1 /****************************************************************************** 2 * gntdev.c 3 * 4 * Device for accessing (in user-space) pages that have been granted by other 5 * domains. 6 * 7 * Copyright (c) 2006-2007, D G Murray. 8 * (c) 2009 Gerd Hoffmann <kraxel@redhat.com> 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 18 */ 19 20 #undef DEBUG 21 22 #include <linux/module.h> 23 #include <linux/kernel.h> 24 #include <linux/init.h> 25 #include <linux/miscdevice.h> 26 #include <linux/fs.h> 27 #include <linux/mm.h> 28 #include <linux/mman.h> 29 #include <linux/mmu_notifier.h> 30 #include <linux/types.h> 31 #include <linux/uaccess.h> 32 #include <linux/sched.h> 33 #include <linux/spinlock.h> 34 #include <linux/slab.h> 35 #include <linux/highmem.h> 36 37 #include <xen/xen.h> 38 #include <xen/grant_table.h> 39 #include <xen/balloon.h> 40 #include <xen/gntdev.h> 41 #include <xen/events.h> 42 #include <asm/xen/hypervisor.h> 43 #include <asm/xen/hypercall.h> 44 #include <asm/xen/page.h> 45 46 MODULE_LICENSE("GPL"); 47 MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, " 48 "Gerd Hoffmann <kraxel@redhat.com>"); 49 MODULE_DESCRIPTION("User-space granted page access driver"); 50 51 static int limit = 1024*1024; 52 module_param(limit, int, 0644); 53 MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped by " 54 "the gntdev device"); 55 56 static atomic_t pages_mapped = ATOMIC_INIT(0); 57 58 static int use_ptemod; 59 #define populate_freeable_maps use_ptemod 60 61 struct gntdev_priv { 62 /* maps with visible offsets in the file descriptor */ 63 struct list_head maps; 64 /* maps that are not visible; will be freed on munmap. 65 * Only populated if populate_freeable_maps == 1 */ 66 struct list_head freeable_maps; 67 /* lock protects maps and freeable_maps */ 68 spinlock_t lock; 69 struct mm_struct *mm; 70 struct mmu_notifier mn; 71 }; 72 73 struct unmap_notify { 74 int flags; 75 /* Address relative to the start of the grant_map */ 76 int addr; 77 int event; 78 }; 79 80 struct grant_map { 81 struct list_head next; 82 struct vm_area_struct *vma; 83 int index; 84 int count; 85 int flags; 86 atomic_t users; 87 struct unmap_notify notify; 88 struct ioctl_gntdev_grant_ref *grants; 89 struct gnttab_map_grant_ref *map_ops; 90 struct gnttab_unmap_grant_ref *unmap_ops; 91 struct gnttab_map_grant_ref *kmap_ops; 92 struct page **pages; 93 }; 94 95 static int unmap_grant_pages(struct grant_map *map, int offset, int pages); 96 97 /* ------------------------------------------------------------------ */ 98 99 static void gntdev_print_maps(struct gntdev_priv *priv, 100 char *text, int text_index) 101 { 102 #ifdef DEBUG 103 struct grant_map *map; 104 105 pr_debug("%s: maps list (priv %p)\n", __func__, priv); 106 list_for_each_entry(map, &priv->maps, next) 107 pr_debug(" index %2d, count %2d %s\n", 108 map->index, map->count, 109 map->index == text_index && text ? text : ""); 110 #endif 111 } 112 113 static void gntdev_free_map(struct grant_map *map) 114 { 115 if (map == NULL) 116 return; 117 118 if (map->pages) 119 free_xenballooned_pages(map->count, map->pages); 120 kfree(map->pages); 121 kfree(map->grants); 122 kfree(map->map_ops); 123 kfree(map->unmap_ops); 124 kfree(map->kmap_ops); 125 kfree(map); 126 } 127 128 static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count) 129 { 130 struct grant_map *add; 131 int i; 132 133 add = kzalloc(sizeof(struct grant_map), GFP_KERNEL); 134 if (NULL == add) 135 return NULL; 136 137 add->grants = kcalloc(count, sizeof(add->grants[0]), GFP_KERNEL); 138 add->map_ops = kcalloc(count, sizeof(add->map_ops[0]), GFP_KERNEL); 139 add->unmap_ops = kcalloc(count, sizeof(add->unmap_ops[0]), GFP_KERNEL); 140 add->kmap_ops = kcalloc(count, sizeof(add->kmap_ops[0]), GFP_KERNEL); 141 add->pages = kcalloc(count, sizeof(add->pages[0]), GFP_KERNEL); 142 if (NULL == add->grants || 143 NULL == add->map_ops || 144 NULL == add->unmap_ops || 145 NULL == add->kmap_ops || 146 NULL == add->pages) 147 goto err; 148 149 if (alloc_xenballooned_pages(count, add->pages, false /* lowmem */)) 150 goto err; 151 152 for (i = 0; i < count; i++) { 153 add->map_ops[i].handle = -1; 154 add->unmap_ops[i].handle = -1; 155 add->kmap_ops[i].handle = -1; 156 } 157 158 add->index = 0; 159 add->count = count; 160 atomic_set(&add->users, 1); 161 162 return add; 163 164 err: 165 gntdev_free_map(add); 166 return NULL; 167 } 168 169 static void gntdev_add_map(struct gntdev_priv *priv, struct grant_map *add) 170 { 171 struct grant_map *map; 172 173 list_for_each_entry(map, &priv->maps, next) { 174 if (add->index + add->count < map->index) { 175 list_add_tail(&add->next, &map->next); 176 goto done; 177 } 178 add->index = map->index + map->count; 179 } 180 list_add_tail(&add->next, &priv->maps); 181 182 done: 183 gntdev_print_maps(priv, "[new]", add->index); 184 } 185 186 static struct grant_map *gntdev_find_map_index(struct gntdev_priv *priv, 187 int index, int count) 188 { 189 struct grant_map *map; 190 191 list_for_each_entry(map, &priv->maps, next) { 192 if (map->index != index) 193 continue; 194 if (count && map->count != count) 195 continue; 196 return map; 197 } 198 return NULL; 199 } 200 201 static void gntdev_put_map(struct gntdev_priv *priv, struct grant_map *map) 202 { 203 if (!map) 204 return; 205 206 if (!atomic_dec_and_test(&map->users)) 207 return; 208 209 atomic_sub(map->count, &pages_mapped); 210 211 if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) { 212 notify_remote_via_evtchn(map->notify.event); 213 evtchn_put(map->notify.event); 214 } 215 216 if (populate_freeable_maps && priv) { 217 spin_lock(&priv->lock); 218 list_del(&map->next); 219 spin_unlock(&priv->lock); 220 } 221 222 if (map->pages && !use_ptemod) 223 unmap_grant_pages(map, 0, map->count); 224 gntdev_free_map(map); 225 } 226 227 /* ------------------------------------------------------------------ */ 228 229 static int find_grant_ptes(pte_t *pte, pgtable_t token, 230 unsigned long addr, void *data) 231 { 232 struct grant_map *map = data; 233 unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT; 234 int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte; 235 u64 pte_maddr; 236 237 BUG_ON(pgnr >= map->count); 238 pte_maddr = arbitrary_virt_to_machine(pte).maddr; 239 240 gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags, 241 map->grants[pgnr].ref, 242 map->grants[pgnr].domid); 243 gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags, 244 -1 /* handle */); 245 return 0; 246 } 247 248 static int map_grant_pages(struct grant_map *map) 249 { 250 int i, err = 0; 251 252 if (!use_ptemod) { 253 /* Note: it could already be mapped */ 254 if (map->map_ops[0].handle != -1) 255 return 0; 256 for (i = 0; i < map->count; i++) { 257 unsigned long addr = (unsigned long) 258 pfn_to_kaddr(page_to_pfn(map->pages[i])); 259 gnttab_set_map_op(&map->map_ops[i], addr, map->flags, 260 map->grants[i].ref, 261 map->grants[i].domid); 262 gnttab_set_unmap_op(&map->unmap_ops[i], addr, 263 map->flags, -1 /* handle */); 264 } 265 } else { 266 /* 267 * Setup the map_ops corresponding to the pte entries pointing 268 * to the kernel linear addresses of the struct pages. 269 * These ptes are completely different from the user ptes dealt 270 * with find_grant_ptes. 271 */ 272 for (i = 0; i < map->count; i++) { 273 unsigned level; 274 unsigned long address = (unsigned long) 275 pfn_to_kaddr(page_to_pfn(map->pages[i])); 276 pte_t *ptep; 277 u64 pte_maddr = 0; 278 BUG_ON(PageHighMem(map->pages[i])); 279 280 ptep = lookup_address(address, &level); 281 pte_maddr = arbitrary_virt_to_machine(ptep).maddr; 282 gnttab_set_map_op(&map->kmap_ops[i], pte_maddr, 283 map->flags | 284 GNTMAP_host_map | 285 GNTMAP_contains_pte, 286 map->grants[i].ref, 287 map->grants[i].domid); 288 } 289 } 290 291 pr_debug("map %d+%d\n", map->index, map->count); 292 err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL, 293 map->pages, map->count); 294 if (err) 295 return err; 296 297 for (i = 0; i < map->count; i++) { 298 if (map->map_ops[i].status) 299 err = -EINVAL; 300 else { 301 BUG_ON(map->map_ops[i].handle == -1); 302 map->unmap_ops[i].handle = map->map_ops[i].handle; 303 pr_debug("map handle=%d\n", map->map_ops[i].handle); 304 } 305 } 306 return err; 307 } 308 309 static int __unmap_grant_pages(struct grant_map *map, int offset, int pages) 310 { 311 int i, err = 0; 312 313 if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) { 314 int pgno = (map->notify.addr >> PAGE_SHIFT); 315 if (pgno >= offset && pgno < offset + pages) { 316 /* No need for kmap, pages are in lowmem */ 317 uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno])); 318 tmp[map->notify.addr & (PAGE_SIZE-1)] = 0; 319 map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE; 320 } 321 } 322 323 err = gnttab_unmap_refs(map->unmap_ops + offset, 324 use_ptemod ? map->kmap_ops + offset : NULL, map->pages + offset, 325 pages); 326 if (err) 327 return err; 328 329 for (i = 0; i < pages; i++) { 330 if (map->unmap_ops[offset+i].status) 331 err = -EINVAL; 332 pr_debug("unmap handle=%d st=%d\n", 333 map->unmap_ops[offset+i].handle, 334 map->unmap_ops[offset+i].status); 335 map->unmap_ops[offset+i].handle = -1; 336 } 337 return err; 338 } 339 340 static int unmap_grant_pages(struct grant_map *map, int offset, int pages) 341 { 342 int range, err = 0; 343 344 pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages); 345 346 /* It is possible the requested range will have a "hole" where we 347 * already unmapped some of the grants. Only unmap valid ranges. 348 */ 349 while (pages && !err) { 350 while (pages && map->unmap_ops[offset].handle == -1) { 351 offset++; 352 pages--; 353 } 354 range = 0; 355 while (range < pages) { 356 if (map->unmap_ops[offset+range].handle == -1) { 357 range--; 358 break; 359 } 360 range++; 361 } 362 err = __unmap_grant_pages(map, offset, range); 363 offset += range; 364 pages -= range; 365 } 366 367 return err; 368 } 369 370 /* ------------------------------------------------------------------ */ 371 372 static void gntdev_vma_open(struct vm_area_struct *vma) 373 { 374 struct grant_map *map = vma->vm_private_data; 375 376 pr_debug("gntdev_vma_open %p\n", vma); 377 atomic_inc(&map->users); 378 } 379 380 static void gntdev_vma_close(struct vm_area_struct *vma) 381 { 382 struct grant_map *map = vma->vm_private_data; 383 struct file *file = vma->vm_file; 384 struct gntdev_priv *priv = file->private_data; 385 386 pr_debug("gntdev_vma_close %p\n", vma); 387 if (use_ptemod) { 388 /* It is possible that an mmu notifier could be running 389 * concurrently, so take priv->lock to ensure that the vma won't 390 * vanishing during the unmap_grant_pages call, since we will 391 * spin here until that completes. Such a concurrent call will 392 * not do any unmapping, since that has been done prior to 393 * closing the vma, but it may still iterate the unmap_ops list. 394 */ 395 spin_lock(&priv->lock); 396 map->vma = NULL; 397 spin_unlock(&priv->lock); 398 } 399 vma->vm_private_data = NULL; 400 gntdev_put_map(priv, map); 401 } 402 403 static struct vm_operations_struct gntdev_vmops = { 404 .open = gntdev_vma_open, 405 .close = gntdev_vma_close, 406 }; 407 408 /* ------------------------------------------------------------------ */ 409 410 static void unmap_if_in_range(struct grant_map *map, 411 unsigned long start, unsigned long end) 412 { 413 unsigned long mstart, mend; 414 int err; 415 416 if (!map->vma) 417 return; 418 if (map->vma->vm_start >= end) 419 return; 420 if (map->vma->vm_end <= start) 421 return; 422 mstart = max(start, map->vma->vm_start); 423 mend = min(end, map->vma->vm_end); 424 pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n", 425 map->index, map->count, 426 map->vma->vm_start, map->vma->vm_end, 427 start, end, mstart, mend); 428 err = unmap_grant_pages(map, 429 (mstart - map->vma->vm_start) >> PAGE_SHIFT, 430 (mend - mstart) >> PAGE_SHIFT); 431 WARN_ON(err); 432 } 433 434 static void mn_invl_range_start(struct mmu_notifier *mn, 435 struct mm_struct *mm, 436 unsigned long start, unsigned long end) 437 { 438 struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn); 439 struct grant_map *map; 440 441 spin_lock(&priv->lock); 442 list_for_each_entry(map, &priv->maps, next) { 443 unmap_if_in_range(map, start, end); 444 } 445 list_for_each_entry(map, &priv->freeable_maps, next) { 446 unmap_if_in_range(map, start, end); 447 } 448 spin_unlock(&priv->lock); 449 } 450 451 static void mn_invl_page(struct mmu_notifier *mn, 452 struct mm_struct *mm, 453 unsigned long address) 454 { 455 mn_invl_range_start(mn, mm, address, address + PAGE_SIZE); 456 } 457 458 static void mn_release(struct mmu_notifier *mn, 459 struct mm_struct *mm) 460 { 461 struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn); 462 struct grant_map *map; 463 int err; 464 465 spin_lock(&priv->lock); 466 list_for_each_entry(map, &priv->maps, next) { 467 if (!map->vma) 468 continue; 469 pr_debug("map %d+%d (%lx %lx)\n", 470 map->index, map->count, 471 map->vma->vm_start, map->vma->vm_end); 472 err = unmap_grant_pages(map, /* offset */ 0, map->count); 473 WARN_ON(err); 474 } 475 list_for_each_entry(map, &priv->freeable_maps, next) { 476 if (!map->vma) 477 continue; 478 pr_debug("map %d+%d (%lx %lx)\n", 479 map->index, map->count, 480 map->vma->vm_start, map->vma->vm_end); 481 err = unmap_grant_pages(map, /* offset */ 0, map->count); 482 WARN_ON(err); 483 } 484 spin_unlock(&priv->lock); 485 } 486 487 static struct mmu_notifier_ops gntdev_mmu_ops = { 488 .release = mn_release, 489 .invalidate_page = mn_invl_page, 490 .invalidate_range_start = mn_invl_range_start, 491 }; 492 493 /* ------------------------------------------------------------------ */ 494 495 static int gntdev_open(struct inode *inode, struct file *flip) 496 { 497 struct gntdev_priv *priv; 498 int ret = 0; 499 500 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 501 if (!priv) 502 return -ENOMEM; 503 504 INIT_LIST_HEAD(&priv->maps); 505 INIT_LIST_HEAD(&priv->freeable_maps); 506 spin_lock_init(&priv->lock); 507 508 if (use_ptemod) { 509 priv->mm = get_task_mm(current); 510 if (!priv->mm) { 511 kfree(priv); 512 return -ENOMEM; 513 } 514 priv->mn.ops = &gntdev_mmu_ops; 515 ret = mmu_notifier_register(&priv->mn, priv->mm); 516 mmput(priv->mm); 517 } 518 519 if (ret) { 520 kfree(priv); 521 return ret; 522 } 523 524 flip->private_data = priv; 525 pr_debug("priv %p\n", priv); 526 527 return 0; 528 } 529 530 static int gntdev_release(struct inode *inode, struct file *flip) 531 { 532 struct gntdev_priv *priv = flip->private_data; 533 struct grant_map *map; 534 535 pr_debug("priv %p\n", priv); 536 537 while (!list_empty(&priv->maps)) { 538 map = list_entry(priv->maps.next, struct grant_map, next); 539 list_del(&map->next); 540 gntdev_put_map(NULL /* already removed */, map); 541 } 542 WARN_ON(!list_empty(&priv->freeable_maps)); 543 544 if (use_ptemod) 545 mmu_notifier_unregister(&priv->mn, priv->mm); 546 kfree(priv); 547 return 0; 548 } 549 550 static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv, 551 struct ioctl_gntdev_map_grant_ref __user *u) 552 { 553 struct ioctl_gntdev_map_grant_ref op; 554 struct grant_map *map; 555 int err; 556 557 if (copy_from_user(&op, u, sizeof(op)) != 0) 558 return -EFAULT; 559 pr_debug("priv %p, add %d\n", priv, op.count); 560 if (unlikely(op.count <= 0)) 561 return -EINVAL; 562 563 err = -ENOMEM; 564 map = gntdev_alloc_map(priv, op.count); 565 if (!map) 566 return err; 567 568 if (unlikely(atomic_add_return(op.count, &pages_mapped) > limit)) { 569 pr_debug("can't map: over limit\n"); 570 gntdev_put_map(NULL, map); 571 return err; 572 } 573 574 if (copy_from_user(map->grants, &u->refs, 575 sizeof(map->grants[0]) * op.count) != 0) { 576 gntdev_put_map(NULL, map); 577 return -EFAULT; 578 } 579 580 spin_lock(&priv->lock); 581 gntdev_add_map(priv, map); 582 op.index = map->index << PAGE_SHIFT; 583 spin_unlock(&priv->lock); 584 585 if (copy_to_user(u, &op, sizeof(op)) != 0) 586 return -EFAULT; 587 588 return 0; 589 } 590 591 static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv, 592 struct ioctl_gntdev_unmap_grant_ref __user *u) 593 { 594 struct ioctl_gntdev_unmap_grant_ref op; 595 struct grant_map *map; 596 int err = -ENOENT; 597 598 if (copy_from_user(&op, u, sizeof(op)) != 0) 599 return -EFAULT; 600 pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count); 601 602 spin_lock(&priv->lock); 603 map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count); 604 if (map) { 605 list_del(&map->next); 606 if (populate_freeable_maps) 607 list_add_tail(&map->next, &priv->freeable_maps); 608 err = 0; 609 } 610 spin_unlock(&priv->lock); 611 if (map) 612 gntdev_put_map(priv, map); 613 return err; 614 } 615 616 static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv, 617 struct ioctl_gntdev_get_offset_for_vaddr __user *u) 618 { 619 struct ioctl_gntdev_get_offset_for_vaddr op; 620 struct vm_area_struct *vma; 621 struct grant_map *map; 622 int rv = -EINVAL; 623 624 if (copy_from_user(&op, u, sizeof(op)) != 0) 625 return -EFAULT; 626 pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr); 627 628 down_read(¤t->mm->mmap_sem); 629 vma = find_vma(current->mm, op.vaddr); 630 if (!vma || vma->vm_ops != &gntdev_vmops) 631 goto out_unlock; 632 633 map = vma->vm_private_data; 634 if (!map) 635 goto out_unlock; 636 637 op.offset = map->index << PAGE_SHIFT; 638 op.count = map->count; 639 rv = 0; 640 641 out_unlock: 642 up_read(¤t->mm->mmap_sem); 643 644 if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0) 645 return -EFAULT; 646 return rv; 647 } 648 649 static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u) 650 { 651 struct ioctl_gntdev_unmap_notify op; 652 struct grant_map *map; 653 int rc; 654 int out_flags; 655 unsigned int out_event; 656 657 if (copy_from_user(&op, u, sizeof(op))) 658 return -EFAULT; 659 660 if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT)) 661 return -EINVAL; 662 663 /* We need to grab a reference to the event channel we are going to use 664 * to send the notify before releasing the reference we may already have 665 * (if someone has called this ioctl twice). This is required so that 666 * it is possible to change the clear_byte part of the notification 667 * without disturbing the event channel part, which may now be the last 668 * reference to that event channel. 669 */ 670 if (op.action & UNMAP_NOTIFY_SEND_EVENT) { 671 if (evtchn_get(op.event_channel_port)) 672 return -EINVAL; 673 } 674 675 out_flags = op.action; 676 out_event = op.event_channel_port; 677 678 spin_lock(&priv->lock); 679 680 list_for_each_entry(map, &priv->maps, next) { 681 uint64_t begin = map->index << PAGE_SHIFT; 682 uint64_t end = (map->index + map->count) << PAGE_SHIFT; 683 if (op.index >= begin && op.index < end) 684 goto found; 685 } 686 rc = -ENOENT; 687 goto unlock_out; 688 689 found: 690 if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) && 691 (map->flags & GNTMAP_readonly)) { 692 rc = -EINVAL; 693 goto unlock_out; 694 } 695 696 out_flags = map->notify.flags; 697 out_event = map->notify.event; 698 699 map->notify.flags = op.action; 700 map->notify.addr = op.index - (map->index << PAGE_SHIFT); 701 map->notify.event = op.event_channel_port; 702 703 rc = 0; 704 705 unlock_out: 706 spin_unlock(&priv->lock); 707 708 /* Drop the reference to the event channel we did not save in the map */ 709 if (out_flags & UNMAP_NOTIFY_SEND_EVENT) 710 evtchn_put(out_event); 711 712 return rc; 713 } 714 715 static long gntdev_ioctl(struct file *flip, 716 unsigned int cmd, unsigned long arg) 717 { 718 struct gntdev_priv *priv = flip->private_data; 719 void __user *ptr = (void __user *)arg; 720 721 switch (cmd) { 722 case IOCTL_GNTDEV_MAP_GRANT_REF: 723 return gntdev_ioctl_map_grant_ref(priv, ptr); 724 725 case IOCTL_GNTDEV_UNMAP_GRANT_REF: 726 return gntdev_ioctl_unmap_grant_ref(priv, ptr); 727 728 case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR: 729 return gntdev_ioctl_get_offset_for_vaddr(priv, ptr); 730 731 case IOCTL_GNTDEV_SET_UNMAP_NOTIFY: 732 return gntdev_ioctl_notify(priv, ptr); 733 734 default: 735 pr_debug("priv %p, unknown cmd %x\n", priv, cmd); 736 return -ENOIOCTLCMD; 737 } 738 739 return 0; 740 } 741 742 static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) 743 { 744 struct gntdev_priv *priv = flip->private_data; 745 int index = vma->vm_pgoff; 746 int count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; 747 struct grant_map *map; 748 int i, err = -EINVAL; 749 750 if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED)) 751 return -EINVAL; 752 753 pr_debug("map %d+%d at %lx (pgoff %lx)\n", 754 index, count, vma->vm_start, vma->vm_pgoff); 755 756 spin_lock(&priv->lock); 757 map = gntdev_find_map_index(priv, index, count); 758 if (!map) 759 goto unlock_out; 760 if (use_ptemod && map->vma) 761 goto unlock_out; 762 if (use_ptemod && priv->mm != vma->vm_mm) { 763 printk(KERN_WARNING "Huh? Other mm?\n"); 764 goto unlock_out; 765 } 766 767 atomic_inc(&map->users); 768 769 vma->vm_ops = &gntdev_vmops; 770 771 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; 772 773 if (use_ptemod) 774 vma->vm_flags |= VM_DONTCOPY; 775 776 vma->vm_private_data = map; 777 778 if (use_ptemod) 779 map->vma = vma; 780 781 if (map->flags) { 782 if ((vma->vm_flags & VM_WRITE) && 783 (map->flags & GNTMAP_readonly)) 784 goto out_unlock_put; 785 } else { 786 map->flags = GNTMAP_host_map; 787 if (!(vma->vm_flags & VM_WRITE)) 788 map->flags |= GNTMAP_readonly; 789 } 790 791 spin_unlock(&priv->lock); 792 793 if (use_ptemod) { 794 err = apply_to_page_range(vma->vm_mm, vma->vm_start, 795 vma->vm_end - vma->vm_start, 796 find_grant_ptes, map); 797 if (err) { 798 printk(KERN_WARNING "find_grant_ptes() failure.\n"); 799 goto out_put_map; 800 } 801 } 802 803 err = map_grant_pages(map); 804 if (err) 805 goto out_put_map; 806 807 if (!use_ptemod) { 808 for (i = 0; i < count; i++) { 809 err = vm_insert_page(vma, vma->vm_start + i*PAGE_SIZE, 810 map->pages[i]); 811 if (err) 812 goto out_put_map; 813 } 814 } 815 816 return 0; 817 818 unlock_out: 819 spin_unlock(&priv->lock); 820 return err; 821 822 out_unlock_put: 823 spin_unlock(&priv->lock); 824 out_put_map: 825 if (use_ptemod) 826 map->vma = NULL; 827 gntdev_put_map(priv, map); 828 return err; 829 } 830 831 static const struct file_operations gntdev_fops = { 832 .owner = THIS_MODULE, 833 .open = gntdev_open, 834 .release = gntdev_release, 835 .mmap = gntdev_mmap, 836 .unlocked_ioctl = gntdev_ioctl 837 }; 838 839 static struct miscdevice gntdev_miscdev = { 840 .minor = MISC_DYNAMIC_MINOR, 841 .name = "xen/gntdev", 842 .fops = &gntdev_fops, 843 }; 844 845 /* ------------------------------------------------------------------ */ 846 847 static int __init gntdev_init(void) 848 { 849 int err; 850 851 if (!xen_domain()) 852 return -ENODEV; 853 854 use_ptemod = xen_pv_domain(); 855 856 err = misc_register(&gntdev_miscdev); 857 if (err != 0) { 858 printk(KERN_ERR "Could not register gntdev device\n"); 859 return err; 860 } 861 return 0; 862 } 863 864 static void __exit gntdev_exit(void) 865 { 866 misc_deregister(&gntdev_miscdev); 867 } 868 869 module_init(gntdev_init); 870 module_exit(gntdev_exit); 871 872 /* ------------------------------------------------------------------ */ 873