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