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_setup_ring 368 * @dev: xenbus device 369 * @vaddr: pointer to 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 * Allocate physically contiguous pages for a shared ring buffer and grant it 374 * to the peer of the given device. The ring buffer is initially filled with 375 * zeroes. The virtual address of the ring is stored at @vaddr and the 376 * grant references are stored in the @grefs array. In case of error @vaddr 377 * will be set to NULL and @grefs will be filled with INVALID_GRANT_REF. 378 */ 379int xenbus_setup_ring(struct xenbus_device *dev, gfp_t gfp, void **vaddr, 380 unsigned int nr_pages, grant_ref_t *grefs) 381{ 382 unsigned long ring_size = nr_pages * XEN_PAGE_SIZE; 383 grant_ref_t gref_head; 384 unsigned int i; 385 void *addr; 386 int ret; 387 388 addr = *vaddr = alloc_pages_exact(ring_size, gfp | __GFP_ZERO); 389 if (!*vaddr) { 390 ret = -ENOMEM; 391 goto err; 392 } 393 394 ret = gnttab_alloc_grant_references(nr_pages, &gref_head); 395 if (ret) { 396 xenbus_dev_fatal(dev, ret, "granting access to %u ring pages", 397 nr_pages); 398 goto err; 399 } 400 401 for (i = 0; i < nr_pages; i++) { 402 unsigned long gfn; 403 404 if (is_vmalloc_addr(*vaddr)) 405 gfn = pfn_to_gfn(vmalloc_to_pfn(addr)); 406 else 407 gfn = virt_to_gfn(addr); 408 409 grefs[i] = gnttab_claim_grant_reference(&gref_head); 410 gnttab_grant_foreign_access_ref(grefs[i], dev->otherend_id, 411 gfn, 0); 412 413 addr += XEN_PAGE_SIZE; 414 } 415 416 return 0; 417 418 err: 419 if (*vaddr) 420 free_pages_exact(*vaddr, ring_size); 421 for (i = 0; i < nr_pages; i++) 422 grefs[i] = INVALID_GRANT_REF; 423 *vaddr = NULL; 424 425 return ret; 426} 427EXPORT_SYMBOL_GPL(xenbus_setup_ring); 428 429/* 430 * xenbus_teardown_ring 431 * @vaddr: starting virtual address of the ring 432 * @nr_pages: number of pages 433 * @grefs: grant reference array 434 * 435 * Remove grants for the shared ring buffer and free the associated memory. 436 * On return the grant reference array is filled with INVALID_GRANT_REF. 437 */ 438void xenbus_teardown_ring(void **vaddr, unsigned int nr_pages, 439 grant_ref_t *grefs) 440{ 441 unsigned int i; 442 443 for (i = 0; i < nr_pages; i++) { 444 if (grefs[i] != INVALID_GRANT_REF) { 445 gnttab_end_foreign_access(grefs[i], NULL); 446 grefs[i] = INVALID_GRANT_REF; 447 } 448 } 449 450 if (*vaddr) 451 free_pages_exact(*vaddr, nr_pages * XEN_PAGE_SIZE); 452 *vaddr = NULL; 453} 454EXPORT_SYMBOL_GPL(xenbus_teardown_ring); 455 456/** 457 * Allocate an event channel for the given xenbus_device, assigning the newly 458 * created local port to *port. Return 0 on success, or -errno on error. On 459 * error, the device will switch to XenbusStateClosing, and the error will be 460 * saved in the store. 461 */ 462int xenbus_alloc_evtchn(struct xenbus_device *dev, evtchn_port_t *port) 463{ 464 struct evtchn_alloc_unbound alloc_unbound; 465 int err; 466 467 alloc_unbound.dom = DOMID_SELF; 468 alloc_unbound.remote_dom = dev->otherend_id; 469 470 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, 471 &alloc_unbound); 472 if (err) 473 xenbus_dev_fatal(dev, err, "allocating event channel"); 474 else 475 *port = alloc_unbound.port; 476 477 return err; 478} 479EXPORT_SYMBOL_GPL(xenbus_alloc_evtchn); 480 481 482/** 483 * Free an existing event channel. Returns 0 on success or -errno on error. 484 */ 485int xenbus_free_evtchn(struct xenbus_device *dev, evtchn_port_t port) 486{ 487 struct evtchn_close close; 488 int err; 489 490 close.port = port; 491 492 err = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close); 493 if (err) 494 xenbus_dev_error(dev, err, "freeing event channel %u", port); 495 496 return err; 497} 498EXPORT_SYMBOL_GPL(xenbus_free_evtchn); 499 500 501/** 502 * xenbus_map_ring_valloc 503 * @dev: xenbus device 504 * @gnt_refs: grant reference array 505 * @nr_grefs: number of grant references 506 * @vaddr: pointer to address to be filled out by mapping 507 * 508 * Map @nr_grefs pages of memory into this domain from another 509 * domain's grant table. xenbus_map_ring_valloc allocates @nr_grefs 510 * pages of virtual address space, maps the pages to that address, and 511 * sets *vaddr to that address. Returns 0 on success, and -errno on 512 * error. If an error is returned, device will switch to 513 * XenbusStateClosing and the error message will be saved in XenStore. 514 */ 515int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs, 516 unsigned int nr_grefs, void **vaddr) 517{ 518 int err; 519 struct map_ring_valloc *info; 520 521 *vaddr = NULL; 522 523 if (nr_grefs > XENBUS_MAX_RING_GRANTS) 524 return -EINVAL; 525 526 info = kzalloc(sizeof(*info), GFP_KERNEL); 527 if (!info) 528 return -ENOMEM; 529 530 info->node = kzalloc(sizeof(*info->node), GFP_KERNEL); 531 if (!info->node) 532 err = -ENOMEM; 533 else 534 err = ring_ops->map(dev, info, gnt_refs, nr_grefs, vaddr); 535 536 kfree(info->node); 537 kfree(info); 538 return err; 539} 540EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc); 541 542/* N.B. sizeof(phys_addr_t) doesn't always equal to sizeof(unsigned 543 * long), e.g. 32-on-64. Caller is responsible for preparing the 544 * right array to feed into this function */ 545static int __xenbus_map_ring(struct xenbus_device *dev, 546 grant_ref_t *gnt_refs, 547 unsigned int nr_grefs, 548 grant_handle_t *handles, 549 struct map_ring_valloc *info, 550 unsigned int flags, 551 bool *leaked) 552{ 553 int i, j; 554 555 if (nr_grefs > XENBUS_MAX_RING_GRANTS) 556 return -EINVAL; 557 558 for (i = 0; i < nr_grefs; i++) { 559 gnttab_set_map_op(&info->map[i], info->phys_addrs[i], flags, 560 gnt_refs[i], dev->otherend_id); 561 handles[i] = INVALID_GRANT_HANDLE; 562 } 563 564 gnttab_batch_map(info->map, i); 565 566 for (i = 0; i < nr_grefs; i++) { 567 if (info->map[i].status != GNTST_okay) { 568 xenbus_dev_fatal(dev, info->map[i].status, 569 "mapping in shared page %d from domain %d", 570 gnt_refs[i], dev->otherend_id); 571 goto fail; 572 } else 573 handles[i] = info->map[i].handle; 574 } 575 576 return 0; 577 578 fail: 579 for (i = j = 0; i < nr_grefs; i++) { 580 if (handles[i] != INVALID_GRANT_HANDLE) { 581 gnttab_set_unmap_op(&info->unmap[j], 582 info->phys_addrs[i], 583 GNTMAP_host_map, handles[i]); 584 j++; 585 } 586 } 587 588 BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, info->unmap, j)); 589 590 *leaked = false; 591 for (i = 0; i < j; i++) { 592 if (info->unmap[i].status != GNTST_okay) { 593 *leaked = true; 594 break; 595 } 596 } 597 598 return -ENOENT; 599} 600 601/** 602 * xenbus_unmap_ring 603 * @dev: xenbus device 604 * @handles: grant handle array 605 * @nr_handles: number of handles in the array 606 * @vaddrs: addresses to unmap 607 * 608 * Unmap memory in this domain that was imported from another domain. 609 * Returns 0 on success and returns GNTST_* on error 610 * (see xen/include/interface/grant_table.h). 611 */ 612static int xenbus_unmap_ring(struct xenbus_device *dev, grant_handle_t *handles, 613 unsigned int nr_handles, unsigned long *vaddrs) 614{ 615 struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS]; 616 int i; 617 int err; 618 619 if (nr_handles > XENBUS_MAX_RING_GRANTS) 620 return -EINVAL; 621 622 for (i = 0; i < nr_handles; i++) 623 gnttab_set_unmap_op(&unmap[i], vaddrs[i], 624 GNTMAP_host_map, handles[i]); 625 626 BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i)); 627 628 err = GNTST_okay; 629 for (i = 0; i < nr_handles; i++) { 630 if (unmap[i].status != GNTST_okay) { 631 xenbus_dev_error(dev, unmap[i].status, 632 "unmapping page at handle %d error %d", 633 handles[i], unmap[i].status); 634 err = unmap[i].status; 635 break; 636 } 637 } 638 639 return err; 640} 641 642static void xenbus_map_ring_setup_grant_hvm(unsigned long gfn, 643 unsigned int goffset, 644 unsigned int len, 645 void *data) 646{ 647 struct map_ring_valloc *info = data; 648 unsigned long vaddr = (unsigned long)gfn_to_virt(gfn); 649 650 info->phys_addrs[info->idx] = vaddr; 651 info->addrs[info->idx] = vaddr; 652 653 info->idx++; 654} 655 656static int xenbus_map_ring_hvm(struct xenbus_device *dev, 657 struct map_ring_valloc *info, 658 grant_ref_t *gnt_ref, 659 unsigned int nr_grefs, 660 void **vaddr) 661{ 662 struct xenbus_map_node *node = info->node; 663 int err; 664 void *addr; 665 bool leaked = false; 666 unsigned int nr_pages = XENBUS_PAGES(nr_grefs); 667 668 err = xen_alloc_unpopulated_pages(nr_pages, node->hvm.pages); 669 if (err) 670 goto out_err; 671 672 gnttab_foreach_grant(node->hvm.pages, nr_grefs, 673 xenbus_map_ring_setup_grant_hvm, 674 info); 675 676 err = __xenbus_map_ring(dev, gnt_ref, nr_grefs, node->handles, 677 info, GNTMAP_host_map, &leaked); 678 node->nr_handles = nr_grefs; 679 680 if (err) 681 goto out_free_ballooned_pages; 682 683 addr = vmap(node->hvm.pages, nr_pages, VM_MAP | VM_IOREMAP, 684 PAGE_KERNEL); 685 if (!addr) { 686 err = -ENOMEM; 687 goto out_xenbus_unmap_ring; 688 } 689 690 node->hvm.addr = addr; 691 692 spin_lock(&xenbus_valloc_lock); 693 list_add(&node->next, &xenbus_valloc_pages); 694 spin_unlock(&xenbus_valloc_lock); 695 696 *vaddr = addr; 697 info->node = NULL; 698 699 return 0; 700 701 out_xenbus_unmap_ring: 702 if (!leaked) 703 xenbus_unmap_ring(dev, node->handles, nr_grefs, info->addrs); 704 else 705 pr_alert("leaking %p size %u page(s)", 706 addr, nr_pages); 707 out_free_ballooned_pages: 708 if (!leaked) 709 xen_free_unpopulated_pages(nr_pages, node->hvm.pages); 710 out_err: 711 return err; 712} 713 714/** 715 * xenbus_unmap_ring_vfree 716 * @dev: xenbus device 717 * @vaddr: addr to unmap 718 * 719 * Based on Rusty Russell's skeleton driver's unmap_page. 720 * Unmap a page of memory in this domain that was imported from another domain. 721 * Use xenbus_unmap_ring_vfree if you mapped in your memory with 722 * xenbus_map_ring_valloc (it will free the virtual address space). 723 * Returns 0 on success and returns GNTST_* on error 724 * (see xen/include/interface/grant_table.h). 725 */ 726int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr) 727{ 728 return ring_ops->unmap(dev, vaddr); 729} 730EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree); 731 732#ifdef CONFIG_XEN_PV 733static int map_ring_apply(pte_t *pte, unsigned long addr, void *data) 734{ 735 struct map_ring_valloc *info = data; 736 737 info->phys_addrs[info->idx++] = arbitrary_virt_to_machine(pte).maddr; 738 return 0; 739} 740 741static int xenbus_map_ring_pv(struct xenbus_device *dev, 742 struct map_ring_valloc *info, 743 grant_ref_t *gnt_refs, 744 unsigned int nr_grefs, 745 void **vaddr) 746{ 747 struct xenbus_map_node *node = info->node; 748 struct vm_struct *area; 749 bool leaked = false; 750 int err = -ENOMEM; 751 752 area = get_vm_area(XEN_PAGE_SIZE * nr_grefs, VM_IOREMAP); 753 if (!area) 754 return -ENOMEM; 755 if (apply_to_page_range(&init_mm, (unsigned long)area->addr, 756 XEN_PAGE_SIZE * nr_grefs, map_ring_apply, info)) 757 goto failed; 758 err = __xenbus_map_ring(dev, gnt_refs, nr_grefs, node->handles, 759 info, GNTMAP_host_map | GNTMAP_contains_pte, 760 &leaked); 761 if (err) 762 goto failed; 763 764 node->nr_handles = nr_grefs; 765 node->pv.area = area; 766 767 spin_lock(&xenbus_valloc_lock); 768 list_add(&node->next, &xenbus_valloc_pages); 769 spin_unlock(&xenbus_valloc_lock); 770 771 *vaddr = area->addr; 772 info->node = NULL; 773 774 return 0; 775 776failed: 777 if (!leaked) 778 free_vm_area(area); 779 else 780 pr_alert("leaking VM area %p size %u page(s)", area, nr_grefs); 781 782 return err; 783} 784 785static int xenbus_unmap_ring_pv(struct xenbus_device *dev, void *vaddr) 786{ 787 struct xenbus_map_node *node; 788 struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS]; 789 unsigned int level; 790 int i; 791 bool leaked = false; 792 int err; 793 794 spin_lock(&xenbus_valloc_lock); 795 list_for_each_entry(node, &xenbus_valloc_pages, next) { 796 if (node->pv.area->addr == vaddr) { 797 list_del(&node->next); 798 goto found; 799 } 800 } 801 node = NULL; 802 found: 803 spin_unlock(&xenbus_valloc_lock); 804 805 if (!node) { 806 xenbus_dev_error(dev, -ENOENT, 807 "can't find mapped virtual address %p", vaddr); 808 return GNTST_bad_virt_addr; 809 } 810 811 for (i = 0; i < node->nr_handles; i++) { 812 unsigned long addr; 813 814 memset(&unmap[i], 0, sizeof(unmap[i])); 815 addr = (unsigned long)vaddr + (XEN_PAGE_SIZE * i); 816 unmap[i].host_addr = arbitrary_virt_to_machine( 817 lookup_address(addr, &level)).maddr; 818 unmap[i].dev_bus_addr = 0; 819 unmap[i].handle = node->handles[i]; 820 } 821 822 BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i)); 823 824 err = GNTST_okay; 825 leaked = false; 826 for (i = 0; i < node->nr_handles; i++) { 827 if (unmap[i].status != GNTST_okay) { 828 leaked = true; 829 xenbus_dev_error(dev, unmap[i].status, 830 "unmapping page at handle %d error %d", 831 node->handles[i], unmap[i].status); 832 err = unmap[i].status; 833 break; 834 } 835 } 836 837 if (!leaked) 838 free_vm_area(node->pv.area); 839 else 840 pr_alert("leaking VM area %p size %u page(s)", 841 node->pv.area, node->nr_handles); 842 843 kfree(node); 844 return err; 845} 846 847static const struct xenbus_ring_ops ring_ops_pv = { 848 .map = xenbus_map_ring_pv, 849 .unmap = xenbus_unmap_ring_pv, 850}; 851#endif 852 853struct unmap_ring_hvm 854{ 855 unsigned int idx; 856 unsigned long addrs[XENBUS_MAX_RING_GRANTS]; 857}; 858 859static void xenbus_unmap_ring_setup_grant_hvm(unsigned long gfn, 860 unsigned int goffset, 861 unsigned int len, 862 void *data) 863{ 864 struct unmap_ring_hvm *info = data; 865 866 info->addrs[info->idx] = (unsigned long)gfn_to_virt(gfn); 867 868 info->idx++; 869} 870 871static int xenbus_unmap_ring_hvm(struct xenbus_device *dev, void *vaddr) 872{ 873 int rv; 874 struct xenbus_map_node *node; 875 void *addr; 876 struct unmap_ring_hvm info = { 877 .idx = 0, 878 }; 879 unsigned int nr_pages; 880 881 spin_lock(&xenbus_valloc_lock); 882 list_for_each_entry(node, &xenbus_valloc_pages, next) { 883 addr = node->hvm.addr; 884 if (addr == vaddr) { 885 list_del(&node->next); 886 goto found; 887 } 888 } 889 node = addr = NULL; 890 found: 891 spin_unlock(&xenbus_valloc_lock); 892 893 if (!node) { 894 xenbus_dev_error(dev, -ENOENT, 895 "can't find mapped virtual address %p", vaddr); 896 return GNTST_bad_virt_addr; 897 } 898 899 nr_pages = XENBUS_PAGES(node->nr_handles); 900 901 gnttab_foreach_grant(node->hvm.pages, node->nr_handles, 902 xenbus_unmap_ring_setup_grant_hvm, 903 &info); 904 905 rv = xenbus_unmap_ring(dev, node->handles, node->nr_handles, 906 info.addrs); 907 if (!rv) { 908 vunmap(vaddr); 909 xen_free_unpopulated_pages(nr_pages, node->hvm.pages); 910 } 911 else 912 WARN(1, "Leaking %p, size %u page(s)\n", vaddr, nr_pages); 913 914 kfree(node); 915 return rv; 916} 917 918/** 919 * xenbus_read_driver_state 920 * @path: path for driver 921 * 922 * Return the state of the driver rooted at the given store path, or 923 * XenbusStateUnknown if no state can be read. 924 */ 925enum xenbus_state xenbus_read_driver_state(const char *path) 926{ 927 enum xenbus_state result; 928 int err = xenbus_gather(XBT_NIL, path, "state", "%d", &result, NULL); 929 if (err) 930 result = XenbusStateUnknown; 931 932 return result; 933} 934EXPORT_SYMBOL_GPL(xenbus_read_driver_state); 935 936static const struct xenbus_ring_ops ring_ops_hvm = { 937 .map = xenbus_map_ring_hvm, 938 .unmap = xenbus_unmap_ring_hvm, 939}; 940 941void __init xenbus_ring_ops_init(void) 942{ 943#ifdef CONFIG_XEN_PV 944 if (!xen_feature(XENFEAT_auto_translated_physmap)) 945 ring_ops = &ring_ops_pv; 946 else 947#endif 948 ring_ops = &ring_ops_hvm; 949} 950