1 /****************************************************************************** 2 * Client-facing interface for the Xenbus driver. In other words, the 3 * interface between the Xenbus and the device-specific code, be it the 4 * frontend or the backend of that driver. 5 * 6 * Copyright (C) 2005 XenSource Ltd 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public License version 2 10 * as published by the Free Software Foundation; or, when distributed 11 * separately from the Linux kernel or incorporated into other 12 * software packages, subject to the following license: 13 * 14 * Permission is hereby granted, free of charge, to any person obtaining a copy 15 * of this source file (the "Software"), to deal in the Software without 16 * restriction, including without limitation the rights to use, copy, modify, 17 * merge, publish, distribute, sublicense, and/or sell copies of the Software, 18 * and to permit persons to whom the Software is furnished to do so, subject to 19 * the following conditions: 20 * 21 * The above copyright notice and this permission notice shall be included in 22 * all copies or substantial portions of the Software. 23 * 24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 25 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 26 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 27 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 28 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 29 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 30 * IN THE SOFTWARE. 31 */ 32 33 #include <linux/mm.h> 34 #include <linux/slab.h> 35 #include <linux/types.h> 36 #include <linux/spinlock.h> 37 #include <linux/vmalloc.h> 38 #include <linux/export.h> 39 #include <asm/xen/hypervisor.h> 40 #include <xen/page.h> 41 #include <xen/interface/xen.h> 42 #include <xen/interface/event_channel.h> 43 #include <xen/balloon.h> 44 #include <xen/events.h> 45 #include <xen/grant_table.h> 46 #include <xen/xenbus.h> 47 #include <xen/xen.h> 48 #include <xen/features.h> 49 50 #include "xenbus.h" 51 52 #define XENBUS_PAGES(_grants) (DIV_ROUND_UP(_grants, XEN_PFN_PER_PAGE)) 53 54 #define XENBUS_MAX_RING_PAGES (XENBUS_PAGES(XENBUS_MAX_RING_GRANTS)) 55 56 struct xenbus_map_node { 57 struct list_head next; 58 union { 59 struct { 60 struct vm_struct *area; 61 } pv; 62 struct { 63 struct page *pages[XENBUS_MAX_RING_PAGES]; 64 unsigned long addrs[XENBUS_MAX_RING_GRANTS]; 65 void *addr; 66 } hvm; 67 }; 68 grant_handle_t handles[XENBUS_MAX_RING_GRANTS]; 69 unsigned int nr_handles; 70 }; 71 72 struct map_ring_valloc { 73 struct xenbus_map_node *node; 74 75 /* Why do we need two arrays? See comment of __xenbus_map_ring */ 76 unsigned long addrs[XENBUS_MAX_RING_GRANTS]; 77 phys_addr_t phys_addrs[XENBUS_MAX_RING_GRANTS]; 78 79 struct gnttab_map_grant_ref map[XENBUS_MAX_RING_GRANTS]; 80 struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS]; 81 82 unsigned int idx; 83 }; 84 85 static DEFINE_SPINLOCK(xenbus_valloc_lock); 86 static LIST_HEAD(xenbus_valloc_pages); 87 88 struct xenbus_ring_ops { 89 int (*map)(struct xenbus_device *dev, struct map_ring_valloc *info, 90 grant_ref_t *gnt_refs, unsigned int nr_grefs, 91 void **vaddr); 92 int (*unmap)(struct xenbus_device *dev, void *vaddr); 93 }; 94 95 static const struct xenbus_ring_ops *ring_ops __read_mostly; 96 97 const char *xenbus_strstate(enum xenbus_state state) 98 { 99 static const char *const name[] = { 100 [ XenbusStateUnknown ] = "Unknown", 101 [ XenbusStateInitialising ] = "Initialising", 102 [ XenbusStateInitWait ] = "InitWait", 103 [ XenbusStateInitialised ] = "Initialised", 104 [ XenbusStateConnected ] = "Connected", 105 [ XenbusStateClosing ] = "Closing", 106 [ XenbusStateClosed ] = "Closed", 107 [XenbusStateReconfiguring] = "Reconfiguring", 108 [XenbusStateReconfigured] = "Reconfigured", 109 }; 110 return (state < ARRAY_SIZE(name)) ? name[state] : "INVALID"; 111 } 112 EXPORT_SYMBOL_GPL(xenbus_strstate); 113 114 /** 115 * xenbus_watch_path - register a watch 116 * @dev: xenbus device 117 * @path: path to watch 118 * @watch: watch to register 119 * @callback: callback to register 120 * 121 * Register a @watch on the given path, using the given xenbus_watch structure 122 * for storage, and the given @callback function as the callback. Return 0 on 123 * success, or -errno on error. On success, the given @path will be saved as 124 * @watch->node, and remains the caller's to free. On error, @watch->node will 125 * be NULL, the device will switch to %XenbusStateClosing, and the error will 126 * be saved in the store. 127 */ 128 int xenbus_watch_path(struct xenbus_device *dev, const char *path, 129 struct xenbus_watch *watch, 130 bool (*will_handle)(struct xenbus_watch *, 131 const char *, const char *), 132 void (*callback)(struct xenbus_watch *, 133 const char *, const char *)) 134 { 135 int err; 136 137 watch->node = path; 138 watch->will_handle = will_handle; 139 watch->callback = callback; 140 141 err = register_xenbus_watch(watch); 142 143 if (err) { 144 watch->node = NULL; 145 watch->will_handle = NULL; 146 watch->callback = NULL; 147 xenbus_dev_fatal(dev, err, "adding watch on %s", path); 148 } 149 150 return err; 151 } 152 EXPORT_SYMBOL_GPL(xenbus_watch_path); 153 154 155 /** 156 * xenbus_watch_pathfmt - register a watch on a sprintf-formatted path 157 * @dev: xenbus device 158 * @watch: watch to register 159 * @callback: callback to register 160 * @pathfmt: format of path to watch 161 * 162 * Register a watch on the given @path, using the given xenbus_watch 163 * structure for storage, and the given @callback function as the callback. 164 * Return 0 on success, or -errno on error. On success, the watched path 165 * (@path/@path2) will be saved as @watch->node, and becomes the caller's to 166 * kfree(). On error, watch->node will be NULL, so the caller has nothing to 167 * free, the device will switch to %XenbusStateClosing, and the error will be 168 * saved in the store. 169 */ 170 int xenbus_watch_pathfmt(struct xenbus_device *dev, 171 struct xenbus_watch *watch, 172 bool (*will_handle)(struct xenbus_watch *, 173 const char *, const char *), 174 void (*callback)(struct xenbus_watch *, 175 const char *, const char *), 176 const char *pathfmt, ...) 177 { 178 int err; 179 va_list ap; 180 char *path; 181 182 va_start(ap, pathfmt); 183 path = kvasprintf(GFP_NOIO | __GFP_HIGH, pathfmt, ap); 184 va_end(ap); 185 186 if (!path) { 187 xenbus_dev_fatal(dev, -ENOMEM, "allocating path for watch"); 188 return -ENOMEM; 189 } 190 err = xenbus_watch_path(dev, path, watch, will_handle, callback); 191 192 if (err) 193 kfree(path); 194 return err; 195 } 196 EXPORT_SYMBOL_GPL(xenbus_watch_pathfmt); 197 198 static void xenbus_switch_fatal(struct xenbus_device *, int, int, 199 const char *, ...); 200 201 static int 202 __xenbus_switch_state(struct xenbus_device *dev, 203 enum xenbus_state state, int depth) 204 { 205 /* We check whether the state is currently set to the given value, and 206 if not, then the state is set. We don't want to unconditionally 207 write the given state, because we don't want to fire watches 208 unnecessarily. Furthermore, if the node has gone, we don't write 209 to it, as the device will be tearing down, and we don't want to 210 resurrect that directory. 211 212 Note that, because of this cached value of our state, this 213 function will not take a caller's Xenstore transaction 214 (something it was trying to in the past) because dev->state 215 would not get reset if the transaction was aborted. 216 */ 217 218 struct xenbus_transaction xbt; 219 int current_state; 220 int err, abort; 221 222 if (state == dev->state) 223 return 0; 224 225 again: 226 abort = 1; 227 228 err = xenbus_transaction_start(&xbt); 229 if (err) { 230 xenbus_switch_fatal(dev, depth, err, "starting transaction"); 231 return 0; 232 } 233 234 err = xenbus_scanf(xbt, dev->nodename, "state", "%d", ¤t_state); 235 if (err != 1) 236 goto abort; 237 238 err = xenbus_printf(xbt, dev->nodename, "state", "%d", state); 239 if (err) { 240 xenbus_switch_fatal(dev, depth, err, "writing new state"); 241 goto abort; 242 } 243 244 abort = 0; 245 abort: 246 err = xenbus_transaction_end(xbt, abort); 247 if (err) { 248 if (err == -EAGAIN && !abort) 249 goto again; 250 xenbus_switch_fatal(dev, depth, err, "ending transaction"); 251 } else 252 dev->state = state; 253 254 return 0; 255 } 256 257 /** 258 * xenbus_switch_state 259 * @dev: xenbus device 260 * @state: new state 261 * 262 * Advertise in the store a change of the given driver to the given new_state. 263 * Return 0 on success, or -errno on error. On error, the device will switch 264 * to XenbusStateClosing, and the error will be saved in the store. 265 */ 266 int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state state) 267 { 268 return __xenbus_switch_state(dev, state, 0); 269 } 270 271 EXPORT_SYMBOL_GPL(xenbus_switch_state); 272 273 int xenbus_frontend_closed(struct xenbus_device *dev) 274 { 275 xenbus_switch_state(dev, XenbusStateClosed); 276 complete(&dev->down); 277 return 0; 278 } 279 EXPORT_SYMBOL_GPL(xenbus_frontend_closed); 280 281 static void xenbus_va_dev_error(struct xenbus_device *dev, int err, 282 const char *fmt, va_list ap) 283 { 284 unsigned int len; 285 char *printf_buffer; 286 char *path_buffer; 287 288 #define PRINTF_BUFFER_SIZE 4096 289 290 printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_KERNEL); 291 if (!printf_buffer) 292 return; 293 294 len = sprintf(printf_buffer, "%i ", -err); 295 vsnprintf(printf_buffer + len, PRINTF_BUFFER_SIZE - len, fmt, ap); 296 297 dev_err(&dev->dev, "%s\n", printf_buffer); 298 299 path_buffer = kasprintf(GFP_KERNEL, "error/%s", dev->nodename); 300 if (path_buffer) 301 xenbus_write(XBT_NIL, path_buffer, "error", printf_buffer); 302 303 kfree(printf_buffer); 304 kfree(path_buffer); 305 } 306 307 /** 308 * xenbus_dev_error 309 * @dev: xenbus device 310 * @err: error to report 311 * @fmt: error message format 312 * 313 * Report the given negative errno into the store, along with the given 314 * formatted message. 315 */ 316 void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...) 317 { 318 va_list ap; 319 320 va_start(ap, fmt); 321 xenbus_va_dev_error(dev, err, fmt, ap); 322 va_end(ap); 323 } 324 EXPORT_SYMBOL_GPL(xenbus_dev_error); 325 326 /** 327 * xenbus_dev_fatal 328 * @dev: xenbus device 329 * @err: error to report 330 * @fmt: error message format 331 * 332 * Equivalent to xenbus_dev_error(dev, err, fmt, args), followed by 333 * xenbus_switch_state(dev, XenbusStateClosing) to schedule an orderly 334 * closedown of this driver and its peer. 335 */ 336 337 void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...) 338 { 339 va_list ap; 340 341 va_start(ap, fmt); 342 xenbus_va_dev_error(dev, err, fmt, ap); 343 va_end(ap); 344 345 xenbus_switch_state(dev, XenbusStateClosing); 346 } 347 EXPORT_SYMBOL_GPL(xenbus_dev_fatal); 348 349 /** 350 * Equivalent to xenbus_dev_fatal(dev, err, fmt, args), but helps 351 * avoiding recursion within xenbus_switch_state. 352 */ 353 static void xenbus_switch_fatal(struct xenbus_device *dev, int depth, int err, 354 const char *fmt, ...) 355 { 356 va_list ap; 357 358 va_start(ap, fmt); 359 xenbus_va_dev_error(dev, err, fmt, ap); 360 va_end(ap); 361 362 if (!depth) 363 __xenbus_switch_state(dev, XenbusStateClosing, 1); 364 } 365 366 /** 367 * xenbus_grant_ring 368 * @dev: xenbus device 369 * @vaddr: starting virtual address of the ring 370 * @nr_pages: number of pages to be granted 371 * @grefs: grant reference array to be filled in 372 * 373 * Grant access to the given @vaddr to the peer of the given device. 374 * Then fill in @grefs with grant references. Return 0 on success, or 375 * -errno on error. On error, the device will switch to 376 * XenbusStateClosing, and the error will be saved in the store. 377 */ 378 int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr, 379 unsigned int nr_pages, grant_ref_t *grefs) 380 { 381 int err; 382 unsigned int i; 383 grant_ref_t gref_head; 384 385 err = gnttab_alloc_grant_references(nr_pages, &gref_head); 386 if (err) { 387 xenbus_dev_fatal(dev, err, "granting access to ring page"); 388 return err; 389 } 390 391 for (i = 0; i < nr_pages; i++) { 392 unsigned long gfn; 393 394 if (is_vmalloc_addr(vaddr)) 395 gfn = pfn_to_gfn(vmalloc_to_pfn(vaddr)); 396 else 397 gfn = virt_to_gfn(vaddr); 398 399 grefs[i] = gnttab_claim_grant_reference(&gref_head); 400 gnttab_grant_foreign_access_ref(grefs[i], dev->otherend_id, 401 gfn, 0); 402 403 vaddr = vaddr + XEN_PAGE_SIZE; 404 } 405 406 return 0; 407 } 408 EXPORT_SYMBOL_GPL(xenbus_grant_ring); 409 410 411 /** 412 * Allocate an event channel for the given xenbus_device, assigning the newly 413 * created local port to *port. Return 0 on success, or -errno on error. On 414 * error, the device will switch to XenbusStateClosing, and the error will be 415 * saved in the store. 416 */ 417 int xenbus_alloc_evtchn(struct xenbus_device *dev, evtchn_port_t *port) 418 { 419 struct evtchn_alloc_unbound alloc_unbound; 420 int err; 421 422 alloc_unbound.dom = DOMID_SELF; 423 alloc_unbound.remote_dom = dev->otherend_id; 424 425 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, 426 &alloc_unbound); 427 if (err) 428 xenbus_dev_fatal(dev, err, "allocating event channel"); 429 else 430 *port = alloc_unbound.port; 431 432 return err; 433 } 434 EXPORT_SYMBOL_GPL(xenbus_alloc_evtchn); 435 436 437 /** 438 * Free an existing event channel. Returns 0 on success or -errno on error. 439 */ 440 int xenbus_free_evtchn(struct xenbus_device *dev, evtchn_port_t port) 441 { 442 struct evtchn_close close; 443 int err; 444 445 close.port = port; 446 447 err = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close); 448 if (err) 449 xenbus_dev_error(dev, err, "freeing event channel %u", port); 450 451 return err; 452 } 453 EXPORT_SYMBOL_GPL(xenbus_free_evtchn); 454 455 456 /** 457 * xenbus_map_ring_valloc 458 * @dev: xenbus device 459 * @gnt_refs: grant reference array 460 * @nr_grefs: number of grant references 461 * @vaddr: pointer to address to be filled out by mapping 462 * 463 * Map @nr_grefs pages of memory into this domain from another 464 * domain's grant table. xenbus_map_ring_valloc allocates @nr_grefs 465 * pages of virtual address space, maps the pages to that address, and 466 * sets *vaddr to that address. Returns 0 on success, and -errno on 467 * error. If an error is returned, device will switch to 468 * XenbusStateClosing and the error message will be saved in XenStore. 469 */ 470 int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs, 471 unsigned int nr_grefs, void **vaddr) 472 { 473 int err; 474 struct map_ring_valloc *info; 475 476 *vaddr = NULL; 477 478 if (nr_grefs > XENBUS_MAX_RING_GRANTS) 479 return -EINVAL; 480 481 info = kzalloc(sizeof(*info), GFP_KERNEL); 482 if (!info) 483 return -ENOMEM; 484 485 info->node = kzalloc(sizeof(*info->node), GFP_KERNEL); 486 if (!info->node) 487 err = -ENOMEM; 488 else 489 err = ring_ops->map(dev, info, gnt_refs, nr_grefs, vaddr); 490 491 kfree(info->node); 492 kfree(info); 493 return err; 494 } 495 EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc); 496 497 /* N.B. sizeof(phys_addr_t) doesn't always equal to sizeof(unsigned 498 * long), e.g. 32-on-64. Caller is responsible for preparing the 499 * right array to feed into this function */ 500 static int __xenbus_map_ring(struct xenbus_device *dev, 501 grant_ref_t *gnt_refs, 502 unsigned int nr_grefs, 503 grant_handle_t *handles, 504 struct map_ring_valloc *info, 505 unsigned int flags, 506 bool *leaked) 507 { 508 int i, j; 509 510 if (nr_grefs > XENBUS_MAX_RING_GRANTS) 511 return -EINVAL; 512 513 for (i = 0; i < nr_grefs; i++) { 514 gnttab_set_map_op(&info->map[i], info->phys_addrs[i], flags, 515 gnt_refs[i], dev->otherend_id); 516 handles[i] = INVALID_GRANT_HANDLE; 517 } 518 519 gnttab_batch_map(info->map, i); 520 521 for (i = 0; i < nr_grefs; i++) { 522 if (info->map[i].status != GNTST_okay) { 523 xenbus_dev_fatal(dev, info->map[i].status, 524 "mapping in shared page %d from domain %d", 525 gnt_refs[i], dev->otherend_id); 526 goto fail; 527 } else 528 handles[i] = info->map[i].handle; 529 } 530 531 return 0; 532 533 fail: 534 for (i = j = 0; i < nr_grefs; i++) { 535 if (handles[i] != INVALID_GRANT_HANDLE) { 536 gnttab_set_unmap_op(&info->unmap[j], 537 info->phys_addrs[i], 538 GNTMAP_host_map, handles[i]); 539 j++; 540 } 541 } 542 543 BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, info->unmap, j)); 544 545 *leaked = false; 546 for (i = 0; i < j; i++) { 547 if (info->unmap[i].status != GNTST_okay) { 548 *leaked = true; 549 break; 550 } 551 } 552 553 return -ENOENT; 554 } 555 556 /** 557 * xenbus_unmap_ring 558 * @dev: xenbus device 559 * @handles: grant handle array 560 * @nr_handles: number of handles in the array 561 * @vaddrs: addresses to unmap 562 * 563 * Unmap memory in this domain that was imported from another domain. 564 * Returns 0 on success and returns GNTST_* on error 565 * (see xen/include/interface/grant_table.h). 566 */ 567 static int xenbus_unmap_ring(struct xenbus_device *dev, grant_handle_t *handles, 568 unsigned int nr_handles, unsigned long *vaddrs) 569 { 570 struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS]; 571 int i; 572 int err; 573 574 if (nr_handles > XENBUS_MAX_RING_GRANTS) 575 return -EINVAL; 576 577 for (i = 0; i < nr_handles; i++) 578 gnttab_set_unmap_op(&unmap[i], vaddrs[i], 579 GNTMAP_host_map, handles[i]); 580 581 BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i)); 582 583 err = GNTST_okay; 584 for (i = 0; i < nr_handles; i++) { 585 if (unmap[i].status != GNTST_okay) { 586 xenbus_dev_error(dev, unmap[i].status, 587 "unmapping page at handle %d error %d", 588 handles[i], unmap[i].status); 589 err = unmap[i].status; 590 break; 591 } 592 } 593 594 return err; 595 } 596 597 static void xenbus_map_ring_setup_grant_hvm(unsigned long gfn, 598 unsigned int goffset, 599 unsigned int len, 600 void *data) 601 { 602 struct map_ring_valloc *info = data; 603 unsigned long vaddr = (unsigned long)gfn_to_virt(gfn); 604 605 info->phys_addrs[info->idx] = vaddr; 606 info->addrs[info->idx] = vaddr; 607 608 info->idx++; 609 } 610 611 static int xenbus_map_ring_hvm(struct xenbus_device *dev, 612 struct map_ring_valloc *info, 613 grant_ref_t *gnt_ref, 614 unsigned int nr_grefs, 615 void **vaddr) 616 { 617 struct xenbus_map_node *node = info->node; 618 int err; 619 void *addr; 620 bool leaked = false; 621 unsigned int nr_pages = XENBUS_PAGES(nr_grefs); 622 623 err = xen_alloc_unpopulated_pages(nr_pages, node->hvm.pages); 624 if (err) 625 goto out_err; 626 627 gnttab_foreach_grant(node->hvm.pages, nr_grefs, 628 xenbus_map_ring_setup_grant_hvm, 629 info); 630 631 err = __xenbus_map_ring(dev, gnt_ref, nr_grefs, node->handles, 632 info, GNTMAP_host_map, &leaked); 633 node->nr_handles = nr_grefs; 634 635 if (err) 636 goto out_free_ballooned_pages; 637 638 addr = vmap(node->hvm.pages, nr_pages, VM_MAP | VM_IOREMAP, 639 PAGE_KERNEL); 640 if (!addr) { 641 err = -ENOMEM; 642 goto out_xenbus_unmap_ring; 643 } 644 645 node->hvm.addr = addr; 646 647 spin_lock(&xenbus_valloc_lock); 648 list_add(&node->next, &xenbus_valloc_pages); 649 spin_unlock(&xenbus_valloc_lock); 650 651 *vaddr = addr; 652 info->node = NULL; 653 654 return 0; 655 656 out_xenbus_unmap_ring: 657 if (!leaked) 658 xenbus_unmap_ring(dev, node->handles, nr_grefs, info->addrs); 659 else 660 pr_alert("leaking %p size %u page(s)", 661 addr, nr_pages); 662 out_free_ballooned_pages: 663 if (!leaked) 664 xen_free_unpopulated_pages(nr_pages, node->hvm.pages); 665 out_err: 666 return err; 667 } 668 669 /** 670 * xenbus_unmap_ring_vfree 671 * @dev: xenbus device 672 * @vaddr: addr to unmap 673 * 674 * Based on Rusty Russell's skeleton driver's unmap_page. 675 * Unmap a page of memory in this domain that was imported from another domain. 676 * Use xenbus_unmap_ring_vfree if you mapped in your memory with 677 * xenbus_map_ring_valloc (it will free the virtual address space). 678 * Returns 0 on success and returns GNTST_* on error 679 * (see xen/include/interface/grant_table.h). 680 */ 681 int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr) 682 { 683 return ring_ops->unmap(dev, vaddr); 684 } 685 EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree); 686 687 #ifdef CONFIG_XEN_PV 688 static int map_ring_apply(pte_t *pte, unsigned long addr, void *data) 689 { 690 struct map_ring_valloc *info = data; 691 692 info->phys_addrs[info->idx++] = arbitrary_virt_to_machine(pte).maddr; 693 return 0; 694 } 695 696 static int xenbus_map_ring_pv(struct xenbus_device *dev, 697 struct map_ring_valloc *info, 698 grant_ref_t *gnt_refs, 699 unsigned int nr_grefs, 700 void **vaddr) 701 { 702 struct xenbus_map_node *node = info->node; 703 struct vm_struct *area; 704 bool leaked = false; 705 int err = -ENOMEM; 706 707 area = get_vm_area(XEN_PAGE_SIZE * nr_grefs, VM_IOREMAP); 708 if (!area) 709 return -ENOMEM; 710 if (apply_to_page_range(&init_mm, (unsigned long)area->addr, 711 XEN_PAGE_SIZE * nr_grefs, map_ring_apply, info)) 712 goto failed; 713 err = __xenbus_map_ring(dev, gnt_refs, nr_grefs, node->handles, 714 info, GNTMAP_host_map | GNTMAP_contains_pte, 715 &leaked); 716 if (err) 717 goto failed; 718 719 node->nr_handles = nr_grefs; 720 node->pv.area = area; 721 722 spin_lock(&xenbus_valloc_lock); 723 list_add(&node->next, &xenbus_valloc_pages); 724 spin_unlock(&xenbus_valloc_lock); 725 726 *vaddr = area->addr; 727 info->node = NULL; 728 729 return 0; 730 731 failed: 732 if (!leaked) 733 free_vm_area(area); 734 else 735 pr_alert("leaking VM area %p size %u page(s)", area, nr_grefs); 736 737 return err; 738 } 739 740 static int xenbus_unmap_ring_pv(struct xenbus_device *dev, void *vaddr) 741 { 742 struct xenbus_map_node *node; 743 struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS]; 744 unsigned int level; 745 int i; 746 bool leaked = false; 747 int err; 748 749 spin_lock(&xenbus_valloc_lock); 750 list_for_each_entry(node, &xenbus_valloc_pages, next) { 751 if (node->pv.area->addr == vaddr) { 752 list_del(&node->next); 753 goto found; 754 } 755 } 756 node = NULL; 757 found: 758 spin_unlock(&xenbus_valloc_lock); 759 760 if (!node) { 761 xenbus_dev_error(dev, -ENOENT, 762 "can't find mapped virtual address %p", vaddr); 763 return GNTST_bad_virt_addr; 764 } 765 766 for (i = 0; i < node->nr_handles; i++) { 767 unsigned long addr; 768 769 memset(&unmap[i], 0, sizeof(unmap[i])); 770 addr = (unsigned long)vaddr + (XEN_PAGE_SIZE * i); 771 unmap[i].host_addr = arbitrary_virt_to_machine( 772 lookup_address(addr, &level)).maddr; 773 unmap[i].dev_bus_addr = 0; 774 unmap[i].handle = node->handles[i]; 775 } 776 777 BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i)); 778 779 err = GNTST_okay; 780 leaked = false; 781 for (i = 0; i < node->nr_handles; i++) { 782 if (unmap[i].status != GNTST_okay) { 783 leaked = true; 784 xenbus_dev_error(dev, unmap[i].status, 785 "unmapping page at handle %d error %d", 786 node->handles[i], unmap[i].status); 787 err = unmap[i].status; 788 break; 789 } 790 } 791 792 if (!leaked) 793 free_vm_area(node->pv.area); 794 else 795 pr_alert("leaking VM area %p size %u page(s)", 796 node->pv.area, node->nr_handles); 797 798 kfree(node); 799 return err; 800 } 801 802 static const struct xenbus_ring_ops ring_ops_pv = { 803 .map = xenbus_map_ring_pv, 804 .unmap = xenbus_unmap_ring_pv, 805 }; 806 #endif 807 808 struct unmap_ring_hvm 809 { 810 unsigned int idx; 811 unsigned long addrs[XENBUS_MAX_RING_GRANTS]; 812 }; 813 814 static void xenbus_unmap_ring_setup_grant_hvm(unsigned long gfn, 815 unsigned int goffset, 816 unsigned int len, 817 void *data) 818 { 819 struct unmap_ring_hvm *info = data; 820 821 info->addrs[info->idx] = (unsigned long)gfn_to_virt(gfn); 822 823 info->idx++; 824 } 825 826 static int xenbus_unmap_ring_hvm(struct xenbus_device *dev, void *vaddr) 827 { 828 int rv; 829 struct xenbus_map_node *node; 830 void *addr; 831 struct unmap_ring_hvm info = { 832 .idx = 0, 833 }; 834 unsigned int nr_pages; 835 836 spin_lock(&xenbus_valloc_lock); 837 list_for_each_entry(node, &xenbus_valloc_pages, next) { 838 addr = node->hvm.addr; 839 if (addr == vaddr) { 840 list_del(&node->next); 841 goto found; 842 } 843 } 844 node = addr = NULL; 845 found: 846 spin_unlock(&xenbus_valloc_lock); 847 848 if (!node) { 849 xenbus_dev_error(dev, -ENOENT, 850 "can't find mapped virtual address %p", vaddr); 851 return GNTST_bad_virt_addr; 852 } 853 854 nr_pages = XENBUS_PAGES(node->nr_handles); 855 856 gnttab_foreach_grant(node->hvm.pages, node->nr_handles, 857 xenbus_unmap_ring_setup_grant_hvm, 858 &info); 859 860 rv = xenbus_unmap_ring(dev, node->handles, node->nr_handles, 861 info.addrs); 862 if (!rv) { 863 vunmap(vaddr); 864 xen_free_unpopulated_pages(nr_pages, node->hvm.pages); 865 } 866 else 867 WARN(1, "Leaking %p, size %u page(s)\n", vaddr, nr_pages); 868 869 kfree(node); 870 return rv; 871 } 872 873 /** 874 * xenbus_read_driver_state 875 * @path: path for driver 876 * 877 * Return the state of the driver rooted at the given store path, or 878 * XenbusStateUnknown if no state can be read. 879 */ 880 enum xenbus_state xenbus_read_driver_state(const char *path) 881 { 882 enum xenbus_state result; 883 int err = xenbus_gather(XBT_NIL, path, "state", "%d", &result, NULL); 884 if (err) 885 result = XenbusStateUnknown; 886 887 return result; 888 } 889 EXPORT_SYMBOL_GPL(xenbus_read_driver_state); 890 891 static const struct xenbus_ring_ops ring_ops_hvm = { 892 .map = xenbus_map_ring_hvm, 893 .unmap = xenbus_unmap_ring_hvm, 894 }; 895 896 void __init xenbus_ring_ops_init(void) 897 { 898 #ifdef CONFIG_XEN_PV 899 if (!xen_feature(XENFEAT_auto_translated_physmap)) 900 ring_ops = &ring_ops_pv; 901 else 902 #endif 903 ring_ops = &ring_ops_hvm; 904 } 905