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 * (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 19 */ 20 21 #undef DEBUG 22 23 #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt 24 25 #include <linux/dma-mapping.h> 26 #include <linux/module.h> 27 #include <linux/kernel.h> 28 #include <linux/init.h> 29 #include <linux/miscdevice.h> 30 #include <linux/fs.h> 31 #include <linux/uaccess.h> 32 #include <linux/sched.h> 33 #include <linux/sched/mm.h> 34 #include <linux/spinlock.h> 35 #include <linux/slab.h> 36 #include <linux/highmem.h> 37 #include <linux/refcount.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 <xen/page.h> 45 #include <asm/xen/hypervisor.h> 46 #include <asm/xen/hypercall.h> 47 48 #include "gntdev-common.h" 49 #ifdef CONFIG_XEN_GNTDEV_DMABUF 50 #include "gntdev-dmabuf.h" 51 #endif 52 53 MODULE_LICENSE("GPL"); 54 MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, " 55 "Gerd Hoffmann <kraxel@redhat.com>"); 56 MODULE_DESCRIPTION("User-space granted page access driver"); 57 58 static unsigned int limit = 64*1024; 59 module_param(limit, uint, 0644); 60 MODULE_PARM_DESC(limit, 61 "Maximum number of grants that may be mapped by one mapping request"); 62 63 static int use_ptemod; 64 65 static int unmap_grant_pages(struct gntdev_grant_map *map, 66 int offset, int pages); 67 68 static struct miscdevice gntdev_miscdev; 69 70 /* ------------------------------------------------------------------ */ 71 72 bool gntdev_test_page_count(unsigned int count) 73 { 74 return !count || count > limit; 75 } 76 77 static void gntdev_print_maps(struct gntdev_priv *priv, 78 char *text, int text_index) 79 { 80 #ifdef DEBUG 81 struct gntdev_grant_map *map; 82 83 pr_debug("%s: maps list (priv %p)\n", __func__, priv); 84 list_for_each_entry(map, &priv->maps, next) 85 pr_debug(" index %2d, count %2d %s\n", 86 map->index, map->count, 87 map->index == text_index && text ? text : ""); 88 #endif 89 } 90 91 static void gntdev_free_map(struct gntdev_grant_map *map) 92 { 93 if (map == NULL) 94 return; 95 96 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC 97 if (map->dma_vaddr) { 98 struct gnttab_dma_alloc_args args; 99 100 args.dev = map->dma_dev; 101 args.coherent = !!(map->dma_flags & GNTDEV_DMA_FLAG_COHERENT); 102 args.nr_pages = map->count; 103 args.pages = map->pages; 104 args.frames = map->frames; 105 args.vaddr = map->dma_vaddr; 106 args.dev_bus_addr = map->dma_bus_addr; 107 108 gnttab_dma_free_pages(&args); 109 } else 110 #endif 111 if (map->pages) 112 gnttab_free_pages(map->count, map->pages); 113 114 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC 115 kvfree(map->frames); 116 #endif 117 kvfree(map->pages); 118 kvfree(map->grants); 119 kvfree(map->map_ops); 120 kvfree(map->unmap_ops); 121 kvfree(map->kmap_ops); 122 kvfree(map->kunmap_ops); 123 kfree(map); 124 } 125 126 struct gntdev_grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count, 127 int dma_flags) 128 { 129 struct gntdev_grant_map *add; 130 int i; 131 132 add = kzalloc(sizeof(*add), GFP_KERNEL); 133 if (NULL == add) 134 return NULL; 135 136 add->grants = kvmalloc_array(count, sizeof(add->grants[0]), 137 GFP_KERNEL); 138 add->map_ops = kvmalloc_array(count, sizeof(add->map_ops[0]), 139 GFP_KERNEL); 140 add->unmap_ops = kvmalloc_array(count, sizeof(add->unmap_ops[0]), 141 GFP_KERNEL); 142 add->pages = kvcalloc(count, sizeof(add->pages[0]), GFP_KERNEL); 143 if (NULL == add->grants || 144 NULL == add->map_ops || 145 NULL == add->unmap_ops || 146 NULL == add->pages) 147 goto err; 148 if (use_ptemod) { 149 add->kmap_ops = kvmalloc_array(count, sizeof(add->kmap_ops[0]), 150 GFP_KERNEL); 151 add->kunmap_ops = kvmalloc_array(count, sizeof(add->kunmap_ops[0]), 152 GFP_KERNEL); 153 if (NULL == add->kmap_ops || NULL == add->kunmap_ops) 154 goto err; 155 } 156 157 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC 158 add->dma_flags = dma_flags; 159 160 /* 161 * Check if this mapping is requested to be backed 162 * by a DMA buffer. 163 */ 164 if (dma_flags & (GNTDEV_DMA_FLAG_WC | GNTDEV_DMA_FLAG_COHERENT)) { 165 struct gnttab_dma_alloc_args args; 166 167 add->frames = kvcalloc(count, sizeof(add->frames[0]), 168 GFP_KERNEL); 169 if (!add->frames) 170 goto err; 171 172 /* Remember the device, so we can free DMA memory. */ 173 add->dma_dev = priv->dma_dev; 174 175 args.dev = priv->dma_dev; 176 args.coherent = !!(dma_flags & GNTDEV_DMA_FLAG_COHERENT); 177 args.nr_pages = count; 178 args.pages = add->pages; 179 args.frames = add->frames; 180 181 if (gnttab_dma_alloc_pages(&args)) 182 goto err; 183 184 add->dma_vaddr = args.vaddr; 185 add->dma_bus_addr = args.dev_bus_addr; 186 } else 187 #endif 188 if (gnttab_alloc_pages(count, add->pages)) 189 goto err; 190 191 for (i = 0; i < count; i++) { 192 add->grants[i].domid = DOMID_INVALID; 193 add->grants[i].ref = INVALID_GRANT_REF; 194 add->map_ops[i].handle = INVALID_GRANT_HANDLE; 195 add->unmap_ops[i].handle = INVALID_GRANT_HANDLE; 196 if (use_ptemod) { 197 add->kmap_ops[i].handle = INVALID_GRANT_HANDLE; 198 add->kunmap_ops[i].handle = INVALID_GRANT_HANDLE; 199 } 200 } 201 202 add->index = 0; 203 add->count = count; 204 refcount_set(&add->users, 1); 205 206 return add; 207 208 err: 209 gntdev_free_map(add); 210 return NULL; 211 } 212 213 void gntdev_add_map(struct gntdev_priv *priv, struct gntdev_grant_map *add) 214 { 215 struct gntdev_grant_map *map; 216 217 list_for_each_entry(map, &priv->maps, next) { 218 if (add->index + add->count < map->index) { 219 list_add_tail(&add->next, &map->next); 220 goto done; 221 } 222 add->index = map->index + map->count; 223 } 224 list_add_tail(&add->next, &priv->maps); 225 226 done: 227 gntdev_print_maps(priv, "[new]", add->index); 228 } 229 230 static struct gntdev_grant_map *gntdev_find_map_index(struct gntdev_priv *priv, 231 int index, int count) 232 { 233 struct gntdev_grant_map *map; 234 235 list_for_each_entry(map, &priv->maps, next) { 236 if (map->index != index) 237 continue; 238 if (count && map->count != count) 239 continue; 240 return map; 241 } 242 return NULL; 243 } 244 245 void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map) 246 { 247 if (!map) 248 return; 249 250 if (!refcount_dec_and_test(&map->users)) 251 return; 252 253 if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) { 254 notify_remote_via_evtchn(map->notify.event); 255 evtchn_put(map->notify.event); 256 } 257 258 if (map->pages && !use_ptemod) 259 unmap_grant_pages(map, 0, map->count); 260 gntdev_free_map(map); 261 } 262 263 /* ------------------------------------------------------------------ */ 264 265 static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data) 266 { 267 struct gntdev_grant_map *map = data; 268 unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT; 269 int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte | 270 (1 << _GNTMAP_guest_avail0); 271 u64 pte_maddr; 272 273 BUG_ON(pgnr >= map->count); 274 pte_maddr = arbitrary_virt_to_machine(pte).maddr; 275 276 gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags, 277 map->grants[pgnr].ref, 278 map->grants[pgnr].domid); 279 gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags, 280 INVALID_GRANT_HANDLE); 281 return 0; 282 } 283 284 int gntdev_map_grant_pages(struct gntdev_grant_map *map) 285 { 286 int i, err = 0; 287 288 if (!use_ptemod) { 289 /* Note: it could already be mapped */ 290 if (map->map_ops[0].handle != INVALID_GRANT_HANDLE) 291 return 0; 292 for (i = 0; i < map->count; i++) { 293 unsigned long addr = (unsigned long) 294 pfn_to_kaddr(page_to_pfn(map->pages[i])); 295 gnttab_set_map_op(&map->map_ops[i], addr, map->flags, 296 map->grants[i].ref, 297 map->grants[i].domid); 298 gnttab_set_unmap_op(&map->unmap_ops[i], addr, 299 map->flags, INVALID_GRANT_HANDLE); 300 } 301 } else { 302 /* 303 * Setup the map_ops corresponding to the pte entries pointing 304 * to the kernel linear addresses of the struct pages. 305 * These ptes are completely different from the user ptes dealt 306 * with find_grant_ptes. 307 * Note that GNTMAP_device_map isn't needed here: The 308 * dev_bus_addr output field gets consumed only from ->map_ops, 309 * and by not requesting it when mapping we also avoid needing 310 * to mirror dev_bus_addr into ->unmap_ops (and holding an extra 311 * reference to the page in the hypervisor). 312 */ 313 unsigned int flags = (map->flags & ~GNTMAP_device_map) | 314 GNTMAP_host_map; 315 316 for (i = 0; i < map->count; i++) { 317 unsigned long address = (unsigned long) 318 pfn_to_kaddr(page_to_pfn(map->pages[i])); 319 BUG_ON(PageHighMem(map->pages[i])); 320 321 gnttab_set_map_op(&map->kmap_ops[i], address, flags, 322 map->grants[i].ref, 323 map->grants[i].domid); 324 gnttab_set_unmap_op(&map->kunmap_ops[i], address, 325 flags, INVALID_GRANT_HANDLE); 326 } 327 } 328 329 pr_debug("map %d+%d\n", map->index, map->count); 330 err = gnttab_map_refs(map->map_ops, map->kmap_ops, map->pages, 331 map->count); 332 333 for (i = 0; i < map->count; i++) { 334 if (map->map_ops[i].status == GNTST_okay) 335 map->unmap_ops[i].handle = map->map_ops[i].handle; 336 else if (!err) 337 err = -EINVAL; 338 339 if (map->flags & GNTMAP_device_map) 340 map->unmap_ops[i].dev_bus_addr = map->map_ops[i].dev_bus_addr; 341 342 if (use_ptemod) { 343 if (map->kmap_ops[i].status == GNTST_okay) 344 map->kunmap_ops[i].handle = map->kmap_ops[i].handle; 345 else if (!err) 346 err = -EINVAL; 347 } 348 } 349 return err; 350 } 351 352 static int __unmap_grant_pages(struct gntdev_grant_map *map, int offset, 353 int pages) 354 { 355 int i, err = 0; 356 struct gntab_unmap_queue_data unmap_data; 357 358 if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) { 359 int pgno = (map->notify.addr >> PAGE_SHIFT); 360 if (pgno >= offset && pgno < offset + pages) { 361 /* No need for kmap, pages are in lowmem */ 362 uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno])); 363 tmp[map->notify.addr & (PAGE_SIZE-1)] = 0; 364 map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE; 365 } 366 } 367 368 unmap_data.unmap_ops = map->unmap_ops + offset; 369 unmap_data.kunmap_ops = use_ptemod ? map->kunmap_ops + offset : NULL; 370 unmap_data.pages = map->pages + offset; 371 unmap_data.count = pages; 372 373 err = gnttab_unmap_refs_sync(&unmap_data); 374 if (err) 375 return err; 376 377 for (i = 0; i < pages; i++) { 378 if (map->unmap_ops[offset+i].status) 379 err = -EINVAL; 380 pr_debug("unmap handle=%d st=%d\n", 381 map->unmap_ops[offset+i].handle, 382 map->unmap_ops[offset+i].status); 383 map->unmap_ops[offset+i].handle = INVALID_GRANT_HANDLE; 384 if (use_ptemod) { 385 if (map->kunmap_ops[offset+i].status) 386 err = -EINVAL; 387 pr_debug("kunmap handle=%u st=%d\n", 388 map->kunmap_ops[offset+i].handle, 389 map->kunmap_ops[offset+i].status); 390 map->kunmap_ops[offset+i].handle = INVALID_GRANT_HANDLE; 391 } 392 } 393 return err; 394 } 395 396 static int unmap_grant_pages(struct gntdev_grant_map *map, int offset, 397 int pages) 398 { 399 int range, err = 0; 400 401 pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages); 402 403 /* It is possible the requested range will have a "hole" where we 404 * already unmapped some of the grants. Only unmap valid ranges. 405 */ 406 while (pages && !err) { 407 while (pages && 408 map->unmap_ops[offset].handle == INVALID_GRANT_HANDLE) { 409 offset++; 410 pages--; 411 } 412 range = 0; 413 while (range < pages) { 414 if (map->unmap_ops[offset + range].handle == 415 INVALID_GRANT_HANDLE) 416 break; 417 range++; 418 } 419 err = __unmap_grant_pages(map, offset, range); 420 offset += range; 421 pages -= range; 422 } 423 424 return err; 425 } 426 427 /* ------------------------------------------------------------------ */ 428 429 static void gntdev_vma_open(struct vm_area_struct *vma) 430 { 431 struct gntdev_grant_map *map = vma->vm_private_data; 432 433 pr_debug("gntdev_vma_open %p\n", vma); 434 refcount_inc(&map->users); 435 } 436 437 static void gntdev_vma_close(struct vm_area_struct *vma) 438 { 439 struct gntdev_grant_map *map = vma->vm_private_data; 440 struct file *file = vma->vm_file; 441 struct gntdev_priv *priv = file->private_data; 442 443 pr_debug("gntdev_vma_close %p\n", vma); 444 if (use_ptemod) { 445 WARN_ON(map->vma != vma); 446 mmu_interval_notifier_remove(&map->notifier); 447 map->vma = NULL; 448 } 449 vma->vm_private_data = NULL; 450 gntdev_put_map(priv, map); 451 } 452 453 static struct page *gntdev_vma_find_special_page(struct vm_area_struct *vma, 454 unsigned long addr) 455 { 456 struct gntdev_grant_map *map = vma->vm_private_data; 457 458 return map->pages[(addr - map->pages_vm_start) >> PAGE_SHIFT]; 459 } 460 461 static const struct vm_operations_struct gntdev_vmops = { 462 .open = gntdev_vma_open, 463 .close = gntdev_vma_close, 464 .find_special_page = gntdev_vma_find_special_page, 465 }; 466 467 /* ------------------------------------------------------------------ */ 468 469 static bool gntdev_invalidate(struct mmu_interval_notifier *mn, 470 const struct mmu_notifier_range *range, 471 unsigned long cur_seq) 472 { 473 struct gntdev_grant_map *map = 474 container_of(mn, struct gntdev_grant_map, notifier); 475 unsigned long mstart, mend; 476 int err; 477 478 if (!mmu_notifier_range_blockable(range)) 479 return false; 480 481 /* 482 * If the VMA is split or otherwise changed the notifier is not 483 * updated, but we don't want to process VA's outside the modified 484 * VMA. FIXME: It would be much more understandable to just prevent 485 * modifying the VMA in the first place. 486 */ 487 if (map->vma->vm_start >= range->end || 488 map->vma->vm_end <= range->start) 489 return true; 490 491 mstart = max(range->start, map->vma->vm_start); 492 mend = min(range->end, map->vma->vm_end); 493 pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n", 494 map->index, map->count, 495 map->vma->vm_start, map->vma->vm_end, 496 range->start, range->end, mstart, mend); 497 err = unmap_grant_pages(map, 498 (mstart - map->vma->vm_start) >> PAGE_SHIFT, 499 (mend - mstart) >> PAGE_SHIFT); 500 WARN_ON(err); 501 502 return true; 503 } 504 505 static const struct mmu_interval_notifier_ops gntdev_mmu_ops = { 506 .invalidate = gntdev_invalidate, 507 }; 508 509 /* ------------------------------------------------------------------ */ 510 511 static int gntdev_open(struct inode *inode, struct file *flip) 512 { 513 struct gntdev_priv *priv; 514 515 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 516 if (!priv) 517 return -ENOMEM; 518 519 INIT_LIST_HEAD(&priv->maps); 520 mutex_init(&priv->lock); 521 522 #ifdef CONFIG_XEN_GNTDEV_DMABUF 523 priv->dmabuf_priv = gntdev_dmabuf_init(flip); 524 if (IS_ERR(priv->dmabuf_priv)) { 525 int ret = PTR_ERR(priv->dmabuf_priv); 526 527 kfree(priv); 528 return ret; 529 } 530 #endif 531 532 flip->private_data = priv; 533 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC 534 priv->dma_dev = gntdev_miscdev.this_device; 535 dma_coerce_mask_and_coherent(priv->dma_dev, DMA_BIT_MASK(64)); 536 #endif 537 pr_debug("priv %p\n", priv); 538 539 return 0; 540 } 541 542 static int gntdev_release(struct inode *inode, struct file *flip) 543 { 544 struct gntdev_priv *priv = flip->private_data; 545 struct gntdev_grant_map *map; 546 547 pr_debug("priv %p\n", priv); 548 549 mutex_lock(&priv->lock); 550 while (!list_empty(&priv->maps)) { 551 map = list_entry(priv->maps.next, 552 struct gntdev_grant_map, next); 553 list_del(&map->next); 554 gntdev_put_map(NULL /* already removed */, map); 555 } 556 mutex_unlock(&priv->lock); 557 558 #ifdef CONFIG_XEN_GNTDEV_DMABUF 559 gntdev_dmabuf_fini(priv->dmabuf_priv); 560 #endif 561 562 kfree(priv); 563 return 0; 564 } 565 566 static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv, 567 struct ioctl_gntdev_map_grant_ref __user *u) 568 { 569 struct ioctl_gntdev_map_grant_ref op; 570 struct gntdev_grant_map *map; 571 int err; 572 573 if (copy_from_user(&op, u, sizeof(op)) != 0) 574 return -EFAULT; 575 pr_debug("priv %p, add %d\n", priv, op.count); 576 if (unlikely(gntdev_test_page_count(op.count))) 577 return -EINVAL; 578 579 err = -ENOMEM; 580 map = gntdev_alloc_map(priv, op.count, 0 /* This is not a dma-buf. */); 581 if (!map) 582 return err; 583 584 if (copy_from_user(map->grants, &u->refs, 585 sizeof(map->grants[0]) * op.count) != 0) { 586 gntdev_put_map(NULL, map); 587 return -EFAULT; 588 } 589 590 mutex_lock(&priv->lock); 591 gntdev_add_map(priv, map); 592 op.index = map->index << PAGE_SHIFT; 593 mutex_unlock(&priv->lock); 594 595 if (copy_to_user(u, &op, sizeof(op)) != 0) 596 return -EFAULT; 597 598 return 0; 599 } 600 601 static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv, 602 struct ioctl_gntdev_unmap_grant_ref __user *u) 603 { 604 struct ioctl_gntdev_unmap_grant_ref op; 605 struct gntdev_grant_map *map; 606 int err = -ENOENT; 607 608 if (copy_from_user(&op, u, sizeof(op)) != 0) 609 return -EFAULT; 610 pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count); 611 612 mutex_lock(&priv->lock); 613 map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count); 614 if (map) { 615 list_del(&map->next); 616 err = 0; 617 } 618 mutex_unlock(&priv->lock); 619 if (map) 620 gntdev_put_map(priv, map); 621 return err; 622 } 623 624 static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv, 625 struct ioctl_gntdev_get_offset_for_vaddr __user *u) 626 { 627 struct ioctl_gntdev_get_offset_for_vaddr op; 628 struct vm_area_struct *vma; 629 struct gntdev_grant_map *map; 630 int rv = -EINVAL; 631 632 if (copy_from_user(&op, u, sizeof(op)) != 0) 633 return -EFAULT; 634 pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr); 635 636 mmap_read_lock(current->mm); 637 vma = find_vma(current->mm, op.vaddr); 638 if (!vma || vma->vm_ops != &gntdev_vmops) 639 goto out_unlock; 640 641 map = vma->vm_private_data; 642 if (!map) 643 goto out_unlock; 644 645 op.offset = map->index << PAGE_SHIFT; 646 op.count = map->count; 647 rv = 0; 648 649 out_unlock: 650 mmap_read_unlock(current->mm); 651 652 if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0) 653 return -EFAULT; 654 return rv; 655 } 656 657 static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u) 658 { 659 struct ioctl_gntdev_unmap_notify op; 660 struct gntdev_grant_map *map; 661 int rc; 662 int out_flags; 663 evtchn_port_t out_event; 664 665 if (copy_from_user(&op, u, sizeof(op))) 666 return -EFAULT; 667 668 if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT)) 669 return -EINVAL; 670 671 /* We need to grab a reference to the event channel we are going to use 672 * to send the notify before releasing the reference we may already have 673 * (if someone has called this ioctl twice). This is required so that 674 * it is possible to change the clear_byte part of the notification 675 * without disturbing the event channel part, which may now be the last 676 * reference to that event channel. 677 */ 678 if (op.action & UNMAP_NOTIFY_SEND_EVENT) { 679 if (evtchn_get(op.event_channel_port)) 680 return -EINVAL; 681 } 682 683 out_flags = op.action; 684 out_event = op.event_channel_port; 685 686 mutex_lock(&priv->lock); 687 688 list_for_each_entry(map, &priv->maps, next) { 689 uint64_t begin = map->index << PAGE_SHIFT; 690 uint64_t end = (map->index + map->count) << PAGE_SHIFT; 691 if (op.index >= begin && op.index < end) 692 goto found; 693 } 694 rc = -ENOENT; 695 goto unlock_out; 696 697 found: 698 if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) && 699 (map->flags & GNTMAP_readonly)) { 700 rc = -EINVAL; 701 goto unlock_out; 702 } 703 704 out_flags = map->notify.flags; 705 out_event = map->notify.event; 706 707 map->notify.flags = op.action; 708 map->notify.addr = op.index - (map->index << PAGE_SHIFT); 709 map->notify.event = op.event_channel_port; 710 711 rc = 0; 712 713 unlock_out: 714 mutex_unlock(&priv->lock); 715 716 /* Drop the reference to the event channel we did not save in the map */ 717 if (out_flags & UNMAP_NOTIFY_SEND_EVENT) 718 evtchn_put(out_event); 719 720 return rc; 721 } 722 723 #define GNTDEV_COPY_BATCH 16 724 725 struct gntdev_copy_batch { 726 struct gnttab_copy ops[GNTDEV_COPY_BATCH]; 727 struct page *pages[GNTDEV_COPY_BATCH]; 728 s16 __user *status[GNTDEV_COPY_BATCH]; 729 unsigned int nr_ops; 730 unsigned int nr_pages; 731 bool writeable; 732 }; 733 734 static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt, 735 unsigned long *gfn) 736 { 737 unsigned long addr = (unsigned long)virt; 738 struct page *page; 739 unsigned long xen_pfn; 740 int ret; 741 742 ret = pin_user_pages_fast(addr, 1, batch->writeable ? FOLL_WRITE : 0, &page); 743 if (ret < 0) 744 return ret; 745 746 batch->pages[batch->nr_pages++] = page; 747 748 xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(addr & ~PAGE_MASK); 749 *gfn = pfn_to_gfn(xen_pfn); 750 751 return 0; 752 } 753 754 static void gntdev_put_pages(struct gntdev_copy_batch *batch) 755 { 756 unpin_user_pages_dirty_lock(batch->pages, batch->nr_pages, batch->writeable); 757 batch->nr_pages = 0; 758 batch->writeable = false; 759 } 760 761 static int gntdev_copy(struct gntdev_copy_batch *batch) 762 { 763 unsigned int i; 764 765 gnttab_batch_copy(batch->ops, batch->nr_ops); 766 gntdev_put_pages(batch); 767 768 /* 769 * For each completed op, update the status if the op failed 770 * and all previous ops for the segment were successful. 771 */ 772 for (i = 0; i < batch->nr_ops; i++) { 773 s16 status = batch->ops[i].status; 774 s16 old_status; 775 776 if (status == GNTST_okay) 777 continue; 778 779 if (__get_user(old_status, batch->status[i])) 780 return -EFAULT; 781 782 if (old_status != GNTST_okay) 783 continue; 784 785 if (__put_user(status, batch->status[i])) 786 return -EFAULT; 787 } 788 789 batch->nr_ops = 0; 790 return 0; 791 } 792 793 static int gntdev_grant_copy_seg(struct gntdev_copy_batch *batch, 794 struct gntdev_grant_copy_segment *seg, 795 s16 __user *status) 796 { 797 uint16_t copied = 0; 798 799 /* 800 * Disallow local -> local copies since there is only space in 801 * batch->pages for one page per-op and this would be a very 802 * expensive memcpy(). 803 */ 804 if (!(seg->flags & (GNTCOPY_source_gref | GNTCOPY_dest_gref))) 805 return -EINVAL; 806 807 /* Can't cross page if source/dest is a grant ref. */ 808 if (seg->flags & GNTCOPY_source_gref) { 809 if (seg->source.foreign.offset + seg->len > XEN_PAGE_SIZE) 810 return -EINVAL; 811 } 812 if (seg->flags & GNTCOPY_dest_gref) { 813 if (seg->dest.foreign.offset + seg->len > XEN_PAGE_SIZE) 814 return -EINVAL; 815 } 816 817 if (put_user(GNTST_okay, status)) 818 return -EFAULT; 819 820 while (copied < seg->len) { 821 struct gnttab_copy *op; 822 void __user *virt; 823 size_t len, off; 824 unsigned long gfn; 825 int ret; 826 827 if (batch->nr_ops >= GNTDEV_COPY_BATCH) { 828 ret = gntdev_copy(batch); 829 if (ret < 0) 830 return ret; 831 } 832 833 len = seg->len - copied; 834 835 op = &batch->ops[batch->nr_ops]; 836 op->flags = 0; 837 838 if (seg->flags & GNTCOPY_source_gref) { 839 op->source.u.ref = seg->source.foreign.ref; 840 op->source.domid = seg->source.foreign.domid; 841 op->source.offset = seg->source.foreign.offset + copied; 842 op->flags |= GNTCOPY_source_gref; 843 } else { 844 virt = seg->source.virt + copied; 845 off = (unsigned long)virt & ~XEN_PAGE_MASK; 846 len = min(len, (size_t)XEN_PAGE_SIZE - off); 847 batch->writeable = false; 848 849 ret = gntdev_get_page(batch, virt, &gfn); 850 if (ret < 0) 851 return ret; 852 853 op->source.u.gmfn = gfn; 854 op->source.domid = DOMID_SELF; 855 op->source.offset = off; 856 } 857 858 if (seg->flags & GNTCOPY_dest_gref) { 859 op->dest.u.ref = seg->dest.foreign.ref; 860 op->dest.domid = seg->dest.foreign.domid; 861 op->dest.offset = seg->dest.foreign.offset + copied; 862 op->flags |= GNTCOPY_dest_gref; 863 } else { 864 virt = seg->dest.virt + copied; 865 off = (unsigned long)virt & ~XEN_PAGE_MASK; 866 len = min(len, (size_t)XEN_PAGE_SIZE - off); 867 batch->writeable = true; 868 869 ret = gntdev_get_page(batch, virt, &gfn); 870 if (ret < 0) 871 return ret; 872 873 op->dest.u.gmfn = gfn; 874 op->dest.domid = DOMID_SELF; 875 op->dest.offset = off; 876 } 877 878 op->len = len; 879 copied += len; 880 881 batch->status[batch->nr_ops] = status; 882 batch->nr_ops++; 883 } 884 885 return 0; 886 } 887 888 static long gntdev_ioctl_grant_copy(struct gntdev_priv *priv, void __user *u) 889 { 890 struct ioctl_gntdev_grant_copy copy; 891 struct gntdev_copy_batch batch; 892 unsigned int i; 893 int ret = 0; 894 895 if (copy_from_user(©, u, sizeof(copy))) 896 return -EFAULT; 897 898 batch.nr_ops = 0; 899 batch.nr_pages = 0; 900 901 for (i = 0; i < copy.count; i++) { 902 struct gntdev_grant_copy_segment seg; 903 904 if (copy_from_user(&seg, ©.segments[i], sizeof(seg))) { 905 ret = -EFAULT; 906 goto out; 907 } 908 909 ret = gntdev_grant_copy_seg(&batch, &seg, ©.segments[i].status); 910 if (ret < 0) 911 goto out; 912 913 cond_resched(); 914 } 915 if (batch.nr_ops) 916 ret = gntdev_copy(&batch); 917 return ret; 918 919 out: 920 gntdev_put_pages(&batch); 921 return ret; 922 } 923 924 static long gntdev_ioctl(struct file *flip, 925 unsigned int cmd, unsigned long arg) 926 { 927 struct gntdev_priv *priv = flip->private_data; 928 void __user *ptr = (void __user *)arg; 929 930 switch (cmd) { 931 case IOCTL_GNTDEV_MAP_GRANT_REF: 932 return gntdev_ioctl_map_grant_ref(priv, ptr); 933 934 case IOCTL_GNTDEV_UNMAP_GRANT_REF: 935 return gntdev_ioctl_unmap_grant_ref(priv, ptr); 936 937 case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR: 938 return gntdev_ioctl_get_offset_for_vaddr(priv, ptr); 939 940 case IOCTL_GNTDEV_SET_UNMAP_NOTIFY: 941 return gntdev_ioctl_notify(priv, ptr); 942 943 case IOCTL_GNTDEV_GRANT_COPY: 944 return gntdev_ioctl_grant_copy(priv, ptr); 945 946 #ifdef CONFIG_XEN_GNTDEV_DMABUF 947 case IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS: 948 return gntdev_ioctl_dmabuf_exp_from_refs(priv, use_ptemod, ptr); 949 950 case IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED: 951 return gntdev_ioctl_dmabuf_exp_wait_released(priv, ptr); 952 953 case IOCTL_GNTDEV_DMABUF_IMP_TO_REFS: 954 return gntdev_ioctl_dmabuf_imp_to_refs(priv, ptr); 955 956 case IOCTL_GNTDEV_DMABUF_IMP_RELEASE: 957 return gntdev_ioctl_dmabuf_imp_release(priv, ptr); 958 #endif 959 960 default: 961 pr_debug("priv %p, unknown cmd %x\n", priv, cmd); 962 return -ENOIOCTLCMD; 963 } 964 965 return 0; 966 } 967 968 static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) 969 { 970 struct gntdev_priv *priv = flip->private_data; 971 int index = vma->vm_pgoff; 972 int count = vma_pages(vma); 973 struct gntdev_grant_map *map; 974 int err = -EINVAL; 975 976 if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED)) 977 return -EINVAL; 978 979 pr_debug("map %d+%d at %lx (pgoff %lx)\n", 980 index, count, vma->vm_start, vma->vm_pgoff); 981 982 mutex_lock(&priv->lock); 983 map = gntdev_find_map_index(priv, index, count); 984 if (!map) 985 goto unlock_out; 986 if (use_ptemod && map->vma) 987 goto unlock_out; 988 refcount_inc(&map->users); 989 990 vma->vm_ops = &gntdev_vmops; 991 992 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP; 993 994 if (use_ptemod) 995 vma->vm_flags |= VM_DONTCOPY; 996 997 vma->vm_private_data = map; 998 if (map->flags) { 999 if ((vma->vm_flags & VM_WRITE) && 1000 (map->flags & GNTMAP_readonly)) 1001 goto out_unlock_put; 1002 } else { 1003 map->flags = GNTMAP_host_map; 1004 if (!(vma->vm_flags & VM_WRITE)) 1005 map->flags |= GNTMAP_readonly; 1006 } 1007 1008 if (use_ptemod) { 1009 map->vma = vma; 1010 err = mmu_interval_notifier_insert_locked( 1011 &map->notifier, vma->vm_mm, vma->vm_start, 1012 vma->vm_end - vma->vm_start, &gntdev_mmu_ops); 1013 if (err) { 1014 map->vma = NULL; 1015 goto out_unlock_put; 1016 } 1017 } 1018 mutex_unlock(&priv->lock); 1019 1020 if (use_ptemod) { 1021 /* 1022 * gntdev takes the address of the PTE in find_grant_ptes() and 1023 * passes it to the hypervisor in gntdev_map_grant_pages(). The 1024 * purpose of the notifier is to prevent the hypervisor pointer 1025 * to the PTE from going stale. 1026 * 1027 * Since this vma's mappings can't be touched without the 1028 * mmap_lock, and we are holding it now, there is no need for 1029 * the notifier_range locking pattern. 1030 */ 1031 mmu_interval_read_begin(&map->notifier); 1032 1033 map->pages_vm_start = vma->vm_start; 1034 err = apply_to_page_range(vma->vm_mm, vma->vm_start, 1035 vma->vm_end - vma->vm_start, 1036 find_grant_ptes, map); 1037 if (err) { 1038 pr_warn("find_grant_ptes() failure.\n"); 1039 goto out_put_map; 1040 } 1041 } 1042 1043 err = gntdev_map_grant_pages(map); 1044 if (err) 1045 goto out_put_map; 1046 1047 if (!use_ptemod) { 1048 err = vm_map_pages_zero(vma, map->pages, map->count); 1049 if (err) 1050 goto out_put_map; 1051 } 1052 1053 return 0; 1054 1055 unlock_out: 1056 mutex_unlock(&priv->lock); 1057 return err; 1058 1059 out_unlock_put: 1060 mutex_unlock(&priv->lock); 1061 out_put_map: 1062 if (use_ptemod) { 1063 unmap_grant_pages(map, 0, map->count); 1064 if (map->vma) { 1065 mmu_interval_notifier_remove(&map->notifier); 1066 map->vma = NULL; 1067 } 1068 } 1069 gntdev_put_map(priv, map); 1070 return err; 1071 } 1072 1073 static const struct file_operations gntdev_fops = { 1074 .owner = THIS_MODULE, 1075 .open = gntdev_open, 1076 .release = gntdev_release, 1077 .mmap = gntdev_mmap, 1078 .unlocked_ioctl = gntdev_ioctl 1079 }; 1080 1081 static struct miscdevice gntdev_miscdev = { 1082 .minor = MISC_DYNAMIC_MINOR, 1083 .name = "xen/gntdev", 1084 .fops = &gntdev_fops, 1085 }; 1086 1087 /* ------------------------------------------------------------------ */ 1088 1089 static int __init gntdev_init(void) 1090 { 1091 int err; 1092 1093 if (!xen_domain()) 1094 return -ENODEV; 1095 1096 use_ptemod = !xen_feature(XENFEAT_auto_translated_physmap); 1097 1098 err = misc_register(&gntdev_miscdev); 1099 if (err != 0) { 1100 pr_err("Could not register gntdev device\n"); 1101 return err; 1102 } 1103 return 0; 1104 } 1105 1106 static void __exit gntdev_exit(void) 1107 { 1108 misc_deregister(&gntdev_miscdev); 1109 } 1110 1111 module_init(gntdev_init); 1112 module_exit(gntdev_exit); 1113 1114 /* ------------------------------------------------------------------ */ 1115