
1428 static int
1429 vtscsi_execute_ctrl_req(struct vtscsi_softc *sc, struct vtscsi_request *req,
1430     struct sglist *sg, int readable, int writable, int flag)
1431 {
1432 	struct virtqueue *vq;
1433 	int error;
1434 
1435 	vq = sc->vtscsi_control_vq;
1436 
1437 	MPASS(flag == VTSCSI_EXECUTE_POLL || req->vsr_complete != NULL);
1438 
1439 	error = virtqueue_enqueue(vq, req, sg, readable, writable);
1440 	if (error) {
1441 		/*
1442 		 * Return EAGAIN when the virtqueue does not have enough
1443 		 * descriptors available.
1444 		 */
1445 		if (error == ENOSPC || error == EMSGSIZE)
1446 			error = EAGAIN;
1447 
1448 		return (error);
1449 	}
1450 
1451 	virtqueue_notify(vq);
1452 	if (flag == VTSCSI_EXECUTE_POLL)
1453 		vtscsi_poll_ctrl_req(sc, req);
1454 
1455 	return (0);
1456 }
1457 
1458 static void
1459 vtscsi_complete_abort_task_cmd(struct vtscsi_softc *sc,
1460     struct vtscsi_request *req)
1461 {
1462 	union ccb *ccb;
1463 	struct ccb_hdr *ccbh;
1464 	struct virtio_scsi_ctrl_tmf_resp *tmf_resp;
1465 
1466 	ccb = req->vsr_ccb;
1467 	ccbh = &ccb->ccb_h;
1468 	tmf_resp = &req->vsr_tmf_resp;
1469 
1470 	switch (tmf_resp->response) {
1471 	case VIRTIO_SCSI_S_FUNCTION_COMPLETE:
1472 		ccbh->status = CAM_REQ_CMP;
1473 		break;
1474 	case VIRTIO_SCSI_S_FUNCTION_REJECTED:
1475 		ccbh->status = CAM_UA_ABORT;
1476 		break;
1477 	default:
1478 		ccbh->status = CAM_REQ_CMP_ERR;
1479 		break;
1480 	}
1481 
1482 	xpt_done(ccb);
1483 	vtscsi_enqueue_request(sc, req);
1484 }
1485 
1486 static int
1487 vtscsi_execute_abort_task_cmd(struct vtscsi_softc *sc,
1488     struct vtscsi_request *req)
1489 {
1490 	struct sglist *sg;
1491 	struct ccb_abort *cab;
1492 	struct ccb_hdr *ccbh;
1493 	struct ccb_hdr *abort_ccbh;
1494 	struct vtscsi_request *abort_req;
1495 	struct virtio_scsi_ctrl_tmf_req *tmf_req;
1496 	struct virtio_scsi_ctrl_tmf_resp *tmf_resp;
1497 	int error;
1498 
1499 	sg = sc->vtscsi_sglist;
1500 	cab = &req->vsr_ccb->cab;
1501 	ccbh = &cab->ccb_h;
1502 	tmf_req = &req->vsr_tmf_req;
1503 	tmf_resp = &req->vsr_tmf_resp;
1504 
1505 	/* CCB header and request that's to be aborted. */
1506 	abort_ccbh = &cab->abort_ccb->ccb_h;
1507 	abort_req = abort_ccbh->ccbh_vtscsi_req;
1508 
1509 	if (abort_ccbh->func_code != XPT_SCSI_IO || abort_req == NULL) {
1510 		error = EINVAL;
1511 		goto fail;
1512 	}
1513 
1514 	/* Only attempt to abort requests that could be in-flight. */
1515 	if (abort_req->vsr_state != VTSCSI_REQ_STATE_INUSE) {
1516 		error = EALREADY;
1517 		goto fail;
1518 	}
1519 
1520 	abort_req->vsr_state = VTSCSI_REQ_STATE_ABORTED;
1521 	if (abort_req->vsr_flags & VTSCSI_REQ_FLAG_TIMEOUT_SET)
1522 		callout_stop(&abort_req->vsr_callout);
1523 
1524 	vtscsi_init_ctrl_tmf_req(sc, ccbh, VIRTIO_SCSI_T_TMF_ABORT_TASK,
1525 	    (uintptr_t) abort_ccbh, tmf_req);
1526 
1527 	sglist_reset(sg);
1528 	sglist_append(sg, tmf_req, sizeof(struct virtio_scsi_ctrl_tmf_req));
1529 	sglist_append(sg, tmf_resp, sizeof(struct virtio_scsi_ctrl_tmf_resp));
1530 
1531 	req->vsr_complete = vtscsi_complete_abort_task_cmd;
1532 	tmf_resp->response = -1;
1533 
1534 	error = vtscsi_execute_ctrl_req(sc, req, sg, 1, 1,
1535 	    VTSCSI_EXECUTE_ASYNC);
1536 
1537 fail:
1538 	vtscsi_dprintf(sc, VTSCSI_TRACE, "error=%d req=%p abort_ccb=%p "
1539 	    "abort_req=%p\n", error, req, abort_ccbh, abort_req);
1540 
1541 	return (error);
1542 }
1543 
1544 static void
1545 vtscsi_complete_reset_dev_cmd(struct vtscsi_softc *sc,
1546     struct vtscsi_request *req)
1547 {
1548 	union ccb *ccb;
1549 	struct ccb_hdr *ccbh;
1550 	struct virtio_scsi_ctrl_tmf_resp *tmf_resp;
1551 
1552 	ccb = req->vsr_ccb;
1553 	ccbh = &ccb->ccb_h;
1554 	tmf_resp = &req->vsr_tmf_resp;
1555 
1556 	vtscsi_dprintf(sc, VTSCSI_TRACE, "req=%p ccb=%p response=%d\n",
1557 	    req, ccb, tmf_resp->response);
1558 
1559 	if (tmf_resp->response == VIRTIO_SCSI_S_FUNCTION_COMPLETE) {
1560 		ccbh->status = CAM_REQ_CMP;
1561 		vtscsi_announce(sc, AC_SENT_BDR, ccbh->target_id,
1562 		    ccbh->target_lun);
1563 	} else
1564 		ccbh->status = CAM_REQ_CMP_ERR;
1565 
1566 	xpt_done(ccb);
1567 	vtscsi_enqueue_request(sc, req);
1568 }
1569 
1570 static int
1571 vtscsi_execute_reset_dev_cmd(struct vtscsi_softc *sc,
1572     struct vtscsi_request *req)
1573 {
1574 	struct sglist *sg;
1575 	struct ccb_resetdev *crd;
1576 	struct ccb_hdr *ccbh;
1577 	struct virtio_scsi_ctrl_tmf_req *tmf_req;
1578 	struct virtio_scsi_ctrl_tmf_resp *tmf_resp;
1579 	uint32_t subtype;
1580 	int error;
1581 
1582 	sg = sc->vtscsi_sglist;
1583 	crd = &req->vsr_ccb->crd;
1584 	ccbh = &crd->ccb_h;
1585 	tmf_req = &req->vsr_tmf_req;
1586 	tmf_resp = &req->vsr_tmf_resp;
1587 
1588 	if (ccbh->target_lun == CAM_LUN_WILDCARD)
1589 		subtype = VIRTIO_SCSI_T_TMF_I_T_NEXUS_RESET;
1590 	else
1591 		subtype = VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET;
1592 
1593 	vtscsi_init_ctrl_tmf_req(sc, ccbh, subtype, 0, tmf_req);
1594 
1595 	sglist_reset(sg);
1596 	sglist_append(sg, tmf_req, sizeof(struct virtio_scsi_ctrl_tmf_req));
1597 	sglist_append(sg, tmf_resp, sizeof(struct virtio_scsi_ctrl_tmf_resp));
1598 
1599 	req->vsr_complete = vtscsi_complete_reset_dev_cmd;
1600 	tmf_resp->response = -1;
1601 
1602 	error = vtscsi_execute_ctrl_req(sc, req, sg, 1, 1,
1603 	    VTSCSI_EXECUTE_ASYNC);
1604 
1605 	vtscsi_dprintf(sc, VTSCSI_TRACE, "error=%d req=%p ccb=%p\n",
1606 	    error, req, ccbh);
1607 
1608 	return (error);
1609 }
1610 
1611 static void
1612 vtscsi_get_request_lun(uint8_t lun[], target_id_t *target_id, lun_id_t *lun_id)
1613 {
1614 
1615 	*target_id = lun[1];
1616 	*lun_id = (lun[2] << 8) | lun[3];
1617 }
1618 
1619 static void
1620 vtscsi_set_request_lun(struct ccb_hdr *ccbh, uint8_t lun[])
1621 {
1622 
1623 	lun[0] = 1;
1624 	lun[1] = ccbh->target_id;
1625 	lun[2] = 0x40 | ((ccbh->target_lun >> 8) & 0x3F);
1626 	lun[3] = ccbh->target_lun & 0xFF;
1627 }
1628 
1629 static void
1630 vtscsi_init_scsi_cmd_req(struct vtscsi_softc *sc, struct ccb_scsiio *csio,
1631     struct virtio_scsi_cmd_req *cmd_req)
1632 {
1633 	uint8_t attr;
1634 
1635 	switch (csio->tag_action) {
1636 	case MSG_HEAD_OF_Q_TAG:
1637 		attr = VIRTIO_SCSI_S_HEAD;
1638 		break;
1639 	case MSG_ORDERED_Q_TAG:
1640 		attr = VIRTIO_SCSI_S_ORDERED;
1641 		break;
1642 	case MSG_ACA_TASK:
1643 		attr = VIRTIO_SCSI_S_ACA;
1644 		break;
1645 	default: /* MSG_SIMPLE_Q_TAG */
1646 		attr = VIRTIO_SCSI_S_SIMPLE;
1647 		break;
1648 	}
1649 
1650 	vtscsi_set_request_lun(&csio->ccb_h, cmd_req->lun);
1651 	cmd_req->tag = vtscsi_gtoh64(sc, (uintptr_t) csio);
1652 	cmd_req->task_attr = attr;
1653 
1654 	memcpy(cmd_req->cdb,
1655 	    csio->ccb_h.flags & CAM_CDB_POINTER ?
1656 	        csio->cdb_io.cdb_ptr : csio->cdb_io.cdb_bytes,
1657 	    csio->cdb_len);
1658 }
1659 
1660 static void
1661 vtscsi_init_ctrl_tmf_req(struct vtscsi_softc *sc, struct ccb_hdr *ccbh,
1662     uint32_t subtype, uintptr_t tag, struct virtio_scsi_ctrl_tmf_req *tmf_req)
1663 {
1664 
1665 	vtscsi_set_request_lun(ccbh, tmf_req->lun);
1666 
1667 	tmf_req->type = vtscsi_gtoh32(sc, VIRTIO_SCSI_T_TMF);
1668 	tmf_req->subtype = vtscsi_gtoh32(sc, subtype);
1669 	tmf_req->tag = vtscsi_gtoh64(sc, tag);
1670 }
1671 
1672 static void
1673 vtscsi_freeze_simq(struct vtscsi_softc *sc, int reason)
1674 {
1675 	int frozen;
1676 
1677 	frozen = sc->vtscsi_frozen;
1678 
1679 	if (reason & VTSCSI_REQUEST &&
1680 	    (sc->vtscsi_frozen & VTSCSI_FROZEN_NO_REQUESTS) == 0)
1681 		sc->vtscsi_frozen |= VTSCSI_FROZEN_NO_REQUESTS;
1682 
1683 	if (reason & VTSCSI_REQUEST_VQ &&
1684 	    (sc->vtscsi_frozen & VTSCSI_FROZEN_REQUEST_VQ_FULL) == 0)
1685 		sc->vtscsi_frozen |= VTSCSI_FROZEN_REQUEST_VQ_FULL;
1686 
1687 	/* Freeze the SIMQ if transitioned to frozen. */
1688 	if (frozen == 0 && sc->vtscsi_frozen != 0) {
1689 		vtscsi_dprintf(sc, VTSCSI_INFO, "SIMQ frozen\n");
1690 		xpt_freeze_simq(sc->vtscsi_sim, 1);
1691 	}
1692 }
1693 
1694 static int
1695 vtscsi_thaw_simq(struct vtscsi_softc *sc, int reason)
1696 {
1697 	int thawed;
1698 
1699 	if (sc->vtscsi_frozen == 0 || reason == 0)
1700 		return (0);
1701 
1702 	if (reason & VTSCSI_REQUEST &&
1703 	    sc->vtscsi_frozen & VTSCSI_FROZEN_NO_REQUESTS)
1704 		sc->vtscsi_frozen &= ~VTSCSI_FROZEN_NO_REQUESTS;
1705 
1706 	if (reason & VTSCSI_REQUEST_VQ &&
1707 	    sc->vtscsi_frozen & VTSCSI_FROZEN_REQUEST_VQ_FULL)
1708 		sc->vtscsi_frozen &= ~VTSCSI_FROZEN_REQUEST_VQ_FULL;
1709 
1710 	thawed = sc->vtscsi_frozen == 0;
1711 	if (thawed != 0)
1712 		vtscsi_dprintf(sc, VTSCSI_INFO, "SIMQ thawed\n");
1713 
1714 	return (thawed);
1715 }
1716 
1717 static void
1718 vtscsi_announce(struct vtscsi_softc *sc, uint32_t ac_code,
1719     target_id_t target_id, lun_id_t lun_id)
1720 {
1721 	struct cam_path *path;
1722 
1723 	/* Use the wildcard path from our softc for bus announcements. */
1724 	if (target_id == CAM_TARGET_WILDCARD && lun_id == CAM_LUN_WILDCARD) {
1725 		xpt_async(ac_code, sc->vtscsi_path, NULL);
1726 		return;
1727 	}
1728 
1729 	if (xpt_create_path(&path, NULL, cam_sim_path(sc->vtscsi_sim),
1730 	    target_id, lun_id) != CAM_REQ_CMP) {
1731 		vtscsi_dprintf(sc, VTSCSI_ERROR, "cannot create path\n");
1732 		return;
1733 	}
1734 
1735 	xpt_async(ac_code, path, NULL);
1736 	xpt_free_path(path);
1737 }
1738 
1739 static void
1740 vtscsi_execute_rescan(struct vtscsi_softc *sc, target_id_t target_id,
1741     lun_id_t lun_id)
1742 {
1743 	union ccb *ccb;
1744 	cam_status status;
1745 
1746 	ccb = xpt_alloc_ccb_nowait();
1747 	if (ccb == NULL) {
1748 		vtscsi_dprintf(sc, VTSCSI_ERROR, "cannot allocate CCB\n");
1749 		return;
1750 	}
1751 
1752 	status = xpt_create_path(&ccb->ccb_h.path, NULL,
1753 	    cam_sim_path(sc->vtscsi_sim), target_id, lun_id);
1754 	if (status != CAM_REQ_CMP) {
1755 		xpt_free_ccb(ccb);
1756 		return;
1757 	}
1758 
1759 	xpt_rescan(ccb);
1760 }
1761 
1762 static void
1763 vtscsi_execute_rescan_bus(struct vtscsi_softc *sc)
1764 {
1765 
1766 	vtscsi_execute_rescan(sc, CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
1767 }
1768 
1769 static void
1770 vtscsi_transport_reset_event(struct vtscsi_softc *sc,
1771     struct virtio_scsi_event *event)
1772 {
1773 	target_id_t target_id;
1774 	lun_id_t lun_id;
1775 
1776 	vtscsi_get_request_lun(event->lun, &target_id, &lun_id);
1777 
1778 	switch (event->reason) {
1779 	case VIRTIO_SCSI_EVT_RESET_RESCAN:
1780 	case VIRTIO_SCSI_EVT_RESET_REMOVED:
1781 		vtscsi_execute_rescan(sc, target_id, lun_id);
1782 		break;
1783 	default:
1784 		device_printf(sc->vtscsi_dev,
1785 		    "unhandled transport event reason: %d\n", event->reason);
1786 		break;
1787 	}
1788 }
1789 
1790 static void
1791 vtscsi_handle_event(struct vtscsi_softc *sc, struct virtio_scsi_event *event)
1792 {
1793 	int error __diagused;
1794 
1795 	if ((event->event & VIRTIO_SCSI_T_EVENTS_MISSED) == 0) {
1796 		switch (event->event) {
1797 		case VIRTIO_SCSI_T_TRANSPORT_RESET:
1798 			vtscsi_transport_reset_event(sc, event);
1799 			break;
1800 		default:
1801 			device_printf(sc->vtscsi_dev,
1802 			    "unhandled event: %d\n", event->event);
1803 			break;
1804 		}
1805 	} else
1806 		vtscsi_execute_rescan_bus(sc);
1807 
1808 	/*
1809 	 * This should always be successful since the buffer
1810 	 * was just dequeued.
1811 	 */
1812 	error = vtscsi_enqueue_event_buf(sc, event);
1813 	KASSERT(error == 0,
1814 	    ("cannot requeue event buffer: %d", error));
1815 }
1816 
1817 static int
1818 vtscsi_enqueue_event_buf(struct vtscsi_softc *sc,
1819     struct virtio_scsi_event *event)
1820 {
1821 	struct sglist *sg;
1822 	struct virtqueue *vq;
1823 	int size, error;
1824 
1825 	sg = sc->vtscsi_sglist;
1826 	vq = sc->vtscsi_event_vq;
1827 	size = sc->vtscsi_event_buf_size;
1828 
1829 	bzero(event, size);
1830 
1831 	sglist_reset(sg);
1832 	error = sglist_append(sg, event, size);
1833 	if (error)
1834 		return (error);
1835 
1836 	error = virtqueue_enqueue(vq, event, sg, 0, sg->sg_nseg);
1837 	if (error)
1838 		return (error);
1839 
1840 	virtqueue_notify(vq);
1841 
1842 	return (0);
1843 }
1844 
1845 static int
1846 vtscsi_init_event_vq(struct vtscsi_softc *sc)
1847 {
1848 	struct virtio_scsi_event *event;
1849 	int i, size, error;
1850 
1851 	/*
1852 	 * The first release of QEMU with VirtIO SCSI support would crash
1853 	 * when attempting to notify the event virtqueue. This was fixed
1854 	 * when hotplug support was added.
1855 	 */
1856 	if (sc->vtscsi_flags & VTSCSI_FLAG_HOTPLUG)
1857 		size = sc->vtscsi_event_buf_size;
1858 	else
1859 		size = 0;
1860 
1861 	if (size < sizeof(struct virtio_scsi_event))
1862 		return (0);
1863 
1864 	for (i = 0; i < VTSCSI_NUM_EVENT_BUFS; i++) {
1865 		event = &sc->vtscsi_event_bufs[i];
1866 
1867 		error = vtscsi_enqueue_event_buf(sc, event);
1868 		if (error)
1869 			break;
1870 	}
1871 
1872 	/*
1873 	 * Even just one buffer is enough. Missed events are
1874 	 * denoted with the VIRTIO_SCSI_T_EVENTS_MISSED flag.
1875 	 */
1876 	if (i > 0)
1877 		error = 0;
1878 
1879 	return (error);
1880 }
1881 
1882 static void
1883 vtscsi_reinit_event_vq(struct vtscsi_softc *sc)
1884 {
1885 	struct virtio_scsi_event *event;
1886 	int i, error;
1887 
1888 	if ((sc->vtscsi_flags & VTSCSI_FLAG_HOTPLUG) == 0 ||
1889 	    sc->vtscsi_event_buf_size < sizeof(struct virtio_scsi_event))
1890 		return;
1891 
1892 	for (i = 0; i < VTSCSI_NUM_EVENT_BUFS; i++) {
1893 		event = &sc->vtscsi_event_bufs[i];
1894 
1895 		error = vtscsi_enqueue_event_buf(sc, event);
1896 		if (error)
1897 			break;
1898 	}
1899 
1900 	KASSERT(i > 0, ("cannot reinit event vq: %d", error));
1901 }
1902 
1903 static void
1904 vtscsi_drain_event_vq(struct vtscsi_softc *sc)
1905 {
1906 	struct virtqueue *vq;
1907 	int last;
1908 
1909 	vq = sc->vtscsi_event_vq;
1910 	last = 0;
1911 
1912 	while (virtqueue_drain(vq, &last) != NULL)
1913 		;
1914 
1915 	KASSERT(virtqueue_empty(vq), ("eventvq not empty"));
1916 }
1917 
1918 static void
1919 vtscsi_complete_vqs_locked(struct vtscsi_softc *sc)
1920 {
1921 
1922 	VTSCSI_LOCK_OWNED(sc);
1923 
1924 	if (sc->vtscsi_request_vq != NULL)
1925 		vtscsi_complete_vq(sc, sc->vtscsi_request_vq);
1926 	if (sc->vtscsi_control_vq != NULL)
1927 		vtscsi_complete_vq(sc, sc->vtscsi_control_vq);
1928 }
1929 
1930 static void
1931 vtscsi_complete_vqs(struct vtscsi_softc *sc)
1932 {
1933 
1934 	VTSCSI_LOCK(sc);
1935 	vtscsi_complete_vqs_locked(sc);
1936 	VTSCSI_UNLOCK(sc);
1937 }
1938 
1939 static void
1940 vtscsi_cancel_request(struct vtscsi_softc *sc, struct vtscsi_request *req)
1941 {
1942 	union ccb *ccb;
1943 	int detach;
1944 
1945 	ccb = req->vsr_ccb;
1946 
1947 	vtscsi_dprintf(sc, VTSCSI_TRACE, "req=%p ccb=%p\n", req, ccb);
1948 
1949 	/*
1950 	 * The callout must be drained when detaching since the request is
1951 	 * about to be freed. The VTSCSI_MTX must not be held for this in
1952 	 * case the callout is pending because there is a deadlock potential.
1953 	 * Otherwise, the virtqueue is being drained because of a bus reset
1954 	 * so we only need to attempt to stop the callouts.
1955 	 */
1956 	detach = (sc->vtscsi_flags & VTSCSI_FLAG_DETACH) != 0;
1957 	if (detach != 0)
1958 		VTSCSI_LOCK_NOTOWNED(sc);
1959 	else
1960 		VTSCSI_LOCK_OWNED(sc);
1961 
1962 	if (req->vsr_flags & VTSCSI_REQ_FLAG_TIMEOUT_SET) {
1963 		if (detach != 0)
1964 			callout_drain(&req->vsr_callout);
1965 		else
1966 			callout_stop(&req->vsr_callout);
1967 	}
1968 
1969 	if (ccb != NULL) {
1970 		if (detach != 0) {
1971 			VTSCSI_LOCK(sc);
1972 			ccb->ccb_h.status = CAM_NO_HBA;
1973 		} else
1974 			ccb->ccb_h.status = CAM_REQUEUE_REQ;
1975 		xpt_done(ccb);
1976 		if (detach != 0)
1977 			VTSCSI_UNLOCK(sc);
1978 	}
1979 
1980 	vtscsi_enqueue_request(sc, req);
1981 }
1982 
1983 static void
1984 vtscsi_drain_vq(struct vtscsi_softc *sc, struct virtqueue *vq)
1985 {
1986 	struct vtscsi_request *req;
1987 	int last;
1988 
1989 	last = 0;
1990 
1991 	vtscsi_dprintf(sc, VTSCSI_TRACE, "vq=%p\n", vq);
1992 
1993 	while ((req = virtqueue_drain(vq, &last)) != NULL)
1994 		vtscsi_cancel_request(sc, req);
1995 
1996 	KASSERT(virtqueue_empty(vq), ("virtqueue not empty"));
1997 }
1998 
1999 static void
2000 vtscsi_drain_vqs(struct vtscsi_softc *sc)
2001 {
2002 
2003 	if (sc->vtscsi_control_vq != NULL)
2004 		vtscsi_drain_vq(sc, sc->vtscsi_control_vq);
2005 	if (sc->vtscsi_request_vq != NULL)
2006 		vtscsi_drain_vq(sc, sc->vtscsi_request_vq);
2007 	if (sc->vtscsi_event_vq != NULL)
2008 		vtscsi_drain_event_vq(sc);
2009 }
2010 
2011 static void
2012 vtscsi_stop(struct vtscsi_softc *sc)
2013 {
2014 
2015 	vtscsi_disable_vqs_intr(sc);
2016 	virtio_stop(sc->vtscsi_dev);
2017 }
2018 
2019 static int
2020 vtscsi_reset_bus(struct vtscsi_softc *sc)
2021 {
2022 	int error;
2023 
2024 	VTSCSI_LOCK_OWNED(sc);
2025 
2026 	if (vtscsi_bus_reset_disable != 0) {
2027 		device_printf(sc->vtscsi_dev, "bus reset disabled\n");
2028 		return (0);
2029 	}
2030 
2031 	sc->vtscsi_flags |= VTSCSI_FLAG_RESET;
2032 
2033 	/*
2034 	 * vtscsi_stop() will cause the in-flight requests to be canceled.
2035 	 * Those requests are then completed here so CAM will retry them
2036 	 * after the reset is complete.
2037 	 */
2038 	vtscsi_stop(sc);
2039 	vtscsi_complete_vqs_locked(sc);
2040 
2041 	/* Rid the virtqueues of any remaining requests. */
2042 	vtscsi_drain_vqs(sc);
2043 
2044 	/*
2045 	 * Any resource shortage that froze the SIMQ cannot persist across
2046 	 * a bus reset so ensure it gets thawed here.
2047 	 */
2048 	if (vtscsi_thaw_simq(sc, VTSCSI_REQUEST | VTSCSI_REQUEST_VQ) != 0)
2049 		xpt_release_simq(sc->vtscsi_sim, 0);
2050 
2051 	error = vtscsi_reinit(sc);
2052 	if (error) {
2053 		device_printf(sc->vtscsi_dev,
2054 		    "reinitialization failed, stopping device...\n");
2055 		vtscsi_stop(sc);
2056 	} else
2057 		vtscsi_announce(sc, AC_BUS_RESET, CAM_TARGET_WILDCARD,
2058 		    CAM_LUN_WILDCARD);
2059 
2060 	sc->vtscsi_flags &= ~VTSCSI_FLAG_RESET;
2061 
2062 	return (error);
2063 }
2064 
2065 static void
2066 vtscsi_init_request(struct vtscsi_softc *sc, struct vtscsi_request *req)
2067 {
2068 
2069 #ifdef INVARIANTS
2070 	int req_nsegs, resp_nsegs;
2071 
2072 	req_nsegs = sglist_count(&req->vsr_ureq, sizeof(req->vsr_ureq));
2073 	resp_nsegs = sglist_count(&req->vsr_uresp, sizeof(req->vsr_uresp));
2074 
2075 	KASSERT(req_nsegs == 1, ("request crossed page boundary"));
2076 	KASSERT(resp_nsegs == 1, ("response crossed page boundary"));
2077 #endif
2078 
2079 	req->vsr_softc = sc;
2080 	callout_init_mtx(&req->vsr_callout, VTSCSI_MTX(sc), 0);
2081 }
2082 
2083 static int
2084 vtscsi_alloc_requests(struct vtscsi_softc *sc)
2085 {
2086 	struct vtscsi_request *req;
2087 	int i, nreqs;
2088 
2089 	/*
2090 	 * Commands destined for either the request or control queues come
2091 	 * from the same SIM queue. Use the size of the request virtqueue
2092 	 * as it (should) be much more frequently used. Some additional
2093 	 * requests are allocated for internal (TMF) use.
2094 	 */
2095 	nreqs = virtqueue_size(sc->vtscsi_request_vq);
2096 	if ((sc->vtscsi_flags & VTSCSI_FLAG_INDIRECT) == 0)
2097 		nreqs /= VTSCSI_MIN_SEGMENTS;
2098 	nreqs += VTSCSI_RESERVED_REQUESTS;
2099 
2100 	for (i = 0; i < nreqs; i++) {
2101 		req = malloc(sizeof(struct vtscsi_request), M_DEVBUF,
2102 		    M_NOWAIT);
2103 		if (req == NULL)
2104 			return (ENOMEM);
2105 
2106 		vtscsi_init_request(sc, req);
2107 
2108 		sc->vtscsi_nrequests++;
2109 		vtscsi_enqueue_request(sc, req);
2110 	}
2111 
2112 	return (0);
2113 }
2114 
2115 static void
2116 vtscsi_free_requests(struct vtscsi_softc *sc)
2117 {
2118 	struct vtscsi_request *req;
2119 
2120 	while ((req = vtscsi_dequeue_request(sc)) != NULL) {
2121 		KASSERT(callout_active(&req->vsr_callout) == 0,
2122 		    ("request callout still active"));
2123 
2124 		sc->vtscsi_nrequests--;
2125 		free(req, M_DEVBUF);
2126 	}
2127 
2128 	KASSERT(sc->vtscsi_nrequests == 0, ("leaked requests: %d",
2129 	    sc->vtscsi_nrequests));
2130 }
2131 
2132 static void
2133 vtscsi_enqueue_request(struct vtscsi_softc *sc, struct vtscsi_request *req)
2134 {
2135 
2136 	KASSERT(req->vsr_softc == sc,
2137 	    ("non-matching request vsr_softc %p/%p", req->vsr_softc, sc));
2138 
2139 	vtscsi_dprintf(sc, VTSCSI_TRACE, "req=%p\n", req);
2140 
2141 	/* A request is available so the SIMQ could be released. */
2142 	if (vtscsi_thaw_simq(sc, VTSCSI_REQUEST) != 0)
2143 		xpt_release_simq(sc->vtscsi_sim, 1);
2144 
2145 	req->vsr_ccb = NULL;
2146 	req->vsr_complete = NULL;
2147 	req->vsr_ptr0 = NULL;
2148 	req->vsr_state = VTSCSI_REQ_STATE_FREE;
2149 	req->vsr_flags = 0;
2150 
2151 	bzero(&req->vsr_ureq, sizeof(req->vsr_ureq));
2152 	bzero(&req->vsr_uresp, sizeof(req->vsr_uresp));
2153 
2154 	/*
2155 	 * We insert at the tail of the queue in order to make it
2156 	 * very unlikely a request will be reused if we race with
2157 	 * stopping its callout handler.
2158 	 */
2159 	TAILQ_INSERT_TAIL(&sc->vtscsi_req_free, req, vsr_link);
2160 }
2161 
2162 static struct vtscsi_request *
2163 vtscsi_dequeue_request(struct vtscsi_softc *sc)
2164 {
2165 	struct vtscsi_request *req;
2166 
2167 	req = TAILQ_FIRST(&sc->vtscsi_req_free);
2168 	if (req != NULL) {
2169 		req->vsr_state = VTSCSI_REQ_STATE_INUSE;
2170 		TAILQ_REMOVE(&sc->vtscsi_req_free, req, vsr_link);
2171 	} else
2172 		sc->vtscsi_stats.dequeue_no_requests++;
2173 
2174 	vtscsi_dprintf(sc, VTSCSI_TRACE, "req=%p\n", req);
2175 
2176 	return (req);
2177 }
2178 
2179 static void
2180 vtscsi_complete_request(struct vtscsi_request *req)
2181 {
2182 
2183 	if (req->vsr_flags & VTSCSI_REQ_FLAG_POLLED)
2184 		req->vsr_flags |= VTSCSI_REQ_FLAG_COMPLETE;
2185 
2186 	if (req->vsr_complete != NULL)
2187 		req->vsr_complete(req->vsr_softc, req);
2188 }
2189 
2190 static void
2191 vtscsi_complete_vq(struct vtscsi_softc *sc, struct virtqueue *vq)
2192 {
2193 	struct vtscsi_request *req;
2194 
2195 	VTSCSI_LOCK_OWNED(sc);
2196 
2197 	while ((req = virtqueue_dequeue(vq, NULL)) != NULL)
2198 		vtscsi_complete_request(req);
2199 }
2200 
2201 static void
2202 vtscsi_control_vq_intr(void *xsc)
2203 {
2204 	struct vtscsi_softc *sc;
2205 	struct virtqueue *vq;
2206 
2207 	sc = xsc;
2208 	vq = sc->vtscsi_control_vq;
2209 
2210 again:
2211 	VTSCSI_LOCK(sc);
2212 
2213 	vtscsi_complete_vq(sc, sc->vtscsi_control_vq);
2214 
2215 	if (virtqueue_enable_intr(vq) != 0) {
2216 		virtqueue_disable_intr(vq);
2217 		VTSCSI_UNLOCK(sc);
2218 		goto again;
2219 	}
2220 
2221 	VTSCSI_UNLOCK(sc);
2222 }
2223 
2224 static void
2225 vtscsi_event_vq_intr(void *xsc)
2226 {
2227 	struct vtscsi_softc *sc;
2228 	struct virtqueue *vq;
2229 	struct virtio_scsi_event *event;
2230 
2231 	sc = xsc;
2232 	vq = sc->vtscsi_event_vq;
2233 
2234 again:
2235 	VTSCSI_LOCK(sc);
2236 
2237 	while ((event = virtqueue_dequeue(vq, NULL)) != NULL)
2238 		vtscsi_handle_event(sc, event);
2239 
2240 	if (virtqueue_enable_intr(vq) != 0) {
2241 		virtqueue_disable_intr(vq);
2242 		VTSCSI_UNLOCK(sc);
2243 		goto again;
2244 	}
2245 
2246 	VTSCSI_UNLOCK(sc);
2247 }
2248 
2249 static void
2250 vtscsi_request_vq_intr(void *xsc)
2251 {
2252 	struct vtscsi_softc *sc;
2253 	struct virtqueue *vq;
2254 
2255 	sc = xsc;
2256 	vq = sc->vtscsi_request_vq;
2257 
2258 again:
2259 	VTSCSI_LOCK(sc);
2260 
2261 	vtscsi_complete_vq(sc, sc->vtscsi_request_vq);
2262 
2263 	if (virtqueue_enable_intr(vq) != 0) {
2264 		virtqueue_disable_intr(vq);
2265 		VTSCSI_UNLOCK(sc);
2266 		goto again;
2267 	}
2268 
2269 	VTSCSI_UNLOCK(sc);
2270 }
2271 
2272 static void
2273 vtscsi_disable_vqs_intr(struct vtscsi_softc *sc)
2274 {
2275 
2276 	virtqueue_disable_intr(sc->vtscsi_control_vq);
2277 	virtqueue_disable_intr(sc->vtscsi_event_vq);
2278 	virtqueue_disable_intr(sc->vtscsi_request_vq);
2279 }
2280 
2281 static void
2282 vtscsi_enable_vqs_intr(struct vtscsi_softc *sc)
2283 {
2284 
2285 	virtqueue_enable_intr(sc->vtscsi_control_vq);
2286 	virtqueue_enable_intr(sc->vtscsi_event_vq);
2287 	virtqueue_enable_intr(sc->vtscsi_request_vq);
2288 }
2289 
2290 static void
2291 vtscsi_get_tunables(struct vtscsi_softc *sc)
2292 {
2293 	char tmpstr[64];
2294 
2295 	TUNABLE_INT_FETCH("hw.vtscsi.debug_level", &sc->vtscsi_debug);
2296 
2297 	snprintf(tmpstr, sizeof(tmpstr), "dev.vtscsi.%d.debug_level",
2298 	    device_get_unit(sc->vtscsi_dev));
2299 	TUNABLE_INT_FETCH(tmpstr, &sc->vtscsi_debug);
2300 }
2301 
2302 static void
2303 vtscsi_setup_sysctl(struct vtscsi_softc *sc)
2304 {
2305 	device_t dev;
2306 	struct vtscsi_statistics *stats;
2307         struct sysctl_ctx_list *ctx;
2308 	struct sysctl_oid *tree;
2309 	struct sysctl_oid_list *child;
2310 
2311 	dev = sc->vtscsi_dev;
2312 	stats = &sc->vtscsi_stats;
2313 	ctx = device_get_sysctl_ctx(dev);
2314 	tree = device_get_sysctl_tree(dev);
2315 	child = SYSCTL_CHILDREN(tree);
2316 
2317 	SYSCTL_ADD_INT(ctx, child, OID_AUTO, "debug_level",
2318 	    CTLFLAG_RW, &sc->vtscsi_debug, 0,
2319 	    "Debug level");
2320 
2321 	SYSCTL_ADD_ULONG(ctx, child, OID_AUTO, "scsi_cmd_timeouts",
2322 	    CTLFLAG_RD, &stats->scsi_cmd_timeouts,
2323 	    "SCSI command timeouts");
2324 	SYSCTL_ADD_ULONG(ctx, child, OID_AUTO, "dequeue_no_requests",
2325 	    CTLFLAG_RD, &stats->dequeue_no_requests,
2326 	    "No available requests to dequeue");
2327 }
2328 
2329 static void
2330 vtscsi_printf_req(struct vtscsi_request *req, const char *func,
2331     const char *fmt, ...)
2332 {
2333 	struct vtscsi_softc *sc;
2334 	union ccb *ccb;
2335 	struct sbuf sb;
2336 	va_list ap;
2337 	char str[192];
2338 
2339 	if (req == NULL)
2340 		return;
2341 
2342 	sc = req->vsr_softc;
2343 	ccb = req->vsr_ccb;
2344 
2345 	va_start(ap, fmt);
2346 	sbuf_new(&sb, str, sizeof(str), 0);
2347 
2348 	if (ccb == NULL) {
2349 		sbuf_printf(&sb, "(noperiph:%s%d:%u): ",
2350 		    cam_sim_name(sc->vtscsi_sim), cam_sim_unit(sc->vtscsi_sim),
2351 		    cam_sim_bus(sc->vtscsi_sim));
2352 	} else {
2353 		xpt_path_sbuf(ccb->ccb_h.path, &sb);
2354 		if (ccb->ccb_h.func_code == XPT_SCSI_IO) {
2355 			scsi_command_string(&ccb->csio, &sb);
2356 			sbuf_printf(&sb, "length %d ", ccb->csio.dxfer_len);
2357 		}
2358 	}
2359 
2360 	sbuf_vprintf(&sb, fmt, ap);
2361 	va_end(ap);
2362 
2363 	sbuf_finish(&sb);
2364 	printf("%s: %s: %s", device_get_nameunit(sc->vtscsi_dev), func,
2365 	    sbuf_data(&sb));
2366 }
2367