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 48MODULE_LICENSE("GPL"); 49MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, " 50 "Gerd Hoffmann <kraxel@redhat.com>"); 51MODULE_DESCRIPTION("User-space granted page access driver"); 52 53static int limit = 1024*1024; 54module_param(limit, int, 0644); 55MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped by " 56 "the gntdev device"); 57 58static atomic_t pages_mapped = ATOMIC_INIT(0); 59 60static int use_ptemod; 61#define populate_freeable_maps use_ptemod 62 63struct 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 75struct unmap_notify { 76 int flags; 77 /* Address relative to the start of the grant_map */ 78 int addr; 79 int event; 80}; 81 82struct 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 97static int unmap_grant_pages(struct grant_map *map, int offset, int pages); 98 99/* ------------------------------------------------------------------ */ 100 101static 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 115static 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 130static 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 166err: 167 gntdev_free_map(add); 168 return NULL; 169} 170 171static 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 184done: 185 gntdev_print_maps(priv, "[new]", add->index); 186} 187 188static 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 203static 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 231static 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 250static 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(map->map_ops, use_ptemod ? map->kmap_ops : NULL, 288 map->pages, map->count); 289 if (err) 290 return err; 291 292 for (i = 0; i < map->count; i++) { 293 if (map->map_ops[i].status) 294 err = -EINVAL; 295 else { 296 BUG_ON(map->map_ops[i].handle == -1); 297 map->unmap_ops[i].handle = map->map_ops[i].handle; 298 pr_debug("map handle=%d\n", map->map_ops[i].handle); 299 } 300 } 301 return err; 302} 303 304static int __unmap_grant_pages(struct grant_map *map, int offset, int pages) 305{ 306 int i, err = 0; 307 308 if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) { 309 int pgno = (map->notify.addr >> PAGE_SHIFT); 310 if (pgno >= offset && pgno < offset + pages) { 311 /* No need for kmap, pages are in lowmem */ 312 uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno])); 313 tmp[map->notify.addr & (PAGE_SIZE-1)] = 0; 314 map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE; 315 } 316 } 317 318 err = gnttab_unmap_refs(map->unmap_ops + offset, 319 use_ptemod ? map->kmap_ops + offset : NULL, map->pages + offset, 320 pages); 321 if (err) 322 return err; 323 324 for (i = 0; i < pages; i++) { 325 if (map->unmap_ops[offset+i].status) 326 err = -EINVAL; 327 pr_debug("unmap handle=%d st=%d\n", 328 map->unmap_ops[offset+i].handle, 329 map->unmap_ops[offset+i].status); 330 map->unmap_ops[offset+i].handle = -1; 331 } 332 return err; 333} 334 335static int unmap_grant_pages(struct grant_map *map, int offset, int pages) 336{ 337 int range, err = 0; 338 339 pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages); 340 341 /* It is possible the requested range will have a "hole" where we 342 * already unmapped some of the grants. Only unmap valid ranges. 343 */ 344 while (pages && !err) { 345 while (pages && map->unmap_ops[offset].handle == -1) { 346 offset++; 347 pages--; 348 } 349 range = 0; 350 while (range < pages) { 351 if (map->unmap_ops[offset+range].handle == -1) { 352 range--; 353 break; 354 } 355 range++; 356 } 357 err = __unmap_grant_pages(map, offset, range); 358 offset += range; 359 pages -= range; 360 } 361 362 return err; 363} 364 365/* ------------------------------------------------------------------ */ 366 367static void gntdev_vma_open(struct vm_area_struct *vma) 368{ 369 struct grant_map *map = vma->vm_private_data; 370 371 pr_debug("gntdev_vma_open %p\n", vma); 372 atomic_inc(&map->users); 373} 374 375static void gntdev_vma_close(struct vm_area_struct *vma) 376{ 377 struct grant_map *map = vma->vm_private_data; 378 struct file *file = vma->vm_file; 379 struct gntdev_priv *priv = file->private_data; 380 381 pr_debug("gntdev_vma_close %p\n", vma); 382 if (use_ptemod) { 383 /* It is possible that an mmu notifier could be running 384 * concurrently, so take priv->lock to ensure that the vma won't 385 * vanishing during the unmap_grant_pages call, since we will 386 * spin here until that completes. Such a concurrent call will 387 * not do any unmapping, since that has been done prior to 388 * closing the vma, but it may still iterate the unmap_ops list. 389 */ 390 spin_lock(&priv->lock); 391 map->vma = NULL; 392 spin_unlock(&priv->lock); 393 } 394 vma->vm_private_data = NULL; 395 gntdev_put_map(priv, map); 396} 397 398static struct vm_operations_struct gntdev_vmops = { 399 .open = gntdev_vma_open, 400 .close = gntdev_vma_close, 401}; 402 403/* ------------------------------------------------------------------ */ 404 405static void unmap_if_in_range(struct grant_map *map, 406 unsigned long start, unsigned long end) 407{ 408 unsigned long mstart, mend; 409 int err; 410 411 if (!map->vma) 412 return; 413 if (map->vma->vm_start >= end) 414 return; 415 if (map->vma->vm_end <= start) 416 return; 417 mstart = max(start, map->vma->vm_start); 418 mend = min(end, map->vma->vm_end); 419 pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n", 420 map->index, map->count, 421 map->vma->vm_start, map->vma->vm_end, 422 start, end, mstart, mend); 423 err = unmap_grant_pages(map, 424 (mstart - map->vma->vm_start) >> PAGE_SHIFT, 425 (mend - mstart) >> PAGE_SHIFT); 426 WARN_ON(err); 427} 428 429static void mn_invl_range_start(struct mmu_notifier *mn, 430 struct mm_struct *mm, 431 unsigned long start, unsigned long end) 432{ 433 struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn); 434 struct grant_map *map; 435 436 spin_lock(&priv->lock); 437 list_for_each_entry(map, &priv->maps, next) { 438 unmap_if_in_range(map, start, end); 439 } 440 list_for_each_entry(map, &priv->freeable_maps, next) { 441 unmap_if_in_range(map, start, end); 442 } 443 spin_unlock(&priv->lock); 444} 445 446static void mn_invl_page(struct mmu_notifier *mn, 447 struct mm_struct *mm, 448 unsigned long address) 449{ 450 mn_invl_range_start(mn, mm, address, address + PAGE_SIZE); 451} 452 453static void mn_release(struct mmu_notifier *mn, 454 struct mm_struct *mm) 455{ 456 struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn); 457 struct grant_map *map; 458 int err; 459 460 spin_lock(&priv->lock); 461 list_for_each_entry(map, &priv->maps, next) { 462 if (!map->vma) 463 continue; 464 pr_debug("map %d+%d (%lx %lx)\n", 465 map->index, map->count, 466 map->vma->vm_start, map->vma->vm_end); 467 err = unmap_grant_pages(map, /* offset */ 0, map->count); 468 WARN_ON(err); 469 } 470 list_for_each_entry(map, &priv->freeable_maps, next) { 471 if (!map->vma) 472 continue; 473 pr_debug("map %d+%d (%lx %lx)\n", 474 map->index, map->count, 475 map->vma->vm_start, map->vma->vm_end); 476 err = unmap_grant_pages(map, /* offset */ 0, map->count); 477 WARN_ON(err); 478 } 479 spin_unlock(&priv->lock); 480} 481 482static struct mmu_notifier_ops gntdev_mmu_ops = { 483 .release = mn_release, 484 .invalidate_page = mn_invl_page, 485 .invalidate_range_start = mn_invl_range_start, 486}; 487 488/* ------------------------------------------------------------------ */ 489 490static int gntdev_open(struct inode *inode, struct file *flip) 491{ 492 struct gntdev_priv *priv; 493 int ret = 0; 494 495 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 496 if (!priv) 497 return -ENOMEM; 498 499 INIT_LIST_HEAD(&priv->maps); 500 INIT_LIST_HEAD(&priv->freeable_maps); 501 spin_lock_init(&priv->lock); 502 503 if (use_ptemod) { 504 priv->mm = get_task_mm(current); 505 if (!priv->mm) { 506 kfree(priv); 507 return -ENOMEM; 508 } 509 priv->mn.ops = &gntdev_mmu_ops; 510 ret = mmu_notifier_register(&priv->mn, priv->mm); 511 mmput(priv->mm); 512 } 513 514 if (ret) { 515 kfree(priv); 516 return ret; 517 } 518 519 flip->private_data = priv; 520 pr_debug("priv %p\n", priv); 521 522 return 0; 523} 524 525static int gntdev_release(struct inode *inode, struct file *flip) 526{ 527 struct gntdev_priv *priv = flip->private_data; 528 struct grant_map *map; 529 530 pr_debug("priv %p\n", priv); 531 532 while (!list_empty(&priv->maps)) { 533 map = list_entry(priv->maps.next, struct grant_map, next); 534 list_del(&map->next); 535 gntdev_put_map(NULL /* already removed */, map); 536 } 537 WARN_ON(!list_empty(&priv->freeable_maps)); 538 539 if (use_ptemod) 540 mmu_notifier_unregister(&priv->mn, priv->mm); 541 kfree(priv); 542 return 0; 543} 544 545static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv, 546 struct ioctl_gntdev_map_grant_ref __user *u) 547{ 548 struct ioctl_gntdev_map_grant_ref op; 549 struct grant_map *map; 550 int err; 551 552 if (copy_from_user(&op, u, sizeof(op)) != 0) 553 return -EFAULT; 554 pr_debug("priv %p, add %d\n", priv, op.count); 555 if (unlikely(op.count <= 0)) 556 return -EINVAL; 557 558 err = -ENOMEM; 559 map = gntdev_alloc_map(priv, op.count); 560 if (!map) 561 return err; 562 563 if (unlikely(atomic_add_return(op.count, &pages_mapped) > limit)) { 564 pr_debug("can't map: over limit\n"); 565 gntdev_put_map(NULL, map); 566 return err; 567 } 568 569 if (copy_from_user(map->grants, &u->refs, 570 sizeof(map->grants[0]) * op.count) != 0) { 571 gntdev_put_map(NULL, map); 572 return -EFAULT; 573 } 574 575 spin_lock(&priv->lock); 576 gntdev_add_map(priv, map); 577 op.index = map->index << PAGE_SHIFT; 578 spin_unlock(&priv->lock); 579 580 if (copy_to_user(u, &op, sizeof(op)) != 0) 581 return -EFAULT; 582 583 return 0; 584} 585 586static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv, 587 struct ioctl_gntdev_unmap_grant_ref __user *u) 588{ 589 struct ioctl_gntdev_unmap_grant_ref op; 590 struct grant_map *map; 591 int err = -ENOENT; 592 593 if (copy_from_user(&op, u, sizeof(op)) != 0) 594 return -EFAULT; 595 pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count); 596 597 spin_lock(&priv->lock); 598 map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count); 599 if (map) { 600 list_del(&map->next); 601 if (populate_freeable_maps) 602 list_add_tail(&map->next, &priv->freeable_maps); 603 err = 0; 604 } 605 spin_unlock(&priv->lock); 606 if (map) 607 gntdev_put_map(priv, map); 608 return err; 609} 610 611static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv, 612 struct ioctl_gntdev_get_offset_for_vaddr __user *u) 613{ 614 struct ioctl_gntdev_get_offset_for_vaddr op; 615 struct vm_area_struct *vma; 616 struct grant_map *map; 617 int rv = -EINVAL; 618 619 if (copy_from_user(&op, u, sizeof(op)) != 0) 620 return -EFAULT; 621 pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr); 622 623 down_read(¤t->mm->mmap_sem); 624 vma = find_vma(current->mm, op.vaddr); 625 if (!vma || vma->vm_ops != &gntdev_vmops) 626 goto out_unlock; 627 628 map = vma->vm_private_data; 629 if (!map) 630 goto out_unlock; 631 632 op.offset = map->index << PAGE_SHIFT; 633 op.count = map->count; 634 rv = 0; 635 636 out_unlock: 637 up_read(¤t->mm->mmap_sem); 638 639 if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0) 640 return -EFAULT; 641 return rv; 642} 643 644static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u) 645{ 646 struct ioctl_gntdev_unmap_notify op; 647 struct grant_map *map; 648 int rc; 649 int out_flags; 650 unsigned int out_event; 651 652 if (copy_from_user(&op, u, sizeof(op))) 653 return -EFAULT; 654 655 if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT)) 656 return -EINVAL; 657 658 /* We need to grab a reference to the event channel we are going to use 659 * to send the notify before releasing the reference we may already have 660 * (if someone has called this ioctl twice). This is required so that 661 * it is possible to change the clear_byte part of the notification 662 * without disturbing the event channel part, which may now be the last 663 * reference to that event channel. 664 */ 665 if (op.action & UNMAP_NOTIFY_SEND_EVENT) { 666 if (evtchn_get(op.event_channel_port)) 667 return -EINVAL; 668 } 669 670 out_flags = op.action; 671 out_event = op.event_channel_port; 672 673 spin_lock(&priv->lock); 674 675 list_for_each_entry(map, &priv->maps, next) { 676 uint64_t begin = map->index << PAGE_SHIFT; 677 uint64_t end = (map->index + map->count) << PAGE_SHIFT; 678 if (op.index >= begin && op.index < end) 679 goto found; 680 } 681 rc = -ENOENT; 682 goto unlock_out; 683 684 found: 685 if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) && 686 (map->flags & GNTMAP_readonly)) { 687 rc = -EINVAL; 688 goto unlock_out; 689 } 690 691 out_flags = map->notify.flags; 692 out_event = map->notify.event; 693 694 map->notify.flags = op.action; 695 map->notify.addr = op.index - (map->index << PAGE_SHIFT); 696 map->notify.event = op.event_channel_port; 697 698 rc = 0; 699 700 unlock_out: 701 spin_unlock(&priv->lock); 702 703 /* Drop the reference to the event channel we did not save in the map */ 704 if (out_flags & UNMAP_NOTIFY_SEND_EVENT) 705 evtchn_put(out_event); 706 707 return rc; 708} 709 710static long gntdev_ioctl(struct file *flip, 711 unsigned int cmd, unsigned long arg) 712{ 713 struct gntdev_priv *priv = flip->private_data; 714 void __user *ptr = (void __user *)arg; 715 716 switch (cmd) { 717 case IOCTL_GNTDEV_MAP_GRANT_REF: 718 return gntdev_ioctl_map_grant_ref(priv, ptr); 719 720 case IOCTL_GNTDEV_UNMAP_GRANT_REF: 721 return gntdev_ioctl_unmap_grant_ref(priv, ptr); 722 723 case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR: 724 return gntdev_ioctl_get_offset_for_vaddr(priv, ptr); 725 726 case IOCTL_GNTDEV_SET_UNMAP_NOTIFY: 727 return gntdev_ioctl_notify(priv, ptr); 728 729 default: 730 pr_debug("priv %p, unknown cmd %x\n", priv, cmd); 731 return -ENOIOCTLCMD; 732 } 733 734 return 0; 735} 736 737static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) 738{ 739 struct gntdev_priv *priv = flip->private_data; 740 int index = vma->vm_pgoff; 741 int count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; 742 struct grant_map *map; 743 int i, err = -EINVAL; 744 745 if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED)) 746 return -EINVAL; 747 748 pr_debug("map %d+%d at %lx (pgoff %lx)\n", 749 index, count, vma->vm_start, vma->vm_pgoff); 750 751 spin_lock(&priv->lock); 752 map = gntdev_find_map_index(priv, index, count); 753 if (!map) 754 goto unlock_out; 755 if (use_ptemod && map->vma) 756 goto unlock_out; 757 if (use_ptemod && priv->mm != vma->vm_mm) { 758 pr_warn("Huh? Other mm?\n"); 759 goto unlock_out; 760 } 761 762 atomic_inc(&map->users); 763 764 vma->vm_ops = &gntdev_vmops; 765 766 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; 767 768 if (use_ptemod) 769 vma->vm_flags |= VM_DONTCOPY; 770 771 vma->vm_private_data = map; 772 773 if (use_ptemod) 774 map->vma = vma; 775 776 if (map->flags) { 777 if ((vma->vm_flags & VM_WRITE) && 778 (map->flags & GNTMAP_readonly)) 779 goto out_unlock_put; 780 } else { 781 map->flags = GNTMAP_host_map; 782 if (!(vma->vm_flags & VM_WRITE)) 783 map->flags |= GNTMAP_readonly; 784 } 785 786 spin_unlock(&priv->lock); 787 788 if (use_ptemod) { 789 err = apply_to_page_range(vma->vm_mm, vma->vm_start, 790 vma->vm_end - vma->vm_start, 791 find_grant_ptes, map); 792 if (err) { 793 pr_warn("find_grant_ptes() failure.\n"); 794 goto out_put_map; 795 } 796 } 797 798 err = map_grant_pages(map); 799 if (err) 800 goto out_put_map; 801 802 if (!use_ptemod) { 803 for (i = 0; i < count; i++) { 804 err = vm_insert_page(vma, vma->vm_start + i*PAGE_SIZE, 805 map->pages[i]); 806 if (err) 807 goto out_put_map; 808 } 809 } 810 811 return 0; 812 813unlock_out: 814 spin_unlock(&priv->lock); 815 return err; 816 817out_unlock_put: 818 spin_unlock(&priv->lock); 819out_put_map: 820 if (use_ptemod) 821 map->vma = NULL; 822 gntdev_put_map(priv, map); 823 return err; 824} 825 826static const struct file_operations gntdev_fops = { 827 .owner = THIS_MODULE, 828 .open = gntdev_open, 829 .release = gntdev_release, 830 .mmap = gntdev_mmap, 831 .unlocked_ioctl = gntdev_ioctl 832}; 833 834static struct miscdevice gntdev_miscdev = { 835 .minor = MISC_DYNAMIC_MINOR, 836 .name = "xen/gntdev", 837 .fops = &gntdev_fops, 838}; 839 840/* ------------------------------------------------------------------ */ 841 842static int __init gntdev_init(void) 843{ 844 int err; 845 846 if (!xen_domain()) 847 return -ENODEV; 848 849 use_ptemod = !xen_feature(XENFEAT_auto_translated_physmap); 850 851 err = misc_register(&gntdev_miscdev); 852 if (err != 0) { 853 pr_err("Could not register gntdev device\n"); 854 return err; 855 } 856 return 0; 857} 858 859static void __exit gntdev_exit(void) 860{ 861 misc_deregister(&gntdev_miscdev); 862} 863 864module_init(gntdev_init); 865module_exit(gntdev_exit); 866 867/* ------------------------------------------------------------------ */ 868