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 53 #include <xen/xen-os.h> 54 #include <xen/hypervisor.h> 55 #include <xen/xen_intr.h> 56 #include <xen/gnttab.h> 57 #include <xen/interface/grant_table.h> 58 #include <xen/interface/io/protocols.h> 59 #include <xen/xenbus/xenbusvar.h> 60 61 #include <machine/_inttypes.h> 62 63 #include <geom/geom_disk.h> 64 65 #include <dev/xen/blkfront/block.h> 66 67 #include "xenbus_if.h" 68 69 /*--------------------------- Forward Declarations ---------------------------*/ 70 static void xbd_closing(device_t); 71 static void xbd_startio(struct xbd_softc *sc); 72 73 /*---------------------------------- Macros ----------------------------------*/ 74 #if 0 75 #define DPRINTK(fmt, args...) printf("[XEN] %s:%d: " fmt ".\n", __func__, __LINE__, ##args) 76 #else 77 #define DPRINTK(fmt, args...) 78 #endif 79 80 #define XBD_SECTOR_SHFT 9 81 82 /*---------------------------- Global Static Data ----------------------------*/ 83 static MALLOC_DEFINE(M_XENBLOCKFRONT, "xbd", "Xen Block Front driver data"); 84 85 static int xbd_enable_indirect = 1; 86 SYSCTL_NODE(_hw, OID_AUTO, xbd, CTLFLAG_RD, 0, "xbd driver parameters"); 87 SYSCTL_INT(_hw_xbd, OID_AUTO, xbd_enable_indirect, CTLFLAG_RDTUN, 88 &xbd_enable_indirect, 0, "Enable xbd indirect segments"); 89 90 /*---------------------------- Command Processing ----------------------------*/ 91 static void 92 xbd_freeze(struct xbd_softc *sc, xbd_flag_t xbd_flag) 93 { 94 if (xbd_flag != XBDF_NONE && (sc->xbd_flags & xbd_flag) != 0) 95 return; 96 97 sc->xbd_flags |= xbd_flag; 98 sc->xbd_qfrozen_cnt++; 99 } 100 101 static void 102 xbd_thaw(struct xbd_softc *sc, xbd_flag_t xbd_flag) 103 { 104 if (xbd_flag != XBDF_NONE && (sc->xbd_flags & xbd_flag) == 0) 105 return; 106 107 if (sc->xbd_qfrozen_cnt == 0) 108 panic("%s: Thaw with flag 0x%x while not frozen.", 109 __func__, xbd_flag); 110 111 sc->xbd_flags &= ~xbd_flag; 112 sc->xbd_qfrozen_cnt--; 113 } 114 115 static void 116 xbd_cm_freeze(struct xbd_softc *sc, struct xbd_command *cm, xbdc_flag_t cm_flag) 117 { 118 if ((cm->cm_flags & XBDCF_FROZEN) != 0) 119 return; 120 121 cm->cm_flags |= XBDCF_FROZEN|cm_flag; 122 xbd_freeze(sc, XBDF_NONE); 123 } 124 125 static void 126 xbd_cm_thaw(struct xbd_softc *sc, struct xbd_command *cm) 127 { 128 if ((cm->cm_flags & XBDCF_FROZEN) == 0) 129 return; 130 131 cm->cm_flags &= ~XBDCF_FROZEN; 132 xbd_thaw(sc, XBDF_NONE); 133 } 134 135 static inline void 136 xbd_flush_requests(struct xbd_softc *sc) 137 { 138 int notify; 139 140 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&sc->xbd_ring, notify); 141 142 if (notify) 143 xen_intr_signal(sc->xen_intr_handle); 144 } 145 146 static void 147 xbd_free_command(struct xbd_command *cm) 148 { 149 150 KASSERT((cm->cm_flags & XBDCF_Q_MASK) == XBD_Q_NONE, 151 ("Freeing command that is still on queue %d.", 152 cm->cm_flags & XBDCF_Q_MASK)); 153 154 cm->cm_flags = XBDCF_INITIALIZER; 155 cm->cm_bp = NULL; 156 cm->cm_complete = NULL; 157 xbd_enqueue_cm(cm, XBD_Q_FREE); 158 xbd_thaw(cm->cm_sc, XBDF_CM_SHORTAGE); 159 } 160 161 static void 162 xbd_mksegarray(bus_dma_segment_t *segs, int nsegs, 163 grant_ref_t * gref_head, int otherend_id, int readonly, 164 grant_ref_t * sg_ref, struct blkif_request_segment *sg) 165 { 166 struct blkif_request_segment *last_block_sg = sg + nsegs; 167 vm_paddr_t buffer_ma; 168 uint64_t fsect, lsect; 169 int ref; 170 171 while (sg < last_block_sg) { 172 KASSERT(segs->ds_addr % (1 << XBD_SECTOR_SHFT) == 0, 173 ("XEN disk driver I/O must be sector aligned")); 174 KASSERT(segs->ds_len % (1 << XBD_SECTOR_SHFT) == 0, 175 ("XEN disk driver I/Os must be a multiple of " 176 "the sector length")); 177 buffer_ma = segs->ds_addr; 178 fsect = (buffer_ma & PAGE_MASK) >> XBD_SECTOR_SHFT; 179 lsect = fsect + (segs->ds_len >> XBD_SECTOR_SHFT) - 1; 180 181 KASSERT(lsect <= 7, ("XEN disk driver data cannot " 182 "cross a page boundary")); 183 184 /* install a grant reference. */ 185 ref = gnttab_claim_grant_reference(gref_head); 186 187 /* 188 * GNTTAB_LIST_END == 0xffffffff, but it is private 189 * to gnttab.c. 190 */ 191 KASSERT(ref != ~0, ("grant_reference failed")); 192 193 gnttab_grant_foreign_access_ref( 194 ref, 195 otherend_id, 196 buffer_ma >> PAGE_SHIFT, 197 readonly); 198 199 *sg_ref = ref; 200 *sg = (struct blkif_request_segment) { 201 .gref = ref, 202 .first_sect = fsect, 203 .last_sect = lsect 204 }; 205 sg++; 206 sg_ref++; 207 segs++; 208 } 209 } 210 211 static void 212 xbd_queue_cb(void *arg, bus_dma_segment_t *segs, int nsegs, int error) 213 { 214 struct xbd_softc *sc; 215 struct xbd_command *cm; 216 int op; 217 218 cm = arg; 219 sc = cm->cm_sc; 220 221 if (error) { 222 cm->cm_bp->bio_error = EIO; 223 biodone(cm->cm_bp); 224 xbd_free_command(cm); 225 return; 226 } 227 228 KASSERT(nsegs <= sc->xbd_max_request_segments, 229 ("Too many segments in a blkfront I/O")); 230 231 if (nsegs <= BLKIF_MAX_SEGMENTS_PER_REQUEST) { 232 blkif_request_t *ring_req; 233 234 /* Fill out a blkif_request_t structure. */ 235 ring_req = (blkif_request_t *) 236 RING_GET_REQUEST(&sc->xbd_ring, sc->xbd_ring.req_prod_pvt); 237 sc->xbd_ring.req_prod_pvt++; 238 ring_req->id = cm->cm_id; 239 ring_req->operation = cm->cm_operation; 240 ring_req->sector_number = cm->cm_sector_number; 241 ring_req->handle = (blkif_vdev_t)(uintptr_t)sc->xbd_disk; 242 ring_req->nr_segments = nsegs; 243 cm->cm_nseg = nsegs; 244 xbd_mksegarray(segs, nsegs, &cm->cm_gref_head, 245 xenbus_get_otherend_id(sc->xbd_dev), 246 cm->cm_operation == BLKIF_OP_WRITE, 247 cm->cm_sg_refs, ring_req->seg); 248 } else { 249 blkif_request_indirect_t *ring_req; 250 251 /* Fill out a blkif_request_indirect_t structure. */ 252 ring_req = (blkif_request_indirect_t *) 253 RING_GET_REQUEST(&sc->xbd_ring, sc->xbd_ring.req_prod_pvt); 254 sc->xbd_ring.req_prod_pvt++; 255 ring_req->id = cm->cm_id; 256 ring_req->operation = BLKIF_OP_INDIRECT; 257 ring_req->indirect_op = cm->cm_operation; 258 ring_req->sector_number = cm->cm_sector_number; 259 ring_req->handle = (blkif_vdev_t)(uintptr_t)sc->xbd_disk; 260 ring_req->nr_segments = nsegs; 261 cm->cm_nseg = nsegs; 262 xbd_mksegarray(segs, nsegs, &cm->cm_gref_head, 263 xenbus_get_otherend_id(sc->xbd_dev), 264 cm->cm_operation == BLKIF_OP_WRITE, 265 cm->cm_sg_refs, cm->cm_indirectionpages); 266 memcpy(ring_req->indirect_grefs, &cm->cm_indirectionrefs, 267 sizeof(grant_ref_t) * sc->xbd_max_request_indirectpages); 268 } 269 270 if (cm->cm_operation == BLKIF_OP_READ) 271 op = BUS_DMASYNC_PREREAD; 272 else if (cm->cm_operation == BLKIF_OP_WRITE) 273 op = BUS_DMASYNC_PREWRITE; 274 else 275 op = 0; 276 bus_dmamap_sync(sc->xbd_io_dmat, cm->cm_map, op); 277 278 gnttab_free_grant_references(cm->cm_gref_head); 279 280 xbd_enqueue_cm(cm, XBD_Q_BUSY); 281 282 /* 283 * If bus dma had to asynchronously call us back to dispatch 284 * this command, we are no longer executing in the context of 285 * xbd_startio(). Thus we cannot rely on xbd_startio()'s call to 286 * xbd_flush_requests() to publish this command to the backend 287 * along with any other commands that it could batch. 288 */ 289 if ((cm->cm_flags & XBDCF_ASYNC_MAPPING) != 0) 290 xbd_flush_requests(sc); 291 292 return; 293 } 294 295 static int 296 xbd_queue_request(struct xbd_softc *sc, struct xbd_command *cm) 297 { 298 int error; 299 300 if (cm->cm_bp != NULL) 301 error = bus_dmamap_load_bio(sc->xbd_io_dmat, cm->cm_map, 302 cm->cm_bp, xbd_queue_cb, cm, 0); 303 else 304 error = bus_dmamap_load(sc->xbd_io_dmat, cm->cm_map, 305 cm->cm_data, cm->cm_datalen, xbd_queue_cb, cm, 0); 306 if (error == EINPROGRESS) { 307 /* 308 * Maintain queuing order by freezing the queue. The next 309 * command may not require as many resources as the command 310 * we just attempted to map, so we can't rely on bus dma 311 * blocking for it too. 312 */ 313 xbd_cm_freeze(sc, cm, XBDCF_ASYNC_MAPPING); 314 return (0); 315 } 316 317 return (error); 318 } 319 320 static void 321 xbd_restart_queue_callback(void *arg) 322 { 323 struct xbd_softc *sc = arg; 324 325 mtx_lock(&sc->xbd_io_lock); 326 327 xbd_thaw(sc, XBDF_GNT_SHORTAGE); 328 329 xbd_startio(sc); 330 331 mtx_unlock(&sc->xbd_io_lock); 332 } 333 334 static struct xbd_command * 335 xbd_bio_command(struct xbd_softc *sc) 336 { 337 struct xbd_command *cm; 338 struct bio *bp; 339 340 if (__predict_false(sc->xbd_state != XBD_STATE_CONNECTED)) 341 return (NULL); 342 343 bp = xbd_dequeue_bio(sc); 344 if (bp == NULL) 345 return (NULL); 346 347 if ((cm = xbd_dequeue_cm(sc, XBD_Q_FREE)) == NULL) { 348 xbd_freeze(sc, XBDF_CM_SHORTAGE); 349 xbd_requeue_bio(sc, bp); 350 return (NULL); 351 } 352 353 if (gnttab_alloc_grant_references(sc->xbd_max_request_segments, 354 &cm->cm_gref_head) != 0) { 355 gnttab_request_free_callback(&sc->xbd_callback, 356 xbd_restart_queue_callback, sc, 357 sc->xbd_max_request_segments); 358 xbd_freeze(sc, XBDF_GNT_SHORTAGE); 359 xbd_requeue_bio(sc, bp); 360 xbd_enqueue_cm(cm, XBD_Q_FREE); 361 return (NULL); 362 } 363 364 cm->cm_bp = bp; 365 cm->cm_sector_number = (blkif_sector_t)bp->bio_pblkno; 366 367 switch (bp->bio_cmd) { 368 case BIO_READ: 369 cm->cm_operation = BLKIF_OP_READ; 370 break; 371 case BIO_WRITE: 372 cm->cm_operation = BLKIF_OP_WRITE; 373 if ((bp->bio_flags & BIO_ORDERED) != 0) { 374 if ((sc->xbd_flags & XBDF_BARRIER) != 0) { 375 cm->cm_operation = BLKIF_OP_WRITE_BARRIER; 376 } else { 377 /* 378 * Single step this command. 379 */ 380 cm->cm_flags |= XBDCF_Q_FREEZE; 381 if (xbd_queue_length(sc, XBD_Q_BUSY) != 0) { 382 /* 383 * Wait for in-flight requests to 384 * finish. 385 */ 386 xbd_freeze(sc, XBDF_WAIT_IDLE); 387 xbd_requeue_cm(cm, XBD_Q_READY); 388 return (NULL); 389 } 390 } 391 } 392 break; 393 case BIO_FLUSH: 394 if ((sc->xbd_flags & XBDF_FLUSH) != 0) 395 cm->cm_operation = BLKIF_OP_FLUSH_DISKCACHE; 396 else if ((sc->xbd_flags & XBDF_BARRIER) != 0) 397 cm->cm_operation = BLKIF_OP_WRITE_BARRIER; 398 else 399 panic("flush request, but no flush support available"); 400 break; 401 default: 402 biofinish(bp, NULL, EOPNOTSUPP); 403 xbd_enqueue_cm(cm, XBD_Q_FREE); 404 return (NULL); 405 } 406 407 return (cm); 408 } 409 410 /* 411 * Dequeue buffers and place them in the shared communication ring. 412 * Return when no more requests can be accepted or all buffers have 413 * been queued. 414 * 415 * Signal XEN once the ring has been filled out. 416 */ 417 static void 418 xbd_startio(struct xbd_softc *sc) 419 { 420 struct xbd_command *cm; 421 int error, queued = 0; 422 423 mtx_assert(&sc->xbd_io_lock, MA_OWNED); 424 425 if (sc->xbd_state != XBD_STATE_CONNECTED) 426 return; 427 428 while (!RING_FULL(&sc->xbd_ring)) { 429 430 if (sc->xbd_qfrozen_cnt != 0) 431 break; 432 433 cm = xbd_dequeue_cm(sc, XBD_Q_READY); 434 435 if (cm == NULL) 436 cm = xbd_bio_command(sc); 437 438 if (cm == NULL) 439 break; 440 441 if ((cm->cm_flags & XBDCF_Q_FREEZE) != 0) { 442 /* 443 * Single step command. Future work is 444 * held off until this command completes. 445 */ 446 xbd_cm_freeze(sc, cm, XBDCF_Q_FREEZE); 447 } 448 449 if ((error = xbd_queue_request(sc, cm)) != 0) { 450 printf("xbd_queue_request returned %d\n", error); 451 break; 452 } 453 queued++; 454 } 455 456 if (queued != 0) 457 xbd_flush_requests(sc); 458 } 459 460 static void 461 xbd_bio_complete(struct xbd_softc *sc, struct xbd_command *cm) 462 { 463 struct bio *bp; 464 465 bp = cm->cm_bp; 466 467 if (__predict_false(cm->cm_status != BLKIF_RSP_OKAY)) { 468 disk_err(bp, "disk error" , -1, 0); 469 printf(" status: %x\n", cm->cm_status); 470 bp->bio_flags |= BIO_ERROR; 471 } 472 473 if (bp->bio_flags & BIO_ERROR) 474 bp->bio_error = EIO; 475 else 476 bp->bio_resid = 0; 477 478 xbd_free_command(cm); 479 biodone(bp); 480 } 481 482 static void 483 xbd_int(void *xsc) 484 { 485 struct xbd_softc *sc = xsc; 486 struct xbd_command *cm; 487 blkif_response_t *bret; 488 RING_IDX i, rp; 489 int op; 490 491 mtx_lock(&sc->xbd_io_lock); 492 493 if (__predict_false(sc->xbd_state == XBD_STATE_DISCONNECTED)) { 494 mtx_unlock(&sc->xbd_io_lock); 495 return; 496 } 497 498 again: 499 rp = sc->xbd_ring.sring->rsp_prod; 500 rmb(); /* Ensure we see queued responses up to 'rp'. */ 501 502 for (i = sc->xbd_ring.rsp_cons; i != rp;) { 503 bret = RING_GET_RESPONSE(&sc->xbd_ring, i); 504 cm = &sc->xbd_shadow[bret->id]; 505 506 xbd_remove_cm(cm, XBD_Q_BUSY); 507 gnttab_end_foreign_access_references(cm->cm_nseg, 508 cm->cm_sg_refs); 509 i++; 510 511 if (cm->cm_operation == BLKIF_OP_READ) 512 op = BUS_DMASYNC_POSTREAD; 513 else if (cm->cm_operation == BLKIF_OP_WRITE || 514 cm->cm_operation == BLKIF_OP_WRITE_BARRIER) 515 op = BUS_DMASYNC_POSTWRITE; 516 else 517 op = 0; 518 bus_dmamap_sync(sc->xbd_io_dmat, cm->cm_map, op); 519 bus_dmamap_unload(sc->xbd_io_dmat, cm->cm_map); 520 521 /* 522 * Release any hold this command has on future command 523 * dispatch. 524 */ 525 xbd_cm_thaw(sc, cm); 526 527 /* 528 * Directly call the i/o complete routine to save an 529 * an indirection in the common case. 530 */ 531 cm->cm_status = bret->status; 532 if (cm->cm_bp) 533 xbd_bio_complete(sc, cm); 534 else if (cm->cm_complete != NULL) 535 cm->cm_complete(cm); 536 else 537 xbd_free_command(cm); 538 } 539 540 sc->xbd_ring.rsp_cons = i; 541 542 if (i != sc->xbd_ring.req_prod_pvt) { 543 int more_to_do; 544 RING_FINAL_CHECK_FOR_RESPONSES(&sc->xbd_ring, more_to_do); 545 if (more_to_do) 546 goto again; 547 } else { 548 sc->xbd_ring.sring->rsp_event = i + 1; 549 } 550 551 if (xbd_queue_length(sc, XBD_Q_BUSY) == 0) 552 xbd_thaw(sc, XBDF_WAIT_IDLE); 553 554 xbd_startio(sc); 555 556 if (__predict_false(sc->xbd_state == XBD_STATE_SUSPENDED)) 557 wakeup(&sc->xbd_cm_q[XBD_Q_BUSY]); 558 559 mtx_unlock(&sc->xbd_io_lock); 560 } 561 562 /*------------------------------- Dump Support -------------------------------*/ 563 /** 564 * Quiesce the disk writes for a dump file before allowing the next buffer. 565 */ 566 static void 567 xbd_quiesce(struct xbd_softc *sc) 568 { 569 int mtd; 570 571 // While there are outstanding requests 572 while (xbd_queue_length(sc, XBD_Q_BUSY) != 0) { 573 RING_FINAL_CHECK_FOR_RESPONSES(&sc->xbd_ring, mtd); 574 if (mtd) { 575 /* Received request completions, update queue. */ 576 xbd_int(sc); 577 } 578 if (xbd_queue_length(sc, XBD_Q_BUSY) != 0) { 579 /* 580 * Still pending requests, wait for the disk i/o 581 * to complete. 582 */ 583 HYPERVISOR_yield(); 584 } 585 } 586 } 587 588 /* Kernel dump function for a paravirtualized disk device */ 589 static void 590 xbd_dump_complete(struct xbd_command *cm) 591 { 592 593 xbd_enqueue_cm(cm, XBD_Q_COMPLETE); 594 } 595 596 static int 597 xbd_dump(void *arg, void *virtual, vm_offset_t physical, off_t offset, 598 size_t length) 599 { 600 struct disk *dp = arg; 601 struct xbd_softc *sc = dp->d_drv1; 602 struct xbd_command *cm; 603 size_t chunk; 604 int sbp; 605 int rc = 0; 606 607 if (length == 0) 608 return (0); 609 610 xbd_quiesce(sc); /* All quiet on the western front. */ 611 612 /* 613 * If this lock is held, then this module is failing, and a 614 * successful kernel dump is highly unlikely anyway. 615 */ 616 mtx_lock(&sc->xbd_io_lock); 617 618 /* Split the 64KB block as needed */ 619 for (sbp=0; length > 0; sbp++) { 620 cm = xbd_dequeue_cm(sc, XBD_Q_FREE); 621 if (cm == NULL) { 622 mtx_unlock(&sc->xbd_io_lock); 623 device_printf(sc->xbd_dev, "dump: no more commands?\n"); 624 return (EBUSY); 625 } 626 627 if (gnttab_alloc_grant_references(sc->xbd_max_request_segments, 628 &cm->cm_gref_head) != 0) { 629 xbd_free_command(cm); 630 mtx_unlock(&sc->xbd_io_lock); 631 device_printf(sc->xbd_dev, "no more grant allocs?\n"); 632 return (EBUSY); 633 } 634 635 chunk = length > sc->xbd_max_request_size ? 636 sc->xbd_max_request_size : length; 637 cm->cm_data = virtual; 638 cm->cm_datalen = chunk; 639 cm->cm_operation = BLKIF_OP_WRITE; 640 cm->cm_sector_number = offset / dp->d_sectorsize; 641 cm->cm_complete = xbd_dump_complete; 642 643 xbd_enqueue_cm(cm, XBD_Q_READY); 644 645 length -= chunk; 646 offset += chunk; 647 virtual = (char *) virtual + chunk; 648 } 649 650 /* Tell DOM0 to do the I/O */ 651 xbd_startio(sc); 652 mtx_unlock(&sc->xbd_io_lock); 653 654 /* Poll for the completion. */ 655 xbd_quiesce(sc); /* All quite on the eastern front */ 656 657 /* If there were any errors, bail out... */ 658 while ((cm = xbd_dequeue_cm(sc, XBD_Q_COMPLETE)) != NULL) { 659 if (cm->cm_status != BLKIF_RSP_OKAY) { 660 device_printf(sc->xbd_dev, 661 "Dump I/O failed at sector %jd\n", 662 cm->cm_sector_number); 663 rc = EIO; 664 } 665 xbd_free_command(cm); 666 } 667 668 return (rc); 669 } 670 671 /*----------------------------- Disk Entrypoints -----------------------------*/ 672 static int 673 xbd_open(struct disk *dp) 674 { 675 struct xbd_softc *sc = dp->d_drv1; 676 677 if (sc == NULL) { 678 printf("xbd%d: not found", dp->d_unit); 679 return (ENXIO); 680 } 681 682 sc->xbd_flags |= XBDF_OPEN; 683 sc->xbd_users++; 684 return (0); 685 } 686 687 static int 688 xbd_close(struct disk *dp) 689 { 690 struct xbd_softc *sc = dp->d_drv1; 691 692 if (sc == NULL) 693 return (ENXIO); 694 sc->xbd_flags &= ~XBDF_OPEN; 695 if (--(sc->xbd_users) == 0) { 696 /* 697 * Check whether we have been instructed to close. We will 698 * have ignored this request initially, as the device was 699 * still mounted. 700 */ 701 if (xenbus_get_otherend_state(sc->xbd_dev) == 702 XenbusStateClosing) 703 xbd_closing(sc->xbd_dev); 704 } 705 return (0); 706 } 707 708 static int 709 xbd_ioctl(struct disk *dp, u_long cmd, void *addr, int flag, struct thread *td) 710 { 711 struct xbd_softc *sc = dp->d_drv1; 712 713 if (sc == NULL) 714 return (ENXIO); 715 716 return (ENOTTY); 717 } 718 719 /* 720 * Read/write routine for a buffer. Finds the proper unit, place it on 721 * the sortq and kick the controller. 722 */ 723 static void 724 xbd_strategy(struct bio *bp) 725 { 726 struct xbd_softc *sc = bp->bio_disk->d_drv1; 727 728 /* bogus disk? */ 729 if (sc == NULL) { 730 bp->bio_error = EINVAL; 731 bp->bio_flags |= BIO_ERROR; 732 bp->bio_resid = bp->bio_bcount; 733 biodone(bp); 734 return; 735 } 736 737 /* 738 * Place it in the queue of disk activities for this disk 739 */ 740 mtx_lock(&sc->xbd_io_lock); 741 742 xbd_enqueue_bio(sc, bp); 743 xbd_startio(sc); 744 745 mtx_unlock(&sc->xbd_io_lock); 746 return; 747 } 748 749 /*------------------------------ Ring Management -----------------------------*/ 750 static int 751 xbd_alloc_ring(struct xbd_softc *sc) 752 { 753 blkif_sring_t *sring; 754 uintptr_t sring_page_addr; 755 int error; 756 int i; 757 758 sring = malloc(sc->xbd_ring_pages * PAGE_SIZE, M_XENBLOCKFRONT, 759 M_NOWAIT|M_ZERO); 760 if (sring == NULL) { 761 xenbus_dev_fatal(sc->xbd_dev, ENOMEM, "allocating shared ring"); 762 return (ENOMEM); 763 } 764 SHARED_RING_INIT(sring); 765 FRONT_RING_INIT(&sc->xbd_ring, sring, sc->xbd_ring_pages * PAGE_SIZE); 766 767 for (i = 0, sring_page_addr = (uintptr_t)sring; 768 i < sc->xbd_ring_pages; 769 i++, sring_page_addr += PAGE_SIZE) { 770 771 error = xenbus_grant_ring(sc->xbd_dev, 772 (vtophys(sring_page_addr) >> PAGE_SHIFT), 773 &sc->xbd_ring_ref[i]); 774 if (error) { 775 xenbus_dev_fatal(sc->xbd_dev, error, 776 "granting ring_ref(%d)", i); 777 return (error); 778 } 779 } 780 if (sc->xbd_ring_pages == 1) { 781 error = xs_printf(XST_NIL, xenbus_get_node(sc->xbd_dev), 782 "ring-ref", "%u", sc->xbd_ring_ref[0]); 783 if (error) { 784 xenbus_dev_fatal(sc->xbd_dev, error, 785 "writing %s/ring-ref", 786 xenbus_get_node(sc->xbd_dev)); 787 return (error); 788 } 789 } else { 790 for (i = 0; i < sc->xbd_ring_pages; i++) { 791 char ring_ref_name[]= "ring_refXX"; 792 793 snprintf(ring_ref_name, sizeof(ring_ref_name), 794 "ring-ref%u", i); 795 error = xs_printf(XST_NIL, xenbus_get_node(sc->xbd_dev), 796 ring_ref_name, "%u", sc->xbd_ring_ref[i]); 797 if (error) { 798 xenbus_dev_fatal(sc->xbd_dev, error, 799 "writing %s/%s", 800 xenbus_get_node(sc->xbd_dev), 801 ring_ref_name); 802 return (error); 803 } 804 } 805 } 806 807 error = xen_intr_alloc_and_bind_local_port(sc->xbd_dev, 808 xenbus_get_otherend_id(sc->xbd_dev), NULL, xbd_int, sc, 809 INTR_TYPE_BIO | INTR_MPSAFE, &sc->xen_intr_handle); 810 if (error) { 811 xenbus_dev_fatal(sc->xbd_dev, error, 812 "xen_intr_alloc_and_bind_local_port failed"); 813 return (error); 814 } 815 816 return (0); 817 } 818 819 static void 820 xbd_free_ring(struct xbd_softc *sc) 821 { 822 int i; 823 824 if (sc->xbd_ring.sring == NULL) 825 return; 826 827 for (i = 0; i < sc->xbd_ring_pages; i++) { 828 if (sc->xbd_ring_ref[i] != GRANT_REF_INVALID) { 829 gnttab_end_foreign_access_ref(sc->xbd_ring_ref[i]); 830 sc->xbd_ring_ref[i] = GRANT_REF_INVALID; 831 } 832 } 833 free(sc->xbd_ring.sring, M_XENBLOCKFRONT); 834 sc->xbd_ring.sring = NULL; 835 } 836 837 /*-------------------------- Initialization/Teardown -------------------------*/ 838 static int 839 xbd_feature_string(struct xbd_softc *sc, char *features, size_t len) 840 { 841 struct sbuf sb; 842 int feature_cnt; 843 844 sbuf_new(&sb, features, len, SBUF_FIXEDLEN); 845 846 feature_cnt = 0; 847 if ((sc->xbd_flags & XBDF_FLUSH) != 0) { 848 sbuf_printf(&sb, "flush"); 849 feature_cnt++; 850 } 851 852 if ((sc->xbd_flags & XBDF_BARRIER) != 0) { 853 if (feature_cnt != 0) 854 sbuf_printf(&sb, ", "); 855 sbuf_printf(&sb, "write_barrier"); 856 feature_cnt++; 857 } 858 859 if ((sc->xbd_flags & XBDF_DISCARD) != 0) { 860 if (feature_cnt != 0) 861 sbuf_printf(&sb, ", "); 862 sbuf_printf(&sb, "discard"); 863 feature_cnt++; 864 } 865 866 if ((sc->xbd_flags & XBDF_PERSISTENT) != 0) { 867 if (feature_cnt != 0) 868 sbuf_printf(&sb, ", "); 869 sbuf_printf(&sb, "persistent_grants"); 870 feature_cnt++; 871 } 872 873 (void) sbuf_finish(&sb); 874 return (sbuf_len(&sb)); 875 } 876 877 static int 878 xbd_sysctl_features(SYSCTL_HANDLER_ARGS) 879 { 880 char features[80]; 881 struct xbd_softc *sc = arg1; 882 int error; 883 int len; 884 885 error = sysctl_wire_old_buffer(req, 0); 886 if (error != 0) 887 return (error); 888 889 len = xbd_feature_string(sc, features, sizeof(features)); 890 891 /* len is -1 on error, which will make the SYSCTL_OUT a no-op. */ 892 return (SYSCTL_OUT(req, features, len + 1/*NUL*/)); 893 } 894 895 static void 896 xbd_setup_sysctl(struct xbd_softc *xbd) 897 { 898 struct sysctl_ctx_list *sysctl_ctx = NULL; 899 struct sysctl_oid *sysctl_tree = NULL; 900 struct sysctl_oid_list *children; 901 902 sysctl_ctx = device_get_sysctl_ctx(xbd->xbd_dev); 903 if (sysctl_ctx == NULL) 904 return; 905 906 sysctl_tree = device_get_sysctl_tree(xbd->xbd_dev); 907 if (sysctl_tree == NULL) 908 return; 909 910 children = SYSCTL_CHILDREN(sysctl_tree); 911 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 912 "max_requests", CTLFLAG_RD, &xbd->xbd_max_requests, -1, 913 "maximum outstanding requests (negotiated)"); 914 915 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 916 "max_request_segments", CTLFLAG_RD, 917 &xbd->xbd_max_request_segments, 0, 918 "maximum number of pages per requests (negotiated)"); 919 920 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 921 "max_request_size", CTLFLAG_RD, &xbd->xbd_max_request_size, 0, 922 "maximum size in bytes of a request (negotiated)"); 923 924 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO, 925 "ring_pages", CTLFLAG_RD, &xbd->xbd_ring_pages, 0, 926 "communication channel pages (negotiated)"); 927 928 SYSCTL_ADD_PROC(sysctl_ctx, children, OID_AUTO, 929 "features", CTLTYPE_STRING|CTLFLAG_RD, xbd, 0, 930 xbd_sysctl_features, "A", "protocol features (negotiated)"); 931 } 932 933 /* 934 * Translate Linux major/minor to an appropriate name and unit 935 * number. For HVM guests, this allows us to use the same drive names 936 * with blkfront as the emulated drives, easing transition slightly. 937 */ 938 static void 939 xbd_vdevice_to_unit(uint32_t vdevice, int *unit, const char **name) 940 { 941 static struct vdev_info { 942 int major; 943 int shift; 944 int base; 945 const char *name; 946 } info[] = { 947 {3, 6, 0, "ada"}, /* ide0 */ 948 {22, 6, 2, "ada"}, /* ide1 */ 949 {33, 6, 4, "ada"}, /* ide2 */ 950 {34, 6, 6, "ada"}, /* ide3 */ 951 {56, 6, 8, "ada"}, /* ide4 */ 952 {57, 6, 10, "ada"}, /* ide5 */ 953 {88, 6, 12, "ada"}, /* ide6 */ 954 {89, 6, 14, "ada"}, /* ide7 */ 955 {90, 6, 16, "ada"}, /* ide8 */ 956 {91, 6, 18, "ada"}, /* ide9 */ 957 958 {8, 4, 0, "da"}, /* scsi disk0 */ 959 {65, 4, 16, "da"}, /* scsi disk1 */ 960 {66, 4, 32, "da"}, /* scsi disk2 */ 961 {67, 4, 48, "da"}, /* scsi disk3 */ 962 {68, 4, 64, "da"}, /* scsi disk4 */ 963 {69, 4, 80, "da"}, /* scsi disk5 */ 964 {70, 4, 96, "da"}, /* scsi disk6 */ 965 {71, 4, 112, "da"}, /* scsi disk7 */ 966 {128, 4, 128, "da"}, /* scsi disk8 */ 967 {129, 4, 144, "da"}, /* scsi disk9 */ 968 {130, 4, 160, "da"}, /* scsi disk10 */ 969 {131, 4, 176, "da"}, /* scsi disk11 */ 970 {132, 4, 192, "da"}, /* scsi disk12 */ 971 {133, 4, 208, "da"}, /* scsi disk13 */ 972 {134, 4, 224, "da"}, /* scsi disk14 */ 973 {135, 4, 240, "da"}, /* scsi disk15 */ 974 975 {202, 4, 0, "xbd"}, /* xbd */ 976 977 {0, 0, 0, NULL}, 978 }; 979 int major = vdevice >> 8; 980 int minor = vdevice & 0xff; 981 int i; 982 983 if (vdevice & (1 << 28)) { 984 *unit = (vdevice & ((1 << 28) - 1)) >> 8; 985 *name = "xbd"; 986 return; 987 } 988 989 for (i = 0; info[i].major; i++) { 990 if (info[i].major == major) { 991 *unit = info[i].base + (minor >> info[i].shift); 992 *name = info[i].name; 993 return; 994 } 995 } 996 997 *unit = minor >> 4; 998 *name = "xbd"; 999 } 1000 1001 int 1002 xbd_instance_create(struct xbd_softc *sc, blkif_sector_t sectors, 1003 int vdevice, uint16_t vdisk_info, unsigned long sector_size, 1004 unsigned long phys_sector_size) 1005 { 1006 char features[80]; 1007 int unit, error = 0; 1008 const char *name; 1009 1010 xbd_vdevice_to_unit(vdevice, &unit, &name); 1011 1012 sc->xbd_unit = unit; 1013 1014 if (strcmp(name, "xbd") != 0) 1015 device_printf(sc->xbd_dev, "attaching as %s%d\n", name, unit); 1016 1017 if (xbd_feature_string(sc, features, sizeof(features)) > 0) { 1018 device_printf(sc->xbd_dev, "features: %s\n", 1019 features); 1020 } 1021 1022 sc->xbd_disk = disk_alloc(); 1023 sc->xbd_disk->d_unit = sc->xbd_unit; 1024 sc->xbd_disk->d_open = xbd_open; 1025 sc->xbd_disk->d_close = xbd_close; 1026 sc->xbd_disk->d_ioctl = xbd_ioctl; 1027 sc->xbd_disk->d_strategy = xbd_strategy; 1028 sc->xbd_disk->d_dump = xbd_dump; 1029 sc->xbd_disk->d_name = name; 1030 sc->xbd_disk->d_drv1 = sc; 1031 sc->xbd_disk->d_sectorsize = sector_size; 1032 sc->xbd_disk->d_stripesize = phys_sector_size; 1033 sc->xbd_disk->d_stripeoffset = 0; 1034 1035 sc->xbd_disk->d_mediasize = sectors * sector_size; 1036 sc->xbd_disk->d_maxsize = sc->xbd_max_request_size; 1037 sc->xbd_disk->d_flags = DISKFLAG_UNMAPPED_BIO; 1038 if ((sc->xbd_flags & (XBDF_FLUSH|XBDF_BARRIER)) != 0) { 1039 sc->xbd_disk->d_flags |= DISKFLAG_CANFLUSHCACHE; 1040 device_printf(sc->xbd_dev, 1041 "synchronize cache commands enabled.\n"); 1042 } 1043 disk_create(sc->xbd_disk, DISK_VERSION); 1044 1045 return error; 1046 } 1047 1048 static void 1049 xbd_free(struct xbd_softc *sc) 1050 { 1051 int i; 1052 1053 /* Prevent new requests being issued until we fix things up. */ 1054 mtx_lock(&sc->xbd_io_lock); 1055 sc->xbd_state = XBD_STATE_DISCONNECTED; 1056 mtx_unlock(&sc->xbd_io_lock); 1057 1058 /* Free resources associated with old device channel. */ 1059 xbd_free_ring(sc); 1060 if (sc->xbd_shadow) { 1061 1062 for (i = 0; i < sc->xbd_max_requests; i++) { 1063 struct xbd_command *cm; 1064 1065 cm = &sc->xbd_shadow[i]; 1066 if (cm->cm_sg_refs != NULL) { 1067 free(cm->cm_sg_refs, M_XENBLOCKFRONT); 1068 cm->cm_sg_refs = NULL; 1069 } 1070 1071 if (cm->cm_indirectionpages != NULL) { 1072 gnttab_end_foreign_access_references( 1073 sc->xbd_max_request_indirectpages, 1074 &cm->cm_indirectionrefs[0]); 1075 contigfree(cm->cm_indirectionpages, PAGE_SIZE * 1076 sc->xbd_max_request_indirectpages, 1077 M_XENBLOCKFRONT); 1078 cm->cm_indirectionpages = NULL; 1079 } 1080 1081 bus_dmamap_destroy(sc->xbd_io_dmat, cm->cm_map); 1082 } 1083 free(sc->xbd_shadow, M_XENBLOCKFRONT); 1084 sc->xbd_shadow = NULL; 1085 1086 bus_dma_tag_destroy(sc->xbd_io_dmat); 1087 1088 xbd_initq_cm(sc, XBD_Q_FREE); 1089 xbd_initq_cm(sc, XBD_Q_READY); 1090 xbd_initq_cm(sc, XBD_Q_COMPLETE); 1091 } 1092 1093 xen_intr_unbind(&sc->xen_intr_handle); 1094 1095 } 1096 1097 /*--------------------------- State Change Handlers --------------------------*/ 1098 static void 1099 xbd_initialize(struct xbd_softc *sc) 1100 { 1101 const char *otherend_path; 1102 const char *node_path; 1103 uint32_t max_ring_page_order; 1104 int error; 1105 1106 if (xenbus_get_state(sc->xbd_dev) != XenbusStateInitialising) { 1107 /* Initialization has already been performed. */ 1108 return; 1109 } 1110 1111 /* 1112 * Protocol defaults valid even if negotiation for a 1113 * setting fails. 1114 */ 1115 max_ring_page_order = 0; 1116 sc->xbd_ring_pages = 1; 1117 1118 /* 1119 * Protocol negotiation. 1120 * 1121 * \note xs_gather() returns on the first encountered error, so 1122 * we must use independent calls in order to guarantee 1123 * we don't miss information in a sparsly populated back-end 1124 * tree. 1125 * 1126 * \note xs_scanf() does not update variables for unmatched 1127 * fields. 1128 */ 1129 otherend_path = xenbus_get_otherend_path(sc->xbd_dev); 1130 node_path = xenbus_get_node(sc->xbd_dev); 1131 1132 /* Support both backend schemes for relaying ring page limits. */ 1133 (void)xs_scanf(XST_NIL, otherend_path, 1134 "max-ring-page-order", NULL, "%" PRIu32, 1135 &max_ring_page_order); 1136 sc->xbd_ring_pages = 1 << max_ring_page_order; 1137 (void)xs_scanf(XST_NIL, otherend_path, 1138 "max-ring-pages", NULL, "%" PRIu32, 1139 &sc->xbd_ring_pages); 1140 if (sc->xbd_ring_pages < 1) 1141 sc->xbd_ring_pages = 1; 1142 1143 if (sc->xbd_ring_pages > XBD_MAX_RING_PAGES) { 1144 device_printf(sc->xbd_dev, 1145 "Back-end specified ring-pages of %u " 1146 "limited to front-end limit of %u.\n", 1147 sc->xbd_ring_pages, XBD_MAX_RING_PAGES); 1148 sc->xbd_ring_pages = XBD_MAX_RING_PAGES; 1149 } 1150 1151 if (powerof2(sc->xbd_ring_pages) == 0) { 1152 uint32_t new_page_limit; 1153 1154 new_page_limit = 0x01 << (fls(sc->xbd_ring_pages) - 1); 1155 device_printf(sc->xbd_dev, 1156 "Back-end specified ring-pages of %u " 1157 "is not a power of 2. Limited to %u.\n", 1158 sc->xbd_ring_pages, new_page_limit); 1159 sc->xbd_ring_pages = new_page_limit; 1160 } 1161 1162 sc->xbd_max_requests = 1163 BLKIF_MAX_RING_REQUESTS(sc->xbd_ring_pages * PAGE_SIZE); 1164 if (sc->xbd_max_requests > XBD_MAX_REQUESTS) { 1165 device_printf(sc->xbd_dev, 1166 "Back-end specified max_requests of %u " 1167 "limited to front-end limit of %zu.\n", 1168 sc->xbd_max_requests, XBD_MAX_REQUESTS); 1169 sc->xbd_max_requests = XBD_MAX_REQUESTS; 1170 } 1171 1172 if (xbd_alloc_ring(sc) != 0) 1173 return; 1174 1175 /* Support both backend schemes for relaying ring page limits. */ 1176 if (sc->xbd_ring_pages > 1) { 1177 error = xs_printf(XST_NIL, node_path, 1178 "num-ring-pages","%u", 1179 sc->xbd_ring_pages); 1180 if (error) { 1181 xenbus_dev_fatal(sc->xbd_dev, error, 1182 "writing %s/num-ring-pages", 1183 node_path); 1184 return; 1185 } 1186 1187 error = xs_printf(XST_NIL, node_path, 1188 "ring-page-order", "%u", 1189 fls(sc->xbd_ring_pages) - 1); 1190 if (error) { 1191 xenbus_dev_fatal(sc->xbd_dev, error, 1192 "writing %s/ring-page-order", 1193 node_path); 1194 return; 1195 } 1196 } 1197 1198 error = xs_printf(XST_NIL, node_path, "event-channel", 1199 "%u", xen_intr_port(sc->xen_intr_handle)); 1200 if (error) { 1201 xenbus_dev_fatal(sc->xbd_dev, error, 1202 "writing %s/event-channel", 1203 node_path); 1204 return; 1205 } 1206 1207 error = xs_printf(XST_NIL, node_path, "protocol", 1208 "%s", XEN_IO_PROTO_ABI_NATIVE); 1209 if (error) { 1210 xenbus_dev_fatal(sc->xbd_dev, error, 1211 "writing %s/protocol", 1212 node_path); 1213 return; 1214 } 1215 1216 xenbus_set_state(sc->xbd_dev, XenbusStateInitialised); 1217 } 1218 1219 /* 1220 * Invoked when the backend is finally 'ready' (and has published 1221 * the details about the physical device - #sectors, size, etc). 1222 */ 1223 static void 1224 xbd_connect(struct xbd_softc *sc) 1225 { 1226 device_t dev = sc->xbd_dev; 1227 unsigned long sectors, sector_size, phys_sector_size; 1228 unsigned int binfo; 1229 int err, feature_barrier, feature_flush; 1230 int i, j; 1231 1232 DPRINTK("blkfront.c:connect:%s.\n", xenbus_get_otherend_path(dev)); 1233 1234 if (sc->xbd_state == XBD_STATE_SUSPENDED) { 1235 return; 1236 } 1237 1238 if (sc->xbd_state == XBD_STATE_CONNECTED) { 1239 struct disk *disk; 1240 1241 disk = sc->xbd_disk; 1242 if (disk == NULL) { 1243 return; 1244 } 1245 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev), 1246 "sectors", "%lu", §ors, NULL); 1247 if (err != 0) { 1248 xenbus_dev_error(dev, err, 1249 "reading sectors at %s", 1250 xenbus_get_otherend_path(dev)); 1251 return; 1252 } 1253 disk->d_mediasize = disk->d_sectorsize * sectors; 1254 err = disk_resize(disk, M_NOWAIT); 1255 if (err) { 1256 xenbus_dev_error(dev, err, 1257 "unable to resize disk %s%u", 1258 disk->d_name, disk->d_unit); 1259 return; 1260 } 1261 device_printf(sc->xbd_dev, 1262 "changed capacity to %jd\n", 1263 (intmax_t)disk->d_mediasize); 1264 return; 1265 } 1266 1267 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev), 1268 "sectors", "%lu", §ors, 1269 "info", "%u", &binfo, 1270 "sector-size", "%lu", §or_size, 1271 NULL); 1272 if (err) { 1273 xenbus_dev_fatal(dev, err, 1274 "reading backend fields at %s", 1275 xenbus_get_otherend_path(dev)); 1276 return; 1277 } 1278 if ((sectors == 0) || (sector_size == 0)) { 1279 xenbus_dev_fatal(dev, 0, 1280 "invalid parameters from %s:" 1281 " sectors = %lu, sector_size = %lu", 1282 xenbus_get_otherend_path(dev), 1283 sectors, sector_size); 1284 return; 1285 } 1286 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev), 1287 "physical-sector-size", "%lu", &phys_sector_size, 1288 NULL); 1289 if (err || phys_sector_size <= sector_size) 1290 phys_sector_size = 0; 1291 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev), 1292 "feature-barrier", "%d", &feature_barrier, 1293 NULL); 1294 if (err == 0 && feature_barrier != 0) 1295 sc->xbd_flags |= XBDF_BARRIER; 1296 1297 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev), 1298 "feature-flush-cache", "%d", &feature_flush, 1299 NULL); 1300 if (err == 0 && feature_flush != 0) 1301 sc->xbd_flags |= XBDF_FLUSH; 1302 1303 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev), 1304 "feature-max-indirect-segments", "%" PRIu32, 1305 &sc->xbd_max_request_segments, NULL); 1306 if ((err != 0) || (xbd_enable_indirect == 0)) 1307 sc->xbd_max_request_segments = 0; 1308 if (sc->xbd_max_request_segments > XBD_MAX_INDIRECT_SEGMENTS) 1309 sc->xbd_max_request_segments = XBD_MAX_INDIRECT_SEGMENTS; 1310 if (sc->xbd_max_request_segments > XBD_SIZE_TO_SEGS(MAXPHYS)) 1311 sc->xbd_max_request_segments = XBD_SIZE_TO_SEGS(MAXPHYS); 1312 sc->xbd_max_request_indirectpages = 1313 XBD_INDIRECT_SEGS_TO_PAGES(sc->xbd_max_request_segments); 1314 if (sc->xbd_max_request_segments < BLKIF_MAX_SEGMENTS_PER_REQUEST) 1315 sc->xbd_max_request_segments = BLKIF_MAX_SEGMENTS_PER_REQUEST; 1316 sc->xbd_max_request_size = 1317 XBD_SEGS_TO_SIZE(sc->xbd_max_request_segments); 1318 1319 /* Allocate datastructures based on negotiated values. */ 1320 err = bus_dma_tag_create( 1321 bus_get_dma_tag(sc->xbd_dev), /* parent */ 1322 512, PAGE_SIZE, /* algnmnt, boundary */ 1323 BUS_SPACE_MAXADDR, /* lowaddr */ 1324 BUS_SPACE_MAXADDR, /* highaddr */ 1325 NULL, NULL, /* filter, filterarg */ 1326 sc->xbd_max_request_size, 1327 sc->xbd_max_request_segments, 1328 PAGE_SIZE, /* maxsegsize */ 1329 BUS_DMA_ALLOCNOW, /* flags */ 1330 busdma_lock_mutex, /* lockfunc */ 1331 &sc->xbd_io_lock, /* lockarg */ 1332 &sc->xbd_io_dmat); 1333 if (err != 0) { 1334 xenbus_dev_fatal(sc->xbd_dev, err, 1335 "Cannot allocate parent DMA tag\n"); 1336 return; 1337 } 1338 1339 /* Per-transaction data allocation. */ 1340 sc->xbd_shadow = malloc(sizeof(*sc->xbd_shadow) * sc->xbd_max_requests, 1341 M_XENBLOCKFRONT, M_NOWAIT|M_ZERO); 1342 if (sc->xbd_shadow == NULL) { 1343 bus_dma_tag_destroy(sc->xbd_io_dmat); 1344 xenbus_dev_fatal(sc->xbd_dev, ENOMEM, 1345 "Cannot allocate request structures\n"); 1346 return; 1347 } 1348 1349 for (i = 0; i < sc->xbd_max_requests; i++) { 1350 struct xbd_command *cm; 1351 void * indirectpages; 1352 1353 cm = &sc->xbd_shadow[i]; 1354 cm->cm_sg_refs = malloc( 1355 sizeof(grant_ref_t) * sc->xbd_max_request_segments, 1356 M_XENBLOCKFRONT, M_NOWAIT); 1357 if (cm->cm_sg_refs == NULL) 1358 break; 1359 cm->cm_id = i; 1360 cm->cm_flags = XBDCF_INITIALIZER; 1361 cm->cm_sc = sc; 1362 if (bus_dmamap_create(sc->xbd_io_dmat, 0, &cm->cm_map) != 0) 1363 break; 1364 if (sc->xbd_max_request_indirectpages > 0) { 1365 indirectpages = contigmalloc( 1366 PAGE_SIZE * sc->xbd_max_request_indirectpages, 1367 M_XENBLOCKFRONT, M_ZERO | M_NOWAIT, 0, ~0, 1368 PAGE_SIZE, 0); 1369 if (indirectpages == NULL) 1370 sc->xbd_max_request_indirectpages = 0; 1371 } else { 1372 indirectpages = NULL; 1373 } 1374 for (j = 0; j < sc->xbd_max_request_indirectpages; j++) { 1375 if (gnttab_grant_foreign_access( 1376 xenbus_get_otherend_id(sc->xbd_dev), 1377 (vtophys(indirectpages) >> PAGE_SHIFT) + j, 1378 1 /* grant read-only access */, 1379 &cm->cm_indirectionrefs[j])) 1380 break; 1381 } 1382 if (j < sc->xbd_max_request_indirectpages) { 1383 contigfree(indirectpages, 1384 PAGE_SIZE * sc->xbd_max_request_indirectpages, 1385 M_XENBLOCKFRONT); 1386 break; 1387 } 1388 cm->cm_indirectionpages = indirectpages; 1389 xbd_free_command(cm); 1390 } 1391 1392 if (sc->xbd_disk == NULL) { 1393 device_printf(dev, "%juMB <%s> at %s", 1394 (uintmax_t) sectors / (1048576 / sector_size), 1395 device_get_desc(dev), 1396 xenbus_get_node(dev)); 1397 bus_print_child_footer(device_get_parent(dev), dev); 1398 1399 xbd_instance_create(sc, sectors, sc->xbd_vdevice, binfo, 1400 sector_size, phys_sector_size); 1401 } 1402 1403 (void)xenbus_set_state(dev, XenbusStateConnected); 1404 1405 /* Kick pending requests. */ 1406 mtx_lock(&sc->xbd_io_lock); 1407 sc->xbd_state = XBD_STATE_CONNECTED; 1408 xbd_startio(sc); 1409 sc->xbd_flags |= XBDF_READY; 1410 mtx_unlock(&sc->xbd_io_lock); 1411 } 1412 1413 /** 1414 * Handle the change of state of the backend to Closing. We must delete our 1415 * device-layer structures now, to ensure that writes are flushed through to 1416 * the backend. Once this is done, we can switch to Closed in 1417 * acknowledgement. 1418 */ 1419 static void 1420 xbd_closing(device_t dev) 1421 { 1422 struct xbd_softc *sc = device_get_softc(dev); 1423 1424 xenbus_set_state(dev, XenbusStateClosing); 1425 1426 DPRINTK("xbd_closing: %s removed\n", xenbus_get_node(dev)); 1427 1428 if (sc->xbd_disk != NULL) { 1429 disk_destroy(sc->xbd_disk); 1430 sc->xbd_disk = NULL; 1431 } 1432 1433 xenbus_set_state(dev, XenbusStateClosed); 1434 } 1435 1436 /*---------------------------- NewBus Entrypoints ----------------------------*/ 1437 static int 1438 xbd_probe(device_t dev) 1439 { 1440 if (strcmp(xenbus_get_type(dev), "vbd") != 0) 1441 return (ENXIO); 1442 1443 if (xen_hvm_domain() && xen_disable_pv_disks != 0) 1444 return (ENXIO); 1445 1446 if (xen_hvm_domain()) { 1447 int error; 1448 char *type; 1449 1450 /* 1451 * When running in an HVM domain, IDE disk emulation is 1452 * disabled early in boot so that native drivers will 1453 * not see emulated hardware. However, CDROM device 1454 * emulation cannot be disabled. 1455 * 1456 * Through use of FreeBSD's vm_guest and xen_hvm_domain() 1457 * APIs, we could modify the native CDROM driver to fail its 1458 * probe when running under Xen. Unfortunatlely, the PV 1459 * CDROM support in XenServer (up through at least version 1460 * 6.2) isn't functional, so we instead rely on the emulated 1461 * CDROM instance, and fail to attach the PV one here in 1462 * the blkfront driver. 1463 */ 1464 error = xs_read(XST_NIL, xenbus_get_node(dev), 1465 "device-type", NULL, (void **) &type); 1466 if (error) 1467 return (ENXIO); 1468 1469 if (strncmp(type, "cdrom", 5) == 0) { 1470 free(type, M_XENSTORE); 1471 return (ENXIO); 1472 } 1473 free(type, M_XENSTORE); 1474 } 1475 1476 device_set_desc(dev, "Virtual Block Device"); 1477 device_quiet(dev); 1478 return (0); 1479 } 1480 1481 /* 1482 * Setup supplies the backend dir, virtual device. We place an event 1483 * channel and shared frame entries. We watch backend to wait if it's 1484 * ok. 1485 */ 1486 static int 1487 xbd_attach(device_t dev) 1488 { 1489 struct xbd_softc *sc; 1490 const char *name; 1491 uint32_t vdevice; 1492 int error; 1493 int i; 1494 int unit; 1495 1496 /* FIXME: Use dynamic device id if this is not set. */ 1497 error = xs_scanf(XST_NIL, xenbus_get_node(dev), 1498 "virtual-device", NULL, "%" PRIu32, &vdevice); 1499 if (error) 1500 error = xs_scanf(XST_NIL, xenbus_get_node(dev), 1501 "virtual-device-ext", NULL, "%" PRIu32, &vdevice); 1502 if (error) { 1503 xenbus_dev_fatal(dev, error, "reading virtual-device"); 1504 device_printf(dev, "Couldn't determine virtual device.\n"); 1505 return (error); 1506 } 1507 1508 xbd_vdevice_to_unit(vdevice, &unit, &name); 1509 if (!strcmp(name, "xbd")) 1510 device_set_unit(dev, unit); 1511 1512 sc = device_get_softc(dev); 1513 mtx_init(&sc->xbd_io_lock, "blkfront i/o lock", NULL, MTX_DEF); 1514 xbd_initqs(sc); 1515 for (i = 0; i < XBD_MAX_RING_PAGES; i++) 1516 sc->xbd_ring_ref[i] = GRANT_REF_INVALID; 1517 1518 sc->xbd_dev = dev; 1519 sc->xbd_vdevice = vdevice; 1520 sc->xbd_state = XBD_STATE_DISCONNECTED; 1521 1522 xbd_setup_sysctl(sc); 1523 1524 /* Wait for backend device to publish its protocol capabilities. */ 1525 xenbus_set_state(dev, XenbusStateInitialising); 1526 1527 return (0); 1528 } 1529 1530 static int 1531 xbd_detach(device_t dev) 1532 { 1533 struct xbd_softc *sc = device_get_softc(dev); 1534 1535 DPRINTK("%s: %s removed\n", __func__, xenbus_get_node(dev)); 1536 1537 xbd_free(sc); 1538 mtx_destroy(&sc->xbd_io_lock); 1539 1540 return 0; 1541 } 1542 1543 static int 1544 xbd_suspend(device_t dev) 1545 { 1546 struct xbd_softc *sc = device_get_softc(dev); 1547 int retval; 1548 int saved_state; 1549 1550 /* Prevent new requests being issued until we fix things up. */ 1551 mtx_lock(&sc->xbd_io_lock); 1552 saved_state = sc->xbd_state; 1553 sc->xbd_state = XBD_STATE_SUSPENDED; 1554 1555 /* Wait for outstanding I/O to drain. */ 1556 retval = 0; 1557 while (xbd_queue_length(sc, XBD_Q_BUSY) != 0) { 1558 if (msleep(&sc->xbd_cm_q[XBD_Q_BUSY], &sc->xbd_io_lock, 1559 PRIBIO, "blkf_susp", 30 * hz) == EWOULDBLOCK) { 1560 retval = EBUSY; 1561 break; 1562 } 1563 } 1564 mtx_unlock(&sc->xbd_io_lock); 1565 1566 if (retval != 0) 1567 sc->xbd_state = saved_state; 1568 1569 return (retval); 1570 } 1571 1572 static int 1573 xbd_resume(device_t dev) 1574 { 1575 struct xbd_softc *sc = device_get_softc(dev); 1576 1577 if (xen_suspend_cancelled) { 1578 sc->xbd_state = XBD_STATE_CONNECTED; 1579 return (0); 1580 } 1581 1582 DPRINTK("xbd_resume: %s\n", xenbus_get_node(dev)); 1583 1584 xbd_free(sc); 1585 xbd_initialize(sc); 1586 return (0); 1587 } 1588 1589 /** 1590 * Callback received when the backend's state changes. 1591 */ 1592 static void 1593 xbd_backend_changed(device_t dev, XenbusState backend_state) 1594 { 1595 struct xbd_softc *sc = device_get_softc(dev); 1596 1597 DPRINTK("backend_state=%d\n", backend_state); 1598 1599 switch (backend_state) { 1600 case XenbusStateUnknown: 1601 case XenbusStateInitialising: 1602 case XenbusStateReconfigured: 1603 case XenbusStateReconfiguring: 1604 case XenbusStateClosed: 1605 break; 1606 1607 case XenbusStateInitWait: 1608 case XenbusStateInitialised: 1609 xbd_initialize(sc); 1610 break; 1611 1612 case XenbusStateConnected: 1613 xbd_initialize(sc); 1614 xbd_connect(sc); 1615 break; 1616 1617 case XenbusStateClosing: 1618 if (sc->xbd_users > 0) { 1619 device_printf(dev, "detaching with pending users\n"); 1620 KASSERT(sc->xbd_disk != NULL, 1621 ("NULL disk with pending users\n")); 1622 disk_gone(sc->xbd_disk); 1623 } else { 1624 xbd_closing(dev); 1625 } 1626 break; 1627 } 1628 } 1629 1630 /*---------------------------- NewBus Registration ---------------------------*/ 1631 static device_method_t xbd_methods[] = { 1632 /* Device interface */ 1633 DEVMETHOD(device_probe, xbd_probe), 1634 DEVMETHOD(device_attach, xbd_attach), 1635 DEVMETHOD(device_detach, xbd_detach), 1636 DEVMETHOD(device_shutdown, bus_generic_shutdown), 1637 DEVMETHOD(device_suspend, xbd_suspend), 1638 DEVMETHOD(device_resume, xbd_resume), 1639 1640 /* Xenbus interface */ 1641 DEVMETHOD(xenbus_otherend_changed, xbd_backend_changed), 1642 1643 { 0, 0 } 1644 }; 1645 1646 static driver_t xbd_driver = { 1647 "xbd", 1648 xbd_methods, 1649 sizeof(struct xbd_softc), 1650 }; 1651 devclass_t xbd_devclass; 1652 1653 DRIVER_MODULE(xbd, xenbusb_front, xbd_driver, xbd_devclass, 0, 0); 1654