Home | History | Annotate | Line # | Download | only in pci
      1 /*	$NetBSD: ld_virtio.c,v 1.45 2025/08/27 04:41:24 isaki 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 1.45 2025/08/27 04:41:24 isaki 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/bufq.h>
     36 #include <sys/bus.h>
     37 #include <sys/device.h>
     38 #include <sys/disk.h>
     39 #include <sys/mutex.h>
     40 #include <sys/module.h>
     41 #include <sys/kmem.h>
     42 
     43 #include <dev/ldvar.h>
     44 #include <dev/pci/virtioreg.h>
     45 #include <dev/pci/virtiovar.h>
     46 
     47 #include "ioconf.h"
     48 
     49 /*
     50  * ld_virtioreg:
     51  */
     52 /* Configuration registers */
     53 #define VIRTIO_BLK_CONFIG_CAPACITY	0 /* 64bit */
     54 #define VIRTIO_BLK_CONFIG_SIZE_MAX	8 /* 32bit */
     55 #define VIRTIO_BLK_CONFIG_SEG_MAX	12 /* 32bit */
     56 #define VIRTIO_BLK_CONFIG_GEOMETRY_C	16 /* 16bit */
     57 #define VIRTIO_BLK_CONFIG_GEOMETRY_H	18 /* 8bit */
     58 #define VIRTIO_BLK_CONFIG_GEOMETRY_S	19 /* 8bit */
     59 #define VIRTIO_BLK_CONFIG_BLK_SIZE	20 /* 32bit */
     60 #define VIRTIO_BLK_CONFIG_PHYSICAL_BLOCK_EXP		24 /* 8bit */
     61 #define VIRTIO_BLK_CONFIG_ALIGNMENT_OFFSET		25 /* 8bit */
     62 #define VIRTIO_BLK_CONFIG_MIN_IO_SIZE			26 /* 16bit */
     63 #define VIRTIO_BLK_CONFIG_OPT_IO_SIZE			28 /* 32bit */
     64 #define VIRTIO_BLK_CONFIG_WRITEBACK	32 /* 8bit */
     65 #define VIRTIO_BLK_CONFIG_NUM_QUEUES			34 /* 16bit */
     66 #define VIRTIO_BLK_CONFIG_MAX_DISCARD_SECTORS		36 /* 32bit */
     67 #define VIRTIO_BLK_CONFIG_MAX_DISCARD_SEG		40 /* 32bit */
     68 #define VIRTIO_BLK_CONFIG_DISCARD_SECTOR_ALIGNMENT	44 /* 32bit */
     69 
     70 /* Feature bits */
     71 #define VIRTIO_BLK_F_BARRIER	(1<<0)
     72 #define VIRTIO_BLK_F_SIZE_MAX	(1<<1)
     73 #define VIRTIO_BLK_F_SEG_MAX	(1<<2)
     74 #define VIRTIO_BLK_F_GEOMETRY	(1<<4)
     75 #define VIRTIO_BLK_F_RO		(1<<5)
     76 #define VIRTIO_BLK_F_BLK_SIZE	(1<<6)
     77 #define VIRTIO_BLK_F_SCSI	(1<<7)
     78 #define VIRTIO_BLK_F_FLUSH	(1<<9)
     79 #define VIRTIO_BLK_F_TOPOLOGY	(1<<10)
     80 #define VIRTIO_BLK_F_CONFIG_WCE	(1<<11)
     81 #define VIRTIO_BLK_F_MQ			(1<<12)
     82 #define VIRTIO_BLK_F_DISCARD		(1<<13)
     83 #define VIRTIO_BLK_F_WRITE_ZEROES	(1<<14)
     84 #define VIRTIO_BLK_F_LIFETIME		(1<<15)
     85 #define VIRTIO_BLK_F_SECURE_ERASE	(1<<16)
     86 
     87 /*
     88  * Each block request uses at least two segments - one for the header
     89  * and one for the status.
     90 */
     91 #define	VIRTIO_BLK_CTRL_SEGMENTS	2
     92 
     93 #define VIRTIO_BLK_FLAG_BITS			\
     94 	VIRTIO_COMMON_FLAG_BITS			\
     95 	"b\x10" "SECURE_ERASE\0"		\
     96 	"b\x0f" "LIFETIME\0"			\
     97 	"b\x0e" "WRITE_ZEROES\0"		\
     98 	"b\x0d" "DISCARD\0"			\
     99 	"b\x0c" "MQ\0"				\
    100 	"b\x0b" "CONFIG_WCE\0"			\
    101 	"b\x0a" "TOPOLOGY\0"			\
    102 	"b\x09" "FLUSH\0"			\
    103 	"b\x07" "SCSI\0"			\
    104 	"b\x06" "BLK_SIZE\0"			\
    105 	"b\x05" "RO\0"				\
    106 	"b\x04" "GEOMETRY\0"			\
    107 	"b\x02" "SEG_MAX\0"			\
    108 	"b\x01" "SIZE_MAX\0"			\
    109 	"b\x00" "BARRIER\0"
    110 
    111 /* Command */
    112 #define VIRTIO_BLK_T_IN		0
    113 #define VIRTIO_BLK_T_OUT	1
    114 #define VIRTIO_BLK_T_FLUSH	4
    115 #define VIRTIO_BLK_T_GET_ID		8
    116 #define VIRTIO_BLK_T_GET_LIFETIME	10
    117 #define VIRTIO_BLK_T_DISCARD		11
    118 #define VIRTIO_BLK_T_WRITE_ZEROES	13
    119 #define VIRTIO_BLK_T_SECURE_ERASE	14
    120 #define VIRTIO_BLK_T_BARRIER	0x80000000
    121 
    122 /* Sector */
    123 #define VIRTIO_BLK_BSIZE	512
    124 
    125 /* Status */
    126 #define VIRTIO_BLK_S_OK		0
    127 #define VIRTIO_BLK_S_IOERR	1
    128 #define VIRTIO_BLK_S_UNSUPP	2
    129 
    130 /* Request header structure */
    131 struct virtio_blk_req_hdr {
    132 	uint32_t	type;	/* VIRTIO_BLK_T_* */
    133 	uint32_t	ioprio;
    134 	uint64_t	sector;
    135 } __packed;
    136 /* payload and 1 byte status follows */
    137 
    138 struct virtio_blk_discard_write_zeroes {
    139 	uint64_t	sector;
    140 	uint32_t	num_sectors;
    141 	union {
    142 		uint32_t	flags;
    143 		struct {
    144 			uint32_t	unmap:1;
    145 			uint32_t	reserved:31;
    146 		};
    147 	};
    148 } __packed;
    149 
    150 /*
    151  * ld_virtiovar:
    152  */
    153 struct virtio_blk_req {
    154 	struct virtio_blk_req_hdr	vr_hdr;
    155 	uint8_t				vr_status;
    156 	struct buf			*vr_bp;
    157 #define DUMMY_VR_BP				((void *)1)
    158 	bus_dmamap_t			vr_cmdsts;
    159 	bus_dmamap_t			vr_payload;
    160 	void *				vr_datap;
    161 	size_t				vr_datas;
    162 };
    163 
    164 struct ld_virtio_softc {
    165 	struct ld_softc		sc_ld;
    166 	device_t		sc_dev;
    167 
    168 	uint32_t		sc_seg_max; /* max number of segs in xfer */
    169 	uint32_t		sc_size_max; /* max size of single seg */
    170 
    171 	struct virtio_softc	*sc_virtio;
    172 	struct virtqueue	sc_vq;
    173 
    174 	struct virtio_blk_req	*sc_reqs;
    175 	bus_dma_segment_t	sc_reqs_seg;
    176 
    177 	int			sc_readonly;
    178 
    179 	enum {
    180 		SYNC_FREE, SYNC_BUSY, SYNC_DONE
    181 	}			sc_sync_use;
    182 	kcondvar_t		sc_sync_wait;
    183 	kmutex_t		sc_sync_wait_lock;
    184 	uint8_t			sc_sync_status;
    185 	uint8_t			*sc_typename;
    186 
    187 	uint32_t		sc_max_discard_sectors;
    188 	uint32_t		sc_max_discard_seg;
    189 #if 0
    190 	uint32_t		sc_discard_sector_alignment;
    191 #endif
    192 };
    193 
    194 static int	ld_virtio_match(device_t, cfdata_t, void *);
    195 static void	ld_virtio_attach(device_t, device_t, void *);
    196 static int	ld_virtio_detach(device_t, int);
    197 
    198 CFATTACH_DECL_NEW(ld_virtio, sizeof(struct ld_virtio_softc),
    199     ld_virtio_match, ld_virtio_attach, ld_virtio_detach, NULL);
    200 
    201 static int
    202 ld_virtio_match(device_t parent, cfdata_t match, void *aux)
    203 {
    204 	struct virtio_attach_args *va = aux;
    205 
    206 	if (va->sc_childdevid == VIRTIO_DEVICE_ID_BLOCK)
    207 		return 1;
    208 
    209 	return 0;
    210 }
    211 
    212 static int ld_virtio_vq_done(struct virtqueue *);
    213 static int ld_virtio_dump(struct ld_softc *, void *, daddr_t, int);
    214 static int ld_virtio_start(struct ld_softc *, struct buf *);
    215 static int ld_virtio_ioctl(struct ld_softc *, u_long, void *, int32_t, bool);
    216 static int ld_virtio_info(struct ld_softc *, bool);
    217 static int ld_virtio_discard(struct ld_softc *, struct buf *);
    218 
    219 static int
    220 ld_virtio_alloc_reqs(struct ld_virtio_softc *sc, int qsize)
    221 {
    222 	int allocsize, r, rsegs, i;
    223 	struct ld_softc *ld = &sc->sc_ld;
    224 	void *vaddr;
    225 
    226 	allocsize = sizeof(struct virtio_blk_req) * qsize;
    227 	r = bus_dmamem_alloc(virtio_dmat(sc->sc_virtio), allocsize, 0, 0,
    228 			     &sc->sc_reqs_seg, 1, &rsegs, BUS_DMA_WAITOK);
    229 	if (r != 0) {
    230 		aprint_error_dev(sc->sc_dev,
    231 				 "DMA memory allocation failed, size %d, "
    232 				 "error code %d\n", allocsize, r);
    233 		goto err_none;
    234 	}
    235 	r = bus_dmamem_map(virtio_dmat(sc->sc_virtio),
    236 			   &sc->sc_reqs_seg, 1, allocsize,
    237 			   &vaddr, BUS_DMA_WAITOK);
    238 	if (r != 0) {
    239 		aprint_error_dev(sc->sc_dev,
    240 				 "DMA memory map failed, "
    241 				 "error code %d\n", r);
    242 		goto err_dmamem_alloc;
    243 	}
    244 	sc->sc_reqs = vaddr;
    245 	memset(vaddr, 0, allocsize);
    246 	for (i = 0; i < qsize; i++) {
    247 		struct virtio_blk_req *vr = &sc->sc_reqs[i];
    248 		r = bus_dmamap_create(virtio_dmat(sc->sc_virtio),
    249 				      offsetof(struct virtio_blk_req, vr_bp),
    250 				      1,
    251 				      offsetof(struct virtio_blk_req, vr_bp),
    252 				      0,
    253 				      BUS_DMA_WAITOK|BUS_DMA_ALLOCNOW,
    254 				      &vr->vr_cmdsts);
    255 		if (r != 0) {
    256 			aprint_error_dev(sc->sc_dev,
    257 					 "command dmamap creation failed, "
    258 					 "error code %d\n", r);
    259 			goto err_reqs;
    260 		}
    261 		r = bus_dmamap_load(virtio_dmat(sc->sc_virtio), vr->vr_cmdsts,
    262 				    &vr->vr_hdr,
    263 				    offsetof(struct virtio_blk_req, vr_bp),
    264 				    NULL, BUS_DMA_WAITOK);
    265 		if (r != 0) {
    266 			aprint_error_dev(sc->sc_dev,
    267 					 "command dmamap load failed, "
    268 					 "error code %d\n", r);
    269 			goto err_reqs;
    270 		}
    271 		r = bus_dmamap_create(virtio_dmat(sc->sc_virtio),
    272 				      /*size*/ld->sc_maxxfer,
    273 				      /*nseg*/sc->sc_seg_max,
    274 				      /*maxsegsz*/sc->sc_size_max,
    275 				      /*boundary*/0,
    276 				      BUS_DMA_WAITOK|BUS_DMA_ALLOCNOW,
    277 				      &vr->vr_payload);
    278 		if (r != 0) {
    279 			aprint_error_dev(sc->sc_dev,
    280 					 "payload dmamap creation failed, "
    281 					 "error code %d\n", r);
    282 			goto err_reqs;
    283 		}
    284 		vr->vr_datap = NULL;
    285 		vr->vr_datas = 0;
    286 	}
    287 	return 0;
    288 
    289 err_reqs:
    290 	for (i = 0; i < qsize; i++) {
    291 		struct virtio_blk_req *vr = &sc->sc_reqs[i];
    292 		if (vr->vr_cmdsts) {
    293 			bus_dmamap_destroy(virtio_dmat(sc->sc_virtio),
    294 					   vr->vr_cmdsts);
    295 			vr->vr_cmdsts = 0;
    296 		}
    297 		if (vr->vr_payload) {
    298 			bus_dmamap_destroy(virtio_dmat(sc->sc_virtio),
    299 					   vr->vr_payload);
    300 			vr->vr_payload = 0;
    301 		}
    302 	}
    303 	bus_dmamem_unmap(virtio_dmat(sc->sc_virtio), sc->sc_reqs, allocsize);
    304 err_dmamem_alloc:
    305 	bus_dmamem_free(virtio_dmat(sc->sc_virtio), &sc->sc_reqs_seg, 1);
    306 err_none:
    307 	return -1;
    308 }
    309 
    310 static void
    311 ld_virtio_attach(device_t parent, device_t self, void *aux)
    312 {
    313 	struct ld_virtio_softc *sc = device_private(self);
    314 	struct ld_softc *ld = &sc->sc_ld;
    315 	struct virtio_softc *vsc = device_private(parent);
    316 	uint64_t features;
    317 	int qsize;
    318 
    319 	if (virtio_child(vsc) != NULL) {
    320 		aprint_normal(": child already attached for %s; "
    321 			      "something wrong...\n", device_xname(parent));
    322 		return;
    323 	}
    324 
    325 	sc->sc_dev = self;
    326 	sc->sc_virtio = vsc;
    327 
    328 	virtio_child_attach_start(vsc, self, IPL_BIO,
    329 	    (VIRTIO_BLK_F_SIZE_MAX | VIRTIO_BLK_F_SEG_MAX |
    330 	     VIRTIO_BLK_F_GEOMETRY | VIRTIO_BLK_F_RO | VIRTIO_BLK_F_BLK_SIZE |
    331 	     VIRTIO_BLK_F_FLUSH | VIRTIO_BLK_F_TOPOLOGY |
    332 	     VIRTIO_BLK_F_CONFIG_WCE | VIRTIO_BLK_F_DISCARD),
    333 	    VIRTIO_BLK_FLAG_BITS);
    334 
    335 	features = virtio_features(vsc);
    336 	if (features == 0)
    337 		goto err;
    338 
    339 	if (features & VIRTIO_BLK_F_RO)
    340 		sc->sc_readonly = 1;
    341 	else
    342 		sc->sc_readonly = 0;
    343 
    344 	if (features & VIRTIO_BLK_F_BLK_SIZE) {
    345 		ld->sc_secsize = virtio_read_device_config_4(vsc,
    346 					VIRTIO_BLK_CONFIG_BLK_SIZE);
    347 	} else
    348 		ld->sc_secsize = VIRTIO_BLK_BSIZE;
    349 
    350 	if (features & VIRTIO_BLK_F_SEG_MAX) {
    351 		sc->sc_seg_max = virtio_read_device_config_4(vsc,
    352 		    VIRTIO_BLK_CONFIG_SEG_MAX);
    353 		if (sc->sc_seg_max == 0) {
    354 			aprint_error_dev(sc->sc_dev,
    355 			    "Invalid SEG_MAX %d\n", sc->sc_seg_max);
    356 			goto err;
    357 		}
    358 	} else {
    359 		sc->sc_seg_max = 1;
    360 		aprint_verbose_dev(sc->sc_dev,
    361 		    "Unknown SEG_MAX, assuming %"PRIu32"\n", sc->sc_seg_max);
    362 	}
    363 
    364 	/* At least genfs_io assumes size_max*seg_max >= MAXPHYS. */
    365 	if (features & VIRTIO_BLK_F_SIZE_MAX) {
    366 		sc->sc_size_max = virtio_read_device_config_4(vsc,
    367 		    VIRTIO_BLK_CONFIG_SIZE_MAX);
    368 		if (sc->sc_size_max < MAXPHYS/sc->sc_seg_max) {
    369 			aprint_error_dev(sc->sc_dev,
    370 			    "Too small SIZE_MAX %d minimum is %d\n",
    371 			    sc->sc_size_max, MAXPHYS/sc->sc_seg_max);
    372 			// goto err;
    373 			sc->sc_size_max = MAXPHYS/sc->sc_seg_max;
    374 		} else if (sc->sc_size_max > MAXPHYS) {
    375 			aprint_verbose_dev(sc->sc_dev,
    376 			    "Clip SIZE_MAX from %d to %d\n",
    377 			    sc->sc_size_max, MAXPHYS);
    378 			sc->sc_size_max = MAXPHYS;
    379 		}
    380 	} else {
    381 		sc->sc_size_max = MAXPHYS;
    382 		aprint_verbose_dev(sc->sc_dev,
    383 		    "Unknown SIZE_MAX, assuming %"PRIu32"\n",
    384 		    sc->sc_size_max);
    385 	}
    386 
    387 	aprint_normal_dev(sc->sc_dev, "max %"PRIu32" segs"
    388 	    " of max %"PRIu32" bytes\n",
    389 	    sc->sc_seg_max, sc->sc_size_max);
    390 
    391 	virtio_init_vq_vqdone(vsc, &sc->sc_vq, 0,
    392 	    ld_virtio_vq_done);
    393 
    394 	if (virtio_alloc_vq(vsc, &sc->sc_vq, sc->sc_size_max,
    395 		sc->sc_seg_max + VIRTIO_BLK_CTRL_SEGMENTS, "I/O request") != 0)
    396 		goto err;
    397 	qsize = sc->sc_vq.vq_num;
    398 
    399 	if (virtio_child_attach_finish(vsc, &sc->sc_vq, 1,
    400 	    NULL, VIRTIO_F_INTR_MSIX) != 0)
    401 		goto err;
    402 
    403 	ld->sc_dv = self;
    404 	ld->sc_secperunit = virtio_read_device_config_8(vsc,
    405 	    VIRTIO_BLK_CONFIG_CAPACITY) / (ld->sc_secsize / VIRTIO_BLK_BSIZE);
    406 
    407 	/*
    408 	 * Clamp ld->sc_maxxfer to MAXPHYS before ld_virtio_alloc_reqs
    409 	 * allocates DMA maps of at most ld->sc_maxxfer bytes.
    410 	 * ldattach will also clamp to MAXPHYS, but not until after
    411 	 * ld_virtio_alloc_reqs is done, so that doesn't help.
    412 	 */
    413 	ld->sc_maxxfer = MIN(MAXPHYS, sc->sc_size_max * sc->sc_seg_max);
    414 
    415 	if (features & VIRTIO_BLK_F_GEOMETRY) {
    416 		ld->sc_ncylinders = virtio_read_device_config_2(vsc,
    417 					VIRTIO_BLK_CONFIG_GEOMETRY_C);
    418 		ld->sc_nheads     = virtio_read_device_config_1(vsc,
    419 					VIRTIO_BLK_CONFIG_GEOMETRY_H);
    420 		ld->sc_nsectors   = virtio_read_device_config_1(vsc,
    421 					VIRTIO_BLK_CONFIG_GEOMETRY_S);
    422 	}
    423 	if (features & VIRTIO_BLK_F_TOPOLOGY) {
    424 		ld->sc_alignedsec = virtio_read_device_config_1(vsc,
    425 		    VIRTIO_BLK_CONFIG_ALIGNMENT_OFFSET);
    426 		ld->sc_physsecsize = ld->sc_secsize <<
    427 		    virtio_read_device_config_1(vsc,
    428 		    VIRTIO_BLK_CONFIG_PHYSICAL_BLOCK_EXP);
    429 	}
    430 	ld->sc_maxqueuecnt = qsize - 1; /* reserve slot for dumps, flushes */
    431 
    432 	if (ld_virtio_alloc_reqs(sc, qsize) < 0)
    433 		goto err;
    434 
    435 	cv_init(&sc->sc_sync_wait, "vblksync");
    436 	mutex_init(&sc->sc_sync_wait_lock, MUTEX_DEFAULT, IPL_BIO);
    437 	sc->sc_sync_use = SYNC_FREE;
    438 
    439 	ld->sc_dump = ld_virtio_dump;
    440 	ld->sc_start = ld_virtio_start;
    441 	ld->sc_ioctl = ld_virtio_ioctl;
    442 
    443 	if (ld_virtio_info(ld, true) == 0)
    444 		ld->sc_typename = sc->sc_typename;
    445 	else
    446 		ld->sc_typename = __UNCONST("Virtio Block Device");
    447 
    448 	if (features & VIRTIO_BLK_F_DISCARD) {
    449 		ld->sc_discard = ld_virtio_discard;
    450 		sc->sc_max_discard_sectors = virtio_read_device_config_4(vsc,
    451 		    VIRTIO_BLK_CONFIG_MAX_DISCARD_SECTORS);
    452 		sc->sc_max_discard_seg = virtio_read_device_config_4(vsc,
    453 		    VIRTIO_BLK_CONFIG_MAX_DISCARD_SEG);
    454 #if 0
    455 		sc->sc_discard_sector_alignment =
    456 		    virtio_read_device_config_4(vsc,
    457 		    VIRTIO_BLK_CONFIG_DISCARD_SECTOR_ALIGNMENT);
    458 #endif
    459 	}
    460 
    461 	ld->sc_flags = LDF_ENABLED | LDF_MPSAFE;
    462 	ldattach(ld, BUFQ_DISK_DEFAULT_STRAT);
    463 
    464 	return;
    465 
    466 err:
    467 	virtio_child_attach_failed(vsc);
    468 	return;
    469 }
    470 
    471 static int __used
    472 ld_virtio_info(struct ld_softc *ld, bool poll)
    473 {
    474 	struct ld_virtio_softc *sc = device_private(ld->sc_dv);
    475 	struct virtio_softc *vsc = sc->sc_virtio;
    476 	struct virtqueue *vq = &sc->sc_vq;
    477 	struct virtio_blk_req *vr;
    478 	int r;
    479 	int slot;
    480 	uint8_t *id_data; /* virtio v1.2 5.2.6 */
    481 	size_t id_len = 20;
    482 	bool unload = false;
    483 
    484 	if (sc->sc_typename != NULL) {
    485 		kmem_strfree(sc->sc_typename);
    486 		sc->sc_typename = NULL;
    487 	}
    488 
    489 	id_data = kmem_alloc(id_len, KM_SLEEP);
    490 
    491 	mutex_enter(&sc->sc_sync_wait_lock);
    492 	while (sc->sc_sync_use != SYNC_FREE) {
    493 		if (poll) {
    494 			mutex_exit(&sc->sc_sync_wait_lock);
    495 			ld_virtio_vq_done(vq);
    496 			mutex_enter(&sc->sc_sync_wait_lock);
    497 			continue;
    498 		}
    499 		cv_wait(&sc->sc_sync_wait, &sc->sc_sync_wait_lock);
    500 	}
    501 	sc->sc_sync_use = SYNC_BUSY;
    502 	mutex_exit(&sc->sc_sync_wait_lock);
    503 
    504 	r = virtio_enqueue_prep(vsc, vq, &slot);
    505 	if (r != 0)
    506 		goto done;
    507 
    508 	vr = &sc->sc_reqs[slot];
    509 	KASSERT(vr->vr_bp == NULL);
    510 
    511 	r = bus_dmamap_load(virtio_dmat(vsc), vr->vr_payload,
    512 			    id_data, id_len, NULL,
    513 			    BUS_DMA_READ|BUS_DMA_NOWAIT);
    514 	if (r != 0) {
    515 		aprint_error_dev(sc->sc_dev,
    516 		    "payload dmamap failed, error code %d\n", r);
    517 		virtio_enqueue_abort(vsc, vq, slot);
    518 		goto done;
    519 	}
    520 	unload = true;
    521 
    522 	KASSERT(vr->vr_payload->dm_nsegs <= sc->sc_seg_max);
    523 	r = virtio_enqueue_reserve(vsc, vq, slot, vr->vr_payload->dm_nsegs +
    524 	    VIRTIO_BLK_CTRL_SEGMENTS);
    525 	if (r != 0) {
    526 		bus_dmamap_unload(virtio_dmat(vsc), vr->vr_payload);
    527 		goto done;
    528 	}
    529 
    530 	vr->vr_bp = DUMMY_VR_BP;
    531 	vr->vr_hdr.type   = virtio_rw32(vsc, VIRTIO_BLK_T_GET_ID);
    532 	vr->vr_hdr.ioprio = virtio_rw32(vsc, 0);
    533 	vr->vr_hdr.sector = virtio_rw64(vsc, 0);
    534 
    535 	bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
    536 			0, sizeof(struct virtio_blk_req_hdr),
    537 			BUS_DMASYNC_PREWRITE);
    538 	bus_dmamap_sync(virtio_dmat(vsc), vr->vr_payload,
    539 			0, id_len,
    540 			BUS_DMASYNC_PREREAD);
    541 	bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
    542 			offsetof(struct virtio_blk_req, vr_status),
    543 			sizeof(uint8_t),
    544 			BUS_DMASYNC_PREREAD);
    545 
    546 	virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
    547 			 0, sizeof(struct virtio_blk_req_hdr),
    548 			 true);
    549 	virtio_enqueue(vsc, vq, slot, vr->vr_payload, false);
    550 	virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
    551 			 offsetof(struct virtio_blk_req, vr_status),
    552 			 sizeof(uint8_t),
    553 	                 false);
    554 	virtio_enqueue_commit(vsc, vq, slot, true);
    555 
    556 done:
    557 	mutex_enter(&sc->sc_sync_wait_lock);
    558 	while (sc->sc_sync_use != SYNC_DONE) {
    559 		if (poll) {
    560 			mutex_exit(&sc->sc_sync_wait_lock);
    561 			ld_virtio_vq_done(vq);
    562 			mutex_enter(&sc->sc_sync_wait_lock);
    563 			continue;
    564 		}
    565 		cv_wait(&sc->sc_sync_wait, &sc->sc_sync_wait_lock);
    566 	}
    567 
    568 	if (sc->sc_sync_status == VIRTIO_BLK_S_OK)
    569 		r = 0;
    570 	else
    571 		r = EIO;
    572 
    573 	sc->sc_sync_use = SYNC_FREE;
    574 	cv_broadcast(&sc->sc_sync_wait);
    575 	mutex_exit(&sc->sc_sync_wait_lock);
    576 
    577 	if (unload) {
    578 		bus_dmamap_sync(virtio_dmat(vsc), vr->vr_payload,
    579 				0, id_len, BUS_DMASYNC_POSTREAD);
    580 		bus_dmamap_unload(virtio_dmat(vsc), vr->vr_payload);
    581 	}
    582 
    583 	if (r == 0) {
    584 		if (id_data[0] == '\0')
    585 			r = ENOENT;
    586 		else
    587 			sc->sc_typename = kmem_strndup(id_data, id_len, KM_NOSLEEP);
    588 	}
    589 
    590 	kmem_free(id_data, id_len);
    591 
    592 	return r;
    593 }
    594 
    595 static int
    596 ld_virtio_start(struct ld_softc *ld, struct buf *bp)
    597 {
    598 	/* splbio */
    599 	struct ld_virtio_softc *sc = device_private(ld->sc_dv);
    600 	struct virtio_softc *vsc = sc->sc_virtio;
    601 	struct virtqueue *vq = &sc->sc_vq;
    602 	struct virtio_blk_req *vr;
    603 	int r;
    604 	int isread = (bp->b_flags & B_READ);
    605 	int slot;
    606 
    607 	if (sc->sc_readonly && !isread)
    608 		return EIO;
    609 
    610 	r = virtio_enqueue_prep(vsc, vq, &slot);
    611 	if (r != 0)
    612 		return r;
    613 
    614 	vr = &sc->sc_reqs[slot];
    615 	KASSERT(vr->vr_bp == NULL);
    616 
    617 	r = bus_dmamap_load(virtio_dmat(vsc), vr->vr_payload,
    618 			    bp->b_data, bp->b_bcount, NULL,
    619 			    ((isread?BUS_DMA_READ:BUS_DMA_WRITE)
    620 			     |BUS_DMA_NOWAIT));
    621 	if (r != 0) {
    622 		aprint_error_dev(sc->sc_dev,
    623 		    "payload dmamap failed, error code %d\n", r);
    624 		virtio_enqueue_abort(vsc, vq, slot);
    625 		return r;
    626 	}
    627 
    628 	KASSERT(vr->vr_payload->dm_nsegs <= sc->sc_seg_max);
    629 	r = virtio_enqueue_reserve(vsc, vq, slot, vr->vr_payload->dm_nsegs +
    630 	    VIRTIO_BLK_CTRL_SEGMENTS);
    631 	if (r != 0) {
    632 		bus_dmamap_unload(virtio_dmat(vsc), vr->vr_payload);
    633 		return r;
    634 	}
    635 
    636 	vr->vr_bp = bp;
    637 	vr->vr_hdr.type   = virtio_rw32(vsc,
    638 			isread ? VIRTIO_BLK_T_IN : VIRTIO_BLK_T_OUT);
    639 	vr->vr_hdr.ioprio = virtio_rw32(vsc, 0);
    640 	vr->vr_hdr.sector = virtio_rw64(vsc,
    641 			bp->b_rawblkno * sc->sc_ld.sc_secsize /
    642 			VIRTIO_BLK_BSIZE);
    643 
    644 	bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
    645 			0, sizeof(struct virtio_blk_req_hdr),
    646 			BUS_DMASYNC_PREWRITE);
    647 	bus_dmamap_sync(virtio_dmat(vsc), vr->vr_payload,
    648 			0, bp->b_bcount,
    649 			isread?BUS_DMASYNC_PREREAD:BUS_DMASYNC_PREWRITE);
    650 	bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
    651 			offsetof(struct virtio_blk_req, vr_status),
    652 			sizeof(uint8_t),
    653 			BUS_DMASYNC_PREREAD);
    654 
    655 	virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
    656 			 0, sizeof(struct virtio_blk_req_hdr),
    657 			 true);
    658 	virtio_enqueue(vsc, vq, slot, vr->vr_payload, !isread);
    659 	virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
    660 			 offsetof(struct virtio_blk_req, vr_status),
    661 			 sizeof(uint8_t),
    662 			 false);
    663 	virtio_enqueue_commit(vsc, vq, slot, true);
    664 
    665 	return 0;
    666 }
    667 
    668 static void
    669 ld_virtio_vq_done1(struct ld_virtio_softc *sc, struct virtio_softc *vsc,
    670 		   struct virtqueue *vq, int slot)
    671 {
    672 	struct virtio_blk_req *vr = &sc->sc_reqs[slot];
    673 	struct buf *bp = vr->vr_bp;
    674 	const uint32_t rt = virtio_rw32(vsc, vr->vr_hdr.type);
    675 
    676 	vr->vr_bp = NULL;
    677 
    678 	bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
    679 			0, sizeof(struct virtio_blk_req_hdr),
    680 			BUS_DMASYNC_POSTWRITE);
    681 	bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
    682 			sizeof(struct virtio_blk_req_hdr), sizeof(uint8_t),
    683 			BUS_DMASYNC_POSTREAD);
    684 	if (bp == DUMMY_VR_BP) {
    685 		mutex_enter(&sc->sc_sync_wait_lock);
    686 		sc->sc_sync_status = vr->vr_status;
    687 		sc->sc_sync_use = SYNC_DONE;
    688 		cv_broadcast(&sc->sc_sync_wait);
    689 		mutex_exit(&sc->sc_sync_wait_lock);
    690 		virtio_dequeue_commit(vsc, vq, slot);
    691 		return;
    692 	}
    693 	switch (rt) {
    694 	case VIRTIO_BLK_T_OUT:
    695 	case VIRTIO_BLK_T_IN:
    696 		bus_dmamap_sync(virtio_dmat(vsc), vr->vr_payload,
    697 				0, bp->b_bcount,
    698 				(bp->b_flags & B_READ)?BUS_DMASYNC_POSTREAD
    699 						      :BUS_DMASYNC_POSTWRITE);
    700 		break;
    701 	default:
    702 		if (vr->vr_datap == NULL)
    703 			break;
    704 		bus_dmamap_sync(virtio_dmat(vsc), vr->vr_payload,
    705 				0, vr->vr_datas, BUS_DMASYNC_POSTREAD |
    706 				BUS_DMASYNC_POSTWRITE);
    707 		break;
    708 	}
    709 	bus_dmamap_unload(virtio_dmat(vsc), vr->vr_payload);
    710 
    711 	if (vr->vr_status != VIRTIO_BLK_S_OK) {
    712 		bp->b_error = EIO;
    713 		bp->b_resid = bp->b_bcount;
    714 	} else {
    715 		bp->b_error = 0;
    716 		bp->b_resid = 0;
    717 	}
    718 
    719 	if (vr->vr_datap != NULL) {
    720 		kmem_free(vr->vr_datap, vr->vr_datas);
    721 		vr->vr_datap = NULL;
    722 		vr->vr_datas = 0;
    723 	}
    724 
    725 	virtio_dequeue_commit(vsc, vq, slot);
    726 
    727 	switch (rt) {
    728 	case VIRTIO_BLK_T_OUT:
    729 	case VIRTIO_BLK_T_IN:
    730 		lddone(&sc->sc_ld, bp);
    731 		break;
    732 	case VIRTIO_BLK_T_DISCARD:
    733 		lddiscardend(&sc->sc_ld, bp);
    734 		break;
    735 	}
    736 }
    737 
    738 static int
    739 ld_virtio_vq_done(struct virtqueue *vq)
    740 {
    741 	struct virtio_softc *vsc = vq->vq_owner;
    742 	struct ld_virtio_softc *sc = device_private(virtio_child(vsc));
    743 	int r = 0;
    744 	int slot;
    745 
    746 again:
    747 	if (virtio_dequeue(vsc, vq, &slot, NULL))
    748 		return r;
    749 	r = 1;
    750 
    751 	ld_virtio_vq_done1(sc, vsc, vq, slot);
    752 	goto again;
    753 }
    754 
    755 static int
    756 ld_virtio_dump(struct ld_softc *ld, void *data, daddr_t blkno, int blkcnt)
    757 {
    758 	struct ld_virtio_softc *sc = device_private(ld->sc_dv);
    759 	struct virtio_softc *vsc = sc->sc_virtio;
    760 	struct virtqueue *vq = &sc->sc_vq;
    761 	struct virtio_blk_req *vr;
    762 	int slot, r;
    763 
    764 	if (sc->sc_readonly)
    765 		return EIO;
    766 
    767 	r = virtio_enqueue_prep(vsc, vq, &slot);
    768 	if (r != 0) {
    769 		if (r == EAGAIN) { /* no free slot; dequeue first */
    770 			delay(100);
    771 			ld_virtio_vq_done(vq);
    772 			r = virtio_enqueue_prep(vsc, vq, &slot);
    773 			if (r != 0)
    774 				return r;
    775 		}
    776 		return r;
    777 	}
    778 	vr = &sc->sc_reqs[slot];
    779 	r = bus_dmamap_load(virtio_dmat(vsc), vr->vr_payload,
    780 			    data, blkcnt*ld->sc_secsize, NULL,
    781 			    BUS_DMA_WRITE|BUS_DMA_NOWAIT);
    782 	if (r != 0)
    783 		return r;
    784 
    785 	r = virtio_enqueue_reserve(vsc, vq, slot, vr->vr_payload->dm_nsegs +
    786 	    VIRTIO_BLK_CTRL_SEGMENTS);
    787 	if (r != 0) {
    788 		bus_dmamap_unload(virtio_dmat(vsc), vr->vr_payload);
    789 		return r;
    790 	}
    791 
    792 	vr->vr_bp = (void*)0xdeadbeef;
    793 	vr->vr_hdr.type   = virtio_rw32(vsc, VIRTIO_BLK_T_OUT);
    794 	vr->vr_hdr.ioprio = virtio_rw32(vsc, 0);
    795 	vr->vr_hdr.sector = virtio_rw64(vsc,
    796 			blkno * ld->sc_secsize /
    797 			VIRTIO_BLK_BSIZE);
    798 
    799 	bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
    800 			0, sizeof(struct virtio_blk_req_hdr),
    801 			BUS_DMASYNC_PREWRITE);
    802 	bus_dmamap_sync(virtio_dmat(vsc), vr->vr_payload,
    803 			0, blkcnt*ld->sc_secsize,
    804 			BUS_DMASYNC_PREWRITE);
    805 	bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
    806 			offsetof(struct virtio_blk_req, vr_status),
    807 			sizeof(uint8_t),
    808 			BUS_DMASYNC_PREREAD);
    809 
    810 	virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
    811 			 0, sizeof(struct virtio_blk_req_hdr),
    812 			 true);
    813 	virtio_enqueue(vsc, vq, slot, vr->vr_payload, true);
    814 	virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
    815 			 offsetof(struct virtio_blk_req, vr_status),
    816 			 sizeof(uint8_t),
    817 			 false);
    818 	virtio_enqueue_commit(vsc, vq, slot, true);
    819 
    820 	for ( ; ; ) {
    821 		int dslot;
    822 
    823 		r = virtio_dequeue(vsc, vq, &dslot, NULL);
    824 		if (r != 0)
    825 			continue;
    826 		if (dslot != slot) {
    827 			ld_virtio_vq_done1(sc, vsc, vq, dslot);
    828 			continue;
    829 		} else
    830 			break;
    831 	}
    832 
    833 	bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
    834 			0, sizeof(struct virtio_blk_req_hdr),
    835 			BUS_DMASYNC_POSTWRITE);
    836 	bus_dmamap_sync(virtio_dmat(vsc), vr->vr_payload,
    837 			0, blkcnt*ld->sc_secsize,
    838 			BUS_DMASYNC_POSTWRITE);
    839 	bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
    840 			offsetof(struct virtio_blk_req, vr_status),
    841 			sizeof(uint8_t),
    842 			BUS_DMASYNC_POSTREAD);
    843 	if (vr->vr_status == VIRTIO_BLK_S_OK)
    844 		r = 0;
    845 	else
    846 		r = EIO;
    847 	virtio_dequeue_commit(vsc, vq, slot);
    848 
    849 	return r;
    850 }
    851 
    852 static int
    853 ld_virtio_detach(device_t self, int flags)
    854 {
    855 	struct ld_virtio_softc *sc = device_private(self);
    856 	struct ld_softc *ld = &sc->sc_ld;
    857 	bus_dma_tag_t dmat = virtio_dmat(sc->sc_virtio);
    858 	int r, i, qsize;
    859 
    860 	qsize = sc->sc_vq.vq_num;
    861 	r = ldbegindetach(ld, flags);
    862 	if (r != 0)
    863 		return r;
    864 	virtio_reset(sc->sc_virtio);
    865 	virtio_free_vq(sc->sc_virtio, &sc->sc_vq);
    866 
    867 	for (i = 0; i < qsize; i++) {
    868 		bus_dmamap_destroy(dmat,
    869 				   sc->sc_reqs[i].vr_cmdsts);
    870 		bus_dmamap_destroy(dmat,
    871 				   sc->sc_reqs[i].vr_payload);
    872 	}
    873 	bus_dmamem_unmap(dmat, sc->sc_reqs,
    874 			 sizeof(struct virtio_blk_req) * qsize);
    875 	bus_dmamem_free(dmat, &sc->sc_reqs_seg, 1);
    876 
    877 	ldenddetach(ld);
    878 
    879 	if (sc->sc_typename != NULL)
    880 		kmem_strfree(sc->sc_typename);
    881 
    882 	cv_destroy(&sc->sc_sync_wait);
    883 	mutex_destroy(&sc->sc_sync_wait_lock);
    884 
    885 	virtio_child_detach(sc->sc_virtio);
    886 
    887 	return 0;
    888 }
    889 
    890 static int
    891 ld_virtio_flush(struct ld_softc *ld, bool poll)
    892 {
    893 	struct ld_virtio_softc * const sc = device_private(ld->sc_dv);
    894 	struct virtio_softc * const vsc = sc->sc_virtio;
    895 	const uint64_t features = virtio_features(vsc);
    896 	struct virtqueue *vq = &sc->sc_vq;
    897 	struct virtio_blk_req *vr;
    898 	int slot;
    899 	int r;
    900 
    901 	if ((features & VIRTIO_BLK_F_FLUSH) == 0)
    902 		return 0;
    903 
    904 	mutex_enter(&sc->sc_sync_wait_lock);
    905 	while (sc->sc_sync_use != SYNC_FREE) {
    906 		if (poll) {
    907 			mutex_exit(&sc->sc_sync_wait_lock);
    908 			ld_virtio_vq_done(vq);
    909 			mutex_enter(&sc->sc_sync_wait_lock);
    910 			continue;
    911 		}
    912 		cv_wait(&sc->sc_sync_wait, &sc->sc_sync_wait_lock);
    913 	}
    914 	sc->sc_sync_use = SYNC_BUSY;
    915 	mutex_exit(&sc->sc_sync_wait_lock);
    916 
    917 	r = virtio_enqueue_prep(vsc, vq, &slot);
    918 	if (r != 0) {
    919 		return r;
    920 	}
    921 
    922 	vr = &sc->sc_reqs[slot];
    923 	KASSERT(vr->vr_bp == NULL);
    924 
    925 	r = virtio_enqueue_reserve(vsc, vq, slot, VIRTIO_BLK_CTRL_SEGMENTS);
    926 	if (r != 0) {
    927 		return r;
    928 	}
    929 
    930 	vr->vr_bp = DUMMY_VR_BP;
    931 	vr->vr_hdr.type   = virtio_rw32(vsc, VIRTIO_BLK_T_FLUSH);
    932 	vr->vr_hdr.ioprio = virtio_rw32(vsc, 0);
    933 	vr->vr_hdr.sector = virtio_rw64(vsc, 0);
    934 
    935 	bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
    936 			0, sizeof(struct virtio_blk_req_hdr),
    937 			BUS_DMASYNC_PREWRITE);
    938 	bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
    939 			offsetof(struct virtio_blk_req, vr_status),
    940 			sizeof(uint8_t),
    941 			BUS_DMASYNC_PREREAD);
    942 
    943 	virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
    944 			 0, sizeof(struct virtio_blk_req_hdr),
    945 			 true);
    946 	virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
    947 			 offsetof(struct virtio_blk_req, vr_status),
    948 			 sizeof(uint8_t),
    949 			 false);
    950 	virtio_enqueue_commit(vsc, vq, slot, true);
    951 
    952 	mutex_enter(&sc->sc_sync_wait_lock);
    953 	while (sc->sc_sync_use != SYNC_DONE) {
    954 		if (poll) {
    955 			mutex_exit(&sc->sc_sync_wait_lock);
    956 			ld_virtio_vq_done(vq);
    957 			mutex_enter(&sc->sc_sync_wait_lock);
    958 			continue;
    959 		}
    960 		cv_wait(&sc->sc_sync_wait, &sc->sc_sync_wait_lock);
    961 	}
    962 
    963 	if (sc->sc_sync_status == VIRTIO_BLK_S_OK)
    964 		r = 0;
    965 	else
    966 		r = EIO;
    967 
    968 	sc->sc_sync_use = SYNC_FREE;
    969 	cv_broadcast(&sc->sc_sync_wait);
    970 	mutex_exit(&sc->sc_sync_wait_lock);
    971 
    972 	return r;
    973 }
    974 
    975 static int
    976 ld_virtio_getcache(struct ld_softc *ld, int *bitsp)
    977 {
    978 	struct ld_virtio_softc * const sc = device_private(ld->sc_dv);
    979 	struct virtio_softc * const vsc = sc->sc_virtio;
    980 	const uint64_t features = virtio_features(vsc);
    981 
    982 	*bitsp = DKCACHE_READ;
    983 	if ((features & VIRTIO_BLK_F_CONFIG_WCE) != 0)
    984 		*bitsp |= DKCACHE_WCHANGE;
    985 	if (virtio_read_device_config_1(vsc,
    986 	    VIRTIO_BLK_CONFIG_WRITEBACK) != 0x00)
    987 		*bitsp |= DKCACHE_WRITE;
    988 
    989 	return 0;
    990 }
    991 
    992 static int
    993 ld_virtio_setcache(struct ld_softc *ld, int bits)
    994 {
    995 	struct ld_virtio_softc * const sc = device_private(ld->sc_dv);
    996 	struct virtio_softc * const vsc = sc->sc_virtio;
    997 	const uint8_t wce = (bits & DKCACHE_WRITE) ? 0x01 : 0x00;
    998 
    999 	virtio_write_device_config_1(vsc,
   1000 	    VIRTIO_BLK_CONFIG_WRITEBACK, wce);
   1001 	if (virtio_read_device_config_1(vsc,
   1002 	    VIRTIO_BLK_CONFIG_WRITEBACK) != wce)
   1003 		return EIO;
   1004 
   1005 	return 0;
   1006 }
   1007 
   1008 static int
   1009 ld_virtio_ioctl(struct ld_softc *ld, u_long cmd, void *addr, int32_t flag, bool poll)
   1010 {
   1011 	int error;
   1012 
   1013 	switch (cmd) {
   1014 	case DIOCCACHESYNC:
   1015 		error = ld_virtio_flush(ld, poll);
   1016 		break;
   1017 
   1018 	case DIOCGCACHE:
   1019 		error = ld_virtio_getcache(ld, (int *)addr);
   1020 		break;
   1021 
   1022 	case DIOCSCACHE:
   1023 		error = ld_virtio_setcache(ld, *(int *)addr);
   1024 		break;
   1025 
   1026 	default:
   1027 		error = EPASSTHROUGH;
   1028 		break;
   1029 	}
   1030 
   1031 	return error;
   1032 }
   1033 
   1034 static int
   1035 ld_virtio_discard(struct ld_softc *ld, struct buf *bp)
   1036 {
   1037 	struct ld_virtio_softc * const sc = device_private(ld->sc_dv);
   1038 	struct virtio_softc * const vsc = sc->sc_virtio;
   1039 	struct virtqueue * const vq = &sc->sc_vq;
   1040 	struct virtio_blk_req *vr;
   1041 	const uint64_t features = virtio_features(vsc);
   1042 	int r;
   1043 	int slot;
   1044 	uint64_t blkno;
   1045 	uint32_t nblks;
   1046 	struct virtio_blk_discard_write_zeroes * dwz;
   1047 
   1048 	if ((features & VIRTIO_BLK_F_DISCARD) == 0 ||
   1049 	    sc->sc_max_discard_seg < 1)
   1050 		return EINVAL;
   1051 
   1052 	if (sc->sc_readonly)
   1053 		return EIO;
   1054 
   1055 	blkno = bp->b_rawblkno * sc->sc_ld.sc_secsize / VIRTIO_BLK_BSIZE;
   1056 	nblks = bp->b_bcount / VIRTIO_BLK_BSIZE;
   1057 
   1058 	if (nblks > sc->sc_max_discard_sectors)
   1059 		return ERANGE;
   1060 
   1061 	r = virtio_enqueue_prep(vsc, vq, &slot);
   1062 	if (r != 0) {
   1063 		return r;
   1064 	}
   1065 
   1066 	vr = &sc->sc_reqs[slot];
   1067 	KASSERT(vr->vr_bp == NULL);
   1068 
   1069 	dwz = kmem_alloc(sizeof(*dwz), KM_SLEEP);
   1070 
   1071 	r = bus_dmamap_load(virtio_dmat(vsc), vr->vr_payload,
   1072 	    dwz, sizeof(*dwz), NULL, BUS_DMA_WRITE | BUS_DMA_NOWAIT);
   1073 	if (r != 0) {
   1074 		device_printf(sc->sc_dev,
   1075 		    "discard payload dmamap failed, error code %d\n", r);
   1076 		virtio_enqueue_abort(vsc, vq, slot);
   1077 		kmem_free(dwz, sizeof(*dwz));
   1078 		return r;
   1079 	}
   1080 
   1081 	KASSERT(vr->vr_payload->dm_nsegs <= sc->sc_seg_max);
   1082 	r = virtio_enqueue_reserve(vsc, vq, slot, vr->vr_payload->dm_nsegs +
   1083 	    VIRTIO_BLK_CTRL_SEGMENTS);
   1084 	if (r != 0) {
   1085 		bus_dmamap_unload(virtio_dmat(vsc), vr->vr_payload);
   1086 		kmem_free(dwz, sizeof(*dwz));
   1087 		return r;
   1088 	}
   1089 
   1090 	vr->vr_hdr.type = virtio_rw32(vsc, VIRTIO_BLK_T_DISCARD);
   1091 	vr->vr_hdr.ioprio = virtio_rw32(vsc, 0);
   1092 	vr->vr_hdr.sector = virtio_rw64(vsc, 0);
   1093 	vr->vr_bp = bp;
   1094 
   1095 	KASSERT(vr->vr_datap == NULL);
   1096 	vr->vr_datap = dwz;
   1097 	vr->vr_datas = sizeof(*dwz);
   1098 
   1099 	dwz->sector = virtio_rw64(vsc, blkno);
   1100 	dwz->num_sectors = virtio_rw32(vsc, nblks);
   1101 	dwz->flags = virtio_rw32(vsc, 0);
   1102 
   1103 	bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
   1104 			0, sizeof(struct virtio_blk_req_hdr),
   1105 			BUS_DMASYNC_PREWRITE);
   1106 	bus_dmamap_sync(virtio_dmat(vsc), vr->vr_payload,
   1107 			0, vr->vr_datas, BUS_DMASYNC_PREWRITE);
   1108 	bus_dmamap_sync(virtio_dmat(vsc), vr->vr_cmdsts,
   1109 			offsetof(struct virtio_blk_req, vr_status),
   1110 			sizeof(uint8_t),
   1111 			BUS_DMASYNC_PREREAD);
   1112 
   1113 	virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
   1114 			 0, sizeof(struct virtio_blk_req_hdr),
   1115 			 true);
   1116 	virtio_enqueue(vsc, vq, slot, vr->vr_payload, true);
   1117 	virtio_enqueue_p(vsc, vq, slot, vr->vr_cmdsts,
   1118 			 offsetof(struct virtio_blk_req, vr_status),
   1119 			 sizeof(uint8_t),
   1120 			 false);
   1121 	virtio_enqueue_commit(vsc, vq, slot, true);
   1122 
   1123 	return 0;
   1124 }
   1125 
   1126 MODULE(MODULE_CLASS_DRIVER, ld_virtio, "ld,virtio");
   1127 
   1128 static int
   1129 ld_virtio_modcmd(modcmd_t cmd, void *opaque)
   1130 {
   1131 	int error = 0;
   1132 
   1133 	switch (cmd) {
   1134 	case MODULE_CMD_INIT:
   1135 #ifdef _MODULE
   1136 		error = config_init_component(cfdriver_ioconf_ld_virtio,
   1137 		    cfattach_ioconf_ld_virtio, cfdata_ioconf_ld_virtio);
   1138 #endif
   1139 		break;
   1140 	case MODULE_CMD_FINI:
   1141 #ifdef _MODULE
   1142 		error = config_fini_component(cfdriver_ioconf_ld_virtio,
   1143 		    cfattach_ioconf_ld_virtio, cfdata_ioconf_ld_virtio);
   1144 #endif
   1145 		break;
   1146 	default:
   1147 		error = ENOTTY;
   1148 		break;
   1149 	}
   1150 
   1151 	return error;
   1152 }
   1153