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 <machine/_inttypes.h> 55 #include <machine/xen/xen-os.h> 56 #include <machine/xen/xenvar.h> 57 #include <machine/xen/xenfunc.h> 58 59 #include <xen/hypervisor.h> 60 #include <xen/xen_intr.h> 61 #include <xen/evtchn.h> 62 #include <xen/gnttab.h> 63 #include <xen/interface/grant_table.h> 64 #include <xen/interface/io/protocols.h> 65 #include <xen/xenbus/xenbusvar.h> 66 67 #include <geom/geom_disk.h> 68 69 #include <dev/xen/blkfront/block.h> 70 71 #include "xenbus_if.h" 72 73 /*--------------------------- Forward Declarations ---------------------------*/ 74 static void xbd_closing(device_t); 75 static void xbd_startio(struct xbd_softc *sc); 76 77 /*---------------------------------- Macros ----------------------------------*/ 78 #if 0 79 #define DPRINTK(fmt, args...) printf("[XEN] %s:%d: " fmt ".\n", __func__, __LINE__, ##args) 80 #else 81 #define DPRINTK(fmt, args...) 82 #endif 83 84 #define XBD_SECTOR_SHFT 9 85 86 /*---------------------------- Global Static Data ----------------------------*/ 87 static MALLOC_DEFINE(M_XENBLOCKFRONT, "xbd", "Xen Block Front driver data"); 88 89 /*---------------------------- Command Processing ----------------------------*/ 90 static void 91 xbd_freeze(struct xbd_softc *sc, xbd_flag_t xbd_flag) 92 { 93 if (xbd_flag != XBDF_NONE && (sc->xbd_flags & xbd_flag) != 0) 94 return; 95 96 sc->xbd_flags |= xbd_flag; 97 sc->xbd_qfrozen_cnt++; 98 } 99 100 static void 101 xbd_thaw(struct xbd_softc *sc, xbd_flag_t xbd_flag) 102 { 103 if (xbd_flag != XBDF_NONE && (sc->xbd_flags & xbd_flag) == 0) 104 return; 105 106 if (sc->xbd_qfrozen_cnt == 0) 107 panic("%s: Thaw with flag 0x%x while not frozen.", 108 __func__, xbd_flag); 109 110 sc->xbd_flags &= ~xbd_flag; 111 sc->xbd_qfrozen_cnt--; 112 } 113 114 static void 115 xbd_cm_freeze(struct xbd_softc *sc, struct xbd_command *cm, xbdc_flag_t cm_flag) 116 { 117 if ((cm->cm_flags & XBDCF_FROZEN) != 0) 118 return; 119 120 cm->cm_flags |= XBDCF_FROZEN|cm_flag; 121 xbd_freeze(sc, XBDF_NONE); 122 } 123 124 static void 125 xbd_cm_thaw(struct xbd_softc *sc, struct xbd_command *cm) 126 { 127 if ((cm->cm_flags & XBDCF_FROZEN) == 0) 128 return; 129 130 cm->cm_flags &= ~XBDCF_FROZEN; 131 xbd_thaw(sc, XBDF_NONE); 132 } 133 134 static inline void 135 xbd_flush_requests(struct xbd_softc *sc) 136 { 137 int notify; 138 139 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&sc->xbd_ring, notify); 140 141 if (notify) 142 notify_remote_via_irq(sc->xbd_irq); 143 } 144 145 static void 146 xbd_free_command(struct xbd_command *cm) 147 { 148 149 KASSERT((cm->cm_flags & XBDCF_Q_MASK) == XBD_Q_NONE, 150 ("Freeing command that is still on queue %d.", 151 cm->cm_flags & XBDCF_Q_MASK)); 152 153 cm->cm_flags = XBDCF_INITIALIZER; 154 cm->cm_bp = NULL; 155 cm->cm_complete = NULL; 156 xbd_enqueue_cm(cm, XBD_Q_FREE); 157 xbd_thaw(cm->cm_sc, XBDF_CM_SHORTAGE); 158 } 159 160 static void 161 xbd_queue_cb(void *arg, bus_dma_segment_t *segs, int nsegs, int error) 162 { 163 struct xbd_softc *sc; 164 struct xbd_command *cm; 165 blkif_request_t *ring_req; 166 struct blkif_request_segment *sg; 167 struct blkif_request_segment *last_block_sg; 168 grant_ref_t *sg_ref; 169 vm_paddr_t buffer_ma; 170 uint64_t fsect, lsect; 171 int ref; 172 int op; 173 int block_segs; 174 175 cm = arg; 176 sc = cm->cm_sc; 177 178 if (error) { 179 printf("error %d in xbd_queue_cb\n", error); 180 cm->cm_bp->bio_error = EIO; 181 biodone(cm->cm_bp); 182 xbd_free_command(cm); 183 return; 184 } 185 186 /* Fill out a communications ring structure. */ 187 ring_req = RING_GET_REQUEST(&sc->xbd_ring, sc->xbd_ring.req_prod_pvt); 188 sc->xbd_ring.req_prod_pvt++; 189 ring_req->id = cm->cm_id; 190 ring_req->operation = cm->cm_operation; 191 ring_req->sector_number = cm->cm_sector_number; 192 ring_req->handle = (blkif_vdev_t)(uintptr_t)sc->xbd_disk; 193 ring_req->nr_segments = nsegs; 194 cm->cm_nseg = nsegs; 195 196 block_segs = MIN(nsegs, BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK); 197 sg = ring_req->seg; 198 last_block_sg = sg + block_segs; 199 sg_ref = cm->cm_sg_refs; 200 201 while (1) { 202 203 while (sg < last_block_sg) { 204 buffer_ma = segs->ds_addr; 205 fsect = (buffer_ma & PAGE_MASK) >> XBD_SECTOR_SHFT; 206 lsect = fsect + (segs->ds_len >> XBD_SECTOR_SHFT) - 1; 207 208 KASSERT(lsect <= 7, ("XEN disk driver data cannot " 209 "cross a page boundary")); 210 211 /* install a grant reference. */ 212 ref = gnttab_claim_grant_reference(&cm->cm_gref_head); 213 214 /* 215 * GNTTAB_LIST_END == 0xffffffff, but it is private 216 * to gnttab.c. 217 */ 218 KASSERT(ref != ~0, ("grant_reference failed")); 219 220 gnttab_grant_foreign_access_ref( 221 ref, 222 xenbus_get_otherend_id(sc->xbd_dev), 223 buffer_ma >> PAGE_SHIFT, 224 ring_req->operation == BLKIF_OP_WRITE); 225 226 *sg_ref = ref; 227 *sg = (struct blkif_request_segment) { 228 .gref = ref, 229 .first_sect = fsect, 230 .last_sect = lsect 231 }; 232 sg++; 233 sg_ref++; 234 segs++; 235 nsegs--; 236 } 237 block_segs = MIN(nsegs, BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK); 238 if (block_segs == 0) 239 break; 240 241 sg = BLKRING_GET_SEG_BLOCK(&sc->xbd_ring, 242 sc->xbd_ring.req_prod_pvt); 243 sc->xbd_ring.req_prod_pvt++; 244 last_block_sg = sg + block_segs; 245 } 246 247 if (cm->cm_operation == BLKIF_OP_READ) 248 op = BUS_DMASYNC_PREREAD; 249 else if (cm->cm_operation == BLKIF_OP_WRITE) 250 op = BUS_DMASYNC_PREWRITE; 251 else 252 op = 0; 253 bus_dmamap_sync(sc->xbd_io_dmat, cm->cm_map, op); 254 255 gnttab_free_grant_references(cm->cm_gref_head); 256 257 xbd_enqueue_cm(cm, XBD_Q_BUSY); 258 259 /* 260 * If bus dma had to asynchronously call us back to dispatch 261 * this command, we are no longer executing in the context of 262 * xbd_startio(). Thus we cannot rely on xbd_startio()'s call to 263 * xbd_flush_requests() to publish this command to the backend 264 * along with any other commands that it could batch. 265 */ 266 if ((cm->cm_flags & XBDCF_ASYNC_MAPPING) != 0) 267 xbd_flush_requests(sc); 268 269 return; 270 } 271 272 static int 273 xbd_queue_request(struct xbd_softc *sc, struct xbd_command *cm) 274 { 275 int error; 276 277 error = bus_dmamap_load(sc->xbd_io_dmat, cm->cm_map, cm->cm_data, 278 cm->cm_datalen, xbd_queue_cb, cm, 0); 279 if (error == EINPROGRESS) { 280 /* 281 * Maintain queuing order by freezing the queue. The next 282 * command may not require as many resources as the command 283 * we just attempted to map, so we can't rely on bus dma 284 * blocking for it too. 285 */ 286 xbd_cm_freeze(sc, cm, XBDCF_ASYNC_MAPPING); 287 return (0); 288 } 289 290 return (error); 291 } 292 293 static void 294 xbd_restart_queue_callback(void *arg) 295 { 296 struct xbd_softc *sc = arg; 297 298 mtx_lock(&sc->xbd_io_lock); 299 300 xbd_thaw(sc, XBDF_GNT_SHORTAGE); 301 302 xbd_startio(sc); 303 304 mtx_unlock(&sc->xbd_io_lock); 305 } 306 307 static struct xbd_command * 308 xbd_bio_command(struct xbd_softc *sc) 309 { 310 struct xbd_command *cm; 311 struct bio *bp; 312 313 if (unlikely(sc->xbd_state != XBD_STATE_CONNECTED)) 314 return (NULL); 315 316 bp = xbd_dequeue_bio(sc); 317 if (bp == NULL) 318 return (NULL); 319 320 if ((cm = xbd_dequeue_cm(sc, XBD_Q_FREE)) == NULL) { 321 xbd_freeze(sc, XBDF_CM_SHORTAGE); 322 xbd_requeue_bio(sc, bp); 323 return (NULL); 324 } 325 326 if (gnttab_alloc_grant_references(sc->xbd_max_request_segments, 327 &cm->cm_gref_head) != 0) { 328 gnttab_request_free_callback(&sc->xbd_callback, 329 xbd_restart_queue_callback, sc, 330 sc->xbd_max_request_segments); 331 xbd_freeze(sc, XBDF_GNT_SHORTAGE); 332 xbd_requeue_bio(sc, bp); 333 xbd_enqueue_cm(cm, XBD_Q_FREE); 334 return (NULL); 335 } 336 337 cm->cm_bp = bp; 338 cm->cm_data = bp->bio_data; 339 cm->cm_datalen = bp->bio_bcount; 340 cm->cm_sector_number = (blkif_sector_t)bp->bio_pblkno; 341 342 switch (bp->bio_cmd) { 343 case BIO_READ: 344 cm->cm_operation = BLKIF_OP_READ; 345 break; 346 case BIO_WRITE: 347 cm->cm_operation = BLKIF_OP_WRITE; 348 if ((bp->bio_flags & BIO_ORDERED) != 0) { 349 if ((sc->xbd_flags & XBDF_BARRIER) != 0) { 350 cm->cm_operation = BLKIF_OP_WRITE_BARRIER; 351 } else { 352 /* 353 * Single step this command. 354 */ 355 cm->cm_flags |= XBDCF_Q_FREEZE; 356 if (xbd_queue_length(sc, XBD_Q_BUSY) != 0) { 357 /* 358 * Wait for in-flight requests to 359 * finish. 360 */ 361 xbd_freeze(sc, XBDF_WAIT_IDLE); 362 xbd_requeue_cm(cm, XBD_Q_READY); 363 return (NULL); 364 } 365 } 366 } 367 break; 368 case BIO_FLUSH: 369 if ((sc->xbd_flags & XBDF_FLUSH) != 0) 370 cm->cm_operation = BLKIF_OP_FLUSH_DISKCACHE; 371 else if ((sc->xbd_flags & XBDF_BARRIER) != 0) 372 cm->cm_operation = BLKIF_OP_WRITE_BARRIER; 373 else 374 panic("flush request, but no flush support available"); 375 break; 376 default: 377 panic("unknown bio command %d", bp->bio_cmd); 378 } 379 380 return (cm); 381 } 382 383 /* 384 * Dequeue buffers and place them in the shared communication ring. 385 * Return when no more requests can be accepted or all buffers have 386 * been queued. 387 * 388 * Signal XEN once the ring has been filled out. 389 */ 390 static void 391 xbd_startio(struct xbd_softc *sc) 392 { 393 struct xbd_command *cm; 394 int error, queued = 0; 395 396 mtx_assert(&sc->xbd_io_lock, MA_OWNED); 397 398 if (sc->xbd_state != XBD_STATE_CONNECTED) 399 return; 400 401 while (RING_FREE_REQUESTS(&sc->xbd_ring) >= 402 sc->xbd_max_request_blocks) { 403 if (sc->xbd_qfrozen_cnt != 0) 404 break; 405 406 cm = xbd_dequeue_cm(sc, XBD_Q_READY); 407 408 if (cm == NULL) 409 cm = xbd_bio_command(sc); 410 411 if (cm == NULL) 412 break; 413 414 if ((cm->cm_flags & XBDCF_Q_FREEZE) != 0) { 415 /* 416 * Single step command. Future work is 417 * held off until this command completes. 418 */ 419 xbd_cm_freeze(sc, cm, XBDCF_Q_FREEZE); 420 } 421 422 if ((error = xbd_queue_request(sc, cm)) != 0) { 423 printf("xbd_queue_request returned %d\n", error); 424 break; 425 } 426 queued++; 427 } 428 429 if (queued != 0) 430 xbd_flush_requests(sc); 431 } 432 433 static void 434 xbd_bio_complete(struct xbd_softc *sc, struct xbd_command *cm) 435 { 436 struct bio *bp; 437 438 bp = cm->cm_bp; 439 440 if (unlikely(cm->cm_status != BLKIF_RSP_OKAY)) { 441 disk_err(bp, "disk error" , -1, 0); 442 printf(" status: %x\n", cm->cm_status); 443 bp->bio_flags |= BIO_ERROR; 444 } 445 446 if (bp->bio_flags & BIO_ERROR) 447 bp->bio_error = EIO; 448 else 449 bp->bio_resid = 0; 450 451 xbd_free_command(cm); 452 biodone(bp); 453 } 454 455 static int 456 xbd_completion(struct xbd_command *cm) 457 { 458 gnttab_end_foreign_access_references(cm->cm_nseg, cm->cm_sg_refs); 459 return (BLKIF_SEGS_TO_BLOCKS(cm->cm_nseg)); 460 } 461 462 static void 463 xbd_int(void *xsc) 464 { 465 struct xbd_softc *sc = xsc; 466 struct xbd_command *cm; 467 blkif_response_t *bret; 468 RING_IDX i, rp; 469 int op; 470 471 mtx_lock(&sc->xbd_io_lock); 472 473 if (unlikely(sc->xbd_state == XBD_STATE_DISCONNECTED)) { 474 mtx_unlock(&sc->xbd_io_lock); 475 return; 476 } 477 478 again: 479 rp = sc->xbd_ring.sring->rsp_prod; 480 rmb(); /* Ensure we see queued responses up to 'rp'. */ 481 482 for (i = sc->xbd_ring.rsp_cons; i != rp;) { 483 bret = RING_GET_RESPONSE(&sc->xbd_ring, i); 484 cm = &sc->xbd_shadow[bret->id]; 485 486 xbd_remove_cm(cm, XBD_Q_BUSY); 487 i += xbd_completion(cm); 488 489 if (cm->cm_operation == BLKIF_OP_READ) 490 op = BUS_DMASYNC_POSTREAD; 491 else if (cm->cm_operation == BLKIF_OP_WRITE || 492 cm->cm_operation == BLKIF_OP_WRITE_BARRIER) 493 op = BUS_DMASYNC_POSTWRITE; 494 else 495 op = 0; 496 bus_dmamap_sync(sc->xbd_io_dmat, cm->cm_map, op); 497 bus_dmamap_unload(sc->xbd_io_dmat, cm->cm_map); 498 499 /* 500 * Release any hold this command has on future command 501 * dispatch. 502 */ 503 xbd_cm_thaw(sc, cm); 504 505 /* 506 * Directly call the i/o complete routine to save an 507 * an indirection in the common case. 508 */ 509 cm->cm_status = bret->status; 510 if (cm->cm_bp) 511 xbd_bio_complete(sc, cm); 512 else if (cm->cm_complete != NULL) 513 cm->cm_complete(cm); 514 else 515 xbd_free_command(cm); 516 } 517 518 sc->xbd_ring.rsp_cons = i; 519 520 if (i != sc->xbd_ring.req_prod_pvt) { 521 int more_to_do; 522 RING_FINAL_CHECK_FOR_RESPONSES(&sc->xbd_ring, more_to_do); 523 if (more_to_do) 524 goto again; 525 } else { 526 sc->xbd_ring.sring->rsp_event = i + 1; 527 } 528 529 if (xbd_queue_length(sc, XBD_Q_BUSY) == 0) 530 xbd_thaw(sc, XBDF_WAIT_IDLE); 531 532 xbd_startio(sc); 533 534 if (unlikely(sc->xbd_state == XBD_STATE_SUSPENDED)) 535 wakeup(&sc->xbd_cm_q[XBD_Q_BUSY]); 536 537 mtx_unlock(&sc->xbd_io_lock); 538 } 539 540 /*------------------------------- Dump Support -------------------------------*/ 541 /** 542 * Quiesce the disk writes for a dump file before allowing the next buffer. 543 */ 544 static void 545 xbd_quiesce(struct xbd_softc *sc) 546 { 547 int mtd; 548 549 // While there are outstanding requests 550 while (xbd_queue_length(sc, XBD_Q_BUSY) != 0) { 551 RING_FINAL_CHECK_FOR_RESPONSES(&sc->xbd_ring, mtd); 552 if (mtd) { 553 /* Recieved request completions, update queue. */ 554 xbd_int(sc); 555 } 556 if (xbd_queue_length(sc, XBD_Q_BUSY) != 0) { 557 /* 558 * Still pending requests, wait for the disk i/o 559 * to complete. 560 */ 561 HYPERVISOR_yield(); 562 } 563 } 564 } 565 566 /* Kernel dump function for a paravirtualized disk device */ 567 static void 568 xbd_dump_complete(struct xbd_command *cm) 569 { 570 571 xbd_enqueue_cm(cm, XBD_Q_COMPLETE); 572 } 573 574 static int 575 xbd_dump(void *arg, void *virtual, vm_offset_t physical, off_t offset, 576 size_t length) 577 { 578 struct disk *dp = arg; 579 struct xbd_softc *sc = dp->d_drv1; 580 struct xbd_command *cm; 581 size_t chunk; 582 int sbp; 583 int rc = 0; 584 585 if (length <= 0) 586 return (rc); 587 588 xbd_quiesce(sc); /* All quiet on the western front. */ 589 590 /* 591 * If this lock is held, then this module is failing, and a 592 * successful kernel dump is highly unlikely anyway. 593 */ 594 mtx_lock(&sc->xbd_io_lock); 595 596 /* Split the 64KB block as needed */ 597 for (sbp=0; length > 0; sbp++) { 598 cm = xbd_dequeue_cm(sc, XBD_Q_FREE); 599 if (cm == NULL) { 600 mtx_unlock(&sc->xbd_io_lock); 601 device_printf(sc->xbd_dev, "dump: no more commands?\n"); 602 return (EBUSY); 603 } 604 605 if (gnttab_alloc_grant_references(sc->xbd_max_request_segments, 606 &cm->cm_gref_head) != 0) { 607 xbd_free_command(cm); 608 mtx_unlock(&sc->xbd_io_lock); 609 device_printf(sc->xbd_dev, "no more grant allocs?\n"); 610 return (EBUSY); 611 } 612 613 chunk = length > sc->xbd_max_request_size ? 614 sc->xbd_max_request_size : length; 615 cm->cm_data = virtual; 616 cm->cm_datalen = chunk; 617 cm->cm_operation = BLKIF_OP_WRITE; 618 cm->cm_sector_number = offset / dp->d_sectorsize; 619 cm->cm_complete = xbd_dump_complete; 620 621 xbd_enqueue_cm(cm, XBD_Q_READY); 622 623 length -= chunk; 624 offset += chunk; 625 virtual = (char *) virtual + chunk; 626 } 627 628 /* Tell DOM0 to do the I/O */ 629 xbd_startio(sc); 630 mtx_unlock(&sc->xbd_io_lock); 631 632 /* Poll for the completion. */ 633 xbd_quiesce(sc); /* All quite on the eastern front */ 634 635 /* If there were any errors, bail out... */ 636 while ((cm = xbd_dequeue_cm(sc, XBD_Q_COMPLETE)) != NULL) { 637 if (cm->cm_status != BLKIF_RSP_OKAY) { 638 device_printf(sc->xbd_dev, 639 "Dump I/O failed at sector %jd\n", 640 cm->cm_sector_number); 641 rc = EIO; 642 } 643 xbd_free_command(cm); 644 } 645 646 return (rc); 647 } 648 649 /*----------------------------- Disk Entrypoints -----------------------------*/ 650 static int 651 xbd_open(struct disk *dp) 652 { 653 struct xbd_softc *sc = dp->d_drv1; 654 655 if (sc == NULL) { 656 printf("xb%d: not found", sc->xbd_unit); 657 return (ENXIO); 658 } 659 660 sc->xbd_flags |= XBDF_OPEN; 661 sc->xbd_users++; 662 return (0); 663 } 664 665 static int 666 xbd_close(struct disk *dp) 667 { 668 struct xbd_softc *sc = dp->d_drv1; 669 670 if (sc == NULL) 671 return (ENXIO); 672 sc->xbd_flags &= ~XBDF_OPEN; 673 if (--(sc->xbd_users) == 0) { 674 /* 675 * Check whether we have been instructed to close. We will 676 * have ignored this request initially, as the device was 677 * still mounted. 678 */ 679 if (xenbus_get_otherend_state(sc->xbd_dev) == 680 XenbusStateClosing) 681 xbd_closing(sc->xbd_dev); 682 } 683 return (0); 684 } 685 686 static int 687 xbd_ioctl(struct disk *dp, u_long cmd, void *addr, int flag, struct thread *td) 688 { 689 struct xbd_softc *sc = dp->d_drv1; 690 691 if (sc == NULL) 692 return (ENXIO); 693 694 return (ENOTTY); 695 } 696 697 /* 698 * Read/write routine for a buffer. Finds the proper unit, place it on 699 * the sortq and kick the controller. 700 */ 701 static void 702 xbd_strategy(struct bio *bp) 703 { 704 struct xbd_softc *sc = bp->bio_disk->d_drv1; 705 706 /* bogus disk? */ 707 if (sc == NULL) { 708 bp->bio_error = EINVAL; 709 bp->bio_flags |= BIO_ERROR; 710 bp->bio_resid = bp->bio_bcount; 711 biodone(bp); 712 return; 713 } 714 715 /* 716 * Place it in the queue of disk activities for this disk 717 */ 718 mtx_lock(&sc->xbd_io_lock); 719 720 xbd_enqueue_bio(sc, bp); 721 xbd_startio(sc); 722 723 mtx_unlock(&sc->xbd_io_lock); 724 return; 725 } 726 727 /*------------------------------ Ring Management -----------------------------*/ 728 static int 729 xbd_alloc_ring(struct xbd_softc *sc) 730 { 731 blkif_sring_t *sring; 732 uintptr_t sring_page_addr; 733 int error; 734 int i; 735 736 sring = malloc(sc->xbd_ring_pages * PAGE_SIZE, M_XENBLOCKFRONT, 737 M_NOWAIT|M_ZERO); 738 if (sring == NULL) { 739 xenbus_dev_fatal(sc->xbd_dev, ENOMEM, "allocating shared ring"); 740 return (ENOMEM); 741 } 742 SHARED_RING_INIT(sring); 743 FRONT_RING_INIT(&sc->xbd_ring, sring, sc->xbd_ring_pages * PAGE_SIZE); 744 745 for (i = 0, sring_page_addr = (uintptr_t)sring; 746 i < sc->xbd_ring_pages; 747 i++, sring_page_addr += PAGE_SIZE) { 748 749 error = xenbus_grant_ring(sc->xbd_dev, 750 (vtomach(sring_page_addr) >> PAGE_SHIFT), 751 &sc->xbd_ring_ref[i]); 752 if (error) { 753 xenbus_dev_fatal(sc->xbd_dev, error, 754 "granting ring_ref(%d)", i); 755 return (error); 756 } 757 } 758 if (sc->xbd_ring_pages == 1) { 759 error = xs_printf(XST_NIL, xenbus_get_node(sc->xbd_dev), 760 "ring-ref", "%u", sc->xbd_ring_ref[0]); 761 if (error) { 762 xenbus_dev_fatal(sc->xbd_dev, error, 763 "writing %s/ring-ref", 764 xenbus_get_node(sc->xbd_dev)); 765 return (error); 766 } 767 } else { 768 for (i = 0; i < sc->xbd_ring_pages; i++) { 769 char ring_ref_name[]= "ring_refXX"; 770 771 snprintf(ring_ref_name, sizeof(ring_ref_name), 772 "ring-ref%u", i); 773 error = xs_printf(XST_NIL, xenbus_get_node(sc->xbd_dev), 774 ring_ref_name, "%u", sc->xbd_ring_ref[i]); 775 if (error) { 776 xenbus_dev_fatal(sc->xbd_dev, error, 777 "writing %s/%s", 778 xenbus_get_node(sc->xbd_dev), 779 ring_ref_name); 780 return (error); 781 } 782 } 783 } 784 785 error = bind_listening_port_to_irqhandler( 786 xenbus_get_otherend_id(sc->xbd_dev), 787 "xbd", (driver_intr_t *)xbd_int, sc, 788 INTR_TYPE_BIO | INTR_MPSAFE, &sc->xbd_irq); 789 if (error) { 790 xenbus_dev_fatal(sc->xbd_dev, error, 791 "bind_evtchn_to_irqhandler failed"); 792 return (error); 793 } 794 795 return (0); 796 } 797 798 static void 799 xbd_free_ring(struct xbd_softc *sc) 800 { 801 int i; 802 803 if (sc->xbd_ring.sring == NULL) 804 return; 805 806 for (i = 0; i < sc->xbd_ring_pages; i++) { 807 if (sc->xbd_ring_ref[i] != GRANT_REF_INVALID) { 808 gnttab_end_foreign_access_ref(sc->xbd_ring_ref[i]); 809 sc->xbd_ring_ref[i] = GRANT_REF_INVALID; 810 } 811 } 812 free(sc->xbd_ring.sring, M_XENBLOCKFRONT); 813 sc->xbd_ring.sring = NULL; 814 } 815 816 /*-------------------------- Initialization/Teardown -------------------------*/ 817 static int 818 xbd_feature_string(struct xbd_softc *sc, char *features, size_t len) 819 { 820 struct sbuf sb; 821 int feature_cnt; 822 823 sbuf_new(&sb, features, len, SBUF_FIXEDLEN); 824 825 feature_cnt = 0; 826 if ((sc->xbd_flags & XBDF_FLUSH) != 0) { 827 sbuf_printf(&sb, "flush"); 828 feature_cnt++; 829 } 830 831 if ((sc->xbd_flags & XBDF_BARRIER) != 0) { 832 if (feature_cnt != 0) 833 sbuf_printf(&sb, ", "); 834 sbuf_printf(&sb, "write_barrier"); 835 feature_cnt++; 836 } 837 838 (void) sbuf_finish(&sb); 839 return (sbuf_len(&sb)); 840 } 841 842 static int 843 xbd_sysctl_features(SYSCTL_HANDLER_ARGS) 844 { 845 char features[80]; 846 struct xbd_softc *sc = arg1; 847 int error; 848 int len; 849 850 error = sysctl_wire_old_buffer(req, 0); 851 if (error != 0) 852 return (error); 853 854 len = xbd_feature_string(sc, features, sizeof(features)); 855 856 /* len is -1 on error, which will make the SYSCTL_OUT a no-op. */ 857 return (SYSCTL_OUT(req, features, len + 1/*NUL*/)); 858 } 859 860 static void 861 xbd_setup_sysctl(struct xbd_softc *xbd) 862 { 863 struct sysctl_ctx_list *sysctl_ctx = NULL; 864 struct sysctl_oid *sysctl_tree = NULL; 865 struct sysctl_oid_list *children; 866 867 sysctl_ctx = device_get_sysctl_ctx(xbd->xbd_dev); 868 if (sysctl_ctx == NULL) 869 return; 870 871 sysctl_tree = device_get_sysctl_tree(xbd->xbd_dev); 872 if (sysctl_tree == NULL) 873 return; 874 875 children = SYSCTL_CHILDREN(sysctl_tree); 876 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 877 "max_requests", CTLFLAG_RD, &xbd->xbd_max_requests, -1, 878 "maximum outstanding requests (negotiated)"); 879 880 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 881 "max_requests", CTLFLAG_RD, &xbd->xbd_max_requests, -1, 882 "maximum outstanding requests (negotiated)"); 883 884 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 885 "max_request_segments", CTLFLAG_RD, 886 &xbd->xbd_max_request_segments, 0, 887 "maximum number of pages per requests (negotiated)"); 888 889 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 890 "max_request_size", CTLFLAG_RD, &xbd->xbd_max_request_size, 0, 891 "maximum size in bytes of a request (negotiated)"); 892 893 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 894 "ring_pages", CTLFLAG_RD, &xbd->xbd_ring_pages, 0, 895 "communication channel pages (negotiated)"); 896 897 SYSCTL_ADD_PROC(sysctl_ctx, children, OID_AUTO, 898 "features", CTLTYPE_STRING|CTLFLAG_RD, xbd, 0, 899 xbd_sysctl_features, "A", "protocol features (negotiated)"); 900 } 901 902 /* 903 * Translate Linux major/minor to an appropriate name and unit 904 * number. For HVM guests, this allows us to use the same drive names 905 * with blkfront as the emulated drives, easing transition slightly. 906 */ 907 static void 908 xbd_vdevice_to_unit(uint32_t vdevice, int *unit, const char **name) 909 { 910 static struct vdev_info { 911 int major; 912 int shift; 913 int base; 914 const char *name; 915 } info[] = { 916 {3, 6, 0, "ada"}, /* ide0 */ 917 {22, 6, 2, "ada"}, /* ide1 */ 918 {33, 6, 4, "ada"}, /* ide2 */ 919 {34, 6, 6, "ada"}, /* ide3 */ 920 {56, 6, 8, "ada"}, /* ide4 */ 921 {57, 6, 10, "ada"}, /* ide5 */ 922 {88, 6, 12, "ada"}, /* ide6 */ 923 {89, 6, 14, "ada"}, /* ide7 */ 924 {90, 6, 16, "ada"}, /* ide8 */ 925 {91, 6, 18, "ada"}, /* ide9 */ 926 927 {8, 4, 0, "da"}, /* scsi disk0 */ 928 {65, 4, 16, "da"}, /* scsi disk1 */ 929 {66, 4, 32, "da"}, /* scsi disk2 */ 930 {67, 4, 48, "da"}, /* scsi disk3 */ 931 {68, 4, 64, "da"}, /* scsi disk4 */ 932 {69, 4, 80, "da"}, /* scsi disk5 */ 933 {70, 4, 96, "da"}, /* scsi disk6 */ 934 {71, 4, 112, "da"}, /* scsi disk7 */ 935 {128, 4, 128, "da"}, /* scsi disk8 */ 936 {129, 4, 144, "da"}, /* scsi disk9 */ 937 {130, 4, 160, "da"}, /* scsi disk10 */ 938 {131, 4, 176, "da"}, /* scsi disk11 */ 939 {132, 4, 192, "da"}, /* scsi disk12 */ 940 {133, 4, 208, "da"}, /* scsi disk13 */ 941 {134, 4, 224, "da"}, /* scsi disk14 */ 942 {135, 4, 240, "da"}, /* scsi disk15 */ 943 944 {202, 4, 0, "xbd"}, /* xbd */ 945 946 {0, 0, 0, NULL}, 947 }; 948 int major = vdevice >> 8; 949 int minor = vdevice & 0xff; 950 int i; 951 952 if (vdevice & (1 << 28)) { 953 *unit = (vdevice & ((1 << 28) - 1)) >> 8; 954 *name = "xbd"; 955 return; 956 } 957 958 for (i = 0; info[i].major; i++) { 959 if (info[i].major == major) { 960 *unit = info[i].base + (minor >> info[i].shift); 961 *name = info[i].name; 962 return; 963 } 964 } 965 966 *unit = minor >> 4; 967 *name = "xbd"; 968 } 969 970 int 971 xbd_instance_create(struct xbd_softc *sc, blkif_sector_t sectors, 972 int vdevice, uint16_t vdisk_info, unsigned long sector_size) 973 { 974 char features[80]; 975 int unit, error = 0; 976 const char *name; 977 978 xbd_vdevice_to_unit(vdevice, &unit, &name); 979 980 sc->xbd_unit = unit; 981 982 if (strcmp(name, "xbd") != 0) 983 device_printf(sc->xbd_dev, "attaching as %s%d\n", name, unit); 984 985 if (xbd_feature_string(sc, features, sizeof(features)) > 0) { 986 device_printf(sc->xbd_dev, "features: %s\n", 987 features); 988 } 989 990 sc->xbd_disk = disk_alloc(); 991 sc->xbd_disk->d_unit = sc->xbd_unit; 992 sc->xbd_disk->d_open = xbd_open; 993 sc->xbd_disk->d_close = xbd_close; 994 sc->xbd_disk->d_ioctl = xbd_ioctl; 995 sc->xbd_disk->d_strategy = xbd_strategy; 996 sc->xbd_disk->d_dump = xbd_dump; 997 sc->xbd_disk->d_name = name; 998 sc->xbd_disk->d_drv1 = sc; 999 sc->xbd_disk->d_sectorsize = sector_size; 1000 1001 sc->xbd_disk->d_mediasize = sectors * sector_size; 1002 sc->xbd_disk->d_maxsize = sc->xbd_max_request_size; 1003 sc->xbd_disk->d_flags = 0; 1004 if ((sc->xbd_flags & (XBDF_FLUSH|XBDF_BARRIER)) != 0) { 1005 sc->xbd_disk->d_flags |= DISKFLAG_CANFLUSHCACHE; 1006 device_printf(sc->xbd_dev, 1007 "synchronize cache commands enabled.\n"); 1008 } 1009 disk_create(sc->xbd_disk, DISK_VERSION); 1010 1011 return error; 1012 } 1013 1014 static void 1015 xbd_free(struct xbd_softc *sc) 1016 { 1017 int i; 1018 1019 /* Prevent new requests being issued until we fix things up. */ 1020 mtx_lock(&sc->xbd_io_lock); 1021 sc->xbd_state = XBD_STATE_DISCONNECTED; 1022 mtx_unlock(&sc->xbd_io_lock); 1023 1024 /* Free resources associated with old device channel. */ 1025 xbd_free_ring(sc); 1026 if (sc->xbd_shadow) { 1027 1028 for (i = 0; i < sc->xbd_max_requests; i++) { 1029 struct xbd_command *cm; 1030 1031 cm = &sc->xbd_shadow[i]; 1032 if (cm->cm_sg_refs != NULL) { 1033 free(cm->cm_sg_refs, M_XENBLOCKFRONT); 1034 cm->cm_sg_refs = NULL; 1035 } 1036 1037 bus_dmamap_destroy(sc->xbd_io_dmat, cm->cm_map); 1038 } 1039 free(sc->xbd_shadow, M_XENBLOCKFRONT); 1040 sc->xbd_shadow = NULL; 1041 1042 bus_dma_tag_destroy(sc->xbd_io_dmat); 1043 1044 xbd_initq_cm(sc, XBD_Q_FREE); 1045 xbd_initq_cm(sc, XBD_Q_READY); 1046 xbd_initq_cm(sc, XBD_Q_COMPLETE); 1047 } 1048 1049 if (sc->xbd_irq) { 1050 unbind_from_irqhandler(sc->xbd_irq); 1051 sc->xbd_irq = 0; 1052 } 1053 } 1054 1055 /*--------------------------- State Change Handlers --------------------------*/ 1056 static void 1057 xbd_initialize(struct xbd_softc *sc) 1058 { 1059 const char *otherend_path; 1060 const char *node_path; 1061 uint32_t max_ring_page_order; 1062 int error; 1063 int i; 1064 1065 if (xenbus_get_state(sc->xbd_dev) != XenbusStateInitialising) { 1066 /* Initialization has already been performed. */ 1067 return; 1068 } 1069 1070 /* 1071 * Protocol defaults valid even if negotiation for a 1072 * setting fails. 1073 */ 1074 max_ring_page_order = 0; 1075 sc->xbd_ring_pages = 1; 1076 sc->xbd_max_request_segments = BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK; 1077 sc->xbd_max_request_size = 1078 XBD_SEGS_TO_SIZE(sc->xbd_max_request_segments); 1079 sc->xbd_max_request_blocks = 1080 BLKIF_SEGS_TO_BLOCKS(sc->xbd_max_request_segments); 1081 1082 /* 1083 * Protocol negotiation. 1084 * 1085 * \note xs_gather() returns on the first encountered error, so 1086 * we must use independant calls in order to guarantee 1087 * we don't miss information in a sparsly populated back-end 1088 * tree. 1089 * 1090 * \note xs_scanf() does not update variables for unmatched 1091 * fields. 1092 */ 1093 otherend_path = xenbus_get_otherend_path(sc->xbd_dev); 1094 node_path = xenbus_get_node(sc->xbd_dev); 1095 1096 /* Support both backend schemes for relaying ring page limits. */ 1097 (void)xs_scanf(XST_NIL, otherend_path, 1098 "max-ring-page-order", NULL, "%" PRIu32, 1099 &max_ring_page_order); 1100 sc->xbd_ring_pages = 1 << max_ring_page_order; 1101 (void)xs_scanf(XST_NIL, otherend_path, 1102 "max-ring-pages", NULL, "%" PRIu32, 1103 &sc->xbd_ring_pages); 1104 if (sc->xbd_ring_pages < 1) 1105 sc->xbd_ring_pages = 1; 1106 1107 sc->xbd_max_requests = 1108 BLKIF_MAX_RING_REQUESTS(sc->xbd_ring_pages * PAGE_SIZE); 1109 (void)xs_scanf(XST_NIL, otherend_path, 1110 "max-requests", NULL, "%" PRIu32, 1111 &sc->xbd_max_requests); 1112 1113 (void)xs_scanf(XST_NIL, otherend_path, 1114 "max-request-segments", NULL, "%" PRIu32, 1115 &sc->xbd_max_request_segments); 1116 1117 (void)xs_scanf(XST_NIL, otherend_path, 1118 "max-request-size", NULL, "%" PRIu32, 1119 &sc->xbd_max_request_size); 1120 1121 if (sc->xbd_ring_pages > XBD_MAX_RING_PAGES) { 1122 device_printf(sc->xbd_dev, 1123 "Back-end specified ring-pages of %u " 1124 "limited to front-end limit of %zu.\n", 1125 sc->xbd_ring_pages, XBD_MAX_RING_PAGES); 1126 sc->xbd_ring_pages = XBD_MAX_RING_PAGES; 1127 } 1128 1129 if (powerof2(sc->xbd_ring_pages) == 0) { 1130 uint32_t new_page_limit; 1131 1132 new_page_limit = 0x01 << (fls(sc->xbd_ring_pages) - 1); 1133 device_printf(sc->xbd_dev, 1134 "Back-end specified ring-pages of %u " 1135 "is not a power of 2. Limited to %u.\n", 1136 sc->xbd_ring_pages, new_page_limit); 1137 sc->xbd_ring_pages = new_page_limit; 1138 } 1139 1140 if (sc->xbd_max_requests > XBD_MAX_REQUESTS) { 1141 device_printf(sc->xbd_dev, 1142 "Back-end specified max_requests of %u " 1143 "limited to front-end limit of %u.\n", 1144 sc->xbd_max_requests, XBD_MAX_REQUESTS); 1145 sc->xbd_max_requests = XBD_MAX_REQUESTS; 1146 } 1147 1148 if (sc->xbd_max_request_segments > XBD_MAX_SEGMENTS_PER_REQUEST) { 1149 device_printf(sc->xbd_dev, 1150 "Back-end specified max_request_segments of %u " 1151 "limited to front-end limit of %u.\n", 1152 sc->xbd_max_request_segments, 1153 XBD_MAX_SEGMENTS_PER_REQUEST); 1154 sc->xbd_max_request_segments = XBD_MAX_SEGMENTS_PER_REQUEST; 1155 } 1156 1157 if (sc->xbd_max_request_size > XBD_MAX_REQUEST_SIZE) { 1158 device_printf(sc->xbd_dev, 1159 "Back-end specified max_request_size of %u " 1160 "limited to front-end limit of %u.\n", 1161 sc->xbd_max_request_size, 1162 XBD_MAX_REQUEST_SIZE); 1163 sc->xbd_max_request_size = XBD_MAX_REQUEST_SIZE; 1164 } 1165 1166 if (sc->xbd_max_request_size > 1167 XBD_SEGS_TO_SIZE(sc->xbd_max_request_segments)) { 1168 device_printf(sc->xbd_dev, 1169 "Back-end specified max_request_size of %u " 1170 "limited to front-end limit of %u. (Too few segments.)\n", 1171 sc->xbd_max_request_size, 1172 XBD_SEGS_TO_SIZE(sc->xbd_max_request_segments)); 1173 sc->xbd_max_request_size = 1174 XBD_SEGS_TO_SIZE(sc->xbd_max_request_segments); 1175 } 1176 1177 sc->xbd_max_request_blocks = 1178 BLKIF_SEGS_TO_BLOCKS(sc->xbd_max_request_segments); 1179 1180 /* Allocate datastructures based on negotiated values. */ 1181 error = bus_dma_tag_create( 1182 bus_get_dma_tag(sc->xbd_dev), /* parent */ 1183 512, PAGE_SIZE, /* algnmnt, boundary */ 1184 BUS_SPACE_MAXADDR, /* lowaddr */ 1185 BUS_SPACE_MAXADDR, /* highaddr */ 1186 NULL, NULL, /* filter, filterarg */ 1187 sc->xbd_max_request_size, 1188 sc->xbd_max_request_segments, 1189 PAGE_SIZE, /* maxsegsize */ 1190 BUS_DMA_ALLOCNOW, /* flags */ 1191 busdma_lock_mutex, /* lockfunc */ 1192 &sc->xbd_io_lock, /* lockarg */ 1193 &sc->xbd_io_dmat); 1194 if (error != 0) { 1195 xenbus_dev_fatal(sc->xbd_dev, error, 1196 "Cannot allocate parent DMA tag\n"); 1197 return; 1198 } 1199 1200 /* Per-transaction data allocation. */ 1201 sc->xbd_shadow = malloc(sizeof(*sc->xbd_shadow) * sc->xbd_max_requests, 1202 M_XENBLOCKFRONT, M_NOWAIT|M_ZERO); 1203 if (sc->xbd_shadow == NULL) { 1204 bus_dma_tag_destroy(sc->xbd_io_dmat); 1205 xenbus_dev_fatal(sc->xbd_dev, error, 1206 "Cannot allocate request structures\n"); 1207 return; 1208 } 1209 1210 for (i = 0; i < sc->xbd_max_requests; i++) { 1211 struct xbd_command *cm; 1212 1213 cm = &sc->xbd_shadow[i]; 1214 cm->cm_sg_refs = malloc( 1215 sizeof(grant_ref_t) * sc->xbd_max_request_segments, 1216 M_XENBLOCKFRONT, M_NOWAIT); 1217 if (cm->cm_sg_refs == NULL) 1218 break; 1219 cm->cm_id = i; 1220 cm->cm_flags = XBDCF_INITIALIZER; 1221 cm->cm_sc = sc; 1222 if (bus_dmamap_create(sc->xbd_io_dmat, 0, &cm->cm_map) != 0) 1223 break; 1224 xbd_free_command(cm); 1225 } 1226 1227 if (xbd_alloc_ring(sc) != 0) 1228 return; 1229 1230 /* Support both backend schemes for relaying ring page limits. */ 1231 if (sc->xbd_ring_pages > 1) { 1232 error = xs_printf(XST_NIL, node_path, 1233 "num-ring-pages","%u", 1234 sc->xbd_ring_pages); 1235 if (error) { 1236 xenbus_dev_fatal(sc->xbd_dev, error, 1237 "writing %s/num-ring-pages", 1238 node_path); 1239 return; 1240 } 1241 1242 error = xs_printf(XST_NIL, node_path, 1243 "ring-page-order", "%u", 1244 fls(sc->xbd_ring_pages) - 1); 1245 if (error) { 1246 xenbus_dev_fatal(sc->xbd_dev, error, 1247 "writing %s/ring-page-order", 1248 node_path); 1249 return; 1250 } 1251 } 1252 1253 error = xs_printf(XST_NIL, node_path, 1254 "max-requests","%u", 1255 sc->xbd_max_requests); 1256 if (error) { 1257 xenbus_dev_fatal(sc->xbd_dev, error, 1258 "writing %s/max-requests", 1259 node_path); 1260 return; 1261 } 1262 1263 error = xs_printf(XST_NIL, node_path, 1264 "max-request-segments","%u", 1265 sc->xbd_max_request_segments); 1266 if (error) { 1267 xenbus_dev_fatal(sc->xbd_dev, error, 1268 "writing %s/max-request-segments", 1269 node_path); 1270 return; 1271 } 1272 1273 error = xs_printf(XST_NIL, node_path, 1274 "max-request-size","%u", 1275 sc->xbd_max_request_size); 1276 if (error) { 1277 xenbus_dev_fatal(sc->xbd_dev, error, 1278 "writing %s/max-request-size", 1279 node_path); 1280 return; 1281 } 1282 1283 error = xs_printf(XST_NIL, node_path, "event-channel", 1284 "%u", irq_to_evtchn_port(sc->xbd_irq)); 1285 if (error) { 1286 xenbus_dev_fatal(sc->xbd_dev, error, 1287 "writing %s/event-channel", 1288 node_path); 1289 return; 1290 } 1291 1292 error = xs_printf(XST_NIL, node_path, "protocol", 1293 "%s", XEN_IO_PROTO_ABI_NATIVE); 1294 if (error) { 1295 xenbus_dev_fatal(sc->xbd_dev, error, 1296 "writing %s/protocol", 1297 node_path); 1298 return; 1299 } 1300 1301 xenbus_set_state(sc->xbd_dev, XenbusStateInitialised); 1302 } 1303 1304 /* 1305 * Invoked when the backend is finally 'ready' (and has published 1306 * the details about the physical device - #sectors, size, etc). 1307 */ 1308 static void 1309 xbd_connect(struct xbd_softc *sc) 1310 { 1311 device_t dev = sc->xbd_dev; 1312 unsigned long sectors, sector_size; 1313 unsigned int binfo; 1314 int err, feature_barrier, feature_flush; 1315 1316 if (sc->xbd_state == XBD_STATE_CONNECTED || 1317 sc->xbd_state == XBD_STATE_SUSPENDED) 1318 return; 1319 1320 DPRINTK("blkfront.c:connect:%s.\n", xenbus_get_otherend_path(dev)); 1321 1322 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev), 1323 "sectors", "%lu", §ors, 1324 "info", "%u", &binfo, 1325 "sector-size", "%lu", §or_size, 1326 NULL); 1327 if (err) { 1328 xenbus_dev_fatal(dev, err, 1329 "reading backend fields at %s", 1330 xenbus_get_otherend_path(dev)); 1331 return; 1332 } 1333 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev), 1334 "feature-barrier", "%lu", &feature_barrier, 1335 NULL); 1336 if (err == 0 && feature_barrier != 0) 1337 sc->xbd_flags |= XBDF_BARRIER; 1338 1339 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev), 1340 "feature-flush-cache", "%lu", &feature_flush, 1341 NULL); 1342 if (err == 0 && feature_flush != 0) 1343 sc->xbd_flags |= XBDF_FLUSH; 1344 1345 if (sc->xbd_disk == NULL) { 1346 device_printf(dev, "%juMB <%s> at %s", 1347 (uintmax_t) sectors / (1048576 / sector_size), 1348 device_get_desc(dev), 1349 xenbus_get_node(dev)); 1350 bus_print_child_footer(device_get_parent(dev), dev); 1351 1352 xbd_instance_create(sc, sectors, sc->xbd_vdevice, binfo, 1353 sector_size); 1354 } 1355 1356 (void)xenbus_set_state(dev, XenbusStateConnected); 1357 1358 /* Kick pending requests. */ 1359 mtx_lock(&sc->xbd_io_lock); 1360 sc->xbd_state = XBD_STATE_CONNECTED; 1361 xbd_startio(sc); 1362 sc->xbd_flags |= XBDF_READY; 1363 mtx_unlock(&sc->xbd_io_lock); 1364 } 1365 1366 /** 1367 * Handle the change of state of the backend to Closing. We must delete our 1368 * device-layer structures now, to ensure that writes are flushed through to 1369 * the backend. Once this is done, we can switch to Closed in 1370 * acknowledgement. 1371 */ 1372 static void 1373 xbd_closing(device_t dev) 1374 { 1375 struct xbd_softc *sc = device_get_softc(dev); 1376 1377 xenbus_set_state(dev, XenbusStateClosing); 1378 1379 DPRINTK("xbd_closing: %s removed\n", xenbus_get_node(dev)); 1380 1381 if (sc->xbd_disk != NULL) { 1382 disk_destroy(sc->xbd_disk); 1383 sc->xbd_disk = NULL; 1384 } 1385 1386 xenbus_set_state(dev, XenbusStateClosed); 1387 } 1388 1389 /*---------------------------- NewBus Entrypoints ----------------------------*/ 1390 static int 1391 xbd_probe(device_t dev) 1392 { 1393 1394 if (!strcmp(xenbus_get_type(dev), "vbd")) { 1395 device_set_desc(dev, "Virtual Block Device"); 1396 device_quiet(dev); 1397 return (0); 1398 } 1399 1400 return (ENXIO); 1401 } 1402 1403 /* 1404 * Setup supplies the backend dir, virtual device. We place an event 1405 * channel and shared frame entries. We watch backend to wait if it's 1406 * ok. 1407 */ 1408 static int 1409 xbd_attach(device_t dev) 1410 { 1411 struct xbd_softc *sc; 1412 const char *name; 1413 uint32_t vdevice; 1414 int error; 1415 int i; 1416 int unit; 1417 1418 /* FIXME: Use dynamic device id if this is not set. */ 1419 error = xs_scanf(XST_NIL, xenbus_get_node(dev), 1420 "virtual-device", NULL, "%" PRIu32, &vdevice); 1421 if (error) { 1422 xenbus_dev_fatal(dev, error, "reading virtual-device"); 1423 device_printf(dev, "Couldn't determine virtual device.\n"); 1424 return (error); 1425 } 1426 1427 xbd_vdevice_to_unit(vdevice, &unit, &name); 1428 if (!strcmp(name, "xbd")) 1429 device_set_unit(dev, unit); 1430 1431 sc = device_get_softc(dev); 1432 mtx_init(&sc->xbd_io_lock, "blkfront i/o lock", NULL, MTX_DEF); 1433 xbd_initqs(sc); 1434 for (i = 0; i < XBD_MAX_RING_PAGES; i++) 1435 sc->xbd_ring_ref[i] = GRANT_REF_INVALID; 1436 1437 sc->xbd_dev = dev; 1438 sc->xbd_vdevice = vdevice; 1439 sc->xbd_state = XBD_STATE_DISCONNECTED; 1440 1441 xbd_setup_sysctl(sc); 1442 1443 /* Wait for backend device to publish its protocol capabilities. */ 1444 xenbus_set_state(dev, XenbusStateInitialising); 1445 1446 return (0); 1447 } 1448 1449 static int 1450 xbd_detach(device_t dev) 1451 { 1452 struct xbd_softc *sc = device_get_softc(dev); 1453 1454 DPRINTK("%s: %s removed\n", __func__, xenbus_get_node(dev)); 1455 1456 xbd_free(sc); 1457 mtx_destroy(&sc->xbd_io_lock); 1458 1459 return 0; 1460 } 1461 1462 static int 1463 xbd_suspend(device_t dev) 1464 { 1465 struct xbd_softc *sc = device_get_softc(dev); 1466 int retval; 1467 int saved_state; 1468 1469 /* Prevent new requests being issued until we fix things up. */ 1470 mtx_lock(&sc->xbd_io_lock); 1471 saved_state = sc->xbd_state; 1472 sc->xbd_state = XBD_STATE_SUSPENDED; 1473 1474 /* Wait for outstanding I/O to drain. */ 1475 retval = 0; 1476 while (xbd_queue_length(sc, XBD_Q_BUSY) != 0) { 1477 if (msleep(&sc->xbd_cm_q[XBD_Q_BUSY], &sc->xbd_io_lock, 1478 PRIBIO, "blkf_susp", 30 * hz) == EWOULDBLOCK) { 1479 retval = EBUSY; 1480 break; 1481 } 1482 } 1483 mtx_unlock(&sc->xbd_io_lock); 1484 1485 if (retval != 0) 1486 sc->xbd_state = saved_state; 1487 1488 return (retval); 1489 } 1490 1491 static int 1492 xbd_resume(device_t dev) 1493 { 1494 struct xbd_softc *sc = device_get_softc(dev); 1495 1496 DPRINTK("xbd_resume: %s\n", xenbus_get_node(dev)); 1497 1498 xbd_free(sc); 1499 xbd_initialize(sc); 1500 return (0); 1501 } 1502 1503 /** 1504 * Callback received when the backend's state changes. 1505 */ 1506 static void 1507 xbd_backend_changed(device_t dev, XenbusState backend_state) 1508 { 1509 struct xbd_softc *sc = device_get_softc(dev); 1510 1511 DPRINTK("backend_state=%d\n", backend_state); 1512 1513 switch (backend_state) { 1514 case XenbusStateUnknown: 1515 case XenbusStateInitialising: 1516 case XenbusStateReconfigured: 1517 case XenbusStateReconfiguring: 1518 case XenbusStateClosed: 1519 break; 1520 1521 case XenbusStateInitWait: 1522 case XenbusStateInitialised: 1523 xbd_initialize(sc); 1524 break; 1525 1526 case XenbusStateConnected: 1527 xbd_initialize(sc); 1528 xbd_connect(sc); 1529 break; 1530 1531 case XenbusStateClosing: 1532 if (sc->xbd_users > 0) 1533 xenbus_dev_error(dev, -EBUSY, 1534 "Device in use; refusing to close"); 1535 else 1536 xbd_closing(dev); 1537 break; 1538 } 1539 } 1540 1541 /*---------------------------- NewBus Registration ---------------------------*/ 1542 static device_method_t xbd_methods[] = { 1543 /* Device interface */ 1544 DEVMETHOD(device_probe, xbd_probe), 1545 DEVMETHOD(device_attach, xbd_attach), 1546 DEVMETHOD(device_detach, xbd_detach), 1547 DEVMETHOD(device_shutdown, bus_generic_shutdown), 1548 DEVMETHOD(device_suspend, xbd_suspend), 1549 DEVMETHOD(device_resume, xbd_resume), 1550 1551 /* Xenbus interface */ 1552 DEVMETHOD(xenbus_otherend_changed, xbd_backend_changed), 1553 1554 { 0, 0 } 1555 }; 1556 1557 static driver_t xbd_driver = { 1558 "xbd", 1559 xbd_methods, 1560 sizeof(struct xbd_softc), 1561 }; 1562 devclass_t xbd_devclass; 1563 1564 DRIVER_MODULE(xbd, xenbusb_front, xbd_driver, xbd_devclass, 0, 0); 1565