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/hmm.h> 44#include <linux/pagemap.h> 45 46#include <rdma/ib_umem_odp.h> 47 48#include "uverbs.h" 49 50static inline int ib_init_umem_odp(struct ib_umem_odp *umem_odp, 51 const struct mmu_interval_notifier_ops *ops) 52{ 53 int ret; 54 55 umem_odp->umem.is_odp = 1; 56 mutex_init(&umem_odp->umem_mutex); 57 58 if (!umem_odp->is_implicit_odp) { 59 size_t page_size = 1UL << umem_odp->page_shift; 60 unsigned long start; 61 unsigned long end; 62 size_t ndmas, npfns; 63 64 start = ALIGN_DOWN(umem_odp->umem.address, page_size); 65 if (check_add_overflow(umem_odp->umem.address, 66 (unsigned long)umem_odp->umem.length, 67 &end)) 68 return -EOVERFLOW; 69 end = ALIGN(end, page_size); 70 if (unlikely(end < page_size)) 71 return -EOVERFLOW; 72 73 ndmas = (end - start) >> umem_odp->page_shift; 74 if (!ndmas) 75 return -EINVAL; 76 77 npfns = (end - start) >> PAGE_SHIFT; 78 umem_odp->pfn_list = kvcalloc( 79 npfns, sizeof(*umem_odp->pfn_list), GFP_KERNEL); 80 if (!umem_odp->pfn_list) 81 return -ENOMEM; 82 83 umem_odp->dma_list = kvcalloc( 84 ndmas, sizeof(*umem_odp->dma_list), GFP_KERNEL); 85 if (!umem_odp->dma_list) { 86 ret = -ENOMEM; 87 goto out_pfn_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 99out_dma_list: 100 kvfree(umem_odp->dma_list); 101out_pfn_list: 102 kvfree(umem_odp->pfn_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 */ 116struct 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} 145EXPORT_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 * @ops: MMU interval ops, currently only @invalidate 156 */ 157struct ib_umem_odp * 158ib_umem_odp_alloc_child(struct ib_umem_odp *root, unsigned long addr, 159 size_t size, 160 const struct mmu_interval_notifier_ops *ops) 161{ 162 /* 163 * Caller must ensure that root cannot be freed during the call to 164 * ib_alloc_odp_umem. 165 */ 166 struct ib_umem_odp *odp_data; 167 struct ib_umem *umem; 168 int ret; 169 170 if (WARN_ON(!root->is_implicit_odp)) 171 return ERR_PTR(-EINVAL); 172 173 odp_data = kzalloc(sizeof(*odp_data), GFP_KERNEL); 174 if (!odp_data) 175 return ERR_PTR(-ENOMEM); 176 umem = &odp_data->umem; 177 umem->ibdev = root->umem.ibdev; 178 umem->length = size; 179 umem->address = addr; 180 umem->writable = root->umem.writable; 181 umem->owning_mm = root->umem.owning_mm; 182 odp_data->page_shift = PAGE_SHIFT; 183 odp_data->notifier.ops = ops; 184 185 /* 186 * A mmget must be held when registering a notifier, the owming_mm only 187 * has a mm_grab at this point. 188 */ 189 if (!mmget_not_zero(umem->owning_mm)) { 190 ret = -EFAULT; 191 goto out_free; 192 } 193 194 odp_data->tgid = get_pid(root->tgid); 195 ret = ib_init_umem_odp(odp_data, ops); 196 if (ret) 197 goto out_tgid; 198 mmput(umem->owning_mm); 199 return odp_data; 200 201out_tgid: 202 put_pid(odp_data->tgid); 203 mmput(umem->owning_mm); 204out_free: 205 kfree(odp_data); 206 return ERR_PTR(ret); 207} 208EXPORT_SYMBOL(ib_umem_odp_alloc_child); 209 210/** 211 * ib_umem_odp_get - Create a umem_odp for a userspace va 212 * 213 * @device: IB device struct to get UMEM 214 * @addr: userspace virtual address to start at 215 * @size: length of region to pin 216 * @access: IB_ACCESS_xxx flags for memory being pinned 217 * @ops: MMU interval ops, currently only @invalidate 218 * 219 * The driver should use when the access flags indicate ODP memory. It avoids 220 * pinning, instead, stores the mm for future page fault handling in 221 * conjunction with MMU notifiers. 222 */ 223struct ib_umem_odp *ib_umem_odp_get(struct ib_device *device, 224 unsigned long addr, size_t size, int access, 225 const struct mmu_interval_notifier_ops *ops) 226{ 227 struct ib_umem_odp *umem_odp; 228 int ret; 229 230 if (WARN_ON_ONCE(!(access & IB_ACCESS_ON_DEMAND))) 231 return ERR_PTR(-EINVAL); 232 233 umem_odp = kzalloc(sizeof(struct ib_umem_odp), GFP_KERNEL); 234 if (!umem_odp) 235 return ERR_PTR(-ENOMEM); 236 237 umem_odp->umem.ibdev = device; 238 umem_odp->umem.length = size; 239 umem_odp->umem.address = addr; 240 umem_odp->umem.writable = ib_access_writable(access); 241 umem_odp->umem.owning_mm = current->mm; 242 umem_odp->notifier.ops = ops; 243 244 umem_odp->page_shift = PAGE_SHIFT; 245#ifdef CONFIG_HUGETLB_PAGE 246 if (access & IB_ACCESS_HUGETLB) 247 umem_odp->page_shift = HPAGE_SHIFT; 248#endif 249 250 umem_odp->tgid = get_task_pid(current->group_leader, PIDTYPE_PID); 251 ret = ib_init_umem_odp(umem_odp, ops); 252 if (ret) 253 goto err_put_pid; 254 return umem_odp; 255 256err_put_pid: 257 put_pid(umem_odp->tgid); 258 kfree(umem_odp); 259 return ERR_PTR(ret); 260} 261EXPORT_SYMBOL(ib_umem_odp_get); 262 263void ib_umem_odp_release(struct ib_umem_odp *umem_odp) 264{ 265 /* 266 * Ensure that no more pages are mapped in the umem. 267 * 268 * It is the driver's responsibility to ensure, before calling us, 269 * that the hardware will not attempt to access the MR any more. 270 */ 271 if (!umem_odp->is_implicit_odp) { 272 mutex_lock(&umem_odp->umem_mutex); 273 ib_umem_odp_unmap_dma_pages(umem_odp, ib_umem_start(umem_odp), 274 ib_umem_end(umem_odp)); 275 mutex_unlock(&umem_odp->umem_mutex); 276 mmu_interval_notifier_remove(&umem_odp->notifier); 277 kvfree(umem_odp->dma_list); 278 kvfree(umem_odp->pfn_list); 279 } 280 put_pid(umem_odp->tgid); 281 kfree(umem_odp); 282} 283EXPORT_SYMBOL(ib_umem_odp_release); 284 285/* 286 * Map for DMA and insert a single page into the on-demand paging page tables. 287 * 288 * @umem: the umem to insert the page to. 289 * @dma_index: index in the umem to add the dma to. 290 * @page: the page struct to map and add. 291 * @access_mask: access permissions needed for this page. 292 * 293 * The function returns -EFAULT if the DMA mapping operation fails. 294 * 295 */ 296static int ib_umem_odp_map_dma_single_page( 297 struct ib_umem_odp *umem_odp, 298 unsigned int dma_index, 299 struct page *page, 300 u64 access_mask) 301{ 302 struct ib_device *dev = umem_odp->umem.ibdev; 303 dma_addr_t *dma_addr = &umem_odp->dma_list[dma_index]; 304 305 if (*dma_addr) { 306 /* 307 * If the page is already dma mapped it means it went through 308 * a non-invalidating trasition, like read-only to writable. 309 * Resync the flags. 310 */ 311 *dma_addr = (*dma_addr & ODP_DMA_ADDR_MASK) | access_mask; 312 return 0; 313 } 314 315 *dma_addr = ib_dma_map_page(dev, page, 0, 1 << umem_odp->page_shift, 316 DMA_BIDIRECTIONAL); 317 if (ib_dma_mapping_error(dev, *dma_addr)) { 318 *dma_addr = 0; 319 return -EFAULT; 320 } 321 umem_odp->npages++; 322 *dma_addr |= access_mask; 323 return 0; 324} 325 326/** 327 * ib_umem_odp_map_dma_and_lock - DMA map userspace memory in an ODP MR and lock it. 328 * 329 * Maps the range passed in the argument to DMA addresses. 330 * The DMA addresses of the mapped pages is updated in umem_odp->dma_list. 331 * Upon success the ODP MR will be locked to let caller complete its device 332 * page table update. 333 * 334 * Returns the number of pages mapped in success, negative error code 335 * for failure. 336 * @umem_odp: the umem to map and pin 337 * @user_virt: the address from which we need to map. 338 * @bcnt: the minimal number of bytes to pin and map. The mapping might be 339 * bigger due to alignment, and may also be smaller in case of an error 340 * pinning or mapping a page. The actual pages mapped is returned in 341 * the return value. 342 * @access_mask: bit mask of the requested access permissions for the given 343 * range. 344 * @fault: is faulting required for the given range 345 */ 346int ib_umem_odp_map_dma_and_lock(struct ib_umem_odp *umem_odp, u64 user_virt, 347 u64 bcnt, u64 access_mask, bool fault) 348 __acquires(&umem_odp->umem_mutex) 349{ 350 struct task_struct *owning_process = NULL; 351 struct mm_struct *owning_mm = umem_odp->umem.owning_mm; 352 int pfn_index, dma_index, ret = 0, start_idx; 353 unsigned int page_shift, hmm_order, pfn_start_idx; 354 unsigned long num_pfns, current_seq; 355 struct hmm_range range = {}; 356 unsigned long timeout; 357 358 if (access_mask == 0) 359 return -EINVAL; 360 361 if (user_virt < ib_umem_start(umem_odp) || 362 user_virt + bcnt > ib_umem_end(umem_odp)) 363 return -EFAULT; 364 365 page_shift = umem_odp->page_shift; 366 367 /* 368 * owning_process is allowed to be NULL, this means somehow the mm is 369 * existing beyond the lifetime of the originating process.. Presumably 370 * mmget_not_zero will fail in this case. 371 */ 372 owning_process = get_pid_task(umem_odp->tgid, PIDTYPE_PID); 373 if (!owning_process || !mmget_not_zero(owning_mm)) { 374 ret = -EINVAL; 375 goto out_put_task; 376 } 377 378 range.notifier = &umem_odp->notifier; 379 range.start = ALIGN_DOWN(user_virt, 1UL << page_shift); 380 range.end = ALIGN(user_virt + bcnt, 1UL << page_shift); 381 pfn_start_idx = (range.start - ib_umem_start(umem_odp)) >> PAGE_SHIFT; 382 num_pfns = (range.end - range.start) >> PAGE_SHIFT; 383 if (fault) { 384 range.default_flags = HMM_PFN_REQ_FAULT; 385 386 if (access_mask & ODP_WRITE_ALLOWED_BIT) 387 range.default_flags |= HMM_PFN_REQ_WRITE; 388 } 389 390 range.hmm_pfns = &(umem_odp->pfn_list[pfn_start_idx]); 391 timeout = jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT); 392 393retry: 394 current_seq = range.notifier_seq = 395 mmu_interval_read_begin(&umem_odp->notifier); 396 397 mmap_read_lock(owning_mm); 398 ret = hmm_range_fault(&range); 399 mmap_read_unlock(owning_mm); 400 if (unlikely(ret)) { 401 if (ret == -EBUSY && !time_after(jiffies, timeout)) 402 goto retry; 403 goto out_put_mm; 404 } 405 406 start_idx = (range.start - ib_umem_start(umem_odp)) >> page_shift; 407 dma_index = start_idx; 408 409 mutex_lock(&umem_odp->umem_mutex); 410 if (mmu_interval_read_retry(&umem_odp->notifier, current_seq)) { 411 mutex_unlock(&umem_odp->umem_mutex); 412 goto retry; 413 } 414 415 for (pfn_index = 0; pfn_index < num_pfns; 416 pfn_index += 1 << (page_shift - PAGE_SHIFT), dma_index++) { 417 418 if (fault) { 419 /* 420 * Since we asked for hmm_range_fault() to populate 421 * pages it shouldn't return an error entry on success. 422 */ 423 WARN_ON(range.hmm_pfns[pfn_index] & HMM_PFN_ERROR); 424 WARN_ON(!(range.hmm_pfns[pfn_index] & HMM_PFN_VALID)); 425 } else { 426 if (!(range.hmm_pfns[pfn_index] & HMM_PFN_VALID)) { 427 WARN_ON(umem_odp->dma_list[dma_index]); 428 continue; 429 } 430 access_mask = ODP_READ_ALLOWED_BIT; 431 if (range.hmm_pfns[pfn_index] & HMM_PFN_WRITE) 432 access_mask |= ODP_WRITE_ALLOWED_BIT; 433 } 434 435 hmm_order = hmm_pfn_to_map_order(range.hmm_pfns[pfn_index]); 436 /* If a hugepage was detected and ODP wasn't set for, the umem 437 * page_shift will be used, the opposite case is an error. 438 */ 439 if (hmm_order + PAGE_SHIFT < page_shift) { 440 ret = -EINVAL; 441 ibdev_dbg(umem_odp->umem.ibdev, 442 "%s: un-expected hmm_order %u, page_shift %u\n", 443 __func__, hmm_order, page_shift); 444 break; 445 } 446 447 ret = ib_umem_odp_map_dma_single_page( 448 umem_odp, dma_index, hmm_pfn_to_page(range.hmm_pfns[pfn_index]), 449 access_mask); 450 if (ret < 0) { 451 ibdev_dbg(umem_odp->umem.ibdev, 452 "ib_umem_odp_map_dma_single_page failed with error %d\n", ret); 453 break; 454 } 455 } 456 /* upon success lock should stay on hold for the callee */ 457 if (!ret) 458 ret = dma_index - start_idx; 459 else 460 mutex_unlock(&umem_odp->umem_mutex); 461 462out_put_mm: 463 mmput_async(owning_mm); 464out_put_task: 465 if (owning_process) 466 put_task_struct(owning_process); 467 return ret; 468} 469EXPORT_SYMBOL(ib_umem_odp_map_dma_and_lock); 470 471void ib_umem_odp_unmap_dma_pages(struct ib_umem_odp *umem_odp, u64 virt, 472 u64 bound) 473{ 474 dma_addr_t dma_addr; 475 dma_addr_t dma; 476 int idx; 477 u64 addr; 478 struct ib_device *dev = umem_odp->umem.ibdev; 479 480 lockdep_assert_held(&umem_odp->umem_mutex); 481 482 virt = max_t(u64, virt, ib_umem_start(umem_odp)); 483 bound = min_t(u64, bound, ib_umem_end(umem_odp)); 484 for (addr = virt; addr < bound; addr += BIT(umem_odp->page_shift)) { 485 idx = (addr - ib_umem_start(umem_odp)) >> umem_odp->page_shift; 486 dma = umem_odp->dma_list[idx]; 487 488 /* The access flags guaranteed a valid DMA address in case was NULL */ 489 if (dma) { 490 unsigned long pfn_idx = (addr - ib_umem_start(umem_odp)) >> PAGE_SHIFT; 491 struct page *page = hmm_pfn_to_page(umem_odp->pfn_list[pfn_idx]); 492 493 dma_addr = dma & ODP_DMA_ADDR_MASK; 494 ib_dma_unmap_page(dev, dma_addr, 495 BIT(umem_odp->page_shift), 496 DMA_BIDIRECTIONAL); 497 if (dma & ODP_WRITE_ALLOWED_BIT) { 498 struct page *head_page = compound_head(page); 499 /* 500 * set_page_dirty prefers being called with 501 * the page lock. However, MMU notifiers are 502 * called sometimes with and sometimes without 503 * the lock. We rely on the umem_mutex instead 504 * to prevent other mmu notifiers from 505 * continuing and allowing the page mapping to 506 * be removed. 507 */ 508 set_page_dirty(head_page); 509 } 510 umem_odp->dma_list[idx] = 0; 511 umem_odp->npages--; 512 } 513 } 514} 515EXPORT_SYMBOL(ib_umem_odp_unmap_dma_pages); 516