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 u64 pte_maddr; 271 272 BUG_ON(pgnr >= map->count); 273 pte_maddr = arbitrary_virt_to_machine(pte).maddr; 274 275 /* 276 * Set the PTE as special to force get_user_pages_fast() fall 277 * back to the slow path. If this is not supported as part of 278 * the grant map, it will be done afterwards. 279 */ 280 if (xen_feature(XENFEAT_gnttab_map_avail_bits)) 281 flags |= (1 << _GNTMAP_guest_avail0); 282 283 gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags, 284 map->grants[pgnr].ref, 285 map->grants[pgnr].domid); 286 gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags, 287 INVALID_GRANT_HANDLE); 288 return 0; 289 } 290 291 #ifdef CONFIG_X86 292 static int set_grant_ptes_as_special(pte_t *pte, unsigned long addr, void *data) 293 { 294 set_pte_at(current->mm, addr, pte, pte_mkspecial(*pte)); 295 return 0; 296 } 297 #endif 298 299 int gntdev_map_grant_pages(struct gntdev_grant_map *map) 300 { 301 int i, err = 0; 302 303 if (!use_ptemod) { 304 /* Note: it could already be mapped */ 305 if (map->map_ops[0].handle != INVALID_GRANT_HANDLE) 306 return 0; 307 for (i = 0; i < map->count; i++) { 308 unsigned long addr = (unsigned long) 309 pfn_to_kaddr(page_to_pfn(map->pages[i])); 310 gnttab_set_map_op(&map->map_ops[i], addr, map->flags, 311 map->grants[i].ref, 312 map->grants[i].domid); 313 gnttab_set_unmap_op(&map->unmap_ops[i], addr, 314 map->flags, INVALID_GRANT_HANDLE); 315 } 316 } else { 317 /* 318 * Setup the map_ops corresponding to the pte entries pointing 319 * to the kernel linear addresses of the struct pages. 320 * These ptes are completely different from the user ptes dealt 321 * with find_grant_ptes. 322 * Note that GNTMAP_device_map isn't needed here: The 323 * dev_bus_addr output field gets consumed only from ->map_ops, 324 * and by not requesting it when mapping we also avoid needing 325 * to mirror dev_bus_addr into ->unmap_ops (and holding an extra 326 * reference to the page in the hypervisor). 327 */ 328 unsigned int flags = (map->flags & ~GNTMAP_device_map) | 329 GNTMAP_host_map; 330 331 for (i = 0; i < map->count; i++) { 332 unsigned long address = (unsigned long) 333 pfn_to_kaddr(page_to_pfn(map->pages[i])); 334 BUG_ON(PageHighMem(map->pages[i])); 335 336 gnttab_set_map_op(&map->kmap_ops[i], address, flags, 337 map->grants[i].ref, 338 map->grants[i].domid); 339 gnttab_set_unmap_op(&map->kunmap_ops[i], address, 340 flags, INVALID_GRANT_HANDLE); 341 } 342 } 343 344 pr_debug("map %d+%d\n", map->index, map->count); 345 err = gnttab_map_refs(map->map_ops, map->kmap_ops, map->pages, 346 map->count); 347 348 for (i = 0; i < map->count; i++) { 349 if (map->map_ops[i].status == GNTST_okay) 350 map->unmap_ops[i].handle = map->map_ops[i].handle; 351 else if (!err) 352 err = -EINVAL; 353 354 if (map->flags & GNTMAP_device_map) 355 map->unmap_ops[i].dev_bus_addr = map->map_ops[i].dev_bus_addr; 356 357 if (use_ptemod) { 358 if (map->kmap_ops[i].status == GNTST_okay) 359 map->kunmap_ops[i].handle = map->kmap_ops[i].handle; 360 else if (!err) 361 err = -EINVAL; 362 } 363 } 364 return err; 365 } 366 367 static int __unmap_grant_pages(struct gntdev_grant_map *map, int offset, 368 int pages) 369 { 370 int i, err = 0; 371 struct gntab_unmap_queue_data unmap_data; 372 373 if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) { 374 int pgno = (map->notify.addr >> PAGE_SHIFT); 375 if (pgno >= offset && pgno < offset + pages) { 376 /* No need for kmap, pages are in lowmem */ 377 uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno])); 378 tmp[map->notify.addr & (PAGE_SIZE-1)] = 0; 379 map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE; 380 } 381 } 382 383 unmap_data.unmap_ops = map->unmap_ops + offset; 384 unmap_data.kunmap_ops = use_ptemod ? map->kunmap_ops + offset : NULL; 385 unmap_data.pages = map->pages + offset; 386 unmap_data.count = pages; 387 388 err = gnttab_unmap_refs_sync(&unmap_data); 389 if (err) 390 return err; 391 392 for (i = 0; i < pages; i++) { 393 if (map->unmap_ops[offset+i].status) 394 err = -EINVAL; 395 pr_debug("unmap handle=%d st=%d\n", 396 map->unmap_ops[offset+i].handle, 397 map->unmap_ops[offset+i].status); 398 map->unmap_ops[offset+i].handle = INVALID_GRANT_HANDLE; 399 } 400 return err; 401 } 402 403 static int unmap_grant_pages(struct gntdev_grant_map *map, int offset, 404 int pages) 405 { 406 int range, err = 0; 407 408 pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages); 409 410 /* It is possible the requested range will have a "hole" where we 411 * already unmapped some of the grants. Only unmap valid ranges. 412 */ 413 while (pages && !err) { 414 while (pages && 415 map->unmap_ops[offset].handle == INVALID_GRANT_HANDLE) { 416 offset++; 417 pages--; 418 } 419 range = 0; 420 while (range < pages) { 421 if (map->unmap_ops[offset + range].handle == 422 INVALID_GRANT_HANDLE) 423 break; 424 range++; 425 } 426 err = __unmap_grant_pages(map, offset, range); 427 offset += range; 428 pages -= range; 429 } 430 431 return err; 432 } 433 434 /* ------------------------------------------------------------------ */ 435 436 static void gntdev_vma_open(struct vm_area_struct *vma) 437 { 438 struct gntdev_grant_map *map = vma->vm_private_data; 439 440 pr_debug("gntdev_vma_open %p\n", vma); 441 refcount_inc(&map->users); 442 } 443 444 static void gntdev_vma_close(struct vm_area_struct *vma) 445 { 446 struct gntdev_grant_map *map = vma->vm_private_data; 447 struct file *file = vma->vm_file; 448 struct gntdev_priv *priv = file->private_data; 449 450 pr_debug("gntdev_vma_close %p\n", vma); 451 if (use_ptemod) { 452 WARN_ON(map->vma != vma); 453 mmu_interval_notifier_remove(&map->notifier); 454 map->vma = NULL; 455 } 456 vma->vm_private_data = NULL; 457 gntdev_put_map(priv, map); 458 } 459 460 static struct page *gntdev_vma_find_special_page(struct vm_area_struct *vma, 461 unsigned long addr) 462 { 463 struct gntdev_grant_map *map = vma->vm_private_data; 464 465 return map->pages[(addr - map->pages_vm_start) >> PAGE_SHIFT]; 466 } 467 468 static const struct vm_operations_struct gntdev_vmops = { 469 .open = gntdev_vma_open, 470 .close = gntdev_vma_close, 471 .find_special_page = gntdev_vma_find_special_page, 472 }; 473 474 /* ------------------------------------------------------------------ */ 475 476 static bool gntdev_invalidate(struct mmu_interval_notifier *mn, 477 const struct mmu_notifier_range *range, 478 unsigned long cur_seq) 479 { 480 struct gntdev_grant_map *map = 481 container_of(mn, struct gntdev_grant_map, notifier); 482 unsigned long mstart, mend; 483 int err; 484 485 if (!mmu_notifier_range_blockable(range)) 486 return false; 487 488 /* 489 * If the VMA is split or otherwise changed the notifier is not 490 * updated, but we don't want to process VA's outside the modified 491 * VMA. FIXME: It would be much more understandable to just prevent 492 * modifying the VMA in the first place. 493 */ 494 if (map->vma->vm_start >= range->end || 495 map->vma->vm_end <= range->start) 496 return true; 497 498 mstart = max(range->start, map->vma->vm_start); 499 mend = min(range->end, map->vma->vm_end); 500 pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n", 501 map->index, map->count, 502 map->vma->vm_start, map->vma->vm_end, 503 range->start, range->end, mstart, mend); 504 err = unmap_grant_pages(map, 505 (mstart - map->vma->vm_start) >> PAGE_SHIFT, 506 (mend - mstart) >> PAGE_SHIFT); 507 WARN_ON(err); 508 509 return true; 510 } 511 512 static const struct mmu_interval_notifier_ops gntdev_mmu_ops = { 513 .invalidate = gntdev_invalidate, 514 }; 515 516 /* ------------------------------------------------------------------ */ 517 518 static int gntdev_open(struct inode *inode, struct file *flip) 519 { 520 struct gntdev_priv *priv; 521 522 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 523 if (!priv) 524 return -ENOMEM; 525 526 INIT_LIST_HEAD(&priv->maps); 527 mutex_init(&priv->lock); 528 529 #ifdef CONFIG_XEN_GNTDEV_DMABUF 530 priv->dmabuf_priv = gntdev_dmabuf_init(flip); 531 if (IS_ERR(priv->dmabuf_priv)) { 532 int ret = PTR_ERR(priv->dmabuf_priv); 533 534 kfree(priv); 535 return ret; 536 } 537 #endif 538 539 flip->private_data = priv; 540 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC 541 priv->dma_dev = gntdev_miscdev.this_device; 542 dma_coerce_mask_and_coherent(priv->dma_dev, DMA_BIT_MASK(64)); 543 #endif 544 pr_debug("priv %p\n", priv); 545 546 return 0; 547 } 548 549 static int gntdev_release(struct inode *inode, struct file *flip) 550 { 551 struct gntdev_priv *priv = flip->private_data; 552 struct gntdev_grant_map *map; 553 554 pr_debug("priv %p\n", priv); 555 556 mutex_lock(&priv->lock); 557 while (!list_empty(&priv->maps)) { 558 map = list_entry(priv->maps.next, 559 struct gntdev_grant_map, next); 560 list_del(&map->next); 561 gntdev_put_map(NULL /* already removed */, map); 562 } 563 mutex_unlock(&priv->lock); 564 565 #ifdef CONFIG_XEN_GNTDEV_DMABUF 566 gntdev_dmabuf_fini(priv->dmabuf_priv); 567 #endif 568 569 kfree(priv); 570 return 0; 571 } 572 573 static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv, 574 struct ioctl_gntdev_map_grant_ref __user *u) 575 { 576 struct ioctl_gntdev_map_grant_ref op; 577 struct gntdev_grant_map *map; 578 int err; 579 580 if (copy_from_user(&op, u, sizeof(op)) != 0) 581 return -EFAULT; 582 pr_debug("priv %p, add %d\n", priv, op.count); 583 if (unlikely(gntdev_test_page_count(op.count))) 584 return -EINVAL; 585 586 err = -ENOMEM; 587 map = gntdev_alloc_map(priv, op.count, 0 /* This is not a dma-buf. */); 588 if (!map) 589 return err; 590 591 if (copy_from_user(map->grants, &u->refs, 592 sizeof(map->grants[0]) * op.count) != 0) { 593 gntdev_put_map(NULL, map); 594 return -EFAULT; 595 } 596 597 mutex_lock(&priv->lock); 598 gntdev_add_map(priv, map); 599 op.index = map->index << PAGE_SHIFT; 600 mutex_unlock(&priv->lock); 601 602 if (copy_to_user(u, &op, sizeof(op)) != 0) 603 return -EFAULT; 604 605 return 0; 606 } 607 608 static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv, 609 struct ioctl_gntdev_unmap_grant_ref __user *u) 610 { 611 struct ioctl_gntdev_unmap_grant_ref op; 612 struct gntdev_grant_map *map; 613 int err = -ENOENT; 614 615 if (copy_from_user(&op, u, sizeof(op)) != 0) 616 return -EFAULT; 617 pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count); 618 619 mutex_lock(&priv->lock); 620 map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count); 621 if (map) { 622 list_del(&map->next); 623 err = 0; 624 } 625 mutex_unlock(&priv->lock); 626 if (map) 627 gntdev_put_map(priv, map); 628 return err; 629 } 630 631 static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv, 632 struct ioctl_gntdev_get_offset_for_vaddr __user *u) 633 { 634 struct ioctl_gntdev_get_offset_for_vaddr op; 635 struct vm_area_struct *vma; 636 struct gntdev_grant_map *map; 637 int rv = -EINVAL; 638 639 if (copy_from_user(&op, u, sizeof(op)) != 0) 640 return -EFAULT; 641 pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr); 642 643 mmap_read_lock(current->mm); 644 vma = find_vma(current->mm, op.vaddr); 645 if (!vma || vma->vm_ops != &gntdev_vmops) 646 goto out_unlock; 647 648 map = vma->vm_private_data; 649 if (!map) 650 goto out_unlock; 651 652 op.offset = map->index << PAGE_SHIFT; 653 op.count = map->count; 654 rv = 0; 655 656 out_unlock: 657 mmap_read_unlock(current->mm); 658 659 if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0) 660 return -EFAULT; 661 return rv; 662 } 663 664 static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u) 665 { 666 struct ioctl_gntdev_unmap_notify op; 667 struct gntdev_grant_map *map; 668 int rc; 669 int out_flags; 670 evtchn_port_t out_event; 671 672 if (copy_from_user(&op, u, sizeof(op))) 673 return -EFAULT; 674 675 if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT)) 676 return -EINVAL; 677 678 /* We need to grab a reference to the event channel we are going to use 679 * to send the notify before releasing the reference we may already have 680 * (if someone has called this ioctl twice). This is required so that 681 * it is possible to change the clear_byte part of the notification 682 * without disturbing the event channel part, which may now be the last 683 * reference to that event channel. 684 */ 685 if (op.action & UNMAP_NOTIFY_SEND_EVENT) { 686 if (evtchn_get(op.event_channel_port)) 687 return -EINVAL; 688 } 689 690 out_flags = op.action; 691 out_event = op.event_channel_port; 692 693 mutex_lock(&priv->lock); 694 695 list_for_each_entry(map, &priv->maps, next) { 696 uint64_t begin = map->index << PAGE_SHIFT; 697 uint64_t end = (map->index + map->count) << PAGE_SHIFT; 698 if (op.index >= begin && op.index < end) 699 goto found; 700 } 701 rc = -ENOENT; 702 goto unlock_out; 703 704 found: 705 if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) && 706 (map->flags & GNTMAP_readonly)) { 707 rc = -EINVAL; 708 goto unlock_out; 709 } 710 711 out_flags = map->notify.flags; 712 out_event = map->notify.event; 713 714 map->notify.flags = op.action; 715 map->notify.addr = op.index - (map->index << PAGE_SHIFT); 716 map->notify.event = op.event_channel_port; 717 718 rc = 0; 719 720 unlock_out: 721 mutex_unlock(&priv->lock); 722 723 /* Drop the reference to the event channel we did not save in the map */ 724 if (out_flags & UNMAP_NOTIFY_SEND_EVENT) 725 evtchn_put(out_event); 726 727 return rc; 728 } 729 730 #define GNTDEV_COPY_BATCH 16 731 732 struct gntdev_copy_batch { 733 struct gnttab_copy ops[GNTDEV_COPY_BATCH]; 734 struct page *pages[GNTDEV_COPY_BATCH]; 735 s16 __user *status[GNTDEV_COPY_BATCH]; 736 unsigned int nr_ops; 737 unsigned int nr_pages; 738 bool writeable; 739 }; 740 741 static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt, 742 unsigned long *gfn) 743 { 744 unsigned long addr = (unsigned long)virt; 745 struct page *page; 746 unsigned long xen_pfn; 747 int ret; 748 749 ret = pin_user_pages_fast(addr, 1, batch->writeable ? FOLL_WRITE : 0, &page); 750 if (ret < 0) 751 return ret; 752 753 batch->pages[batch->nr_pages++] = page; 754 755 xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(addr & ~PAGE_MASK); 756 *gfn = pfn_to_gfn(xen_pfn); 757 758 return 0; 759 } 760 761 static void gntdev_put_pages(struct gntdev_copy_batch *batch) 762 { 763 unpin_user_pages_dirty_lock(batch->pages, batch->nr_pages, batch->writeable); 764 batch->nr_pages = 0; 765 batch->writeable = false; 766 } 767 768 static int gntdev_copy(struct gntdev_copy_batch *batch) 769 { 770 unsigned int i; 771 772 gnttab_batch_copy(batch->ops, batch->nr_ops); 773 gntdev_put_pages(batch); 774 775 /* 776 * For each completed op, update the status if the op failed 777 * and all previous ops for the segment were successful. 778 */ 779 for (i = 0; i < batch->nr_ops; i++) { 780 s16 status = batch->ops[i].status; 781 s16 old_status; 782 783 if (status == GNTST_okay) 784 continue; 785 786 if (__get_user(old_status, batch->status[i])) 787 return -EFAULT; 788 789 if (old_status != GNTST_okay) 790 continue; 791 792 if (__put_user(status, batch->status[i])) 793 return -EFAULT; 794 } 795 796 batch->nr_ops = 0; 797 return 0; 798 } 799 800 static int gntdev_grant_copy_seg(struct gntdev_copy_batch *batch, 801 struct gntdev_grant_copy_segment *seg, 802 s16 __user *status) 803 { 804 uint16_t copied = 0; 805 806 /* 807 * Disallow local -> local copies since there is only space in 808 * batch->pages for one page per-op and this would be a very 809 * expensive memcpy(). 810 */ 811 if (!(seg->flags & (GNTCOPY_source_gref | GNTCOPY_dest_gref))) 812 return -EINVAL; 813 814 /* Can't cross page if source/dest is a grant ref. */ 815 if (seg->flags & GNTCOPY_source_gref) { 816 if (seg->source.foreign.offset + seg->len > XEN_PAGE_SIZE) 817 return -EINVAL; 818 } 819 if (seg->flags & GNTCOPY_dest_gref) { 820 if (seg->dest.foreign.offset + seg->len > XEN_PAGE_SIZE) 821 return -EINVAL; 822 } 823 824 if (put_user(GNTST_okay, status)) 825 return -EFAULT; 826 827 while (copied < seg->len) { 828 struct gnttab_copy *op; 829 void __user *virt; 830 size_t len, off; 831 unsigned long gfn; 832 int ret; 833 834 if (batch->nr_ops >= GNTDEV_COPY_BATCH) { 835 ret = gntdev_copy(batch); 836 if (ret < 0) 837 return ret; 838 } 839 840 len = seg->len - copied; 841 842 op = &batch->ops[batch->nr_ops]; 843 op->flags = 0; 844 845 if (seg->flags & GNTCOPY_source_gref) { 846 op->source.u.ref = seg->source.foreign.ref; 847 op->source.domid = seg->source.foreign.domid; 848 op->source.offset = seg->source.foreign.offset + copied; 849 op->flags |= GNTCOPY_source_gref; 850 } else { 851 virt = seg->source.virt + copied; 852 off = (unsigned long)virt & ~XEN_PAGE_MASK; 853 len = min(len, (size_t)XEN_PAGE_SIZE - off); 854 batch->writeable = false; 855 856 ret = gntdev_get_page(batch, virt, &gfn); 857 if (ret < 0) 858 return ret; 859 860 op->source.u.gmfn = gfn; 861 op->source.domid = DOMID_SELF; 862 op->source.offset = off; 863 } 864 865 if (seg->flags & GNTCOPY_dest_gref) { 866 op->dest.u.ref = seg->dest.foreign.ref; 867 op->dest.domid = seg->dest.foreign.domid; 868 op->dest.offset = seg->dest.foreign.offset + copied; 869 op->flags |= GNTCOPY_dest_gref; 870 } else { 871 virt = seg->dest.virt + copied; 872 off = (unsigned long)virt & ~XEN_PAGE_MASK; 873 len = min(len, (size_t)XEN_PAGE_SIZE - off); 874 batch->writeable = true; 875 876 ret = gntdev_get_page(batch, virt, &gfn); 877 if (ret < 0) 878 return ret; 879 880 op->dest.u.gmfn = gfn; 881 op->dest.domid = DOMID_SELF; 882 op->dest.offset = off; 883 } 884 885 op->len = len; 886 copied += len; 887 888 batch->status[batch->nr_ops] = status; 889 batch->nr_ops++; 890 } 891 892 return 0; 893 } 894 895 static long gntdev_ioctl_grant_copy(struct gntdev_priv *priv, void __user *u) 896 { 897 struct ioctl_gntdev_grant_copy copy; 898 struct gntdev_copy_batch batch; 899 unsigned int i; 900 int ret = 0; 901 902 if (copy_from_user(©, u, sizeof(copy))) 903 return -EFAULT; 904 905 batch.nr_ops = 0; 906 batch.nr_pages = 0; 907 908 for (i = 0; i < copy.count; i++) { 909 struct gntdev_grant_copy_segment seg; 910 911 if (copy_from_user(&seg, ©.segments[i], sizeof(seg))) { 912 ret = -EFAULT; 913 goto out; 914 } 915 916 ret = gntdev_grant_copy_seg(&batch, &seg, ©.segments[i].status); 917 if (ret < 0) 918 goto out; 919 920 cond_resched(); 921 } 922 if (batch.nr_ops) 923 ret = gntdev_copy(&batch); 924 return ret; 925 926 out: 927 gntdev_put_pages(&batch); 928 return ret; 929 } 930 931 static long gntdev_ioctl(struct file *flip, 932 unsigned int cmd, unsigned long arg) 933 { 934 struct gntdev_priv *priv = flip->private_data; 935 void __user *ptr = (void __user *)arg; 936 937 switch (cmd) { 938 case IOCTL_GNTDEV_MAP_GRANT_REF: 939 return gntdev_ioctl_map_grant_ref(priv, ptr); 940 941 case IOCTL_GNTDEV_UNMAP_GRANT_REF: 942 return gntdev_ioctl_unmap_grant_ref(priv, ptr); 943 944 case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR: 945 return gntdev_ioctl_get_offset_for_vaddr(priv, ptr); 946 947 case IOCTL_GNTDEV_SET_UNMAP_NOTIFY: 948 return gntdev_ioctl_notify(priv, ptr); 949 950 case IOCTL_GNTDEV_GRANT_COPY: 951 return gntdev_ioctl_grant_copy(priv, ptr); 952 953 #ifdef CONFIG_XEN_GNTDEV_DMABUF 954 case IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS: 955 return gntdev_ioctl_dmabuf_exp_from_refs(priv, use_ptemod, ptr); 956 957 case IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED: 958 return gntdev_ioctl_dmabuf_exp_wait_released(priv, ptr); 959 960 case IOCTL_GNTDEV_DMABUF_IMP_TO_REFS: 961 return gntdev_ioctl_dmabuf_imp_to_refs(priv, ptr); 962 963 case IOCTL_GNTDEV_DMABUF_IMP_RELEASE: 964 return gntdev_ioctl_dmabuf_imp_release(priv, ptr); 965 #endif 966 967 default: 968 pr_debug("priv %p, unknown cmd %x\n", priv, cmd); 969 return -ENOIOCTLCMD; 970 } 971 972 return 0; 973 } 974 975 static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) 976 { 977 struct gntdev_priv *priv = flip->private_data; 978 int index = vma->vm_pgoff; 979 int count = vma_pages(vma); 980 struct gntdev_grant_map *map; 981 int err = -EINVAL; 982 983 if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED)) 984 return -EINVAL; 985 986 pr_debug("map %d+%d at %lx (pgoff %lx)\n", 987 index, count, vma->vm_start, vma->vm_pgoff); 988 989 mutex_lock(&priv->lock); 990 map = gntdev_find_map_index(priv, index, count); 991 if (!map) 992 goto unlock_out; 993 if (use_ptemod && map->vma) 994 goto unlock_out; 995 refcount_inc(&map->users); 996 997 vma->vm_ops = &gntdev_vmops; 998 999 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP; 1000 1001 if (use_ptemod) 1002 vma->vm_flags |= VM_DONTCOPY; 1003 1004 vma->vm_private_data = map; 1005 if (map->flags) { 1006 if ((vma->vm_flags & VM_WRITE) && 1007 (map->flags & GNTMAP_readonly)) 1008 goto out_unlock_put; 1009 } else { 1010 map->flags = GNTMAP_host_map; 1011 if (!(vma->vm_flags & VM_WRITE)) 1012 map->flags |= GNTMAP_readonly; 1013 } 1014 1015 if (use_ptemod) { 1016 map->vma = vma; 1017 err = mmu_interval_notifier_insert_locked( 1018 &map->notifier, vma->vm_mm, vma->vm_start, 1019 vma->vm_end - vma->vm_start, &gntdev_mmu_ops); 1020 if (err) 1021 goto out_unlock_put; 1022 } 1023 mutex_unlock(&priv->lock); 1024 1025 if (use_ptemod) { 1026 /* 1027 * gntdev takes the address of the PTE in find_grant_ptes() and 1028 * passes it to the hypervisor in gntdev_map_grant_pages(). The 1029 * purpose of the notifier is to prevent the hypervisor pointer 1030 * to the PTE from going stale. 1031 * 1032 * Since this vma's mappings can't be touched without the 1033 * mmap_lock, and we are holding it now, there is no need for 1034 * the notifier_range locking pattern. 1035 */ 1036 mmu_interval_read_begin(&map->notifier); 1037 1038 map->pages_vm_start = vma->vm_start; 1039 err = apply_to_page_range(vma->vm_mm, vma->vm_start, 1040 vma->vm_end - vma->vm_start, 1041 find_grant_ptes, map); 1042 if (err) { 1043 pr_warn("find_grant_ptes() failure.\n"); 1044 goto out_put_map; 1045 } 1046 } 1047 1048 err = gntdev_map_grant_pages(map); 1049 if (err) 1050 goto out_put_map; 1051 1052 if (!use_ptemod) { 1053 err = vm_map_pages_zero(vma, map->pages, map->count); 1054 if (err) 1055 goto out_put_map; 1056 } else { 1057 #ifdef CONFIG_X86 1058 /* 1059 * If the PTEs were not made special by the grant map 1060 * hypercall, do so here. 1061 * 1062 * This is racy since the mapping is already visible 1063 * to userspace but userspace should be well-behaved 1064 * enough to not touch it until the mmap() call 1065 * returns. 1066 */ 1067 if (!xen_feature(XENFEAT_gnttab_map_avail_bits)) { 1068 apply_to_page_range(vma->vm_mm, vma->vm_start, 1069 vma->vm_end - vma->vm_start, 1070 set_grant_ptes_as_special, NULL); 1071 } 1072 #endif 1073 } 1074 1075 return 0; 1076 1077 unlock_out: 1078 mutex_unlock(&priv->lock); 1079 return err; 1080 1081 out_unlock_put: 1082 mutex_unlock(&priv->lock); 1083 out_put_map: 1084 if (use_ptemod) { 1085 unmap_grant_pages(map, 0, map->count); 1086 if (map->vma) { 1087 mmu_interval_notifier_remove(&map->notifier); 1088 map->vma = NULL; 1089 } 1090 } 1091 gntdev_put_map(priv, map); 1092 return err; 1093 } 1094 1095 static const struct file_operations gntdev_fops = { 1096 .owner = THIS_MODULE, 1097 .open = gntdev_open, 1098 .release = gntdev_release, 1099 .mmap = gntdev_mmap, 1100 .unlocked_ioctl = gntdev_ioctl 1101 }; 1102 1103 static struct miscdevice gntdev_miscdev = { 1104 .minor = MISC_DYNAMIC_MINOR, 1105 .name = "xen/gntdev", 1106 .fops = &gntdev_fops, 1107 }; 1108 1109 /* ------------------------------------------------------------------ */ 1110 1111 static int __init gntdev_init(void) 1112 { 1113 int err; 1114 1115 if (!xen_domain()) 1116 return -ENODEV; 1117 1118 use_ptemod = !xen_feature(XENFEAT_auto_translated_physmap); 1119 1120 err = misc_register(&gntdev_miscdev); 1121 if (err != 0) { 1122 pr_err("Could not register gntdev device\n"); 1123 return err; 1124 } 1125 return 0; 1126 } 1127 1128 static void __exit gntdev_exit(void) 1129 { 1130 misc_deregister(&gntdev_miscdev); 1131 } 1132 1133 module_init(gntdev_init); 1134 module_exit(gntdev_exit); 1135 1136 /* ------------------------------------------------------------------ */ 1137