1 /* 2 * XenBSD block device driver 3 * 4 * Copyright (c) 2010-2013 Spectra Logic Corporation 5 * Copyright (c) 2009 Scott Long, Yahoo! 6 * Copyright (c) 2009 Frank Suchomel, Citrix 7 * Copyright (c) 2009 Doug F. Rabson, Citrix 8 * Copyright (c) 2005 Kip Macy 9 * Copyright (c) 2003-2004, Keir Fraser & Steve Hand 10 * Modifications by Mark A. Williamson are (c) Intel Research Cambridge 11 * 12 * 13 * Permission is hereby granted, free of charge, to any person obtaining a copy 14 * of this software and associated documentation files (the "Software"), to 15 * deal in the Software without restriction, including without limitation the 16 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or 17 * sell copies of the Software, and to permit persons to whom the Software is 18 * furnished to do so, subject to the following conditions: 19 * 20 * The above copyright notice and this permission notice shall be included in 21 * all copies or substantial portions of the Software. 22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 23 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 24 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 25 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 26 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 27 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 28 * DEALINGS IN THE SOFTWARE. 29 */ 30 31 #include <sys/cdefs.h> 32 __FBSDID("$FreeBSD$"); 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/malloc.h> 37 #include <sys/kernel.h> 38 #include <vm/vm.h> 39 #include <vm/pmap.h> 40 41 #include <sys/bio.h> 42 #include <sys/bus.h> 43 #include <sys/conf.h> 44 #include <sys/module.h> 45 #include <sys/sysctl.h> 46 47 #include <machine/bus.h> 48 #include <sys/rman.h> 49 #include <machine/resource.h> 50 #include <machine/intr_machdep.h> 51 #include <machine/vmparam.h> 52 #include <sys/bus_dma.h> 53 54 #include <xen/xen-os.h> 55 #include <xen/hypervisor.h> 56 #include <xen/xen_intr.h> 57 #include <xen/gnttab.h> 58 #include <xen/interface/grant_table.h> 59 #include <xen/interface/io/protocols.h> 60 #include <xen/xenbus/xenbusvar.h> 61 62 #include <machine/_inttypes.h> 63 #include <machine/xen/xenvar.h> 64 65 #include <geom/geom_disk.h> 66 67 #include <dev/xen/blkfront/block.h> 68 69 #include "xenbus_if.h" 70 71 /*--------------------------- Forward Declarations ---------------------------*/ 72 static void xbd_closing(device_t); 73 static void xbd_startio(struct xbd_softc *sc); 74 75 /*---------------------------------- Macros ----------------------------------*/ 76 #if 0 77 #define DPRINTK(fmt, args...) printf("[XEN] %s:%d: " fmt ".\n", __func__, __LINE__, ##args) 78 #else 79 #define DPRINTK(fmt, args...) 80 #endif 81 82 #define XBD_SECTOR_SHFT 9 83 84 /*---------------------------- Global Static Data ----------------------------*/ 85 static MALLOC_DEFINE(M_XENBLOCKFRONT, "xbd", "Xen Block Front driver data"); 86 87 /*---------------------------- Command Processing ----------------------------*/ 88 static void 89 xbd_freeze(struct xbd_softc *sc, xbd_flag_t xbd_flag) 90 { 91 if (xbd_flag != XBDF_NONE && (sc->xbd_flags & xbd_flag) != 0) 92 return; 93 94 sc->xbd_flags |= xbd_flag; 95 sc->xbd_qfrozen_cnt++; 96 } 97 98 static void 99 xbd_thaw(struct xbd_softc *sc, xbd_flag_t xbd_flag) 100 { 101 if (xbd_flag != XBDF_NONE && (sc->xbd_flags & xbd_flag) == 0) 102 return; 103 104 if (sc->xbd_qfrozen_cnt == 0) 105 panic("%s: Thaw with flag 0x%x while not frozen.", 106 __func__, xbd_flag); 107 108 sc->xbd_flags &= ~xbd_flag; 109 sc->xbd_qfrozen_cnt--; 110 } 111 112 static void 113 xbd_cm_freeze(struct xbd_softc *sc, struct xbd_command *cm, xbdc_flag_t cm_flag) 114 { 115 if ((cm->cm_flags & XBDCF_FROZEN) != 0) 116 return; 117 118 cm->cm_flags |= XBDCF_FROZEN|cm_flag; 119 xbd_freeze(sc, XBDF_NONE); 120 } 121 122 static void 123 xbd_cm_thaw(struct xbd_softc *sc, struct xbd_command *cm) 124 { 125 if ((cm->cm_flags & XBDCF_FROZEN) == 0) 126 return; 127 128 cm->cm_flags &= ~XBDCF_FROZEN; 129 xbd_thaw(sc, XBDF_NONE); 130 } 131 132 static inline void 133 xbd_flush_requests(struct xbd_softc *sc) 134 { 135 int notify; 136 137 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&sc->xbd_ring, notify); 138 139 if (notify) 140 xen_intr_signal(sc->xen_intr_handle); 141 } 142 143 static void 144 xbd_free_command(struct xbd_command *cm) 145 { 146 147 KASSERT((cm->cm_flags & XBDCF_Q_MASK) == XBD_Q_NONE, 148 ("Freeing command that is still on queue %d.", 149 cm->cm_flags & XBDCF_Q_MASK)); 150 151 cm->cm_flags = XBDCF_INITIALIZER; 152 cm->cm_bp = NULL; 153 cm->cm_complete = NULL; 154 xbd_enqueue_cm(cm, XBD_Q_FREE); 155 xbd_thaw(cm->cm_sc, XBDF_CM_SHORTAGE); 156 } 157 158 static void 159 xbd_queue_cb(void *arg, bus_dma_segment_t *segs, int nsegs, int error) 160 { 161 struct xbd_softc *sc; 162 struct xbd_command *cm; 163 blkif_request_t *ring_req; 164 struct blkif_request_segment *sg; 165 struct blkif_request_segment *last_block_sg; 166 grant_ref_t *sg_ref; 167 vm_paddr_t buffer_ma; 168 uint64_t fsect, lsect; 169 int ref; 170 int op; 171 int block_segs; 172 173 cm = arg; 174 sc = cm->cm_sc; 175 176 if (error) { 177 cm->cm_bp->bio_error = EIO; 178 biodone(cm->cm_bp); 179 xbd_free_command(cm); 180 return; 181 } 182 183 /* Fill out a communications ring structure. */ 184 ring_req = RING_GET_REQUEST(&sc->xbd_ring, sc->xbd_ring.req_prod_pvt); 185 sc->xbd_ring.req_prod_pvt++; 186 ring_req->id = cm->cm_id; 187 ring_req->operation = cm->cm_operation; 188 ring_req->sector_number = cm->cm_sector_number; 189 ring_req->handle = (blkif_vdev_t)(uintptr_t)sc->xbd_disk; 190 ring_req->nr_segments = nsegs; 191 cm->cm_nseg = nsegs; 192 193 block_segs = MIN(nsegs, BLKIF_MAX_SEGMENTS_PER_REQUEST); 194 sg = ring_req->seg; 195 last_block_sg = sg + block_segs; 196 sg_ref = cm->cm_sg_refs; 197 198 while (sg < last_block_sg) { 199 buffer_ma = segs->ds_addr; 200 fsect = (buffer_ma & PAGE_MASK) >> XBD_SECTOR_SHFT; 201 lsect = fsect + (segs->ds_len >> XBD_SECTOR_SHFT) - 1; 202 203 KASSERT(lsect <= 7, ("XEN disk driver data cannot " 204 "cross a page boundary")); 205 206 /* install a grant reference. */ 207 ref = gnttab_claim_grant_reference(&cm->cm_gref_head); 208 209 /* 210 * GNTTAB_LIST_END == 0xffffffff, but it is private 211 * to gnttab.c. 212 */ 213 KASSERT(ref != ~0, ("grant_reference failed")); 214 215 gnttab_grant_foreign_access_ref( 216 ref, 217 xenbus_get_otherend_id(sc->xbd_dev), 218 buffer_ma >> PAGE_SHIFT, 219 ring_req->operation == BLKIF_OP_WRITE); 220 221 *sg_ref = ref; 222 *sg = (struct blkif_request_segment) { 223 .gref = ref, 224 .first_sect = fsect, 225 .last_sect = lsect 226 }; 227 sg++; 228 sg_ref++; 229 segs++; 230 nsegs--; 231 } 232 233 if (cm->cm_operation == BLKIF_OP_READ) 234 op = BUS_DMASYNC_PREREAD; 235 else if (cm->cm_operation == BLKIF_OP_WRITE) 236 op = BUS_DMASYNC_PREWRITE; 237 else 238 op = 0; 239 bus_dmamap_sync(sc->xbd_io_dmat, cm->cm_map, op); 240 241 gnttab_free_grant_references(cm->cm_gref_head); 242 243 xbd_enqueue_cm(cm, XBD_Q_BUSY); 244 245 /* 246 * If bus dma had to asynchronously call us back to dispatch 247 * this command, we are no longer executing in the context of 248 * xbd_startio(). Thus we cannot rely on xbd_startio()'s call to 249 * xbd_flush_requests() to publish this command to the backend 250 * along with any other commands that it could batch. 251 */ 252 if ((cm->cm_flags & XBDCF_ASYNC_MAPPING) != 0) 253 xbd_flush_requests(sc); 254 255 return; 256 } 257 258 static int 259 xbd_queue_request(struct xbd_softc *sc, struct xbd_command *cm) 260 { 261 int error; 262 263 error = bus_dmamap_load(sc->xbd_io_dmat, cm->cm_map, cm->cm_data, 264 cm->cm_datalen, xbd_queue_cb, cm, 0); 265 if (error == EINPROGRESS) { 266 /* 267 * Maintain queuing order by freezing the queue. The next 268 * command may not require as many resources as the command 269 * we just attempted to map, so we can't rely on bus dma 270 * blocking for it too. 271 */ 272 xbd_cm_freeze(sc, cm, XBDCF_ASYNC_MAPPING); 273 return (0); 274 } 275 276 return (error); 277 } 278 279 static void 280 xbd_restart_queue_callback(void *arg) 281 { 282 struct xbd_softc *sc = arg; 283 284 mtx_lock(&sc->xbd_io_lock); 285 286 xbd_thaw(sc, XBDF_GNT_SHORTAGE); 287 288 xbd_startio(sc); 289 290 mtx_unlock(&sc->xbd_io_lock); 291 } 292 293 static struct xbd_command * 294 xbd_bio_command(struct xbd_softc *sc) 295 { 296 struct xbd_command *cm; 297 struct bio *bp; 298 299 if (__predict_false(sc->xbd_state != XBD_STATE_CONNECTED)) 300 return (NULL); 301 302 bp = xbd_dequeue_bio(sc); 303 if (bp == NULL) 304 return (NULL); 305 306 if ((cm = xbd_dequeue_cm(sc, XBD_Q_FREE)) == NULL) { 307 xbd_freeze(sc, XBDF_CM_SHORTAGE); 308 xbd_requeue_bio(sc, bp); 309 return (NULL); 310 } 311 312 if (gnttab_alloc_grant_references(sc->xbd_max_request_segments, 313 &cm->cm_gref_head) != 0) { 314 gnttab_request_free_callback(&sc->xbd_callback, 315 xbd_restart_queue_callback, sc, 316 sc->xbd_max_request_segments); 317 xbd_freeze(sc, XBDF_GNT_SHORTAGE); 318 xbd_requeue_bio(sc, bp); 319 xbd_enqueue_cm(cm, XBD_Q_FREE); 320 return (NULL); 321 } 322 323 cm->cm_bp = bp; 324 cm->cm_data = bp->bio_data; 325 cm->cm_datalen = bp->bio_bcount; 326 cm->cm_sector_number = (blkif_sector_t)bp->bio_pblkno; 327 328 switch (bp->bio_cmd) { 329 case BIO_READ: 330 cm->cm_operation = BLKIF_OP_READ; 331 break; 332 case BIO_WRITE: 333 cm->cm_operation = BLKIF_OP_WRITE; 334 if ((bp->bio_flags & BIO_ORDERED) != 0) { 335 if ((sc->xbd_flags & XBDF_BARRIER) != 0) { 336 cm->cm_operation = BLKIF_OP_WRITE_BARRIER; 337 } else { 338 /* 339 * Single step this command. 340 */ 341 cm->cm_flags |= XBDCF_Q_FREEZE; 342 if (xbd_queue_length(sc, XBD_Q_BUSY) != 0) { 343 /* 344 * Wait for in-flight requests to 345 * finish. 346 */ 347 xbd_freeze(sc, XBDF_WAIT_IDLE); 348 xbd_requeue_cm(cm, XBD_Q_READY); 349 return (NULL); 350 } 351 } 352 } 353 break; 354 case BIO_FLUSH: 355 if ((sc->xbd_flags & XBDF_FLUSH) != 0) 356 cm->cm_operation = BLKIF_OP_FLUSH_DISKCACHE; 357 else if ((sc->xbd_flags & XBDF_BARRIER) != 0) 358 cm->cm_operation = BLKIF_OP_WRITE_BARRIER; 359 else 360 panic("flush request, but no flush support available"); 361 break; 362 default: 363 panic("unknown bio command %d", bp->bio_cmd); 364 } 365 366 return (cm); 367 } 368 369 /* 370 * Dequeue buffers and place them in the shared communication ring. 371 * Return when no more requests can be accepted or all buffers have 372 * been queued. 373 * 374 * Signal XEN once the ring has been filled out. 375 */ 376 static void 377 xbd_startio(struct xbd_softc *sc) 378 { 379 struct xbd_command *cm; 380 int error, queued = 0; 381 382 mtx_assert(&sc->xbd_io_lock, MA_OWNED); 383 384 if (sc->xbd_state != XBD_STATE_CONNECTED) 385 return; 386 387 while (!RING_FULL(&sc->xbd_ring)) { 388 389 if (sc->xbd_qfrozen_cnt != 0) 390 break; 391 392 cm = xbd_dequeue_cm(sc, XBD_Q_READY); 393 394 if (cm == NULL) 395 cm = xbd_bio_command(sc); 396 397 if (cm == NULL) 398 break; 399 400 if ((cm->cm_flags & XBDCF_Q_FREEZE) != 0) { 401 /* 402 * Single step command. Future work is 403 * held off until this command completes. 404 */ 405 xbd_cm_freeze(sc, cm, XBDCF_Q_FREEZE); 406 } 407 408 if ((error = xbd_queue_request(sc, cm)) != 0) { 409 printf("xbd_queue_request returned %d\n", error); 410 break; 411 } 412 queued++; 413 } 414 415 if (queued != 0) 416 xbd_flush_requests(sc); 417 } 418 419 static void 420 xbd_bio_complete(struct xbd_softc *sc, struct xbd_command *cm) 421 { 422 struct bio *bp; 423 424 bp = cm->cm_bp; 425 426 if (__predict_false(cm->cm_status != BLKIF_RSP_OKAY)) { 427 disk_err(bp, "disk error" , -1, 0); 428 printf(" status: %x\n", cm->cm_status); 429 bp->bio_flags |= BIO_ERROR; 430 } 431 432 if (bp->bio_flags & BIO_ERROR) 433 bp->bio_error = EIO; 434 else 435 bp->bio_resid = 0; 436 437 xbd_free_command(cm); 438 biodone(bp); 439 } 440 441 static void 442 xbd_int(void *xsc) 443 { 444 struct xbd_softc *sc = xsc; 445 struct xbd_command *cm; 446 blkif_response_t *bret; 447 RING_IDX i, rp; 448 int op; 449 450 mtx_lock(&sc->xbd_io_lock); 451 452 if (__predict_false(sc->xbd_state == XBD_STATE_DISCONNECTED)) { 453 mtx_unlock(&sc->xbd_io_lock); 454 return; 455 } 456 457 again: 458 rp = sc->xbd_ring.sring->rsp_prod; 459 rmb(); /* Ensure we see queued responses up to 'rp'. */ 460 461 for (i = sc->xbd_ring.rsp_cons; i != rp;) { 462 bret = RING_GET_RESPONSE(&sc->xbd_ring, i); 463 cm = &sc->xbd_shadow[bret->id]; 464 465 xbd_remove_cm(cm, XBD_Q_BUSY); 466 gnttab_end_foreign_access_references(cm->cm_nseg, 467 cm->cm_sg_refs); 468 i++; 469 470 if (cm->cm_operation == BLKIF_OP_READ) 471 op = BUS_DMASYNC_POSTREAD; 472 else if (cm->cm_operation == BLKIF_OP_WRITE || 473 cm->cm_operation == BLKIF_OP_WRITE_BARRIER) 474 op = BUS_DMASYNC_POSTWRITE; 475 else 476 op = 0; 477 bus_dmamap_sync(sc->xbd_io_dmat, cm->cm_map, op); 478 bus_dmamap_unload(sc->xbd_io_dmat, cm->cm_map); 479 480 /* 481 * Release any hold this command has on future command 482 * dispatch. 483 */ 484 xbd_cm_thaw(sc, cm); 485 486 /* 487 * Directly call the i/o complete routine to save an 488 * an indirection in the common case. 489 */ 490 cm->cm_status = bret->status; 491 if (cm->cm_bp) 492 xbd_bio_complete(sc, cm); 493 else if (cm->cm_complete != NULL) 494 cm->cm_complete(cm); 495 else 496 xbd_free_command(cm); 497 } 498 499 sc->xbd_ring.rsp_cons = i; 500 501 if (i != sc->xbd_ring.req_prod_pvt) { 502 int more_to_do; 503 RING_FINAL_CHECK_FOR_RESPONSES(&sc->xbd_ring, more_to_do); 504 if (more_to_do) 505 goto again; 506 } else { 507 sc->xbd_ring.sring->rsp_event = i + 1; 508 } 509 510 if (xbd_queue_length(sc, XBD_Q_BUSY) == 0) 511 xbd_thaw(sc, XBDF_WAIT_IDLE); 512 513 xbd_startio(sc); 514 515 if (__predict_false(sc->xbd_state == XBD_STATE_SUSPENDED)) 516 wakeup(&sc->xbd_cm_q[XBD_Q_BUSY]); 517 518 mtx_unlock(&sc->xbd_io_lock); 519 } 520 521 /*------------------------------- Dump Support -------------------------------*/ 522 /** 523 * Quiesce the disk writes for a dump file before allowing the next buffer. 524 */ 525 static void 526 xbd_quiesce(struct xbd_softc *sc) 527 { 528 int mtd; 529 530 // While there are outstanding requests 531 while (xbd_queue_length(sc, XBD_Q_BUSY) != 0) { 532 RING_FINAL_CHECK_FOR_RESPONSES(&sc->xbd_ring, mtd); 533 if (mtd) { 534 /* Recieved request completions, update queue. */ 535 xbd_int(sc); 536 } 537 if (xbd_queue_length(sc, XBD_Q_BUSY) != 0) { 538 /* 539 * Still pending requests, wait for the disk i/o 540 * to complete. 541 */ 542 HYPERVISOR_yield(); 543 } 544 } 545 } 546 547 /* Kernel dump function for a paravirtualized disk device */ 548 static void 549 xbd_dump_complete(struct xbd_command *cm) 550 { 551 552 xbd_enqueue_cm(cm, XBD_Q_COMPLETE); 553 } 554 555 static int 556 xbd_dump(void *arg, void *virtual, vm_offset_t physical, off_t offset, 557 size_t length) 558 { 559 struct disk *dp = arg; 560 struct xbd_softc *sc = dp->d_drv1; 561 struct xbd_command *cm; 562 size_t chunk; 563 int sbp; 564 int rc = 0; 565 566 if (length <= 0) 567 return (rc); 568 569 xbd_quiesce(sc); /* All quiet on the western front. */ 570 571 /* 572 * If this lock is held, then this module is failing, and a 573 * successful kernel dump is highly unlikely anyway. 574 */ 575 mtx_lock(&sc->xbd_io_lock); 576 577 /* Split the 64KB block as needed */ 578 for (sbp=0; length > 0; sbp++) { 579 cm = xbd_dequeue_cm(sc, XBD_Q_FREE); 580 if (cm == NULL) { 581 mtx_unlock(&sc->xbd_io_lock); 582 device_printf(sc->xbd_dev, "dump: no more commands?\n"); 583 return (EBUSY); 584 } 585 586 if (gnttab_alloc_grant_references(sc->xbd_max_request_segments, 587 &cm->cm_gref_head) != 0) { 588 xbd_free_command(cm); 589 mtx_unlock(&sc->xbd_io_lock); 590 device_printf(sc->xbd_dev, "no more grant allocs?\n"); 591 return (EBUSY); 592 } 593 594 chunk = length > sc->xbd_max_request_size ? 595 sc->xbd_max_request_size : length; 596 cm->cm_data = virtual; 597 cm->cm_datalen = chunk; 598 cm->cm_operation = BLKIF_OP_WRITE; 599 cm->cm_sector_number = offset / dp->d_sectorsize; 600 cm->cm_complete = xbd_dump_complete; 601 602 xbd_enqueue_cm(cm, XBD_Q_READY); 603 604 length -= chunk; 605 offset += chunk; 606 virtual = (char *) virtual + chunk; 607 } 608 609 /* Tell DOM0 to do the I/O */ 610 xbd_startio(sc); 611 mtx_unlock(&sc->xbd_io_lock); 612 613 /* Poll for the completion. */ 614 xbd_quiesce(sc); /* All quite on the eastern front */ 615 616 /* If there were any errors, bail out... */ 617 while ((cm = xbd_dequeue_cm(sc, XBD_Q_COMPLETE)) != NULL) { 618 if (cm->cm_status != BLKIF_RSP_OKAY) { 619 device_printf(sc->xbd_dev, 620 "Dump I/O failed at sector %jd\n", 621 cm->cm_sector_number); 622 rc = EIO; 623 } 624 xbd_free_command(cm); 625 } 626 627 return (rc); 628 } 629 630 /*----------------------------- Disk Entrypoints -----------------------------*/ 631 static int 632 xbd_open(struct disk *dp) 633 { 634 struct xbd_softc *sc = dp->d_drv1; 635 636 if (sc == NULL) { 637 printf("xb%d: not found", sc->xbd_unit); 638 return (ENXIO); 639 } 640 641 sc->xbd_flags |= XBDF_OPEN; 642 sc->xbd_users++; 643 return (0); 644 } 645 646 static int 647 xbd_close(struct disk *dp) 648 { 649 struct xbd_softc *sc = dp->d_drv1; 650 651 if (sc == NULL) 652 return (ENXIO); 653 sc->xbd_flags &= ~XBDF_OPEN; 654 if (--(sc->xbd_users) == 0) { 655 /* 656 * Check whether we have been instructed to close. We will 657 * have ignored this request initially, as the device was 658 * still mounted. 659 */ 660 if (xenbus_get_otherend_state(sc->xbd_dev) == 661 XenbusStateClosing) 662 xbd_closing(sc->xbd_dev); 663 } 664 return (0); 665 } 666 667 static int 668 xbd_ioctl(struct disk *dp, u_long cmd, void *addr, int flag, struct thread *td) 669 { 670 struct xbd_softc *sc = dp->d_drv1; 671 672 if (sc == NULL) 673 return (ENXIO); 674 675 return (ENOTTY); 676 } 677 678 /* 679 * Read/write routine for a buffer. Finds the proper unit, place it on 680 * the sortq and kick the controller. 681 */ 682 static void 683 xbd_strategy(struct bio *bp) 684 { 685 struct xbd_softc *sc = bp->bio_disk->d_drv1; 686 687 /* bogus disk? */ 688 if (sc == NULL) { 689 bp->bio_error = EINVAL; 690 bp->bio_flags |= BIO_ERROR; 691 bp->bio_resid = bp->bio_bcount; 692 biodone(bp); 693 return; 694 } 695 696 /* 697 * Place it in the queue of disk activities for this disk 698 */ 699 mtx_lock(&sc->xbd_io_lock); 700 701 xbd_enqueue_bio(sc, bp); 702 xbd_startio(sc); 703 704 mtx_unlock(&sc->xbd_io_lock); 705 return; 706 } 707 708 /*------------------------------ Ring Management -----------------------------*/ 709 static int 710 xbd_alloc_ring(struct xbd_softc *sc) 711 { 712 blkif_sring_t *sring; 713 uintptr_t sring_page_addr; 714 int error; 715 int i; 716 717 sring = malloc(sc->xbd_ring_pages * PAGE_SIZE, M_XENBLOCKFRONT, 718 M_NOWAIT|M_ZERO); 719 if (sring == NULL) { 720 xenbus_dev_fatal(sc->xbd_dev, ENOMEM, "allocating shared ring"); 721 return (ENOMEM); 722 } 723 SHARED_RING_INIT(sring); 724 FRONT_RING_INIT(&sc->xbd_ring, sring, sc->xbd_ring_pages * PAGE_SIZE); 725 726 for (i = 0, sring_page_addr = (uintptr_t)sring; 727 i < sc->xbd_ring_pages; 728 i++, sring_page_addr += PAGE_SIZE) { 729 730 error = xenbus_grant_ring(sc->xbd_dev, 731 (vtomach(sring_page_addr) >> PAGE_SHIFT), 732 &sc->xbd_ring_ref[i]); 733 if (error) { 734 xenbus_dev_fatal(sc->xbd_dev, error, 735 "granting ring_ref(%d)", i); 736 return (error); 737 } 738 } 739 if (sc->xbd_ring_pages == 1) { 740 error = xs_printf(XST_NIL, xenbus_get_node(sc->xbd_dev), 741 "ring-ref", "%u", sc->xbd_ring_ref[0]); 742 if (error) { 743 xenbus_dev_fatal(sc->xbd_dev, error, 744 "writing %s/ring-ref", 745 xenbus_get_node(sc->xbd_dev)); 746 return (error); 747 } 748 } else { 749 for (i = 0; i < sc->xbd_ring_pages; i++) { 750 char ring_ref_name[]= "ring_refXX"; 751 752 snprintf(ring_ref_name, sizeof(ring_ref_name), 753 "ring-ref%u", i); 754 error = xs_printf(XST_NIL, xenbus_get_node(sc->xbd_dev), 755 ring_ref_name, "%u", sc->xbd_ring_ref[i]); 756 if (error) { 757 xenbus_dev_fatal(sc->xbd_dev, error, 758 "writing %s/%s", 759 xenbus_get_node(sc->xbd_dev), 760 ring_ref_name); 761 return (error); 762 } 763 } 764 } 765 766 error = xen_intr_alloc_and_bind_local_port(sc->xbd_dev, 767 xenbus_get_otherend_id(sc->xbd_dev), NULL, xbd_int, sc, 768 INTR_TYPE_BIO | INTR_MPSAFE, &sc->xen_intr_handle); 769 if (error) { 770 xenbus_dev_fatal(sc->xbd_dev, error, 771 "xen_intr_alloc_and_bind_local_port failed"); 772 return (error); 773 } 774 775 return (0); 776 } 777 778 static void 779 xbd_free_ring(struct xbd_softc *sc) 780 { 781 int i; 782 783 if (sc->xbd_ring.sring == NULL) 784 return; 785 786 for (i = 0; i < sc->xbd_ring_pages; i++) { 787 if (sc->xbd_ring_ref[i] != GRANT_REF_INVALID) { 788 gnttab_end_foreign_access_ref(sc->xbd_ring_ref[i]); 789 sc->xbd_ring_ref[i] = GRANT_REF_INVALID; 790 } 791 } 792 free(sc->xbd_ring.sring, M_XENBLOCKFRONT); 793 sc->xbd_ring.sring = NULL; 794 } 795 796 /*-------------------------- Initialization/Teardown -------------------------*/ 797 static int 798 xbd_feature_string(struct xbd_softc *sc, char *features, size_t len) 799 { 800 struct sbuf sb; 801 int feature_cnt; 802 803 sbuf_new(&sb, features, len, SBUF_FIXEDLEN); 804 805 feature_cnt = 0; 806 if ((sc->xbd_flags & XBDF_FLUSH) != 0) { 807 sbuf_printf(&sb, "flush"); 808 feature_cnt++; 809 } 810 811 if ((sc->xbd_flags & XBDF_BARRIER) != 0) { 812 if (feature_cnt != 0) 813 sbuf_printf(&sb, ", "); 814 sbuf_printf(&sb, "write_barrier"); 815 feature_cnt++; 816 } 817 818 (void) sbuf_finish(&sb); 819 return (sbuf_len(&sb)); 820 } 821 822 static int 823 xbd_sysctl_features(SYSCTL_HANDLER_ARGS) 824 { 825 char features[80]; 826 struct xbd_softc *sc = arg1; 827 int error; 828 int len; 829 830 error = sysctl_wire_old_buffer(req, 0); 831 if (error != 0) 832 return (error); 833 834 len = xbd_feature_string(sc, features, sizeof(features)); 835 836 /* len is -1 on error, which will make the SYSCTL_OUT a no-op. */ 837 return (SYSCTL_OUT(req, features, len + 1/*NUL*/)); 838 } 839 840 static void 841 xbd_setup_sysctl(struct xbd_softc *xbd) 842 { 843 struct sysctl_ctx_list *sysctl_ctx = NULL; 844 struct sysctl_oid *sysctl_tree = NULL; 845 struct sysctl_oid_list *children; 846 847 sysctl_ctx = device_get_sysctl_ctx(xbd->xbd_dev); 848 if (sysctl_ctx == NULL) 849 return; 850 851 sysctl_tree = device_get_sysctl_tree(xbd->xbd_dev); 852 if (sysctl_tree == NULL) 853 return; 854 855 children = SYSCTL_CHILDREN(sysctl_tree); 856 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 857 "max_requests", CTLFLAG_RD, &xbd->xbd_max_requests, -1, 858 "maximum outstanding requests (negotiated)"); 859 860 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 861 "max_request_segments", CTLFLAG_RD, 862 &xbd->xbd_max_request_segments, 0, 863 "maximum number of pages per requests (negotiated)"); 864 865 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 866 "max_request_size", CTLFLAG_RD, &xbd->xbd_max_request_size, 0, 867 "maximum size in bytes of a request (negotiated)"); 868 869 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 870 "ring_pages", CTLFLAG_RD, &xbd->xbd_ring_pages, 0, 871 "communication channel pages (negotiated)"); 872 873 SYSCTL_ADD_PROC(sysctl_ctx, children, OID_AUTO, 874 "features", CTLTYPE_STRING|CTLFLAG_RD, xbd, 0, 875 xbd_sysctl_features, "A", "protocol features (negotiated)"); 876 } 877 878 /* 879 * Translate Linux major/minor to an appropriate name and unit 880 * number. For HVM guests, this allows us to use the same drive names 881 * with blkfront as the emulated drives, easing transition slightly. 882 */ 883 static void 884 xbd_vdevice_to_unit(uint32_t vdevice, int *unit, const char **name) 885 { 886 static struct vdev_info { 887 int major; 888 int shift; 889 int base; 890 const char *name; 891 } info[] = { 892 {3, 6, 0, "ada"}, /* ide0 */ 893 {22, 6, 2, "ada"}, /* ide1 */ 894 {33, 6, 4, "ada"}, /* ide2 */ 895 {34, 6, 6, "ada"}, /* ide3 */ 896 {56, 6, 8, "ada"}, /* ide4 */ 897 {57, 6, 10, "ada"}, /* ide5 */ 898 {88, 6, 12, "ada"}, /* ide6 */ 899 {89, 6, 14, "ada"}, /* ide7 */ 900 {90, 6, 16, "ada"}, /* ide8 */ 901 {91, 6, 18, "ada"}, /* ide9 */ 902 903 {8, 4, 0, "da"}, /* scsi disk0 */ 904 {65, 4, 16, "da"}, /* scsi disk1 */ 905 {66, 4, 32, "da"}, /* scsi disk2 */ 906 {67, 4, 48, "da"}, /* scsi disk3 */ 907 {68, 4, 64, "da"}, /* scsi disk4 */ 908 {69, 4, 80, "da"}, /* scsi disk5 */ 909 {70, 4, 96, "da"}, /* scsi disk6 */ 910 {71, 4, 112, "da"}, /* scsi disk7 */ 911 {128, 4, 128, "da"}, /* scsi disk8 */ 912 {129, 4, 144, "da"}, /* scsi disk9 */ 913 {130, 4, 160, "da"}, /* scsi disk10 */ 914 {131, 4, 176, "da"}, /* scsi disk11 */ 915 {132, 4, 192, "da"}, /* scsi disk12 */ 916 {133, 4, 208, "da"}, /* scsi disk13 */ 917 {134, 4, 224, "da"}, /* scsi disk14 */ 918 {135, 4, 240, "da"}, /* scsi disk15 */ 919 920 {202, 4, 0, "xbd"}, /* xbd */ 921 922 {0, 0, 0, NULL}, 923 }; 924 int major = vdevice >> 8; 925 int minor = vdevice & 0xff; 926 int i; 927 928 if (vdevice & (1 << 28)) { 929 *unit = (vdevice & ((1 << 28) - 1)) >> 8; 930 *name = "xbd"; 931 return; 932 } 933 934 for (i = 0; info[i].major; i++) { 935 if (info[i].major == major) { 936 *unit = info[i].base + (minor >> info[i].shift); 937 *name = info[i].name; 938 return; 939 } 940 } 941 942 *unit = minor >> 4; 943 *name = "xbd"; 944 } 945 946 int 947 xbd_instance_create(struct xbd_softc *sc, blkif_sector_t sectors, 948 int vdevice, uint16_t vdisk_info, unsigned long sector_size) 949 { 950 char features[80]; 951 int unit, error = 0; 952 const char *name; 953 954 xbd_vdevice_to_unit(vdevice, &unit, &name); 955 956 sc->xbd_unit = unit; 957 958 if (strcmp(name, "xbd") != 0) 959 device_printf(sc->xbd_dev, "attaching as %s%d\n", name, unit); 960 961 if (xbd_feature_string(sc, features, sizeof(features)) > 0) { 962 device_printf(sc->xbd_dev, "features: %s\n", 963 features); 964 } 965 966 sc->xbd_disk = disk_alloc(); 967 sc->xbd_disk->d_unit = sc->xbd_unit; 968 sc->xbd_disk->d_open = xbd_open; 969 sc->xbd_disk->d_close = xbd_close; 970 sc->xbd_disk->d_ioctl = xbd_ioctl; 971 sc->xbd_disk->d_strategy = xbd_strategy; 972 sc->xbd_disk->d_dump = xbd_dump; 973 sc->xbd_disk->d_name = name; 974 sc->xbd_disk->d_drv1 = sc; 975 sc->xbd_disk->d_sectorsize = sector_size; 976 977 sc->xbd_disk->d_mediasize = sectors * sector_size; 978 sc->xbd_disk->d_maxsize = sc->xbd_max_request_size; 979 sc->xbd_disk->d_flags = 0; 980 if ((sc->xbd_flags & (XBDF_FLUSH|XBDF_BARRIER)) != 0) { 981 sc->xbd_disk->d_flags |= DISKFLAG_CANFLUSHCACHE; 982 device_printf(sc->xbd_dev, 983 "synchronize cache commands enabled.\n"); 984 } 985 disk_create(sc->xbd_disk, DISK_VERSION); 986 987 return error; 988 } 989 990 static void 991 xbd_free(struct xbd_softc *sc) 992 { 993 int i; 994 995 /* Prevent new requests being issued until we fix things up. */ 996 mtx_lock(&sc->xbd_io_lock); 997 sc->xbd_state = XBD_STATE_DISCONNECTED; 998 mtx_unlock(&sc->xbd_io_lock); 999 1000 /* Free resources associated with old device channel. */ 1001 xbd_free_ring(sc); 1002 if (sc->xbd_shadow) { 1003 1004 for (i = 0; i < sc->xbd_max_requests; i++) { 1005 struct xbd_command *cm; 1006 1007 cm = &sc->xbd_shadow[i]; 1008 if (cm->cm_sg_refs != NULL) { 1009 free(cm->cm_sg_refs, M_XENBLOCKFRONT); 1010 cm->cm_sg_refs = NULL; 1011 } 1012 1013 bus_dmamap_destroy(sc->xbd_io_dmat, cm->cm_map); 1014 } 1015 free(sc->xbd_shadow, M_XENBLOCKFRONT); 1016 sc->xbd_shadow = NULL; 1017 1018 bus_dma_tag_destroy(sc->xbd_io_dmat); 1019 1020 xbd_initq_cm(sc, XBD_Q_FREE); 1021 xbd_initq_cm(sc, XBD_Q_READY); 1022 xbd_initq_cm(sc, XBD_Q_COMPLETE); 1023 } 1024 1025 xen_intr_unbind(&sc->xen_intr_handle); 1026 1027 } 1028 1029 /*--------------------------- State Change Handlers --------------------------*/ 1030 static void 1031 xbd_initialize(struct xbd_softc *sc) 1032 { 1033 const char *otherend_path; 1034 const char *node_path; 1035 uint32_t max_ring_page_order; 1036 int error; 1037 int i; 1038 1039 if (xenbus_get_state(sc->xbd_dev) != XenbusStateInitialising) { 1040 /* Initialization has already been performed. */ 1041 return; 1042 } 1043 1044 /* 1045 * Protocol defaults valid even if negotiation for a 1046 * setting fails. 1047 */ 1048 max_ring_page_order = 0; 1049 sc->xbd_ring_pages = 1; 1050 sc->xbd_max_request_segments = BLKIF_MAX_SEGMENTS_PER_REQUEST; 1051 sc->xbd_max_request_size = 1052 XBD_SEGS_TO_SIZE(sc->xbd_max_request_segments); 1053 1054 /* 1055 * Protocol negotiation. 1056 * 1057 * \note xs_gather() returns on the first encountered error, so 1058 * we must use independant calls in order to guarantee 1059 * we don't miss information in a sparsly populated back-end 1060 * tree. 1061 * 1062 * \note xs_scanf() does not update variables for unmatched 1063 * fields. 1064 */ 1065 otherend_path = xenbus_get_otherend_path(sc->xbd_dev); 1066 node_path = xenbus_get_node(sc->xbd_dev); 1067 1068 /* Support both backend schemes for relaying ring page limits. */ 1069 (void)xs_scanf(XST_NIL, otherend_path, 1070 "max-ring-page-order", NULL, "%" PRIu32, 1071 &max_ring_page_order); 1072 sc->xbd_ring_pages = 1 << max_ring_page_order; 1073 (void)xs_scanf(XST_NIL, otherend_path, 1074 "max-ring-pages", NULL, "%" PRIu32, 1075 &sc->xbd_ring_pages); 1076 if (sc->xbd_ring_pages < 1) 1077 sc->xbd_ring_pages = 1; 1078 1079 if (sc->xbd_ring_pages > XBD_MAX_RING_PAGES) { 1080 device_printf(sc->xbd_dev, 1081 "Back-end specified ring-pages of %u " 1082 "limited to front-end limit of %u.\n", 1083 sc->xbd_ring_pages, XBD_MAX_RING_PAGES); 1084 sc->xbd_ring_pages = XBD_MAX_RING_PAGES; 1085 } 1086 1087 if (powerof2(sc->xbd_ring_pages) == 0) { 1088 uint32_t new_page_limit; 1089 1090 new_page_limit = 0x01 << (fls(sc->xbd_ring_pages) - 1); 1091 device_printf(sc->xbd_dev, 1092 "Back-end specified ring-pages of %u " 1093 "is not a power of 2. Limited to %u.\n", 1094 sc->xbd_ring_pages, new_page_limit); 1095 sc->xbd_ring_pages = new_page_limit; 1096 } 1097 1098 sc->xbd_max_requests = 1099 BLKIF_MAX_RING_REQUESTS(sc->xbd_ring_pages * PAGE_SIZE); 1100 if (sc->xbd_max_requests > XBD_MAX_REQUESTS) { 1101 device_printf(sc->xbd_dev, 1102 "Back-end specified max_requests of %u " 1103 "limited to front-end limit of %zu.\n", 1104 sc->xbd_max_requests, XBD_MAX_REQUESTS); 1105 sc->xbd_max_requests = XBD_MAX_REQUESTS; 1106 } 1107 1108 /* Allocate datastructures based on negotiated values. */ 1109 error = bus_dma_tag_create( 1110 bus_get_dma_tag(sc->xbd_dev), /* parent */ 1111 512, PAGE_SIZE, /* algnmnt, boundary */ 1112 BUS_SPACE_MAXADDR, /* lowaddr */ 1113 BUS_SPACE_MAXADDR, /* highaddr */ 1114 NULL, NULL, /* filter, filterarg */ 1115 sc->xbd_max_request_size, 1116 sc->xbd_max_request_segments, 1117 PAGE_SIZE, /* maxsegsize */ 1118 BUS_DMA_ALLOCNOW, /* flags */ 1119 busdma_lock_mutex, /* lockfunc */ 1120 &sc->xbd_io_lock, /* lockarg */ 1121 &sc->xbd_io_dmat); 1122 if (error != 0) { 1123 xenbus_dev_fatal(sc->xbd_dev, error, 1124 "Cannot allocate parent DMA tag\n"); 1125 return; 1126 } 1127 1128 /* Per-transaction data allocation. */ 1129 sc->xbd_shadow = malloc(sizeof(*sc->xbd_shadow) * sc->xbd_max_requests, 1130 M_XENBLOCKFRONT, M_NOWAIT|M_ZERO); 1131 if (sc->xbd_shadow == NULL) { 1132 bus_dma_tag_destroy(sc->xbd_io_dmat); 1133 xenbus_dev_fatal(sc->xbd_dev, error, 1134 "Cannot allocate request structures\n"); 1135 return; 1136 } 1137 1138 for (i = 0; i < sc->xbd_max_requests; i++) { 1139 struct xbd_command *cm; 1140 1141 cm = &sc->xbd_shadow[i]; 1142 cm->cm_sg_refs = malloc( 1143 sizeof(grant_ref_t) * sc->xbd_max_request_segments, 1144 M_XENBLOCKFRONT, M_NOWAIT); 1145 if (cm->cm_sg_refs == NULL) 1146 break; 1147 cm->cm_id = i; 1148 cm->cm_flags = XBDCF_INITIALIZER; 1149 cm->cm_sc = sc; 1150 if (bus_dmamap_create(sc->xbd_io_dmat, 0, &cm->cm_map) != 0) 1151 break; 1152 xbd_free_command(cm); 1153 } 1154 1155 if (xbd_alloc_ring(sc) != 0) 1156 return; 1157 1158 /* Support both backend schemes for relaying ring page limits. */ 1159 if (sc->xbd_ring_pages > 1) { 1160 error = xs_printf(XST_NIL, node_path, 1161 "num-ring-pages","%u", 1162 sc->xbd_ring_pages); 1163 if (error) { 1164 xenbus_dev_fatal(sc->xbd_dev, error, 1165 "writing %s/num-ring-pages", 1166 node_path); 1167 return; 1168 } 1169 1170 error = xs_printf(XST_NIL, node_path, 1171 "ring-page-order", "%u", 1172 fls(sc->xbd_ring_pages) - 1); 1173 if (error) { 1174 xenbus_dev_fatal(sc->xbd_dev, error, 1175 "writing %s/ring-page-order", 1176 node_path); 1177 return; 1178 } 1179 } 1180 1181 error = xs_printf(XST_NIL, node_path, "event-channel", 1182 "%u", xen_intr_port(sc->xen_intr_handle)); 1183 if (error) { 1184 xenbus_dev_fatal(sc->xbd_dev, error, 1185 "writing %s/event-channel", 1186 node_path); 1187 return; 1188 } 1189 1190 error = xs_printf(XST_NIL, node_path, "protocol", 1191 "%s", XEN_IO_PROTO_ABI_NATIVE); 1192 if (error) { 1193 xenbus_dev_fatal(sc->xbd_dev, error, 1194 "writing %s/protocol", 1195 node_path); 1196 return; 1197 } 1198 1199 xenbus_set_state(sc->xbd_dev, XenbusStateInitialised); 1200 } 1201 1202 /* 1203 * Invoked when the backend is finally 'ready' (and has published 1204 * the details about the physical device - #sectors, size, etc). 1205 */ 1206 static void 1207 xbd_connect(struct xbd_softc *sc) 1208 { 1209 device_t dev = sc->xbd_dev; 1210 unsigned long sectors, sector_size; 1211 unsigned int binfo; 1212 int err, feature_barrier, feature_flush; 1213 1214 if (sc->xbd_state == XBD_STATE_CONNECTED || 1215 sc->xbd_state == XBD_STATE_SUSPENDED) 1216 return; 1217 1218 DPRINTK("blkfront.c:connect:%s.\n", xenbus_get_otherend_path(dev)); 1219 1220 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev), 1221 "sectors", "%lu", §ors, 1222 "info", "%u", &binfo, 1223 "sector-size", "%lu", §or_size, 1224 NULL); 1225 if (err) { 1226 xenbus_dev_fatal(dev, err, 1227 "reading backend fields at %s", 1228 xenbus_get_otherend_path(dev)); 1229 return; 1230 } 1231 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev), 1232 "feature-barrier", "%lu", &feature_barrier, 1233 NULL); 1234 if (err == 0 && feature_barrier != 0) 1235 sc->xbd_flags |= XBDF_BARRIER; 1236 1237 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev), 1238 "feature-flush-cache", "%lu", &feature_flush, 1239 NULL); 1240 if (err == 0 && feature_flush != 0) 1241 sc->xbd_flags |= XBDF_FLUSH; 1242 1243 if (sc->xbd_disk == NULL) { 1244 device_printf(dev, "%juMB <%s> at %s", 1245 (uintmax_t) sectors / (1048576 / sector_size), 1246 device_get_desc(dev), 1247 xenbus_get_node(dev)); 1248 bus_print_child_footer(device_get_parent(dev), dev); 1249 1250 xbd_instance_create(sc, sectors, sc->xbd_vdevice, binfo, 1251 sector_size); 1252 } 1253 1254 (void)xenbus_set_state(dev, XenbusStateConnected); 1255 1256 /* Kick pending requests. */ 1257 mtx_lock(&sc->xbd_io_lock); 1258 sc->xbd_state = XBD_STATE_CONNECTED; 1259 xbd_startio(sc); 1260 sc->xbd_flags |= XBDF_READY; 1261 mtx_unlock(&sc->xbd_io_lock); 1262 } 1263 1264 /** 1265 * Handle the change of state of the backend to Closing. We must delete our 1266 * device-layer structures now, to ensure that writes are flushed through to 1267 * the backend. Once this is done, we can switch to Closed in 1268 * acknowledgement. 1269 */ 1270 static void 1271 xbd_closing(device_t dev) 1272 { 1273 struct xbd_softc *sc = device_get_softc(dev); 1274 1275 xenbus_set_state(dev, XenbusStateClosing); 1276 1277 DPRINTK("xbd_closing: %s removed\n", xenbus_get_node(dev)); 1278 1279 if (sc->xbd_disk != NULL) { 1280 disk_destroy(sc->xbd_disk); 1281 sc->xbd_disk = NULL; 1282 } 1283 1284 xenbus_set_state(dev, XenbusStateClosed); 1285 } 1286 1287 /*---------------------------- NewBus Entrypoints ----------------------------*/ 1288 static int 1289 xbd_probe(device_t dev) 1290 { 1291 if (strcmp(xenbus_get_type(dev), "vbd") != 0) 1292 return (ENXIO); 1293 1294 if (xen_hvm_domain()) { 1295 int error; 1296 char *type; 1297 1298 /* 1299 * When running in an HVM domain, IDE disk emulation is 1300 * disabled early in boot so that native drivers will 1301 * not see emulated hardware. However, CDROM device 1302 * emulation cannot be disabled. 1303 * 1304 * Through use of FreeBSD's vm_guest and xen_hvm_domain() 1305 * APIs, we could modify the native CDROM driver to fail its 1306 * probe when running under Xen. Unfortunatlely, the PV 1307 * CDROM support in XenServer (up through at least version 1308 * 6.2) isn't functional, so we instead rely on the emulated 1309 * CDROM instance, and fail to attach the PV one here in 1310 * the blkfront driver. 1311 */ 1312 error = xs_read(XST_NIL, xenbus_get_node(dev), 1313 "device-type", NULL, (void **) &type); 1314 if (error) 1315 return (ENXIO); 1316 1317 if (strncmp(type, "cdrom", 5) == 0) { 1318 free(type, M_XENSTORE); 1319 return (ENXIO); 1320 } 1321 free(type, M_XENSTORE); 1322 } 1323 1324 device_set_desc(dev, "Virtual Block Device"); 1325 device_quiet(dev); 1326 return (0); 1327 } 1328 1329 /* 1330 * Setup supplies the backend dir, virtual device. We place an event 1331 * channel and shared frame entries. We watch backend to wait if it's 1332 * ok. 1333 */ 1334 static int 1335 xbd_attach(device_t dev) 1336 { 1337 struct xbd_softc *sc; 1338 const char *name; 1339 uint32_t vdevice; 1340 int error; 1341 int i; 1342 int unit; 1343 1344 /* FIXME: Use dynamic device id if this is not set. */ 1345 error = xs_scanf(XST_NIL, xenbus_get_node(dev), 1346 "virtual-device", NULL, "%" PRIu32, &vdevice); 1347 if (error) 1348 error = xs_scanf(XST_NIL, xenbus_get_node(dev), 1349 "virtual-device-ext", NULL, "%" PRIu32, &vdevice); 1350 if (error) { 1351 xenbus_dev_fatal(dev, error, "reading virtual-device"); 1352 device_printf(dev, "Couldn't determine virtual device.\n"); 1353 return (error); 1354 } 1355 1356 xbd_vdevice_to_unit(vdevice, &unit, &name); 1357 if (!strcmp(name, "xbd")) 1358 device_set_unit(dev, unit); 1359 1360 sc = device_get_softc(dev); 1361 mtx_init(&sc->xbd_io_lock, "blkfront i/o lock", NULL, MTX_DEF); 1362 xbd_initqs(sc); 1363 for (i = 0; i < XBD_MAX_RING_PAGES; i++) 1364 sc->xbd_ring_ref[i] = GRANT_REF_INVALID; 1365 1366 sc->xbd_dev = dev; 1367 sc->xbd_vdevice = vdevice; 1368 sc->xbd_state = XBD_STATE_DISCONNECTED; 1369 1370 xbd_setup_sysctl(sc); 1371 1372 /* Wait for backend device to publish its protocol capabilities. */ 1373 xenbus_set_state(dev, XenbusStateInitialising); 1374 1375 return (0); 1376 } 1377 1378 static int 1379 xbd_detach(device_t dev) 1380 { 1381 struct xbd_softc *sc = device_get_softc(dev); 1382 1383 DPRINTK("%s: %s removed\n", __func__, xenbus_get_node(dev)); 1384 1385 xbd_free(sc); 1386 mtx_destroy(&sc->xbd_io_lock); 1387 1388 return 0; 1389 } 1390 1391 static int 1392 xbd_suspend(device_t dev) 1393 { 1394 struct xbd_softc *sc = device_get_softc(dev); 1395 int retval; 1396 int saved_state; 1397 1398 /* Prevent new requests being issued until we fix things up. */ 1399 mtx_lock(&sc->xbd_io_lock); 1400 saved_state = sc->xbd_state; 1401 sc->xbd_state = XBD_STATE_SUSPENDED; 1402 1403 /* Wait for outstanding I/O to drain. */ 1404 retval = 0; 1405 while (xbd_queue_length(sc, XBD_Q_BUSY) != 0) { 1406 if (msleep(&sc->xbd_cm_q[XBD_Q_BUSY], &sc->xbd_io_lock, 1407 PRIBIO, "blkf_susp", 30 * hz) == EWOULDBLOCK) { 1408 retval = EBUSY; 1409 break; 1410 } 1411 } 1412 mtx_unlock(&sc->xbd_io_lock); 1413 1414 if (retval != 0) 1415 sc->xbd_state = saved_state; 1416 1417 return (retval); 1418 } 1419 1420 static int 1421 xbd_resume(device_t dev) 1422 { 1423 struct xbd_softc *sc = device_get_softc(dev); 1424 1425 DPRINTK("xbd_resume: %s\n", xenbus_get_node(dev)); 1426 1427 xbd_free(sc); 1428 xbd_initialize(sc); 1429 return (0); 1430 } 1431 1432 /** 1433 * Callback received when the backend's state changes. 1434 */ 1435 static void 1436 xbd_backend_changed(device_t dev, XenbusState backend_state) 1437 { 1438 struct xbd_softc *sc = device_get_softc(dev); 1439 1440 DPRINTK("backend_state=%d\n", backend_state); 1441 1442 switch (backend_state) { 1443 case XenbusStateUnknown: 1444 case XenbusStateInitialising: 1445 case XenbusStateReconfigured: 1446 case XenbusStateReconfiguring: 1447 case XenbusStateClosed: 1448 break; 1449 1450 case XenbusStateInitWait: 1451 case XenbusStateInitialised: 1452 xbd_initialize(sc); 1453 break; 1454 1455 case XenbusStateConnected: 1456 xbd_initialize(sc); 1457 xbd_connect(sc); 1458 break; 1459 1460 case XenbusStateClosing: 1461 if (sc->xbd_users > 0) 1462 xenbus_dev_error(dev, -EBUSY, 1463 "Device in use; refusing to close"); 1464 else 1465 xbd_closing(dev); 1466 break; 1467 } 1468 } 1469 1470 /*---------------------------- NewBus Registration ---------------------------*/ 1471 static device_method_t xbd_methods[] = { 1472 /* Device interface */ 1473 DEVMETHOD(device_probe, xbd_probe), 1474 DEVMETHOD(device_attach, xbd_attach), 1475 DEVMETHOD(device_detach, xbd_detach), 1476 DEVMETHOD(device_shutdown, bus_generic_shutdown), 1477 DEVMETHOD(device_suspend, xbd_suspend), 1478 DEVMETHOD(device_resume, xbd_resume), 1479 1480 /* Xenbus interface */ 1481 DEVMETHOD(xenbus_otherend_changed, xbd_backend_changed), 1482 1483 { 0, 0 } 1484 }; 1485 1486 static driver_t xbd_driver = { 1487 "xbd", 1488 xbd_methods, 1489 sizeof(struct xbd_softc), 1490 }; 1491 devclass_t xbd_devclass; 1492 1493 DRIVER_MODULE(xbd, xenbusb_front, xbd_driver, xbd_devclass, 0, 0); 1494