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