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 * @will_handle: events queuing determine callback 120 * @callback: callback to register 121 * 122 * Register a @watch on the given path, using the given xenbus_watch structure 123 * for storage, @will_handle function as the callback to determine if each 124 * event need to be queued, and the given @callback function as the callback. 125 * On success, the given @path will be saved as @watch->node, and remains the 126 * caller's to free. On error, @watch->node will be NULL, the device will 127 * switch to %XenbusStateClosing, and the error will be saved in the store. 128 * 129 * Returns: %0 on success or -errno on error 130 */ 131int xenbus_watch_path(struct xenbus_device *dev, const char *path, 132 struct xenbus_watch *watch, 133 bool (*will_handle)(struct xenbus_watch *, 134 const char *, const char *), 135 void (*callback)(struct xenbus_watch *, 136 const char *, const char *)) 137{ 138 int err; 139 140 watch->node = path; 141 watch->will_handle = will_handle; 142 watch->callback = callback; 143 144 err = register_xenbus_watch(watch); 145 146 if (err) { 147 watch->node = NULL; 148 watch->will_handle = NULL; 149 watch->callback = NULL; 150 xenbus_dev_fatal(dev, err, "adding watch on %s", path); 151 } 152 153 return err; 154} 155EXPORT_SYMBOL_GPL(xenbus_watch_path); 156 157 158/** 159 * xenbus_watch_pathfmt - register a watch on a sprintf-formatted path 160 * @dev: xenbus device 161 * @watch: watch to register 162 * @will_handle: events queuing determine callback 163 * @callback: callback to register 164 * @pathfmt: format of path to watch 165 * 166 * Register a watch on the given @path, using the given xenbus_watch 167 * structure for storage, @will_handle function as the callback to determine if 168 * each event need to be queued, and the given @callback function as the 169 * callback. On success, the watched path (@path/@path2) will be saved 170 * as @watch->node, and becomes the caller's to kfree(). 171 * On error, watch->node will be NULL, so the caller has nothing to 172 * free, the device will switch to %XenbusStateClosing, and the error will be 173 * saved in the store. 174 * 175 * Returns: %0 on success or -errno on error 176 */ 177int xenbus_watch_pathfmt(struct xenbus_device *dev, 178 struct xenbus_watch *watch, 179 bool (*will_handle)(struct xenbus_watch *, 180 const char *, const char *), 181 void (*callback)(struct xenbus_watch *, 182 const char *, const char *), 183 const char *pathfmt, ...) 184{ 185 int err; 186 va_list ap; 187 char *path; 188 189 va_start(ap, pathfmt); 190 path = kvasprintf(GFP_NOIO | __GFP_HIGH, pathfmt, ap); 191 va_end(ap); 192 193 if (!path) { 194 xenbus_dev_fatal(dev, -ENOMEM, "allocating path for watch"); 195 return -ENOMEM; 196 } 197 err = xenbus_watch_path(dev, path, watch, will_handle, callback); 198 199 if (err) 200 kfree(path); 201 return err; 202} 203EXPORT_SYMBOL_GPL(xenbus_watch_pathfmt); 204 205static void xenbus_switch_fatal(struct xenbus_device *, int, int, 206 const char *, ...); 207 208static int 209__xenbus_switch_state(struct xenbus_device *dev, 210 enum xenbus_state state, int depth) 211{ 212 /* We check whether the state is currently set to the given value, and 213 if not, then the state is set. We don't want to unconditionally 214 write the given state, because we don't want to fire watches 215 unnecessarily. Furthermore, if the node has gone, we don't write 216 to it, as the device will be tearing down, and we don't want to 217 resurrect that directory. 218 219 Note that, because of this cached value of our state, this 220 function will not take a caller's Xenstore transaction 221 (something it was trying to in the past) because dev->state 222 would not get reset if the transaction was aborted. 223 */ 224 225 struct xenbus_transaction xbt; 226 int current_state; 227 int err, abort; 228 229 if (state == dev->state) 230 return 0; 231 232again: 233 abort = 1; 234 235 err = xenbus_transaction_start(&xbt); 236 if (err) { 237 xenbus_switch_fatal(dev, depth, err, "starting transaction"); 238 return 0; 239 } 240 241 err = xenbus_scanf(xbt, dev->nodename, "state", "%d", ¤t_state); 242 if (err != 1) 243 goto abort; 244 245 err = xenbus_printf(xbt, dev->nodename, "state", "%d", state); 246 if (err) { 247 xenbus_switch_fatal(dev, depth, err, "writing new state"); 248 goto abort; 249 } 250 251 abort = 0; 252abort: 253 err = xenbus_transaction_end(xbt, abort); 254 if (err) { 255 if (err == -EAGAIN && !abort) 256 goto again; 257 xenbus_switch_fatal(dev, depth, err, "ending transaction"); 258 } else 259 dev->state = state; 260 261 return 0; 262} 263 264/** 265 * xenbus_switch_state - save the new state of a driver 266 * @dev: xenbus device 267 * @state: new state 268 * 269 * Advertise in the store a change of the given driver to the given new_state. 270 * On error, the device will switch to XenbusStateClosing, and the error 271 * will be saved in the store. 272 * 273 * Returns: %0 on success or -errno on error 274 */ 275int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state state) 276{ 277 return __xenbus_switch_state(dev, state, 0); 278} 279 280EXPORT_SYMBOL_GPL(xenbus_switch_state); 281 282int xenbus_frontend_closed(struct xenbus_device *dev) 283{ 284 xenbus_switch_state(dev, XenbusStateClosed); 285 complete(&dev->down); 286 return 0; 287} 288EXPORT_SYMBOL_GPL(xenbus_frontend_closed); 289 290static void xenbus_va_dev_error(struct xenbus_device *dev, int err, 291 const char *fmt, va_list ap) 292{ 293 unsigned int len; 294 char *printf_buffer; 295 char *path_buffer; 296 297#define PRINTF_BUFFER_SIZE 4096 298 299 printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_KERNEL); 300 if (!printf_buffer) 301 return; 302 303 len = sprintf(printf_buffer, "%i ", -err); 304 vsnprintf(printf_buffer + len, PRINTF_BUFFER_SIZE - len, fmt, ap); 305 306 dev_err(&dev->dev, "%s\n", printf_buffer); 307 308 path_buffer = kasprintf(GFP_KERNEL, "error/%s", dev->nodename); 309 if (path_buffer) 310 xenbus_write(XBT_NIL, path_buffer, "error", printf_buffer); 311 312 kfree(printf_buffer); 313 kfree(path_buffer); 314} 315 316/** 317 * xenbus_dev_error - place an error message into the store 318 * @dev: xenbus device 319 * @err: error to report 320 * @fmt: error message format 321 * 322 * Report the given negative errno into the store, along with the given 323 * formatted message. 324 */ 325void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...) 326{ 327 va_list ap; 328 329 va_start(ap, fmt); 330 xenbus_va_dev_error(dev, err, fmt, ap); 331 va_end(ap); 332} 333EXPORT_SYMBOL_GPL(xenbus_dev_error); 334 335/** 336 * xenbus_dev_fatal - put an error messages into the store and then shutdown 337 * @dev: xenbus device 338 * @err: error to report 339 * @fmt: error message format 340 * 341 * Equivalent to xenbus_dev_error(dev, err, fmt, args), followed by 342 * xenbus_switch_state(dev, XenbusStateClosing) to schedule an orderly 343 * closedown of this driver and its peer. 344 */ 345 346void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...) 347{ 348 va_list ap; 349 350 va_start(ap, fmt); 351 xenbus_va_dev_error(dev, err, fmt, ap); 352 va_end(ap); 353 354 xenbus_switch_state(dev, XenbusStateClosing); 355} 356EXPORT_SYMBOL_GPL(xenbus_dev_fatal); 357 358/* 359 * Equivalent to xenbus_dev_fatal(dev, err, fmt, args), but helps 360 * avoiding recursion within xenbus_switch_state. 361 */ 362static void xenbus_switch_fatal(struct xenbus_device *dev, int depth, int err, 363 const char *fmt, ...) 364{ 365 va_list ap; 366 367 va_start(ap, fmt); 368 xenbus_va_dev_error(dev, err, fmt, ap); 369 va_end(ap); 370 371 if (!depth) 372 __xenbus_switch_state(dev, XenbusStateClosing, 1); 373} 374 375/* 376 * xenbus_setup_ring 377 * @dev: xenbus device 378 * @vaddr: pointer to starting virtual address of the ring 379 * @nr_pages: number of pages to be granted 380 * @grefs: grant reference array to be filled in 381 * 382 * Allocate physically contiguous pages for a shared ring buffer and grant it 383 * to the peer of the given device. The ring buffer is initially filled with 384 * zeroes. The virtual address of the ring is stored at @vaddr and the 385 * grant references are stored in the @grefs array. In case of error @vaddr 386 * will be set to NULL and @grefs will be filled with INVALID_GRANT_REF. 387 */ 388int xenbus_setup_ring(struct xenbus_device *dev, gfp_t gfp, void **vaddr, 389 unsigned int nr_pages, grant_ref_t *grefs) 390{ 391 unsigned long ring_size = nr_pages * XEN_PAGE_SIZE; 392 grant_ref_t gref_head; 393 unsigned int i; 394 void *addr; 395 int ret; 396 397 addr = *vaddr = alloc_pages_exact(ring_size, gfp | __GFP_ZERO); 398 if (!*vaddr) { 399 ret = -ENOMEM; 400 goto err; 401 } 402 403 ret = gnttab_alloc_grant_references(nr_pages, &gref_head); 404 if (ret) { 405 xenbus_dev_fatal(dev, ret, "granting access to %u ring pages", 406 nr_pages); 407 goto err; 408 } 409 410 for (i = 0; i < nr_pages; i++) { 411 unsigned long gfn; 412 413 if (is_vmalloc_addr(*vaddr)) 414 gfn = pfn_to_gfn(vmalloc_to_pfn(addr)); 415 else 416 gfn = virt_to_gfn(addr); 417 418 grefs[i] = gnttab_claim_grant_reference(&gref_head); 419 gnttab_grant_foreign_access_ref(grefs[i], dev->otherend_id, 420 gfn, 0); 421 422 addr += XEN_PAGE_SIZE; 423 } 424 425 return 0; 426 427 err: 428 if (*vaddr) 429 free_pages_exact(*vaddr, ring_size); 430 for (i = 0; i < nr_pages; i++) 431 grefs[i] = INVALID_GRANT_REF; 432 *vaddr = NULL; 433 434 return ret; 435} 436EXPORT_SYMBOL_GPL(xenbus_setup_ring); 437 438/* 439 * xenbus_teardown_ring 440 * @vaddr: starting virtual address of the ring 441 * @nr_pages: number of pages 442 * @grefs: grant reference array 443 * 444 * Remove grants for the shared ring buffer and free the associated memory. 445 * On return the grant reference array is filled with INVALID_GRANT_REF. 446 */ 447void xenbus_teardown_ring(void **vaddr, unsigned int nr_pages, 448 grant_ref_t *grefs) 449{ 450 unsigned int i; 451 452 for (i = 0; i < nr_pages; i++) { 453 if (grefs[i] != INVALID_GRANT_REF) { 454 gnttab_end_foreign_access(grefs[i], NULL); 455 grefs[i] = INVALID_GRANT_REF; 456 } 457 } 458 459 if (*vaddr) 460 free_pages_exact(*vaddr, nr_pages * XEN_PAGE_SIZE); 461 *vaddr = NULL; 462} 463EXPORT_SYMBOL_GPL(xenbus_teardown_ring); 464 465/* 466 * Allocate an event channel for the given xenbus_device, assigning the newly 467 * created local port to *port. Return 0 on success, or -errno on error. On 468 * error, the device will switch to XenbusStateClosing, and the error will be 469 * saved in the store. 470 */ 471int xenbus_alloc_evtchn(struct xenbus_device *dev, evtchn_port_t *port) 472{ 473 struct evtchn_alloc_unbound alloc_unbound; 474 int err; 475 476 alloc_unbound.dom = DOMID_SELF; 477 alloc_unbound.remote_dom = dev->otherend_id; 478 479 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, 480 &alloc_unbound); 481 if (err) 482 xenbus_dev_fatal(dev, err, "allocating event channel"); 483 else 484 *port = alloc_unbound.port; 485 486 return err; 487} 488EXPORT_SYMBOL_GPL(xenbus_alloc_evtchn); 489 490 491/* 492 * Free an existing event channel. Returns 0 on success or -errno on error. 493 */ 494int xenbus_free_evtchn(struct xenbus_device *dev, evtchn_port_t port) 495{ 496 struct evtchn_close close; 497 int err; 498 499 close.port = port; 500 501 err = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close); 502 if (err) 503 xenbus_dev_error(dev, err, "freeing event channel %u", port); 504 505 return err; 506} 507EXPORT_SYMBOL_GPL(xenbus_free_evtchn); 508 509 510/** 511 * xenbus_map_ring_valloc - allocate & map pages of VA space 512 * @dev: xenbus device 513 * @gnt_refs: grant reference array 514 * @nr_grefs: number of grant references 515 * @vaddr: pointer to address to be filled out by mapping 516 * 517 * Map @nr_grefs pages of memory into this domain from another 518 * domain's grant table. xenbus_map_ring_valloc allocates @nr_grefs 519 * pages of virtual address space, maps the pages to that address, and sets 520 * *vaddr to that address. If an error is returned, device will switch to 521 * XenbusStateClosing and the error message will be saved in XenStore. 522 * 523 * Returns: %0 on success or -errno on error 524 */ 525int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs, 526 unsigned int nr_grefs, void **vaddr) 527{ 528 int err; 529 struct map_ring_valloc *info; 530 531 *vaddr = NULL; 532 533 if (nr_grefs > XENBUS_MAX_RING_GRANTS) 534 return -EINVAL; 535 536 info = kzalloc(sizeof(*info), GFP_KERNEL); 537 if (!info) 538 return -ENOMEM; 539 540 info->node = kzalloc(sizeof(*info->node), GFP_KERNEL); 541 if (!info->node) 542 err = -ENOMEM; 543 else 544 err = ring_ops->map(dev, info, gnt_refs, nr_grefs, vaddr); 545 546 kfree(info->node); 547 kfree(info); 548 return err; 549} 550EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc); 551 552/* N.B. sizeof(phys_addr_t) doesn't always equal to sizeof(unsigned 553 * long), e.g. 32-on-64. Caller is responsible for preparing the 554 * right array to feed into this function */ 555static int __xenbus_map_ring(struct xenbus_device *dev, 556 grant_ref_t *gnt_refs, 557 unsigned int nr_grefs, 558 grant_handle_t *handles, 559 struct map_ring_valloc *info, 560 unsigned int flags, 561 bool *leaked) 562{ 563 int i, j; 564 565 if (nr_grefs > XENBUS_MAX_RING_GRANTS) 566 return -EINVAL; 567 568 for (i = 0; i < nr_grefs; i++) { 569 gnttab_set_map_op(&info->map[i], info->phys_addrs[i], flags, 570 gnt_refs[i], dev->otherend_id); 571 handles[i] = INVALID_GRANT_HANDLE; 572 } 573 574 gnttab_batch_map(info->map, i); 575 576 for (i = 0; i < nr_grefs; i++) { 577 if (info->map[i].status != GNTST_okay) { 578 xenbus_dev_fatal(dev, info->map[i].status, 579 "mapping in shared page %d from domain %d", 580 gnt_refs[i], dev->otherend_id); 581 goto fail; 582 } else 583 handles[i] = info->map[i].handle; 584 } 585 586 return 0; 587 588 fail: 589 for (i = j = 0; i < nr_grefs; i++) { 590 if (handles[i] != INVALID_GRANT_HANDLE) { 591 gnttab_set_unmap_op(&info->unmap[j], 592 info->phys_addrs[i], 593 GNTMAP_host_map, handles[i]); 594 j++; 595 } 596 } 597 598 BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, info->unmap, j)); 599 600 *leaked = false; 601 for (i = 0; i < j; i++) { 602 if (info->unmap[i].status != GNTST_okay) { 603 *leaked = true; 604 break; 605 } 606 } 607 608 return -ENOENT; 609} 610 611/** 612 * xenbus_unmap_ring - unmap memory from another domain 613 * @dev: xenbus device 614 * @handles: grant handle array 615 * @nr_handles: number of handles in the array 616 * @vaddrs: addresses to unmap 617 * 618 * Unmap memory in this domain that was imported from another domain. 619 * 620 * Returns: %0 on success or GNTST_* on error 621 * (see xen/include/interface/grant_table.h). 622 */ 623static int xenbus_unmap_ring(struct xenbus_device *dev, grant_handle_t *handles, 624 unsigned int nr_handles, unsigned long *vaddrs) 625{ 626 struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS]; 627 int i; 628 int err; 629 630 if (nr_handles > XENBUS_MAX_RING_GRANTS) 631 return -EINVAL; 632 633 for (i = 0; i < nr_handles; i++) 634 gnttab_set_unmap_op(&unmap[i], vaddrs[i], 635 GNTMAP_host_map, handles[i]); 636 637 BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i)); 638 639 err = GNTST_okay; 640 for (i = 0; i < nr_handles; i++) { 641 if (unmap[i].status != GNTST_okay) { 642 xenbus_dev_error(dev, unmap[i].status, 643 "unmapping page at handle %d error %d", 644 handles[i], unmap[i].status); 645 err = unmap[i].status; 646 break; 647 } 648 } 649 650 return err; 651} 652 653static void xenbus_map_ring_setup_grant_hvm(unsigned long gfn, 654 unsigned int goffset, 655 unsigned int len, 656 void *data) 657{ 658 struct map_ring_valloc *info = data; 659 unsigned long vaddr = (unsigned long)gfn_to_virt(gfn); 660 661 info->phys_addrs[info->idx] = vaddr; 662 info->addrs[info->idx] = vaddr; 663 664 info->idx++; 665} 666 667static int xenbus_map_ring_hvm(struct xenbus_device *dev, 668 struct map_ring_valloc *info, 669 grant_ref_t *gnt_ref, 670 unsigned int nr_grefs, 671 void **vaddr) 672{ 673 struct xenbus_map_node *node = info->node; 674 int err; 675 void *addr; 676 bool leaked = false; 677 unsigned int nr_pages = XENBUS_PAGES(nr_grefs); 678 679 err = xen_alloc_unpopulated_pages(nr_pages, node->hvm.pages); 680 if (err) 681 goto out_err; 682 683 gnttab_foreach_grant(node->hvm.pages, nr_grefs, 684 xenbus_map_ring_setup_grant_hvm, 685 info); 686 687 err = __xenbus_map_ring(dev, gnt_ref, nr_grefs, node->handles, 688 info, GNTMAP_host_map, &leaked); 689 node->nr_handles = nr_grefs; 690 691 if (err) 692 goto out_free_ballooned_pages; 693 694 addr = vmap(node->hvm.pages, nr_pages, VM_MAP | VM_IOREMAP, 695 PAGE_KERNEL); 696 if (!addr) { 697 err = -ENOMEM; 698 goto out_xenbus_unmap_ring; 699 } 700 701 node->hvm.addr = addr; 702 703 spin_lock(&xenbus_valloc_lock); 704 list_add(&node->next, &xenbus_valloc_pages); 705 spin_unlock(&xenbus_valloc_lock); 706 707 *vaddr = addr; 708 info->node = NULL; 709 710 return 0; 711 712 out_xenbus_unmap_ring: 713 if (!leaked) 714 xenbus_unmap_ring(dev, node->handles, nr_grefs, info->addrs); 715 else 716 pr_alert("leaking %p size %u page(s)", 717 addr, nr_pages); 718 out_free_ballooned_pages: 719 if (!leaked) 720 xen_free_unpopulated_pages(nr_pages, node->hvm.pages); 721 out_err: 722 return err; 723} 724 725/** 726 * xenbus_unmap_ring_vfree - unmap a page of memory from another domain 727 * @dev: xenbus device 728 * @vaddr: addr to unmap 729 * 730 * Based on Rusty Russell's skeleton driver's unmap_page. 731 * Unmap a page of memory in this domain that was imported from another domain. 732 * Use xenbus_unmap_ring_vfree if you mapped in your memory with 733 * xenbus_map_ring_valloc (it will free the virtual address space). 734 * 735 * Returns: %0 on success or GNTST_* on error 736 * (see xen/include/interface/grant_table.h). 737 */ 738int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr) 739{ 740 return ring_ops->unmap(dev, vaddr); 741} 742EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree); 743 744#ifdef CONFIG_XEN_PV 745static int map_ring_apply(pte_t *pte, unsigned long addr, void *data) 746{ 747 struct map_ring_valloc *info = data; 748 749 info->phys_addrs[info->idx++] = arbitrary_virt_to_machine(pte).maddr; 750 return 0; 751} 752 753static int xenbus_map_ring_pv(struct xenbus_device *dev, 754 struct map_ring_valloc *info, 755 grant_ref_t *gnt_refs, 756 unsigned int nr_grefs, 757 void **vaddr) 758{ 759 struct xenbus_map_node *node = info->node; 760 struct vm_struct *area; 761 bool leaked = false; 762 int err = -ENOMEM; 763 764 area = get_vm_area(XEN_PAGE_SIZE * nr_grefs, VM_IOREMAP); 765 if (!area) 766 return -ENOMEM; 767 if (apply_to_page_range(&init_mm, (unsigned long)area->addr, 768 XEN_PAGE_SIZE * nr_grefs, map_ring_apply, info)) 769 goto failed; 770 err = __xenbus_map_ring(dev, gnt_refs, nr_grefs, node->handles, 771 info, GNTMAP_host_map | GNTMAP_contains_pte, 772 &leaked); 773 if (err) 774 goto failed; 775 776 node->nr_handles = nr_grefs; 777 node->pv.area = area; 778 779 spin_lock(&xenbus_valloc_lock); 780 list_add(&node->next, &xenbus_valloc_pages); 781 spin_unlock(&xenbus_valloc_lock); 782 783 *vaddr = area->addr; 784 info->node = NULL; 785 786 return 0; 787 788failed: 789 if (!leaked) 790 free_vm_area(area); 791 else 792 pr_alert("leaking VM area %p size %u page(s)", area, nr_grefs); 793 794 return err; 795} 796 797static int xenbus_unmap_ring_pv(struct xenbus_device *dev, void *vaddr) 798{ 799 struct xenbus_map_node *node; 800 struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS]; 801 unsigned int level; 802 int i; 803 bool leaked = false; 804 int err; 805 806 spin_lock(&xenbus_valloc_lock); 807 list_for_each_entry(node, &xenbus_valloc_pages, next) { 808 if (node->pv.area->addr == vaddr) { 809 list_del(&node->next); 810 goto found; 811 } 812 } 813 node = NULL; 814 found: 815 spin_unlock(&xenbus_valloc_lock); 816 817 if (!node) { 818 xenbus_dev_error(dev, -ENOENT, 819 "can't find mapped virtual address %p", vaddr); 820 return GNTST_bad_virt_addr; 821 } 822 823 for (i = 0; i < node->nr_handles; i++) { 824 unsigned long addr; 825 826 memset(&unmap[i], 0, sizeof(unmap[i])); 827 addr = (unsigned long)vaddr + (XEN_PAGE_SIZE * i); 828 unmap[i].host_addr = arbitrary_virt_to_machine( 829 lookup_address(addr, &level)).maddr; 830 unmap[i].dev_bus_addr = 0; 831 unmap[i].handle = node->handles[i]; 832 } 833 834 BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i)); 835 836 err = GNTST_okay; 837 leaked = false; 838 for (i = 0; i < node->nr_handles; i++) { 839 if (unmap[i].status != GNTST_okay) { 840 leaked = true; 841 xenbus_dev_error(dev, unmap[i].status, 842 "unmapping page at handle %d error %d", 843 node->handles[i], unmap[i].status); 844 err = unmap[i].status; 845 break; 846 } 847 } 848 849 if (!leaked) 850 free_vm_area(node->pv.area); 851 else 852 pr_alert("leaking VM area %p size %u page(s)", 853 node->pv.area, node->nr_handles); 854 855 kfree(node); 856 return err; 857} 858 859static const struct xenbus_ring_ops ring_ops_pv = { 860 .map = xenbus_map_ring_pv, 861 .unmap = xenbus_unmap_ring_pv, 862}; 863#endif 864 865struct unmap_ring_hvm 866{ 867 unsigned int idx; 868 unsigned long addrs[XENBUS_MAX_RING_GRANTS]; 869}; 870 871static void xenbus_unmap_ring_setup_grant_hvm(unsigned long gfn, 872 unsigned int goffset, 873 unsigned int len, 874 void *data) 875{ 876 struct unmap_ring_hvm *info = data; 877 878 info->addrs[info->idx] = (unsigned long)gfn_to_virt(gfn); 879 880 info->idx++; 881} 882 883static int xenbus_unmap_ring_hvm(struct xenbus_device *dev, void *vaddr) 884{ 885 int rv; 886 struct xenbus_map_node *node; 887 void *addr; 888 struct unmap_ring_hvm info = { 889 .idx = 0, 890 }; 891 unsigned int nr_pages; 892 893 spin_lock(&xenbus_valloc_lock); 894 list_for_each_entry(node, &xenbus_valloc_pages, next) { 895 addr = node->hvm.addr; 896 if (addr == vaddr) { 897 list_del(&node->next); 898 goto found; 899 } 900 } 901 node = addr = NULL; 902 found: 903 spin_unlock(&xenbus_valloc_lock); 904 905 if (!node) { 906 xenbus_dev_error(dev, -ENOENT, 907 "can't find mapped virtual address %p", vaddr); 908 return GNTST_bad_virt_addr; 909 } 910 911 nr_pages = XENBUS_PAGES(node->nr_handles); 912 913 gnttab_foreach_grant(node->hvm.pages, node->nr_handles, 914 xenbus_unmap_ring_setup_grant_hvm, 915 &info); 916 917 rv = xenbus_unmap_ring(dev, node->handles, node->nr_handles, 918 info.addrs); 919 if (!rv) { 920 vunmap(vaddr); 921 xen_free_unpopulated_pages(nr_pages, node->hvm.pages); 922 } 923 else 924 WARN(1, "Leaking %p, size %u page(s)\n", vaddr, nr_pages); 925 926 kfree(node); 927 return rv; 928} 929 930/** 931 * xenbus_read_driver_state - read state from a store path 932 * @path: path for driver 933 * 934 * Returns: the state of the driver rooted at the given store path, or 935 * XenbusStateUnknown if no state can be read. 936 */ 937enum xenbus_state xenbus_read_driver_state(const char *path) 938{ 939 enum xenbus_state result; 940 int err = xenbus_gather(XBT_NIL, path, "state", "%d", &result, NULL); 941 if (err) 942 result = XenbusStateUnknown; 943 944 return result; 945} 946EXPORT_SYMBOL_GPL(xenbus_read_driver_state); 947 948static const struct xenbus_ring_ops ring_ops_hvm = { 949 .map = xenbus_map_ring_hvm, 950 .unmap = xenbus_unmap_ring_hvm, 951}; 952 953void __init xenbus_ring_ops_init(void) 954{ 955#ifdef CONFIG_XEN_PV 956 if (!xen_feature(XENFEAT_auto_translated_physmap)) 957 ring_ops = &ring_ops_pv; 958 else 959#endif 960 ring_ops = &ring_ops_hvm; 961} 962