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