blkfront.c revision 287801
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: stable/10/sys/dev/xen/blkfront/blkfront.c 287801 2015-09-14 19:35:33Z cperciva $"); 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 ---------------------------*/ 72static void xbd_closing(device_t); 73static 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 ----------------------------*/ 85static MALLOC_DEFINE(M_XENBLOCKFRONT, "xbd", "Xen Block Front driver data"); 86 87/*---------------------------- Command Processing ----------------------------*/ 88static void 89xbd_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 98static void 99xbd_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 112static void 113xbd_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 122static void 123xbd_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 132static inline void 133xbd_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 143static void 144xbd_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 158static void 159xbd_mksegarray(bus_dma_segment_t *segs, int nsegs, 160 grant_ref_t * gref_head, int otherend_id, int readonly, 161 grant_ref_t * sg_ref, blkif_request_segment_t * sg) 162{ 163 struct blkif_request_segment *last_block_sg = sg + nsegs; 164 vm_paddr_t buffer_ma; 165 uint64_t fsect, lsect; 166 int ref; 167 168 while (sg < last_block_sg) { 169 buffer_ma = segs->ds_addr; 170 fsect = (buffer_ma & PAGE_MASK) >> XBD_SECTOR_SHFT; 171 lsect = fsect + (segs->ds_len >> XBD_SECTOR_SHFT) - 1; 172 173 KASSERT(lsect <= 7, ("XEN disk driver data cannot " 174 "cross a page boundary")); 175 176 /* install a grant reference. */ 177 ref = gnttab_claim_grant_reference(gref_head); 178 179 /* 180 * GNTTAB_LIST_END == 0xffffffff, but it is private 181 * to gnttab.c. 182 */ 183 KASSERT(ref != ~0, ("grant_reference failed")); 184 185 gnttab_grant_foreign_access_ref( 186 ref, 187 otherend_id, 188 buffer_ma >> PAGE_SHIFT, 189 readonly); 190 191 *sg_ref = ref; 192 *sg = (struct blkif_request_segment) { 193 .gref = ref, 194 .first_sect = fsect, 195 .last_sect = lsect 196 }; 197 sg++; 198 sg_ref++; 199 segs++; 200 } 201} 202 203static void 204xbd_queue_cb(void *arg, bus_dma_segment_t *segs, int nsegs, int error) 205{ 206 struct xbd_softc *sc; 207 struct xbd_command *cm; 208 blkif_request_t *ring_req; 209 int op; 210 211 cm = arg; 212 sc = cm->cm_sc; 213 214 if (error) { 215 cm->cm_bp->bio_error = EIO; 216 biodone(cm->cm_bp); 217 xbd_free_command(cm); 218 return; 219 } 220 221 KASSERT(nsegs <= BLKIF_MAX_SEGMENTS_PER_REQUEST, 222 ("Too many segments in a blkfront I/O")); 223 224 /* Fill out a communications ring structure. */ 225 ring_req = RING_GET_REQUEST(&sc->xbd_ring, sc->xbd_ring.req_prod_pvt); 226 sc->xbd_ring.req_prod_pvt++; 227 ring_req->id = cm->cm_id; 228 ring_req->operation = cm->cm_operation; 229 ring_req->sector_number = cm->cm_sector_number; 230 ring_req->handle = (blkif_vdev_t)(uintptr_t)sc->xbd_disk; 231 ring_req->nr_segments = nsegs; 232 cm->cm_nseg = nsegs; 233 xbd_mksegarray(segs, nsegs, &cm->cm_gref_head, 234 xenbus_get_otherend_id(sc->xbd_dev), 235 cm->cm_operation == BLKIF_OP_WRITE, 236 cm->cm_sg_refs, ring_req->seg); 237 238 if (cm->cm_operation == BLKIF_OP_READ) 239 op = BUS_DMASYNC_PREREAD; 240 else if (cm->cm_operation == BLKIF_OP_WRITE) 241 op = BUS_DMASYNC_PREWRITE; 242 else 243 op = 0; 244 bus_dmamap_sync(sc->xbd_io_dmat, cm->cm_map, op); 245 246 gnttab_free_grant_references(cm->cm_gref_head); 247 248 xbd_enqueue_cm(cm, XBD_Q_BUSY); 249 250 /* 251 * If bus dma had to asynchronously call us back to dispatch 252 * this command, we are no longer executing in the context of 253 * xbd_startio(). Thus we cannot rely on xbd_startio()'s call to 254 * xbd_flush_requests() to publish this command to the backend 255 * along with any other commands that it could batch. 256 */ 257 if ((cm->cm_flags & XBDCF_ASYNC_MAPPING) != 0) 258 xbd_flush_requests(sc); 259 260 return; 261} 262 263static int 264xbd_queue_request(struct xbd_softc *sc, struct xbd_command *cm) 265{ 266 int error; 267 268 error = bus_dmamap_load(sc->xbd_io_dmat, cm->cm_map, cm->cm_data, 269 cm->cm_datalen, xbd_queue_cb, cm, 0); 270 if (error == EINPROGRESS) { 271 /* 272 * Maintain queuing order by freezing the queue. The next 273 * command may not require as many resources as the command 274 * we just attempted to map, so we can't rely on bus dma 275 * blocking for it too. 276 */ 277 xbd_cm_freeze(sc, cm, XBDCF_ASYNC_MAPPING); 278 return (0); 279 } 280 281 return (error); 282} 283 284static void 285xbd_restart_queue_callback(void *arg) 286{ 287 struct xbd_softc *sc = arg; 288 289 mtx_lock(&sc->xbd_io_lock); 290 291 xbd_thaw(sc, XBDF_GNT_SHORTAGE); 292 293 xbd_startio(sc); 294 295 mtx_unlock(&sc->xbd_io_lock); 296} 297 298static struct xbd_command * 299xbd_bio_command(struct xbd_softc *sc) 300{ 301 struct xbd_command *cm; 302 struct bio *bp; 303 304 if (__predict_false(sc->xbd_state != XBD_STATE_CONNECTED)) 305 return (NULL); 306 307 bp = xbd_dequeue_bio(sc); 308 if (bp == NULL) 309 return (NULL); 310 311 if ((cm = xbd_dequeue_cm(sc, XBD_Q_FREE)) == NULL) { 312 xbd_freeze(sc, XBDF_CM_SHORTAGE); 313 xbd_requeue_bio(sc, bp); 314 return (NULL); 315 } 316 317 if (gnttab_alloc_grant_references(sc->xbd_max_request_segments, 318 &cm->cm_gref_head) != 0) { 319 gnttab_request_free_callback(&sc->xbd_callback, 320 xbd_restart_queue_callback, sc, 321 sc->xbd_max_request_segments); 322 xbd_freeze(sc, XBDF_GNT_SHORTAGE); 323 xbd_requeue_bio(sc, bp); 324 xbd_enqueue_cm(cm, XBD_Q_FREE); 325 return (NULL); 326 } 327 328 cm->cm_bp = bp; 329 cm->cm_data = bp->bio_data; 330 cm->cm_datalen = bp->bio_bcount; 331 cm->cm_sector_number = (blkif_sector_t)bp->bio_pblkno; 332 333 switch (bp->bio_cmd) { 334 case BIO_READ: 335 cm->cm_operation = BLKIF_OP_READ; 336 break; 337 case BIO_WRITE: 338 cm->cm_operation = BLKIF_OP_WRITE; 339 if ((bp->bio_flags & BIO_ORDERED) != 0) { 340 if ((sc->xbd_flags & XBDF_BARRIER) != 0) { 341 cm->cm_operation = BLKIF_OP_WRITE_BARRIER; 342 } else { 343 /* 344 * Single step this command. 345 */ 346 cm->cm_flags |= XBDCF_Q_FREEZE; 347 if (xbd_queue_length(sc, XBD_Q_BUSY) != 0) { 348 /* 349 * Wait for in-flight requests to 350 * finish. 351 */ 352 xbd_freeze(sc, XBDF_WAIT_IDLE); 353 xbd_requeue_cm(cm, XBD_Q_READY); 354 return (NULL); 355 } 356 } 357 } 358 break; 359 case BIO_FLUSH: 360 if ((sc->xbd_flags & XBDF_FLUSH) != 0) 361 cm->cm_operation = BLKIF_OP_FLUSH_DISKCACHE; 362 else if ((sc->xbd_flags & XBDF_BARRIER) != 0) 363 cm->cm_operation = BLKIF_OP_WRITE_BARRIER; 364 else 365 panic("flush request, but no flush support available"); 366 break; 367 default: 368 panic("unknown bio command %d", bp->bio_cmd); 369 } 370 371 return (cm); 372} 373 374/* 375 * Dequeue buffers and place them in the shared communication ring. 376 * Return when no more requests can be accepted or all buffers have 377 * been queued. 378 * 379 * Signal XEN once the ring has been filled out. 380 */ 381static void 382xbd_startio(struct xbd_softc *sc) 383{ 384 struct xbd_command *cm; 385 int error, queued = 0; 386 387 mtx_assert(&sc->xbd_io_lock, MA_OWNED); 388 389 if (sc->xbd_state != XBD_STATE_CONNECTED) 390 return; 391 392 while (!RING_FULL(&sc->xbd_ring)) { 393 394 if (sc->xbd_qfrozen_cnt != 0) 395 break; 396 397 cm = xbd_dequeue_cm(sc, XBD_Q_READY); 398 399 if (cm == NULL) 400 cm = xbd_bio_command(sc); 401 402 if (cm == NULL) 403 break; 404 405 if ((cm->cm_flags & XBDCF_Q_FREEZE) != 0) { 406 /* 407 * Single step command. Future work is 408 * held off until this command completes. 409 */ 410 xbd_cm_freeze(sc, cm, XBDCF_Q_FREEZE); 411 } 412 413 if ((error = xbd_queue_request(sc, cm)) != 0) { 414 printf("xbd_queue_request returned %d\n", error); 415 break; 416 } 417 queued++; 418 } 419 420 if (queued != 0) 421 xbd_flush_requests(sc); 422} 423 424static void 425xbd_bio_complete(struct xbd_softc *sc, struct xbd_command *cm) 426{ 427 struct bio *bp; 428 429 bp = cm->cm_bp; 430 431 if (__predict_false(cm->cm_status != BLKIF_RSP_OKAY)) { 432 disk_err(bp, "disk error" , -1, 0); 433 printf(" status: %x\n", cm->cm_status); 434 bp->bio_flags |= BIO_ERROR; 435 } 436 437 if (bp->bio_flags & BIO_ERROR) 438 bp->bio_error = EIO; 439 else 440 bp->bio_resid = 0; 441 442 xbd_free_command(cm); 443 biodone(bp); 444} 445 446static void 447xbd_int(void *xsc) 448{ 449 struct xbd_softc *sc = xsc; 450 struct xbd_command *cm; 451 blkif_response_t *bret; 452 RING_IDX i, rp; 453 int op; 454 455 mtx_lock(&sc->xbd_io_lock); 456 457 if (__predict_false(sc->xbd_state == XBD_STATE_DISCONNECTED)) { 458 mtx_unlock(&sc->xbd_io_lock); 459 return; 460 } 461 462 again: 463 rp = sc->xbd_ring.sring->rsp_prod; 464 rmb(); /* Ensure we see queued responses up to 'rp'. */ 465 466 for (i = sc->xbd_ring.rsp_cons; i != rp;) { 467 bret = RING_GET_RESPONSE(&sc->xbd_ring, i); 468 cm = &sc->xbd_shadow[bret->id]; 469 470 xbd_remove_cm(cm, XBD_Q_BUSY); 471 gnttab_end_foreign_access_references(cm->cm_nseg, 472 cm->cm_sg_refs); 473 i++; 474 475 if (cm->cm_operation == BLKIF_OP_READ) 476 op = BUS_DMASYNC_POSTREAD; 477 else if (cm->cm_operation == BLKIF_OP_WRITE || 478 cm->cm_operation == BLKIF_OP_WRITE_BARRIER) 479 op = BUS_DMASYNC_POSTWRITE; 480 else 481 op = 0; 482 bus_dmamap_sync(sc->xbd_io_dmat, cm->cm_map, op); 483 bus_dmamap_unload(sc->xbd_io_dmat, cm->cm_map); 484 485 /* 486 * Release any hold this command has on future command 487 * dispatch. 488 */ 489 xbd_cm_thaw(sc, cm); 490 491 /* 492 * Directly call the i/o complete routine to save an 493 * an indirection in the common case. 494 */ 495 cm->cm_status = bret->status; 496 if (cm->cm_bp) 497 xbd_bio_complete(sc, cm); 498 else if (cm->cm_complete != NULL) 499 cm->cm_complete(cm); 500 else 501 xbd_free_command(cm); 502 } 503 504 sc->xbd_ring.rsp_cons = i; 505 506 if (i != sc->xbd_ring.req_prod_pvt) { 507 int more_to_do; 508 RING_FINAL_CHECK_FOR_RESPONSES(&sc->xbd_ring, more_to_do); 509 if (more_to_do) 510 goto again; 511 } else { 512 sc->xbd_ring.sring->rsp_event = i + 1; 513 } 514 515 if (xbd_queue_length(sc, XBD_Q_BUSY) == 0) 516 xbd_thaw(sc, XBDF_WAIT_IDLE); 517 518 xbd_startio(sc); 519 520 if (__predict_false(sc->xbd_state == XBD_STATE_SUSPENDED)) 521 wakeup(&sc->xbd_cm_q[XBD_Q_BUSY]); 522 523 mtx_unlock(&sc->xbd_io_lock); 524} 525 526/*------------------------------- Dump Support -------------------------------*/ 527/** 528 * Quiesce the disk writes for a dump file before allowing the next buffer. 529 */ 530static void 531xbd_quiesce(struct xbd_softc *sc) 532{ 533 int mtd; 534 535 // While there are outstanding requests 536 while (xbd_queue_length(sc, XBD_Q_BUSY) != 0) { 537 RING_FINAL_CHECK_FOR_RESPONSES(&sc->xbd_ring, mtd); 538 if (mtd) { 539 /* Recieved request completions, update queue. */ 540 xbd_int(sc); 541 } 542 if (xbd_queue_length(sc, XBD_Q_BUSY) != 0) { 543 /* 544 * Still pending requests, wait for the disk i/o 545 * to complete. 546 */ 547 HYPERVISOR_yield(); 548 } 549 } 550} 551 552/* Kernel dump function for a paravirtualized disk device */ 553static void 554xbd_dump_complete(struct xbd_command *cm) 555{ 556 557 xbd_enqueue_cm(cm, XBD_Q_COMPLETE); 558} 559 560static int 561xbd_dump(void *arg, void *virtual, vm_offset_t physical, off_t offset, 562 size_t length) 563{ 564 struct disk *dp = arg; 565 struct xbd_softc *sc = dp->d_drv1; 566 struct xbd_command *cm; 567 size_t chunk; 568 int sbp; 569 int rc = 0; 570 571 if (length <= 0) 572 return (rc); 573 574 xbd_quiesce(sc); /* All quiet on the western front. */ 575 576 /* 577 * If this lock is held, then this module is failing, and a 578 * successful kernel dump is highly unlikely anyway. 579 */ 580 mtx_lock(&sc->xbd_io_lock); 581 582 /* Split the 64KB block as needed */ 583 for (sbp=0; length > 0; sbp++) { 584 cm = xbd_dequeue_cm(sc, XBD_Q_FREE); 585 if (cm == NULL) { 586 mtx_unlock(&sc->xbd_io_lock); 587 device_printf(sc->xbd_dev, "dump: no more commands?\n"); 588 return (EBUSY); 589 } 590 591 if (gnttab_alloc_grant_references(sc->xbd_max_request_segments, 592 &cm->cm_gref_head) != 0) { 593 xbd_free_command(cm); 594 mtx_unlock(&sc->xbd_io_lock); 595 device_printf(sc->xbd_dev, "no more grant allocs?\n"); 596 return (EBUSY); 597 } 598 599 chunk = length > sc->xbd_max_request_size ? 600 sc->xbd_max_request_size : length; 601 cm->cm_data = virtual; 602 cm->cm_datalen = chunk; 603 cm->cm_operation = BLKIF_OP_WRITE; 604 cm->cm_sector_number = offset / dp->d_sectorsize; 605 cm->cm_complete = xbd_dump_complete; 606 607 xbd_enqueue_cm(cm, XBD_Q_READY); 608 609 length -= chunk; 610 offset += chunk; 611 virtual = (char *) virtual + chunk; 612 } 613 614 /* Tell DOM0 to do the I/O */ 615 xbd_startio(sc); 616 mtx_unlock(&sc->xbd_io_lock); 617 618 /* Poll for the completion. */ 619 xbd_quiesce(sc); /* All quite on the eastern front */ 620 621 /* If there were any errors, bail out... */ 622 while ((cm = xbd_dequeue_cm(sc, XBD_Q_COMPLETE)) != NULL) { 623 if (cm->cm_status != BLKIF_RSP_OKAY) { 624 device_printf(sc->xbd_dev, 625 "Dump I/O failed at sector %jd\n", 626 cm->cm_sector_number); 627 rc = EIO; 628 } 629 xbd_free_command(cm); 630 } 631 632 return (rc); 633} 634 635/*----------------------------- Disk Entrypoints -----------------------------*/ 636static int 637xbd_open(struct disk *dp) 638{ 639 struct xbd_softc *sc = dp->d_drv1; 640 641 if (sc == NULL) { 642 printf("xb%d: not found", sc->xbd_unit); 643 return (ENXIO); 644 } 645 646 sc->xbd_flags |= XBDF_OPEN; 647 sc->xbd_users++; 648 return (0); 649} 650 651static int 652xbd_close(struct disk *dp) 653{ 654 struct xbd_softc *sc = dp->d_drv1; 655 656 if (sc == NULL) 657 return (ENXIO); 658 sc->xbd_flags &= ~XBDF_OPEN; 659 if (--(sc->xbd_users) == 0) { 660 /* 661 * Check whether we have been instructed to close. We will 662 * have ignored this request initially, as the device was 663 * still mounted. 664 */ 665 if (xenbus_get_otherend_state(sc->xbd_dev) == 666 XenbusStateClosing) 667 xbd_closing(sc->xbd_dev); 668 } 669 return (0); 670} 671 672static int 673xbd_ioctl(struct disk *dp, u_long cmd, void *addr, int flag, struct thread *td) 674{ 675 struct xbd_softc *sc = dp->d_drv1; 676 677 if (sc == NULL) 678 return (ENXIO); 679 680 return (ENOTTY); 681} 682 683/* 684 * Read/write routine for a buffer. Finds the proper unit, place it on 685 * the sortq and kick the controller. 686 */ 687static void 688xbd_strategy(struct bio *bp) 689{ 690 struct xbd_softc *sc = bp->bio_disk->d_drv1; 691 692 /* bogus disk? */ 693 if (sc == NULL) { 694 bp->bio_error = EINVAL; 695 bp->bio_flags |= BIO_ERROR; 696 bp->bio_resid = bp->bio_bcount; 697 biodone(bp); 698 return; 699 } 700 701 /* 702 * Place it in the queue of disk activities for this disk 703 */ 704 mtx_lock(&sc->xbd_io_lock); 705 706 xbd_enqueue_bio(sc, bp); 707 xbd_startio(sc); 708 709 mtx_unlock(&sc->xbd_io_lock); 710 return; 711} 712 713/*------------------------------ Ring Management -----------------------------*/ 714static int 715xbd_alloc_ring(struct xbd_softc *sc) 716{ 717 blkif_sring_t *sring; 718 uintptr_t sring_page_addr; 719 int error; 720 int i; 721 722 sring = malloc(sc->xbd_ring_pages * PAGE_SIZE, M_XENBLOCKFRONT, 723 M_NOWAIT|M_ZERO); 724 if (sring == NULL) { 725 xenbus_dev_fatal(sc->xbd_dev, ENOMEM, "allocating shared ring"); 726 return (ENOMEM); 727 } 728 SHARED_RING_INIT(sring); 729 FRONT_RING_INIT(&sc->xbd_ring, sring, sc->xbd_ring_pages * PAGE_SIZE); 730 731 for (i = 0, sring_page_addr = (uintptr_t)sring; 732 i < sc->xbd_ring_pages; 733 i++, sring_page_addr += PAGE_SIZE) { 734 735 error = xenbus_grant_ring(sc->xbd_dev, 736 (vtomach(sring_page_addr) >> PAGE_SHIFT), 737 &sc->xbd_ring_ref[i]); 738 if (error) { 739 xenbus_dev_fatal(sc->xbd_dev, error, 740 "granting ring_ref(%d)", i); 741 return (error); 742 } 743 } 744 if (sc->xbd_ring_pages == 1) { 745 error = xs_printf(XST_NIL, xenbus_get_node(sc->xbd_dev), 746 "ring-ref", "%u", sc->xbd_ring_ref[0]); 747 if (error) { 748 xenbus_dev_fatal(sc->xbd_dev, error, 749 "writing %s/ring-ref", 750 xenbus_get_node(sc->xbd_dev)); 751 return (error); 752 } 753 } else { 754 for (i = 0; i < sc->xbd_ring_pages; i++) { 755 char ring_ref_name[]= "ring_refXX"; 756 757 snprintf(ring_ref_name, sizeof(ring_ref_name), 758 "ring-ref%u", i); 759 error = xs_printf(XST_NIL, xenbus_get_node(sc->xbd_dev), 760 ring_ref_name, "%u", sc->xbd_ring_ref[i]); 761 if (error) { 762 xenbus_dev_fatal(sc->xbd_dev, error, 763 "writing %s/%s", 764 xenbus_get_node(sc->xbd_dev), 765 ring_ref_name); 766 return (error); 767 } 768 } 769 } 770 771 error = xen_intr_alloc_and_bind_local_port(sc->xbd_dev, 772 xenbus_get_otherend_id(sc->xbd_dev), NULL, xbd_int, sc, 773 INTR_TYPE_BIO | INTR_MPSAFE, &sc->xen_intr_handle); 774 if (error) { 775 xenbus_dev_fatal(sc->xbd_dev, error, 776 "xen_intr_alloc_and_bind_local_port failed"); 777 return (error); 778 } 779 780 return (0); 781} 782 783static void 784xbd_free_ring(struct xbd_softc *sc) 785{ 786 int i; 787 788 if (sc->xbd_ring.sring == NULL) 789 return; 790 791 for (i = 0; i < sc->xbd_ring_pages; i++) { 792 if (sc->xbd_ring_ref[i] != GRANT_REF_INVALID) { 793 gnttab_end_foreign_access_ref(sc->xbd_ring_ref[i]); 794 sc->xbd_ring_ref[i] = GRANT_REF_INVALID; 795 } 796 } 797 free(sc->xbd_ring.sring, M_XENBLOCKFRONT); 798 sc->xbd_ring.sring = NULL; 799} 800 801/*-------------------------- Initialization/Teardown -------------------------*/ 802static int 803xbd_feature_string(struct xbd_softc *sc, char *features, size_t len) 804{ 805 struct sbuf sb; 806 int feature_cnt; 807 808 sbuf_new(&sb, features, len, SBUF_FIXEDLEN); 809 810 feature_cnt = 0; 811 if ((sc->xbd_flags & XBDF_FLUSH) != 0) { 812 sbuf_printf(&sb, "flush"); 813 feature_cnt++; 814 } 815 816 if ((sc->xbd_flags & XBDF_BARRIER) != 0) { 817 if (feature_cnt != 0) 818 sbuf_printf(&sb, ", "); 819 sbuf_printf(&sb, "write_barrier"); 820 feature_cnt++; 821 } 822 823 (void) sbuf_finish(&sb); 824 return (sbuf_len(&sb)); 825} 826 827static int 828xbd_sysctl_features(SYSCTL_HANDLER_ARGS) 829{ 830 char features[80]; 831 struct xbd_softc *sc = arg1; 832 int error; 833 int len; 834 835 error = sysctl_wire_old_buffer(req, 0); 836 if (error != 0) 837 return (error); 838 839 len = xbd_feature_string(sc, features, sizeof(features)); 840 841 /* len is -1 on error, which will make the SYSCTL_OUT a no-op. */ 842 return (SYSCTL_OUT(req, features, len + 1/*NUL*/)); 843} 844 845static void 846xbd_setup_sysctl(struct xbd_softc *xbd) 847{ 848 struct sysctl_ctx_list *sysctl_ctx = NULL; 849 struct sysctl_oid *sysctl_tree = NULL; 850 struct sysctl_oid_list *children; 851 852 sysctl_ctx = device_get_sysctl_ctx(xbd->xbd_dev); 853 if (sysctl_ctx == NULL) 854 return; 855 856 sysctl_tree = device_get_sysctl_tree(xbd->xbd_dev); 857 if (sysctl_tree == NULL) 858 return; 859 860 children = SYSCTL_CHILDREN(sysctl_tree); 861 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 862 "max_requests", CTLFLAG_RD, &xbd->xbd_max_requests, -1, 863 "maximum outstanding requests (negotiated)"); 864 865 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 866 "max_request_segments", CTLFLAG_RD, 867 &xbd->xbd_max_request_segments, 0, 868 "maximum number of pages per requests (negotiated)"); 869 870 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 871 "max_request_size", CTLFLAG_RD, &xbd->xbd_max_request_size, 0, 872 "maximum size in bytes of a request (negotiated)"); 873 874 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 875 "ring_pages", CTLFLAG_RD, &xbd->xbd_ring_pages, 0, 876 "communication channel pages (negotiated)"); 877 878 SYSCTL_ADD_PROC(sysctl_ctx, children, OID_AUTO, 879 "features", CTLTYPE_STRING|CTLFLAG_RD, xbd, 0, 880 xbd_sysctl_features, "A", "protocol features (negotiated)"); 881} 882 883/* 884 * Translate Linux major/minor to an appropriate name and unit 885 * number. For HVM guests, this allows us to use the same drive names 886 * with blkfront as the emulated drives, easing transition slightly. 887 */ 888static void 889xbd_vdevice_to_unit(uint32_t vdevice, int *unit, const char **name) 890{ 891 static struct vdev_info { 892 int major; 893 int shift; 894 int base; 895 const char *name; 896 } info[] = { 897 {3, 6, 0, "ada"}, /* ide0 */ 898 {22, 6, 2, "ada"}, /* ide1 */ 899 {33, 6, 4, "ada"}, /* ide2 */ 900 {34, 6, 6, "ada"}, /* ide3 */ 901 {56, 6, 8, "ada"}, /* ide4 */ 902 {57, 6, 10, "ada"}, /* ide5 */ 903 {88, 6, 12, "ada"}, /* ide6 */ 904 {89, 6, 14, "ada"}, /* ide7 */ 905 {90, 6, 16, "ada"}, /* ide8 */ 906 {91, 6, 18, "ada"}, /* ide9 */ 907 908 {8, 4, 0, "da"}, /* scsi disk0 */ 909 {65, 4, 16, "da"}, /* scsi disk1 */ 910 {66, 4, 32, "da"}, /* scsi disk2 */ 911 {67, 4, 48, "da"}, /* scsi disk3 */ 912 {68, 4, 64, "da"}, /* scsi disk4 */ 913 {69, 4, 80, "da"}, /* scsi disk5 */ 914 {70, 4, 96, "da"}, /* scsi disk6 */ 915 {71, 4, 112, "da"}, /* scsi disk7 */ 916 {128, 4, 128, "da"}, /* scsi disk8 */ 917 {129, 4, 144, "da"}, /* scsi disk9 */ 918 {130, 4, 160, "da"}, /* scsi disk10 */ 919 {131, 4, 176, "da"}, /* scsi disk11 */ 920 {132, 4, 192, "da"}, /* scsi disk12 */ 921 {133, 4, 208, "da"}, /* scsi disk13 */ 922 {134, 4, 224, "da"}, /* scsi disk14 */ 923 {135, 4, 240, "da"}, /* scsi disk15 */ 924 925 {202, 4, 0, "xbd"}, /* xbd */ 926 927 {0, 0, 0, NULL}, 928 }; 929 int major = vdevice >> 8; 930 int minor = vdevice & 0xff; 931 int i; 932 933 if (vdevice & (1 << 28)) { 934 *unit = (vdevice & ((1 << 28) - 1)) >> 8; 935 *name = "xbd"; 936 return; 937 } 938 939 for (i = 0; info[i].major; i++) { 940 if (info[i].major == major) { 941 *unit = info[i].base + (minor >> info[i].shift); 942 *name = info[i].name; 943 return; 944 } 945 } 946 947 *unit = minor >> 4; 948 *name = "xbd"; 949} 950 951int 952xbd_instance_create(struct xbd_softc *sc, blkif_sector_t sectors, 953 int vdevice, uint16_t vdisk_info, unsigned long sector_size) 954{ 955 char features[80]; 956 int unit, error = 0; 957 const char *name; 958 959 xbd_vdevice_to_unit(vdevice, &unit, &name); 960 961 sc->xbd_unit = unit; 962 963 if (strcmp(name, "xbd") != 0) 964 device_printf(sc->xbd_dev, "attaching as %s%d\n", name, unit); 965 966 if (xbd_feature_string(sc, features, sizeof(features)) > 0) { 967 device_printf(sc->xbd_dev, "features: %s\n", 968 features); 969 } 970 971 sc->xbd_disk = disk_alloc(); 972 sc->xbd_disk->d_unit = sc->xbd_unit; 973 sc->xbd_disk->d_open = xbd_open; 974 sc->xbd_disk->d_close = xbd_close; 975 sc->xbd_disk->d_ioctl = xbd_ioctl; 976 sc->xbd_disk->d_strategy = xbd_strategy; 977 sc->xbd_disk->d_dump = xbd_dump; 978 sc->xbd_disk->d_name = name; 979 sc->xbd_disk->d_drv1 = sc; 980 sc->xbd_disk->d_sectorsize = sector_size; 981 982 sc->xbd_disk->d_mediasize = sectors * sector_size; 983 sc->xbd_disk->d_maxsize = sc->xbd_max_request_size; 984 sc->xbd_disk->d_flags = 0; 985 if ((sc->xbd_flags & (XBDF_FLUSH|XBDF_BARRIER)) != 0) { 986 sc->xbd_disk->d_flags |= DISKFLAG_CANFLUSHCACHE; 987 device_printf(sc->xbd_dev, 988 "synchronize cache commands enabled.\n"); 989 } 990 disk_create(sc->xbd_disk, DISK_VERSION); 991 992 return error; 993} 994 995static void 996xbd_free(struct xbd_softc *sc) 997{ 998 int i; 999 1000 /* Prevent new requests being issued until we fix things up. */ 1001 mtx_lock(&sc->xbd_io_lock); 1002 sc->xbd_state = XBD_STATE_DISCONNECTED; 1003 mtx_unlock(&sc->xbd_io_lock); 1004 1005 /* Free resources associated with old device channel. */ 1006 xbd_free_ring(sc); 1007 if (sc->xbd_shadow) { 1008 1009 for (i = 0; i < sc->xbd_max_requests; i++) { 1010 struct xbd_command *cm; 1011 1012 cm = &sc->xbd_shadow[i]; 1013 if (cm->cm_sg_refs != NULL) { 1014 free(cm->cm_sg_refs, M_XENBLOCKFRONT); 1015 cm->cm_sg_refs = NULL; 1016 } 1017 1018 bus_dmamap_destroy(sc->xbd_io_dmat, cm->cm_map); 1019 } 1020 free(sc->xbd_shadow, M_XENBLOCKFRONT); 1021 sc->xbd_shadow = NULL; 1022 1023 bus_dma_tag_destroy(sc->xbd_io_dmat); 1024 1025 xbd_initq_cm(sc, XBD_Q_FREE); 1026 xbd_initq_cm(sc, XBD_Q_READY); 1027 xbd_initq_cm(sc, XBD_Q_COMPLETE); 1028 } 1029 1030 xen_intr_unbind(&sc->xen_intr_handle); 1031 1032} 1033 1034/*--------------------------- State Change Handlers --------------------------*/ 1035static void 1036xbd_initialize(struct xbd_softc *sc) 1037{ 1038 const char *otherend_path; 1039 const char *node_path; 1040 uint32_t max_ring_page_order; 1041 int error; 1042 1043 if (xenbus_get_state(sc->xbd_dev) != XenbusStateInitialising) { 1044 /* Initialization has already been performed. */ 1045 return; 1046 } 1047 1048 /* 1049 * Protocol defaults valid even if negotiation for a 1050 * setting fails. 1051 */ 1052 max_ring_page_order = 0; 1053 sc->xbd_ring_pages = 1; 1054 sc->xbd_max_request_segments = BLKIF_MAX_SEGMENTS_PER_REQUEST; 1055 sc->xbd_max_request_size = 1056 XBD_SEGS_TO_SIZE(sc->xbd_max_request_segments); 1057 1058 /* 1059 * Protocol negotiation. 1060 * 1061 * \note xs_gather() returns on the first encountered error, so 1062 * we must use independant calls in order to guarantee 1063 * we don't miss information in a sparsly populated back-end 1064 * tree. 1065 * 1066 * \note xs_scanf() does not update variables for unmatched 1067 * fields. 1068 */ 1069 otherend_path = xenbus_get_otherend_path(sc->xbd_dev); 1070 node_path = xenbus_get_node(sc->xbd_dev); 1071 1072 /* Support both backend schemes for relaying ring page limits. */ 1073 (void)xs_scanf(XST_NIL, otherend_path, 1074 "max-ring-page-order", NULL, "%" PRIu32, 1075 &max_ring_page_order); 1076 sc->xbd_ring_pages = 1 << max_ring_page_order; 1077 (void)xs_scanf(XST_NIL, otherend_path, 1078 "max-ring-pages", NULL, "%" PRIu32, 1079 &sc->xbd_ring_pages); 1080 if (sc->xbd_ring_pages < 1) 1081 sc->xbd_ring_pages = 1; 1082 1083 if (sc->xbd_ring_pages > XBD_MAX_RING_PAGES) { 1084 device_printf(sc->xbd_dev, 1085 "Back-end specified ring-pages of %u " 1086 "limited to front-end limit of %u.\n", 1087 sc->xbd_ring_pages, XBD_MAX_RING_PAGES); 1088 sc->xbd_ring_pages = XBD_MAX_RING_PAGES; 1089 } 1090 1091 if (powerof2(sc->xbd_ring_pages) == 0) { 1092 uint32_t new_page_limit; 1093 1094 new_page_limit = 0x01 << (fls(sc->xbd_ring_pages) - 1); 1095 device_printf(sc->xbd_dev, 1096 "Back-end specified ring-pages of %u " 1097 "is not a power of 2. Limited to %u.\n", 1098 sc->xbd_ring_pages, new_page_limit); 1099 sc->xbd_ring_pages = new_page_limit; 1100 } 1101 1102 sc->xbd_max_requests = 1103 BLKIF_MAX_RING_REQUESTS(sc->xbd_ring_pages * PAGE_SIZE); 1104 if (sc->xbd_max_requests > XBD_MAX_REQUESTS) { 1105 device_printf(sc->xbd_dev, 1106 "Back-end specified max_requests of %u " 1107 "limited to front-end limit of %zu.\n", 1108 sc->xbd_max_requests, XBD_MAX_REQUESTS); 1109 sc->xbd_max_requests = XBD_MAX_REQUESTS; 1110 } 1111 1112 if (xbd_alloc_ring(sc) != 0) 1113 return; 1114 1115 /* Support both backend schemes for relaying ring page limits. */ 1116 if (sc->xbd_ring_pages > 1) { 1117 error = xs_printf(XST_NIL, node_path, 1118 "num-ring-pages","%u", 1119 sc->xbd_ring_pages); 1120 if (error) { 1121 xenbus_dev_fatal(sc->xbd_dev, error, 1122 "writing %s/num-ring-pages", 1123 node_path); 1124 return; 1125 } 1126 1127 error = xs_printf(XST_NIL, node_path, 1128 "ring-page-order", "%u", 1129 fls(sc->xbd_ring_pages) - 1); 1130 if (error) { 1131 xenbus_dev_fatal(sc->xbd_dev, error, 1132 "writing %s/ring-page-order", 1133 node_path); 1134 return; 1135 } 1136 } 1137 1138 error = xs_printf(XST_NIL, node_path, "event-channel", 1139 "%u", xen_intr_port(sc->xen_intr_handle)); 1140 if (error) { 1141 xenbus_dev_fatal(sc->xbd_dev, error, 1142 "writing %s/event-channel", 1143 node_path); 1144 return; 1145 } 1146 1147 error = xs_printf(XST_NIL, node_path, "protocol", 1148 "%s", XEN_IO_PROTO_ABI_NATIVE); 1149 if (error) { 1150 xenbus_dev_fatal(sc->xbd_dev, error, 1151 "writing %s/protocol", 1152 node_path); 1153 return; 1154 } 1155 1156 xenbus_set_state(sc->xbd_dev, XenbusStateInitialised); 1157} 1158 1159/* 1160 * Invoked when the backend is finally 'ready' (and has published 1161 * the details about the physical device - #sectors, size, etc). 1162 */ 1163static void 1164xbd_connect(struct xbd_softc *sc) 1165{ 1166 device_t dev = sc->xbd_dev; 1167 unsigned long sectors, sector_size; 1168 unsigned int binfo; 1169 int err, feature_barrier, feature_flush; 1170 int i; 1171 1172 if (sc->xbd_state == XBD_STATE_CONNECTED || 1173 sc->xbd_state == XBD_STATE_SUSPENDED) 1174 return; 1175 1176 DPRINTK("blkfront.c:connect:%s.\n", xenbus_get_otherend_path(dev)); 1177 1178 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev), 1179 "sectors", "%lu", §ors, 1180 "info", "%u", &binfo, 1181 "sector-size", "%lu", §or_size, 1182 NULL); 1183 if (err) { 1184 xenbus_dev_fatal(dev, err, 1185 "reading backend fields at %s", 1186 xenbus_get_otherend_path(dev)); 1187 return; 1188 } 1189 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev), 1190 "feature-barrier", "%lu", &feature_barrier, 1191 NULL); 1192 if (err == 0 && feature_barrier != 0) 1193 sc->xbd_flags |= XBDF_BARRIER; 1194 1195 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev), 1196 "feature-flush-cache", "%lu", &feature_flush, 1197 NULL); 1198 if (err == 0 && feature_flush != 0) 1199 sc->xbd_flags |= XBDF_FLUSH; 1200 1201 /* Allocate datastructures based on negotiated values. */ 1202 err = bus_dma_tag_create( 1203 bus_get_dma_tag(sc->xbd_dev), /* parent */ 1204 512, PAGE_SIZE, /* algnmnt, boundary */ 1205 BUS_SPACE_MAXADDR, /* lowaddr */ 1206 BUS_SPACE_MAXADDR, /* highaddr */ 1207 NULL, NULL, /* filter, filterarg */ 1208 sc->xbd_max_request_size, 1209 sc->xbd_max_request_segments, 1210 PAGE_SIZE, /* maxsegsize */ 1211 BUS_DMA_ALLOCNOW, /* flags */ 1212 busdma_lock_mutex, /* lockfunc */ 1213 &sc->xbd_io_lock, /* lockarg */ 1214 &sc->xbd_io_dmat); 1215 if (err != 0) { 1216 xenbus_dev_fatal(sc->xbd_dev, err, 1217 "Cannot allocate parent DMA tag\n"); 1218 return; 1219 } 1220 1221 /* Per-transaction data allocation. */ 1222 sc->xbd_shadow = malloc(sizeof(*sc->xbd_shadow) * sc->xbd_max_requests, 1223 M_XENBLOCKFRONT, M_NOWAIT|M_ZERO); 1224 if (sc->xbd_shadow == NULL) { 1225 bus_dma_tag_destroy(sc->xbd_io_dmat); 1226 xenbus_dev_fatal(sc->xbd_dev, ENOMEM, 1227 "Cannot allocate request structures\n"); 1228 return; 1229 } 1230 1231 for (i = 0; i < sc->xbd_max_requests; i++) { 1232 struct xbd_command *cm; 1233 1234 cm = &sc->xbd_shadow[i]; 1235 cm->cm_sg_refs = malloc( 1236 sizeof(grant_ref_t) * sc->xbd_max_request_segments, 1237 M_XENBLOCKFRONT, M_NOWAIT); 1238 if (cm->cm_sg_refs == NULL) 1239 break; 1240 cm->cm_id = i; 1241 cm->cm_flags = XBDCF_INITIALIZER; 1242 cm->cm_sc = sc; 1243 if (bus_dmamap_create(sc->xbd_io_dmat, 0, &cm->cm_map) != 0) 1244 break; 1245 xbd_free_command(cm); 1246 } 1247 1248 if (sc->xbd_disk == NULL) { 1249 device_printf(dev, "%juMB <%s> at %s", 1250 (uintmax_t) sectors / (1048576 / sector_size), 1251 device_get_desc(dev), 1252 xenbus_get_node(dev)); 1253 bus_print_child_footer(device_get_parent(dev), dev); 1254 1255 xbd_instance_create(sc, sectors, sc->xbd_vdevice, binfo, 1256 sector_size); 1257 } 1258 1259 (void)xenbus_set_state(dev, XenbusStateConnected); 1260 1261 /* Kick pending requests. */ 1262 mtx_lock(&sc->xbd_io_lock); 1263 sc->xbd_state = XBD_STATE_CONNECTED; 1264 xbd_startio(sc); 1265 sc->xbd_flags |= XBDF_READY; 1266 mtx_unlock(&sc->xbd_io_lock); 1267} 1268 1269/** 1270 * Handle the change of state of the backend to Closing. We must delete our 1271 * device-layer structures now, to ensure that writes are flushed through to 1272 * the backend. Once this is done, we can switch to Closed in 1273 * acknowledgement. 1274 */ 1275static void 1276xbd_closing(device_t dev) 1277{ 1278 struct xbd_softc *sc = device_get_softc(dev); 1279 1280 xenbus_set_state(dev, XenbusStateClosing); 1281 1282 DPRINTK("xbd_closing: %s removed\n", xenbus_get_node(dev)); 1283 1284 if (sc->xbd_disk != NULL) { 1285 disk_destroy(sc->xbd_disk); 1286 sc->xbd_disk = NULL; 1287 } 1288 1289 xenbus_set_state(dev, XenbusStateClosed); 1290} 1291 1292/*---------------------------- NewBus Entrypoints ----------------------------*/ 1293static int 1294xbd_probe(device_t dev) 1295{ 1296 if (strcmp(xenbus_get_type(dev), "vbd") != 0) 1297 return (ENXIO); 1298 1299 if (xen_hvm_domain()) { 1300 int error; 1301 char *type; 1302 1303 /* 1304 * When running in an HVM domain, IDE disk emulation is 1305 * disabled early in boot so that native drivers will 1306 * not see emulated hardware. However, CDROM device 1307 * emulation cannot be disabled. 1308 * 1309 * Through use of FreeBSD's vm_guest and xen_hvm_domain() 1310 * APIs, we could modify the native CDROM driver to fail its 1311 * probe when running under Xen. Unfortunatlely, the PV 1312 * CDROM support in XenServer (up through at least version 1313 * 6.2) isn't functional, so we instead rely on the emulated 1314 * CDROM instance, and fail to attach the PV one here in 1315 * the blkfront driver. 1316 */ 1317 error = xs_read(XST_NIL, xenbus_get_node(dev), 1318 "device-type", NULL, (void **) &type); 1319 if (error) 1320 return (ENXIO); 1321 1322 if (strncmp(type, "cdrom", 5) == 0) { 1323 free(type, M_XENSTORE); 1324 return (ENXIO); 1325 } 1326 free(type, M_XENSTORE); 1327 } 1328 1329 device_set_desc(dev, "Virtual Block Device"); 1330 device_quiet(dev); 1331 return (0); 1332} 1333 1334/* 1335 * Setup supplies the backend dir, virtual device. We place an event 1336 * channel and shared frame entries. We watch backend to wait if it's 1337 * ok. 1338 */ 1339static int 1340xbd_attach(device_t dev) 1341{ 1342 struct xbd_softc *sc; 1343 const char *name; 1344 uint32_t vdevice; 1345 int error; 1346 int i; 1347 int unit; 1348 1349 /* FIXME: Use dynamic device id if this is not set. */ 1350 error = xs_scanf(XST_NIL, xenbus_get_node(dev), 1351 "virtual-device", NULL, "%" PRIu32, &vdevice); 1352 if (error) 1353 error = xs_scanf(XST_NIL, xenbus_get_node(dev), 1354 "virtual-device-ext", NULL, "%" PRIu32, &vdevice); 1355 if (error) { 1356 xenbus_dev_fatal(dev, error, "reading virtual-device"); 1357 device_printf(dev, "Couldn't determine virtual device.\n"); 1358 return (error); 1359 } 1360 1361 xbd_vdevice_to_unit(vdevice, &unit, &name); 1362 if (!strcmp(name, "xbd")) 1363 device_set_unit(dev, unit); 1364 1365 sc = device_get_softc(dev); 1366 mtx_init(&sc->xbd_io_lock, "blkfront i/o lock", NULL, MTX_DEF); 1367 xbd_initqs(sc); 1368 for (i = 0; i < XBD_MAX_RING_PAGES; i++) 1369 sc->xbd_ring_ref[i] = GRANT_REF_INVALID; 1370 1371 sc->xbd_dev = dev; 1372 sc->xbd_vdevice = vdevice; 1373 sc->xbd_state = XBD_STATE_DISCONNECTED; 1374 1375 xbd_setup_sysctl(sc); 1376 1377 /* Wait for backend device to publish its protocol capabilities. */ 1378 xenbus_set_state(dev, XenbusStateInitialising); 1379 1380 return (0); 1381} 1382 1383static int 1384xbd_detach(device_t dev) 1385{ 1386 struct xbd_softc *sc = device_get_softc(dev); 1387 1388 DPRINTK("%s: %s removed\n", __func__, xenbus_get_node(dev)); 1389 1390 xbd_free(sc); 1391 mtx_destroy(&sc->xbd_io_lock); 1392 1393 return 0; 1394} 1395 1396static int 1397xbd_suspend(device_t dev) 1398{ 1399 struct xbd_softc *sc = device_get_softc(dev); 1400 int retval; 1401 int saved_state; 1402 1403 /* Prevent new requests being issued until we fix things up. */ 1404 mtx_lock(&sc->xbd_io_lock); 1405 saved_state = sc->xbd_state; 1406 sc->xbd_state = XBD_STATE_SUSPENDED; 1407 1408 /* Wait for outstanding I/O to drain. */ 1409 retval = 0; 1410 while (xbd_queue_length(sc, XBD_Q_BUSY) != 0) { 1411 if (msleep(&sc->xbd_cm_q[XBD_Q_BUSY], &sc->xbd_io_lock, 1412 PRIBIO, "blkf_susp", 30 * hz) == EWOULDBLOCK) { 1413 retval = EBUSY; 1414 break; 1415 } 1416 } 1417 mtx_unlock(&sc->xbd_io_lock); 1418 1419 if (retval != 0) 1420 sc->xbd_state = saved_state; 1421 1422 return (retval); 1423} 1424 1425static int 1426xbd_resume(device_t dev) 1427{ 1428 struct xbd_softc *sc = device_get_softc(dev); 1429 1430 DPRINTK("xbd_resume: %s\n", xenbus_get_node(dev)); 1431 1432 xbd_free(sc); 1433 xbd_initialize(sc); 1434 return (0); 1435} 1436 1437/** 1438 * Callback received when the backend's state changes. 1439 */ 1440static void 1441xbd_backend_changed(device_t dev, XenbusState backend_state) 1442{ 1443 struct xbd_softc *sc = device_get_softc(dev); 1444 1445 DPRINTK("backend_state=%d\n", backend_state); 1446 1447 switch (backend_state) { 1448 case XenbusStateUnknown: 1449 case XenbusStateInitialising: 1450 case XenbusStateReconfigured: 1451 case XenbusStateReconfiguring: 1452 case XenbusStateClosed: 1453 break; 1454 1455 case XenbusStateInitWait: 1456 case XenbusStateInitialised: 1457 xbd_initialize(sc); 1458 break; 1459 1460 case XenbusStateConnected: 1461 xbd_initialize(sc); 1462 xbd_connect(sc); 1463 break; 1464 1465 case XenbusStateClosing: 1466 if (sc->xbd_users > 0) 1467 xenbus_dev_error(dev, -EBUSY, 1468 "Device in use; refusing to close"); 1469 else 1470 xbd_closing(dev); 1471 break; 1472 } 1473} 1474 1475/*---------------------------- NewBus Registration ---------------------------*/ 1476static device_method_t xbd_methods[] = { 1477 /* Device interface */ 1478 DEVMETHOD(device_probe, xbd_probe), 1479 DEVMETHOD(device_attach, xbd_attach), 1480 DEVMETHOD(device_detach, xbd_detach), 1481 DEVMETHOD(device_shutdown, bus_generic_shutdown), 1482 DEVMETHOD(device_suspend, xbd_suspend), 1483 DEVMETHOD(device_resume, xbd_resume), 1484 1485 /* Xenbus interface */ 1486 DEVMETHOD(xenbus_otherend_changed, xbd_backend_changed), 1487 1488 { 0, 0 } 1489}; 1490 1491static driver_t xbd_driver = { 1492 "xbd", 1493 xbd_methods, 1494 sizeof(struct xbd_softc), 1495}; 1496devclass_t xbd_devclass; 1497 1498DRIVER_MODULE(xbd, xenbusb_front, xbd_driver, xbd_devclass, 0, 0); 1499