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