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 56struct 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 72struct 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 85static DEFINE_SPINLOCK(xenbus_valloc_lock); 86static LIST_HEAD(xenbus_valloc_pages); 87 88struct 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 95static const struct xenbus_ring_ops *ring_ops __read_mostly; 96 97const 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} 112EXPORT_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 */ 128int 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} 152EXPORT_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 */ 170int 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} 196EXPORT_SYMBOL_GPL(xenbus_watch_pathfmt); 197 198static void xenbus_switch_fatal(struct xenbus_device *, int, int, 199 const char *, ...); 200 201static 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 225again: 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; 245abort: 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 */ 266int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state state) 267{ 268 return __xenbus_switch_state(dev, state, 0); 269} 270 271EXPORT_SYMBOL_GPL(xenbus_switch_state); 272 273int xenbus_frontend_closed(struct xenbus_device *dev) 274{ 275 xenbus_switch_state(dev, XenbusStateClosed); 276 complete(&dev->down); 277 return 0; 278} 279EXPORT_SYMBOL_GPL(xenbus_frontend_closed); 280 281static 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 */ 316void 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} 324EXPORT_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 337void 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} 347EXPORT_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 */ 353static 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 */ 378int 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} 408EXPORT_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 */ 417int 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} 434EXPORT_SYMBOL_GPL(xenbus_alloc_evtchn); 435 436 437/** 438 * Free an existing event channel. Returns 0 on success or -errno on error. 439 */ 440int 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} 453EXPORT_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 */ 470int 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} 495EXPORT_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 */ 500static 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 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, info->unmap, j)) 544 BUG(); 545 546 *leaked = false; 547 for (i = 0; i < j; i++) { 548 if (info->unmap[i].status != GNTST_okay) { 549 *leaked = true; 550 break; 551 } 552 } 553 554 return -ENOENT; 555} 556 557/** 558 * xenbus_unmap_ring 559 * @dev: xenbus device 560 * @handles: grant handle array 561 * @nr_handles: number of handles in the array 562 * @vaddrs: addresses to unmap 563 * 564 * Unmap memory in this domain that was imported from another domain. 565 * Returns 0 on success and returns GNTST_* on error 566 * (see xen/include/interface/grant_table.h). 567 */ 568static int xenbus_unmap_ring(struct xenbus_device *dev, grant_handle_t *handles, 569 unsigned int nr_handles, unsigned long *vaddrs) 570{ 571 struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS]; 572 int i; 573 int err; 574 575 if (nr_handles > XENBUS_MAX_RING_GRANTS) 576 return -EINVAL; 577 578 for (i = 0; i < nr_handles; i++) 579 gnttab_set_unmap_op(&unmap[i], vaddrs[i], 580 GNTMAP_host_map, handles[i]); 581 582 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i)) 583 BUG(); 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 599static 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 613static 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 */ 683int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr) 684{ 685 return ring_ops->unmap(dev, vaddr); 686} 687EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree); 688 689#ifdef CONFIG_XEN_PV 690static 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 698static 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 733failed: 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 742static 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 if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i)) 780 BUG(); 781 782 err = GNTST_okay; 783 leaked = false; 784 for (i = 0; i < node->nr_handles; i++) { 785 if (unmap[i].status != GNTST_okay) { 786 leaked = true; 787 xenbus_dev_error(dev, unmap[i].status, 788 "unmapping page at handle %d error %d", 789 node->handles[i], unmap[i].status); 790 err = unmap[i].status; 791 break; 792 } 793 } 794 795 if (!leaked) 796 free_vm_area(node->pv.area); 797 else 798 pr_alert("leaking VM area %p size %u page(s)", 799 node->pv.area, node->nr_handles); 800 801 kfree(node); 802 return err; 803} 804 805static const struct xenbus_ring_ops ring_ops_pv = { 806 .map = xenbus_map_ring_pv, 807 .unmap = xenbus_unmap_ring_pv, 808}; 809#endif 810 811struct unmap_ring_hvm 812{ 813 unsigned int idx; 814 unsigned long addrs[XENBUS_MAX_RING_GRANTS]; 815}; 816 817static void xenbus_unmap_ring_setup_grant_hvm(unsigned long gfn, 818 unsigned int goffset, 819 unsigned int len, 820 void *data) 821{ 822 struct unmap_ring_hvm *info = data; 823 824 info->addrs[info->idx] = (unsigned long)gfn_to_virt(gfn); 825 826 info->idx++; 827} 828 829static int xenbus_unmap_ring_hvm(struct xenbus_device *dev, void *vaddr) 830{ 831 int rv; 832 struct xenbus_map_node *node; 833 void *addr; 834 struct unmap_ring_hvm info = { 835 .idx = 0, 836 }; 837 unsigned int nr_pages; 838 839 spin_lock(&xenbus_valloc_lock); 840 list_for_each_entry(node, &xenbus_valloc_pages, next) { 841 addr = node->hvm.addr; 842 if (addr == vaddr) { 843 list_del(&node->next); 844 goto found; 845 } 846 } 847 node = addr = NULL; 848 found: 849 spin_unlock(&xenbus_valloc_lock); 850 851 if (!node) { 852 xenbus_dev_error(dev, -ENOENT, 853 "can't find mapped virtual address %p", vaddr); 854 return GNTST_bad_virt_addr; 855 } 856 857 nr_pages = XENBUS_PAGES(node->nr_handles); 858 859 gnttab_foreach_grant(node->hvm.pages, node->nr_handles, 860 xenbus_unmap_ring_setup_grant_hvm, 861 &info); 862 863 rv = xenbus_unmap_ring(dev, node->handles, node->nr_handles, 864 info.addrs); 865 if (!rv) { 866 vunmap(vaddr); 867 xen_free_unpopulated_pages(nr_pages, node->hvm.pages); 868 } 869 else 870 WARN(1, "Leaking %p, size %u page(s)\n", vaddr, nr_pages); 871 872 kfree(node); 873 return rv; 874} 875 876/** 877 * xenbus_read_driver_state 878 * @path: path for driver 879 * 880 * Return the state of the driver rooted at the given store path, or 881 * XenbusStateUnknown if no state can be read. 882 */ 883enum xenbus_state xenbus_read_driver_state(const char *path) 884{ 885 enum xenbus_state result; 886 int err = xenbus_gather(XBT_NIL, path, "state", "%d", &result, NULL); 887 if (err) 888 result = XenbusStateUnknown; 889 890 return result; 891} 892EXPORT_SYMBOL_GPL(xenbus_read_driver_state); 893 894static const struct xenbus_ring_ops ring_ops_hvm = { 895 .map = xenbus_map_ring_hvm, 896 .unmap = xenbus_unmap_ring_hvm, 897}; 898 899void __init xenbus_ring_ops_init(void) 900{ 901#ifdef CONFIG_XEN_PV 902 if (!xen_feature(XENFEAT_auto_translated_physmap)) 903 ring_ops = &ring_ops_pv; 904 else 905#endif 906 ring_ops = &ring_ops_hvm; 907} 908