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