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