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 printf("error %d in xbd_queue_cb\n", error); 178 cm->cm_bp->bio_error = EIO; 179 biodone(cm->cm_bp); 180 xbd_free_command(cm); 181 return; 182 } 183 184 /* Fill out a communications ring structure. */ 185 ring_req = RING_GET_REQUEST(&sc->xbd_ring, sc->xbd_ring.req_prod_pvt); 186 sc->xbd_ring.req_prod_pvt++; 187 ring_req->id = cm->cm_id; 188 ring_req->operation = cm->cm_operation; 189 ring_req->sector_number = cm->cm_sector_number; 190 ring_req->handle = (blkif_vdev_t)(uintptr_t)sc->xbd_disk; 191 ring_req->nr_segments = nsegs; 192 cm->cm_nseg = nsegs; 193 194 block_segs = MIN(nsegs, BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK); 195 sg = ring_req->seg; 196 last_block_sg = sg + block_segs; 197 sg_ref = cm->cm_sg_refs; 198 199 while (1) { 200 201 while (sg < last_block_sg) { 202 buffer_ma = segs->ds_addr; 203 fsect = (buffer_ma & PAGE_MASK) >> XBD_SECTOR_SHFT; 204 lsect = fsect + (segs->ds_len >> XBD_SECTOR_SHFT) - 1; 205 206 KASSERT(lsect <= 7, ("XEN disk driver data cannot " 207 "cross a page boundary")); 208 209 /* install a grant reference. */ 210 ref = gnttab_claim_grant_reference(&cm->cm_gref_head); 211 212 /* 213 * GNTTAB_LIST_END == 0xffffffff, but it is private 214 * to gnttab.c. 215 */ 216 KASSERT(ref != ~0, ("grant_reference failed")); 217 218 gnttab_grant_foreign_access_ref( 219 ref, 220 xenbus_get_otherend_id(sc->xbd_dev), 221 buffer_ma >> PAGE_SHIFT, 222 ring_req->operation == BLKIF_OP_WRITE); 223 224 *sg_ref = ref; 225 *sg = (struct blkif_request_segment) { 226 .gref = ref, 227 .first_sect = fsect, 228 .last_sect = lsect 229 }; 230 sg++; 231 sg_ref++; 232 segs++; 233 nsegs--; 234 } 235 block_segs = MIN(nsegs, BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK); 236 if (block_segs == 0) 237 break; 238 239 sg = BLKRING_GET_SEG_BLOCK(&sc->xbd_ring, 240 sc->xbd_ring.req_prod_pvt); 241 sc->xbd_ring.req_prod_pvt++; 242 last_block_sg = sg + block_segs; 243 } 244 245 if (cm->cm_operation == BLKIF_OP_READ) 246 op = BUS_DMASYNC_PREREAD; 247 else if (cm->cm_operation == BLKIF_OP_WRITE) 248 op = BUS_DMASYNC_PREWRITE; 249 else 250 op = 0; 251 bus_dmamap_sync(sc->xbd_io_dmat, cm->cm_map, op); 252 253 gnttab_free_grant_references(cm->cm_gref_head); 254 255 xbd_enqueue_cm(cm, XBD_Q_BUSY); 256 257 /* 258 * If bus dma had to asynchronously call us back to dispatch 259 * this command, we are no longer executing in the context of 260 * xbd_startio(). Thus we cannot rely on xbd_startio()'s call to 261 * xbd_flush_requests() to publish this command to the backend 262 * along with any other commands that it could batch. 263 */ 264 if ((cm->cm_flags & XBDCF_ASYNC_MAPPING) != 0) 265 xbd_flush_requests(sc); 266 267 return; 268 } 269 270 static int 271 xbd_queue_request(struct xbd_softc *sc, struct xbd_command *cm) 272 { 273 int error; 274 275 if (cm->cm_bp != NULL) 276 error = bus_dmamap_load_bio(sc->xbd_io_dmat, cm->cm_map, 277 cm->cm_bp, xbd_queue_cb, cm, 0); 278 else 279 error = bus_dmamap_load(sc->xbd_io_dmat, cm->cm_map, 280 cm->cm_data, cm->cm_datalen, xbd_queue_cb, cm, 0); 281 if (error == EINPROGRESS) { 282 /* 283 * Maintain queuing order by freezing the queue. The next 284 * command may not require as many resources as the command 285 * we just attempted to map, so we can't rely on bus dma 286 * blocking for it too. 287 */ 288 xbd_cm_freeze(sc, cm, XBDCF_ASYNC_MAPPING); 289 return (0); 290 } 291 292 return (error); 293 } 294 295 static void 296 xbd_restart_queue_callback(void *arg) 297 { 298 struct xbd_softc *sc = arg; 299 300 mtx_lock(&sc->xbd_io_lock); 301 302 xbd_thaw(sc, XBDF_GNT_SHORTAGE); 303 304 xbd_startio(sc); 305 306 mtx_unlock(&sc->xbd_io_lock); 307 } 308 309 static struct xbd_command * 310 xbd_bio_command(struct xbd_softc *sc) 311 { 312 struct xbd_command *cm; 313 struct bio *bp; 314 315 if (__predict_false(sc->xbd_state != XBD_STATE_CONNECTED)) 316 return (NULL); 317 318 bp = xbd_dequeue_bio(sc); 319 if (bp == NULL) 320 return (NULL); 321 322 if ((cm = xbd_dequeue_cm(sc, XBD_Q_FREE)) == NULL) { 323 xbd_freeze(sc, XBDF_CM_SHORTAGE); 324 xbd_requeue_bio(sc, bp); 325 return (NULL); 326 } 327 328 if (gnttab_alloc_grant_references(sc->xbd_max_request_segments, 329 &cm->cm_gref_head) != 0) { 330 gnttab_request_free_callback(&sc->xbd_callback, 331 xbd_restart_queue_callback, sc, 332 sc->xbd_max_request_segments); 333 xbd_freeze(sc, XBDF_GNT_SHORTAGE); 334 xbd_requeue_bio(sc, bp); 335 xbd_enqueue_cm(cm, XBD_Q_FREE); 336 return (NULL); 337 } 338 339 cm->cm_bp = bp; 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 (__predict_false(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 (__predict_false(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 (__predict_false(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 = xen_intr_alloc_and_bind_local_port(sc->xbd_dev, 786 xenbus_get_otherend_id(sc->xbd_dev), NULL, xbd_int, sc, 787 INTR_TYPE_BIO | INTR_MPSAFE, &sc->xen_intr_handle); 788 if (error) { 789 xenbus_dev_fatal(sc->xbd_dev, error, 790 "xen_intr_alloc_and_bind_local_port failed"); 791 return (error); 792 } 793 794 return (0); 795 } 796 797 static void 798 xbd_free_ring(struct xbd_softc *sc) 799 { 800 int i; 801 802 if (sc->xbd_ring.sring == NULL) 803 return; 804 805 for (i = 0; i < sc->xbd_ring_pages; i++) { 806 if (sc->xbd_ring_ref[i] != GRANT_REF_INVALID) { 807 gnttab_end_foreign_access_ref(sc->xbd_ring_ref[i]); 808 sc->xbd_ring_ref[i] = GRANT_REF_INVALID; 809 } 810 } 811 free(sc->xbd_ring.sring, M_XENBLOCKFRONT); 812 sc->xbd_ring.sring = NULL; 813 } 814 815 /*-------------------------- Initialization/Teardown -------------------------*/ 816 static int 817 xbd_feature_string(struct xbd_softc *sc, char *features, size_t len) 818 { 819 struct sbuf sb; 820 int feature_cnt; 821 822 sbuf_new(&sb, features, len, SBUF_FIXEDLEN); 823 824 feature_cnt = 0; 825 if ((sc->xbd_flags & XBDF_FLUSH) != 0) { 826 sbuf_printf(&sb, "flush"); 827 feature_cnt++; 828 } 829 830 if ((sc->xbd_flags & XBDF_BARRIER) != 0) { 831 if (feature_cnt != 0) 832 sbuf_printf(&sb, ", "); 833 sbuf_printf(&sb, "write_barrier"); 834 feature_cnt++; 835 } 836 837 (void) sbuf_finish(&sb); 838 return (sbuf_len(&sb)); 839 } 840 841 static int 842 xbd_sysctl_features(SYSCTL_HANDLER_ARGS) 843 { 844 char features[80]; 845 struct xbd_softc *sc = arg1; 846 int error; 847 int len; 848 849 error = sysctl_wire_old_buffer(req, 0); 850 if (error != 0) 851 return (error); 852 853 len = xbd_feature_string(sc, features, sizeof(features)); 854 855 /* len is -1 on error, which will make the SYSCTL_OUT a no-op. */ 856 return (SYSCTL_OUT(req, features, len + 1/*NUL*/)); 857 } 858 859 static void 860 xbd_setup_sysctl(struct xbd_softc *xbd) 861 { 862 struct sysctl_ctx_list *sysctl_ctx = NULL; 863 struct sysctl_oid *sysctl_tree = NULL; 864 struct sysctl_oid_list *children; 865 866 sysctl_ctx = device_get_sysctl_ctx(xbd->xbd_dev); 867 if (sysctl_ctx == NULL) 868 return; 869 870 sysctl_tree = device_get_sysctl_tree(xbd->xbd_dev); 871 if (sysctl_tree == NULL) 872 return; 873 874 children = SYSCTL_CHILDREN(sysctl_tree); 875 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 876 "max_requests", CTLFLAG_RD, &xbd->xbd_max_requests, -1, 877 "maximum outstanding requests (negotiated)"); 878 879 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 880 "max_request_segments", CTLFLAG_RD, 881 &xbd->xbd_max_request_segments, 0, 882 "maximum number of pages per requests (negotiated)"); 883 884 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 885 "max_request_size", CTLFLAG_RD, &xbd->xbd_max_request_size, 0, 886 "maximum size in bytes of a request (negotiated)"); 887 888 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 889 "ring_pages", CTLFLAG_RD, &xbd->xbd_ring_pages, 0, 890 "communication channel pages (negotiated)"); 891 892 SYSCTL_ADD_PROC(sysctl_ctx, children, OID_AUTO, 893 "features", CTLTYPE_STRING|CTLFLAG_RD, xbd, 0, 894 xbd_sysctl_features, "A", "protocol features (negotiated)"); 895 } 896 897 /* 898 * Translate Linux major/minor to an appropriate name and unit 899 * number. For HVM guests, this allows us to use the same drive names 900 * with blkfront as the emulated drives, easing transition slightly. 901 */ 902 static void 903 xbd_vdevice_to_unit(uint32_t vdevice, int *unit, const char **name) 904 { 905 static struct vdev_info { 906 int major; 907 int shift; 908 int base; 909 const char *name; 910 } info[] = { 911 {3, 6, 0, "ada"}, /* ide0 */ 912 {22, 6, 2, "ada"}, /* ide1 */ 913 {33, 6, 4, "ada"}, /* ide2 */ 914 {34, 6, 6, "ada"}, /* ide3 */ 915 {56, 6, 8, "ada"}, /* ide4 */ 916 {57, 6, 10, "ada"}, /* ide5 */ 917 {88, 6, 12, "ada"}, /* ide6 */ 918 {89, 6, 14, "ada"}, /* ide7 */ 919 {90, 6, 16, "ada"}, /* ide8 */ 920 {91, 6, 18, "ada"}, /* ide9 */ 921 922 {8, 4, 0, "da"}, /* scsi disk0 */ 923 {65, 4, 16, "da"}, /* scsi disk1 */ 924 {66, 4, 32, "da"}, /* scsi disk2 */ 925 {67, 4, 48, "da"}, /* scsi disk3 */ 926 {68, 4, 64, "da"}, /* scsi disk4 */ 927 {69, 4, 80, "da"}, /* scsi disk5 */ 928 {70, 4, 96, "da"}, /* scsi disk6 */ 929 {71, 4, 112, "da"}, /* scsi disk7 */ 930 {128, 4, 128, "da"}, /* scsi disk8 */ 931 {129, 4, 144, "da"}, /* scsi disk9 */ 932 {130, 4, 160, "da"}, /* scsi disk10 */ 933 {131, 4, 176, "da"}, /* scsi disk11 */ 934 {132, 4, 192, "da"}, /* scsi disk12 */ 935 {133, 4, 208, "da"}, /* scsi disk13 */ 936 {134, 4, 224, "da"}, /* scsi disk14 */ 937 {135, 4, 240, "da"}, /* scsi disk15 */ 938 939 {202, 4, 0, "xbd"}, /* xbd */ 940 941 {0, 0, 0, NULL}, 942 }; 943 int major = vdevice >> 8; 944 int minor = vdevice & 0xff; 945 int i; 946 947 if (vdevice & (1 << 28)) { 948 *unit = (vdevice & ((1 << 28) - 1)) >> 8; 949 *name = "xbd"; 950 return; 951 } 952 953 for (i = 0; info[i].major; i++) { 954 if (info[i].major == major) { 955 *unit = info[i].base + (minor >> info[i].shift); 956 *name = info[i].name; 957 return; 958 } 959 } 960 961 *unit = minor >> 4; 962 *name = "xbd"; 963 } 964 965 int 966 xbd_instance_create(struct xbd_softc *sc, blkif_sector_t sectors, 967 int vdevice, uint16_t vdisk_info, unsigned long sector_size) 968 { 969 char features[80]; 970 int unit, error = 0; 971 const char *name; 972 973 xbd_vdevice_to_unit(vdevice, &unit, &name); 974 975 sc->xbd_unit = unit; 976 977 if (strcmp(name, "xbd") != 0) 978 device_printf(sc->xbd_dev, "attaching as %s%d\n", name, unit); 979 980 if (xbd_feature_string(sc, features, sizeof(features)) > 0) { 981 device_printf(sc->xbd_dev, "features: %s\n", 982 features); 983 } 984 985 sc->xbd_disk = disk_alloc(); 986 sc->xbd_disk->d_unit = sc->xbd_unit; 987 sc->xbd_disk->d_open = xbd_open; 988 sc->xbd_disk->d_close = xbd_close; 989 sc->xbd_disk->d_ioctl = xbd_ioctl; 990 sc->xbd_disk->d_strategy = xbd_strategy; 991 sc->xbd_disk->d_dump = xbd_dump; 992 sc->xbd_disk->d_name = name; 993 sc->xbd_disk->d_drv1 = sc; 994 sc->xbd_disk->d_sectorsize = sector_size; 995 996 sc->xbd_disk->d_mediasize = sectors * sector_size; 997 sc->xbd_disk->d_maxsize = sc->xbd_max_request_size; 998 sc->xbd_disk->d_flags = DISKFLAG_UNMAPPED_BIO; 999 if ((sc->xbd_flags & (XBDF_FLUSH|XBDF_BARRIER)) != 0) { 1000 sc->xbd_disk->d_flags |= DISKFLAG_CANFLUSHCACHE; 1001 device_printf(sc->xbd_dev, 1002 "synchronize cache commands enabled.\n"); 1003 } 1004 disk_create(sc->xbd_disk, DISK_VERSION); 1005 1006 return error; 1007 } 1008 1009 static void 1010 xbd_free(struct xbd_softc *sc) 1011 { 1012 int i; 1013 1014 /* Prevent new requests being issued until we fix things up. */ 1015 mtx_lock(&sc->xbd_io_lock); 1016 sc->xbd_state = XBD_STATE_DISCONNECTED; 1017 mtx_unlock(&sc->xbd_io_lock); 1018 1019 /* Free resources associated with old device channel. */ 1020 xbd_free_ring(sc); 1021 if (sc->xbd_shadow) { 1022 1023 for (i = 0; i < sc->xbd_max_requests; i++) { 1024 struct xbd_command *cm; 1025 1026 cm = &sc->xbd_shadow[i]; 1027 if (cm->cm_sg_refs != NULL) { 1028 free(cm->cm_sg_refs, M_XENBLOCKFRONT); 1029 cm->cm_sg_refs = NULL; 1030 } 1031 1032 bus_dmamap_destroy(sc->xbd_io_dmat, cm->cm_map); 1033 } 1034 free(sc->xbd_shadow, M_XENBLOCKFRONT); 1035 sc->xbd_shadow = NULL; 1036 1037 bus_dma_tag_destroy(sc->xbd_io_dmat); 1038 1039 xbd_initq_cm(sc, XBD_Q_FREE); 1040 xbd_initq_cm(sc, XBD_Q_READY); 1041 xbd_initq_cm(sc, XBD_Q_COMPLETE); 1042 } 1043 1044 xen_intr_unbind(&sc->xen_intr_handle); 1045 1046 } 1047 1048 /*--------------------------- State Change Handlers --------------------------*/ 1049 static void 1050 xbd_initialize(struct xbd_softc *sc) 1051 { 1052 const char *otherend_path; 1053 const char *node_path; 1054 uint32_t max_ring_page_order; 1055 int error; 1056 int i; 1057 1058 if (xenbus_get_state(sc->xbd_dev) != XenbusStateInitialising) { 1059 /* Initialization has already been performed. */ 1060 return; 1061 } 1062 1063 /* 1064 * Protocol defaults valid even if negotiation for a 1065 * setting fails. 1066 */ 1067 max_ring_page_order = 0; 1068 sc->xbd_ring_pages = 1; 1069 sc->xbd_max_request_segments = BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK; 1070 sc->xbd_max_request_size = 1071 XBD_SEGS_TO_SIZE(sc->xbd_max_request_segments); 1072 sc->xbd_max_request_blocks = 1073 BLKIF_SEGS_TO_BLOCKS(sc->xbd_max_request_segments); 1074 1075 /* 1076 * Protocol negotiation. 1077 * 1078 * \note xs_gather() returns on the first encountered error, so 1079 * we must use independant calls in order to guarantee 1080 * we don't miss information in a sparsly populated back-end 1081 * tree. 1082 * 1083 * \note xs_scanf() does not update variables for unmatched 1084 * fields. 1085 */ 1086 otherend_path = xenbus_get_otherend_path(sc->xbd_dev); 1087 node_path = xenbus_get_node(sc->xbd_dev); 1088 1089 /* Support both backend schemes for relaying ring page limits. */ 1090 (void)xs_scanf(XST_NIL, otherend_path, 1091 "max-ring-page-order", NULL, "%" PRIu32, 1092 &max_ring_page_order); 1093 sc->xbd_ring_pages = 1 << max_ring_page_order; 1094 (void)xs_scanf(XST_NIL, otherend_path, 1095 "max-ring-pages", NULL, "%" PRIu32, 1096 &sc->xbd_ring_pages); 1097 if (sc->xbd_ring_pages < 1) 1098 sc->xbd_ring_pages = 1; 1099 1100 sc->xbd_max_requests = 1101 BLKIF_MAX_RING_REQUESTS(sc->xbd_ring_pages * PAGE_SIZE); 1102 (void)xs_scanf(XST_NIL, otherend_path, 1103 "max-requests", NULL, "%" PRIu32, 1104 &sc->xbd_max_requests); 1105 1106 (void)xs_scanf(XST_NIL, otherend_path, 1107 "max-request-segments", NULL, "%" PRIu32, 1108 &sc->xbd_max_request_segments); 1109 1110 (void)xs_scanf(XST_NIL, otherend_path, 1111 "max-request-size", NULL, "%" PRIu32, 1112 &sc->xbd_max_request_size); 1113 1114 if (sc->xbd_ring_pages > XBD_MAX_RING_PAGES) { 1115 device_printf(sc->xbd_dev, 1116 "Back-end specified ring-pages of %u " 1117 "limited to front-end limit of %zu.\n", 1118 sc->xbd_ring_pages, XBD_MAX_RING_PAGES); 1119 sc->xbd_ring_pages = XBD_MAX_RING_PAGES; 1120 } 1121 1122 if (powerof2(sc->xbd_ring_pages) == 0) { 1123 uint32_t new_page_limit; 1124 1125 new_page_limit = 0x01 << (fls(sc->xbd_ring_pages) - 1); 1126 device_printf(sc->xbd_dev, 1127 "Back-end specified ring-pages of %u " 1128 "is not a power of 2. Limited to %u.\n", 1129 sc->xbd_ring_pages, new_page_limit); 1130 sc->xbd_ring_pages = new_page_limit; 1131 } 1132 1133 if (sc->xbd_max_requests > XBD_MAX_REQUESTS) { 1134 device_printf(sc->xbd_dev, 1135 "Back-end specified max_requests of %u " 1136 "limited to front-end limit of %u.\n", 1137 sc->xbd_max_requests, XBD_MAX_REQUESTS); 1138 sc->xbd_max_requests = XBD_MAX_REQUESTS; 1139 } 1140 1141 if (sc->xbd_max_request_segments > XBD_MAX_SEGMENTS_PER_REQUEST) { 1142 device_printf(sc->xbd_dev, 1143 "Back-end specified max_request_segments of %u " 1144 "limited to front-end limit of %u.\n", 1145 sc->xbd_max_request_segments, 1146 XBD_MAX_SEGMENTS_PER_REQUEST); 1147 sc->xbd_max_request_segments = XBD_MAX_SEGMENTS_PER_REQUEST; 1148 } 1149 1150 if (sc->xbd_max_request_size > XBD_MAX_REQUEST_SIZE) { 1151 device_printf(sc->xbd_dev, 1152 "Back-end specified max_request_size of %u " 1153 "limited to front-end limit of %u.\n", 1154 sc->xbd_max_request_size, 1155 XBD_MAX_REQUEST_SIZE); 1156 sc->xbd_max_request_size = XBD_MAX_REQUEST_SIZE; 1157 } 1158 1159 if (sc->xbd_max_request_size > 1160 XBD_SEGS_TO_SIZE(sc->xbd_max_request_segments)) { 1161 device_printf(sc->xbd_dev, 1162 "Back-end specified max_request_size of %u " 1163 "limited to front-end limit of %u. (Too few segments.)\n", 1164 sc->xbd_max_request_size, 1165 XBD_SEGS_TO_SIZE(sc->xbd_max_request_segments)); 1166 sc->xbd_max_request_size = 1167 XBD_SEGS_TO_SIZE(sc->xbd_max_request_segments); 1168 } 1169 1170 sc->xbd_max_request_blocks = 1171 BLKIF_SEGS_TO_BLOCKS(sc->xbd_max_request_segments); 1172 1173 /* Allocate datastructures based on negotiated values. */ 1174 error = bus_dma_tag_create( 1175 bus_get_dma_tag(sc->xbd_dev), /* parent */ 1176 512, PAGE_SIZE, /* algnmnt, boundary */ 1177 BUS_SPACE_MAXADDR, /* lowaddr */ 1178 BUS_SPACE_MAXADDR, /* highaddr */ 1179 NULL, NULL, /* filter, filterarg */ 1180 sc->xbd_max_request_size, 1181 sc->xbd_max_request_segments, 1182 PAGE_SIZE, /* maxsegsize */ 1183 BUS_DMA_ALLOCNOW, /* flags */ 1184 busdma_lock_mutex, /* lockfunc */ 1185 &sc->xbd_io_lock, /* lockarg */ 1186 &sc->xbd_io_dmat); 1187 if (error != 0) { 1188 xenbus_dev_fatal(sc->xbd_dev, error, 1189 "Cannot allocate parent DMA tag\n"); 1190 return; 1191 } 1192 1193 /* Per-transaction data allocation. */ 1194 sc->xbd_shadow = malloc(sizeof(*sc->xbd_shadow) * sc->xbd_max_requests, 1195 M_XENBLOCKFRONT, M_NOWAIT|M_ZERO); 1196 if (sc->xbd_shadow == NULL) { 1197 bus_dma_tag_destroy(sc->xbd_io_dmat); 1198 xenbus_dev_fatal(sc->xbd_dev, error, 1199 "Cannot allocate request structures\n"); 1200 return; 1201 } 1202 1203 for (i = 0; i < sc->xbd_max_requests; i++) { 1204 struct xbd_command *cm; 1205 1206 cm = &sc->xbd_shadow[i]; 1207 cm->cm_sg_refs = malloc( 1208 sizeof(grant_ref_t) * sc->xbd_max_request_segments, 1209 M_XENBLOCKFRONT, M_NOWAIT); 1210 if (cm->cm_sg_refs == NULL) 1211 break; 1212 cm->cm_id = i; 1213 cm->cm_flags = XBDCF_INITIALIZER; 1214 cm->cm_sc = sc; 1215 if (bus_dmamap_create(sc->xbd_io_dmat, 0, &cm->cm_map) != 0) 1216 break; 1217 xbd_free_command(cm); 1218 } 1219 1220 if (xbd_alloc_ring(sc) != 0) 1221 return; 1222 1223 /* Support both backend schemes for relaying ring page limits. */ 1224 if (sc->xbd_ring_pages > 1) { 1225 error = xs_printf(XST_NIL, node_path, 1226 "num-ring-pages","%u", 1227 sc->xbd_ring_pages); 1228 if (error) { 1229 xenbus_dev_fatal(sc->xbd_dev, error, 1230 "writing %s/num-ring-pages", 1231 node_path); 1232 return; 1233 } 1234 1235 error = xs_printf(XST_NIL, node_path, 1236 "ring-page-order", "%u", 1237 fls(sc->xbd_ring_pages) - 1); 1238 if (error) { 1239 xenbus_dev_fatal(sc->xbd_dev, error, 1240 "writing %s/ring-page-order", 1241 node_path); 1242 return; 1243 } 1244 } 1245 1246 error = xs_printf(XST_NIL, node_path, 1247 "max-requests","%u", 1248 sc->xbd_max_requests); 1249 if (error) { 1250 xenbus_dev_fatal(sc->xbd_dev, error, 1251 "writing %s/max-requests", 1252 node_path); 1253 return; 1254 } 1255 1256 error = xs_printf(XST_NIL, node_path, 1257 "max-request-segments","%u", 1258 sc->xbd_max_request_segments); 1259 if (error) { 1260 xenbus_dev_fatal(sc->xbd_dev, error, 1261 "writing %s/max-request-segments", 1262 node_path); 1263 return; 1264 } 1265 1266 error = xs_printf(XST_NIL, node_path, 1267 "max-request-size","%u", 1268 sc->xbd_max_request_size); 1269 if (error) { 1270 xenbus_dev_fatal(sc->xbd_dev, error, 1271 "writing %s/max-request-size", 1272 node_path); 1273 return; 1274 } 1275 1276 error = xs_printf(XST_NIL, node_path, "event-channel", 1277 "%u", xen_intr_port(sc->xen_intr_handle)); 1278 if (error) { 1279 xenbus_dev_fatal(sc->xbd_dev, error, 1280 "writing %s/event-channel", 1281 node_path); 1282 return; 1283 } 1284 1285 error = xs_printf(XST_NIL, node_path, "protocol", 1286 "%s", XEN_IO_PROTO_ABI_NATIVE); 1287 if (error) { 1288 xenbus_dev_fatal(sc->xbd_dev, error, 1289 "writing %s/protocol", 1290 node_path); 1291 return; 1292 } 1293 1294 xenbus_set_state(sc->xbd_dev, XenbusStateInitialised); 1295 } 1296 1297 /* 1298 * Invoked when the backend is finally 'ready' (and has published 1299 * the details about the physical device - #sectors, size, etc). 1300 */ 1301 static void 1302 xbd_connect(struct xbd_softc *sc) 1303 { 1304 device_t dev = sc->xbd_dev; 1305 unsigned long sectors, sector_size; 1306 unsigned int binfo; 1307 int err, feature_barrier, feature_flush; 1308 1309 if (sc->xbd_state == XBD_STATE_CONNECTED || 1310 sc->xbd_state == XBD_STATE_SUSPENDED) 1311 return; 1312 1313 DPRINTK("blkfront.c:connect:%s.\n", xenbus_get_otherend_path(dev)); 1314 1315 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev), 1316 "sectors", "%lu", §ors, 1317 "info", "%u", &binfo, 1318 "sector-size", "%lu", §or_size, 1319 NULL); 1320 if (err) { 1321 xenbus_dev_fatal(dev, err, 1322 "reading backend fields at %s", 1323 xenbus_get_otherend_path(dev)); 1324 return; 1325 } 1326 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev), 1327 "feature-barrier", "%lu", &feature_barrier, 1328 NULL); 1329 if (err == 0 && feature_barrier != 0) 1330 sc->xbd_flags |= XBDF_BARRIER; 1331 1332 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev), 1333 "feature-flush-cache", "%lu", &feature_flush, 1334 NULL); 1335 if (err == 0 && feature_flush != 0) 1336 sc->xbd_flags |= XBDF_FLUSH; 1337 1338 if (sc->xbd_disk == NULL) { 1339 device_printf(dev, "%juMB <%s> at %s", 1340 (uintmax_t) sectors / (1048576 / sector_size), 1341 device_get_desc(dev), 1342 xenbus_get_node(dev)); 1343 bus_print_child_footer(device_get_parent(dev), dev); 1344 1345 xbd_instance_create(sc, sectors, sc->xbd_vdevice, binfo, 1346 sector_size); 1347 } 1348 1349 (void)xenbus_set_state(dev, XenbusStateConnected); 1350 1351 /* Kick pending requests. */ 1352 mtx_lock(&sc->xbd_io_lock); 1353 sc->xbd_state = XBD_STATE_CONNECTED; 1354 xbd_startio(sc); 1355 sc->xbd_flags |= XBDF_READY; 1356 mtx_unlock(&sc->xbd_io_lock); 1357 } 1358 1359 /** 1360 * Handle the change of state of the backend to Closing. We must delete our 1361 * device-layer structures now, to ensure that writes are flushed through to 1362 * the backend. Once this is done, we can switch to Closed in 1363 * acknowledgement. 1364 */ 1365 static void 1366 xbd_closing(device_t dev) 1367 { 1368 struct xbd_softc *sc = device_get_softc(dev); 1369 1370 xenbus_set_state(dev, XenbusStateClosing); 1371 1372 DPRINTK("xbd_closing: %s removed\n", xenbus_get_node(dev)); 1373 1374 if (sc->xbd_disk != NULL) { 1375 disk_destroy(sc->xbd_disk); 1376 sc->xbd_disk = NULL; 1377 } 1378 1379 xenbus_set_state(dev, XenbusStateClosed); 1380 } 1381 1382 /*---------------------------- NewBus Entrypoints ----------------------------*/ 1383 static int 1384 xbd_probe(device_t dev) 1385 { 1386 if (strcmp(xenbus_get_type(dev), "vbd") != 0) 1387 return (ENXIO); 1388 1389 if (xen_hvm_domain()) { 1390 int error; 1391 char *type; 1392 1393 /* 1394 * When running in an HVM domain, IDE disk emulation is 1395 * disabled early in boot so that native drivers will 1396 * not see emulated hardware. However, CDROM device 1397 * emulation cannot be disabled. 1398 * 1399 * Through use of FreeBSD's vm_guest and xen_hvm_domain() 1400 * APIs, we could modify the native CDROM driver to fail its 1401 * probe when running under Xen. Unfortunatlely, the PV 1402 * CDROM support in XenServer (up through at least version 1403 * 6.2) isn't functional, so we instead rely on the emulated 1404 * CDROM instance, and fail to attach the PV one here in 1405 * the blkfront driver. 1406 */ 1407 error = xs_read(XST_NIL, xenbus_get_node(dev), 1408 "device-type", NULL, (void **) &type); 1409 if (error) 1410 return (ENXIO); 1411 1412 if (strncmp(type, "cdrom", 5) == 0) { 1413 free(type, M_XENSTORE); 1414 return (ENXIO); 1415 } 1416 free(type, M_XENSTORE); 1417 } 1418 1419 device_set_desc(dev, "Virtual Block Device"); 1420 device_quiet(dev); 1421 return (0); 1422 } 1423 1424 /* 1425 * Setup supplies the backend dir, virtual device. We place an event 1426 * channel and shared frame entries. We watch backend to wait if it's 1427 * ok. 1428 */ 1429 static int 1430 xbd_attach(device_t dev) 1431 { 1432 struct xbd_softc *sc; 1433 const char *name; 1434 uint32_t vdevice; 1435 int error; 1436 int i; 1437 int unit; 1438 1439 /* FIXME: Use dynamic device id if this is not set. */ 1440 error = xs_scanf(XST_NIL, xenbus_get_node(dev), 1441 "virtual-device", NULL, "%" PRIu32, &vdevice); 1442 if (error) 1443 error = xs_scanf(XST_NIL, xenbus_get_node(dev), 1444 "virtual-device-ext", NULL, "%" PRIu32, &vdevice); 1445 if (error) { 1446 xenbus_dev_fatal(dev, error, "reading virtual-device"); 1447 device_printf(dev, "Couldn't determine virtual device.\n"); 1448 return (error); 1449 } 1450 1451 xbd_vdevice_to_unit(vdevice, &unit, &name); 1452 if (!strcmp(name, "xbd")) 1453 device_set_unit(dev, unit); 1454 1455 sc = device_get_softc(dev); 1456 mtx_init(&sc->xbd_io_lock, "blkfront i/o lock", NULL, MTX_DEF); 1457 xbd_initqs(sc); 1458 for (i = 0; i < XBD_MAX_RING_PAGES; i++) 1459 sc->xbd_ring_ref[i] = GRANT_REF_INVALID; 1460 1461 sc->xbd_dev = dev; 1462 sc->xbd_vdevice = vdevice; 1463 sc->xbd_state = XBD_STATE_DISCONNECTED; 1464 1465 xbd_setup_sysctl(sc); 1466 1467 /* Wait for backend device to publish its protocol capabilities. */ 1468 xenbus_set_state(dev, XenbusStateInitialising); 1469 1470 return (0); 1471 } 1472 1473 static int 1474 xbd_detach(device_t dev) 1475 { 1476 struct xbd_softc *sc = device_get_softc(dev); 1477 1478 DPRINTK("%s: %s removed\n", __func__, xenbus_get_node(dev)); 1479 1480 xbd_free(sc); 1481 mtx_destroy(&sc->xbd_io_lock); 1482 1483 return 0; 1484 } 1485 1486 static int 1487 xbd_suspend(device_t dev) 1488 { 1489 struct xbd_softc *sc = device_get_softc(dev); 1490 int retval; 1491 int saved_state; 1492 1493 /* Prevent new requests being issued until we fix things up. */ 1494 mtx_lock(&sc->xbd_io_lock); 1495 saved_state = sc->xbd_state; 1496 sc->xbd_state = XBD_STATE_SUSPENDED; 1497 1498 /* Wait for outstanding I/O to drain. */ 1499 retval = 0; 1500 while (xbd_queue_length(sc, XBD_Q_BUSY) != 0) { 1501 if (msleep(&sc->xbd_cm_q[XBD_Q_BUSY], &sc->xbd_io_lock, 1502 PRIBIO, "blkf_susp", 30 * hz) == EWOULDBLOCK) { 1503 retval = EBUSY; 1504 break; 1505 } 1506 } 1507 mtx_unlock(&sc->xbd_io_lock); 1508 1509 if (retval != 0) 1510 sc->xbd_state = saved_state; 1511 1512 return (retval); 1513 } 1514 1515 static int 1516 xbd_resume(device_t dev) 1517 { 1518 struct xbd_softc *sc = device_get_softc(dev); 1519 1520 DPRINTK("xbd_resume: %s\n", xenbus_get_node(dev)); 1521 1522 xbd_free(sc); 1523 xbd_initialize(sc); 1524 return (0); 1525 } 1526 1527 /** 1528 * Callback received when the backend's state changes. 1529 */ 1530 static void 1531 xbd_backend_changed(device_t dev, XenbusState backend_state) 1532 { 1533 struct xbd_softc *sc = device_get_softc(dev); 1534 1535 DPRINTK("backend_state=%d\n", backend_state); 1536 1537 switch (backend_state) { 1538 case XenbusStateUnknown: 1539 case XenbusStateInitialising: 1540 case XenbusStateReconfigured: 1541 case XenbusStateReconfiguring: 1542 case XenbusStateClosed: 1543 break; 1544 1545 case XenbusStateInitWait: 1546 case XenbusStateInitialised: 1547 xbd_initialize(sc); 1548 break; 1549 1550 case XenbusStateConnected: 1551 xbd_initialize(sc); 1552 xbd_connect(sc); 1553 break; 1554 1555 case XenbusStateClosing: 1556 if (sc->xbd_users > 0) 1557 xenbus_dev_error(dev, -EBUSY, 1558 "Device in use; refusing to close"); 1559 else 1560 xbd_closing(dev); 1561 break; 1562 } 1563 } 1564 1565 /*---------------------------- NewBus Registration ---------------------------*/ 1566 static device_method_t xbd_methods[] = { 1567 /* Device interface */ 1568 DEVMETHOD(device_probe, xbd_probe), 1569 DEVMETHOD(device_attach, xbd_attach), 1570 DEVMETHOD(device_detach, xbd_detach), 1571 DEVMETHOD(device_shutdown, bus_generic_shutdown), 1572 DEVMETHOD(device_suspend, xbd_suspend), 1573 DEVMETHOD(device_resume, xbd_resume), 1574 1575 /* Xenbus interface */ 1576 DEVMETHOD(xenbus_otherend_changed, xbd_backend_changed), 1577 1578 { 0, 0 } 1579 }; 1580 1581 static driver_t xbd_driver = { 1582 "xbd", 1583 xbd_methods, 1584 sizeof(struct xbd_softc), 1585 }; 1586 devclass_t xbd_devclass; 1587 1588 DRIVER_MODULE(xbd, xenbusb_front, xbd_driver, xbd_devclass, 0, 0); 1589