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ld_virtio.c revision 1.8
      1 /*	$NetBSD: ld_virtio.c,v 1.8 2015/05/05 10:56:13 ozaki-r 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 1.8 2015/05/05 10:56:13 ozaki-r 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 /* Command */
     71 #define VIRTIO_BLK_T_IN		0
     72 #define VIRTIO_BLK_T_OUT	1
     73 #define VIRTIO_BLK_T_BARRIER	0x80000000
     74 
     75 /* Status */
     76 #define VIRTIO_BLK_S_OK		0
     77 #define VIRTIO_BLK_S_IOERR	1
     78 
     79 /* Request header structure */
     80 struct virtio_blk_req_hdr {
     81 	uint32_t	type;	/* VIRTIO_BLK_T_* */
     82 	uint32_t	ioprio;
     83 	uint64_t	sector;
     84 } __packed;
     85 /* 512*virtio_blk_req_hdr.sector byte payload and 1 byte status follows */
     86 
     87 
     88 /*
     89  * ld_virtiovar:
     90  */
     91 struct virtio_blk_req {
     92 	struct virtio_blk_req_hdr	vr_hdr;
     93 	uint8_t				vr_status;
     94 	struct buf			*vr_bp;
     95 	bus_dmamap_t			vr_cmdsts;
     96 	bus_dmamap_t			vr_payload;
     97 };
     98 
     99 struct ld_virtio_softc {
    100 	struct ld_softc		sc_ld;
    101 	device_t		sc_dev;
    102 
    103 	struct virtio_softc	*sc_virtio;
    104 	struct virtqueue	sc_vq[1];
    105 
    106 	struct virtio_blk_req	*sc_reqs;
    107 	bus_dma_segment_t	sc_reqs_segs[1];
    108 
    109 	kmutex_t		sc_lock;
    110 
    111 	int			sc_readonly;
    112 };
    113 
    114 static int	ld_virtio_match(device_t, cfdata_t, void *);
    115 static void	ld_virtio_attach(device_t, device_t, void *);
    116 static int	ld_virtio_detach(device_t, int);
    117 
    118 CFATTACH_DECL_NEW(ld_virtio, sizeof(struct ld_virtio_softc),
    119     ld_virtio_match, ld_virtio_attach, ld_virtio_detach, NULL);
    120 
    121 static int
    122 ld_virtio_match(device_t parent, cfdata_t match, void *aux)
    123 {
    124 	struct virtio_softc *va = aux;
    125 
    126 	if (va->sc_childdevid == PCI_PRODUCT_VIRTIO_BLOCK)
    127 		return 1;
    128 
    129 	return 0;
    130 }
    131 
    132 static int ld_virtio_vq_done(struct virtqueue *);
    133 static int ld_virtio_dump(struct ld_softc *, void *, int, int);
    134 static int ld_virtio_start(struct ld_softc *, struct buf *);
    135 
    136 static int
    137 ld_virtio_alloc_reqs(struct ld_virtio_softc *sc, int qsize)
    138 {
    139 	int allocsize, r, rsegs, i;
    140 	struct ld_softc *ld = &sc->sc_ld;
    141 	void *vaddr;
    142 
    143 	allocsize = sizeof(struct virtio_blk_req) * qsize;
    144 	r = bus_dmamem_alloc(sc->sc_virtio->sc_dmat, allocsize, 0, 0,
    145 			     &sc->sc_reqs_segs[0], 1, &rsegs, BUS_DMA_NOWAIT);
    146 	if (r != 0) {
    147 		aprint_error_dev(sc->sc_dev,
    148 				 "DMA memory allocation failed, size %d, "
    149 				 "error code %d\n", allocsize, r);
    150 		goto err_none;
    151 	}
    152 	r = bus_dmamem_map(sc->sc_virtio->sc_dmat,
    153 			   &sc->sc_reqs_segs[0], 1, allocsize,
    154 			   &vaddr, BUS_DMA_NOWAIT);
    155 	if (r != 0) {
    156 		aprint_error_dev(sc->sc_dev,
    157 				 "DMA memory map failed, "
    158 				 "error code %d\n", r);
    159 		goto err_dmamem_alloc;
    160 	}
    161 	sc->sc_reqs = vaddr;
    162 	memset(vaddr, 0, allocsize);
    163 	for (i = 0; i < qsize; i++) {
    164 		struct virtio_blk_req *vr = &sc->sc_reqs[i];
    165 		r = bus_dmamap_create(sc->sc_virtio->sc_dmat,
    166 				      offsetof(struct virtio_blk_req, vr_bp),
    167 				      1,
    168 				      offsetof(struct virtio_blk_req, vr_bp),
    169 				      0,
    170 				      BUS_DMA_NOWAIT|BUS_DMA_ALLOCNOW,
    171 				      &vr->vr_cmdsts);
    172 		if (r != 0) {
    173 			aprint_error_dev(sc->sc_dev,
    174 					 "command dmamap creation failed, "
    175 					 "error code %d\n", r);
    176 			goto err_reqs;
    177 		}
    178 		r = bus_dmamap_load(sc->sc_virtio->sc_dmat, vr->vr_cmdsts,
    179 				    &vr->vr_hdr,
    180 				    offsetof(struct virtio_blk_req, vr_bp),
    181 				    NULL, BUS_DMA_NOWAIT);
    182 		if (r != 0) {
    183 			aprint_error_dev(sc->sc_dev,
    184 					 "command dmamap load failed, "
    185 					 "error code %d\n", r);
    186 			goto err_reqs;
    187 		}
    188 		r = bus_dmamap_create(sc->sc_virtio->sc_dmat,
    189 				      ld->sc_maxxfer,
    190 				      (ld->sc_maxxfer / NBPG) + 2,
    191 				      ld->sc_maxxfer,
    192 				      0,
    193 				      BUS_DMA_NOWAIT|BUS_DMA_ALLOCNOW,
    194 				      &vr->vr_payload);
    195 		if (r != 0) {
    196 			aprint_error_dev(sc->sc_dev,
    197 					 "payload dmamap creation failed, "
    198 					 "error code %d\n", r);
    199 			goto err_reqs;
    200 		}
    201 	}
    202 	return 0;
    203 
    204 err_reqs:
    205 	for (i = 0; i < qsize; i++) {
    206 		struct virtio_blk_req *vr = &sc->sc_reqs[i];
    207 		if (vr->vr_cmdsts) {
    208 			bus_dmamap_destroy(sc->sc_virtio->sc_dmat,
    209 					   vr->vr_cmdsts);
    210 			vr->vr_cmdsts = 0;
    211 		}
    212 		if (vr->vr_payload) {
    213 			bus_dmamap_destroy(sc->sc_virtio->sc_dmat,
    214 					   vr->vr_payload);
    215 			vr->vr_payload = 0;
    216 		}
    217 	}
    218 	bus_dmamem_unmap(sc->sc_virtio->sc_dmat, sc->sc_reqs, allocsize);
    219 err_dmamem_alloc:
    220 	bus_dmamem_free(sc->sc_virtio->sc_dmat, &sc->sc_reqs_segs[0], 1);
    221 err_none:
    222 	return -1;
    223 }
    224 
    225 static void
    226 ld_virtio_attach(device_t parent, device_t self, void *aux)
    227 {
    228 	struct ld_virtio_softc *sc = device_private(self);
    229 	struct ld_softc *ld = &sc->sc_ld;
    230 	struct virtio_softc *vsc = device_private(parent);
    231 	uint32_t features;
    232 	int qsize, maxxfersize;
    233 
    234 	if (vsc->sc_child != NULL) {
    235 		aprint_normal(": child already attached for %s; "
    236 			      "something wrong...\n",
    237 			      device_xname(parent));
    238 		return;
    239 	}
    240 	aprint_normal("\n");
    241 	aprint_naive("\n");
    242 
    243 	sc->sc_dev = self;
    244 	sc->sc_virtio = vsc;
    245 
    246 	vsc->sc_child = self;
    247 	vsc->sc_ipl = IPL_BIO;
    248 	vsc->sc_vqs = &sc->sc_vq[0];
    249 	vsc->sc_nvqs = 1;
    250 	vsc->sc_config_change = NULL;
    251 	vsc->sc_intrhand = virtio_vq_intr;
    252 	vsc->sc_flags = 0;
    253 
    254 	features = virtio_negotiate_features(vsc,
    255 					     (VIRTIO_BLK_F_SIZE_MAX |
    256 					      VIRTIO_BLK_F_SEG_MAX |
    257 					      VIRTIO_BLK_F_GEOMETRY |
    258 					      VIRTIO_BLK_F_RO |
    259 					      VIRTIO_BLK_F_BLK_SIZE));
    260 	if (features & VIRTIO_BLK_F_RO)
    261 		sc->sc_readonly = 1;
    262 	else
    263 		sc->sc_readonly = 0;
    264 
    265 	ld->sc_secsize = 512;
    266 	if (features & VIRTIO_BLK_F_BLK_SIZE) {
    267 		ld->sc_secsize = virtio_read_device_config_4(vsc,
    268 					VIRTIO_BLK_CONFIG_BLK_SIZE);
    269 	}
    270 	maxxfersize = MAXPHYS;
    271 #if 0	/* At least genfs_io assumes maxxfer == MAXPHYS. */
    272 	if (features & VIRTIO_BLK_F_SEG_MAX) {
    273 		maxxfersize = virtio_read_device_config_4(vsc,
    274 					VIRTIO_BLK_CONFIG_SEG_MAX)
    275 				* ld->sc_secsize;
    276 		if (maxxfersize > MAXPHYS)
    277 			maxxfersize = MAXPHYS;
    278 	}
    279 #endif
    280 
    281 	if (virtio_alloc_vq(vsc, &sc->sc_vq[0], 0,
    282 			    maxxfersize, maxxfersize / NBPG + 2,
    283 			    "I/O request") != 0) {
    284 		goto err;
    285 	}
    286 	qsize = sc->sc_vq[0].vq_num;
    287 	sc->sc_vq[0].vq_done = ld_virtio_vq_done;
    288 
    289 	ld->sc_dv = self;
    290 	ld->sc_secperunit = virtio_read_device_config_8(vsc,
    291 				VIRTIO_BLK_CONFIG_CAPACITY);
    292 	ld->sc_maxxfer = maxxfersize;
    293 	if (features & VIRTIO_BLK_F_GEOMETRY) {
    294 		ld->sc_ncylinders = virtio_read_device_config_2(vsc,
    295 					VIRTIO_BLK_CONFIG_GEOMETRY_C);
    296 		ld->sc_nheads     = virtio_read_device_config_1(vsc,
    297 					VIRTIO_BLK_CONFIG_GEOMETRY_H);
    298 		ld->sc_nsectors   = virtio_read_device_config_1(vsc,
    299 					VIRTIO_BLK_CONFIG_GEOMETRY_S);
    300 	}
    301 	ld->sc_maxqueuecnt = qsize;
    302 
    303 	if (ld_virtio_alloc_reqs(sc, qsize) < 0)
    304 		goto err;
    305 
    306 	mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_BIO);
    307 
    308 	ld->sc_dump = ld_virtio_dump;
    309 	ld->sc_flush = NULL;
    310 	ld->sc_start = ld_virtio_start;
    311 
    312 	ld->sc_flags = LDF_ENABLED;
    313 	ldattach(ld);
    314 
    315 	return;
    316 
    317 err:
    318 	vsc->sc_child = (void*)1;
    319 	return;
    320 }
    321 
    322 static int
    323 ld_virtio_start(struct ld_softc *ld, struct buf *bp)
    324 {
    325 	/* splbio */
    326 	struct ld_virtio_softc *sc = device_private(ld->sc_dv);
    327 	struct virtio_softc *vsc = sc->sc_virtio;
    328 	struct virtqueue *vq = &sc->sc_vq[0];
    329 	struct virtio_blk_req *vr;
    330 	int r;
    331 	int isread = (bp->b_flags & B_READ);
    332 	int slot;
    333 
    334 	if (sc->sc_readonly && !isread)
    335 		return EIO;
    336 
    337 	r = virtio_enqueue_prep(vsc, vq, &slot);
    338 	if (r != 0)
    339 		return r;
    340 	vr = &sc->sc_reqs[slot];
    341 	r = bus_dmamap_load(vsc->sc_dmat, vr->vr_payload,
    342 			    bp->b_data, bp->b_bcount, NULL,
    343 			    ((isread?BUS_DMA_READ:BUS_DMA_WRITE)
    344 			     |BUS_DMA_NOWAIT));
    345 	if (r != 0)
    346 		return r;
    347 
    348 	r = virtio_enqueue_reserve(vsc, vq, slot, vr->vr_payload->dm_nsegs + 2);
    349 	if (r != 0) {
    350 		bus_dmamap_unload(vsc->sc_dmat, vr->vr_payload);
    351 		return r;
    352 	}
    353 
    354 	vr->vr_bp = bp;
    355 	vr->vr_hdr.type = isread?VIRTIO_BLK_T_IN:VIRTIO_BLK_T_OUT;
    356 	vr->vr_hdr.ioprio = 0;
    357 	vr->vr_hdr.sector = bp->b_rawblkno * sc->sc_ld.sc_secsize / 512;
    358 
    359 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_cmdsts,
    360 			0, sizeof(struct virtio_blk_req_hdr),
    361 			BUS_DMASYNC_PREWRITE);
    362 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_payload,
    363 			0, bp->b_bcount,
    364 			isread?BUS_DMASYNC_PREREAD:BUS_DMASYNC_PREWRITE);
    365 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_cmdsts,
    366 			offsetof(struct virtio_blk_req, vr_status),
    367 			sizeof(uint8_t),
    368 			BUS_DMASYNC_PREREAD);
    369 
    370 	virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
    371 			 0, sizeof(struct virtio_blk_req_hdr),
    372 			 true);
    373 	virtio_enqueue(vsc, vq, slot, vr->vr_payload, !isread);
    374 	virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
    375 			 offsetof(struct virtio_blk_req, vr_status),
    376 			 sizeof(uint8_t),
    377 			 false);
    378 	virtio_enqueue_commit(vsc, vq, slot, true);
    379 
    380 	return 0;
    381 }
    382 
    383 static void
    384 ld_virtio_vq_done1(struct ld_virtio_softc *sc, struct virtio_softc *vsc,
    385 		   struct virtqueue *vq, int slot)
    386 {
    387 	struct virtio_blk_req *vr = &sc->sc_reqs[slot];
    388 	struct buf *bp = vr->vr_bp;
    389 
    390 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_cmdsts,
    391 			0, sizeof(struct virtio_blk_req_hdr),
    392 			BUS_DMASYNC_POSTWRITE);
    393 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_payload,
    394 			0, bp->b_bcount,
    395 			(bp->b_flags & B_READ)?BUS_DMASYNC_POSTREAD
    396 					      :BUS_DMASYNC_POSTWRITE);
    397 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_cmdsts,
    398 			sizeof(struct virtio_blk_req_hdr), sizeof(uint8_t),
    399 			BUS_DMASYNC_POSTREAD);
    400 
    401 	if (vr->vr_status != VIRTIO_BLK_S_OK) {
    402 		bp->b_error = EIO;
    403 		bp->b_resid = bp->b_bcount;
    404 	} else {
    405 		bp->b_error = 0;
    406 		bp->b_resid = 0;
    407 	}
    408 
    409 	virtio_dequeue_commit(vsc, vq, slot);
    410 
    411 	lddone(&sc->sc_ld, bp);
    412 }
    413 
    414 static int
    415 ld_virtio_vq_done(struct virtqueue *vq)
    416 {
    417 	struct virtio_softc *vsc = vq->vq_owner;
    418 	struct ld_virtio_softc *sc = device_private(vsc->sc_child);
    419 	int r = 0;
    420 	int slot;
    421 
    422 again:
    423 	if (virtio_dequeue(vsc, vq, &slot, NULL))
    424 		return r;
    425 	r = 1;
    426 
    427 	ld_virtio_vq_done1(sc, vsc, vq, slot);
    428 	goto again;
    429 }
    430 
    431 static int
    432 ld_virtio_dump(struct ld_softc *ld, void *data, int blkno, int blkcnt)
    433 {
    434 	struct ld_virtio_softc *sc = device_private(ld->sc_dv);
    435 	struct virtio_softc *vsc = sc->sc_virtio;
    436 	struct virtqueue *vq = &sc->sc_vq[0];
    437 	struct virtio_blk_req *vr;
    438 	int slot, r;
    439 
    440 	if (sc->sc_readonly)
    441 		return EIO;
    442 
    443 	r = virtio_enqueue_prep(vsc, vq, &slot);
    444 	if (r != 0) {
    445 		if (r == EAGAIN) { /* no free slot; dequeue first */
    446 			delay(100);
    447 			ld_virtio_vq_done(vq);
    448 			r = virtio_enqueue_prep(vsc, vq, &slot);
    449 			if (r != 0)
    450 				return r;
    451 		}
    452 		return r;
    453 	}
    454 	vr = &sc->sc_reqs[slot];
    455 	r = bus_dmamap_load(vsc->sc_dmat, vr->vr_payload,
    456 			    data, blkcnt*ld->sc_secsize, NULL,
    457 			    BUS_DMA_WRITE|BUS_DMA_NOWAIT);
    458 	if (r != 0)
    459 		return r;
    460 
    461 	r = virtio_enqueue_reserve(vsc, vq, slot, vr->vr_payload->dm_nsegs + 2);
    462 	if (r != 0) {
    463 		bus_dmamap_unload(vsc->sc_dmat, vr->vr_payload);
    464 		return r;
    465 	}
    466 
    467 	vr->vr_bp = (void*)0xdeadbeef;
    468 	vr->vr_hdr.type = VIRTIO_BLK_T_OUT;
    469 	vr->vr_hdr.ioprio = 0;
    470 	vr->vr_hdr.sector = (daddr_t) blkno * ld->sc_secsize / 512;
    471 
    472 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_cmdsts,
    473 			0, sizeof(struct virtio_blk_req_hdr),
    474 			BUS_DMASYNC_PREWRITE);
    475 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_payload,
    476 			0, blkcnt*ld->sc_secsize,
    477 			BUS_DMASYNC_PREWRITE);
    478 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_cmdsts,
    479 			offsetof(struct virtio_blk_req, vr_status),
    480 			sizeof(uint8_t),
    481 			BUS_DMASYNC_PREREAD);
    482 
    483 	virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
    484 			 0, sizeof(struct virtio_blk_req_hdr),
    485 			 true);
    486 	virtio_enqueue(vsc, vq, slot, vr->vr_payload, true);
    487 	virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
    488 			 offsetof(struct virtio_blk_req, vr_status),
    489 			 sizeof(uint8_t),
    490 			 false);
    491 	virtio_enqueue_commit(vsc, vq, slot, true);
    492 
    493 	for ( ; ; ) {
    494 		int dslot;
    495 
    496 		r = virtio_dequeue(vsc, vq, &dslot, NULL);
    497 		if (r != 0)
    498 			continue;
    499 		if (dslot != slot) {
    500 			ld_virtio_vq_done1(sc, vsc, vq, dslot);
    501 			continue;
    502 		} else
    503 			break;
    504 	}
    505 
    506 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_cmdsts,
    507 			0, sizeof(struct virtio_blk_req_hdr),
    508 			BUS_DMASYNC_POSTWRITE);
    509 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_payload,
    510 			0, blkcnt*ld->sc_secsize,
    511 			BUS_DMASYNC_POSTWRITE);
    512 	bus_dmamap_sync(vsc->sc_dmat, vr->vr_cmdsts,
    513 			offsetof(struct virtio_blk_req, vr_status),
    514 			sizeof(uint8_t),
    515 			BUS_DMASYNC_POSTREAD);
    516 	if (vr->vr_status == VIRTIO_BLK_S_OK)
    517 		r = 0;
    518 	else
    519 		r = EIO;
    520 	virtio_dequeue_commit(vsc, vq, slot);
    521 
    522 	return r;
    523 }
    524 
    525 static int
    526 ld_virtio_detach(device_t self, int flags)
    527 {
    528 	struct ld_virtio_softc *sc = device_private(self);
    529 	struct ld_softc *ld = &sc->sc_ld;
    530 	bus_dma_tag_t dmat = sc->sc_virtio->sc_dmat;
    531 	int r, i, qsize;
    532 
    533 	qsize = sc->sc_vq[0].vq_num;
    534 	r = ldbegindetach(ld, flags);
    535 	if (r != 0)
    536 		return r;
    537 	virtio_reset(sc->sc_virtio);
    538 	virtio_free_vq(sc->sc_virtio, &sc->sc_vq[0]);
    539 
    540 	for (i = 0; i < qsize; i++) {
    541 		bus_dmamap_destroy(dmat,
    542 				   sc->sc_reqs[i].vr_cmdsts);
    543 		bus_dmamap_destroy(dmat,
    544 				   sc->sc_reqs[i].vr_payload);
    545 	}
    546 	bus_dmamem_unmap(dmat, sc->sc_reqs,
    547 			 sizeof(struct virtio_blk_req) * qsize);
    548 	bus_dmamem_free(dmat, &sc->sc_reqs_segs[0], 1);
    549 
    550 	ldenddetach(ld);
    551 
    552 	return 0;
    553 }
    554