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