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 int i, j; 383 384 for (i = 0; i < nr_pages; i++) { 385 unsigned long gfn; 386 387 if (is_vmalloc_addr(vaddr)) 388 gfn = pfn_to_gfn(vmalloc_to_pfn(vaddr)); 389 else 390 gfn = virt_to_gfn(vaddr); 391 392 err = gnttab_grant_foreign_access(dev->otherend_id, gfn, 0); 393 if (err < 0) { 394 xenbus_dev_fatal(dev, err, 395 "granting access to ring page"); 396 goto fail; 397 } 398 grefs[i] = err; 399 400 vaddr = vaddr + XEN_PAGE_SIZE; 401 } 402 403 return 0; 404 405 fail: 406 for (j = 0; j < i; j++) 407 gnttab_end_foreign_access_ref(grefs[j], 0); 408 return err; 409 } 410 EXPORT_SYMBOL_GPL(xenbus_grant_ring); 411 412 413 /** 414 * Allocate an event channel for the given xenbus_device, assigning the newly 415 * created local port to *port. Return 0 on success, or -errno on error. On 416 * error, the device will switch to XenbusStateClosing, and the error will be 417 * saved in the store. 418 */ 419 int xenbus_alloc_evtchn(struct xenbus_device *dev, evtchn_port_t *port) 420 { 421 struct evtchn_alloc_unbound alloc_unbound; 422 int err; 423 424 alloc_unbound.dom = DOMID_SELF; 425 alloc_unbound.remote_dom = dev->otherend_id; 426 427 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, 428 &alloc_unbound); 429 if (err) 430 xenbus_dev_fatal(dev, err, "allocating event channel"); 431 else 432 *port = alloc_unbound.port; 433 434 return err; 435 } 436 EXPORT_SYMBOL_GPL(xenbus_alloc_evtchn); 437 438 439 /** 440 * Free an existing event channel. Returns 0 on success or -errno on error. 441 */ 442 int xenbus_free_evtchn(struct xenbus_device *dev, evtchn_port_t port) 443 { 444 struct evtchn_close close; 445 int err; 446 447 close.port = port; 448 449 err = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close); 450 if (err) 451 xenbus_dev_error(dev, err, "freeing event channel %u", port); 452 453 return err; 454 } 455 EXPORT_SYMBOL_GPL(xenbus_free_evtchn); 456 457 458 /** 459 * xenbus_map_ring_valloc 460 * @dev: xenbus device 461 * @gnt_refs: grant reference array 462 * @nr_grefs: number of grant references 463 * @vaddr: pointer to address to be filled out by mapping 464 * 465 * Map @nr_grefs pages of memory into this domain from another 466 * domain's grant table. xenbus_map_ring_valloc allocates @nr_grefs 467 * pages of virtual address space, maps the pages to that address, and 468 * sets *vaddr to that address. Returns 0 on success, and -errno on 469 * error. If an error is returned, device will switch to 470 * XenbusStateClosing and the error message will be saved in XenStore. 471 */ 472 int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs, 473 unsigned int nr_grefs, void **vaddr) 474 { 475 int err; 476 struct map_ring_valloc *info; 477 478 *vaddr = NULL; 479 480 if (nr_grefs > XENBUS_MAX_RING_GRANTS) 481 return -EINVAL; 482 483 info = kzalloc(sizeof(*info), GFP_KERNEL); 484 if (!info) 485 return -ENOMEM; 486 487 info->node = kzalloc(sizeof(*info->node), GFP_KERNEL); 488 if (!info->node) 489 err = -ENOMEM; 490 else 491 err = ring_ops->map(dev, info, gnt_refs, nr_grefs, vaddr); 492 493 kfree(info->node); 494 kfree(info); 495 return err; 496 } 497 EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc); 498 499 /* N.B. sizeof(phys_addr_t) doesn't always equal to sizeof(unsigned 500 * long), e.g. 32-on-64. Caller is responsible for preparing the 501 * right array to feed into this function */ 502 static int __xenbus_map_ring(struct xenbus_device *dev, 503 grant_ref_t *gnt_refs, 504 unsigned int nr_grefs, 505 grant_handle_t *handles, 506 struct map_ring_valloc *info, 507 unsigned int flags, 508 bool *leaked) 509 { 510 int i, j; 511 512 if (nr_grefs > XENBUS_MAX_RING_GRANTS) 513 return -EINVAL; 514 515 for (i = 0; i < nr_grefs; i++) { 516 gnttab_set_map_op(&info->map[i], info->phys_addrs[i], flags, 517 gnt_refs[i], dev->otherend_id); 518 handles[i] = INVALID_GRANT_HANDLE; 519 } 520 521 gnttab_batch_map(info->map, i); 522 523 for (i = 0; i < nr_grefs; i++) { 524 if (info->map[i].status != GNTST_okay) { 525 xenbus_dev_fatal(dev, info->map[i].status, 526 "mapping in shared page %d from domain %d", 527 gnt_refs[i], dev->otherend_id); 528 goto fail; 529 } else 530 handles[i] = info->map[i].handle; 531 } 532 533 return 0; 534 535 fail: 536 for (i = j = 0; i < nr_grefs; i++) { 537 if (handles[i] != INVALID_GRANT_HANDLE) { 538 gnttab_set_unmap_op(&info->unmap[j], 539 info->phys_addrs[i], 540 GNTMAP_host_map, handles[i]); 541 j++; 542 } 543 } 544 545 BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, info->unmap, j)); 546 547 *leaked = false; 548 for (i = 0; i < j; i++) { 549 if (info->unmap[i].status != GNTST_okay) { 550 *leaked = true; 551 break; 552 } 553 } 554 555 return -ENOENT; 556 } 557 558 /** 559 * xenbus_unmap_ring 560 * @dev: xenbus device 561 * @handles: grant handle array 562 * @nr_handles: number of handles in the array 563 * @vaddrs: addresses to unmap 564 * 565 * Unmap memory in this domain that was imported from another domain. 566 * Returns 0 on success and returns GNTST_* on error 567 * (see xen/include/interface/grant_table.h). 568 */ 569 static int xenbus_unmap_ring(struct xenbus_device *dev, grant_handle_t *handles, 570 unsigned int nr_handles, unsigned long *vaddrs) 571 { 572 struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS]; 573 int i; 574 int err; 575 576 if (nr_handles > XENBUS_MAX_RING_GRANTS) 577 return -EINVAL; 578 579 for (i = 0; i < nr_handles; i++) 580 gnttab_set_unmap_op(&unmap[i], vaddrs[i], 581 GNTMAP_host_map, handles[i]); 582 583 BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i)); 584 585 err = GNTST_okay; 586 for (i = 0; i < nr_handles; i++) { 587 if (unmap[i].status != GNTST_okay) { 588 xenbus_dev_error(dev, unmap[i].status, 589 "unmapping page at handle %d error %d", 590 handles[i], unmap[i].status); 591 err = unmap[i].status; 592 break; 593 } 594 } 595 596 return err; 597 } 598 599 static void xenbus_map_ring_setup_grant_hvm(unsigned long gfn, 600 unsigned int goffset, 601 unsigned int len, 602 void *data) 603 { 604 struct map_ring_valloc *info = data; 605 unsigned long vaddr = (unsigned long)gfn_to_virt(gfn); 606 607 info->phys_addrs[info->idx] = vaddr; 608 info->addrs[info->idx] = vaddr; 609 610 info->idx++; 611 } 612 613 static int xenbus_map_ring_hvm(struct xenbus_device *dev, 614 struct map_ring_valloc *info, 615 grant_ref_t *gnt_ref, 616 unsigned int nr_grefs, 617 void **vaddr) 618 { 619 struct xenbus_map_node *node = info->node; 620 int err; 621 void *addr; 622 bool leaked = false; 623 unsigned int nr_pages = XENBUS_PAGES(nr_grefs); 624 625 err = xen_alloc_unpopulated_pages(nr_pages, node->hvm.pages); 626 if (err) 627 goto out_err; 628 629 gnttab_foreach_grant(node->hvm.pages, nr_grefs, 630 xenbus_map_ring_setup_grant_hvm, 631 info); 632 633 err = __xenbus_map_ring(dev, gnt_ref, nr_grefs, node->handles, 634 info, GNTMAP_host_map, &leaked); 635 node->nr_handles = nr_grefs; 636 637 if (err) 638 goto out_free_ballooned_pages; 639 640 addr = vmap(node->hvm.pages, nr_pages, VM_MAP | VM_IOREMAP, 641 PAGE_KERNEL); 642 if (!addr) { 643 err = -ENOMEM; 644 goto out_xenbus_unmap_ring; 645 } 646 647 node->hvm.addr = addr; 648 649 spin_lock(&xenbus_valloc_lock); 650 list_add(&node->next, &xenbus_valloc_pages); 651 spin_unlock(&xenbus_valloc_lock); 652 653 *vaddr = addr; 654 info->node = NULL; 655 656 return 0; 657 658 out_xenbus_unmap_ring: 659 if (!leaked) 660 xenbus_unmap_ring(dev, node->handles, nr_grefs, info->addrs); 661 else 662 pr_alert("leaking %p size %u page(s)", 663 addr, nr_pages); 664 out_free_ballooned_pages: 665 if (!leaked) 666 xen_free_unpopulated_pages(nr_pages, node->hvm.pages); 667 out_err: 668 return err; 669 } 670 671 /** 672 * xenbus_unmap_ring_vfree 673 * @dev: xenbus device 674 * @vaddr: addr to unmap 675 * 676 * Based on Rusty Russell's skeleton driver's unmap_page. 677 * Unmap a page of memory in this domain that was imported from another domain. 678 * Use xenbus_unmap_ring_vfree if you mapped in your memory with 679 * xenbus_map_ring_valloc (it will free the virtual address space). 680 * Returns 0 on success and returns GNTST_* on error 681 * (see xen/include/interface/grant_table.h). 682 */ 683 int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr) 684 { 685 return ring_ops->unmap(dev, vaddr); 686 } 687 EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree); 688 689 #ifdef CONFIG_XEN_PV 690 static int map_ring_apply(pte_t *pte, unsigned long addr, void *data) 691 { 692 struct map_ring_valloc *info = data; 693 694 info->phys_addrs[info->idx++] = arbitrary_virt_to_machine(pte).maddr; 695 return 0; 696 } 697 698 static int xenbus_map_ring_pv(struct xenbus_device *dev, 699 struct map_ring_valloc *info, 700 grant_ref_t *gnt_refs, 701 unsigned int nr_grefs, 702 void **vaddr) 703 { 704 struct xenbus_map_node *node = info->node; 705 struct vm_struct *area; 706 bool leaked = false; 707 int err = -ENOMEM; 708 709 area = get_vm_area(XEN_PAGE_SIZE * nr_grefs, VM_IOREMAP); 710 if (!area) 711 return -ENOMEM; 712 if (apply_to_page_range(&init_mm, (unsigned long)area->addr, 713 XEN_PAGE_SIZE * nr_grefs, map_ring_apply, info)) 714 goto failed; 715 err = __xenbus_map_ring(dev, gnt_refs, nr_grefs, node->handles, 716 info, GNTMAP_host_map | GNTMAP_contains_pte, 717 &leaked); 718 if (err) 719 goto failed; 720 721 node->nr_handles = nr_grefs; 722 node->pv.area = area; 723 724 spin_lock(&xenbus_valloc_lock); 725 list_add(&node->next, &xenbus_valloc_pages); 726 spin_unlock(&xenbus_valloc_lock); 727 728 *vaddr = area->addr; 729 info->node = NULL; 730 731 return 0; 732 733 failed: 734 if (!leaked) 735 free_vm_area(area); 736 else 737 pr_alert("leaking VM area %p size %u page(s)", area, nr_grefs); 738 739 return err; 740 } 741 742 static int xenbus_unmap_ring_pv(struct xenbus_device *dev, void *vaddr) 743 { 744 struct xenbus_map_node *node; 745 struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS]; 746 unsigned int level; 747 int i; 748 bool leaked = false; 749 int err; 750 751 spin_lock(&xenbus_valloc_lock); 752 list_for_each_entry(node, &xenbus_valloc_pages, next) { 753 if (node->pv.area->addr == vaddr) { 754 list_del(&node->next); 755 goto found; 756 } 757 } 758 node = NULL; 759 found: 760 spin_unlock(&xenbus_valloc_lock); 761 762 if (!node) { 763 xenbus_dev_error(dev, -ENOENT, 764 "can't find mapped virtual address %p", vaddr); 765 return GNTST_bad_virt_addr; 766 } 767 768 for (i = 0; i < node->nr_handles; i++) { 769 unsigned long addr; 770 771 memset(&unmap[i], 0, sizeof(unmap[i])); 772 addr = (unsigned long)vaddr + (XEN_PAGE_SIZE * i); 773 unmap[i].host_addr = arbitrary_virt_to_machine( 774 lookup_address(addr, &level)).maddr; 775 unmap[i].dev_bus_addr = 0; 776 unmap[i].handle = node->handles[i]; 777 } 778 779 BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i)); 780 781 err = GNTST_okay; 782 leaked = false; 783 for (i = 0; i < node->nr_handles; i++) { 784 if (unmap[i].status != GNTST_okay) { 785 leaked = true; 786 xenbus_dev_error(dev, unmap[i].status, 787 "unmapping page at handle %d error %d", 788 node->handles[i], unmap[i].status); 789 err = unmap[i].status; 790 break; 791 } 792 } 793 794 if (!leaked) 795 free_vm_area(node->pv.area); 796 else 797 pr_alert("leaking VM area %p size %u page(s)", 798 node->pv.area, node->nr_handles); 799 800 kfree(node); 801 return err; 802 } 803 804 static const struct xenbus_ring_ops ring_ops_pv = { 805 .map = xenbus_map_ring_pv, 806 .unmap = xenbus_unmap_ring_pv, 807 }; 808 #endif 809 810 struct unmap_ring_hvm 811 { 812 unsigned int idx; 813 unsigned long addrs[XENBUS_MAX_RING_GRANTS]; 814 }; 815 816 static void xenbus_unmap_ring_setup_grant_hvm(unsigned long gfn, 817 unsigned int goffset, 818 unsigned int len, 819 void *data) 820 { 821 struct unmap_ring_hvm *info = data; 822 823 info->addrs[info->idx] = (unsigned long)gfn_to_virt(gfn); 824 825 info->idx++; 826 } 827 828 static int xenbus_unmap_ring_hvm(struct xenbus_device *dev, void *vaddr) 829 { 830 int rv; 831 struct xenbus_map_node *node; 832 void *addr; 833 struct unmap_ring_hvm info = { 834 .idx = 0, 835 }; 836 unsigned int nr_pages; 837 838 spin_lock(&xenbus_valloc_lock); 839 list_for_each_entry(node, &xenbus_valloc_pages, next) { 840 addr = node->hvm.addr; 841 if (addr == vaddr) { 842 list_del(&node->next); 843 goto found; 844 } 845 } 846 node = addr = NULL; 847 found: 848 spin_unlock(&xenbus_valloc_lock); 849 850 if (!node) { 851 xenbus_dev_error(dev, -ENOENT, 852 "can't find mapped virtual address %p", vaddr); 853 return GNTST_bad_virt_addr; 854 } 855 856 nr_pages = XENBUS_PAGES(node->nr_handles); 857 858 gnttab_foreach_grant(node->hvm.pages, node->nr_handles, 859 xenbus_unmap_ring_setup_grant_hvm, 860 &info); 861 862 rv = xenbus_unmap_ring(dev, node->handles, node->nr_handles, 863 info.addrs); 864 if (!rv) { 865 vunmap(vaddr); 866 xen_free_unpopulated_pages(nr_pages, node->hvm.pages); 867 } 868 else 869 WARN(1, "Leaking %p, size %u page(s)\n", vaddr, nr_pages); 870 871 kfree(node); 872 return rv; 873 } 874 875 /** 876 * xenbus_read_driver_state 877 * @path: path for driver 878 * 879 * Return the state of the driver rooted at the given store path, or 880 * XenbusStateUnknown if no state can be read. 881 */ 882 enum xenbus_state xenbus_read_driver_state(const char *path) 883 { 884 enum xenbus_state result; 885 int err = xenbus_gather(XBT_NIL, path, "state", "%d", &result, NULL); 886 if (err) 887 result = XenbusStateUnknown; 888 889 return result; 890 } 891 EXPORT_SYMBOL_GPL(xenbus_read_driver_state); 892 893 static const struct xenbus_ring_ops ring_ops_hvm = { 894 .map = xenbus_map_ring_hvm, 895 .unmap = xenbus_unmap_ring_hvm, 896 }; 897 898 void __init xenbus_ring_ops_init(void) 899 { 900 #ifdef CONFIG_XEN_PV 901 if (!xen_feature(XENFEAT_auto_translated_physmap)) 902 ring_ops = &ring_ops_pv; 903 else 904 #endif 905 ring_ops = &ring_ops_hvm; 906 } 907