xref: /freebsd/sys/dev/virtio/scsi/virtio_scsi.c (revision 6be3386466ab79a84b48429ae66244f21526d3df)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/kernel.h>
37 #include <sys/kthread.h>
38 #include <sys/malloc.h>
39 #include <sys/module.h>
40 #include <sys/sglist.h>
41 #include <sys/sysctl.h>
42 #include <sys/lock.h>
43 #include <sys/mutex.h>
44 #include <sys/callout.h>
45 #include <sys/queue.h>
46 #include <sys/sbuf.h>
47 
48 #include <machine/stdarg.h>
49 
50 #include <machine/bus.h>
51 #include <machine/resource.h>
52 #include <sys/bus.h>
53 #include <sys/rman.h>
54 
55 #include <cam/cam.h>
56 #include <cam/cam_ccb.h>
57 #include <cam/cam_sim.h>
58 #include <cam/cam_periph.h>
59 #include <cam/cam_xpt_sim.h>
60 #include <cam/cam_debug.h>
61 #include <cam/scsi/scsi_all.h>
62 #include <cam/scsi/scsi_message.h>
63 
64 #include <dev/virtio/virtio.h>
65 #include <dev/virtio/virtqueue.h>
66 #include <dev/virtio/scsi/virtio_scsi.h>
67 #include <dev/virtio/scsi/virtio_scsivar.h>
68 
69 #include "virtio_if.h"
70 
71 static int	vtscsi_modevent(module_t, int, void *);
72 
73 static int	vtscsi_probe(device_t);
74 static int	vtscsi_attach(device_t);
75 static int	vtscsi_detach(device_t);
76 static int	vtscsi_suspend(device_t);
77 static int	vtscsi_resume(device_t);
78 
79 static int	vtscsi_negotiate_features(struct vtscsi_softc *);
80 static int	vtscsi_setup_features(struct vtscsi_softc *);
81 static void	vtscsi_read_config(struct vtscsi_softc *,
82 		    struct virtio_scsi_config *);
83 static int	vtscsi_maximum_segments(struct vtscsi_softc *, int);
84 static int	vtscsi_alloc_virtqueues(struct vtscsi_softc *);
85 static void	vtscsi_check_sizes(struct vtscsi_softc *);
86 static void	vtscsi_write_device_config(struct vtscsi_softc *);
87 static int	vtscsi_reinit(struct vtscsi_softc *);
88 
89 static int	vtscsi_alloc_cam(struct vtscsi_softc *);
90 static int	vtscsi_register_cam(struct vtscsi_softc *);
91 static void	vtscsi_free_cam(struct vtscsi_softc *);
92 static void	vtscsi_cam_async(void *, uint32_t, struct cam_path *, void *);
93 static int	vtscsi_register_async(struct vtscsi_softc *);
94 static void	vtscsi_deregister_async(struct vtscsi_softc *);
95 static void	vtscsi_cam_action(struct cam_sim *, union ccb *);
96 static void	vtscsi_cam_poll(struct cam_sim *);
97 
98 static void	vtscsi_cam_scsi_io(struct vtscsi_softc *, struct cam_sim *,
99 		    union ccb *);
100 static void	vtscsi_cam_get_tran_settings(struct vtscsi_softc *,
101 		    union ccb *);
102 static void	vtscsi_cam_reset_bus(struct vtscsi_softc *, union ccb *);
103 static void	vtscsi_cam_reset_dev(struct vtscsi_softc *, union ccb *);
104 static void	vtscsi_cam_abort(struct vtscsi_softc *, union ccb *);
105 static void	vtscsi_cam_path_inquiry(struct vtscsi_softc *,
106 		    struct cam_sim *, union ccb *);
107 
108 static int	vtscsi_sg_append_scsi_buf(struct vtscsi_softc *,
109 		    struct sglist *, struct ccb_scsiio *);
110 static int	vtscsi_fill_scsi_cmd_sglist(struct vtscsi_softc *,
111 		    struct vtscsi_request *, int *, int *);
112 static int	vtscsi_execute_scsi_cmd(struct vtscsi_softc *,
113 		    struct vtscsi_request *);
114 static int	vtscsi_start_scsi_cmd(struct vtscsi_softc *, union ccb *);
115 static void	vtscsi_complete_abort_timedout_scsi_cmd(struct vtscsi_softc *,
116 		    struct vtscsi_request *);
117 static int	vtscsi_abort_timedout_scsi_cmd(struct vtscsi_softc *,
118 		    struct vtscsi_request *);
119 static void	vtscsi_timedout_scsi_cmd(void *);
120 static cam_status vtscsi_scsi_cmd_cam_status(struct virtio_scsi_cmd_resp *);
121 static cam_status vtscsi_complete_scsi_cmd_response(struct vtscsi_softc *,
122 		    struct ccb_scsiio *, struct virtio_scsi_cmd_resp *);
123 static void	vtscsi_complete_scsi_cmd(struct vtscsi_softc *,
124 		    struct vtscsi_request *);
125 
126 static void	vtscsi_poll_ctrl_req(struct vtscsi_softc *,
127 		    struct vtscsi_request *);
128 static int	vtscsi_execute_ctrl_req(struct vtscsi_softc *,
129 		    struct vtscsi_request *, struct sglist *, int, int, int);
130 static void	vtscsi_complete_abort_task_cmd(struct vtscsi_softc *c,
131 		    struct vtscsi_request *);
132 static int	vtscsi_execute_abort_task_cmd(struct vtscsi_softc *,
133 		    struct vtscsi_request *);
134 static int	vtscsi_execute_reset_dev_cmd(struct vtscsi_softc *,
135 		    struct vtscsi_request *);
136 
137 static void	vtscsi_get_request_lun(uint8_t [], target_id_t *, lun_id_t *);
138 static void	vtscsi_set_request_lun(struct ccb_hdr *, uint8_t []);
139 static void	vtscsi_init_scsi_cmd_req(struct vtscsi_softc *,
140 		    struct ccb_scsiio *, struct virtio_scsi_cmd_req *);
141 static void	vtscsi_init_ctrl_tmf_req(struct vtscsi_softc *, struct ccb_hdr *,
142 		    uint32_t, uintptr_t, struct virtio_scsi_ctrl_tmf_req *);
143 
144 static void	vtscsi_freeze_simq(struct vtscsi_softc *, int);
145 static int	vtscsi_thaw_simq(struct vtscsi_softc *, int);
146 
147 static void	vtscsi_announce(struct vtscsi_softc *, uint32_t, target_id_t,
148 		    lun_id_t);
149 static void	vtscsi_execute_rescan(struct vtscsi_softc *, target_id_t,
150 		    lun_id_t);
151 static void	vtscsi_execute_rescan_bus(struct vtscsi_softc *);
152 
153 static void	vtscsi_handle_event(struct vtscsi_softc *,
154 		    struct virtio_scsi_event *);
155 static int	vtscsi_enqueue_event_buf(struct vtscsi_softc *,
156 		    struct virtio_scsi_event *);
157 static int	vtscsi_init_event_vq(struct vtscsi_softc *);
158 static void	vtscsi_reinit_event_vq(struct vtscsi_softc *);
159 static void	vtscsi_drain_event_vq(struct vtscsi_softc *);
160 
161 static void	vtscsi_complete_vqs_locked(struct vtscsi_softc *);
162 static void	vtscsi_complete_vqs(struct vtscsi_softc *);
163 static void	vtscsi_drain_vqs(struct vtscsi_softc *);
164 static void	vtscsi_cancel_request(struct vtscsi_softc *,
165 		    struct vtscsi_request *);
166 static void	vtscsi_drain_vq(struct vtscsi_softc *, struct virtqueue *);
167 static void	vtscsi_stop(struct vtscsi_softc *);
168 static int	vtscsi_reset_bus(struct vtscsi_softc *);
169 
170 static void	vtscsi_init_request(struct vtscsi_softc *,
171 		    struct vtscsi_request *);
172 static int	vtscsi_alloc_requests(struct vtscsi_softc *);
173 static void	vtscsi_free_requests(struct vtscsi_softc *);
174 static void	vtscsi_enqueue_request(struct vtscsi_softc *,
175 		    struct vtscsi_request *);
176 static struct vtscsi_request * vtscsi_dequeue_request(struct vtscsi_softc *);
177 
178 static void	vtscsi_complete_request(struct vtscsi_request *);
179 static void	vtscsi_complete_vq(struct vtscsi_softc *, struct virtqueue *);
180 
181 static void	vtscsi_control_vq_intr(void *);
182 static void	vtscsi_event_vq_intr(void *);
183 static void	vtscsi_request_vq_intr(void *);
184 static void	vtscsi_disable_vqs_intr(struct vtscsi_softc *);
185 static void	vtscsi_enable_vqs_intr(struct vtscsi_softc *);
186 
187 static void	vtscsi_get_tunables(struct vtscsi_softc *);
188 static void	vtscsi_setup_sysctl(struct vtscsi_softc *);
189 
190 static void	vtscsi_printf_req(struct vtscsi_request *, const char *,
191 		    const char *, ...);
192 
193 #define vtscsi_modern(_sc) (((_sc)->vtscsi_features & VIRTIO_F_VERSION_1) != 0)
194 #define vtscsi_htog16(_sc, _val)	virtio_htog16(vtscsi_modern(_sc), _val)
195 #define vtscsi_htog32(_sc, _val)	virtio_htog32(vtscsi_modern(_sc), _val)
196 #define vtscsi_htog64(_sc, _val)	virtio_htog64(vtscsi_modern(_sc), _val)
197 #define vtscsi_gtoh16(_sc, _val)	virtio_gtoh16(vtscsi_modern(_sc), _val)
198 #define vtscsi_gtoh32(_sc, _val)	virtio_gtoh32(vtscsi_modern(_sc), _val)
199 #define vtscsi_gtoh64(_sc, _val)	virtio_gtoh64(vtscsi_modern(_sc), _val)
200 
201 /* Global tunables. */
202 /*
203  * The current QEMU VirtIO SCSI implementation does not cancel in-flight
204  * IO during virtio_stop(). So in-flight requests still complete after the
205  * device reset. We would have to wait for all the in-flight IO to complete,
206  * which defeats the typical purpose of a bus reset. We could simulate the
207  * bus reset with either I_T_NEXUS_RESET of all the targets, or with
208  * LOGICAL_UNIT_RESET of all the LUNs (assuming there is space in the
209  * control virtqueue). But this isn't very useful if things really go off
210  * the rails, so default to disabled for now.
211  */
212 static int vtscsi_bus_reset_disable = 1;
213 TUNABLE_INT("hw.vtscsi.bus_reset_disable", &vtscsi_bus_reset_disable);
214 
215 static struct virtio_feature_desc vtscsi_feature_desc[] = {
216 	{ VIRTIO_SCSI_F_INOUT,		"InOut"		},
217 	{ VIRTIO_SCSI_F_HOTPLUG,	"Hotplug"	},
218 	{ VIRTIO_SCSI_F_CHANGE,		"ChangeEvent"	},
219 	{ VIRTIO_SCSI_F_T10_PI, 	"T10PI"		},
220 
221 	{ 0, NULL }
222 };
223 
224 static device_method_t vtscsi_methods[] = {
225 	/* Device methods. */
226 	DEVMETHOD(device_probe,		vtscsi_probe),
227 	DEVMETHOD(device_attach,	vtscsi_attach),
228 	DEVMETHOD(device_detach,	vtscsi_detach),
229 	DEVMETHOD(device_suspend,	vtscsi_suspend),
230 	DEVMETHOD(device_resume,	vtscsi_resume),
231 
232 	DEVMETHOD_END
233 };
234 
235 static driver_t vtscsi_driver = {
236 	"vtscsi",
237 	vtscsi_methods,
238 	sizeof(struct vtscsi_softc)
239 };
240 static devclass_t vtscsi_devclass;
241 
242 VIRTIO_DRIVER_MODULE(virtio_scsi, vtscsi_driver, vtscsi_devclass,
243     vtscsi_modevent, 0);
244 MODULE_VERSION(virtio_scsi, 1);
245 MODULE_DEPEND(virtio_scsi, virtio, 1, 1, 1);
246 MODULE_DEPEND(virtio_scsi, cam, 1, 1, 1);
247 
248 VIRTIO_SIMPLE_PNPINFO(virtio_scsi, VIRTIO_ID_SCSI, "VirtIO SCSI Adapter");
249 
250 static int
251 vtscsi_modevent(module_t mod, int type, void *unused)
252 {
253 	int error;
254 
255 	switch (type) {
256 	case MOD_LOAD:
257 	case MOD_QUIESCE:
258 	case MOD_UNLOAD:
259 	case MOD_SHUTDOWN:
260 		error = 0;
261 		break;
262 	default:
263 		error = EOPNOTSUPP;
264 		break;
265 	}
266 
267 	return (error);
268 }
269 
270 static int
271 vtscsi_probe(device_t dev)
272 {
273 	return (VIRTIO_SIMPLE_PROBE(dev, virtio_scsi));
274 }
275 
276 static int
277 vtscsi_attach(device_t dev)
278 {
279 	struct vtscsi_softc *sc;
280 	struct virtio_scsi_config scsicfg;
281 	int error;
282 
283 	sc = device_get_softc(dev);
284 	sc->vtscsi_dev = dev;
285 	virtio_set_feature_desc(dev, vtscsi_feature_desc);
286 
287 	VTSCSI_LOCK_INIT(sc, device_get_nameunit(dev));
288 	TAILQ_INIT(&sc->vtscsi_req_free);
289 
290 	vtscsi_get_tunables(sc);
291 	vtscsi_setup_sysctl(sc);
292 
293 	error = vtscsi_setup_features(sc);
294 	if (error) {
295 		device_printf(dev, "cannot setup features\n");
296 		goto fail;
297 	}
298 
299 	vtscsi_read_config(sc, &scsicfg);
300 
301 	sc->vtscsi_max_channel = scsicfg.max_channel;
302 	sc->vtscsi_max_target = scsicfg.max_target;
303 	sc->vtscsi_max_lun = scsicfg.max_lun;
304 	sc->vtscsi_event_buf_size = scsicfg.event_info_size;
305 
306 	vtscsi_write_device_config(sc);
307 
308 	sc->vtscsi_max_nsegs = vtscsi_maximum_segments(sc, scsicfg.seg_max);
309 	sc->vtscsi_sglist = sglist_alloc(sc->vtscsi_max_nsegs, M_NOWAIT);
310 	if (sc->vtscsi_sglist == NULL) {
311 		error = ENOMEM;
312 		device_printf(dev, "cannot allocate sglist\n");
313 		goto fail;
314 	}
315 
316 	error = vtscsi_alloc_virtqueues(sc);
317 	if (error) {
318 		device_printf(dev, "cannot allocate virtqueues\n");
319 		goto fail;
320 	}
321 
322 	vtscsi_check_sizes(sc);
323 
324 	error = vtscsi_init_event_vq(sc);
325 	if (error) {
326 		device_printf(dev, "cannot populate the eventvq\n");
327 		goto fail;
328 	}
329 
330 	error = vtscsi_alloc_requests(sc);
331 	if (error) {
332 		device_printf(dev, "cannot allocate requests\n");
333 		goto fail;
334 	}
335 
336 	error = vtscsi_alloc_cam(sc);
337 	if (error) {
338 		device_printf(dev, "cannot allocate CAM structures\n");
339 		goto fail;
340 	}
341 
342 	error = virtio_setup_intr(dev, INTR_TYPE_CAM);
343 	if (error) {
344 		device_printf(dev, "cannot setup virtqueue interrupts\n");
345 		goto fail;
346 	}
347 
348 	vtscsi_enable_vqs_intr(sc);
349 
350 	/*
351 	 * Register with CAM after interrupts are enabled so we will get
352 	 * notified of the probe responses.
353 	 */
354 	error = vtscsi_register_cam(sc);
355 	if (error) {
356 		device_printf(dev, "cannot register with CAM\n");
357 		goto fail;
358 	}
359 
360 fail:
361 	if (error)
362 		vtscsi_detach(dev);
363 
364 	return (error);
365 }
366 
367 static int
368 vtscsi_detach(device_t dev)
369 {
370 	struct vtscsi_softc *sc;
371 
372 	sc = device_get_softc(dev);
373 
374 	VTSCSI_LOCK(sc);
375 	sc->vtscsi_flags |= VTSCSI_FLAG_DETACH;
376 	if (device_is_attached(dev))
377 		vtscsi_stop(sc);
378 	VTSCSI_UNLOCK(sc);
379 
380 	vtscsi_complete_vqs(sc);
381 	vtscsi_drain_vqs(sc);
382 
383 	vtscsi_free_cam(sc);
384 	vtscsi_free_requests(sc);
385 
386 	if (sc->vtscsi_sglist != NULL) {
387 		sglist_free(sc->vtscsi_sglist);
388 		sc->vtscsi_sglist = NULL;
389 	}
390 
391 	VTSCSI_LOCK_DESTROY(sc);
392 
393 	return (0);
394 }
395 
396 static int
397 vtscsi_suspend(device_t dev)
398 {
399 
400 	return (0);
401 }
402 
403 static int
404 vtscsi_resume(device_t dev)
405 {
406 
407 	return (0);
408 }
409 
410 static int
411 vtscsi_negotiate_features(struct vtscsi_softc *sc)
412 {
413 	device_t dev;
414 	uint64_t features;
415 
416 	dev = sc->vtscsi_dev;
417 	features = VTSCSI_FEATURES;
418 
419 	sc->vtscsi_features = virtio_negotiate_features(dev, features);
420 	return (virtio_finalize_features(dev));
421 }
422 
423 static int
424 vtscsi_setup_features(struct vtscsi_softc *sc)
425 {
426 	device_t dev;
427 	int error;
428 
429 	dev = sc->vtscsi_dev;
430 
431 	error = vtscsi_negotiate_features(sc);
432 	if (error)
433 		return (error);
434 
435 	if (virtio_with_feature(dev, VIRTIO_RING_F_INDIRECT_DESC))
436 		sc->vtscsi_flags |= VTSCSI_FLAG_INDIRECT;
437 	if (virtio_with_feature(dev, VIRTIO_SCSI_F_INOUT))
438 		sc->vtscsi_flags |= VTSCSI_FLAG_BIDIRECTIONAL;
439 	if (virtio_with_feature(dev, VIRTIO_SCSI_F_HOTPLUG))
440 		sc->vtscsi_flags |= VTSCSI_FLAG_HOTPLUG;
441 
442 	return (0);
443 }
444 
445 #define VTSCSI_GET_CONFIG(_dev, _field, _cfg)			\
446 	virtio_read_device_config(_dev,				\
447 	    offsetof(struct virtio_scsi_config, _field),	\
448 	    &(_cfg)->_field, sizeof((_cfg)->_field))		\
449 
450 static void
451 vtscsi_read_config(struct vtscsi_softc *sc,
452     struct virtio_scsi_config *scsicfg)
453 {
454 	device_t dev;
455 
456 	dev = sc->vtscsi_dev;
457 
458 	bzero(scsicfg, sizeof(struct virtio_scsi_config));
459 
460 	VTSCSI_GET_CONFIG(dev, num_queues, scsicfg);
461 	VTSCSI_GET_CONFIG(dev, seg_max, scsicfg);
462 	VTSCSI_GET_CONFIG(dev, max_sectors, scsicfg);
463 	VTSCSI_GET_CONFIG(dev, cmd_per_lun, scsicfg);
464 	VTSCSI_GET_CONFIG(dev, event_info_size, scsicfg);
465 	VTSCSI_GET_CONFIG(dev, sense_size, scsicfg);
466 	VTSCSI_GET_CONFIG(dev, cdb_size, scsicfg);
467 	VTSCSI_GET_CONFIG(dev, max_channel, scsicfg);
468 	VTSCSI_GET_CONFIG(dev, max_target, scsicfg);
469 	VTSCSI_GET_CONFIG(dev, max_lun, scsicfg);
470 }
471 
472 #undef VTSCSI_GET_CONFIG
473 
474 static int
475 vtscsi_maximum_segments(struct vtscsi_softc *sc, int seg_max)
476 {
477 	int nsegs;
478 
479 	nsegs = VTSCSI_MIN_SEGMENTS;
480 
481 	if (seg_max > 0) {
482 		nsegs += MIN(seg_max, maxphys / PAGE_SIZE + 1);
483 		if (sc->vtscsi_flags & VTSCSI_FLAG_INDIRECT)
484 			nsegs = MIN(nsegs, VIRTIO_MAX_INDIRECT);
485 	} else
486 		nsegs += 1;
487 
488 	return (nsegs);
489 }
490 
491 static int
492 vtscsi_alloc_virtqueues(struct vtscsi_softc *sc)
493 {
494 	device_t dev;
495 	struct vq_alloc_info vq_info[3];
496 	int nvqs;
497 
498 	dev = sc->vtscsi_dev;
499 	nvqs = 3;
500 
501 	VQ_ALLOC_INFO_INIT(&vq_info[0], 0, vtscsi_control_vq_intr, sc,
502 	    &sc->vtscsi_control_vq, "%s control", device_get_nameunit(dev));
503 
504 	VQ_ALLOC_INFO_INIT(&vq_info[1], 0, vtscsi_event_vq_intr, sc,
505 	    &sc->vtscsi_event_vq, "%s event", device_get_nameunit(dev));
506 
507 	VQ_ALLOC_INFO_INIT(&vq_info[2], sc->vtscsi_max_nsegs,
508 	    vtscsi_request_vq_intr, sc, &sc->vtscsi_request_vq,
509 	    "%s request", device_get_nameunit(dev));
510 
511 	return (virtio_alloc_virtqueues(dev, 0, nvqs, vq_info));
512 }
513 
514 static void
515 vtscsi_check_sizes(struct vtscsi_softc *sc)
516 {
517 	int rqsize;
518 
519 	if ((sc->vtscsi_flags & VTSCSI_FLAG_INDIRECT) == 0) {
520 		/*
521 		 * Ensure the assertions in virtqueue_enqueue(),
522 		 * even if the hypervisor reports a bad seg_max.
523 		 */
524 		rqsize = virtqueue_size(sc->vtscsi_request_vq);
525 		if (sc->vtscsi_max_nsegs > rqsize) {
526 			device_printf(sc->vtscsi_dev,
527 			    "clamping seg_max (%d %d)\n", sc->vtscsi_max_nsegs,
528 			    rqsize);
529 			sc->vtscsi_max_nsegs = rqsize;
530 		}
531 	}
532 }
533 
534 static void
535 vtscsi_write_device_config(struct vtscsi_softc *sc)
536 {
537 
538 	virtio_write_dev_config_4(sc->vtscsi_dev,
539 	    offsetof(struct virtio_scsi_config, sense_size),
540 	    VIRTIO_SCSI_SENSE_SIZE);
541 
542 	/*
543 	 * This is the size in the virtio_scsi_cmd_req structure. Note
544 	 * this value (32) is larger than the maximum CAM CDB size (16).
545 	 */
546 	virtio_write_dev_config_4(sc->vtscsi_dev,
547 	    offsetof(struct virtio_scsi_config, cdb_size),
548 	    VIRTIO_SCSI_CDB_SIZE);
549 }
550 
551 static int
552 vtscsi_reinit(struct vtscsi_softc *sc)
553 {
554 	device_t dev;
555 	int error;
556 
557 	dev = sc->vtscsi_dev;
558 
559 	error = virtio_reinit(dev, sc->vtscsi_features);
560 	if (error == 0) {
561 		vtscsi_write_device_config(sc);
562 		virtio_reinit_complete(dev);
563 		vtscsi_reinit_event_vq(sc);
564 
565 		vtscsi_enable_vqs_intr(sc);
566 	}
567 
568 	vtscsi_dprintf(sc, VTSCSI_TRACE, "error=%d\n", error);
569 
570 	return (error);
571 }
572 
573 static int
574 vtscsi_alloc_cam(struct vtscsi_softc *sc)
575 {
576 	device_t dev;
577 	struct cam_devq *devq;
578 	int openings;
579 
580 	dev = sc->vtscsi_dev;
581 	openings = sc->vtscsi_nrequests - VTSCSI_RESERVED_REQUESTS;
582 
583 	devq = cam_simq_alloc(openings);
584 	if (devq == NULL) {
585 		device_printf(dev, "cannot allocate SIM queue\n");
586 		return (ENOMEM);
587 	}
588 
589 	sc->vtscsi_sim = cam_sim_alloc(vtscsi_cam_action, vtscsi_cam_poll,
590 	    "vtscsi", sc, device_get_unit(dev), VTSCSI_MTX(sc), 1,
591 	    openings, devq);
592 	if (sc->vtscsi_sim == NULL) {
593 		cam_simq_free(devq);
594 		device_printf(dev, "cannot allocate SIM\n");
595 		return (ENOMEM);
596 	}
597 
598 	return (0);
599 }
600 
601 static int
602 vtscsi_register_cam(struct vtscsi_softc *sc)
603 {
604 	device_t dev;
605 	int registered, error;
606 
607 	dev = sc->vtscsi_dev;
608 	registered = 0;
609 
610 	VTSCSI_LOCK(sc);
611 
612 	if (xpt_bus_register(sc->vtscsi_sim, dev, 0) != CAM_SUCCESS) {
613 		error = ENOMEM;
614 		device_printf(dev, "cannot register XPT bus\n");
615 		goto fail;
616 	}
617 
618 	registered = 1;
619 
620 	if (xpt_create_path(&sc->vtscsi_path, NULL,
621 	    cam_sim_path(sc->vtscsi_sim), CAM_TARGET_WILDCARD,
622 	    CAM_LUN_WILDCARD) != CAM_REQ_CMP) {
623 		error = ENOMEM;
624 		device_printf(dev, "cannot create bus path\n");
625 		goto fail;
626 	}
627 
628 	if (vtscsi_register_async(sc) != CAM_REQ_CMP) {
629 		error = EIO;
630 		device_printf(dev, "cannot register async callback\n");
631 		goto fail;
632 	}
633 
634 	VTSCSI_UNLOCK(sc);
635 
636 	return (0);
637 
638 fail:
639 	if (sc->vtscsi_path != NULL) {
640 		xpt_free_path(sc->vtscsi_path);
641 		sc->vtscsi_path = NULL;
642 	}
643 
644 	if (registered != 0)
645 		xpt_bus_deregister(cam_sim_path(sc->vtscsi_sim));
646 
647 	VTSCSI_UNLOCK(sc);
648 
649 	return (error);
650 }
651 
652 static void
653 vtscsi_free_cam(struct vtscsi_softc *sc)
654 {
655 
656 	VTSCSI_LOCK(sc);
657 
658 	if (sc->vtscsi_path != NULL) {
659 		vtscsi_deregister_async(sc);
660 
661 		xpt_free_path(sc->vtscsi_path);
662 		sc->vtscsi_path = NULL;
663 
664 		xpt_bus_deregister(cam_sim_path(sc->vtscsi_sim));
665 	}
666 
667 	if (sc->vtscsi_sim != NULL) {
668 		cam_sim_free(sc->vtscsi_sim, 1);
669 		sc->vtscsi_sim = NULL;
670 	}
671 
672 	VTSCSI_UNLOCK(sc);
673 }
674 
675 static void
676 vtscsi_cam_async(void *cb_arg, uint32_t code, struct cam_path *path, void *arg)
677 {
678 	struct cam_sim *sim;
679 	struct vtscsi_softc *sc;
680 
681 	sim = cb_arg;
682 	sc = cam_sim_softc(sim);
683 
684 	vtscsi_dprintf(sc, VTSCSI_TRACE, "code=%u\n", code);
685 
686 	/*
687 	 * TODO Once QEMU supports event reporting, we should
688 	 *      (un)subscribe to events here.
689 	 */
690 	switch (code) {
691 	case AC_FOUND_DEVICE:
692 		break;
693 	case AC_LOST_DEVICE:
694 		break;
695 	}
696 }
697 
698 static int
699 vtscsi_register_async(struct vtscsi_softc *sc)
700 {
701 	struct ccb_setasync csa;
702 
703 	xpt_setup_ccb(&csa.ccb_h, sc->vtscsi_path, 5);
704 	csa.ccb_h.func_code = XPT_SASYNC_CB;
705 	csa.event_enable = AC_LOST_DEVICE | AC_FOUND_DEVICE;
706 	csa.callback = vtscsi_cam_async;
707 	csa.callback_arg = sc->vtscsi_sim;
708 
709 	xpt_action((union ccb *) &csa);
710 
711 	return (csa.ccb_h.status);
712 }
713 
714 static void
715 vtscsi_deregister_async(struct vtscsi_softc *sc)
716 {
717 	struct ccb_setasync csa;
718 
719 	xpt_setup_ccb(&csa.ccb_h, sc->vtscsi_path, 5);
720 	csa.ccb_h.func_code = XPT_SASYNC_CB;
721 	csa.event_enable = 0;
722 	csa.callback = vtscsi_cam_async;
723 	csa.callback_arg = sc->vtscsi_sim;
724 
725 	xpt_action((union ccb *) &csa);
726 }
727 
728 static void
729 vtscsi_cam_action(struct cam_sim *sim, union ccb *ccb)
730 {
731 	struct vtscsi_softc *sc;
732 	struct ccb_hdr *ccbh;
733 
734 	sc = cam_sim_softc(sim);
735 	ccbh = &ccb->ccb_h;
736 
737 	VTSCSI_LOCK_OWNED(sc);
738 
739 	if (sc->vtscsi_flags & VTSCSI_FLAG_DETACH) {
740 		/*
741 		 * The VTSCSI_MTX is briefly dropped between setting
742 		 * VTSCSI_FLAG_DETACH and deregistering with CAM, so
743 		 * drop any CCBs that come in during that window.
744 		 */
745 		ccbh->status = CAM_NO_HBA;
746 		xpt_done(ccb);
747 		return;
748 	}
749 
750 	switch (ccbh->func_code) {
751 	case XPT_SCSI_IO:
752 		vtscsi_cam_scsi_io(sc, sim, ccb);
753 		break;
754 
755 	case XPT_SET_TRAN_SETTINGS:
756 		ccbh->status = CAM_FUNC_NOTAVAIL;
757 		xpt_done(ccb);
758 		break;
759 
760 	case XPT_GET_TRAN_SETTINGS:
761 		vtscsi_cam_get_tran_settings(sc, ccb);
762 		break;
763 
764 	case XPT_RESET_BUS:
765 		vtscsi_cam_reset_bus(sc, ccb);
766 		break;
767 
768 	case XPT_RESET_DEV:
769 		vtscsi_cam_reset_dev(sc, ccb);
770 		break;
771 
772 	case XPT_ABORT:
773 		vtscsi_cam_abort(sc, ccb);
774 		break;
775 
776 	case XPT_CALC_GEOMETRY:
777 		cam_calc_geometry(&ccb->ccg, 1);
778 		xpt_done(ccb);
779 		break;
780 
781 	case XPT_PATH_INQ:
782 		vtscsi_cam_path_inquiry(sc, sim, ccb);
783 		break;
784 
785 	default:
786 		vtscsi_dprintf(sc, VTSCSI_ERROR,
787 		    "invalid ccb=%p func=%#x\n", ccb, ccbh->func_code);
788 
789 		ccbh->status = CAM_REQ_INVALID;
790 		xpt_done(ccb);
791 		break;
792 	}
793 }
794 
795 static void
796 vtscsi_cam_poll(struct cam_sim *sim)
797 {
798 	struct vtscsi_softc *sc;
799 
800 	sc = cam_sim_softc(sim);
801 
802 	vtscsi_complete_vqs_locked(sc);
803 }
804 
805 static void
806 vtscsi_cam_scsi_io(struct vtscsi_softc *sc, struct cam_sim *sim,
807     union ccb *ccb)
808 {
809 	struct ccb_hdr *ccbh;
810 	struct ccb_scsiio *csio;
811 	int error;
812 
813 	ccbh = &ccb->ccb_h;
814 	csio = &ccb->csio;
815 
816 	if (csio->cdb_len > VIRTIO_SCSI_CDB_SIZE) {
817 		error = EINVAL;
818 		ccbh->status = CAM_REQ_INVALID;
819 		goto done;
820 	}
821 
822 	if ((ccbh->flags & CAM_DIR_MASK) == CAM_DIR_BOTH &&
823 	    (sc->vtscsi_flags & VTSCSI_FLAG_BIDIRECTIONAL) == 0) {
824 		error = EINVAL;
825 		ccbh->status = CAM_REQ_INVALID;
826 		goto done;
827 	}
828 
829 	error = vtscsi_start_scsi_cmd(sc, ccb);
830 
831 done:
832 	if (error) {
833 		vtscsi_dprintf(sc, VTSCSI_ERROR,
834 		    "error=%d ccb=%p status=%#x\n", error, ccb, ccbh->status);
835 		xpt_done(ccb);
836 	}
837 }
838 
839 static void
840 vtscsi_cam_get_tran_settings(struct vtscsi_softc *sc, union ccb *ccb)
841 {
842 	struct ccb_trans_settings *cts;
843 	struct ccb_trans_settings_scsi *scsi;
844 
845 	cts = &ccb->cts;
846 	scsi = &cts->proto_specific.scsi;
847 
848 	cts->protocol = PROTO_SCSI;
849 	cts->protocol_version = SCSI_REV_SPC3;
850 	cts->transport = XPORT_SAS;
851 	cts->transport_version = 0;
852 
853 	scsi->valid = CTS_SCSI_VALID_TQ;
854 	scsi->flags = CTS_SCSI_FLAGS_TAG_ENB;
855 
856 	ccb->ccb_h.status = CAM_REQ_CMP;
857 	xpt_done(ccb);
858 }
859 
860 static void
861 vtscsi_cam_reset_bus(struct vtscsi_softc *sc, union ccb *ccb)
862 {
863 	int error;
864 
865 	error = vtscsi_reset_bus(sc);
866 	if (error == 0)
867 		ccb->ccb_h.status = CAM_REQ_CMP;
868 	else
869 		ccb->ccb_h.status = CAM_REQ_CMP_ERR;
870 
871 	vtscsi_dprintf(sc, VTSCSI_TRACE, "error=%d ccb=%p status=%#x\n",
872 	    error, ccb, ccb->ccb_h.status);
873 
874 	xpt_done(ccb);
875 }
876 
877 static void
878 vtscsi_cam_reset_dev(struct vtscsi_softc *sc, union ccb *ccb)
879 {
880 	struct ccb_hdr *ccbh;
881 	struct vtscsi_request *req;
882 	int error;
883 
884 	ccbh = &ccb->ccb_h;
885 
886 	req = vtscsi_dequeue_request(sc);
887 	if (req == NULL) {
888 		error = EAGAIN;
889 		vtscsi_freeze_simq(sc, VTSCSI_REQUEST);
890 		goto fail;
891 	}
892 
893 	req->vsr_ccb = ccb;
894 
895 	error = vtscsi_execute_reset_dev_cmd(sc, req);
896 	if (error == 0)
897 		return;
898 
899 	vtscsi_enqueue_request(sc, req);
900 
901 fail:
902 	vtscsi_dprintf(sc, VTSCSI_ERROR, "error=%d req=%p ccb=%p\n",
903 	    error, req, ccb);
904 
905 	if (error == EAGAIN)
906 		ccbh->status = CAM_RESRC_UNAVAIL;
907 	else
908 		ccbh->status = CAM_REQ_CMP_ERR;
909 
910 	xpt_done(ccb);
911 }
912 
913 static void
914 vtscsi_cam_abort(struct vtscsi_softc *sc, union ccb *ccb)
915 {
916 	struct vtscsi_request *req;
917 	struct ccb_hdr *ccbh;
918 	int error;
919 
920 	ccbh = &ccb->ccb_h;
921 
922 	req = vtscsi_dequeue_request(sc);
923 	if (req == NULL) {
924 		error = EAGAIN;
925 		vtscsi_freeze_simq(sc, VTSCSI_REQUEST);
926 		goto fail;
927 	}
928 
929 	req->vsr_ccb = ccb;
930 
931 	error = vtscsi_execute_abort_task_cmd(sc, req);
932 	if (error == 0)
933 		return;
934 
935 	vtscsi_enqueue_request(sc, req);
936 
937 fail:
938 	vtscsi_dprintf(sc, VTSCSI_ERROR, "error=%d req=%p ccb=%p\n",
939 	    error, req, ccb);
940 
941 	if (error == EAGAIN)
942 		ccbh->status = CAM_RESRC_UNAVAIL;
943 	else
944 		ccbh->status = CAM_REQ_CMP_ERR;
945 
946 	xpt_done(ccb);
947 }
948 
949 static void
950 vtscsi_cam_path_inquiry(struct vtscsi_softc *sc, struct cam_sim *sim,
951     union ccb *ccb)
952 {
953 	device_t dev;
954 	struct ccb_pathinq *cpi;
955 
956 	dev = sc->vtscsi_dev;
957 	cpi = &ccb->cpi;
958 
959 	vtscsi_dprintf(sc, VTSCSI_TRACE, "sim=%p ccb=%p\n", sim, ccb);
960 
961 	cpi->version_num = 1;
962 	cpi->hba_inquiry = PI_TAG_ABLE;
963 	cpi->target_sprt = 0;
964 	cpi->hba_misc = PIM_SEQSCAN | PIM_UNMAPPED;
965 	if (vtscsi_bus_reset_disable != 0)
966 		cpi->hba_misc |= PIM_NOBUSRESET;
967 	cpi->hba_eng_cnt = 0;
968 
969 	cpi->max_target = sc->vtscsi_max_target;
970 	cpi->max_lun = sc->vtscsi_max_lun;
971 	cpi->initiator_id = cpi->max_target + 1;
972 
973 	strlcpy(cpi->sim_vid, "FreeBSD", SIM_IDLEN);
974 	strlcpy(cpi->hba_vid, "VirtIO", HBA_IDLEN);
975 	strlcpy(cpi->dev_name, cam_sim_name(sim), DEV_IDLEN);
976 
977 	cpi->unit_number = cam_sim_unit(sim);
978 	cpi->bus_id = cam_sim_bus(sim);
979 
980 	cpi->base_transfer_speed = 300000;
981 
982 	cpi->protocol = PROTO_SCSI;
983 	cpi->protocol_version = SCSI_REV_SPC3;
984 	cpi->transport = XPORT_SAS;
985 	cpi->transport_version = 0;
986 
987 	cpi->maxio = (sc->vtscsi_max_nsegs - VTSCSI_MIN_SEGMENTS - 1) *
988 	    PAGE_SIZE;
989 
990 	cpi->hba_vendor = virtio_get_vendor(dev);
991 	cpi->hba_device = virtio_get_device(dev);
992 	cpi->hba_subvendor = virtio_get_subvendor(dev);
993 	cpi->hba_subdevice = virtio_get_subdevice(dev);
994 
995 	ccb->ccb_h.status = CAM_REQ_CMP;
996 	xpt_done(ccb);
997 }
998 
999 static int
1000 vtscsi_sg_append_scsi_buf(struct vtscsi_softc *sc, struct sglist *sg,
1001     struct ccb_scsiio *csio)
1002 {
1003 	struct ccb_hdr *ccbh;
1004 	struct bus_dma_segment *dseg;
1005 	int i, error;
1006 
1007 	ccbh = &csio->ccb_h;
1008 	error = 0;
1009 
1010 	switch ((ccbh->flags & CAM_DATA_MASK)) {
1011 	case CAM_DATA_VADDR:
1012 		error = sglist_append(sg, csio->data_ptr, csio->dxfer_len);
1013 		break;
1014 	case CAM_DATA_PADDR:
1015 		error = sglist_append_phys(sg,
1016 		    (vm_paddr_t)(vm_offset_t) csio->data_ptr, csio->dxfer_len);
1017 		break;
1018 	case CAM_DATA_SG:
1019 		for (i = 0; i < csio->sglist_cnt && error == 0; i++) {
1020 			dseg = &((struct bus_dma_segment *)csio->data_ptr)[i];
1021 			error = sglist_append(sg,
1022 			    (void *)(vm_offset_t) dseg->ds_addr, dseg->ds_len);
1023 		}
1024 		break;
1025 	case CAM_DATA_SG_PADDR:
1026 		for (i = 0; i < csio->sglist_cnt && error == 0; i++) {
1027 			dseg = &((struct bus_dma_segment *)csio->data_ptr)[i];
1028 			error = sglist_append_phys(sg,
1029 			    (vm_paddr_t) dseg->ds_addr, dseg->ds_len);
1030 		}
1031 		break;
1032 	case CAM_DATA_BIO:
1033 		error = sglist_append_bio(sg, (struct bio *) csio->data_ptr);
1034 		break;
1035 	default:
1036 		error = EINVAL;
1037 		break;
1038 	}
1039 
1040 	return (error);
1041 }
1042 
1043 static int
1044 vtscsi_fill_scsi_cmd_sglist(struct vtscsi_softc *sc, struct vtscsi_request *req,
1045     int *readable, int *writable)
1046 {
1047 	struct sglist *sg;
1048 	struct ccb_hdr *ccbh;
1049 	struct ccb_scsiio *csio;
1050 	struct virtio_scsi_cmd_req *cmd_req;
1051 	struct virtio_scsi_cmd_resp *cmd_resp;
1052 	int error;
1053 
1054 	sg = sc->vtscsi_sglist;
1055 	csio = &req->vsr_ccb->csio;
1056 	ccbh = &csio->ccb_h;
1057 	cmd_req = &req->vsr_cmd_req;
1058 	cmd_resp = &req->vsr_cmd_resp;
1059 
1060 	sglist_reset(sg);
1061 
1062 	sglist_append(sg, cmd_req, sizeof(struct virtio_scsi_cmd_req));
1063 	if ((ccbh->flags & CAM_DIR_MASK) == CAM_DIR_OUT) {
1064 		error = vtscsi_sg_append_scsi_buf(sc, sg, csio);
1065 		/* At least one segment must be left for the response. */
1066 		if (error || sg->sg_nseg == sg->sg_maxseg)
1067 			goto fail;
1068 	}
1069 
1070 	*readable = sg->sg_nseg;
1071 
1072 	sglist_append(sg, cmd_resp, sizeof(struct virtio_scsi_cmd_resp));
1073 	if ((ccbh->flags & CAM_DIR_MASK) == CAM_DIR_IN) {
1074 		error = vtscsi_sg_append_scsi_buf(sc, sg, csio);
1075 		if (error)
1076 			goto fail;
1077 	}
1078 
1079 	*writable = sg->sg_nseg - *readable;
1080 
1081 	vtscsi_dprintf(sc, VTSCSI_TRACE, "req=%p ccb=%p readable=%d "
1082 	    "writable=%d\n", req, ccbh, *readable, *writable);
1083 
1084 	return (0);
1085 
1086 fail:
1087 	/*
1088 	 * This should never happen unless maxio was incorrectly set.
1089 	 */
1090 	vtscsi_set_ccb_status(ccbh, CAM_REQ_TOO_BIG, 0);
1091 
1092 	vtscsi_dprintf(sc, VTSCSI_ERROR, "error=%d req=%p ccb=%p "
1093 	    "nseg=%d maxseg=%d\n",
1094 	    error, req, ccbh, sg->sg_nseg, sg->sg_maxseg);
1095 
1096 	return (EFBIG);
1097 }
1098 
1099 static int
1100 vtscsi_execute_scsi_cmd(struct vtscsi_softc *sc, struct vtscsi_request *req)
1101 {
1102 	struct sglist *sg;
1103 	struct virtqueue *vq;
1104 	struct ccb_scsiio *csio;
1105 	struct ccb_hdr *ccbh;
1106 	struct virtio_scsi_cmd_req *cmd_req;
1107 	struct virtio_scsi_cmd_resp *cmd_resp;
1108 	int readable, writable, error;
1109 
1110 	sg = sc->vtscsi_sglist;
1111 	vq = sc->vtscsi_request_vq;
1112 	csio = &req->vsr_ccb->csio;
1113 	ccbh = &csio->ccb_h;
1114 	cmd_req = &req->vsr_cmd_req;
1115 	cmd_resp = &req->vsr_cmd_resp;
1116 
1117 	vtscsi_init_scsi_cmd_req(sc, csio, cmd_req);
1118 
1119 	error = vtscsi_fill_scsi_cmd_sglist(sc, req, &readable, &writable);
1120 	if (error)
1121 		return (error);
1122 
1123 	req->vsr_complete = vtscsi_complete_scsi_cmd;
1124 	cmd_resp->response = -1;
1125 
1126 	error = virtqueue_enqueue(vq, req, sg, readable, writable);
1127 	if (error) {
1128 		vtscsi_dprintf(sc, VTSCSI_ERROR,
1129 		    "enqueue error=%d req=%p ccb=%p\n", error, req, ccbh);
1130 
1131 		ccbh->status = CAM_REQUEUE_REQ;
1132 		vtscsi_freeze_simq(sc, VTSCSI_REQUEST_VQ);
1133 		return (error);
1134 	}
1135 
1136 	ccbh->status |= CAM_SIM_QUEUED;
1137 	ccbh->ccbh_vtscsi_req = req;
1138 
1139 	virtqueue_notify(vq);
1140 
1141 	if (ccbh->timeout != CAM_TIME_INFINITY) {
1142 		req->vsr_flags |= VTSCSI_REQ_FLAG_TIMEOUT_SET;
1143 		callout_reset_sbt(&req->vsr_callout, SBT_1MS * ccbh->timeout,
1144 		    0, vtscsi_timedout_scsi_cmd, req, 0);
1145 	}
1146 
1147 	vtscsi_dprintf_req(req, VTSCSI_TRACE, "enqueued req=%p ccb=%p\n",
1148 	    req, ccbh);
1149 
1150 	return (0);
1151 }
1152 
1153 static int
1154 vtscsi_start_scsi_cmd(struct vtscsi_softc *sc, union ccb *ccb)
1155 {
1156 	struct vtscsi_request *req;
1157 	int error;
1158 
1159 	req = vtscsi_dequeue_request(sc);
1160 	if (req == NULL) {
1161 		ccb->ccb_h.status = CAM_REQUEUE_REQ;
1162 		vtscsi_freeze_simq(sc, VTSCSI_REQUEST);
1163 		return (ENOBUFS);
1164 	}
1165 
1166 	req->vsr_ccb = ccb;
1167 
1168 	error = vtscsi_execute_scsi_cmd(sc, req);
1169 	if (error)
1170 		vtscsi_enqueue_request(sc, req);
1171 
1172 	return (error);
1173 }
1174 
1175 static void
1176 vtscsi_complete_abort_timedout_scsi_cmd(struct vtscsi_softc *sc,
1177     struct vtscsi_request *req)
1178 {
1179 	struct virtio_scsi_ctrl_tmf_resp *tmf_resp;
1180 	struct vtscsi_request *to_req;
1181 	uint8_t response;
1182 
1183 	tmf_resp = &req->vsr_tmf_resp;
1184 	response = tmf_resp->response;
1185 	to_req = req->vsr_timedout_req;
1186 
1187 	vtscsi_dprintf(sc, VTSCSI_TRACE, "req=%p to_req=%p response=%d\n",
1188 	    req, to_req, response);
1189 
1190 	vtscsi_enqueue_request(sc, req);
1191 
1192 	/*
1193 	 * The timedout request could have completed between when the
1194 	 * abort task was sent and when the host processed it.
1195 	 */
1196 	if (to_req->vsr_state != VTSCSI_REQ_STATE_TIMEDOUT)
1197 		return;
1198 
1199 	/* The timedout request was successfully aborted. */
1200 	if (response == VIRTIO_SCSI_S_FUNCTION_COMPLETE)
1201 		return;
1202 
1203 	/* Don't bother if the device is going away. */
1204 	if (sc->vtscsi_flags & VTSCSI_FLAG_DETACH)
1205 		return;
1206 
1207 	/* The timedout request will be aborted by the reset. */
1208 	if (sc->vtscsi_flags & VTSCSI_FLAG_RESET)
1209 		return;
1210 
1211 	vtscsi_reset_bus(sc);
1212 }
1213 
1214 static int
1215 vtscsi_abort_timedout_scsi_cmd(struct vtscsi_softc *sc,
1216     struct vtscsi_request *to_req)
1217 {
1218 	struct sglist *sg;
1219 	struct ccb_hdr *to_ccbh;
1220 	struct vtscsi_request *req;
1221 	struct virtio_scsi_ctrl_tmf_req *tmf_req;
1222 	struct virtio_scsi_ctrl_tmf_resp *tmf_resp;
1223 	int error;
1224 
1225 	sg = sc->vtscsi_sglist;
1226 	to_ccbh = &to_req->vsr_ccb->ccb_h;
1227 
1228 	req = vtscsi_dequeue_request(sc);
1229 	if (req == NULL) {
1230 		error = ENOBUFS;
1231 		goto fail;
1232 	}
1233 
1234 	tmf_req = &req->vsr_tmf_req;
1235 	tmf_resp = &req->vsr_tmf_resp;
1236 
1237 	vtscsi_init_ctrl_tmf_req(sc, to_ccbh, VIRTIO_SCSI_T_TMF_ABORT_TASK,
1238 	    (uintptr_t) to_ccbh, tmf_req);
1239 
1240 	sglist_reset(sg);
1241 	sglist_append(sg, tmf_req, sizeof(struct virtio_scsi_ctrl_tmf_req));
1242 	sglist_append(sg, tmf_resp, sizeof(struct virtio_scsi_ctrl_tmf_resp));
1243 
1244 	req->vsr_timedout_req = to_req;
1245 	req->vsr_complete = vtscsi_complete_abort_timedout_scsi_cmd;
1246 	tmf_resp->response = -1;
1247 
1248 	error = vtscsi_execute_ctrl_req(sc, req, sg, 1, 1,
1249 	    VTSCSI_EXECUTE_ASYNC);
1250 	if (error == 0)
1251 		return (0);
1252 
1253 	vtscsi_enqueue_request(sc, req);
1254 
1255 fail:
1256 	vtscsi_dprintf(sc, VTSCSI_ERROR, "error=%d req=%p "
1257 	    "timedout req=%p ccb=%p\n", error, req, to_req, to_ccbh);
1258 
1259 	return (error);
1260 }
1261 
1262 static void
1263 vtscsi_timedout_scsi_cmd(void *xreq)
1264 {
1265 	struct vtscsi_softc *sc;
1266 	struct vtscsi_request *to_req;
1267 
1268 	to_req = xreq;
1269 	sc = to_req->vsr_softc;
1270 
1271 	vtscsi_dprintf(sc, VTSCSI_INFO, "timedout req=%p ccb=%p state=%#x\n",
1272 	    to_req, to_req->vsr_ccb, to_req->vsr_state);
1273 
1274 	/* Don't bother if the device is going away. */
1275 	if (sc->vtscsi_flags & VTSCSI_FLAG_DETACH)
1276 		return;
1277 
1278 	/*
1279 	 * Bail if the request is not in use. We likely raced when
1280 	 * stopping the callout handler or it has already been aborted.
1281 	 */
1282 	if (to_req->vsr_state != VTSCSI_REQ_STATE_INUSE ||
1283 	    (to_req->vsr_flags & VTSCSI_REQ_FLAG_TIMEOUT_SET) == 0)
1284 		return;
1285 
1286 	/*
1287 	 * Complete the request queue in case the timedout request is
1288 	 * actually just pending.
1289 	 */
1290 	vtscsi_complete_vq(sc, sc->vtscsi_request_vq);
1291 	if (to_req->vsr_state == VTSCSI_REQ_STATE_FREE)
1292 		return;
1293 
1294 	sc->vtscsi_stats.scsi_cmd_timeouts++;
1295 	to_req->vsr_state = VTSCSI_REQ_STATE_TIMEDOUT;
1296 
1297 	if (vtscsi_abort_timedout_scsi_cmd(sc, to_req) == 0)
1298 		return;
1299 
1300 	vtscsi_dprintf(sc, VTSCSI_ERROR, "resetting bus\n");
1301 	vtscsi_reset_bus(sc);
1302 }
1303 
1304 static cam_status
1305 vtscsi_scsi_cmd_cam_status(struct virtio_scsi_cmd_resp *cmd_resp)
1306 {
1307 	cam_status status;
1308 
1309 	switch (cmd_resp->response) {
1310 	case VIRTIO_SCSI_S_OK:
1311 		status = CAM_REQ_CMP;
1312 		break;
1313 	case VIRTIO_SCSI_S_OVERRUN:
1314 		status = CAM_DATA_RUN_ERR;
1315 		break;
1316 	case VIRTIO_SCSI_S_ABORTED:
1317 		status = CAM_REQ_ABORTED;
1318 		break;
1319 	case VIRTIO_SCSI_S_BAD_TARGET:
1320 		status = CAM_SEL_TIMEOUT;
1321 		break;
1322 	case VIRTIO_SCSI_S_RESET:
1323 		status = CAM_SCSI_BUS_RESET;
1324 		break;
1325 	case VIRTIO_SCSI_S_BUSY:
1326 		status = CAM_SCSI_BUSY;
1327 		break;
1328 	case VIRTIO_SCSI_S_TRANSPORT_FAILURE:
1329 	case VIRTIO_SCSI_S_TARGET_FAILURE:
1330 	case VIRTIO_SCSI_S_NEXUS_FAILURE:
1331 		status = CAM_SCSI_IT_NEXUS_LOST;
1332 		break;
1333 	default: /* VIRTIO_SCSI_S_FAILURE */
1334 		status = CAM_REQ_CMP_ERR;
1335 		break;
1336 	}
1337 
1338 	return (status);
1339 }
1340 
1341 static cam_status
1342 vtscsi_complete_scsi_cmd_response(struct vtscsi_softc *sc,
1343     struct ccb_scsiio *csio, struct virtio_scsi_cmd_resp *cmd_resp)
1344 {
1345 	uint32_t resp_sense_length;
1346 	cam_status status;
1347 
1348 	csio->scsi_status = cmd_resp->status;
1349 	csio->resid = vtscsi_htog32(sc, cmd_resp->resid);
1350 
1351 	if (csio->scsi_status == SCSI_STATUS_OK)
1352 		status = CAM_REQ_CMP;
1353 	else
1354 		status = CAM_SCSI_STATUS_ERROR;
1355 
1356 	resp_sense_length = vtscsi_htog32(sc, cmd_resp->sense_len);
1357 
1358 	if (resp_sense_length > 0) {
1359 		status |= CAM_AUTOSNS_VALID;
1360 
1361 		if (resp_sense_length < csio->sense_len)
1362 			csio->sense_resid = csio->sense_len - resp_sense_length;
1363 		else
1364 			csio->sense_resid = 0;
1365 
1366 		memcpy(&csio->sense_data, cmd_resp->sense,
1367 		    csio->sense_len - csio->sense_resid);
1368 	}
1369 
1370 	vtscsi_dprintf(sc, status == CAM_REQ_CMP ? VTSCSI_TRACE : VTSCSI_ERROR,
1371 	    "ccb=%p scsi_status=%#x resid=%u sense_resid=%u\n",
1372 	    csio, csio->scsi_status, csio->resid, csio->sense_resid);
1373 
1374 	return (status);
1375 }
1376 
1377 static void
1378 vtscsi_complete_scsi_cmd(struct vtscsi_softc *sc, struct vtscsi_request *req)
1379 {
1380 	struct ccb_hdr *ccbh;
1381 	struct ccb_scsiio *csio;
1382 	struct virtio_scsi_cmd_resp *cmd_resp;
1383 	cam_status status;
1384 
1385 	csio = &req->vsr_ccb->csio;
1386 	ccbh = &csio->ccb_h;
1387 	cmd_resp = &req->vsr_cmd_resp;
1388 
1389 	KASSERT(ccbh->ccbh_vtscsi_req == req,
1390 	    ("ccb %p req mismatch %p/%p", ccbh, ccbh->ccbh_vtscsi_req, req));
1391 
1392 	if (req->vsr_flags & VTSCSI_REQ_FLAG_TIMEOUT_SET)
1393 		callout_stop(&req->vsr_callout);
1394 
1395 	status = vtscsi_scsi_cmd_cam_status(cmd_resp);
1396 	if (status == CAM_REQ_ABORTED) {
1397 		if (req->vsr_state == VTSCSI_REQ_STATE_TIMEDOUT)
1398 			status = CAM_CMD_TIMEOUT;
1399 	} else if (status == CAM_REQ_CMP)
1400 		status = vtscsi_complete_scsi_cmd_response(sc, csio, cmd_resp);
1401 
1402 	if ((status & CAM_STATUS_MASK) != CAM_REQ_CMP) {
1403 		status |= CAM_DEV_QFRZN;
1404 		xpt_freeze_devq(ccbh->path, 1);
1405 	}
1406 
1407 	if (vtscsi_thaw_simq(sc, VTSCSI_REQUEST | VTSCSI_REQUEST_VQ) != 0)
1408 		status |= CAM_RELEASE_SIMQ;
1409 
1410 	vtscsi_dprintf(sc, VTSCSI_TRACE, "req=%p ccb=%p status=%#x\n",
1411 	    req, ccbh, status);
1412 
1413 	ccbh->status = status;
1414 	xpt_done(req->vsr_ccb);
1415 	vtscsi_enqueue_request(sc, req);
1416 }
1417 
1418 static void
1419 vtscsi_poll_ctrl_req(struct vtscsi_softc *sc, struct vtscsi_request *req)
1420 {
1421 
1422 	/* XXX We probably shouldn't poll forever. */
1423 	req->vsr_flags |= VTSCSI_REQ_FLAG_POLLED;
1424 	do
1425 		vtscsi_complete_vq(sc, sc->vtscsi_control_vq);
1426 	while ((req->vsr_flags & VTSCSI_REQ_FLAG_COMPLETE) == 0);
1427 
1428 	req->vsr_flags &= ~VTSCSI_REQ_FLAG_POLLED;
1429 }
1430 
1431 static int
1432 vtscsi_execute_ctrl_req(struct vtscsi_softc *sc, struct vtscsi_request *req,
1433     struct sglist *sg, int readable, int writable, int flag)
1434 {
1435 	struct virtqueue *vq;
1436 	int error;
1437 
1438 	vq = sc->vtscsi_control_vq;
1439 
1440 	MPASS(flag == VTSCSI_EXECUTE_POLL || req->vsr_complete != NULL);
1441 
1442 	error = virtqueue_enqueue(vq, req, sg, readable, writable);
1443 	if (error) {
1444 		/*
1445 		 * Return EAGAIN when the virtqueue does not have enough
1446 		 * descriptors available.
1447 		 */
1448 		if (error == ENOSPC || error == EMSGSIZE)
1449 			error = EAGAIN;
1450 
1451 		return (error);
1452 	}
1453 
1454 	virtqueue_notify(vq);
1455 	if (flag == VTSCSI_EXECUTE_POLL)
1456 		vtscsi_poll_ctrl_req(sc, req);
1457 
1458 	return (0);
1459 }
1460 
1461 static void
1462 vtscsi_complete_abort_task_cmd(struct vtscsi_softc *sc,
1463     struct vtscsi_request *req)
1464 {
1465 	union ccb *ccb;
1466 	struct ccb_hdr *ccbh;
1467 	struct virtio_scsi_ctrl_tmf_resp *tmf_resp;
1468 
1469 	ccb = req->vsr_ccb;
1470 	ccbh = &ccb->ccb_h;
1471 	tmf_resp = &req->vsr_tmf_resp;
1472 
1473 	switch (tmf_resp->response) {
1474 	case VIRTIO_SCSI_S_FUNCTION_COMPLETE:
1475 		ccbh->status = CAM_REQ_CMP;
1476 		break;
1477 	case VIRTIO_SCSI_S_FUNCTION_REJECTED:
1478 		ccbh->status = CAM_UA_ABORT;
1479 		break;
1480 	default:
1481 		ccbh->status = CAM_REQ_CMP_ERR;
1482 		break;
1483 	}
1484 
1485 	xpt_done(ccb);
1486 	vtscsi_enqueue_request(sc, req);
1487 }
1488 
1489 static int
1490 vtscsi_execute_abort_task_cmd(struct vtscsi_softc *sc,
1491     struct vtscsi_request *req)
1492 {
1493 	struct sglist *sg;
1494 	struct ccb_abort *cab;
1495 	struct ccb_hdr *ccbh;
1496 	struct ccb_hdr *abort_ccbh;
1497 	struct vtscsi_request *abort_req;
1498 	struct virtio_scsi_ctrl_tmf_req *tmf_req;
1499 	struct virtio_scsi_ctrl_tmf_resp *tmf_resp;
1500 	int error;
1501 
1502 	sg = sc->vtscsi_sglist;
1503 	cab = &req->vsr_ccb->cab;
1504 	ccbh = &cab->ccb_h;
1505 	tmf_req = &req->vsr_tmf_req;
1506 	tmf_resp = &req->vsr_tmf_resp;
1507 
1508 	/* CCB header and request that's to be aborted. */
1509 	abort_ccbh = &cab->abort_ccb->ccb_h;
1510 	abort_req = abort_ccbh->ccbh_vtscsi_req;
1511 
1512 	if (abort_ccbh->func_code != XPT_SCSI_IO || abort_req == NULL) {
1513 		error = EINVAL;
1514 		goto fail;
1515 	}
1516 
1517 	/* Only attempt to abort requests that could be in-flight. */
1518 	if (abort_req->vsr_state != VTSCSI_REQ_STATE_INUSE) {
1519 		error = EALREADY;
1520 		goto fail;
1521 	}
1522 
1523 	abort_req->vsr_state = VTSCSI_REQ_STATE_ABORTED;
1524 	if (abort_req->vsr_flags & VTSCSI_REQ_FLAG_TIMEOUT_SET)
1525 		callout_stop(&abort_req->vsr_callout);
1526 
1527 	vtscsi_init_ctrl_tmf_req(sc, ccbh, VIRTIO_SCSI_T_TMF_ABORT_TASK,
1528 	    (uintptr_t) abort_ccbh, tmf_req);
1529 
1530 	sglist_reset(sg);
1531 	sglist_append(sg, tmf_req, sizeof(struct virtio_scsi_ctrl_tmf_req));
1532 	sglist_append(sg, tmf_resp, sizeof(struct virtio_scsi_ctrl_tmf_resp));
1533 
1534 	req->vsr_complete = vtscsi_complete_abort_task_cmd;
1535 	tmf_resp->response = -1;
1536 
1537 	error = vtscsi_execute_ctrl_req(sc, req, sg, 1, 1,
1538 	    VTSCSI_EXECUTE_ASYNC);
1539 
1540 fail:
1541 	vtscsi_dprintf(sc, VTSCSI_TRACE, "error=%d req=%p abort_ccb=%p "
1542 	    "abort_req=%p\n", error, req, abort_ccbh, abort_req);
1543 
1544 	return (error);
1545 }
1546 
1547 static void
1548 vtscsi_complete_reset_dev_cmd(struct vtscsi_softc *sc,
1549     struct vtscsi_request *req)
1550 {
1551 	union ccb *ccb;
1552 	struct ccb_hdr *ccbh;
1553 	struct virtio_scsi_ctrl_tmf_resp *tmf_resp;
1554 
1555 	ccb = req->vsr_ccb;
1556 	ccbh = &ccb->ccb_h;
1557 	tmf_resp = &req->vsr_tmf_resp;
1558 
1559 	vtscsi_dprintf(sc, VTSCSI_TRACE, "req=%p ccb=%p response=%d\n",
1560 	    req, ccb, tmf_resp->response);
1561 
1562 	if (tmf_resp->response == VIRTIO_SCSI_S_FUNCTION_COMPLETE) {
1563 		ccbh->status = CAM_REQ_CMP;
1564 		vtscsi_announce(sc, AC_SENT_BDR, ccbh->target_id,
1565 		    ccbh->target_lun);
1566 	} else
1567 		ccbh->status = CAM_REQ_CMP_ERR;
1568 
1569 	xpt_done(ccb);
1570 	vtscsi_enqueue_request(sc, req);
1571 }
1572 
1573 static int
1574 vtscsi_execute_reset_dev_cmd(struct vtscsi_softc *sc,
1575     struct vtscsi_request *req)
1576 {
1577 	struct sglist *sg;
1578 	struct ccb_resetdev *crd;
1579 	struct ccb_hdr *ccbh;
1580 	struct virtio_scsi_ctrl_tmf_req *tmf_req;
1581 	struct virtio_scsi_ctrl_tmf_resp *tmf_resp;
1582 	uint32_t subtype;
1583 	int error;
1584 
1585 	sg = sc->vtscsi_sglist;
1586 	crd = &req->vsr_ccb->crd;
1587 	ccbh = &crd->ccb_h;
1588 	tmf_req = &req->vsr_tmf_req;
1589 	tmf_resp = &req->vsr_tmf_resp;
1590 
1591 	if (ccbh->target_lun == CAM_LUN_WILDCARD)
1592 		subtype = VIRTIO_SCSI_T_TMF_I_T_NEXUS_RESET;
1593 	else
1594 		subtype = VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET;
1595 
1596 	vtscsi_init_ctrl_tmf_req(sc, ccbh, subtype, 0, tmf_req);
1597 
1598 	sglist_reset(sg);
1599 	sglist_append(sg, tmf_req, sizeof(struct virtio_scsi_ctrl_tmf_req));
1600 	sglist_append(sg, tmf_resp, sizeof(struct virtio_scsi_ctrl_tmf_resp));
1601 
1602 	req->vsr_complete = vtscsi_complete_reset_dev_cmd;
1603 	tmf_resp->response = -1;
1604 
1605 	error = vtscsi_execute_ctrl_req(sc, req, sg, 1, 1,
1606 	    VTSCSI_EXECUTE_ASYNC);
1607 
1608 	vtscsi_dprintf(sc, VTSCSI_TRACE, "error=%d req=%p ccb=%p\n",
1609 	    error, req, ccbh);
1610 
1611 	return (error);
1612 }
1613 
1614 static void
1615 vtscsi_get_request_lun(uint8_t lun[], target_id_t *target_id, lun_id_t *lun_id)
1616 {
1617 
1618 	*target_id = lun[1];
1619 	*lun_id = (lun[2] << 8) | lun[3];
1620 }
1621 
1622 static void
1623 vtscsi_set_request_lun(struct ccb_hdr *ccbh, uint8_t lun[])
1624 {
1625 
1626 	lun[0] = 1;
1627 	lun[1] = ccbh->target_id;
1628 	lun[2] = 0x40 | ((ccbh->target_lun >> 8) & 0x3F);
1629 	lun[3] = ccbh->target_lun & 0xFF;
1630 }
1631 
1632 static void
1633 vtscsi_init_scsi_cmd_req(struct vtscsi_softc *sc, struct ccb_scsiio *csio,
1634     struct virtio_scsi_cmd_req *cmd_req)
1635 {
1636 	uint8_t attr;
1637 
1638 	switch (csio->tag_action) {
1639 	case MSG_HEAD_OF_Q_TAG:
1640 		attr = VIRTIO_SCSI_S_HEAD;
1641 		break;
1642 	case MSG_ORDERED_Q_TAG:
1643 		attr = VIRTIO_SCSI_S_ORDERED;
1644 		break;
1645 	case MSG_ACA_TASK:
1646 		attr = VIRTIO_SCSI_S_ACA;
1647 		break;
1648 	default: /* MSG_SIMPLE_Q_TAG */
1649 		attr = VIRTIO_SCSI_S_SIMPLE;
1650 		break;
1651 	}
1652 
1653 	vtscsi_set_request_lun(&csio->ccb_h, cmd_req->lun);
1654 	cmd_req->tag = vtscsi_gtoh64(sc, (uintptr_t) csio);
1655 	cmd_req->task_attr = attr;
1656 
1657 	memcpy(cmd_req->cdb,
1658 	    csio->ccb_h.flags & CAM_CDB_POINTER ?
1659 	        csio->cdb_io.cdb_ptr : csio->cdb_io.cdb_bytes,
1660 	    csio->cdb_len);
1661 }
1662 
1663 static void
1664 vtscsi_init_ctrl_tmf_req(struct vtscsi_softc *sc, struct ccb_hdr *ccbh,
1665     uint32_t subtype, uintptr_t tag, struct virtio_scsi_ctrl_tmf_req *tmf_req)
1666 {
1667 
1668 	vtscsi_set_request_lun(ccbh, tmf_req->lun);
1669 
1670 	tmf_req->type = vtscsi_gtoh32(sc, VIRTIO_SCSI_T_TMF);
1671 	tmf_req->subtype = vtscsi_gtoh32(sc, subtype);
1672 	tmf_req->tag = vtscsi_gtoh64(sc, tag);
1673 }
1674 
1675 static void
1676 vtscsi_freeze_simq(struct vtscsi_softc *sc, int reason)
1677 {
1678 	int frozen;
1679 
1680 	frozen = sc->vtscsi_frozen;
1681 
1682 	if (reason & VTSCSI_REQUEST &&
1683 	    (sc->vtscsi_frozen & VTSCSI_FROZEN_NO_REQUESTS) == 0)
1684 		sc->vtscsi_frozen |= VTSCSI_FROZEN_NO_REQUESTS;
1685 
1686 	if (reason & VTSCSI_REQUEST_VQ &&
1687 	    (sc->vtscsi_frozen & VTSCSI_FROZEN_REQUEST_VQ_FULL) == 0)
1688 		sc->vtscsi_frozen |= VTSCSI_FROZEN_REQUEST_VQ_FULL;
1689 
1690 	/* Freeze the SIMQ if transitioned to frozen. */
1691 	if (frozen == 0 && sc->vtscsi_frozen != 0) {
1692 		vtscsi_dprintf(sc, VTSCSI_INFO, "SIMQ frozen\n");
1693 		xpt_freeze_simq(sc->vtscsi_sim, 1);
1694 	}
1695 }
1696 
1697 static int
1698 vtscsi_thaw_simq(struct vtscsi_softc *sc, int reason)
1699 {
1700 	int thawed;
1701 
1702 	if (sc->vtscsi_frozen == 0 || reason == 0)
1703 		return (0);
1704 
1705 	if (reason & VTSCSI_REQUEST &&
1706 	    sc->vtscsi_frozen & VTSCSI_FROZEN_NO_REQUESTS)
1707 		sc->vtscsi_frozen &= ~VTSCSI_FROZEN_NO_REQUESTS;
1708 
1709 	if (reason & VTSCSI_REQUEST_VQ &&
1710 	    sc->vtscsi_frozen & VTSCSI_FROZEN_REQUEST_VQ_FULL)
1711 		sc->vtscsi_frozen &= ~VTSCSI_FROZEN_REQUEST_VQ_FULL;
1712 
1713 	thawed = sc->vtscsi_frozen == 0;
1714 	if (thawed != 0)
1715 		vtscsi_dprintf(sc, VTSCSI_INFO, "SIMQ thawed\n");
1716 
1717 	return (thawed);
1718 }
1719 
1720 static void
1721 vtscsi_announce(struct vtscsi_softc *sc, uint32_t ac_code,
1722     target_id_t target_id, lun_id_t lun_id)
1723 {
1724 	struct cam_path *path;
1725 
1726 	/* Use the wildcard path from our softc for bus announcements. */
1727 	if (target_id == CAM_TARGET_WILDCARD && lun_id == CAM_LUN_WILDCARD) {
1728 		xpt_async(ac_code, sc->vtscsi_path, NULL);
1729 		return;
1730 	}
1731 
1732 	if (xpt_create_path(&path, NULL, cam_sim_path(sc->vtscsi_sim),
1733 	    target_id, lun_id) != CAM_REQ_CMP) {
1734 		vtscsi_dprintf(sc, VTSCSI_ERROR, "cannot create path\n");
1735 		return;
1736 	}
1737 
1738 	xpt_async(ac_code, path, NULL);
1739 	xpt_free_path(path);
1740 }
1741 
1742 static void
1743 vtscsi_execute_rescan(struct vtscsi_softc *sc, target_id_t target_id,
1744     lun_id_t lun_id)
1745 {
1746 	union ccb *ccb;
1747 	cam_status status;
1748 
1749 	ccb = xpt_alloc_ccb_nowait();
1750 	if (ccb == NULL) {
1751 		vtscsi_dprintf(sc, VTSCSI_ERROR, "cannot allocate CCB\n");
1752 		return;
1753 	}
1754 
1755 	status = xpt_create_path(&ccb->ccb_h.path, NULL,
1756 	    cam_sim_path(sc->vtscsi_sim), target_id, lun_id);
1757 	if (status != CAM_REQ_CMP) {
1758 		xpt_free_ccb(ccb);
1759 		return;
1760 	}
1761 
1762 	xpt_rescan(ccb);
1763 }
1764 
1765 static void
1766 vtscsi_execute_rescan_bus(struct vtscsi_softc *sc)
1767 {
1768 
1769 	vtscsi_execute_rescan(sc, CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
1770 }
1771 
1772 static void
1773 vtscsi_transport_reset_event(struct vtscsi_softc *sc,
1774     struct virtio_scsi_event *event)
1775 {
1776 	target_id_t target_id;
1777 	lun_id_t lun_id;
1778 
1779 	vtscsi_get_request_lun(event->lun, &target_id, &lun_id);
1780 
1781 	switch (event->reason) {
1782 	case VIRTIO_SCSI_EVT_RESET_RESCAN:
1783 	case VIRTIO_SCSI_EVT_RESET_REMOVED:
1784 		vtscsi_execute_rescan(sc, target_id, lun_id);
1785 		break;
1786 	default:
1787 		device_printf(sc->vtscsi_dev,
1788 		    "unhandled transport event reason: %d\n", event->reason);
1789 		break;
1790 	}
1791 }
1792 
1793 static void
1794 vtscsi_handle_event(struct vtscsi_softc *sc, struct virtio_scsi_event *event)
1795 {
1796 	int error;
1797 
1798 	if ((event->event & VIRTIO_SCSI_T_EVENTS_MISSED) == 0) {
1799 		switch (event->event) {
1800 		case VIRTIO_SCSI_T_TRANSPORT_RESET:
1801 			vtscsi_transport_reset_event(sc, event);
1802 			break;
1803 		default:
1804 			device_printf(sc->vtscsi_dev,
1805 			    "unhandled event: %d\n", event->event);
1806 			break;
1807 		}
1808 	} else
1809 		vtscsi_execute_rescan_bus(sc);
1810 
1811 	/*
1812 	 * This should always be successful since the buffer
1813 	 * was just dequeued.
1814 	 */
1815 	error = vtscsi_enqueue_event_buf(sc, event);
1816 	KASSERT(error == 0,
1817 	    ("cannot requeue event buffer: %d", error));
1818 }
1819 
1820 static int
1821 vtscsi_enqueue_event_buf(struct vtscsi_softc *sc,
1822     struct virtio_scsi_event *event)
1823 {
1824 	struct sglist *sg;
1825 	struct virtqueue *vq;
1826 	int size, error;
1827 
1828 	sg = sc->vtscsi_sglist;
1829 	vq = sc->vtscsi_event_vq;
1830 	size = sc->vtscsi_event_buf_size;
1831 
1832 	bzero(event, size);
1833 
1834 	sglist_reset(sg);
1835 	error = sglist_append(sg, event, size);
1836 	if (error)
1837 		return (error);
1838 
1839 	error = virtqueue_enqueue(vq, event, sg, 0, sg->sg_nseg);
1840 	if (error)
1841 		return (error);
1842 
1843 	virtqueue_notify(vq);
1844 
1845 	return (0);
1846 }
1847 
1848 static int
1849 vtscsi_init_event_vq(struct vtscsi_softc *sc)
1850 {
1851 	struct virtio_scsi_event *event;
1852 	int i, size, error;
1853 
1854 	/*
1855 	 * The first release of QEMU with VirtIO SCSI support would crash
1856 	 * when attempting to notify the event virtqueue. This was fixed
1857 	 * when hotplug support was added.
1858 	 */
1859 	if (sc->vtscsi_flags & VTSCSI_FLAG_HOTPLUG)
1860 		size = sc->vtscsi_event_buf_size;
1861 	else
1862 		size = 0;
1863 
1864 	if (size < sizeof(struct virtio_scsi_event))
1865 		return (0);
1866 
1867 	for (i = 0; i < VTSCSI_NUM_EVENT_BUFS; i++) {
1868 		event = &sc->vtscsi_event_bufs[i];
1869 
1870 		error = vtscsi_enqueue_event_buf(sc, event);
1871 		if (error)
1872 			break;
1873 	}
1874 
1875 	/*
1876 	 * Even just one buffer is enough. Missed events are
1877 	 * denoted with the VIRTIO_SCSI_T_EVENTS_MISSED flag.
1878 	 */
1879 	if (i > 0)
1880 		error = 0;
1881 
1882 	return (error);
1883 }
1884 
1885 static void
1886 vtscsi_reinit_event_vq(struct vtscsi_softc *sc)
1887 {
1888 	struct virtio_scsi_event *event;
1889 	int i, error;
1890 
1891 	if ((sc->vtscsi_flags & VTSCSI_FLAG_HOTPLUG) == 0 ||
1892 	    sc->vtscsi_event_buf_size < sizeof(struct virtio_scsi_event))
1893 		return;
1894 
1895 	for (i = 0; i < VTSCSI_NUM_EVENT_BUFS; i++) {
1896 		event = &sc->vtscsi_event_bufs[i];
1897 
1898 		error = vtscsi_enqueue_event_buf(sc, event);
1899 		if (error)
1900 			break;
1901 	}
1902 
1903 	KASSERT(i > 0, ("cannot reinit event vq: %d", error));
1904 }
1905 
1906 static void
1907 vtscsi_drain_event_vq(struct vtscsi_softc *sc)
1908 {
1909 	struct virtqueue *vq;
1910 	int last;
1911 
1912 	vq = sc->vtscsi_event_vq;
1913 	last = 0;
1914 
1915 	while (virtqueue_drain(vq, &last) != NULL)
1916 		;
1917 
1918 	KASSERT(virtqueue_empty(vq), ("eventvq not empty"));
1919 }
1920 
1921 static void
1922 vtscsi_complete_vqs_locked(struct vtscsi_softc *sc)
1923 {
1924 
1925 	VTSCSI_LOCK_OWNED(sc);
1926 
1927 	if (sc->vtscsi_request_vq != NULL)
1928 		vtscsi_complete_vq(sc, sc->vtscsi_request_vq);
1929 	if (sc->vtscsi_control_vq != NULL)
1930 		vtscsi_complete_vq(sc, sc->vtscsi_control_vq);
1931 }
1932 
1933 static void
1934 vtscsi_complete_vqs(struct vtscsi_softc *sc)
1935 {
1936 
1937 	VTSCSI_LOCK(sc);
1938 	vtscsi_complete_vqs_locked(sc);
1939 	VTSCSI_UNLOCK(sc);
1940 }
1941 
1942 static void
1943 vtscsi_cancel_request(struct vtscsi_softc *sc, struct vtscsi_request *req)
1944 {
1945 	union ccb *ccb;
1946 	int detach;
1947 
1948 	ccb = req->vsr_ccb;
1949 
1950 	vtscsi_dprintf(sc, VTSCSI_TRACE, "req=%p ccb=%p\n", req, ccb);
1951 
1952 	/*
1953 	 * The callout must be drained when detaching since the request is
1954 	 * about to be freed. The VTSCSI_MTX must not be held for this in
1955 	 * case the callout is pending because there is a deadlock potential.
1956 	 * Otherwise, the virtqueue is being drained because of a bus reset
1957 	 * so we only need to attempt to stop the callouts.
1958 	 */
1959 	detach = (sc->vtscsi_flags & VTSCSI_FLAG_DETACH) != 0;
1960 	if (detach != 0)
1961 		VTSCSI_LOCK_NOTOWNED(sc);
1962 	else
1963 		VTSCSI_LOCK_OWNED(sc);
1964 
1965 	if (req->vsr_flags & VTSCSI_REQ_FLAG_TIMEOUT_SET) {
1966 		if (detach != 0)
1967 			callout_drain(&req->vsr_callout);
1968 		else
1969 			callout_stop(&req->vsr_callout);
1970 	}
1971 
1972 	if (ccb != NULL) {
1973 		if (detach != 0) {
1974 			VTSCSI_LOCK(sc);
1975 			ccb->ccb_h.status = CAM_NO_HBA;
1976 		} else
1977 			ccb->ccb_h.status = CAM_REQUEUE_REQ;
1978 		xpt_done(ccb);
1979 		if (detach != 0)
1980 			VTSCSI_UNLOCK(sc);
1981 	}
1982 
1983 	vtscsi_enqueue_request(sc, req);
1984 }
1985 
1986 static void
1987 vtscsi_drain_vq(struct vtscsi_softc *sc, struct virtqueue *vq)
1988 {
1989 	struct vtscsi_request *req;
1990 	int last;
1991 
1992 	last = 0;
1993 
1994 	vtscsi_dprintf(sc, VTSCSI_TRACE, "vq=%p\n", vq);
1995 
1996 	while ((req = virtqueue_drain(vq, &last)) != NULL)
1997 		vtscsi_cancel_request(sc, req);
1998 
1999 	KASSERT(virtqueue_empty(vq), ("virtqueue not empty"));
2000 }
2001 
2002 static void
2003 vtscsi_drain_vqs(struct vtscsi_softc *sc)
2004 {
2005 
2006 	if (sc->vtscsi_control_vq != NULL)
2007 		vtscsi_drain_vq(sc, sc->vtscsi_control_vq);
2008 	if (sc->vtscsi_request_vq != NULL)
2009 		vtscsi_drain_vq(sc, sc->vtscsi_request_vq);
2010 	if (sc->vtscsi_event_vq != NULL)
2011 		vtscsi_drain_event_vq(sc);
2012 }
2013 
2014 static void
2015 vtscsi_stop(struct vtscsi_softc *sc)
2016 {
2017 
2018 	vtscsi_disable_vqs_intr(sc);
2019 	virtio_stop(sc->vtscsi_dev);
2020 }
2021 
2022 static int
2023 vtscsi_reset_bus(struct vtscsi_softc *sc)
2024 {
2025 	int error;
2026 
2027 	VTSCSI_LOCK_OWNED(sc);
2028 
2029 	if (vtscsi_bus_reset_disable != 0) {
2030 		device_printf(sc->vtscsi_dev, "bus reset disabled\n");
2031 		return (0);
2032 	}
2033 
2034 	sc->vtscsi_flags |= VTSCSI_FLAG_RESET;
2035 
2036 	/*
2037 	 * vtscsi_stop() will cause the in-flight requests to be canceled.
2038 	 * Those requests are then completed here so CAM will retry them
2039 	 * after the reset is complete.
2040 	 */
2041 	vtscsi_stop(sc);
2042 	vtscsi_complete_vqs_locked(sc);
2043 
2044 	/* Rid the virtqueues of any remaining requests. */
2045 	vtscsi_drain_vqs(sc);
2046 
2047 	/*
2048 	 * Any resource shortage that froze the SIMQ cannot persist across
2049 	 * a bus reset so ensure it gets thawed here.
2050 	 */
2051 	if (vtscsi_thaw_simq(sc, VTSCSI_REQUEST | VTSCSI_REQUEST_VQ) != 0)
2052 		xpt_release_simq(sc->vtscsi_sim, 0);
2053 
2054 	error = vtscsi_reinit(sc);
2055 	if (error) {
2056 		device_printf(sc->vtscsi_dev,
2057 		    "reinitialization failed, stopping device...\n");
2058 		vtscsi_stop(sc);
2059 	} else
2060 		vtscsi_announce(sc, AC_BUS_RESET, CAM_TARGET_WILDCARD,
2061 		    CAM_LUN_WILDCARD);
2062 
2063 	sc->vtscsi_flags &= ~VTSCSI_FLAG_RESET;
2064 
2065 	return (error);
2066 }
2067 
2068 static void
2069 vtscsi_init_request(struct vtscsi_softc *sc, struct vtscsi_request *req)
2070 {
2071 
2072 #ifdef INVARIANTS
2073 	int req_nsegs, resp_nsegs;
2074 
2075 	req_nsegs = sglist_count(&req->vsr_ureq, sizeof(req->vsr_ureq));
2076 	resp_nsegs = sglist_count(&req->vsr_uresp, sizeof(req->vsr_uresp));
2077 
2078 	KASSERT(req_nsegs == 1, ("request crossed page boundary"));
2079 	KASSERT(resp_nsegs == 1, ("response crossed page boundary"));
2080 #endif
2081 
2082 	req->vsr_softc = sc;
2083 	callout_init_mtx(&req->vsr_callout, VTSCSI_MTX(sc), 0);
2084 }
2085 
2086 static int
2087 vtscsi_alloc_requests(struct vtscsi_softc *sc)
2088 {
2089 	struct vtscsi_request *req;
2090 	int i, nreqs;
2091 
2092 	/*
2093 	 * Commands destined for either the request or control queues come
2094 	 * from the same SIM queue. Use the size of the request virtqueue
2095 	 * as it (should) be much more frequently used. Some additional
2096 	 * requests are allocated for internal (TMF) use.
2097 	 */
2098 	nreqs = virtqueue_size(sc->vtscsi_request_vq);
2099 	if ((sc->vtscsi_flags & VTSCSI_FLAG_INDIRECT) == 0)
2100 		nreqs /= VTSCSI_MIN_SEGMENTS;
2101 	nreqs += VTSCSI_RESERVED_REQUESTS;
2102 
2103 	for (i = 0; i < nreqs; i++) {
2104 		req = malloc(sizeof(struct vtscsi_request), M_DEVBUF,
2105 		    M_NOWAIT);
2106 		if (req == NULL)
2107 			return (ENOMEM);
2108 
2109 		vtscsi_init_request(sc, req);
2110 
2111 		sc->vtscsi_nrequests++;
2112 		vtscsi_enqueue_request(sc, req);
2113 	}
2114 
2115 	return (0);
2116 }
2117 
2118 static void
2119 vtscsi_free_requests(struct vtscsi_softc *sc)
2120 {
2121 	struct vtscsi_request *req;
2122 
2123 	while ((req = vtscsi_dequeue_request(sc)) != NULL) {
2124 		KASSERT(callout_active(&req->vsr_callout) == 0,
2125 		    ("request callout still active"));
2126 
2127 		sc->vtscsi_nrequests--;
2128 		free(req, M_DEVBUF);
2129 	}
2130 
2131 	KASSERT(sc->vtscsi_nrequests == 0, ("leaked requests: %d",
2132 	    sc->vtscsi_nrequests));
2133 }
2134 
2135 static void
2136 vtscsi_enqueue_request(struct vtscsi_softc *sc, struct vtscsi_request *req)
2137 {
2138 
2139 	KASSERT(req->vsr_softc == sc,
2140 	    ("non-matching request vsr_softc %p/%p", req->vsr_softc, sc));
2141 
2142 	vtscsi_dprintf(sc, VTSCSI_TRACE, "req=%p\n", req);
2143 
2144 	/* A request is available so the SIMQ could be released. */
2145 	if (vtscsi_thaw_simq(sc, VTSCSI_REQUEST) != 0)
2146 		xpt_release_simq(sc->vtscsi_sim, 1);
2147 
2148 	req->vsr_ccb = NULL;
2149 	req->vsr_complete = NULL;
2150 	req->vsr_ptr0 = NULL;
2151 	req->vsr_state = VTSCSI_REQ_STATE_FREE;
2152 	req->vsr_flags = 0;
2153 
2154 	bzero(&req->vsr_ureq, sizeof(req->vsr_ureq));
2155 	bzero(&req->vsr_uresp, sizeof(req->vsr_uresp));
2156 
2157 	/*
2158 	 * We insert at the tail of the queue in order to make it
2159 	 * very unlikely a request will be reused if we race with
2160 	 * stopping its callout handler.
2161 	 */
2162 	TAILQ_INSERT_TAIL(&sc->vtscsi_req_free, req, vsr_link);
2163 }
2164 
2165 static struct vtscsi_request *
2166 vtscsi_dequeue_request(struct vtscsi_softc *sc)
2167 {
2168 	struct vtscsi_request *req;
2169 
2170 	req = TAILQ_FIRST(&sc->vtscsi_req_free);
2171 	if (req != NULL) {
2172 		req->vsr_state = VTSCSI_REQ_STATE_INUSE;
2173 		TAILQ_REMOVE(&sc->vtscsi_req_free, req, vsr_link);
2174 	} else
2175 		sc->vtscsi_stats.dequeue_no_requests++;
2176 
2177 	vtscsi_dprintf(sc, VTSCSI_TRACE, "req=%p\n", req);
2178 
2179 	return (req);
2180 }
2181 
2182 static void
2183 vtscsi_complete_request(struct vtscsi_request *req)
2184 {
2185 
2186 	if (req->vsr_flags & VTSCSI_REQ_FLAG_POLLED)
2187 		req->vsr_flags |= VTSCSI_REQ_FLAG_COMPLETE;
2188 
2189 	if (req->vsr_complete != NULL)
2190 		req->vsr_complete(req->vsr_softc, req);
2191 }
2192 
2193 static void
2194 vtscsi_complete_vq(struct vtscsi_softc *sc, struct virtqueue *vq)
2195 {
2196 	struct vtscsi_request *req;
2197 
2198 	VTSCSI_LOCK_OWNED(sc);
2199 
2200 	while ((req = virtqueue_dequeue(vq, NULL)) != NULL)
2201 		vtscsi_complete_request(req);
2202 }
2203 
2204 static void
2205 vtscsi_control_vq_intr(void *xsc)
2206 {
2207 	struct vtscsi_softc *sc;
2208 	struct virtqueue *vq;
2209 
2210 	sc = xsc;
2211 	vq = sc->vtscsi_control_vq;
2212 
2213 again:
2214 	VTSCSI_LOCK(sc);
2215 
2216 	vtscsi_complete_vq(sc, sc->vtscsi_control_vq);
2217 
2218 	if (virtqueue_enable_intr(vq) != 0) {
2219 		virtqueue_disable_intr(vq);
2220 		VTSCSI_UNLOCK(sc);
2221 		goto again;
2222 	}
2223 
2224 	VTSCSI_UNLOCK(sc);
2225 }
2226 
2227 static void
2228 vtscsi_event_vq_intr(void *xsc)
2229 {
2230 	struct vtscsi_softc *sc;
2231 	struct virtqueue *vq;
2232 	struct virtio_scsi_event *event;
2233 
2234 	sc = xsc;
2235 	vq = sc->vtscsi_event_vq;
2236 
2237 again:
2238 	VTSCSI_LOCK(sc);
2239 
2240 	while ((event = virtqueue_dequeue(vq, NULL)) != NULL)
2241 		vtscsi_handle_event(sc, event);
2242 
2243 	if (virtqueue_enable_intr(vq) != 0) {
2244 		virtqueue_disable_intr(vq);
2245 		VTSCSI_UNLOCK(sc);
2246 		goto again;
2247 	}
2248 
2249 	VTSCSI_UNLOCK(sc);
2250 }
2251 
2252 static void
2253 vtscsi_request_vq_intr(void *xsc)
2254 {
2255 	struct vtscsi_softc *sc;
2256 	struct virtqueue *vq;
2257 
2258 	sc = xsc;
2259 	vq = sc->vtscsi_request_vq;
2260 
2261 again:
2262 	VTSCSI_LOCK(sc);
2263 
2264 	vtscsi_complete_vq(sc, sc->vtscsi_request_vq);
2265 
2266 	if (virtqueue_enable_intr(vq) != 0) {
2267 		virtqueue_disable_intr(vq);
2268 		VTSCSI_UNLOCK(sc);
2269 		goto again;
2270 	}
2271 
2272 	VTSCSI_UNLOCK(sc);
2273 }
2274 
2275 static void
2276 vtscsi_disable_vqs_intr(struct vtscsi_softc *sc)
2277 {
2278 
2279 	virtqueue_disable_intr(sc->vtscsi_control_vq);
2280 	virtqueue_disable_intr(sc->vtscsi_event_vq);
2281 	virtqueue_disable_intr(sc->vtscsi_request_vq);
2282 }
2283 
2284 static void
2285 vtscsi_enable_vqs_intr(struct vtscsi_softc *sc)
2286 {
2287 
2288 	virtqueue_enable_intr(sc->vtscsi_control_vq);
2289 	virtqueue_enable_intr(sc->vtscsi_event_vq);
2290 	virtqueue_enable_intr(sc->vtscsi_request_vq);
2291 }
2292 
2293 static void
2294 vtscsi_get_tunables(struct vtscsi_softc *sc)
2295 {
2296 	char tmpstr[64];
2297 
2298 	TUNABLE_INT_FETCH("hw.vtscsi.debug_level", &sc->vtscsi_debug);
2299 
2300 	snprintf(tmpstr, sizeof(tmpstr), "dev.vtscsi.%d.debug_level",
2301 	    device_get_unit(sc->vtscsi_dev));
2302 	TUNABLE_INT_FETCH(tmpstr, &sc->vtscsi_debug);
2303 }
2304 
2305 static void
2306 vtscsi_setup_sysctl(struct vtscsi_softc *sc)
2307 {
2308 	device_t dev;
2309 	struct vtscsi_statistics *stats;
2310         struct sysctl_ctx_list *ctx;
2311 	struct sysctl_oid *tree;
2312 	struct sysctl_oid_list *child;
2313 
2314 	dev = sc->vtscsi_dev;
2315 	stats = &sc->vtscsi_stats;
2316 	ctx = device_get_sysctl_ctx(dev);
2317 	tree = device_get_sysctl_tree(dev);
2318 	child = SYSCTL_CHILDREN(tree);
2319 
2320 	SYSCTL_ADD_INT(ctx, child, OID_AUTO, "debug_level",
2321 	    CTLFLAG_RW, &sc->vtscsi_debug, 0,
2322 	    "Debug level");
2323 
2324 	SYSCTL_ADD_ULONG(ctx, child, OID_AUTO, "scsi_cmd_timeouts",
2325 	    CTLFLAG_RD, &stats->scsi_cmd_timeouts,
2326 	    "SCSI command timeouts");
2327 	SYSCTL_ADD_ULONG(ctx, child, OID_AUTO, "dequeue_no_requests",
2328 	    CTLFLAG_RD, &stats->dequeue_no_requests,
2329 	    "No available requests to dequeue");
2330 }
2331 
2332 static void
2333 vtscsi_printf_req(struct vtscsi_request *req, const char *func,
2334     const char *fmt, ...)
2335 {
2336 	struct vtscsi_softc *sc;
2337 	union ccb *ccb;
2338 	struct sbuf sb;
2339 	va_list ap;
2340 	char str[192];
2341 	char path_str[64];
2342 
2343 	if (req == NULL)
2344 		return;
2345 
2346 	sc = req->vsr_softc;
2347 	ccb = req->vsr_ccb;
2348 
2349 	va_start(ap, fmt);
2350 	sbuf_new(&sb, str, sizeof(str), 0);
2351 
2352 	if (ccb == NULL) {
2353 		sbuf_printf(&sb, "(noperiph:%s%d:%u): ",
2354 		    cam_sim_name(sc->vtscsi_sim), cam_sim_unit(sc->vtscsi_sim),
2355 		    cam_sim_bus(sc->vtscsi_sim));
2356 	} else {
2357 		xpt_path_string(ccb->ccb_h.path, path_str, sizeof(path_str));
2358 		sbuf_cat(&sb, path_str);
2359 		if (ccb->ccb_h.func_code == XPT_SCSI_IO) {
2360 			scsi_command_string(&ccb->csio, &sb);
2361 			sbuf_printf(&sb, "length %d ", ccb->csio.dxfer_len);
2362 		}
2363 	}
2364 
2365 	sbuf_vprintf(&sb, fmt, ap);
2366 	va_end(ap);
2367 
2368 	sbuf_finish(&sb);
2369 	printf("%s: %s: %s", device_get_nameunit(sc->vtscsi_dev), func,
2370 	    sbuf_data(&sb));
2371 }
2372