xref: /netbsd-src/sys/dev/pci/ld_virtio.c (revision d909946ca08dceb44d7d0f22ec9488679695d976)
1 /*	$NetBSD: ld_virtio.c,v 1.10 2016/07/07 06:55:41 msaitoh Exp $	*/
2 
3 /*
4  * Copyright (c) 2010 Minoura Makoto.
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, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26  */
27 
28 #include <sys/cdefs.h>
29 __KERNEL_RCSID(0, "$NetBSD: ld_virtio.c,v 1.10 2016/07/07 06:55:41 msaitoh Exp $");
30 
31 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/kernel.h>
34 #include <sys/buf.h>
35 #include <sys/bus.h>
36 #include <sys/device.h>
37 #include <sys/disk.h>
38 #include <sys/mutex.h>
39 
40 #include <dev/pci/pcidevs.h>
41 #include <dev/pci/pcireg.h>
42 #include <dev/pci/pcivar.h>
43 
44 #include <dev/ldvar.h>
45 #include <dev/pci/virtioreg.h>
46 #include <dev/pci/virtiovar.h>
47 
48 /*
49  * ld_virtioreg:
50  */
51 /* Configuration registers */
52 #define VIRTIO_BLK_CONFIG_CAPACITY	0 /* 64bit */
53 #define VIRTIO_BLK_CONFIG_SIZE_MAX	8 /* 32bit */
54 #define VIRTIO_BLK_CONFIG_SEG_MAX	12 /* 32bit */
55 #define VIRTIO_BLK_CONFIG_GEOMETRY_C	16 /* 16bit */
56 #define VIRTIO_BLK_CONFIG_GEOMETRY_H	18 /* 8bit */
57 #define VIRTIO_BLK_CONFIG_GEOMETRY_S	19 /* 8bit */
58 #define VIRTIO_BLK_CONFIG_BLK_SIZE	20 /* 32bit */
59 
60 /* Feature bits */
61 #define VIRTIO_BLK_F_BARRIER	(1<<0)
62 #define VIRTIO_BLK_F_SIZE_MAX	(1<<1)
63 #define VIRTIO_BLK_F_SEG_MAX	(1<<2)
64 #define VIRTIO_BLK_F_GEOMETRY	(1<<4)
65 #define VIRTIO_BLK_F_RO		(1<<5)
66 #define VIRTIO_BLK_F_BLK_SIZE	(1<<6)
67 #define VIRTIO_BLK_F_SCSI	(1<<7)
68 #define VIRTIO_BLK_F_FLUSH	(1<<9)
69 
70 /*
71  * Each block request uses at least two segments - one for the header
72  * and one for the status.
73 */
74 #define	VIRTIO_BLK_MIN_SEGMENTS	2
75 
76 #define VIRTIO_BLK_FLAG_BITS \
77 	VIRTIO_COMMON_FLAG_BITS \
78 	"\x0a""FLUSH" \
79 	"\x08""SCSI" \
80 	"\x07""BLK_SIZE" \
81 	"\x06""RO" \
82 	"\x05""GEOMETRY" \
83 	"\x03""SEG_MAX" \
84 	"\x02""SIZE_MAX" \
85 	"\x01""BARRIER"
86 
87 /* Command */
88 #define VIRTIO_BLK_T_IN		0
89 #define VIRTIO_BLK_T_OUT	1
90 #define VIRTIO_BLK_T_BARRIER	0x80000000
91 
92 /* Status */
93 #define VIRTIO_BLK_S_OK		0
94 #define VIRTIO_BLK_S_IOERR	1
95 
96 /* Request header structure */
97 struct virtio_blk_req_hdr {
98 	uint32_t	type;	/* VIRTIO_BLK_T_* */
99 	uint32_t	ioprio;
100 	uint64_t	sector;
101 } __packed;
102 /* 512*virtio_blk_req_hdr.sector byte payload and 1 byte status follows */
103 
104 
105 /*
106  * ld_virtiovar:
107  */
108 struct virtio_blk_req {
109 	struct virtio_blk_req_hdr	vr_hdr;
110 	uint8_t				vr_status;
111 	struct buf			*vr_bp;
112 	bus_dmamap_t			vr_cmdsts;
113 	bus_dmamap_t			vr_payload;
114 };
115 
116 struct ld_virtio_softc {
117 	struct ld_softc		sc_ld;
118 	device_t		sc_dev;
119 
120 	struct virtio_softc	*sc_virtio;
121 	struct virtqueue	sc_vq;
122 
123 	struct virtio_blk_req	*sc_reqs;
124 	bus_dma_segment_t	sc_reqs_seg;
125 
126 	int			sc_readonly;
127 };
128 
129 static int	ld_virtio_match(device_t, cfdata_t, void *);
130 static void	ld_virtio_attach(device_t, device_t, void *);
131 static int	ld_virtio_detach(device_t, int);
132 
133 CFATTACH_DECL_NEW(ld_virtio, sizeof(struct ld_virtio_softc),
134     ld_virtio_match, ld_virtio_attach, ld_virtio_detach, NULL);
135 
136 static int
137 ld_virtio_match(device_t parent, cfdata_t match, void *aux)
138 {
139 	struct virtio_softc *va = aux;
140 
141 	if (va->sc_childdevid == PCI_PRODUCT_VIRTIO_BLOCK)
142 		return 1;
143 
144 	return 0;
145 }
146 
147 static int ld_virtio_vq_done(struct virtqueue *);
148 static int ld_virtio_dump(struct ld_softc *, void *, int, int);
149 static int ld_virtio_start(struct ld_softc *, struct buf *);
150 
151 static int
152 ld_virtio_alloc_reqs(struct ld_virtio_softc *sc, int qsize)
153 {
154 	int allocsize, r, rsegs, i;
155 	struct ld_softc *ld = &sc->sc_ld;
156 	void *vaddr;
157 
158 	allocsize = sizeof(struct virtio_blk_req) * qsize;
159 	r = bus_dmamem_alloc(sc->sc_virtio->sc_dmat, allocsize, 0, 0,
160 			     &sc->sc_reqs_seg, 1, &rsegs, BUS_DMA_NOWAIT);
161 	if (r != 0) {
162 		aprint_error_dev(sc->sc_dev,
163 				 "DMA memory allocation failed, size %d, "
164 				 "error code %d\n", allocsize, r);
165 		goto err_none;
166 	}
167 	r = bus_dmamem_map(sc->sc_virtio->sc_dmat,
168 			   &sc->sc_reqs_seg, 1, allocsize,
169 			   &vaddr, BUS_DMA_NOWAIT);
170 	if (r != 0) {
171 		aprint_error_dev(sc->sc_dev,
172 				 "DMA memory map failed, "
173 				 "error code %d\n", r);
174 		goto err_dmamem_alloc;
175 	}
176 	sc->sc_reqs = vaddr;
177 	memset(vaddr, 0, allocsize);
178 	for (i = 0; i < qsize; i++) {
179 		struct virtio_blk_req *vr = &sc->sc_reqs[i];
180 		r = bus_dmamap_create(sc->sc_virtio->sc_dmat,
181 				      offsetof(struct virtio_blk_req, vr_bp),
182 				      1,
183 				      offsetof(struct virtio_blk_req, vr_bp),
184 				      0,
185 				      BUS_DMA_NOWAIT|BUS_DMA_ALLOCNOW,
186 				      &vr->vr_cmdsts);
187 		if (r != 0) {
188 			aprint_error_dev(sc->sc_dev,
189 					 "command dmamap creation failed, "
190 					 "error code %d\n", r);
191 			goto err_reqs;
192 		}
193 		r = bus_dmamap_load(sc->sc_virtio->sc_dmat, vr->vr_cmdsts,
194 				    &vr->vr_hdr,
195 				    offsetof(struct virtio_blk_req, vr_bp),
196 				    NULL, BUS_DMA_NOWAIT);
197 		if (r != 0) {
198 			aprint_error_dev(sc->sc_dev,
199 					 "command dmamap load failed, "
200 					 "error code %d\n", r);
201 			goto err_reqs;
202 		}
203 		r = bus_dmamap_create(sc->sc_virtio->sc_dmat,
204 				      ld->sc_maxxfer,
205 				      (ld->sc_maxxfer / NBPG) +
206 				      VIRTIO_BLK_MIN_SEGMENTS,
207 				      ld->sc_maxxfer,
208 				      0,
209 				      BUS_DMA_NOWAIT|BUS_DMA_ALLOCNOW,
210 				      &vr->vr_payload);
211 		if (r != 0) {
212 			aprint_error_dev(sc->sc_dev,
213 					 "payload dmamap creation failed, "
214 					 "error code %d\n", r);
215 			goto err_reqs;
216 		}
217 	}
218 	return 0;
219 
220 err_reqs:
221 	for (i = 0; i < qsize; i++) {
222 		struct virtio_blk_req *vr = &sc->sc_reqs[i];
223 		if (vr->vr_cmdsts) {
224 			bus_dmamap_destroy(sc->sc_virtio->sc_dmat,
225 					   vr->vr_cmdsts);
226 			vr->vr_cmdsts = 0;
227 		}
228 		if (vr->vr_payload) {
229 			bus_dmamap_destroy(sc->sc_virtio->sc_dmat,
230 					   vr->vr_payload);
231 			vr->vr_payload = 0;
232 		}
233 	}
234 	bus_dmamem_unmap(sc->sc_virtio->sc_dmat, sc->sc_reqs, allocsize);
235 err_dmamem_alloc:
236 	bus_dmamem_free(sc->sc_virtio->sc_dmat, &sc->sc_reqs_seg, 1);
237 err_none:
238 	return -1;
239 }
240 
241 static void
242 ld_virtio_attach(device_t parent, device_t self, void *aux)
243 {
244 	struct ld_virtio_softc *sc = device_private(self);
245 	struct ld_softc *ld = &sc->sc_ld;
246 	struct virtio_softc *vsc = device_private(parent);
247 	uint32_t features;
248 	char buf[256];
249 	int qsize, maxxfersize, maxnsegs;
250 
251 	if (vsc->sc_child != NULL) {
252 		aprint_normal(": child already attached for %s; "
253 			      "something wrong...\n", device_xname(parent));
254 		return;
255 	}
256 
257 	sc->sc_dev = self;
258 	sc->sc_virtio = vsc;
259 
260 	vsc->sc_child = self;
261 	vsc->sc_ipl = IPL_BIO;
262 	vsc->sc_vqs = &sc->sc_vq;
263 	vsc->sc_nvqs = 1;
264 	vsc->sc_config_change = NULL;
265 	vsc->sc_intrhand = virtio_vq_intr;
266 	vsc->sc_flags = 0;
267 
268 	features = virtio_negotiate_features(vsc,
269 					     (VIRTIO_BLK_F_SIZE_MAX |
270 					      VIRTIO_BLK_F_SEG_MAX |
271 					      VIRTIO_BLK_F_GEOMETRY |
272 					      VIRTIO_BLK_F_RO |
273 					      VIRTIO_BLK_F_BLK_SIZE));
274 	if (features & VIRTIO_BLK_F_RO)
275 		sc->sc_readonly = 1;
276 	else
277 		sc->sc_readonly = 0;
278 
279 	snprintb(buf, sizeof(buf), VIRTIO_BLK_FLAG_BITS, features);
280 	aprint_normal(": Features: %s\n", buf);
281 	aprint_naive("\n");
282 	if (features & VIRTIO_BLK_F_BLK_SIZE) {
283 		ld->sc_secsize = virtio_read_device_config_4(vsc,
284 					VIRTIO_BLK_CONFIG_BLK_SIZE);
285 	} else
286 		ld->sc_secsize = 512;
287 
288 	/* At least genfs_io assumes maxxfer == MAXPHYS. */
289 	if (features & VIRTIO_BLK_F_SIZE_MAX) {
290 		maxxfersize = virtio_read_device_config_4(vsc,
291 		    VIRTIO_BLK_CONFIG_SIZE_MAX);
292 		if (maxxfersize < MAXPHYS) {
293 			aprint_error_dev(sc->sc_dev,
294 			    "Too small SIZE_MAX %dK minimum is %dK\n",
295 			    maxxfersize / 1024, MAXPHYS / 1024);
296 			// goto err;
297 			maxxfersize = MAXPHYS;
298 		} else if (maxxfersize > MAXPHYS) {
299 			aprint_normal_dev(sc->sc_dev,
300 			    "Clip SEG_MAX from %dK to %dK\n",
301 			    maxxfersize / 1024,
302 			    MAXPHYS / 1024);
303 			maxxfersize = MAXPHYS;
304 		}
305 	} else
306 		maxxfersize = MAXPHYS;
307 
308 	if (features & VIRTIO_BLK_F_SEG_MAX) {
309 		maxnsegs = virtio_read_device_config_4(vsc,
310 		    VIRTIO_BLK_CONFIG_SEG_MAX);
311 		if (maxnsegs < VIRTIO_BLK_MIN_SEGMENTS) {
312 			aprint_error_dev(sc->sc_dev,
313 			    "Too small SEG_MAX %d minimum is %d\n",
314 			    maxnsegs, VIRTIO_BLK_MIN_SEGMENTS);
315 			maxnsegs = maxxfersize / NBPG;
316 			// goto err;
317 		}
318 	} else
319 		maxnsegs = maxxfersize / NBPG;
320 
321 	/* 2 for the minimum size */
322 	maxnsegs += VIRTIO_BLK_MIN_SEGMENTS;
323 
324 	if (virtio_alloc_vq(vsc, &sc->sc_vq, 0, maxxfersize, maxnsegs,
325 	    "I/O request") != 0) {
326 		goto err;
327 	}
328 	qsize = sc->sc_vq.vq_num;
329 	sc->sc_vq.vq_done = ld_virtio_vq_done;
330 
331 	ld->sc_dv = self;
332 	ld->sc_secperunit = virtio_read_device_config_8(vsc,
333 				VIRTIO_BLK_CONFIG_CAPACITY);
334 	ld->sc_maxxfer = maxxfersize;
335 	if (features & VIRTIO_BLK_F_GEOMETRY) {
336 		ld->sc_ncylinders = virtio_read_device_config_2(vsc,
337 					VIRTIO_BLK_CONFIG_GEOMETRY_C);
338 		ld->sc_nheads     = virtio_read_device_config_1(vsc,
339 					VIRTIO_BLK_CONFIG_GEOMETRY_H);
340 		ld->sc_nsectors   = virtio_read_device_config_1(vsc,
341 					VIRTIO_BLK_CONFIG_GEOMETRY_S);
342 	}
343 	ld->sc_maxqueuecnt = qsize;
344 
345 	if (ld_virtio_alloc_reqs(sc, qsize) < 0)
346 		goto err;
347 
348 	ld->sc_dump = ld_virtio_dump;
349 	ld->sc_flush = NULL;
350 	ld->sc_start = ld_virtio_start;
351 
352 	ld->sc_flags = LDF_ENABLED;
353 	ldattach(ld);
354 
355 	return;
356 
357 err:
358 	vsc->sc_child = (void*)1;
359 	return;
360 }
361 
362 static int
363 ld_virtio_start(struct ld_softc *ld, struct buf *bp)
364 {
365 	/* splbio */
366 	struct ld_virtio_softc *sc = device_private(ld->sc_dv);
367 	struct virtio_softc *vsc = sc->sc_virtio;
368 	struct virtqueue *vq = &sc->sc_vq;
369 	struct virtio_blk_req *vr;
370 	int r;
371 	int isread = (bp->b_flags & B_READ);
372 	int slot;
373 
374 	if (sc->sc_readonly && !isread)
375 		return EIO;
376 
377 	r = virtio_enqueue_prep(vsc, vq, &slot);
378 	if (r != 0)
379 		return r;
380 
381 	vr = &sc->sc_reqs[slot];
382 	KASSERT(vr->vr_bp == NULL);
383 
384 	r = bus_dmamap_load(vsc->sc_dmat, vr->vr_payload,
385 			    bp->b_data, bp->b_bcount, NULL,
386 			    ((isread?BUS_DMA_READ:BUS_DMA_WRITE)
387 			     |BUS_DMA_NOWAIT));
388 	if (r != 0) {
389 		aprint_error_dev(sc->sc_dev,
390 		    "payload dmamap failed, error code %d\n", r);
391 		virtio_enqueue_abort(vsc, vq, slot);
392 		return r;
393 	}
394 
395 	r = virtio_enqueue_reserve(vsc, vq, slot, vr->vr_payload->dm_nsegs +
396 	    VIRTIO_BLK_MIN_SEGMENTS);
397 	if (r != 0) {
398 		virtio_enqueue_abort(vsc, vq, slot);
399 		bus_dmamap_unload(vsc->sc_dmat, vr->vr_payload);
400 		return r;
401 	}
402 
403 	vr->vr_bp = bp;
404 	vr->vr_hdr.type = isread?VIRTIO_BLK_T_IN:VIRTIO_BLK_T_OUT;
405 	vr->vr_hdr.ioprio = 0;
406 	vr->vr_hdr.sector = bp->b_rawblkno * sc->sc_ld.sc_secsize / 512;
407 
408 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_cmdsts,
409 			0, sizeof(struct virtio_blk_req_hdr),
410 			BUS_DMASYNC_PREWRITE);
411 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_payload,
412 			0, bp->b_bcount,
413 			isread?BUS_DMASYNC_PREREAD:BUS_DMASYNC_PREWRITE);
414 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_cmdsts,
415 			offsetof(struct virtio_blk_req, vr_status),
416 			sizeof(uint8_t),
417 			BUS_DMASYNC_PREREAD);
418 
419 	virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
420 			 0, sizeof(struct virtio_blk_req_hdr),
421 			 true);
422 	virtio_enqueue(vsc, vq, slot, vr->vr_payload, !isread);
423 	virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
424 			 offsetof(struct virtio_blk_req, vr_status),
425 			 sizeof(uint8_t),
426 			 false);
427 	virtio_enqueue_commit(vsc, vq, slot, true);
428 
429 	return 0;
430 }
431 
432 static void
433 ld_virtio_vq_done1(struct ld_virtio_softc *sc, struct virtio_softc *vsc,
434 		   struct virtqueue *vq, int slot)
435 {
436 	struct virtio_blk_req *vr = &sc->sc_reqs[slot];
437 	struct buf *bp = vr->vr_bp;
438 
439 	vr->vr_bp = NULL;
440 
441 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_cmdsts,
442 			0, sizeof(struct virtio_blk_req_hdr),
443 			BUS_DMASYNC_POSTWRITE);
444 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_payload,
445 			0, bp->b_bcount,
446 			(bp->b_flags & B_READ)?BUS_DMASYNC_POSTREAD
447 					      :BUS_DMASYNC_POSTWRITE);
448 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_cmdsts,
449 			sizeof(struct virtio_blk_req_hdr), sizeof(uint8_t),
450 			BUS_DMASYNC_POSTREAD);
451 
452 	if (vr->vr_status != VIRTIO_BLK_S_OK) {
453 		bp->b_error = EIO;
454 		bp->b_resid = bp->b_bcount;
455 	} else {
456 		bp->b_error = 0;
457 		bp->b_resid = 0;
458 	}
459 
460 	virtio_dequeue_commit(vsc, vq, slot);
461 
462 	lddone(&sc->sc_ld, bp);
463 }
464 
465 static int
466 ld_virtio_vq_done(struct virtqueue *vq)
467 {
468 	struct virtio_softc *vsc = vq->vq_owner;
469 	struct ld_virtio_softc *sc = device_private(vsc->sc_child);
470 	int r = 0;
471 	int slot;
472 
473 again:
474 	if (virtio_dequeue(vsc, vq, &slot, NULL))
475 		return r;
476 	r = 1;
477 
478 	ld_virtio_vq_done1(sc, vsc, vq, slot);
479 	goto again;
480 }
481 
482 static int
483 ld_virtio_dump(struct ld_softc *ld, void *data, int blkno, int blkcnt)
484 {
485 	struct ld_virtio_softc *sc = device_private(ld->sc_dv);
486 	struct virtio_softc *vsc = sc->sc_virtio;
487 	struct virtqueue *vq = &sc->sc_vq;
488 	struct virtio_blk_req *vr;
489 	int slot, r;
490 
491 	if (sc->sc_readonly)
492 		return EIO;
493 
494 	r = virtio_enqueue_prep(vsc, vq, &slot);
495 	if (r != 0) {
496 		if (r == EAGAIN) { /* no free slot; dequeue first */
497 			delay(100);
498 			ld_virtio_vq_done(vq);
499 			r = virtio_enqueue_prep(vsc, vq, &slot);
500 			if (r != 0)
501 				return r;
502 		}
503 		return r;
504 	}
505 	vr = &sc->sc_reqs[slot];
506 	r = bus_dmamap_load(vsc->sc_dmat, vr->vr_payload,
507 			    data, blkcnt*ld->sc_secsize, NULL,
508 			    BUS_DMA_WRITE|BUS_DMA_NOWAIT);
509 	if (r != 0)
510 		return r;
511 
512 	r = virtio_enqueue_reserve(vsc, vq, slot, vr->vr_payload->dm_nsegs +
513 	    VIRTIO_BLK_MIN_SEGMENTS);
514 	if (r != 0) {
515 		bus_dmamap_unload(vsc->sc_dmat, vr->vr_payload);
516 		return r;
517 	}
518 
519 	vr->vr_bp = (void*)0xdeadbeef;
520 	vr->vr_hdr.type = VIRTIO_BLK_T_OUT;
521 	vr->vr_hdr.ioprio = 0;
522 	vr->vr_hdr.sector = (daddr_t) blkno * ld->sc_secsize / 512;
523 
524 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_cmdsts,
525 			0, sizeof(struct virtio_blk_req_hdr),
526 			BUS_DMASYNC_PREWRITE);
527 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_payload,
528 			0, blkcnt*ld->sc_secsize,
529 			BUS_DMASYNC_PREWRITE);
530 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_cmdsts,
531 			offsetof(struct virtio_blk_req, vr_status),
532 			sizeof(uint8_t),
533 			BUS_DMASYNC_PREREAD);
534 
535 	virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
536 			 0, sizeof(struct virtio_blk_req_hdr),
537 			 true);
538 	virtio_enqueue(vsc, vq, slot, vr->vr_payload, true);
539 	virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
540 			 offsetof(struct virtio_blk_req, vr_status),
541 			 sizeof(uint8_t),
542 			 false);
543 	virtio_enqueue_commit(vsc, vq, slot, true);
544 
545 	for ( ; ; ) {
546 		int dslot;
547 
548 		r = virtio_dequeue(vsc, vq, &dslot, NULL);
549 		if (r != 0)
550 			continue;
551 		if (dslot != slot) {
552 			ld_virtio_vq_done1(sc, vsc, vq, dslot);
553 			continue;
554 		} else
555 			break;
556 	}
557 
558 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_cmdsts,
559 			0, sizeof(struct virtio_blk_req_hdr),
560 			BUS_DMASYNC_POSTWRITE);
561 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_payload,
562 			0, blkcnt*ld->sc_secsize,
563 			BUS_DMASYNC_POSTWRITE);
564 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_cmdsts,
565 			offsetof(struct virtio_blk_req, vr_status),
566 			sizeof(uint8_t),
567 			BUS_DMASYNC_POSTREAD);
568 	if (vr->vr_status == VIRTIO_BLK_S_OK)
569 		r = 0;
570 	else
571 		r = EIO;
572 	virtio_dequeue_commit(vsc, vq, slot);
573 
574 	return r;
575 }
576 
577 static int
578 ld_virtio_detach(device_t self, int flags)
579 {
580 	struct ld_virtio_softc *sc = device_private(self);
581 	struct ld_softc *ld = &sc->sc_ld;
582 	bus_dma_tag_t dmat = sc->sc_virtio->sc_dmat;
583 	int r, i, qsize;
584 
585 	qsize = sc->sc_vq.vq_num;
586 	r = ldbegindetach(ld, flags);
587 	if (r != 0)
588 		return r;
589 	virtio_reset(sc->sc_virtio);
590 	virtio_free_vq(sc->sc_virtio, &sc->sc_vq);
591 
592 	for (i = 0; i < qsize; i++) {
593 		bus_dmamap_destroy(dmat,
594 				   sc->sc_reqs[i].vr_cmdsts);
595 		bus_dmamap_destroy(dmat,
596 				   sc->sc_reqs[i].vr_payload);
597 	}
598 	bus_dmamem_unmap(dmat, sc->sc_reqs,
599 			 sizeof(struct virtio_blk_req) * qsize);
600 	bus_dmamem_free(dmat, &sc->sc_reqs_seg, 1);
601 
602 	ldenddetach(ld);
603 
604 	return 0;
605 }
606