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 level; 276 unsigned long address = (unsigned long) 277 pfn_to_kaddr(page_to_pfn(map->pages[i])); 278 pte_t *ptep; 279 u64 pte_maddr = 0; 280 BUG_ON(PageHighMem(map->pages[i])); 281 282 ptep = lookup_address(address, &level); 283 pte_maddr = arbitrary_virt_to_machine(ptep).maddr; 284 gnttab_set_map_op(&map->kmap_ops[i], pte_maddr, 285 map->flags | 286 GNTMAP_host_map | 287 GNTMAP_contains_pte, 288 map->grants[i].ref, 289 map->grants[i].domid); 290 } 291 } 292 293 pr_debug("map %d+%d\n", map->index, map->count); 294 err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL, 295 map->pages, map->count); 296 if (err) 297 return err; 298 299 for (i = 0; i < map->count; i++) { 300 if (map->map_ops[i].status) 301 err = -EINVAL; 302 else { 303 BUG_ON(map->map_ops[i].handle == -1); 304 map->unmap_ops[i].handle = map->map_ops[i].handle; 305 pr_debug("map handle=%d\n", map->map_ops[i].handle); 306 } 307 } 308 return err; 309 } 310 311 static int __unmap_grant_pages(struct grant_map *map, int offset, int pages) 312 { 313 int i, err = 0; 314 315 if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) { 316 int pgno = (map->notify.addr >> PAGE_SHIFT); 317 if (pgno >= offset && pgno < offset + pages) { 318 /* No need for kmap, pages are in lowmem */ 319 uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno])); 320 tmp[map->notify.addr & (PAGE_SIZE-1)] = 0; 321 map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE; 322 } 323 } 324 325 err = gnttab_unmap_refs(map->unmap_ops + offset, 326 use_ptemod ? map->kmap_ops + offset : NULL, map->pages + offset, 327 pages); 328 if (err) 329 return err; 330 331 for (i = 0; i < pages; i++) { 332 if (map->unmap_ops[offset+i].status) 333 err = -EINVAL; 334 pr_debug("unmap handle=%d st=%d\n", 335 map->unmap_ops[offset+i].handle, 336 map->unmap_ops[offset+i].status); 337 map->unmap_ops[offset+i].handle = -1; 338 } 339 return err; 340 } 341 342 static int unmap_grant_pages(struct grant_map *map, int offset, int pages) 343 { 344 int range, err = 0; 345 346 pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages); 347 348 /* It is possible the requested range will have a "hole" where we 349 * already unmapped some of the grants. Only unmap valid ranges. 350 */ 351 while (pages && !err) { 352 while (pages && map->unmap_ops[offset].handle == -1) { 353 offset++; 354 pages--; 355 } 356 range = 0; 357 while (range < pages) { 358 if (map->unmap_ops[offset+range].handle == -1) { 359 range--; 360 break; 361 } 362 range++; 363 } 364 err = __unmap_grant_pages(map, offset, range); 365 offset += range; 366 pages -= range; 367 } 368 369 return err; 370 } 371 372 /* ------------------------------------------------------------------ */ 373 374 static void gntdev_vma_open(struct vm_area_struct *vma) 375 { 376 struct grant_map *map = vma->vm_private_data; 377 378 pr_debug("gntdev_vma_open %p\n", vma); 379 atomic_inc(&map->users); 380 } 381 382 static void gntdev_vma_close(struct vm_area_struct *vma) 383 { 384 struct grant_map *map = vma->vm_private_data; 385 struct file *file = vma->vm_file; 386 struct gntdev_priv *priv = file->private_data; 387 388 pr_debug("gntdev_vma_close %p\n", vma); 389 if (use_ptemod) { 390 /* It is possible that an mmu notifier could be running 391 * concurrently, so take priv->lock to ensure that the vma won't 392 * vanishing during the unmap_grant_pages call, since we will 393 * spin here until that completes. Such a concurrent call will 394 * not do any unmapping, since that has been done prior to 395 * closing the vma, but it may still iterate the unmap_ops list. 396 */ 397 spin_lock(&priv->lock); 398 map->vma = NULL; 399 spin_unlock(&priv->lock); 400 } 401 vma->vm_private_data = NULL; 402 gntdev_put_map(priv, map); 403 } 404 405 static struct vm_operations_struct gntdev_vmops = { 406 .open = gntdev_vma_open, 407 .close = gntdev_vma_close, 408 }; 409 410 /* ------------------------------------------------------------------ */ 411 412 static void unmap_if_in_range(struct grant_map *map, 413 unsigned long start, unsigned long end) 414 { 415 unsigned long mstart, mend; 416 int err; 417 418 if (!map->vma) 419 return; 420 if (map->vma->vm_start >= end) 421 return; 422 if (map->vma->vm_end <= start) 423 return; 424 mstart = max(start, map->vma->vm_start); 425 mend = min(end, map->vma->vm_end); 426 pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n", 427 map->index, map->count, 428 map->vma->vm_start, map->vma->vm_end, 429 start, end, mstart, mend); 430 err = unmap_grant_pages(map, 431 (mstart - map->vma->vm_start) >> PAGE_SHIFT, 432 (mend - mstart) >> PAGE_SHIFT); 433 WARN_ON(err); 434 } 435 436 static void mn_invl_range_start(struct mmu_notifier *mn, 437 struct mm_struct *mm, 438 unsigned long start, unsigned long end) 439 { 440 struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn); 441 struct grant_map *map; 442 443 spin_lock(&priv->lock); 444 list_for_each_entry(map, &priv->maps, next) { 445 unmap_if_in_range(map, start, end); 446 } 447 list_for_each_entry(map, &priv->freeable_maps, next) { 448 unmap_if_in_range(map, start, end); 449 } 450 spin_unlock(&priv->lock); 451 } 452 453 static void mn_invl_page(struct mmu_notifier *mn, 454 struct mm_struct *mm, 455 unsigned long address) 456 { 457 mn_invl_range_start(mn, mm, address, address + PAGE_SIZE); 458 } 459 460 static void mn_release(struct mmu_notifier *mn, 461 struct mm_struct *mm) 462 { 463 struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn); 464 struct grant_map *map; 465 int err; 466 467 spin_lock(&priv->lock); 468 list_for_each_entry(map, &priv->maps, next) { 469 if (!map->vma) 470 continue; 471 pr_debug("map %d+%d (%lx %lx)\n", 472 map->index, map->count, 473 map->vma->vm_start, map->vma->vm_end); 474 err = unmap_grant_pages(map, /* offset */ 0, map->count); 475 WARN_ON(err); 476 } 477 list_for_each_entry(map, &priv->freeable_maps, next) { 478 if (!map->vma) 479 continue; 480 pr_debug("map %d+%d (%lx %lx)\n", 481 map->index, map->count, 482 map->vma->vm_start, map->vma->vm_end); 483 err = unmap_grant_pages(map, /* offset */ 0, map->count); 484 WARN_ON(err); 485 } 486 spin_unlock(&priv->lock); 487 } 488 489 static struct mmu_notifier_ops gntdev_mmu_ops = { 490 .release = mn_release, 491 .invalidate_page = mn_invl_page, 492 .invalidate_range_start = mn_invl_range_start, 493 }; 494 495 /* ------------------------------------------------------------------ */ 496 497 static int gntdev_open(struct inode *inode, struct file *flip) 498 { 499 struct gntdev_priv *priv; 500 int ret = 0; 501 502 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 503 if (!priv) 504 return -ENOMEM; 505 506 INIT_LIST_HEAD(&priv->maps); 507 INIT_LIST_HEAD(&priv->freeable_maps); 508 spin_lock_init(&priv->lock); 509 510 if (use_ptemod) { 511 priv->mm = get_task_mm(current); 512 if (!priv->mm) { 513 kfree(priv); 514 return -ENOMEM; 515 } 516 priv->mn.ops = &gntdev_mmu_ops; 517 ret = mmu_notifier_register(&priv->mn, priv->mm); 518 mmput(priv->mm); 519 } 520 521 if (ret) { 522 kfree(priv); 523 return ret; 524 } 525 526 flip->private_data = priv; 527 pr_debug("priv %p\n", priv); 528 529 return 0; 530 } 531 532 static int gntdev_release(struct inode *inode, struct file *flip) 533 { 534 struct gntdev_priv *priv = flip->private_data; 535 struct grant_map *map; 536 537 pr_debug("priv %p\n", priv); 538 539 while (!list_empty(&priv->maps)) { 540 map = list_entry(priv->maps.next, struct grant_map, next); 541 list_del(&map->next); 542 gntdev_put_map(NULL /* already removed */, map); 543 } 544 WARN_ON(!list_empty(&priv->freeable_maps)); 545 546 if (use_ptemod) 547 mmu_notifier_unregister(&priv->mn, priv->mm); 548 kfree(priv); 549 return 0; 550 } 551 552 static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv, 553 struct ioctl_gntdev_map_grant_ref __user *u) 554 { 555 struct ioctl_gntdev_map_grant_ref op; 556 struct grant_map *map; 557 int err; 558 559 if (copy_from_user(&op, u, sizeof(op)) != 0) 560 return -EFAULT; 561 pr_debug("priv %p, add %d\n", priv, op.count); 562 if (unlikely(op.count <= 0)) 563 return -EINVAL; 564 565 err = -ENOMEM; 566 map = gntdev_alloc_map(priv, op.count); 567 if (!map) 568 return err; 569 570 if (unlikely(atomic_add_return(op.count, &pages_mapped) > limit)) { 571 pr_debug("can't map: over limit\n"); 572 gntdev_put_map(NULL, map); 573 return err; 574 } 575 576 if (copy_from_user(map->grants, &u->refs, 577 sizeof(map->grants[0]) * op.count) != 0) { 578 gntdev_put_map(NULL, map); 579 return -EFAULT; 580 } 581 582 spin_lock(&priv->lock); 583 gntdev_add_map(priv, map); 584 op.index = map->index << PAGE_SHIFT; 585 spin_unlock(&priv->lock); 586 587 if (copy_to_user(u, &op, sizeof(op)) != 0) 588 return -EFAULT; 589 590 return 0; 591 } 592 593 static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv, 594 struct ioctl_gntdev_unmap_grant_ref __user *u) 595 { 596 struct ioctl_gntdev_unmap_grant_ref op; 597 struct grant_map *map; 598 int err = -ENOENT; 599 600 if (copy_from_user(&op, u, sizeof(op)) != 0) 601 return -EFAULT; 602 pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count); 603 604 spin_lock(&priv->lock); 605 map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count); 606 if (map) { 607 list_del(&map->next); 608 if (populate_freeable_maps) 609 list_add_tail(&map->next, &priv->freeable_maps); 610 err = 0; 611 } 612 spin_unlock(&priv->lock); 613 if (map) 614 gntdev_put_map(priv, map); 615 return err; 616 } 617 618 static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv, 619 struct ioctl_gntdev_get_offset_for_vaddr __user *u) 620 { 621 struct ioctl_gntdev_get_offset_for_vaddr op; 622 struct vm_area_struct *vma; 623 struct grant_map *map; 624 int rv = -EINVAL; 625 626 if (copy_from_user(&op, u, sizeof(op)) != 0) 627 return -EFAULT; 628 pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr); 629 630 down_read(¤t->mm->mmap_sem); 631 vma = find_vma(current->mm, op.vaddr); 632 if (!vma || vma->vm_ops != &gntdev_vmops) 633 goto out_unlock; 634 635 map = vma->vm_private_data; 636 if (!map) 637 goto out_unlock; 638 639 op.offset = map->index << PAGE_SHIFT; 640 op.count = map->count; 641 rv = 0; 642 643 out_unlock: 644 up_read(¤t->mm->mmap_sem); 645 646 if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0) 647 return -EFAULT; 648 return rv; 649 } 650 651 static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u) 652 { 653 struct ioctl_gntdev_unmap_notify op; 654 struct grant_map *map; 655 int rc; 656 int out_flags; 657 unsigned int out_event; 658 659 if (copy_from_user(&op, u, sizeof(op))) 660 return -EFAULT; 661 662 if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT)) 663 return -EINVAL; 664 665 /* We need to grab a reference to the event channel we are going to use 666 * to send the notify before releasing the reference we may already have 667 * (if someone has called this ioctl twice). This is required so that 668 * it is possible to change the clear_byte part of the notification 669 * without disturbing the event channel part, which may now be the last 670 * reference to that event channel. 671 */ 672 if (op.action & UNMAP_NOTIFY_SEND_EVENT) { 673 if (evtchn_get(op.event_channel_port)) 674 return -EINVAL; 675 } 676 677 out_flags = op.action; 678 out_event = op.event_channel_port; 679 680 spin_lock(&priv->lock); 681 682 list_for_each_entry(map, &priv->maps, next) { 683 uint64_t begin = map->index << PAGE_SHIFT; 684 uint64_t end = (map->index + map->count) << PAGE_SHIFT; 685 if (op.index >= begin && op.index < end) 686 goto found; 687 } 688 rc = -ENOENT; 689 goto unlock_out; 690 691 found: 692 if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) && 693 (map->flags & GNTMAP_readonly)) { 694 rc = -EINVAL; 695 goto unlock_out; 696 } 697 698 out_flags = map->notify.flags; 699 out_event = map->notify.event; 700 701 map->notify.flags = op.action; 702 map->notify.addr = op.index - (map->index << PAGE_SHIFT); 703 map->notify.event = op.event_channel_port; 704 705 rc = 0; 706 707 unlock_out: 708 spin_unlock(&priv->lock); 709 710 /* Drop the reference to the event channel we did not save in the map */ 711 if (out_flags & UNMAP_NOTIFY_SEND_EVENT) 712 evtchn_put(out_event); 713 714 return rc; 715 } 716 717 static long gntdev_ioctl(struct file *flip, 718 unsigned int cmd, unsigned long arg) 719 { 720 struct gntdev_priv *priv = flip->private_data; 721 void __user *ptr = (void __user *)arg; 722 723 switch (cmd) { 724 case IOCTL_GNTDEV_MAP_GRANT_REF: 725 return gntdev_ioctl_map_grant_ref(priv, ptr); 726 727 case IOCTL_GNTDEV_UNMAP_GRANT_REF: 728 return gntdev_ioctl_unmap_grant_ref(priv, ptr); 729 730 case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR: 731 return gntdev_ioctl_get_offset_for_vaddr(priv, ptr); 732 733 case IOCTL_GNTDEV_SET_UNMAP_NOTIFY: 734 return gntdev_ioctl_notify(priv, ptr); 735 736 default: 737 pr_debug("priv %p, unknown cmd %x\n", priv, cmd); 738 return -ENOIOCTLCMD; 739 } 740 741 return 0; 742 } 743 744 static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) 745 { 746 struct gntdev_priv *priv = flip->private_data; 747 int index = vma->vm_pgoff; 748 int count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; 749 struct grant_map *map; 750 int i, err = -EINVAL; 751 752 if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED)) 753 return -EINVAL; 754 755 pr_debug("map %d+%d at %lx (pgoff %lx)\n", 756 index, count, vma->vm_start, vma->vm_pgoff); 757 758 spin_lock(&priv->lock); 759 map = gntdev_find_map_index(priv, index, count); 760 if (!map) 761 goto unlock_out; 762 if (use_ptemod && map->vma) 763 goto unlock_out; 764 if (use_ptemod && priv->mm != vma->vm_mm) { 765 pr_warn("Huh? Other mm?\n"); 766 goto unlock_out; 767 } 768 769 atomic_inc(&map->users); 770 771 vma->vm_ops = &gntdev_vmops; 772 773 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; 774 775 if (use_ptemod) 776 vma->vm_flags |= VM_DONTCOPY; 777 778 vma->vm_private_data = map; 779 780 if (use_ptemod) 781 map->vma = vma; 782 783 if (map->flags) { 784 if ((vma->vm_flags & VM_WRITE) && 785 (map->flags & GNTMAP_readonly)) 786 goto out_unlock_put; 787 } else { 788 map->flags = GNTMAP_host_map; 789 if (!(vma->vm_flags & VM_WRITE)) 790 map->flags |= GNTMAP_readonly; 791 } 792 793 spin_unlock(&priv->lock); 794 795 if (use_ptemod) { 796 err = apply_to_page_range(vma->vm_mm, vma->vm_start, 797 vma->vm_end - vma->vm_start, 798 find_grant_ptes, map); 799 if (err) { 800 pr_warn("find_grant_ptes() failure.\n"); 801 goto out_put_map; 802 } 803 } 804 805 err = map_grant_pages(map); 806 if (err) 807 goto out_put_map; 808 809 if (!use_ptemod) { 810 for (i = 0; i < count; i++) { 811 err = vm_insert_page(vma, vma->vm_start + i*PAGE_SIZE, 812 map->pages[i]); 813 if (err) 814 goto out_put_map; 815 } 816 } 817 818 return 0; 819 820 unlock_out: 821 spin_unlock(&priv->lock); 822 return err; 823 824 out_unlock_put: 825 spin_unlock(&priv->lock); 826 out_put_map: 827 if (use_ptemod) 828 map->vma = NULL; 829 gntdev_put_map(priv, map); 830 return err; 831 } 832 833 static const struct file_operations gntdev_fops = { 834 .owner = THIS_MODULE, 835 .open = gntdev_open, 836 .release = gntdev_release, 837 .mmap = gntdev_mmap, 838 .unlocked_ioctl = gntdev_ioctl 839 }; 840 841 static struct miscdevice gntdev_miscdev = { 842 .minor = MISC_DYNAMIC_MINOR, 843 .name = "xen/gntdev", 844 .fops = &gntdev_fops, 845 }; 846 847 /* ------------------------------------------------------------------ */ 848 849 static int __init gntdev_init(void) 850 { 851 int err; 852 853 if (!xen_domain()) 854 return -ENODEV; 855 856 use_ptemod = xen_pv_domain(); 857 858 err = misc_register(&gntdev_miscdev); 859 if (err != 0) { 860 pr_err("Could not register gntdev device\n"); 861 return err; 862 } 863 return 0; 864 } 865 866 static void __exit gntdev_exit(void) 867 { 868 misc_deregister(&gntdev_miscdev); 869 } 870 871 module_init(gntdev_init); 872 module_exit(gntdev_exit); 873 874 /* ------------------------------------------------------------------ */ 875