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