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