1 /* 2 * Copyright (c) 2014 Mellanox Technologies. All rights reserved. 3 * 4 * This software is available to you under a choice of one of two 5 * licenses. You may choose to be licensed under the terms of the GNU 6 * General Public License (GPL) Version 2, available from the file 7 * COPYING in the main directory of this source tree, or the 8 * OpenIB.org BSD license below: 9 * 10 * Redistribution and use in source and binary forms, with or 11 * without modification, are permitted provided that the following 12 * conditions are met: 13 * 14 * - Redistributions of source code must retain the above 15 * copyright notice, this list of conditions and the following 16 * disclaimer. 17 * 18 * - Redistributions in binary form must reproduce the above 19 * copyright notice, this list of conditions and the following 20 * disclaimer in the documentation and/or other materials 21 * provided with the distribution. 22 * 23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS 27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 30 * SOFTWARE. 31 */ 32 33 #include <linux/types.h> 34 #include <linux/sched.h> 35 #include <linux/sched/mm.h> 36 #include <linux/sched/task.h> 37 #include <linux/pid.h> 38 #include <linux/slab.h> 39 #include <linux/export.h> 40 #include <linux/vmalloc.h> 41 #include <linux/hugetlb.h> 42 #include <linux/interval_tree.h> 43 #include <linux/pagemap.h> 44 45 #include <rdma/ib_verbs.h> 46 #include <rdma/ib_umem.h> 47 #include <rdma/ib_umem_odp.h> 48 49 #include "uverbs.h" 50 51 static inline int ib_init_umem_odp(struct ib_umem_odp *umem_odp, 52 const struct mmu_interval_notifier_ops *ops) 53 { 54 int ret; 55 56 umem_odp->umem.is_odp = 1; 57 mutex_init(&umem_odp->umem_mutex); 58 59 if (!umem_odp->is_implicit_odp) { 60 size_t page_size = 1UL << umem_odp->page_shift; 61 unsigned long start; 62 unsigned long end; 63 size_t pages; 64 65 start = ALIGN_DOWN(umem_odp->umem.address, page_size); 66 if (check_add_overflow(umem_odp->umem.address, 67 (unsigned long)umem_odp->umem.length, 68 &end)) 69 return -EOVERFLOW; 70 end = ALIGN(end, page_size); 71 if (unlikely(end < page_size)) 72 return -EOVERFLOW; 73 74 pages = (end - start) >> umem_odp->page_shift; 75 if (!pages) 76 return -EINVAL; 77 78 umem_odp->page_list = kvcalloc( 79 pages, sizeof(*umem_odp->page_list), GFP_KERNEL); 80 if (!umem_odp->page_list) 81 return -ENOMEM; 82 83 umem_odp->dma_list = kvcalloc( 84 pages, sizeof(*umem_odp->dma_list), GFP_KERNEL); 85 if (!umem_odp->dma_list) { 86 ret = -ENOMEM; 87 goto out_page_list; 88 } 89 90 ret = mmu_interval_notifier_insert(&umem_odp->notifier, 91 umem_odp->umem.owning_mm, 92 start, end - start, ops); 93 if (ret) 94 goto out_dma_list; 95 } 96 97 return 0; 98 99 out_dma_list: 100 kvfree(umem_odp->dma_list); 101 out_page_list: 102 kvfree(umem_odp->page_list); 103 return ret; 104 } 105 106 /** 107 * ib_umem_odp_alloc_implicit - Allocate a parent implicit ODP umem 108 * 109 * Implicit ODP umems do not have a VA range and do not have any page lists. 110 * They exist only to hold the per_mm reference to help the driver create 111 * children umems. 112 * 113 * @device: IB device to create UMEM 114 * @access: ib_reg_mr access flags 115 */ 116 struct ib_umem_odp *ib_umem_odp_alloc_implicit(struct ib_device *device, 117 int access) 118 { 119 struct ib_umem *umem; 120 struct ib_umem_odp *umem_odp; 121 int ret; 122 123 if (access & IB_ACCESS_HUGETLB) 124 return ERR_PTR(-EINVAL); 125 126 umem_odp = kzalloc(sizeof(*umem_odp), GFP_KERNEL); 127 if (!umem_odp) 128 return ERR_PTR(-ENOMEM); 129 umem = &umem_odp->umem; 130 umem->ibdev = device; 131 umem->writable = ib_access_writable(access); 132 umem->owning_mm = current->mm; 133 umem_odp->is_implicit_odp = 1; 134 umem_odp->page_shift = PAGE_SHIFT; 135 136 umem_odp->tgid = get_task_pid(current->group_leader, PIDTYPE_PID); 137 ret = ib_init_umem_odp(umem_odp, NULL); 138 if (ret) { 139 put_pid(umem_odp->tgid); 140 kfree(umem_odp); 141 return ERR_PTR(ret); 142 } 143 return umem_odp; 144 } 145 EXPORT_SYMBOL(ib_umem_odp_alloc_implicit); 146 147 /** 148 * ib_umem_odp_alloc_child - Allocate a child ODP umem under an implicit 149 * parent ODP umem 150 * 151 * @root: The parent umem enclosing the child. This must be allocated using 152 * ib_alloc_implicit_odp_umem() 153 * @addr: The starting userspace VA 154 * @size: The length of the userspace VA 155 */ 156 struct ib_umem_odp * 157 ib_umem_odp_alloc_child(struct ib_umem_odp *root, unsigned long addr, 158 size_t size, 159 const struct mmu_interval_notifier_ops *ops) 160 { 161 /* 162 * Caller must ensure that root cannot be freed during the call to 163 * ib_alloc_odp_umem. 164 */ 165 struct ib_umem_odp *odp_data; 166 struct ib_umem *umem; 167 int ret; 168 169 if (WARN_ON(!root->is_implicit_odp)) 170 return ERR_PTR(-EINVAL); 171 172 odp_data = kzalloc(sizeof(*odp_data), GFP_KERNEL); 173 if (!odp_data) 174 return ERR_PTR(-ENOMEM); 175 umem = &odp_data->umem; 176 umem->ibdev = root->umem.ibdev; 177 umem->length = size; 178 umem->address = addr; 179 umem->writable = root->umem.writable; 180 umem->owning_mm = root->umem.owning_mm; 181 odp_data->page_shift = PAGE_SHIFT; 182 odp_data->notifier.ops = ops; 183 184 /* 185 * A mmget must be held when registering a notifier, the owming_mm only 186 * has a mm_grab at this point. 187 */ 188 if (!mmget_not_zero(umem->owning_mm)) { 189 ret = -EFAULT; 190 goto out_free; 191 } 192 193 odp_data->tgid = get_pid(root->tgid); 194 ret = ib_init_umem_odp(odp_data, ops); 195 if (ret) 196 goto out_tgid; 197 mmput(umem->owning_mm); 198 return odp_data; 199 200 out_tgid: 201 put_pid(odp_data->tgid); 202 mmput(umem->owning_mm); 203 out_free: 204 kfree(odp_data); 205 return ERR_PTR(ret); 206 } 207 EXPORT_SYMBOL(ib_umem_odp_alloc_child); 208 209 /** 210 * ib_umem_odp_get - Create a umem_odp for a userspace va 211 * 212 * @device: IB device struct to get UMEM 213 * @addr: userspace virtual address to start at 214 * @size: length of region to pin 215 * @access: IB_ACCESS_xxx flags for memory being pinned 216 * 217 * The driver should use when the access flags indicate ODP memory. It avoids 218 * pinning, instead, stores the mm for future page fault handling in 219 * conjunction with MMU notifiers. 220 */ 221 struct ib_umem_odp *ib_umem_odp_get(struct ib_device *device, 222 unsigned long addr, size_t size, int access, 223 const struct mmu_interval_notifier_ops *ops) 224 { 225 struct ib_umem_odp *umem_odp; 226 struct mm_struct *mm; 227 int ret; 228 229 if (WARN_ON_ONCE(!(access & IB_ACCESS_ON_DEMAND))) 230 return ERR_PTR(-EINVAL); 231 232 umem_odp = kzalloc(sizeof(struct ib_umem_odp), GFP_KERNEL); 233 if (!umem_odp) 234 return ERR_PTR(-ENOMEM); 235 236 umem_odp->umem.ibdev = device; 237 umem_odp->umem.length = size; 238 umem_odp->umem.address = addr; 239 umem_odp->umem.writable = ib_access_writable(access); 240 umem_odp->umem.owning_mm = mm = current->mm; 241 umem_odp->notifier.ops = ops; 242 243 umem_odp->page_shift = PAGE_SHIFT; 244 #ifdef CONFIG_HUGETLB_PAGE 245 if (access & IB_ACCESS_HUGETLB) 246 umem_odp->page_shift = HPAGE_SHIFT; 247 #endif 248 249 umem_odp->tgid = get_task_pid(current->group_leader, PIDTYPE_PID); 250 ret = ib_init_umem_odp(umem_odp, ops); 251 if (ret) 252 goto err_put_pid; 253 return umem_odp; 254 255 err_put_pid: 256 put_pid(umem_odp->tgid); 257 kfree(umem_odp); 258 return ERR_PTR(ret); 259 } 260 EXPORT_SYMBOL(ib_umem_odp_get); 261 262 void ib_umem_odp_release(struct ib_umem_odp *umem_odp) 263 { 264 /* 265 * Ensure that no more pages are mapped in the umem. 266 * 267 * It is the driver's responsibility to ensure, before calling us, 268 * that the hardware will not attempt to access the MR any more. 269 */ 270 if (!umem_odp->is_implicit_odp) { 271 mutex_lock(&umem_odp->umem_mutex); 272 ib_umem_odp_unmap_dma_pages(umem_odp, ib_umem_start(umem_odp), 273 ib_umem_end(umem_odp)); 274 mutex_unlock(&umem_odp->umem_mutex); 275 mmu_interval_notifier_remove(&umem_odp->notifier); 276 kvfree(umem_odp->dma_list); 277 kvfree(umem_odp->page_list); 278 } 279 put_pid(umem_odp->tgid); 280 kfree(umem_odp); 281 } 282 EXPORT_SYMBOL(ib_umem_odp_release); 283 284 /* 285 * Map for DMA and insert a single page into the on-demand paging page tables. 286 * 287 * @umem: the umem to insert the page to. 288 * @page_index: index in the umem to add the page to. 289 * @page: the page struct to map and add. 290 * @access_mask: access permissions needed for this page. 291 * @current_seq: sequence number for synchronization with invalidations. 292 * the sequence number is taken from 293 * umem_odp->notifiers_seq. 294 * 295 * The function returns -EFAULT if the DMA mapping operation fails. It returns 296 * -EAGAIN if a concurrent invalidation prevents us from updating the page. 297 * 298 * The page is released via put_page even if the operation failed. For on-demand 299 * pinning, the page is released whenever it isn't stored in the umem. 300 */ 301 static int ib_umem_odp_map_dma_single_page( 302 struct ib_umem_odp *umem_odp, 303 unsigned int page_index, 304 struct page *page, 305 u64 access_mask, 306 unsigned long current_seq) 307 { 308 struct ib_device *dev = umem_odp->umem.ibdev; 309 dma_addr_t dma_addr; 310 int ret = 0; 311 312 if (mmu_interval_check_retry(&umem_odp->notifier, current_seq)) { 313 ret = -EAGAIN; 314 goto out; 315 } 316 if (!(umem_odp->dma_list[page_index])) { 317 dma_addr = 318 ib_dma_map_page(dev, page, 0, BIT(umem_odp->page_shift), 319 DMA_BIDIRECTIONAL); 320 if (ib_dma_mapping_error(dev, dma_addr)) { 321 ret = -EFAULT; 322 goto out; 323 } 324 umem_odp->dma_list[page_index] = dma_addr | access_mask; 325 umem_odp->page_list[page_index] = page; 326 umem_odp->npages++; 327 } else if (umem_odp->page_list[page_index] == page) { 328 umem_odp->dma_list[page_index] |= access_mask; 329 } else { 330 /* 331 * This is a race here where we could have done: 332 * 333 * CPU0 CPU1 334 * get_user_pages() 335 * invalidate() 336 * page_fault() 337 * mutex_lock(umem_mutex) 338 * page from GUP != page in ODP 339 * 340 * It should be prevented by the retry test above as reading 341 * the seq number should be reliable under the 342 * umem_mutex. Thus something is really not working right if 343 * things get here. 344 */ 345 WARN(true, 346 "Got different pages in IB device and from get_user_pages. IB device page: %p, gup page: %p\n", 347 umem_odp->page_list[page_index], page); 348 ret = -EAGAIN; 349 } 350 351 out: 352 put_page(page); 353 return ret; 354 } 355 356 /** 357 * ib_umem_odp_map_dma_pages - Pin and DMA map userspace memory in an ODP MR. 358 * 359 * Pins the range of pages passed in the argument, and maps them to 360 * DMA addresses. The DMA addresses of the mapped pages is updated in 361 * umem_odp->dma_list. 362 * 363 * Returns the number of pages mapped in success, negative error code 364 * for failure. 365 * An -EAGAIN error code is returned when a concurrent mmu notifier prevents 366 * the function from completing its task. 367 * An -ENOENT error code indicates that userspace process is being terminated 368 * and mm was already destroyed. 369 * @umem_odp: the umem to map and pin 370 * @user_virt: the address from which we need to map. 371 * @bcnt: the minimal number of bytes to pin and map. The mapping might be 372 * bigger due to alignment, and may also be smaller in case of an error 373 * pinning or mapping a page. The actual pages mapped is returned in 374 * the return value. 375 * @access_mask: bit mask of the requested access permissions for the given 376 * range. 377 * @current_seq: the MMU notifiers sequance value for synchronization with 378 * invalidations. the sequance number is read from 379 * umem_odp->notifiers_seq before calling this function 380 */ 381 int ib_umem_odp_map_dma_pages(struct ib_umem_odp *umem_odp, u64 user_virt, 382 u64 bcnt, u64 access_mask, 383 unsigned long current_seq) 384 { 385 struct task_struct *owning_process = NULL; 386 struct mm_struct *owning_mm = umem_odp->umem.owning_mm; 387 struct page **local_page_list = NULL; 388 u64 page_mask, off; 389 int j, k, ret = 0, start_idx, npages = 0; 390 unsigned int flags = 0, page_shift; 391 phys_addr_t p = 0; 392 393 if (access_mask == 0) 394 return -EINVAL; 395 396 if (user_virt < ib_umem_start(umem_odp) || 397 user_virt + bcnt > ib_umem_end(umem_odp)) 398 return -EFAULT; 399 400 local_page_list = (struct page **)__get_free_page(GFP_KERNEL); 401 if (!local_page_list) 402 return -ENOMEM; 403 404 page_shift = umem_odp->page_shift; 405 page_mask = ~(BIT(page_shift) - 1); 406 off = user_virt & (~page_mask); 407 user_virt = user_virt & page_mask; 408 bcnt += off; /* Charge for the first page offset as well. */ 409 410 /* 411 * owning_process is allowed to be NULL, this means somehow the mm is 412 * existing beyond the lifetime of the originating process.. Presumably 413 * mmget_not_zero will fail in this case. 414 */ 415 owning_process = get_pid_task(umem_odp->tgid, PIDTYPE_PID); 416 if (!owning_process || !mmget_not_zero(owning_mm)) { 417 ret = -EINVAL; 418 goto out_put_task; 419 } 420 421 if (access_mask & ODP_WRITE_ALLOWED_BIT) 422 flags |= FOLL_WRITE; 423 424 start_idx = (user_virt - ib_umem_start(umem_odp)) >> page_shift; 425 k = start_idx; 426 427 while (bcnt > 0) { 428 const size_t gup_num_pages = min_t(size_t, 429 ALIGN(bcnt, PAGE_SIZE) / PAGE_SIZE, 430 PAGE_SIZE / sizeof(struct page *)); 431 432 down_read(&owning_mm->mmap_sem); 433 /* 434 * Note: this might result in redundent page getting. We can 435 * avoid this by checking dma_list to be 0 before calling 436 * get_user_pages. However, this make the code much more 437 * complex (and doesn't gain us much performance in most use 438 * cases). 439 */ 440 npages = get_user_pages_remote(owning_process, owning_mm, 441 user_virt, gup_num_pages, 442 flags, local_page_list, NULL, NULL); 443 up_read(&owning_mm->mmap_sem); 444 445 if (npages < 0) { 446 if (npages != -EAGAIN) 447 pr_warn("fail to get %zu user pages with error %d\n", gup_num_pages, npages); 448 else 449 pr_debug("fail to get %zu user pages with error %d\n", gup_num_pages, npages); 450 break; 451 } 452 453 bcnt -= min_t(size_t, npages << PAGE_SHIFT, bcnt); 454 mutex_lock(&umem_odp->umem_mutex); 455 for (j = 0; j < npages; j++, user_virt += PAGE_SIZE) { 456 if (user_virt & ~page_mask) { 457 p += PAGE_SIZE; 458 if (page_to_phys(local_page_list[j]) != p) { 459 ret = -EFAULT; 460 break; 461 } 462 put_page(local_page_list[j]); 463 continue; 464 } 465 466 ret = ib_umem_odp_map_dma_single_page( 467 umem_odp, k, local_page_list[j], 468 access_mask, current_seq); 469 if (ret < 0) { 470 if (ret != -EAGAIN) 471 pr_warn("ib_umem_odp_map_dma_single_page failed with error %d\n", ret); 472 else 473 pr_debug("ib_umem_odp_map_dma_single_page failed with error %d\n", ret); 474 break; 475 } 476 477 p = page_to_phys(local_page_list[j]); 478 k++; 479 } 480 mutex_unlock(&umem_odp->umem_mutex); 481 482 if (ret < 0) { 483 /* 484 * Release pages, remembering that the first page 485 * to hit an error was already released by 486 * ib_umem_odp_map_dma_single_page(). 487 */ 488 if (npages - (j + 1) > 0) 489 release_pages(&local_page_list[j+1], 490 npages - (j + 1)); 491 break; 492 } 493 } 494 495 if (ret >= 0) { 496 if (npages < 0 && k == start_idx) 497 ret = npages; 498 else 499 ret = k - start_idx; 500 } 501 502 mmput(owning_mm); 503 out_put_task: 504 if (owning_process) 505 put_task_struct(owning_process); 506 free_page((unsigned long)local_page_list); 507 return ret; 508 } 509 EXPORT_SYMBOL(ib_umem_odp_map_dma_pages); 510 511 void ib_umem_odp_unmap_dma_pages(struct ib_umem_odp *umem_odp, u64 virt, 512 u64 bound) 513 { 514 int idx; 515 u64 addr; 516 struct ib_device *dev = umem_odp->umem.ibdev; 517 518 lockdep_assert_held(&umem_odp->umem_mutex); 519 520 virt = max_t(u64, virt, ib_umem_start(umem_odp)); 521 bound = min_t(u64, bound, ib_umem_end(umem_odp)); 522 /* Note that during the run of this function, the 523 * notifiers_count of the MR is > 0, preventing any racing 524 * faults from completion. We might be racing with other 525 * invalidations, so we must make sure we free each page only 526 * once. */ 527 for (addr = virt; addr < bound; addr += BIT(umem_odp->page_shift)) { 528 idx = (addr - ib_umem_start(umem_odp)) >> umem_odp->page_shift; 529 if (umem_odp->page_list[idx]) { 530 struct page *page = umem_odp->page_list[idx]; 531 dma_addr_t dma = umem_odp->dma_list[idx]; 532 dma_addr_t dma_addr = dma & ODP_DMA_ADDR_MASK; 533 534 WARN_ON(!dma_addr); 535 536 ib_dma_unmap_page(dev, dma_addr, 537 BIT(umem_odp->page_shift), 538 DMA_BIDIRECTIONAL); 539 if (dma & ODP_WRITE_ALLOWED_BIT) { 540 struct page *head_page = compound_head(page); 541 /* 542 * set_page_dirty prefers being called with 543 * the page lock. However, MMU notifiers are 544 * called sometimes with and sometimes without 545 * the lock. We rely on the umem_mutex instead 546 * to prevent other mmu notifiers from 547 * continuing and allowing the page mapping to 548 * be removed. 549 */ 550 set_page_dirty(head_page); 551 } 552 umem_odp->page_list[idx] = NULL; 553 umem_odp->dma_list[idx] = 0; 554 umem_odp->npages--; 555 } 556 } 557 } 558 EXPORT_SYMBOL(ib_umem_odp_unmap_dma_pages); 559