1 /*- 2 * Copyright (c) 2011, Bryan Venteicher <bryanv@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice unmodified, this list of conditions, and the following 10 * disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 /* Driver for VirtIO block devices. */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/param.h> 33 #include <sys/systm.h> 34 #include <sys/kernel.h> 35 #include <sys/bio.h> 36 #include <sys/malloc.h> 37 #include <sys/module.h> 38 #include <sys/sglist.h> 39 #include <sys/sysctl.h> 40 #include <sys/lock.h> 41 #include <sys/mutex.h> 42 #include <sys/queue.h> 43 44 #include <geom/geom_disk.h> 45 46 #include <machine/bus.h> 47 #include <machine/resource.h> 48 #include <sys/bus.h> 49 #include <sys/rman.h> 50 51 #include <dev/virtio/virtio.h> 52 #include <dev/virtio/virtqueue.h> 53 #include <dev/virtio/block/virtio_blk.h> 54 55 #include "virtio_if.h" 56 57 struct vtblk_request { 58 struct virtio_blk_outhdr vbr_hdr; 59 struct bio *vbr_bp; 60 uint8_t vbr_ack; 61 62 TAILQ_ENTRY(vtblk_request) vbr_link; 63 }; 64 65 enum vtblk_cache_mode { 66 VTBLK_CACHE_WRITETHROUGH, 67 VTBLK_CACHE_WRITEBACK, 68 VTBLK_CACHE_MAX 69 }; 70 71 struct vtblk_softc { 72 device_t vtblk_dev; 73 struct mtx vtblk_mtx; 74 uint64_t vtblk_features; 75 uint32_t vtblk_flags; 76 #define VTBLK_FLAG_INDIRECT 0x0001 77 #define VTBLK_FLAG_READONLY 0x0002 78 #define VTBLK_FLAG_DETACH 0x0004 79 #define VTBLK_FLAG_SUSPEND 0x0008 80 #define VTBLK_FLAG_DUMPING 0x0010 81 #define VTBLK_FLAG_BARRIER 0x0020 82 #define VTBLK_FLAG_WC_CONFIG 0x0040 83 84 struct virtqueue *vtblk_vq; 85 struct sglist *vtblk_sglist; 86 struct disk *vtblk_disk; 87 88 struct bio_queue_head vtblk_bioq; 89 TAILQ_HEAD(, vtblk_request) 90 vtblk_req_free; 91 TAILQ_HEAD(, vtblk_request) 92 vtblk_req_ready; 93 struct vtblk_request *vtblk_req_ordered; 94 95 int vtblk_max_nsegs; 96 int vtblk_request_count; 97 enum vtblk_cache_mode vtblk_write_cache; 98 99 struct vtblk_request vtblk_dump_request; 100 }; 101 102 static struct virtio_feature_desc vtblk_feature_desc[] = { 103 { VIRTIO_BLK_F_BARRIER, "HostBarrier" }, 104 { VIRTIO_BLK_F_SIZE_MAX, "MaxSegSize" }, 105 { VIRTIO_BLK_F_SEG_MAX, "MaxNumSegs" }, 106 { VIRTIO_BLK_F_GEOMETRY, "DiskGeometry" }, 107 { VIRTIO_BLK_F_RO, "ReadOnly" }, 108 { VIRTIO_BLK_F_BLK_SIZE, "BlockSize" }, 109 { VIRTIO_BLK_F_SCSI, "SCSICmds" }, 110 { VIRTIO_BLK_F_WCE, "WriteCache" }, 111 { VIRTIO_BLK_F_TOPOLOGY, "Topology" }, 112 { VIRTIO_BLK_F_CONFIG_WCE, "ConfigWCE" }, 113 114 { 0, NULL } 115 }; 116 117 static int vtblk_modevent(module_t, int, void *); 118 119 static int vtblk_probe(device_t); 120 static int vtblk_attach(device_t); 121 static int vtblk_detach(device_t); 122 static int vtblk_suspend(device_t); 123 static int vtblk_resume(device_t); 124 static int vtblk_shutdown(device_t); 125 static int vtblk_config_change(device_t); 126 127 static int vtblk_open(struct disk *); 128 static int vtblk_close(struct disk *); 129 static int vtblk_ioctl(struct disk *, u_long, void *, int, 130 struct thread *); 131 static int vtblk_dump(void *, void *, vm_offset_t, off_t, size_t); 132 static void vtblk_strategy(struct bio *); 133 134 static void vtblk_negotiate_features(struct vtblk_softc *); 135 static int vtblk_maximum_segments(struct vtblk_softc *, 136 struct virtio_blk_config *); 137 static int vtblk_alloc_virtqueue(struct vtblk_softc *); 138 static void vtblk_resize_disk(struct vtblk_softc *, uint64_t); 139 static void vtblk_set_write_cache(struct vtblk_softc *, int); 140 static int vtblk_write_cache_enabled(struct vtblk_softc *sc, 141 struct virtio_blk_config *); 142 static int vtblk_write_cache_sysctl(SYSCTL_HANDLER_ARGS); 143 static void vtblk_alloc_disk(struct vtblk_softc *, 144 struct virtio_blk_config *); 145 static void vtblk_create_disk(struct vtblk_softc *); 146 147 static int vtblk_quiesce(struct vtblk_softc *); 148 static void vtblk_startio(struct vtblk_softc *); 149 static struct vtblk_request * vtblk_bio_request(struct vtblk_softc *); 150 static int vtblk_execute_request(struct vtblk_softc *, 151 struct vtblk_request *); 152 153 static void vtblk_vq_intr(void *); 154 155 static void vtblk_stop(struct vtblk_softc *); 156 157 static void vtblk_read_config(struct vtblk_softc *, 158 struct virtio_blk_config *); 159 static void vtblk_get_ident(struct vtblk_softc *); 160 static void vtblk_prepare_dump(struct vtblk_softc *); 161 static int vtblk_write_dump(struct vtblk_softc *, void *, off_t, size_t); 162 static int vtblk_flush_dump(struct vtblk_softc *); 163 static int vtblk_poll_request(struct vtblk_softc *, 164 struct vtblk_request *); 165 166 static void vtblk_finish_completed(struct vtblk_softc *); 167 static void vtblk_drain_vq(struct vtblk_softc *, int); 168 static void vtblk_drain(struct vtblk_softc *); 169 170 static int vtblk_alloc_requests(struct vtblk_softc *); 171 static void vtblk_free_requests(struct vtblk_softc *); 172 static struct vtblk_request * vtblk_dequeue_request(struct vtblk_softc *); 173 static void vtblk_enqueue_request(struct vtblk_softc *, 174 struct vtblk_request *); 175 176 static struct vtblk_request * vtblk_dequeue_ready(struct vtblk_softc *); 177 static void vtblk_enqueue_ready(struct vtblk_softc *, 178 struct vtblk_request *); 179 180 static int vtblk_request_error(struct vtblk_request *); 181 static void vtblk_finish_bio(struct bio *, int); 182 183 static void vtblk_setup_sysctl(struct vtblk_softc *); 184 static int vtblk_tunable_int(struct vtblk_softc *, const char *, int); 185 186 /* Tunables. */ 187 static int vtblk_no_ident = 0; 188 TUNABLE_INT("hw.vtblk.no_ident", &vtblk_no_ident); 189 static int vtblk_writecache_mode = -1; 190 TUNABLE_INT("hw.vtblk.writecache_mode", &vtblk_writecache_mode); 191 192 /* Features desired/implemented by this driver. */ 193 #define VTBLK_FEATURES \ 194 (VIRTIO_BLK_F_BARRIER | \ 195 VIRTIO_BLK_F_SIZE_MAX | \ 196 VIRTIO_BLK_F_SEG_MAX | \ 197 VIRTIO_BLK_F_GEOMETRY | \ 198 VIRTIO_BLK_F_RO | \ 199 VIRTIO_BLK_F_BLK_SIZE | \ 200 VIRTIO_BLK_F_WCE | \ 201 VIRTIO_BLK_F_CONFIG_WCE | \ 202 VIRTIO_RING_F_INDIRECT_DESC) 203 204 #define VTBLK_MTX(_sc) &(_sc)->vtblk_mtx 205 #define VTBLK_LOCK_INIT(_sc, _name) \ 206 mtx_init(VTBLK_MTX((_sc)), (_name), \ 207 "VirtIO Block Lock", MTX_DEF) 208 #define VTBLK_LOCK(_sc) mtx_lock(VTBLK_MTX((_sc))) 209 #define VTBLK_UNLOCK(_sc) mtx_unlock(VTBLK_MTX((_sc))) 210 #define VTBLK_LOCK_DESTROY(_sc) mtx_destroy(VTBLK_MTX((_sc))) 211 #define VTBLK_LOCK_ASSERT(_sc) mtx_assert(VTBLK_MTX((_sc)), MA_OWNED) 212 #define VTBLK_LOCK_ASSERT_NOTOWNED(_sc) \ 213 mtx_assert(VTBLK_MTX((_sc)), MA_NOTOWNED) 214 215 #define VTBLK_DISK_NAME "vtbd" 216 #define VTBLK_QUIESCE_TIMEOUT (30 * hz) 217 218 /* 219 * Each block request uses at least two segments - one for the header 220 * and one for the status. 221 */ 222 #define VTBLK_MIN_SEGMENTS 2 223 224 static device_method_t vtblk_methods[] = { 225 /* Device methods. */ 226 DEVMETHOD(device_probe, vtblk_probe), 227 DEVMETHOD(device_attach, vtblk_attach), 228 DEVMETHOD(device_detach, vtblk_detach), 229 DEVMETHOD(device_suspend, vtblk_suspend), 230 DEVMETHOD(device_resume, vtblk_resume), 231 DEVMETHOD(device_shutdown, vtblk_shutdown), 232 233 /* VirtIO methods. */ 234 DEVMETHOD(virtio_config_change, vtblk_config_change), 235 236 DEVMETHOD_END 237 }; 238 239 static driver_t vtblk_driver = { 240 "vtblk", 241 vtblk_methods, 242 sizeof(struct vtblk_softc) 243 }; 244 static devclass_t vtblk_devclass; 245 246 DRIVER_MODULE(virtio_blk, virtio_mmio, vtblk_driver, vtblk_devclass, 247 vtblk_modevent, 0); 248 DRIVER_MODULE(virtio_blk, virtio_pci, vtblk_driver, vtblk_devclass, 249 vtblk_modevent, 0); 250 MODULE_VERSION(virtio_blk, 1); 251 MODULE_DEPEND(virtio_blk, virtio, 1, 1, 1); 252 253 static int 254 vtblk_modevent(module_t mod, int type, void *unused) 255 { 256 int error; 257 258 error = 0; 259 260 switch (type) { 261 case MOD_LOAD: 262 case MOD_QUIESCE: 263 case MOD_UNLOAD: 264 case MOD_SHUTDOWN: 265 break; 266 default: 267 error = EOPNOTSUPP; 268 break; 269 } 270 271 return (error); 272 } 273 274 static int 275 vtblk_probe(device_t dev) 276 { 277 278 if (virtio_get_device_type(dev) != VIRTIO_ID_BLOCK) 279 return (ENXIO); 280 281 device_set_desc(dev, "VirtIO Block Adapter"); 282 283 return (BUS_PROBE_DEFAULT); 284 } 285 286 static int 287 vtblk_attach(device_t dev) 288 { 289 struct vtblk_softc *sc; 290 struct virtio_blk_config blkcfg; 291 int error; 292 293 sc = device_get_softc(dev); 294 sc->vtblk_dev = dev; 295 296 VTBLK_LOCK_INIT(sc, device_get_nameunit(dev)); 297 298 bioq_init(&sc->vtblk_bioq); 299 TAILQ_INIT(&sc->vtblk_req_free); 300 TAILQ_INIT(&sc->vtblk_req_ready); 301 302 virtio_set_feature_desc(dev, vtblk_feature_desc); 303 vtblk_negotiate_features(sc); 304 305 if (virtio_with_feature(dev, VIRTIO_RING_F_INDIRECT_DESC)) 306 sc->vtblk_flags |= VTBLK_FLAG_INDIRECT; 307 if (virtio_with_feature(dev, VIRTIO_BLK_F_RO)) 308 sc->vtblk_flags |= VTBLK_FLAG_READONLY; 309 if (virtio_with_feature(dev, VIRTIO_BLK_F_BARRIER)) 310 sc->vtblk_flags |= VTBLK_FLAG_BARRIER; 311 if (virtio_with_feature(dev, VIRTIO_BLK_F_CONFIG_WCE)) 312 sc->vtblk_flags |= VTBLK_FLAG_WC_CONFIG; 313 314 vtblk_setup_sysctl(sc); 315 316 /* Get local copy of config. */ 317 vtblk_read_config(sc, &blkcfg); 318 319 /* 320 * With the current sglist(9) implementation, it is not easy 321 * for us to support a maximum segment size as adjacent 322 * segments are coalesced. For now, just make sure it's larger 323 * than the maximum supported transfer size. 324 */ 325 if (virtio_with_feature(dev, VIRTIO_BLK_F_SIZE_MAX)) { 326 if (blkcfg.size_max < MAXPHYS) { 327 error = ENOTSUP; 328 device_printf(dev, "host requires unsupported " 329 "maximum segment size feature\n"); 330 goto fail; 331 } 332 } 333 334 sc->vtblk_max_nsegs = vtblk_maximum_segments(sc, &blkcfg); 335 if (sc->vtblk_max_nsegs <= VTBLK_MIN_SEGMENTS) { 336 error = EINVAL; 337 device_printf(dev, "fewer than minimum number of segments " 338 "allowed: %d\n", sc->vtblk_max_nsegs); 339 goto fail; 340 } 341 342 sc->vtblk_sglist = sglist_alloc(sc->vtblk_max_nsegs, M_NOWAIT); 343 if (sc->vtblk_sglist == NULL) { 344 error = ENOMEM; 345 device_printf(dev, "cannot allocate sglist\n"); 346 goto fail; 347 } 348 349 error = vtblk_alloc_virtqueue(sc); 350 if (error) { 351 device_printf(dev, "cannot allocate virtqueue\n"); 352 goto fail; 353 } 354 355 error = vtblk_alloc_requests(sc); 356 if (error) { 357 device_printf(dev, "cannot preallocate requests\n"); 358 goto fail; 359 } 360 361 vtblk_alloc_disk(sc, &blkcfg); 362 363 error = virtio_setup_intr(dev, INTR_TYPE_BIO | INTR_ENTROPY); 364 if (error) { 365 device_printf(dev, "cannot setup virtqueue interrupt\n"); 366 goto fail; 367 } 368 369 vtblk_create_disk(sc); 370 371 virtqueue_enable_intr(sc->vtblk_vq); 372 373 fail: 374 if (error) 375 vtblk_detach(dev); 376 377 return (error); 378 } 379 380 static int 381 vtblk_detach(device_t dev) 382 { 383 struct vtblk_softc *sc; 384 385 sc = device_get_softc(dev); 386 387 VTBLK_LOCK(sc); 388 sc->vtblk_flags |= VTBLK_FLAG_DETACH; 389 if (device_is_attached(dev)) 390 vtblk_stop(sc); 391 VTBLK_UNLOCK(sc); 392 393 vtblk_drain(sc); 394 395 if (sc->vtblk_disk != NULL) { 396 disk_destroy(sc->vtblk_disk); 397 sc->vtblk_disk = NULL; 398 } 399 400 if (sc->vtblk_sglist != NULL) { 401 sglist_free(sc->vtblk_sglist); 402 sc->vtblk_sglist = NULL; 403 } 404 405 VTBLK_LOCK_DESTROY(sc); 406 407 return (0); 408 } 409 410 static int 411 vtblk_suspend(device_t dev) 412 { 413 struct vtblk_softc *sc; 414 int error; 415 416 sc = device_get_softc(dev); 417 418 VTBLK_LOCK(sc); 419 sc->vtblk_flags |= VTBLK_FLAG_SUSPEND; 420 /* XXX BMV: virtio_stop(), etc needed here? */ 421 error = vtblk_quiesce(sc); 422 if (error) 423 sc->vtblk_flags &= ~VTBLK_FLAG_SUSPEND; 424 VTBLK_UNLOCK(sc); 425 426 return (error); 427 } 428 429 static int 430 vtblk_resume(device_t dev) 431 { 432 struct vtblk_softc *sc; 433 434 sc = device_get_softc(dev); 435 436 VTBLK_LOCK(sc); 437 /* XXX BMV: virtio_reinit(), etc needed here? */ 438 sc->vtblk_flags &= ~VTBLK_FLAG_SUSPEND; 439 vtblk_startio(sc); 440 VTBLK_UNLOCK(sc); 441 442 return (0); 443 } 444 445 static int 446 vtblk_shutdown(device_t dev) 447 { 448 449 return (0); 450 } 451 452 static int 453 vtblk_config_change(device_t dev) 454 { 455 struct vtblk_softc *sc; 456 struct virtio_blk_config blkcfg; 457 uint64_t capacity; 458 459 sc = device_get_softc(dev); 460 461 vtblk_read_config(sc, &blkcfg); 462 463 /* Capacity is always in 512-byte units. */ 464 capacity = blkcfg.capacity * 512; 465 466 if (sc->vtblk_disk->d_mediasize != capacity) 467 vtblk_resize_disk(sc, capacity); 468 469 return (0); 470 } 471 472 static int 473 vtblk_open(struct disk *dp) 474 { 475 struct vtblk_softc *sc; 476 477 if ((sc = dp->d_drv1) == NULL) 478 return (ENXIO); 479 480 return (sc->vtblk_flags & VTBLK_FLAG_DETACH ? ENXIO : 0); 481 } 482 483 static int 484 vtblk_close(struct disk *dp) 485 { 486 struct vtblk_softc *sc; 487 488 if ((sc = dp->d_drv1) == NULL) 489 return (ENXIO); 490 491 return (0); 492 } 493 494 static int 495 vtblk_ioctl(struct disk *dp, u_long cmd, void *addr, int flag, 496 struct thread *td) 497 { 498 struct vtblk_softc *sc; 499 500 if ((sc = dp->d_drv1) == NULL) 501 return (ENXIO); 502 503 return (ENOTTY); 504 } 505 506 static int 507 vtblk_dump(void *arg, void *virtual, vm_offset_t physical, off_t offset, 508 size_t length) 509 { 510 struct disk *dp; 511 struct vtblk_softc *sc; 512 int error; 513 514 dp = arg; 515 516 if ((sc = dp->d_drv1) == NULL) 517 return (ENXIO); 518 519 VTBLK_LOCK(sc); 520 521 if ((sc->vtblk_flags & VTBLK_FLAG_DUMPING) == 0) { 522 vtblk_prepare_dump(sc); 523 sc->vtblk_flags |= VTBLK_FLAG_DUMPING; 524 } 525 526 if (length > 0) 527 error = vtblk_write_dump(sc, virtual, offset, length); 528 else if (virtual == NULL && offset == 0) 529 error = vtblk_flush_dump(sc); 530 else { 531 error = EINVAL; 532 sc->vtblk_flags &= ~VTBLK_FLAG_DUMPING; 533 } 534 535 VTBLK_UNLOCK(sc); 536 537 return (error); 538 } 539 540 static void 541 vtblk_strategy(struct bio *bp) 542 { 543 struct vtblk_softc *sc; 544 545 if ((sc = bp->bio_disk->d_drv1) == NULL) { 546 vtblk_finish_bio(bp, EINVAL); 547 return; 548 } 549 550 /* 551 * Fail any write if RO. Unfortunately, there does not seem to 552 * be a better way to report our readonly'ness to GEOM above. 553 */ 554 if (sc->vtblk_flags & VTBLK_FLAG_READONLY && 555 (bp->bio_cmd == BIO_WRITE || bp->bio_cmd == BIO_FLUSH)) { 556 vtblk_finish_bio(bp, EROFS); 557 return; 558 } 559 560 #ifdef INVARIANTS 561 /* 562 * Prevent read/write buffers spanning too many segments from 563 * getting into the queue. This should only trip if d_maxsize 564 * was incorrectly set. 565 */ 566 if (bp->bio_cmd == BIO_READ || bp->bio_cmd == BIO_WRITE) { 567 int nsegs, max_nsegs; 568 569 nsegs = sglist_count(bp->bio_data, bp->bio_bcount); 570 max_nsegs = sc->vtblk_max_nsegs - VTBLK_MIN_SEGMENTS; 571 572 KASSERT(nsegs <= max_nsegs, 573 ("%s: bio %p spanned too many segments: %d, max: %d", 574 __func__, bp, nsegs, max_nsegs)); 575 } 576 #endif 577 578 VTBLK_LOCK(sc); 579 if (sc->vtblk_flags & VTBLK_FLAG_DETACH) 580 vtblk_finish_bio(bp, ENXIO); 581 else { 582 bioq_insert_tail(&sc->vtblk_bioq, bp); 583 584 if ((sc->vtblk_flags & VTBLK_FLAG_SUSPEND) == 0) 585 vtblk_startio(sc); 586 } 587 VTBLK_UNLOCK(sc); 588 } 589 590 static void 591 vtblk_negotiate_features(struct vtblk_softc *sc) 592 { 593 device_t dev; 594 uint64_t features; 595 596 dev = sc->vtblk_dev; 597 features = VTBLK_FEATURES; 598 599 sc->vtblk_features = virtio_negotiate_features(dev, features); 600 } 601 602 static int 603 vtblk_maximum_segments(struct vtblk_softc *sc, 604 struct virtio_blk_config *blkcfg) 605 { 606 device_t dev; 607 int nsegs; 608 609 dev = sc->vtblk_dev; 610 nsegs = VTBLK_MIN_SEGMENTS; 611 612 if (virtio_with_feature(dev, VIRTIO_BLK_F_SEG_MAX)) { 613 nsegs += MIN(blkcfg->seg_max, MAXPHYS / PAGE_SIZE + 1); 614 if (sc->vtblk_flags & VTBLK_FLAG_INDIRECT) 615 nsegs = MIN(nsegs, VIRTIO_MAX_INDIRECT); 616 } else 617 nsegs += 1; 618 619 return (nsegs); 620 } 621 622 static int 623 vtblk_alloc_virtqueue(struct vtblk_softc *sc) 624 { 625 device_t dev; 626 struct vq_alloc_info vq_info; 627 628 dev = sc->vtblk_dev; 629 630 VQ_ALLOC_INFO_INIT(&vq_info, sc->vtblk_max_nsegs, 631 vtblk_vq_intr, sc, &sc->vtblk_vq, 632 "%s request", device_get_nameunit(dev)); 633 634 return (virtio_alloc_virtqueues(dev, 0, 1, &vq_info)); 635 } 636 637 static void 638 vtblk_resize_disk(struct vtblk_softc *sc, uint64_t new_capacity) 639 { 640 device_t dev; 641 struct disk *dp; 642 int error; 643 644 dev = sc->vtblk_dev; 645 dp = sc->vtblk_disk; 646 647 dp->d_mediasize = new_capacity; 648 if (bootverbose) { 649 device_printf(dev, "resized to %juMB (%ju %u byte sectors)\n", 650 (uintmax_t) dp->d_mediasize >> 20, 651 (uintmax_t) dp->d_mediasize / dp->d_sectorsize, 652 dp->d_sectorsize); 653 } 654 655 error = disk_resize(dp, M_NOWAIT); 656 if (error) { 657 device_printf(dev, 658 "disk_resize(9) failed, error: %d\n", error); 659 } 660 } 661 662 static void 663 vtblk_set_write_cache(struct vtblk_softc *sc, int wc) 664 { 665 666 /* Set either writeback (1) or writethrough (0) mode. */ 667 virtio_write_dev_config_1(sc->vtblk_dev, 668 offsetof(struct virtio_blk_config, writeback), wc); 669 } 670 671 static int 672 vtblk_write_cache_enabled(struct vtblk_softc *sc, 673 struct virtio_blk_config *blkcfg) 674 { 675 int wc; 676 677 if (sc->vtblk_flags & VTBLK_FLAG_WC_CONFIG) { 678 wc = vtblk_tunable_int(sc, "writecache_mode", 679 vtblk_writecache_mode); 680 if (wc >= 0 && wc < VTBLK_CACHE_MAX) 681 vtblk_set_write_cache(sc, wc); 682 else 683 wc = blkcfg->writeback; 684 } else 685 wc = virtio_with_feature(sc->vtblk_dev, VIRTIO_BLK_F_WCE); 686 687 return (wc); 688 } 689 690 static int 691 vtblk_write_cache_sysctl(SYSCTL_HANDLER_ARGS) 692 { 693 struct vtblk_softc *sc; 694 int wc, error; 695 696 sc = oidp->oid_arg1; 697 wc = sc->vtblk_write_cache; 698 699 error = sysctl_handle_int(oidp, &wc, 0, req); 700 if (error || req->newptr == NULL) 701 return (error); 702 if ((sc->vtblk_flags & VTBLK_FLAG_WC_CONFIG) == 0) 703 return (EPERM); 704 if (wc < 0 || wc >= VTBLK_CACHE_MAX) 705 return (EINVAL); 706 707 VTBLK_LOCK(sc); 708 sc->vtblk_write_cache = wc; 709 vtblk_set_write_cache(sc, sc->vtblk_write_cache); 710 VTBLK_UNLOCK(sc); 711 712 return (0); 713 } 714 715 static void 716 vtblk_alloc_disk(struct vtblk_softc *sc, struct virtio_blk_config *blkcfg) 717 { 718 device_t dev; 719 struct disk *dp; 720 721 dev = sc->vtblk_dev; 722 723 sc->vtblk_disk = dp = disk_alloc(); 724 dp->d_open = vtblk_open; 725 dp->d_close = vtblk_close; 726 dp->d_ioctl = vtblk_ioctl; 727 dp->d_strategy = vtblk_strategy; 728 dp->d_name = VTBLK_DISK_NAME; 729 dp->d_unit = device_get_unit(dev); 730 dp->d_drv1 = sc; 731 dp->d_flags = DISKFLAG_CANFLUSHCACHE | DISKFLAG_UNMAPPED_BIO; 732 dp->d_hba_vendor = virtio_get_vendor(dev); 733 dp->d_hba_device = virtio_get_device(dev); 734 dp->d_hba_subvendor = virtio_get_subvendor(dev); 735 dp->d_hba_subdevice = virtio_get_subdevice(dev); 736 737 if ((sc->vtblk_flags & VTBLK_FLAG_READONLY) == 0) 738 dp->d_dump = vtblk_dump; 739 740 /* Capacity is always in 512-byte units. */ 741 dp->d_mediasize = blkcfg->capacity * 512; 742 743 if (virtio_with_feature(dev, VIRTIO_BLK_F_BLK_SIZE)) 744 dp->d_sectorsize = blkcfg->blk_size; 745 else 746 dp->d_sectorsize = 512; 747 748 /* 749 * The VirtIO maximum I/O size is given in terms of segments. 750 * However, FreeBSD limits I/O size by logical buffer size, not 751 * by physically contiguous pages. Therefore, we have to assume 752 * no pages are contiguous. This may impose an artificially low 753 * maximum I/O size. But in practice, since QEMU advertises 128 754 * segments, this gives us a maximum IO size of 125 * PAGE_SIZE, 755 * which is typically greater than MAXPHYS. Eventually we should 756 * just advertise MAXPHYS and split buffers that are too big. 757 * 758 * Note we must subtract one additional segment in case of non 759 * page aligned buffers. 760 */ 761 dp->d_maxsize = (sc->vtblk_max_nsegs - VTBLK_MIN_SEGMENTS - 1) * 762 PAGE_SIZE; 763 if (dp->d_maxsize < PAGE_SIZE) 764 dp->d_maxsize = PAGE_SIZE; /* XXX */ 765 766 if (virtio_with_feature(dev, VIRTIO_BLK_F_GEOMETRY)) { 767 dp->d_fwsectors = blkcfg->geometry.sectors; 768 dp->d_fwheads = blkcfg->geometry.heads; 769 } 770 771 if (virtio_with_feature(dev, VIRTIO_BLK_F_TOPOLOGY)) { 772 dp->d_stripesize = dp->d_sectorsize * 773 (1 << blkcfg->topology.physical_block_exp); 774 dp->d_stripeoffset = (dp->d_stripesize - 775 blkcfg->topology.alignment_offset * dp->d_sectorsize) % 776 dp->d_stripesize; 777 } 778 779 if (vtblk_write_cache_enabled(sc, blkcfg) != 0) 780 sc->vtblk_write_cache = VTBLK_CACHE_WRITEBACK; 781 else 782 sc->vtblk_write_cache = VTBLK_CACHE_WRITETHROUGH; 783 } 784 785 static void 786 vtblk_create_disk(struct vtblk_softc *sc) 787 { 788 struct disk *dp; 789 790 dp = sc->vtblk_disk; 791 792 /* 793 * Retrieving the identification string must be done after 794 * the virtqueue interrupt is setup otherwise it will hang. 795 */ 796 vtblk_get_ident(sc); 797 798 device_printf(sc->vtblk_dev, "%juMB (%ju %u byte sectors)\n", 799 (uintmax_t) dp->d_mediasize >> 20, 800 (uintmax_t) dp->d_mediasize / dp->d_sectorsize, 801 dp->d_sectorsize); 802 803 disk_create(dp, DISK_VERSION); 804 } 805 806 static int 807 vtblk_quiesce(struct vtblk_softc *sc) 808 { 809 int error; 810 811 error = 0; 812 813 VTBLK_LOCK_ASSERT(sc); 814 815 while (!virtqueue_empty(sc->vtblk_vq)) { 816 if (mtx_sleep(&sc->vtblk_vq, VTBLK_MTX(sc), PRIBIO, "vtblkq", 817 VTBLK_QUIESCE_TIMEOUT) == EWOULDBLOCK) { 818 error = EBUSY; 819 break; 820 } 821 } 822 823 return (error); 824 } 825 826 static void 827 vtblk_startio(struct vtblk_softc *sc) 828 { 829 struct virtqueue *vq; 830 struct vtblk_request *req; 831 int enq; 832 833 vq = sc->vtblk_vq; 834 enq = 0; 835 836 VTBLK_LOCK_ASSERT(sc); 837 838 while (!virtqueue_full(vq)) { 839 if ((req = vtblk_dequeue_ready(sc)) == NULL) 840 req = vtblk_bio_request(sc); 841 if (req == NULL) 842 break; 843 844 if (vtblk_execute_request(sc, req) != 0) { 845 vtblk_enqueue_ready(sc, req); 846 break; 847 } 848 849 enq++; 850 } 851 852 if (enq > 0) 853 virtqueue_notify(vq); 854 } 855 856 static struct vtblk_request * 857 vtblk_bio_request(struct vtblk_softc *sc) 858 { 859 struct bio_queue_head *bioq; 860 struct vtblk_request *req; 861 struct bio *bp; 862 863 bioq = &sc->vtblk_bioq; 864 865 if (bioq_first(bioq) == NULL) 866 return (NULL); 867 868 req = vtblk_dequeue_request(sc); 869 if (req == NULL) 870 return (NULL); 871 872 bp = bioq_takefirst(bioq); 873 req->vbr_bp = bp; 874 req->vbr_ack = -1; 875 req->vbr_hdr.ioprio = 1; 876 877 switch (bp->bio_cmd) { 878 case BIO_FLUSH: 879 req->vbr_hdr.type = VIRTIO_BLK_T_FLUSH; 880 break; 881 case BIO_READ: 882 req->vbr_hdr.type = VIRTIO_BLK_T_IN; 883 req->vbr_hdr.sector = bp->bio_offset / 512; 884 break; 885 case BIO_WRITE: 886 req->vbr_hdr.type = VIRTIO_BLK_T_OUT; 887 req->vbr_hdr.sector = bp->bio_offset / 512; 888 break; 889 default: 890 panic("%s: bio with unhandled cmd: %d", __func__, bp->bio_cmd); 891 } 892 893 return (req); 894 } 895 896 static int 897 vtblk_execute_request(struct vtblk_softc *sc, struct vtblk_request *req) 898 { 899 struct virtqueue *vq; 900 struct sglist *sg; 901 struct bio *bp; 902 int ordered, readable, writable, error; 903 904 vq = sc->vtblk_vq; 905 sg = sc->vtblk_sglist; 906 bp = req->vbr_bp; 907 ordered = 0; 908 writable = 0; 909 910 VTBLK_LOCK_ASSERT(sc); 911 912 /* 913 * Wait until the ordered request completes before 914 * executing subsequent requests. 915 */ 916 if (sc->vtblk_req_ordered != NULL) 917 return (EBUSY); 918 919 if (bp->bio_flags & BIO_ORDERED) { 920 if ((sc->vtblk_flags & VTBLK_FLAG_BARRIER) == 0) { 921 /* 922 * This request will be executed once all 923 * the in-flight requests are completed. 924 */ 925 if (!virtqueue_empty(vq)) 926 return (EBUSY); 927 ordered = 1; 928 } else 929 req->vbr_hdr.type |= VIRTIO_BLK_T_BARRIER; 930 } 931 932 sglist_reset(sg); 933 sglist_append(sg, &req->vbr_hdr, sizeof(struct virtio_blk_outhdr)); 934 935 if (bp->bio_cmd == BIO_READ || bp->bio_cmd == BIO_WRITE) { 936 error = sglist_append_bio(sg, bp); 937 if (error || sg->sg_nseg == sg->sg_maxseg) { 938 panic("%s: data buffer too big bio:%p error:%d", 939 __func__, bp, error); 940 } 941 942 /* BIO_READ means the host writes into our buffer. */ 943 if (bp->bio_cmd == BIO_READ) 944 writable = sg->sg_nseg - 1; 945 } 946 947 writable++; 948 sglist_append(sg, &req->vbr_ack, sizeof(uint8_t)); 949 readable = sg->sg_nseg - writable; 950 951 error = virtqueue_enqueue(vq, req, sg, readable, writable); 952 if (error == 0 && ordered) 953 sc->vtblk_req_ordered = req; 954 955 return (error); 956 } 957 958 static void 959 vtblk_vq_intr(void *xsc) 960 { 961 struct vtblk_softc *sc; 962 struct virtqueue *vq; 963 964 sc = xsc; 965 vq = sc->vtblk_vq; 966 967 again: 968 VTBLK_LOCK(sc); 969 if (sc->vtblk_flags & VTBLK_FLAG_DETACH) { 970 VTBLK_UNLOCK(sc); 971 return; 972 } 973 974 vtblk_finish_completed(sc); 975 976 if ((sc->vtblk_flags & VTBLK_FLAG_SUSPEND) == 0) 977 vtblk_startio(sc); 978 else 979 wakeup(&sc->vtblk_vq); 980 981 if (virtqueue_enable_intr(vq) != 0) { 982 virtqueue_disable_intr(vq); 983 VTBLK_UNLOCK(sc); 984 goto again; 985 } 986 987 VTBLK_UNLOCK(sc); 988 } 989 990 static void 991 vtblk_stop(struct vtblk_softc *sc) 992 { 993 994 virtqueue_disable_intr(sc->vtblk_vq); 995 virtio_stop(sc->vtblk_dev); 996 } 997 998 #define VTBLK_GET_CONFIG(_dev, _feature, _field, _cfg) \ 999 if (virtio_with_feature(_dev, _feature)) { \ 1000 virtio_read_device_config(_dev, \ 1001 offsetof(struct virtio_blk_config, _field), \ 1002 &(_cfg)->_field, sizeof((_cfg)->_field)); \ 1003 } 1004 1005 static void 1006 vtblk_read_config(struct vtblk_softc *sc, struct virtio_blk_config *blkcfg) 1007 { 1008 device_t dev; 1009 1010 dev = sc->vtblk_dev; 1011 1012 bzero(blkcfg, sizeof(struct virtio_blk_config)); 1013 1014 /* The capacity is always available. */ 1015 virtio_read_device_config(dev, offsetof(struct virtio_blk_config, 1016 capacity), &blkcfg->capacity, sizeof(blkcfg->capacity)); 1017 1018 /* Read the configuration if the feature was negotiated. */ 1019 VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_SIZE_MAX, size_max, blkcfg); 1020 VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_SEG_MAX, seg_max, blkcfg); 1021 VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_GEOMETRY, geometry, blkcfg); 1022 VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_BLK_SIZE, blk_size, blkcfg); 1023 VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_TOPOLOGY, topology, blkcfg); 1024 VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_CONFIG_WCE, writeback, blkcfg); 1025 } 1026 1027 #undef VTBLK_GET_CONFIG 1028 1029 static void 1030 vtblk_get_ident(struct vtblk_softc *sc) 1031 { 1032 struct bio buf; 1033 struct disk *dp; 1034 struct vtblk_request *req; 1035 int len, error; 1036 1037 dp = sc->vtblk_disk; 1038 len = MIN(VIRTIO_BLK_ID_BYTES, DISK_IDENT_SIZE); 1039 1040 if (vtblk_tunable_int(sc, "no_ident", vtblk_no_ident) != 0) 1041 return; 1042 1043 req = vtblk_dequeue_request(sc); 1044 if (req == NULL) 1045 return; 1046 1047 req->vbr_ack = -1; 1048 req->vbr_hdr.type = VIRTIO_BLK_T_GET_ID; 1049 req->vbr_hdr.ioprio = 1; 1050 req->vbr_hdr.sector = 0; 1051 1052 req->vbr_bp = &buf; 1053 bzero(&buf, sizeof(struct bio)); 1054 1055 buf.bio_cmd = BIO_READ; 1056 buf.bio_data = dp->d_ident; 1057 buf.bio_bcount = len; 1058 1059 VTBLK_LOCK(sc); 1060 error = vtblk_poll_request(sc, req); 1061 VTBLK_UNLOCK(sc); 1062 1063 vtblk_enqueue_request(sc, req); 1064 1065 if (error) { 1066 device_printf(sc->vtblk_dev, 1067 "error getting device identifier: %d\n", error); 1068 } 1069 } 1070 1071 static void 1072 vtblk_prepare_dump(struct vtblk_softc *sc) 1073 { 1074 device_t dev; 1075 struct virtqueue *vq; 1076 1077 dev = sc->vtblk_dev; 1078 vq = sc->vtblk_vq; 1079 1080 vtblk_stop(sc); 1081 1082 /* 1083 * Drain all requests caught in-flight in the virtqueue, 1084 * skipping biodone(). When dumping, only one request is 1085 * outstanding at a time, and we just poll the virtqueue 1086 * for the response. 1087 */ 1088 vtblk_drain_vq(sc, 1); 1089 1090 if (virtio_reinit(dev, sc->vtblk_features) != 0) { 1091 panic("%s: cannot reinit VirtIO block device during dump", 1092 device_get_nameunit(dev)); 1093 } 1094 1095 virtqueue_disable_intr(vq); 1096 virtio_reinit_complete(dev); 1097 } 1098 1099 static int 1100 vtblk_write_dump(struct vtblk_softc *sc, void *virtual, off_t offset, 1101 size_t length) 1102 { 1103 struct bio buf; 1104 struct vtblk_request *req; 1105 1106 req = &sc->vtblk_dump_request; 1107 req->vbr_ack = -1; 1108 req->vbr_hdr.type = VIRTIO_BLK_T_OUT; 1109 req->vbr_hdr.ioprio = 1; 1110 req->vbr_hdr.sector = offset / 512; 1111 1112 req->vbr_bp = &buf; 1113 bzero(&buf, sizeof(struct bio)); 1114 1115 buf.bio_cmd = BIO_WRITE; 1116 buf.bio_data = virtual; 1117 buf.bio_bcount = length; 1118 1119 return (vtblk_poll_request(sc, req)); 1120 } 1121 1122 static int 1123 vtblk_flush_dump(struct vtblk_softc *sc) 1124 { 1125 struct bio buf; 1126 struct vtblk_request *req; 1127 1128 req = &sc->vtblk_dump_request; 1129 req->vbr_ack = -1; 1130 req->vbr_hdr.type = VIRTIO_BLK_T_FLUSH; 1131 req->vbr_hdr.ioprio = 1; 1132 req->vbr_hdr.sector = 0; 1133 1134 req->vbr_bp = &buf; 1135 bzero(&buf, sizeof(struct bio)); 1136 1137 buf.bio_cmd = BIO_FLUSH; 1138 1139 return (vtblk_poll_request(sc, req)); 1140 } 1141 1142 static int 1143 vtblk_poll_request(struct vtblk_softc *sc, struct vtblk_request *req) 1144 { 1145 struct virtqueue *vq; 1146 int error; 1147 1148 vq = sc->vtblk_vq; 1149 1150 if (!virtqueue_empty(vq)) 1151 return (EBUSY); 1152 1153 error = vtblk_execute_request(sc, req); 1154 if (error) 1155 return (error); 1156 1157 virtqueue_notify(vq); 1158 virtqueue_poll(vq, NULL); 1159 1160 error = vtblk_request_error(req); 1161 if (error && bootverbose) { 1162 device_printf(sc->vtblk_dev, 1163 "%s: IO error: %d\n", __func__, error); 1164 } 1165 1166 return (error); 1167 } 1168 1169 static void 1170 vtblk_finish_completed(struct vtblk_softc *sc) 1171 { 1172 struct vtblk_request *req; 1173 struct bio *bp; 1174 int error; 1175 1176 while ((req = virtqueue_dequeue(sc->vtblk_vq, NULL)) != NULL) { 1177 bp = req->vbr_bp; 1178 1179 if (sc->vtblk_req_ordered != NULL) { 1180 /* This should be the only outstanding request. */ 1181 MPASS(sc->vtblk_req_ordered == req); 1182 sc->vtblk_req_ordered = NULL; 1183 } 1184 1185 error = vtblk_request_error(req); 1186 if (error) 1187 disk_err(bp, "hard error", -1, 1); 1188 1189 vtblk_finish_bio(bp, error); 1190 vtblk_enqueue_request(sc, req); 1191 } 1192 } 1193 1194 static void 1195 vtblk_drain_vq(struct vtblk_softc *sc, int skip_done) 1196 { 1197 struct virtqueue *vq; 1198 struct vtblk_request *req; 1199 int last; 1200 1201 vq = sc->vtblk_vq; 1202 last = 0; 1203 1204 while ((req = virtqueue_drain(vq, &last)) != NULL) { 1205 if (!skip_done) 1206 vtblk_finish_bio(req->vbr_bp, ENXIO); 1207 1208 vtblk_enqueue_request(sc, req); 1209 } 1210 1211 sc->vtblk_req_ordered = NULL; 1212 KASSERT(virtqueue_empty(vq), ("virtqueue not empty")); 1213 } 1214 1215 static void 1216 vtblk_drain(struct vtblk_softc *sc) 1217 { 1218 struct bio_queue_head *bioq; 1219 struct vtblk_request *req; 1220 struct bio *bp; 1221 1222 bioq = &sc->vtblk_bioq; 1223 1224 if (sc->vtblk_vq != NULL) { 1225 vtblk_finish_completed(sc); 1226 vtblk_drain_vq(sc, 0); 1227 } 1228 1229 while ((req = vtblk_dequeue_ready(sc)) != NULL) { 1230 vtblk_finish_bio(req->vbr_bp, ENXIO); 1231 vtblk_enqueue_request(sc, req); 1232 } 1233 1234 while (bioq_first(bioq) != NULL) { 1235 bp = bioq_takefirst(bioq); 1236 vtblk_finish_bio(bp, ENXIO); 1237 } 1238 1239 vtblk_free_requests(sc); 1240 } 1241 1242 #ifdef INVARIANTS 1243 static void 1244 vtblk_request_invariants(struct vtblk_request *req) 1245 { 1246 int hdr_nsegs, ack_nsegs; 1247 1248 hdr_nsegs = sglist_count(&req->vbr_hdr, sizeof(req->vbr_hdr)); 1249 ack_nsegs = sglist_count(&req->vbr_ack, sizeof(req->vbr_ack)); 1250 1251 KASSERT(hdr_nsegs == 1, ("request header crossed page boundary")); 1252 KASSERT(ack_nsegs == 1, ("request ack crossed page boundary")); 1253 } 1254 #endif 1255 1256 static int 1257 vtblk_alloc_requests(struct vtblk_softc *sc) 1258 { 1259 struct vtblk_request *req; 1260 int i, nreqs; 1261 1262 nreqs = virtqueue_size(sc->vtblk_vq); 1263 1264 /* 1265 * Preallocate sufficient requests to keep the virtqueue full. Each 1266 * request consumes VTBLK_MIN_SEGMENTS or more descriptors so reduce 1267 * the number allocated when indirect descriptors are not available. 1268 */ 1269 if ((sc->vtblk_flags & VTBLK_FLAG_INDIRECT) == 0) 1270 nreqs /= VTBLK_MIN_SEGMENTS; 1271 1272 for (i = 0; i < nreqs; i++) { 1273 req = malloc(sizeof(struct vtblk_request), M_DEVBUF, M_NOWAIT); 1274 if (req == NULL) 1275 return (ENOMEM); 1276 1277 #ifdef INVARIANTS 1278 vtblk_request_invariants(req); 1279 #endif 1280 1281 sc->vtblk_request_count++; 1282 vtblk_enqueue_request(sc, req); 1283 } 1284 1285 return (0); 1286 } 1287 1288 static void 1289 vtblk_free_requests(struct vtblk_softc *sc) 1290 { 1291 struct vtblk_request *req; 1292 1293 KASSERT(TAILQ_EMPTY(&sc->vtblk_req_ready), 1294 ("%s: ready requests left on queue", __func__)); 1295 1296 while ((req = vtblk_dequeue_request(sc)) != NULL) { 1297 sc->vtblk_request_count--; 1298 free(req, M_DEVBUF); 1299 } 1300 1301 KASSERT(sc->vtblk_request_count == 0, 1302 ("%s: leaked %d requests", __func__, sc->vtblk_request_count)); 1303 } 1304 1305 static struct vtblk_request * 1306 vtblk_dequeue_request(struct vtblk_softc *sc) 1307 { 1308 struct vtblk_request *req; 1309 1310 req = TAILQ_FIRST(&sc->vtblk_req_free); 1311 if (req != NULL) 1312 TAILQ_REMOVE(&sc->vtblk_req_free, req, vbr_link); 1313 1314 return (req); 1315 } 1316 1317 static void 1318 vtblk_enqueue_request(struct vtblk_softc *sc, struct vtblk_request *req) 1319 { 1320 1321 bzero(req, sizeof(struct vtblk_request)); 1322 TAILQ_INSERT_HEAD(&sc->vtblk_req_free, req, vbr_link); 1323 } 1324 1325 static struct vtblk_request * 1326 vtblk_dequeue_ready(struct vtblk_softc *sc) 1327 { 1328 struct vtblk_request *req; 1329 1330 req = TAILQ_FIRST(&sc->vtblk_req_ready); 1331 if (req != NULL) 1332 TAILQ_REMOVE(&sc->vtblk_req_ready, req, vbr_link); 1333 1334 return (req); 1335 } 1336 1337 static void 1338 vtblk_enqueue_ready(struct vtblk_softc *sc, struct vtblk_request *req) 1339 { 1340 1341 TAILQ_INSERT_HEAD(&sc->vtblk_req_ready, req, vbr_link); 1342 } 1343 1344 static int 1345 vtblk_request_error(struct vtblk_request *req) 1346 { 1347 int error; 1348 1349 switch (req->vbr_ack) { 1350 case VIRTIO_BLK_S_OK: 1351 error = 0; 1352 break; 1353 case VIRTIO_BLK_S_UNSUPP: 1354 error = ENOTSUP; 1355 break; 1356 default: 1357 error = EIO; 1358 break; 1359 } 1360 1361 return (error); 1362 } 1363 1364 static void 1365 vtblk_finish_bio(struct bio *bp, int error) 1366 { 1367 1368 if (error) { 1369 bp->bio_resid = bp->bio_bcount; 1370 bp->bio_error = error; 1371 bp->bio_flags |= BIO_ERROR; 1372 } 1373 1374 biodone(bp); 1375 } 1376 1377 static void 1378 vtblk_setup_sysctl(struct vtblk_softc *sc) 1379 { 1380 device_t dev; 1381 struct sysctl_ctx_list *ctx; 1382 struct sysctl_oid *tree; 1383 struct sysctl_oid_list *child; 1384 1385 dev = sc->vtblk_dev; 1386 ctx = device_get_sysctl_ctx(dev); 1387 tree = device_get_sysctl_tree(dev); 1388 child = SYSCTL_CHILDREN(tree); 1389 1390 SYSCTL_ADD_PROC(ctx, child, OID_AUTO, "writecache_mode", 1391 CTLTYPE_INT | CTLFLAG_RW, sc, 0, vtblk_write_cache_sysctl, 1392 "I", "Write cache mode (writethrough (0) or writeback (1))"); 1393 } 1394 1395 static int 1396 vtblk_tunable_int(struct vtblk_softc *sc, const char *knob, int def) 1397 { 1398 char path[64]; 1399 1400 snprintf(path, sizeof(path), 1401 "hw.vtblk.%d.%s", device_get_unit(sc->vtblk_dev), knob); 1402 TUNABLE_INT_FETCH(path, &def); 1403 1404 return (def); 1405 } 1406