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/hmm-dma.h>
45#include <linux/pagemap.h>
46
47#include <rdma/ib_umem_odp.h>
48
49#include "uverbs.h"
50
51static void ib_init_umem_implicit_odp(struct ib_umem_odp *umem_odp)
52{
53 umem_odp->is_implicit_odp = 1;
54 umem_odp->umem.is_odp = 1;
55 mutex_init(&umem_odp->umem_mutex);
56}
57
58static int ib_init_umem_odp(struct ib_umem_odp *umem_odp,
59 const struct mmu_interval_notifier_ops *ops)
60{
61 struct ib_device *dev = umem_odp->umem.ibdev;
62 size_t page_size = 1UL << umem_odp->page_shift;
63 struct hmm_dma_map *map;
64 unsigned long start;
65 unsigned long end;
66 size_t nr_entries;
67 int ret = 0;
68
69 umem_odp->umem.is_odp = 1;
70 mutex_init(&umem_odp->umem_mutex);
71
72 start = ALIGN_DOWN(umem_odp->umem.address, page_size);
73 if (check_add_overflow(umem_odp->umem.address,
74 (unsigned long)umem_odp->umem.length, &end))
75 return -EOVERFLOW;
76 end = ALIGN(end, page_size);
77 if (unlikely(end < page_size))
78 return -EOVERFLOW;
79 /*
80 * The mmu notifier can be called within reclaim contexts and takes the
81 * umem_mutex. This is rare to trigger in testing, teach lockdep about
82 * it.
83 */
84 if (IS_ENABLED(CONFIG_LOCKDEP)) {
85 fs_reclaim_acquire(GFP_KERNEL);
86 mutex_lock(&umem_odp->umem_mutex);
87 mutex_unlock(lock: &umem_odp->umem_mutex);
88 fs_reclaim_release(GFP_KERNEL);
89 }
90
91 nr_entries = (end - start) >> PAGE_SHIFT;
92 if (!(nr_entries * PAGE_SIZE / page_size))
93 return -EINVAL;
94
95 map = &umem_odp->map;
96 if (ib_uses_virt_dma(dev)) {
97 map->pfn_list = kvcalloc(nr_entries, sizeof(*map->pfn_list),
98 GFP_KERNEL | __GFP_NOWARN);
99 if (!map->pfn_list)
100 ret = -ENOMEM;
101 } else
102 ret = hmm_dma_map_alloc(dev: dev->dma_device, map,
103 nr_entries: (end - start) >> PAGE_SHIFT,
104 dma_entry_size: 1 << umem_odp->page_shift);
105 if (ret)
106 return ret;
107
108 ret = mmu_interval_notifier_insert(interval_sub: &umem_odp->notifier,
109 mm: umem_odp->umem.owning_mm, start,
110 length: end - start, ops);
111 if (ret)
112 goto out_free_map;
113
114 return 0;
115
116out_free_map:
117 if (ib_uses_virt_dma(dev))
118 kvfree(addr: map->pfn_list);
119 else
120 hmm_dma_map_free(dev: dev->dma_device, map);
121 return ret;
122}
123
124/**
125 * ib_umem_odp_alloc_implicit - Allocate a parent implicit ODP umem
126 *
127 * Implicit ODP umems do not have a VA range and do not have any page lists.
128 * They exist only to hold the per_mm reference to help the driver create
129 * children umems.
130 *
131 * @device: IB device to create UMEM
132 * @access: ib_reg_mr access flags
133 */
134struct ib_umem_odp *ib_umem_odp_alloc_implicit(struct ib_device *device,
135 int access)
136{
137 struct ib_umem *umem;
138 struct ib_umem_odp *umem_odp;
139
140 if (access & IB_ACCESS_HUGETLB)
141 return ERR_PTR(error: -EINVAL);
142
143 umem_odp = kzalloc(sizeof(*umem_odp), GFP_KERNEL);
144 if (!umem_odp)
145 return ERR_PTR(error: -ENOMEM);
146 umem = &umem_odp->umem;
147 umem->ibdev = device;
148 umem->writable = ib_access_writable(access_flags: access);
149 umem->owning_mm = current->mm;
150 umem_odp->page_shift = PAGE_SHIFT;
151
152 umem_odp->tgid = get_task_pid(current->group_leader, type: PIDTYPE_PID);
153 ib_init_umem_implicit_odp(umem_odp);
154 return umem_odp;
155}
156EXPORT_SYMBOL(ib_umem_odp_alloc_implicit);
157
158/**
159 * ib_umem_odp_alloc_child - Allocate a child ODP umem under an implicit
160 * parent ODP umem
161 *
162 * @root: The parent umem enclosing the child. This must be allocated using
163 * ib_alloc_implicit_odp_umem()
164 * @addr: The starting userspace VA
165 * @size: The length of the userspace VA
166 * @ops: MMU interval ops, currently only @invalidate
167 */
168struct ib_umem_odp *
169ib_umem_odp_alloc_child(struct ib_umem_odp *root, unsigned long addr,
170 size_t size,
171 const struct mmu_interval_notifier_ops *ops)
172{
173 /*
174 * Caller must ensure that root cannot be freed during the call to
175 * ib_alloc_odp_umem.
176 */
177 struct ib_umem_odp *odp_data;
178 struct ib_umem *umem;
179 int ret;
180
181 if (WARN_ON(!root->is_implicit_odp))
182 return ERR_PTR(error: -EINVAL);
183
184 odp_data = kzalloc(sizeof(*odp_data), GFP_KERNEL);
185 if (!odp_data)
186 return ERR_PTR(error: -ENOMEM);
187 umem = &odp_data->umem;
188 umem->ibdev = root->umem.ibdev;
189 umem->length = size;
190 umem->address = addr;
191 umem->writable = root->umem.writable;
192 umem->owning_mm = root->umem.owning_mm;
193 odp_data->page_shift = PAGE_SHIFT;
194 odp_data->notifier.ops = ops;
195
196 /*
197 * A mmget must be held when registering a notifier, the owming_mm only
198 * has a mm_grab at this point.
199 */
200 if (!mmget_not_zero(mm: umem->owning_mm)) {
201 ret = -EFAULT;
202 goto out_free;
203 }
204
205 odp_data->tgid = get_pid(pid: root->tgid);
206 ret = ib_init_umem_odp(umem_odp: odp_data, ops);
207 if (ret)
208 goto out_tgid;
209 mmput(umem->owning_mm);
210 return odp_data;
211
212out_tgid:
213 put_pid(pid: odp_data->tgid);
214 mmput(umem->owning_mm);
215out_free:
216 kfree(objp: odp_data);
217 return ERR_PTR(error: ret);
218}
219EXPORT_SYMBOL(ib_umem_odp_alloc_child);
220
221/**
222 * ib_umem_odp_get - Create a umem_odp for a userspace va
223 *
224 * @device: IB device struct to get UMEM
225 * @addr: userspace virtual address to start at
226 * @size: length of region to pin
227 * @access: IB_ACCESS_xxx flags for memory being pinned
228 * @ops: MMU interval ops, currently only @invalidate
229 *
230 * The driver should use when the access flags indicate ODP memory. It avoids
231 * pinning, instead, stores the mm for future page fault handling in
232 * conjunction with MMU notifiers.
233 */
234struct ib_umem_odp *ib_umem_odp_get(struct ib_device *device,
235 unsigned long addr, size_t size, int access,
236 const struct mmu_interval_notifier_ops *ops)
237{
238 struct ib_umem_odp *umem_odp;
239 int ret;
240
241 if (WARN_ON_ONCE(!(access & IB_ACCESS_ON_DEMAND)))
242 return ERR_PTR(error: -EINVAL);
243
244 umem_odp = kzalloc(sizeof(struct ib_umem_odp), GFP_KERNEL);
245 if (!umem_odp)
246 return ERR_PTR(error: -ENOMEM);
247
248 umem_odp->umem.ibdev = device;
249 umem_odp->umem.length = size;
250 umem_odp->umem.address = addr;
251 umem_odp->umem.writable = ib_access_writable(access_flags: access);
252 umem_odp->umem.owning_mm = current->mm;
253 umem_odp->notifier.ops = ops;
254
255 umem_odp->page_shift = PAGE_SHIFT;
256#ifdef CONFIG_HUGETLB_PAGE
257 if (access & IB_ACCESS_HUGETLB)
258 umem_odp->page_shift = HPAGE_SHIFT;
259#endif
260
261 umem_odp->tgid = get_task_pid(current->group_leader, type: PIDTYPE_PID);
262 ret = ib_init_umem_odp(umem_odp, ops);
263 if (ret)
264 goto err_put_pid;
265 return umem_odp;
266
267err_put_pid:
268 put_pid(pid: umem_odp->tgid);
269 kfree(objp: umem_odp);
270 return ERR_PTR(error: ret);
271}
272EXPORT_SYMBOL(ib_umem_odp_get);
273
274static void ib_umem_odp_free(struct ib_umem_odp *umem_odp)
275{
276 struct ib_device *dev = umem_odp->umem.ibdev;
277
278 /*
279 * Ensure that no more pages are mapped in the umem.
280 *
281 * It is the driver's responsibility to ensure, before calling us,
282 * that the hardware will not attempt to access the MR any more.
283 */
284 mutex_lock(&umem_odp->umem_mutex);
285 ib_umem_odp_unmap_dma_pages(umem_odp, start_offset: ib_umem_start(umem_odp),
286 bound: ib_umem_end(umem_odp));
287 mutex_unlock(lock: &umem_odp->umem_mutex);
288 mmu_interval_notifier_remove(interval_sub: &umem_odp->notifier);
289 if (ib_uses_virt_dma(dev))
290 kvfree(addr: umem_odp->map.pfn_list);
291 else
292 hmm_dma_map_free(dev: dev->dma_device, map: &umem_odp->map);
293}
294
295void ib_umem_odp_release(struct ib_umem_odp *umem_odp)
296{
297 if (!umem_odp->is_implicit_odp)
298 ib_umem_odp_free(umem_odp);
299
300 put_pid(pid: umem_odp->tgid);
301 kfree(objp: umem_odp);
302}
303EXPORT_SYMBOL(ib_umem_odp_release);
304
305/**
306 * ib_umem_odp_map_dma_and_lock - DMA map userspace memory in an ODP MR and lock it.
307 *
308 * Maps the range passed in the argument to DMA addresses.
309 * Upon success the ODP MR will be locked to let caller complete its device
310 * page table update.
311 *
312 * Returns the number of pages mapped in success, negative error code
313 * for failure.
314 * @umem_odp: the umem to map and pin
315 * @user_virt: the address from which we need to map.
316 * @bcnt: the minimal number of bytes to pin and map. The mapping might be
317 * bigger due to alignment, and may also be smaller in case of an error
318 * pinning or mapping a page. The actual pages mapped is returned in
319 * the return value.
320 * @access_mask: bit mask of the requested access permissions for the given
321 * range.
322 * @fault: is faulting required for the given range
323 */
324int ib_umem_odp_map_dma_and_lock(struct ib_umem_odp *umem_odp, u64 user_virt,
325 u64 bcnt, u64 access_mask, bool fault)
326 __acquires(&umem_odp->umem_mutex)
327{
328 struct task_struct *owning_process = NULL;
329 struct mm_struct *owning_mm = umem_odp->umem.owning_mm;
330 int pfn_index, dma_index, ret = 0, start_idx;
331 unsigned int page_shift, hmm_order, pfn_start_idx;
332 unsigned long num_pfns, current_seq;
333 struct hmm_range range = {};
334 unsigned long timeout;
335
336 if (user_virt < ib_umem_start(umem_odp) ||
337 user_virt + bcnt > ib_umem_end(umem_odp))
338 return -EFAULT;
339
340 page_shift = umem_odp->page_shift;
341
342 /*
343 * owning_process is allowed to be NULL, this means somehow the mm is
344 * existing beyond the lifetime of the originating process.. Presumably
345 * mmget_not_zero will fail in this case.
346 */
347 owning_process = get_pid_task(pid: umem_odp->tgid, PIDTYPE_PID);
348 if (!owning_process || !mmget_not_zero(mm: owning_mm)) {
349 ret = -EINVAL;
350 goto out_put_task;
351 }
352
353 range.notifier = &umem_odp->notifier;
354 range.start = ALIGN_DOWN(user_virt, 1UL << page_shift);
355 range.end = ALIGN(user_virt + bcnt, 1UL << page_shift);
356 pfn_start_idx = (range.start - ib_umem_start(umem_odp)) >> PAGE_SHIFT;
357 num_pfns = (range.end - range.start) >> PAGE_SHIFT;
358 if (fault) {
359 range.default_flags = HMM_PFN_REQ_FAULT;
360
361 if (access_mask & HMM_PFN_WRITE)
362 range.default_flags |= HMM_PFN_REQ_WRITE;
363 }
364
365 range.hmm_pfns = &(umem_odp->map.pfn_list[pfn_start_idx]);
366 timeout = jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
367
368retry:
369 current_seq = range.notifier_seq =
370 mmu_interval_read_begin(interval_sub: &umem_odp->notifier);
371
372 mmap_read_lock(mm: owning_mm);
373 ret = hmm_range_fault(range: &range);
374 mmap_read_unlock(mm: owning_mm);
375 if (unlikely(ret)) {
376 if (ret == -EBUSY && !time_after(jiffies, timeout))
377 goto retry;
378 goto out_put_mm;
379 }
380
381 start_idx = (range.start - ib_umem_start(umem_odp)) >> page_shift;
382 dma_index = start_idx;
383
384 mutex_lock(&umem_odp->umem_mutex);
385 if (mmu_interval_read_retry(interval_sub: &umem_odp->notifier, seq: current_seq)) {
386 mutex_unlock(lock: &umem_odp->umem_mutex);
387 goto retry;
388 }
389
390 for (pfn_index = 0; pfn_index < num_pfns;
391 pfn_index += 1 << (page_shift - PAGE_SHIFT), dma_index++) {
392
393 /*
394 * Since we asked for hmm_range_fault() to populate
395 * pages it shouldn't return an error entry on success.
396 */
397 WARN_ON(fault && range.hmm_pfns[pfn_index] & HMM_PFN_ERROR);
398 WARN_ON(fault && !(range.hmm_pfns[pfn_index] & HMM_PFN_VALID));
399 if (!(range.hmm_pfns[pfn_index] & HMM_PFN_VALID))
400 continue;
401
402 if (range.hmm_pfns[pfn_index] & HMM_PFN_DMA_MAPPED)
403 continue;
404
405 hmm_order = hmm_pfn_to_map_order(hmm_pfn: range.hmm_pfns[pfn_index]);
406 /* If a hugepage was detected and ODP wasn't set for, the umem
407 * page_shift will be used, the opposite case is an error.
408 */
409 if (hmm_order + PAGE_SHIFT < page_shift) {
410 ret = -EINVAL;
411 ibdev_dbg(umem_odp->umem.ibdev,
412 "%s: un-expected hmm_order %u, page_shift %u\n",
413 __func__, hmm_order, page_shift);
414 break;
415 }
416 }
417 /* upon success lock should stay on hold for the callee */
418 if (!ret)
419 ret = dma_index - start_idx;
420 else
421 mutex_unlock(lock: &umem_odp->umem_mutex);
422
423out_put_mm:
424 mmput_async(owning_mm);
425out_put_task:
426 if (owning_process)
427 put_task_struct(t: owning_process);
428 return ret;
429}
430EXPORT_SYMBOL(ib_umem_odp_map_dma_and_lock);
431
432void ib_umem_odp_unmap_dma_pages(struct ib_umem_odp *umem_odp, u64 virt,
433 u64 bound)
434{
435 struct ib_device *dev = umem_odp->umem.ibdev;
436 u64 addr;
437
438 lockdep_assert_held(&umem_odp->umem_mutex);
439
440 virt = max_t(u64, virt, ib_umem_start(umem_odp));
441 bound = min_t(u64, bound, ib_umem_end(umem_odp));
442 for (addr = virt; addr < bound; addr += BIT(umem_odp->page_shift)) {
443 u64 offset = addr - ib_umem_start(umem_odp);
444 size_t idx = offset >> umem_odp->page_shift;
445 unsigned long pfn = umem_odp->map.pfn_list[idx];
446
447 if (!hmm_dma_unmap_pfn(dev: dev->dma_device, map: &umem_odp->map, idx))
448 goto clear;
449
450 if (pfn & HMM_PFN_WRITE) {
451 struct page *page = hmm_pfn_to_page(hmm_pfn: pfn);
452 struct page *head_page = compound_head(page);
453 /*
454 * set_page_dirty prefers being called with
455 * the page lock. However, MMU notifiers are
456 * called sometimes with and sometimes without
457 * the lock. We rely on the umem_mutex instead
458 * to prevent other mmu notifiers from
459 * continuing and allowing the page mapping to
460 * be removed.
461 */
462 set_page_dirty(head_page);
463 }
464 umem_odp->npages--;
465clear:
466 umem_odp->map.pfn_list[idx] &= ~HMM_PFN_FLAGS;
467 }
468}
469EXPORT_SYMBOL(ib_umem_odp_unmap_dma_pages);
470

source code of linux/drivers/infiniband/core/umem_odp.c