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