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