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 #include <linux/workqueue.h> 39 40 #include <xen/xen.h> 41 #include <xen/grant_table.h> 42 #include <xen/balloon.h> 43 #include <xen/gntdev.h> 44 #include <xen/events.h> 45 #include <xen/page.h> 46 #include <asm/xen/hypervisor.h> 47 #include <asm/xen/hypercall.h> 48 49 #include "gntdev-common.h" 50 #ifdef CONFIG_XEN_GNTDEV_DMABUF 51 #include "gntdev-dmabuf.h" 52 #endif 53 54 MODULE_LICENSE("GPL"); 55 MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, " 56 "Gerd Hoffmann <kraxel@redhat.com>"); 57 MODULE_DESCRIPTION("User-space granted page access driver"); 58 59 #define GNTDEV_COPY_BATCH 16 60 61 struct gntdev_copy_batch { 62 struct gnttab_copy ops[GNTDEV_COPY_BATCH]; 63 struct page *pages[GNTDEV_COPY_BATCH]; 64 s16 __user *status[GNTDEV_COPY_BATCH]; 65 unsigned int nr_ops; 66 unsigned int nr_pages; 67 bool writeable; 68 struct gntdev_copy_batch *next; 69 }; 70 71 static unsigned int limit = 64*1024; 72 module_param(limit, uint, 0644); 73 MODULE_PARM_DESC(limit, 74 "Maximum number of grants that may be mapped by one mapping request"); 75 76 static void unmap_grant_pages(struct gntdev_grant_map *map, 77 int offset, int pages); 78 79 static struct miscdevice gntdev_miscdev; 80 81 /* ------------------------------------------------------------------ */ 82 83 bool gntdev_test_page_count(unsigned int count) 84 { 85 return !count || count > limit; 86 } 87 88 static void gntdev_print_maps(struct gntdev_priv *priv, 89 char *text, int text_index) 90 { 91 #ifdef DEBUG 92 struct gntdev_grant_map *map; 93 94 pr_debug("%s: maps list (priv %p)\n", __func__, priv); 95 list_for_each_entry(map, &priv->maps, next) 96 pr_debug(" index %2d, count %2d %s\n", 97 map->index, map->count, 98 map->index == text_index && text ? text : ""); 99 #endif 100 } 101 102 static void gntdev_free_map(struct gntdev_grant_map *map) 103 { 104 if (map == NULL) 105 return; 106 107 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC 108 if (map->dma_vaddr) { 109 struct gnttab_dma_alloc_args args; 110 111 args.dev = map->dma_dev; 112 args.coherent = !!(map->dma_flags & GNTDEV_DMA_FLAG_COHERENT); 113 args.nr_pages = map->count; 114 args.pages = map->pages; 115 args.frames = map->frames; 116 args.vaddr = map->dma_vaddr; 117 args.dev_bus_addr = map->dma_bus_addr; 118 119 gnttab_dma_free_pages(&args); 120 } else 121 #endif 122 if (map->pages) 123 gnttab_free_pages(map->count, map->pages); 124 125 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC 126 kvfree(map->frames); 127 #endif 128 kvfree(map->pages); 129 kvfree(map->grants); 130 kvfree(map->map_ops); 131 kvfree(map->unmap_ops); 132 kvfree(map->kmap_ops); 133 kvfree(map->kunmap_ops); 134 kvfree(map->being_removed); 135 kfree(map); 136 } 137 138 struct gntdev_grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count, 139 int dma_flags) 140 { 141 struct gntdev_grant_map *add; 142 int i; 143 144 add = kzalloc(sizeof(*add), GFP_KERNEL); 145 if (NULL == add) 146 return NULL; 147 148 add->grants = kvmalloc_array(count, sizeof(add->grants[0]), 149 GFP_KERNEL); 150 add->map_ops = kvmalloc_array(count, sizeof(add->map_ops[0]), 151 GFP_KERNEL); 152 add->unmap_ops = kvmalloc_array(count, sizeof(add->unmap_ops[0]), 153 GFP_KERNEL); 154 add->pages = kvcalloc(count, sizeof(add->pages[0]), GFP_KERNEL); 155 add->being_removed = 156 kvcalloc(count, sizeof(add->being_removed[0]), GFP_KERNEL); 157 if (NULL == add->grants || 158 NULL == add->map_ops || 159 NULL == add->unmap_ops || 160 NULL == add->pages || 161 NULL == add->being_removed) 162 goto err; 163 if (xen_pv_domain()) { 164 add->kmap_ops = kvmalloc_array(count, sizeof(add->kmap_ops[0]), 165 GFP_KERNEL); 166 add->kunmap_ops = kvmalloc_array(count, sizeof(add->kunmap_ops[0]), 167 GFP_KERNEL); 168 if (NULL == add->kmap_ops || NULL == add->kunmap_ops) 169 goto err; 170 } 171 172 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC 173 add->dma_flags = dma_flags; 174 175 /* 176 * Check if this mapping is requested to be backed 177 * by a DMA buffer. 178 */ 179 if (dma_flags & (GNTDEV_DMA_FLAG_WC | GNTDEV_DMA_FLAG_COHERENT)) { 180 struct gnttab_dma_alloc_args args; 181 182 add->frames = kvcalloc(count, sizeof(add->frames[0]), 183 GFP_KERNEL); 184 if (!add->frames) 185 goto err; 186 187 /* Remember the device, so we can free DMA memory. */ 188 add->dma_dev = priv->dma_dev; 189 190 args.dev = priv->dma_dev; 191 args.coherent = !!(dma_flags & GNTDEV_DMA_FLAG_COHERENT); 192 args.nr_pages = count; 193 args.pages = add->pages; 194 args.frames = add->frames; 195 196 if (gnttab_dma_alloc_pages(&args)) 197 goto err; 198 199 add->dma_vaddr = args.vaddr; 200 add->dma_bus_addr = args.dev_bus_addr; 201 } else 202 #endif 203 if (gnttab_alloc_pages(count, add->pages)) 204 goto err; 205 206 for (i = 0; i < count; i++) { 207 add->grants[i].domid = DOMID_INVALID; 208 add->grants[i].ref = INVALID_GRANT_REF; 209 add->map_ops[i].handle = INVALID_GRANT_HANDLE; 210 add->unmap_ops[i].handle = INVALID_GRANT_HANDLE; 211 if (xen_pv_domain()) { 212 add->kmap_ops[i].handle = INVALID_GRANT_HANDLE; 213 add->kunmap_ops[i].handle = INVALID_GRANT_HANDLE; 214 } 215 } 216 217 add->index = 0; 218 add->count = count; 219 refcount_set(&add->users, 1); 220 221 return add; 222 223 err: 224 gntdev_free_map(add); 225 return NULL; 226 } 227 228 void gntdev_add_map(struct gntdev_priv *priv, struct gntdev_grant_map *add) 229 { 230 struct gntdev_grant_map *map; 231 232 list_for_each_entry(map, &priv->maps, next) { 233 if (add->index + add->count < map->index) { 234 list_add_tail(&add->next, &map->next); 235 goto done; 236 } 237 add->index = map->index + map->count; 238 } 239 list_add_tail(&add->next, &priv->maps); 240 241 done: 242 gntdev_print_maps(priv, "[new]", add->index); 243 } 244 245 static struct gntdev_grant_map *gntdev_find_map_index(struct gntdev_priv *priv, 246 int index, int count) 247 { 248 struct gntdev_grant_map *map; 249 250 list_for_each_entry(map, &priv->maps, next) { 251 if (map->index != index) 252 continue; 253 if (count && map->count != count) 254 continue; 255 return map; 256 } 257 return NULL; 258 } 259 260 void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map) 261 { 262 if (!map) 263 return; 264 265 if (!refcount_dec_and_test(&map->users)) 266 return; 267 268 if (map->pages && !xen_pv_domain()) { 269 /* 270 * Increment the reference count. This ensures that the 271 * subsequent call to unmap_grant_pages() will not wind up 272 * re-entering itself. It *can* wind up calling 273 * gntdev_put_map() recursively, but such calls will be with a 274 * reference count greater than 1, so they will return before 275 * this code is reached. The recursion depth is thus limited to 276 * 1. Do NOT use refcount_inc() here, as it will detect that 277 * the reference count is zero and WARN(). 278 */ 279 refcount_set(&map->users, 1); 280 281 /* 282 * Unmap the grants. This may or may not be asynchronous, so it 283 * is possible that the reference count is 1 on return, but it 284 * could also be greater than 1. 285 */ 286 unmap_grant_pages(map, 0, map->count); 287 288 /* Check if the memory now needs to be freed */ 289 if (!refcount_dec_and_test(&map->users)) 290 return; 291 292 /* 293 * All pages have been returned to the hypervisor, so free the 294 * map. 295 */ 296 } 297 298 if (xen_pv_domain() && map->notifier_init) 299 mmu_interval_notifier_remove(&map->notifier); 300 301 if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) { 302 notify_remote_via_evtchn(map->notify.event); 303 evtchn_put(map->notify.event); 304 } 305 gntdev_free_map(map); 306 } 307 308 /* ------------------------------------------------------------------ */ 309 310 static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data) 311 { 312 struct gntdev_grant_map *map = data; 313 unsigned int pgnr = (addr - map->pages_vm_start) >> PAGE_SHIFT; 314 int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte | 315 (1 << _GNTMAP_guest_avail0); 316 u64 pte_maddr; 317 318 BUG_ON(pgnr >= map->count); 319 pte_maddr = arbitrary_virt_to_machine(pte).maddr; 320 321 gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags, 322 map->grants[pgnr].ref, 323 map->grants[pgnr].domid); 324 gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags, 325 INVALID_GRANT_HANDLE); 326 return 0; 327 } 328 329 int gntdev_map_grant_pages(struct gntdev_grant_map *map) 330 { 331 size_t alloced = 0; 332 int i, err = 0; 333 334 if (!xen_pv_domain()) { 335 /* Note: it could already be mapped */ 336 if (map->map_ops[0].handle != INVALID_GRANT_HANDLE) 337 return 0; 338 for (i = 0; i < map->count; i++) { 339 unsigned long addr = (unsigned long) 340 pfn_to_kaddr(page_to_pfn(map->pages[i])); 341 gnttab_set_map_op(&map->map_ops[i], addr, map->flags, 342 map->grants[i].ref, 343 map->grants[i].domid); 344 gnttab_set_unmap_op(&map->unmap_ops[i], addr, 345 map->flags, INVALID_GRANT_HANDLE); 346 } 347 } else { 348 /* 349 * Setup the map_ops corresponding to the pte entries pointing 350 * to the kernel linear addresses of the struct pages. 351 * These ptes are completely different from the user ptes dealt 352 * with find_grant_ptes. 353 * Note that GNTMAP_device_map isn't needed here: The 354 * dev_bus_addr output field gets consumed only from ->map_ops, 355 * and by not requesting it when mapping we also avoid needing 356 * to mirror dev_bus_addr into ->unmap_ops (and holding an extra 357 * reference to the page in the hypervisor). 358 */ 359 unsigned int flags = (map->flags & ~GNTMAP_device_map) | 360 GNTMAP_host_map; 361 362 for (i = 0; i < map->count; i++) { 363 unsigned long address = (unsigned long) 364 pfn_to_kaddr(page_to_pfn(map->pages[i])); 365 BUG_ON(PageHighMem(map->pages[i])); 366 367 gnttab_set_map_op(&map->kmap_ops[i], address, flags, 368 map->grants[i].ref, 369 map->grants[i].domid); 370 gnttab_set_unmap_op(&map->kunmap_ops[i], address, 371 flags, INVALID_GRANT_HANDLE); 372 } 373 } 374 375 pr_debug("map %d+%d\n", map->index, map->count); 376 err = gnttab_map_refs(map->map_ops, map->kmap_ops, map->pages, 377 map->count); 378 379 for (i = 0; i < map->count; i++) { 380 if (map->map_ops[i].status == GNTST_okay) { 381 map->unmap_ops[i].handle = map->map_ops[i].handle; 382 alloced++; 383 } else if (!err) 384 err = -EINVAL; 385 386 if (map->flags & GNTMAP_device_map) 387 map->unmap_ops[i].dev_bus_addr = map->map_ops[i].dev_bus_addr; 388 389 if (xen_pv_domain()) { 390 if (map->kmap_ops[i].status == GNTST_okay) { 391 alloced++; 392 map->kunmap_ops[i].handle = map->kmap_ops[i].handle; 393 } else if (!err) 394 err = -EINVAL; 395 } 396 } 397 atomic_add(alloced, &map->live_grants); 398 return err; 399 } 400 401 static void __unmap_grant_pages_done(int result, 402 struct gntab_unmap_queue_data *data) 403 { 404 unsigned int i; 405 struct gntdev_grant_map *map = data->data; 406 unsigned int offset = data->unmap_ops - map->unmap_ops; 407 int successful_unmaps = 0; 408 int live_grants; 409 410 for (i = 0; i < data->count; i++) { 411 if (map->unmap_ops[offset + i].status == GNTST_okay && 412 map->unmap_ops[offset + i].handle != INVALID_GRANT_HANDLE) 413 successful_unmaps++; 414 415 WARN_ON(map->unmap_ops[offset + i].status != GNTST_okay && 416 map->unmap_ops[offset + i].handle != INVALID_GRANT_HANDLE); 417 pr_debug("unmap handle=%d st=%d\n", 418 map->unmap_ops[offset+i].handle, 419 map->unmap_ops[offset+i].status); 420 map->unmap_ops[offset+i].handle = INVALID_GRANT_HANDLE; 421 if (xen_pv_domain()) { 422 if (map->kunmap_ops[offset + i].status == GNTST_okay && 423 map->kunmap_ops[offset + i].handle != INVALID_GRANT_HANDLE) 424 successful_unmaps++; 425 426 WARN_ON(map->kunmap_ops[offset + i].status != GNTST_okay && 427 map->kunmap_ops[offset + i].handle != INVALID_GRANT_HANDLE); 428 pr_debug("kunmap handle=%u st=%d\n", 429 map->kunmap_ops[offset+i].handle, 430 map->kunmap_ops[offset+i].status); 431 map->kunmap_ops[offset+i].handle = INVALID_GRANT_HANDLE; 432 } 433 } 434 435 /* 436 * Decrease the live-grant counter. This must happen after the loop to 437 * prevent premature reuse of the grants by gnttab_mmap(). 438 */ 439 live_grants = atomic_sub_return(successful_unmaps, &map->live_grants); 440 if (WARN_ON(live_grants < 0)) 441 pr_err("%s: live_grants became negative (%d) after unmapping %d pages!\n", 442 __func__, live_grants, successful_unmaps); 443 444 /* Release reference taken by __unmap_grant_pages */ 445 gntdev_put_map(NULL, map); 446 } 447 448 static void __unmap_grant_pages(struct gntdev_grant_map *map, int offset, 449 int pages) 450 { 451 if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) { 452 int pgno = (map->notify.addr >> PAGE_SHIFT); 453 454 if (pgno >= offset && pgno < offset + pages) { 455 /* No need for kmap, pages are in lowmem */ 456 uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno])); 457 458 tmp[map->notify.addr & (PAGE_SIZE-1)] = 0; 459 map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE; 460 } 461 } 462 463 map->unmap_data.unmap_ops = map->unmap_ops + offset; 464 map->unmap_data.kunmap_ops = xen_pv_domain() ? map->kunmap_ops + offset : NULL; 465 map->unmap_data.pages = map->pages + offset; 466 map->unmap_data.count = pages; 467 map->unmap_data.done = __unmap_grant_pages_done; 468 map->unmap_data.data = map; 469 refcount_inc(&map->users); /* to keep map alive during async call below */ 470 471 gnttab_unmap_refs_async(&map->unmap_data); 472 } 473 474 static void unmap_grant_pages(struct gntdev_grant_map *map, int offset, 475 int pages) 476 { 477 int range; 478 479 if (atomic_read(&map->live_grants) == 0) 480 return; /* Nothing to do */ 481 482 pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages); 483 484 /* It is possible the requested range will have a "hole" where we 485 * already unmapped some of the grants. Only unmap valid ranges. 486 */ 487 while (pages) { 488 while (pages && map->being_removed[offset]) { 489 offset++; 490 pages--; 491 } 492 range = 0; 493 while (range < pages) { 494 if (map->being_removed[offset + range]) 495 break; 496 map->being_removed[offset + range] = true; 497 range++; 498 } 499 if (range) 500 __unmap_grant_pages(map, offset, range); 501 offset += range; 502 pages -= range; 503 } 504 } 505 506 /* ------------------------------------------------------------------ */ 507 508 static void gntdev_vma_open(struct vm_area_struct *vma) 509 { 510 struct gntdev_grant_map *map = vma->vm_private_data; 511 512 pr_debug("gntdev_vma_open %p\n", vma); 513 refcount_inc(&map->users); 514 } 515 516 static void gntdev_vma_close(struct vm_area_struct *vma) 517 { 518 struct gntdev_grant_map *map = vma->vm_private_data; 519 struct file *file = vma->vm_file; 520 struct gntdev_priv *priv = file->private_data; 521 522 pr_debug("gntdev_vma_close %p\n", vma); 523 524 vma->vm_private_data = NULL; 525 gntdev_put_map(priv, map); 526 } 527 528 static struct page *gntdev_vma_find_special_page(struct vm_area_struct *vma, 529 unsigned long addr) 530 { 531 struct gntdev_grant_map *map = vma->vm_private_data; 532 533 return map->pages[(addr - map->pages_vm_start) >> PAGE_SHIFT]; 534 } 535 536 static const struct vm_operations_struct gntdev_vmops = { 537 .open = gntdev_vma_open, 538 .close = gntdev_vma_close, 539 .find_special_page = gntdev_vma_find_special_page, 540 }; 541 542 /* ------------------------------------------------------------------ */ 543 544 static bool gntdev_invalidate(struct mmu_interval_notifier *mn, 545 const struct mmu_notifier_range *range, 546 unsigned long cur_seq) 547 { 548 struct gntdev_grant_map *map = 549 container_of(mn, struct gntdev_grant_map, notifier); 550 unsigned long mstart, mend; 551 unsigned long map_start, map_end; 552 553 if (!mmu_notifier_range_blockable(range)) 554 return false; 555 556 map_start = map->pages_vm_start; 557 map_end = map->pages_vm_start + (map->count << PAGE_SHIFT); 558 559 /* 560 * If the VMA is split or otherwise changed the notifier is not 561 * updated, but we don't want to process VA's outside the modified 562 * VMA. FIXME: It would be much more understandable to just prevent 563 * modifying the VMA in the first place. 564 */ 565 if (map_start >= range->end || map_end <= range->start) 566 return true; 567 568 mstart = max(range->start, map_start); 569 mend = min(range->end, map_end); 570 pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n", 571 map->index, map->count, map_start, map_end, 572 range->start, range->end, mstart, mend); 573 unmap_grant_pages(map, (mstart - map_start) >> PAGE_SHIFT, 574 (mend - mstart) >> PAGE_SHIFT); 575 576 return true; 577 } 578 579 static const struct mmu_interval_notifier_ops gntdev_mmu_ops = { 580 .invalidate = gntdev_invalidate, 581 }; 582 583 /* ------------------------------------------------------------------ */ 584 585 static int gntdev_open(struct inode *inode, struct file *flip) 586 { 587 struct gntdev_priv *priv; 588 589 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 590 if (!priv) 591 return -ENOMEM; 592 593 INIT_LIST_HEAD(&priv->maps); 594 mutex_init(&priv->lock); 595 596 mutex_init(&priv->batch_lock); 597 598 #ifdef CONFIG_XEN_GNTDEV_DMABUF 599 priv->dmabuf_priv = gntdev_dmabuf_init(flip); 600 if (IS_ERR(priv->dmabuf_priv)) { 601 int ret = PTR_ERR(priv->dmabuf_priv); 602 603 kfree(priv); 604 return ret; 605 } 606 #endif 607 608 flip->private_data = priv; 609 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC 610 priv->dma_dev = gntdev_miscdev.this_device; 611 dma_coerce_mask_and_coherent(priv->dma_dev, DMA_BIT_MASK(64)); 612 #endif 613 pr_debug("priv %p\n", priv); 614 615 return 0; 616 } 617 618 static int gntdev_release(struct inode *inode, struct file *flip) 619 { 620 struct gntdev_priv *priv = flip->private_data; 621 struct gntdev_grant_map *map; 622 struct gntdev_copy_batch *batch; 623 624 pr_debug("priv %p\n", priv); 625 626 mutex_lock(&priv->lock); 627 while (!list_empty(&priv->maps)) { 628 map = list_entry(priv->maps.next, 629 struct gntdev_grant_map, next); 630 list_del(&map->next); 631 gntdev_put_map(NULL /* already removed */, map); 632 } 633 mutex_unlock(&priv->lock); 634 635 mutex_lock(&priv->batch_lock); 636 while (priv->batch) { 637 batch = priv->batch; 638 priv->batch = batch->next; 639 kfree(batch); 640 } 641 mutex_unlock(&priv->batch_lock); 642 643 #ifdef CONFIG_XEN_GNTDEV_DMABUF 644 gntdev_dmabuf_fini(priv->dmabuf_priv); 645 #endif 646 647 kfree(priv); 648 return 0; 649 } 650 651 static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv, 652 struct ioctl_gntdev_map_grant_ref __user *u) 653 { 654 struct ioctl_gntdev_map_grant_ref op; 655 struct gntdev_grant_map *map; 656 int err; 657 658 if (copy_from_user(&op, u, sizeof(op)) != 0) 659 return -EFAULT; 660 pr_debug("priv %p, add %d\n", priv, op.count); 661 if (unlikely(gntdev_test_page_count(op.count))) 662 return -EINVAL; 663 664 err = -ENOMEM; 665 map = gntdev_alloc_map(priv, op.count, 0 /* This is not a dma-buf. */); 666 if (!map) 667 return err; 668 669 if (copy_from_user(map->grants, &u->refs, 670 sizeof(map->grants[0]) * op.count) != 0) { 671 gntdev_put_map(NULL, map); 672 return -EFAULT; 673 } 674 675 mutex_lock(&priv->lock); 676 gntdev_add_map(priv, map); 677 op.index = map->index << PAGE_SHIFT; 678 mutex_unlock(&priv->lock); 679 680 if (copy_to_user(u, &op, sizeof(op)) != 0) 681 return -EFAULT; 682 683 return 0; 684 } 685 686 static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv, 687 struct ioctl_gntdev_unmap_grant_ref __user *u) 688 { 689 struct ioctl_gntdev_unmap_grant_ref op; 690 struct gntdev_grant_map *map; 691 int err = -ENOENT; 692 693 if (copy_from_user(&op, u, sizeof(op)) != 0) 694 return -EFAULT; 695 pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count); 696 697 mutex_lock(&priv->lock); 698 map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count); 699 if (map) { 700 list_del(&map->next); 701 err = 0; 702 } 703 mutex_unlock(&priv->lock); 704 if (map) 705 gntdev_put_map(priv, map); 706 return err; 707 } 708 709 static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv, 710 struct ioctl_gntdev_get_offset_for_vaddr __user *u) 711 { 712 struct ioctl_gntdev_get_offset_for_vaddr op; 713 struct vm_area_struct *vma; 714 struct gntdev_grant_map *map; 715 int rv = -EINVAL; 716 717 if (copy_from_user(&op, u, sizeof(op)) != 0) 718 return -EFAULT; 719 pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr); 720 721 mmap_read_lock(current->mm); 722 vma = find_vma(current->mm, op.vaddr); 723 if (!vma || vma->vm_ops != &gntdev_vmops) 724 goto out_unlock; 725 726 map = vma->vm_private_data; 727 if (!map) 728 goto out_unlock; 729 730 op.offset = map->index << PAGE_SHIFT; 731 op.count = map->count; 732 rv = 0; 733 734 out_unlock: 735 mmap_read_unlock(current->mm); 736 737 if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0) 738 return -EFAULT; 739 return rv; 740 } 741 742 static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u) 743 { 744 struct ioctl_gntdev_unmap_notify op; 745 struct gntdev_grant_map *map; 746 int rc; 747 int out_flags; 748 evtchn_port_t out_event; 749 750 if (copy_from_user(&op, u, sizeof(op))) 751 return -EFAULT; 752 753 if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT)) 754 return -EINVAL; 755 756 /* We need to grab a reference to the event channel we are going to use 757 * to send the notify before releasing the reference we may already have 758 * (if someone has called this ioctl twice). This is required so that 759 * it is possible to change the clear_byte part of the notification 760 * without disturbing the event channel part, which may now be the last 761 * reference to that event channel. 762 */ 763 if (op.action & UNMAP_NOTIFY_SEND_EVENT) { 764 if (evtchn_get(op.event_channel_port)) 765 return -EINVAL; 766 } 767 768 out_flags = op.action; 769 out_event = op.event_channel_port; 770 771 mutex_lock(&priv->lock); 772 773 list_for_each_entry(map, &priv->maps, next) { 774 uint64_t begin = map->index << PAGE_SHIFT; 775 uint64_t end = (map->index + map->count) << PAGE_SHIFT; 776 if (op.index >= begin && op.index < end) 777 goto found; 778 } 779 rc = -ENOENT; 780 goto unlock_out; 781 782 found: 783 if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) && 784 (map->flags & GNTMAP_readonly)) { 785 rc = -EINVAL; 786 goto unlock_out; 787 } 788 789 out_flags = map->notify.flags; 790 out_event = map->notify.event; 791 792 map->notify.flags = op.action; 793 map->notify.addr = op.index - (map->index << PAGE_SHIFT); 794 map->notify.event = op.event_channel_port; 795 796 rc = 0; 797 798 unlock_out: 799 mutex_unlock(&priv->lock); 800 801 /* Drop the reference to the event channel we did not save in the map */ 802 if (out_flags & UNMAP_NOTIFY_SEND_EVENT) 803 evtchn_put(out_event); 804 805 return rc; 806 } 807 808 static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt, 809 unsigned long *gfn) 810 { 811 unsigned long addr = (unsigned long)virt; 812 struct page *page; 813 unsigned long xen_pfn; 814 int ret; 815 816 ret = pin_user_pages_fast(addr, 1, batch->writeable ? FOLL_WRITE : 0, &page); 817 if (ret < 0) 818 return ret; 819 820 batch->pages[batch->nr_pages++] = page; 821 822 xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(addr & ~PAGE_MASK); 823 *gfn = pfn_to_gfn(xen_pfn); 824 825 return 0; 826 } 827 828 static void gntdev_put_pages(struct gntdev_copy_batch *batch) 829 { 830 unpin_user_pages_dirty_lock(batch->pages, batch->nr_pages, batch->writeable); 831 batch->nr_pages = 0; 832 batch->writeable = false; 833 } 834 835 static int gntdev_copy(struct gntdev_copy_batch *batch) 836 { 837 unsigned int i; 838 839 gnttab_batch_copy(batch->ops, batch->nr_ops); 840 gntdev_put_pages(batch); 841 842 /* 843 * For each completed op, update the status if the op failed 844 * and all previous ops for the segment were successful. 845 */ 846 for (i = 0; i < batch->nr_ops; i++) { 847 s16 status = batch->ops[i].status; 848 s16 old_status; 849 850 if (status == GNTST_okay) 851 continue; 852 853 if (__get_user(old_status, batch->status[i])) 854 return -EFAULT; 855 856 if (old_status != GNTST_okay) 857 continue; 858 859 if (__put_user(status, batch->status[i])) 860 return -EFAULT; 861 } 862 863 batch->nr_ops = 0; 864 return 0; 865 } 866 867 static int gntdev_grant_copy_seg(struct gntdev_copy_batch *batch, 868 struct gntdev_grant_copy_segment *seg, 869 s16 __user *status) 870 { 871 uint16_t copied = 0; 872 873 /* 874 * Disallow local -> local copies since there is only space in 875 * batch->pages for one page per-op and this would be a very 876 * expensive memcpy(). 877 */ 878 if (!(seg->flags & (GNTCOPY_source_gref | GNTCOPY_dest_gref))) 879 return -EINVAL; 880 881 /* Can't cross page if source/dest is a grant ref. */ 882 if (seg->flags & GNTCOPY_source_gref) { 883 if (seg->source.foreign.offset + seg->len > XEN_PAGE_SIZE) 884 return -EINVAL; 885 } 886 if (seg->flags & GNTCOPY_dest_gref) { 887 if (seg->dest.foreign.offset + seg->len > XEN_PAGE_SIZE) 888 return -EINVAL; 889 } 890 891 if (put_user(GNTST_okay, status)) 892 return -EFAULT; 893 894 while (copied < seg->len) { 895 struct gnttab_copy *op; 896 void __user *virt; 897 size_t len, off; 898 unsigned long gfn; 899 int ret; 900 901 if (batch->nr_ops >= GNTDEV_COPY_BATCH) { 902 ret = gntdev_copy(batch); 903 if (ret < 0) 904 return ret; 905 } 906 907 len = seg->len - copied; 908 909 op = &batch->ops[batch->nr_ops]; 910 op->flags = 0; 911 912 if (seg->flags & GNTCOPY_source_gref) { 913 op->source.u.ref = seg->source.foreign.ref; 914 op->source.domid = seg->source.foreign.domid; 915 op->source.offset = seg->source.foreign.offset + copied; 916 op->flags |= GNTCOPY_source_gref; 917 } else { 918 virt = seg->source.virt + copied; 919 off = (unsigned long)virt & ~XEN_PAGE_MASK; 920 len = min(len, (size_t)XEN_PAGE_SIZE - off); 921 batch->writeable = false; 922 923 ret = gntdev_get_page(batch, virt, &gfn); 924 if (ret < 0) 925 return ret; 926 927 op->source.u.gmfn = gfn; 928 op->source.domid = DOMID_SELF; 929 op->source.offset = off; 930 } 931 932 if (seg->flags & GNTCOPY_dest_gref) { 933 op->dest.u.ref = seg->dest.foreign.ref; 934 op->dest.domid = seg->dest.foreign.domid; 935 op->dest.offset = seg->dest.foreign.offset + copied; 936 op->flags |= GNTCOPY_dest_gref; 937 } else { 938 virt = seg->dest.virt + copied; 939 off = (unsigned long)virt & ~XEN_PAGE_MASK; 940 len = min(len, (size_t)XEN_PAGE_SIZE - off); 941 batch->writeable = true; 942 943 ret = gntdev_get_page(batch, virt, &gfn); 944 if (ret < 0) 945 return ret; 946 947 op->dest.u.gmfn = gfn; 948 op->dest.domid = DOMID_SELF; 949 op->dest.offset = off; 950 } 951 952 op->len = len; 953 copied += len; 954 955 batch->status[batch->nr_ops] = status; 956 batch->nr_ops++; 957 } 958 959 return 0; 960 } 961 962 static long gntdev_ioctl_grant_copy(struct gntdev_priv *priv, void __user *u) 963 { 964 struct ioctl_gntdev_grant_copy copy; 965 struct gntdev_copy_batch *batch; 966 unsigned int i; 967 int ret = 0; 968 969 if (copy_from_user(©, u, sizeof(copy))) 970 return -EFAULT; 971 972 mutex_lock(&priv->batch_lock); 973 if (!priv->batch) { 974 batch = kmalloc(sizeof(*batch), GFP_KERNEL); 975 } else { 976 batch = priv->batch; 977 priv->batch = batch->next; 978 } 979 mutex_unlock(&priv->batch_lock); 980 if (!batch) 981 return -ENOMEM; 982 983 batch->nr_ops = 0; 984 batch->nr_pages = 0; 985 986 for (i = 0; i < copy.count; i++) { 987 struct gntdev_grant_copy_segment seg; 988 989 if (copy_from_user(&seg, ©.segments[i], sizeof(seg))) { 990 ret = -EFAULT; 991 gntdev_put_pages(batch); 992 goto out; 993 } 994 995 ret = gntdev_grant_copy_seg(batch, &seg, ©.segments[i].status); 996 if (ret < 0) { 997 gntdev_put_pages(batch); 998 goto out; 999 } 1000 1001 cond_resched(); 1002 } 1003 if (batch->nr_ops) 1004 ret = gntdev_copy(batch); 1005 1006 out: 1007 mutex_lock(&priv->batch_lock); 1008 batch->next = priv->batch; 1009 priv->batch = batch; 1010 mutex_unlock(&priv->batch_lock); 1011 1012 return ret; 1013 } 1014 1015 static long gntdev_ioctl(struct file *flip, 1016 unsigned int cmd, unsigned long arg) 1017 { 1018 struct gntdev_priv *priv = flip->private_data; 1019 void __user *ptr = (void __user *)arg; 1020 1021 switch (cmd) { 1022 case IOCTL_GNTDEV_MAP_GRANT_REF: 1023 return gntdev_ioctl_map_grant_ref(priv, ptr); 1024 1025 case IOCTL_GNTDEV_UNMAP_GRANT_REF: 1026 return gntdev_ioctl_unmap_grant_ref(priv, ptr); 1027 1028 case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR: 1029 return gntdev_ioctl_get_offset_for_vaddr(priv, ptr); 1030 1031 case IOCTL_GNTDEV_SET_UNMAP_NOTIFY: 1032 return gntdev_ioctl_notify(priv, ptr); 1033 1034 case IOCTL_GNTDEV_GRANT_COPY: 1035 return gntdev_ioctl_grant_copy(priv, ptr); 1036 1037 #ifdef CONFIG_XEN_GNTDEV_DMABUF 1038 case IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS: 1039 return gntdev_ioctl_dmabuf_exp_from_refs(priv, ptr); 1040 1041 case IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED: 1042 return gntdev_ioctl_dmabuf_exp_wait_released(priv, ptr); 1043 1044 case IOCTL_GNTDEV_DMABUF_IMP_TO_REFS: 1045 return gntdev_ioctl_dmabuf_imp_to_refs(priv, ptr); 1046 1047 case IOCTL_GNTDEV_DMABUF_IMP_RELEASE: 1048 return gntdev_ioctl_dmabuf_imp_release(priv, ptr); 1049 #endif 1050 1051 default: 1052 pr_debug("priv %p, unknown cmd %x\n", priv, cmd); 1053 return -ENOIOCTLCMD; 1054 } 1055 1056 return 0; 1057 } 1058 1059 static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) 1060 { 1061 struct gntdev_priv *priv = flip->private_data; 1062 int index = vma->vm_pgoff; 1063 int count = vma_pages(vma); 1064 struct gntdev_grant_map *map; 1065 int err = -EINVAL; 1066 1067 if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED)) 1068 return -EINVAL; 1069 1070 pr_debug("map %d+%d at %lx (pgoff %lx)\n", 1071 index, count, vma->vm_start, vma->vm_pgoff); 1072 1073 mutex_lock(&priv->lock); 1074 map = gntdev_find_map_index(priv, index, count); 1075 if (!map) 1076 goto unlock_out; 1077 if (!atomic_add_unless(&map->in_use, 1, 1)) 1078 goto unlock_out; 1079 1080 refcount_inc(&map->users); 1081 1082 vma->vm_ops = &gntdev_vmops; 1083 1084 vm_flags_set(vma, VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP); 1085 1086 if (xen_pv_domain()) 1087 vm_flags_set(vma, VM_DONTCOPY); 1088 1089 vma->vm_private_data = map; 1090 if (map->flags) { 1091 if ((vma->vm_flags & VM_WRITE) && 1092 (map->flags & GNTMAP_readonly)) 1093 goto out_unlock_put; 1094 } else { 1095 map->flags = GNTMAP_host_map; 1096 if (!(vma->vm_flags & VM_WRITE)) 1097 map->flags |= GNTMAP_readonly; 1098 } 1099 1100 map->pages_vm_start = vma->vm_start; 1101 1102 if (xen_pv_domain()) { 1103 err = mmu_interval_notifier_insert_locked( 1104 &map->notifier, vma->vm_mm, vma->vm_start, 1105 vma->vm_end - vma->vm_start, &gntdev_mmu_ops); 1106 if (err) 1107 goto out_unlock_put; 1108 1109 map->notifier_init = true; 1110 } 1111 mutex_unlock(&priv->lock); 1112 1113 if (xen_pv_domain()) { 1114 /* 1115 * gntdev takes the address of the PTE in find_grant_ptes() and 1116 * passes it to the hypervisor in gntdev_map_grant_pages(). The 1117 * purpose of the notifier is to prevent the hypervisor pointer 1118 * to the PTE from going stale. 1119 * 1120 * Since this vma's mappings can't be touched without the 1121 * mmap_lock, and we are holding it now, there is no need for 1122 * the notifier_range locking pattern. 1123 */ 1124 mmu_interval_read_begin(&map->notifier); 1125 1126 err = apply_to_page_range(vma->vm_mm, vma->vm_start, 1127 vma->vm_end - vma->vm_start, 1128 find_grant_ptes, map); 1129 if (err) { 1130 pr_warn("find_grant_ptes() failure.\n"); 1131 goto out_put_map; 1132 } 1133 } 1134 1135 err = gntdev_map_grant_pages(map); 1136 if (err) 1137 goto out_put_map; 1138 1139 if (!xen_pv_domain()) { 1140 err = vm_map_pages_zero(vma, map->pages, map->count); 1141 if (err) 1142 goto out_put_map; 1143 } 1144 1145 return 0; 1146 1147 unlock_out: 1148 mutex_unlock(&priv->lock); 1149 return err; 1150 1151 out_unlock_put: 1152 mutex_unlock(&priv->lock); 1153 out_put_map: 1154 if (xen_pv_domain()) 1155 unmap_grant_pages(map, 0, map->count); 1156 gntdev_put_map(priv, map); 1157 return err; 1158 } 1159 1160 static const struct file_operations gntdev_fops = { 1161 .owner = THIS_MODULE, 1162 .open = gntdev_open, 1163 .release = gntdev_release, 1164 .mmap = gntdev_mmap, 1165 .unlocked_ioctl = gntdev_ioctl 1166 }; 1167 1168 static struct miscdevice gntdev_miscdev = { 1169 .minor = MISC_DYNAMIC_MINOR, 1170 .name = "xen/gntdev", 1171 .fops = &gntdev_fops, 1172 }; 1173 1174 /* ------------------------------------------------------------------ */ 1175 1176 static int __init gntdev_init(void) 1177 { 1178 int err; 1179 1180 if (!xen_domain()) 1181 return -ENODEV; 1182 1183 err = misc_register(&gntdev_miscdev); 1184 if (err != 0) { 1185 pr_err("Could not register gntdev device\n"); 1186 return err; 1187 } 1188 return 0; 1189 } 1190 1191 static void __exit gntdev_exit(void) 1192 { 1193 misc_deregister(&gntdev_miscdev); 1194 } 1195 1196 module_init(gntdev_init); 1197 module_exit(gntdev_exit); 1198 1199 /* ------------------------------------------------------------------ */ 1200