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