Commit | Line | Data |
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133ff0ea JG |
1 | /* |
2 | * Copyright 2013 Red Hat Inc. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
f813f219 | 14 | * Authors: Jérôme Glisse <jglisse@redhat.com> |
133ff0ea JG |
15 | */ |
16 | /* | |
17 | * Refer to include/linux/hmm.h for information about heterogeneous memory | |
18 | * management or HMM for short. | |
19 | */ | |
20 | #include <linux/mm.h> | |
21 | #include <linux/hmm.h> | |
858b54da | 22 | #include <linux/init.h> |
da4c3c73 JG |
23 | #include <linux/rmap.h> |
24 | #include <linux/swap.h> | |
133ff0ea JG |
25 | #include <linux/slab.h> |
26 | #include <linux/sched.h> | |
4ef589dc JG |
27 | #include <linux/mmzone.h> |
28 | #include <linux/pagemap.h> | |
da4c3c73 JG |
29 | #include <linux/swapops.h> |
30 | #include <linux/hugetlb.h> | |
4ef589dc | 31 | #include <linux/memremap.h> |
7b2d55d2 | 32 | #include <linux/jump_label.h> |
c0b12405 | 33 | #include <linux/mmu_notifier.h> |
4ef589dc JG |
34 | #include <linux/memory_hotplug.h> |
35 | ||
36 | #define PA_SECTION_SIZE (1UL << PA_SECTION_SHIFT) | |
133ff0ea | 37 | |
6b368cd4 | 38 | #if IS_ENABLED(CONFIG_HMM_MIRROR) |
c0b12405 JG |
39 | static const struct mmu_notifier_ops hmm_mmu_notifier_ops; |
40 | ||
704f3f2c JG |
41 | static inline struct hmm *mm_get_hmm(struct mm_struct *mm) |
42 | { | |
43 | struct hmm *hmm = READ_ONCE(mm->hmm); | |
44 | ||
45 | if (hmm && kref_get_unless_zero(&hmm->kref)) | |
46 | return hmm; | |
47 | ||
48 | return NULL; | |
49 | } | |
50 | ||
51 | /** | |
52 | * hmm_get_or_create - register HMM against an mm (HMM internal) | |
133ff0ea JG |
53 | * |
54 | * @mm: mm struct to attach to | |
704f3f2c JG |
55 | * Returns: returns an HMM object, either by referencing the existing |
56 | * (per-process) object, or by creating a new one. | |
133ff0ea | 57 | * |
704f3f2c JG |
58 | * This is not intended to be used directly by device drivers. If mm already |
59 | * has an HMM struct then it get a reference on it and returns it. Otherwise | |
60 | * it allocates an HMM struct, initializes it, associate it with the mm and | |
61 | * returns it. | |
133ff0ea | 62 | */ |
704f3f2c | 63 | static struct hmm *hmm_get_or_create(struct mm_struct *mm) |
133ff0ea | 64 | { |
704f3f2c | 65 | struct hmm *hmm = mm_get_hmm(mm); |
c0b12405 | 66 | bool cleanup = false; |
133ff0ea | 67 | |
c0b12405 JG |
68 | if (hmm) |
69 | return hmm; | |
70 | ||
71 | hmm = kmalloc(sizeof(*hmm), GFP_KERNEL); | |
72 | if (!hmm) | |
73 | return NULL; | |
a3e0d41c | 74 | init_waitqueue_head(&hmm->wq); |
c0b12405 JG |
75 | INIT_LIST_HEAD(&hmm->mirrors); |
76 | init_rwsem(&hmm->mirrors_sem); | |
c0b12405 | 77 | hmm->mmu_notifier.ops = NULL; |
da4c3c73 | 78 | INIT_LIST_HEAD(&hmm->ranges); |
a3e0d41c | 79 | mutex_init(&hmm->lock); |
704f3f2c | 80 | kref_init(&hmm->kref); |
a3e0d41c JG |
81 | hmm->notifiers = 0; |
82 | hmm->dead = false; | |
c0b12405 JG |
83 | hmm->mm = mm; |
84 | ||
c0b12405 JG |
85 | spin_lock(&mm->page_table_lock); |
86 | if (!mm->hmm) | |
87 | mm->hmm = hmm; | |
88 | else | |
89 | cleanup = true; | |
90 | spin_unlock(&mm->page_table_lock); | |
91 | ||
86a2d598 RC |
92 | if (cleanup) |
93 | goto error; | |
94 | ||
95 | /* | |
96 | * We should only get here if hold the mmap_sem in write mode ie on | |
97 | * registration of first mirror through hmm_mirror_register() | |
98 | */ | |
99 | hmm->mmu_notifier.ops = &hmm_mmu_notifier_ops; | |
100 | if (__mmu_notifier_register(&hmm->mmu_notifier, mm)) | |
101 | goto error_mm; | |
c0b12405 | 102 | |
704f3f2c | 103 | return hmm; |
86a2d598 RC |
104 | |
105 | error_mm: | |
106 | spin_lock(&mm->page_table_lock); | |
107 | if (mm->hmm == hmm) | |
108 | mm->hmm = NULL; | |
109 | spin_unlock(&mm->page_table_lock); | |
110 | error: | |
111 | kfree(hmm); | |
112 | return NULL; | |
133ff0ea JG |
113 | } |
114 | ||
704f3f2c JG |
115 | static void hmm_free(struct kref *kref) |
116 | { | |
117 | struct hmm *hmm = container_of(kref, struct hmm, kref); | |
118 | struct mm_struct *mm = hmm->mm; | |
119 | ||
120 | mmu_notifier_unregister_no_release(&hmm->mmu_notifier, mm); | |
121 | ||
122 | spin_lock(&mm->page_table_lock); | |
123 | if (mm->hmm == hmm) | |
124 | mm->hmm = NULL; | |
125 | spin_unlock(&mm->page_table_lock); | |
126 | ||
127 | kfree(hmm); | |
128 | } | |
129 | ||
130 | static inline void hmm_put(struct hmm *hmm) | |
131 | { | |
132 | kref_put(&hmm->kref, hmm_free); | |
133 | } | |
134 | ||
133ff0ea JG |
135 | void hmm_mm_destroy(struct mm_struct *mm) |
136 | { | |
704f3f2c JG |
137 | struct hmm *hmm; |
138 | ||
139 | spin_lock(&mm->page_table_lock); | |
140 | hmm = mm_get_hmm(mm); | |
141 | mm->hmm = NULL; | |
142 | if (hmm) { | |
143 | hmm->mm = NULL; | |
a3e0d41c | 144 | hmm->dead = true; |
704f3f2c JG |
145 | spin_unlock(&mm->page_table_lock); |
146 | hmm_put(hmm); | |
147 | return; | |
148 | } | |
149 | ||
150 | spin_unlock(&mm->page_table_lock); | |
133ff0ea | 151 | } |
c0b12405 | 152 | |
a3e0d41c | 153 | static void hmm_release(struct mmu_notifier *mn, struct mm_struct *mm) |
c0b12405 | 154 | { |
a3e0d41c | 155 | struct hmm *hmm = mm_get_hmm(mm); |
c0b12405 | 156 | struct hmm_mirror *mirror; |
da4c3c73 JG |
157 | struct hmm_range *range; |
158 | ||
a3e0d41c JG |
159 | /* Report this HMM as dying. */ |
160 | hmm->dead = true; | |
da4c3c73 | 161 | |
a3e0d41c JG |
162 | /* Wake-up everyone waiting on any range. */ |
163 | mutex_lock(&hmm->lock); | |
164 | list_for_each_entry(range, &hmm->ranges, list) { | |
da4c3c73 | 165 | range->valid = false; |
da4c3c73 | 166 | } |
a3e0d41c JG |
167 | wake_up_all(&hmm->wq); |
168 | mutex_unlock(&hmm->lock); | |
e1401513 RC |
169 | |
170 | down_write(&hmm->mirrors_sem); | |
171 | mirror = list_first_entry_or_null(&hmm->mirrors, struct hmm_mirror, | |
172 | list); | |
173 | while (mirror) { | |
174 | list_del_init(&mirror->list); | |
175 | if (mirror->ops->release) { | |
176 | /* | |
177 | * Drop mirrors_sem so callback can wait on any pending | |
178 | * work that might itself trigger mmu_notifier callback | |
179 | * and thus would deadlock with us. | |
180 | */ | |
181 | up_write(&hmm->mirrors_sem); | |
182 | mirror->ops->release(mirror); | |
183 | down_write(&hmm->mirrors_sem); | |
184 | } | |
185 | mirror = list_first_entry_or_null(&hmm->mirrors, | |
186 | struct hmm_mirror, list); | |
187 | } | |
188 | up_write(&hmm->mirrors_sem); | |
704f3f2c JG |
189 | |
190 | hmm_put(hmm); | |
e1401513 RC |
191 | } |
192 | ||
93065ac7 | 193 | static int hmm_invalidate_range_start(struct mmu_notifier *mn, |
a3e0d41c | 194 | const struct mmu_notifier_range *nrange) |
c0b12405 | 195 | { |
a3e0d41c JG |
196 | struct hmm *hmm = mm_get_hmm(nrange->mm); |
197 | struct hmm_mirror *mirror; | |
ec131b2d | 198 | struct hmm_update update; |
a3e0d41c JG |
199 | struct hmm_range *range; |
200 | int ret = 0; | |
c0b12405 JG |
201 | |
202 | VM_BUG_ON(!hmm); | |
203 | ||
a3e0d41c JG |
204 | update.start = nrange->start; |
205 | update.end = nrange->end; | |
ec131b2d | 206 | update.event = HMM_UPDATE_INVALIDATE; |
a3e0d41c JG |
207 | update.blockable = nrange->blockable; |
208 | ||
209 | if (nrange->blockable) | |
210 | mutex_lock(&hmm->lock); | |
211 | else if (!mutex_trylock(&hmm->lock)) { | |
212 | ret = -EAGAIN; | |
213 | goto out; | |
214 | } | |
215 | hmm->notifiers++; | |
216 | list_for_each_entry(range, &hmm->ranges, list) { | |
217 | if (update.end < range->start || update.start >= range->end) | |
218 | continue; | |
219 | ||
220 | range->valid = false; | |
221 | } | |
222 | mutex_unlock(&hmm->lock); | |
223 | ||
224 | if (nrange->blockable) | |
225 | down_read(&hmm->mirrors_sem); | |
226 | else if (!down_read_trylock(&hmm->mirrors_sem)) { | |
227 | ret = -EAGAIN; | |
228 | goto out; | |
229 | } | |
230 | list_for_each_entry(mirror, &hmm->mirrors, list) { | |
231 | int ret; | |
232 | ||
233 | ret = mirror->ops->sync_cpu_device_pagetables(mirror, &update); | |
234 | if (!update.blockable && ret == -EAGAIN) { | |
235 | up_read(&hmm->mirrors_sem); | |
236 | ret = -EAGAIN; | |
237 | goto out; | |
238 | } | |
239 | } | |
240 | up_read(&hmm->mirrors_sem); | |
241 | ||
242 | out: | |
704f3f2c JG |
243 | hmm_put(hmm); |
244 | return ret; | |
c0b12405 JG |
245 | } |
246 | ||
247 | static void hmm_invalidate_range_end(struct mmu_notifier *mn, | |
a3e0d41c | 248 | const struct mmu_notifier_range *nrange) |
c0b12405 | 249 | { |
a3e0d41c | 250 | struct hmm *hmm = mm_get_hmm(nrange->mm); |
c0b12405 JG |
251 | |
252 | VM_BUG_ON(!hmm); | |
253 | ||
a3e0d41c JG |
254 | mutex_lock(&hmm->lock); |
255 | hmm->notifiers--; | |
256 | if (!hmm->notifiers) { | |
257 | struct hmm_range *range; | |
258 | ||
259 | list_for_each_entry(range, &hmm->ranges, list) { | |
260 | if (range->valid) | |
261 | continue; | |
262 | range->valid = true; | |
263 | } | |
264 | wake_up_all(&hmm->wq); | |
265 | } | |
266 | mutex_unlock(&hmm->lock); | |
267 | ||
704f3f2c | 268 | hmm_put(hmm); |
c0b12405 JG |
269 | } |
270 | ||
271 | static const struct mmu_notifier_ops hmm_mmu_notifier_ops = { | |
e1401513 | 272 | .release = hmm_release, |
c0b12405 JG |
273 | .invalidate_range_start = hmm_invalidate_range_start, |
274 | .invalidate_range_end = hmm_invalidate_range_end, | |
275 | }; | |
276 | ||
277 | /* | |
278 | * hmm_mirror_register() - register a mirror against an mm | |
279 | * | |
280 | * @mirror: new mirror struct to register | |
281 | * @mm: mm to register against | |
282 | * | |
283 | * To start mirroring a process address space, the device driver must register | |
284 | * an HMM mirror struct. | |
285 | * | |
286 | * THE mm->mmap_sem MUST BE HELD IN WRITE MODE ! | |
287 | */ | |
288 | int hmm_mirror_register(struct hmm_mirror *mirror, struct mm_struct *mm) | |
289 | { | |
290 | /* Sanity check */ | |
291 | if (!mm || !mirror || !mirror->ops) | |
292 | return -EINVAL; | |
293 | ||
704f3f2c | 294 | mirror->hmm = hmm_get_or_create(mm); |
c0b12405 JG |
295 | if (!mirror->hmm) |
296 | return -ENOMEM; | |
297 | ||
298 | down_write(&mirror->hmm->mirrors_sem); | |
704f3f2c JG |
299 | list_add(&mirror->list, &mirror->hmm->mirrors); |
300 | up_write(&mirror->hmm->mirrors_sem); | |
c0b12405 JG |
301 | |
302 | return 0; | |
303 | } | |
304 | EXPORT_SYMBOL(hmm_mirror_register); | |
305 | ||
306 | /* | |
307 | * hmm_mirror_unregister() - unregister a mirror | |
308 | * | |
309 | * @mirror: new mirror struct to register | |
310 | * | |
311 | * Stop mirroring a process address space, and cleanup. | |
312 | */ | |
313 | void hmm_mirror_unregister(struct hmm_mirror *mirror) | |
314 | { | |
704f3f2c | 315 | struct hmm *hmm = READ_ONCE(mirror->hmm); |
c01cbba2 | 316 | |
704f3f2c | 317 | if (hmm == NULL) |
c01cbba2 | 318 | return; |
c0b12405 JG |
319 | |
320 | down_write(&hmm->mirrors_sem); | |
e1401513 | 321 | list_del_init(&mirror->list); |
704f3f2c | 322 | /* To protect us against double unregister ... */ |
c01cbba2 | 323 | mirror->hmm = NULL; |
c0b12405 | 324 | up_write(&hmm->mirrors_sem); |
c01cbba2 | 325 | |
704f3f2c | 326 | hmm_put(hmm); |
c0b12405 JG |
327 | } |
328 | EXPORT_SYMBOL(hmm_mirror_unregister); | |
da4c3c73 | 329 | |
74eee180 JG |
330 | struct hmm_vma_walk { |
331 | struct hmm_range *range; | |
332 | unsigned long last; | |
333 | bool fault; | |
334 | bool block; | |
74eee180 JG |
335 | }; |
336 | ||
2aee09d8 JG |
337 | static int hmm_vma_do_fault(struct mm_walk *walk, unsigned long addr, |
338 | bool write_fault, uint64_t *pfn) | |
74eee180 JG |
339 | { |
340 | unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_REMOTE; | |
341 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
f88a1e90 | 342 | struct hmm_range *range = hmm_vma_walk->range; |
74eee180 | 343 | struct vm_area_struct *vma = walk->vma; |
50a7ca3c | 344 | vm_fault_t ret; |
74eee180 JG |
345 | |
346 | flags |= hmm_vma_walk->block ? 0 : FAULT_FLAG_ALLOW_RETRY; | |
2aee09d8 | 347 | flags |= write_fault ? FAULT_FLAG_WRITE : 0; |
50a7ca3c SJ |
348 | ret = handle_mm_fault(vma, addr, flags); |
349 | if (ret & VM_FAULT_RETRY) | |
73231612 | 350 | return -EAGAIN; |
50a7ca3c | 351 | if (ret & VM_FAULT_ERROR) { |
f88a1e90 | 352 | *pfn = range->values[HMM_PFN_ERROR]; |
74eee180 JG |
353 | return -EFAULT; |
354 | } | |
355 | ||
73231612 | 356 | return -EBUSY; |
74eee180 JG |
357 | } |
358 | ||
da4c3c73 JG |
359 | static int hmm_pfns_bad(unsigned long addr, |
360 | unsigned long end, | |
361 | struct mm_walk *walk) | |
362 | { | |
c719547f JG |
363 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
364 | struct hmm_range *range = hmm_vma_walk->range; | |
ff05c0c6 | 365 | uint64_t *pfns = range->pfns; |
da4c3c73 JG |
366 | unsigned long i; |
367 | ||
368 | i = (addr - range->start) >> PAGE_SHIFT; | |
369 | for (; addr < end; addr += PAGE_SIZE, i++) | |
f88a1e90 | 370 | pfns[i] = range->values[HMM_PFN_ERROR]; |
da4c3c73 JG |
371 | |
372 | return 0; | |
373 | } | |
374 | ||
5504ed29 JG |
375 | /* |
376 | * hmm_vma_walk_hole() - handle a range lacking valid pmd or pte(s) | |
377 | * @start: range virtual start address (inclusive) | |
378 | * @end: range virtual end address (exclusive) | |
2aee09d8 JG |
379 | * @fault: should we fault or not ? |
380 | * @write_fault: write fault ? | |
5504ed29 | 381 | * @walk: mm_walk structure |
73231612 | 382 | * Returns: 0 on success, -EBUSY after page fault, or page fault error |
5504ed29 JG |
383 | * |
384 | * This function will be called whenever pmd_none() or pte_none() returns true, | |
385 | * or whenever there is no page directory covering the virtual address range. | |
386 | */ | |
2aee09d8 JG |
387 | static int hmm_vma_walk_hole_(unsigned long addr, unsigned long end, |
388 | bool fault, bool write_fault, | |
389 | struct mm_walk *walk) | |
da4c3c73 | 390 | { |
74eee180 JG |
391 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
392 | struct hmm_range *range = hmm_vma_walk->range; | |
ff05c0c6 | 393 | uint64_t *pfns = range->pfns; |
da4c3c73 JG |
394 | unsigned long i; |
395 | ||
74eee180 | 396 | hmm_vma_walk->last = addr; |
da4c3c73 | 397 | i = (addr - range->start) >> PAGE_SHIFT; |
74eee180 | 398 | for (; addr < end; addr += PAGE_SIZE, i++) { |
f88a1e90 | 399 | pfns[i] = range->values[HMM_PFN_NONE]; |
2aee09d8 | 400 | if (fault || write_fault) { |
74eee180 | 401 | int ret; |
da4c3c73 | 402 | |
2aee09d8 JG |
403 | ret = hmm_vma_do_fault(walk, addr, write_fault, |
404 | &pfns[i]); | |
73231612 | 405 | if (ret != -EBUSY) |
74eee180 JG |
406 | return ret; |
407 | } | |
408 | } | |
409 | ||
73231612 | 410 | return (fault || write_fault) ? -EBUSY : 0; |
2aee09d8 JG |
411 | } |
412 | ||
413 | static inline void hmm_pte_need_fault(const struct hmm_vma_walk *hmm_vma_walk, | |
414 | uint64_t pfns, uint64_t cpu_flags, | |
415 | bool *fault, bool *write_fault) | |
416 | { | |
f88a1e90 JG |
417 | struct hmm_range *range = hmm_vma_walk->range; |
418 | ||
2aee09d8 JG |
419 | if (!hmm_vma_walk->fault) |
420 | return; | |
421 | ||
023a019a JG |
422 | /* |
423 | * So we not only consider the individual per page request we also | |
424 | * consider the default flags requested for the range. The API can | |
425 | * be use in 2 fashions. The first one where the HMM user coalesce | |
426 | * multiple page fault into one request and set flags per pfns for | |
427 | * of those faults. The second one where the HMM user want to pre- | |
428 | * fault a range with specific flags. For the latter one it is a | |
429 | * waste to have the user pre-fill the pfn arrays with a default | |
430 | * flags value. | |
431 | */ | |
432 | pfns = (pfns & range->pfn_flags_mask) | range->default_flags; | |
433 | ||
2aee09d8 | 434 | /* We aren't ask to do anything ... */ |
f88a1e90 | 435 | if (!(pfns & range->flags[HMM_PFN_VALID])) |
2aee09d8 | 436 | return; |
f88a1e90 JG |
437 | /* If this is device memory than only fault if explicitly requested */ |
438 | if ((cpu_flags & range->flags[HMM_PFN_DEVICE_PRIVATE])) { | |
439 | /* Do we fault on device memory ? */ | |
440 | if (pfns & range->flags[HMM_PFN_DEVICE_PRIVATE]) { | |
441 | *write_fault = pfns & range->flags[HMM_PFN_WRITE]; | |
442 | *fault = true; | |
443 | } | |
2aee09d8 JG |
444 | return; |
445 | } | |
f88a1e90 JG |
446 | |
447 | /* If CPU page table is not valid then we need to fault */ | |
448 | *fault = !(cpu_flags & range->flags[HMM_PFN_VALID]); | |
449 | /* Need to write fault ? */ | |
450 | if ((pfns & range->flags[HMM_PFN_WRITE]) && | |
451 | !(cpu_flags & range->flags[HMM_PFN_WRITE])) { | |
452 | *write_fault = true; | |
2aee09d8 JG |
453 | *fault = true; |
454 | } | |
455 | } | |
456 | ||
457 | static void hmm_range_need_fault(const struct hmm_vma_walk *hmm_vma_walk, | |
458 | const uint64_t *pfns, unsigned long npages, | |
459 | uint64_t cpu_flags, bool *fault, | |
460 | bool *write_fault) | |
461 | { | |
462 | unsigned long i; | |
463 | ||
464 | if (!hmm_vma_walk->fault) { | |
465 | *fault = *write_fault = false; | |
466 | return; | |
467 | } | |
468 | ||
a3e0d41c | 469 | *fault = *write_fault = false; |
2aee09d8 JG |
470 | for (i = 0; i < npages; ++i) { |
471 | hmm_pte_need_fault(hmm_vma_walk, pfns[i], cpu_flags, | |
472 | fault, write_fault); | |
a3e0d41c | 473 | if ((*write_fault)) |
2aee09d8 JG |
474 | return; |
475 | } | |
476 | } | |
477 | ||
478 | static int hmm_vma_walk_hole(unsigned long addr, unsigned long end, | |
479 | struct mm_walk *walk) | |
480 | { | |
481 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
482 | struct hmm_range *range = hmm_vma_walk->range; | |
483 | bool fault, write_fault; | |
484 | unsigned long i, npages; | |
485 | uint64_t *pfns; | |
486 | ||
487 | i = (addr - range->start) >> PAGE_SHIFT; | |
488 | npages = (end - addr) >> PAGE_SHIFT; | |
489 | pfns = &range->pfns[i]; | |
490 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, | |
491 | 0, &fault, &write_fault); | |
492 | return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk); | |
493 | } | |
494 | ||
f88a1e90 | 495 | static inline uint64_t pmd_to_hmm_pfn_flags(struct hmm_range *range, pmd_t pmd) |
2aee09d8 JG |
496 | { |
497 | if (pmd_protnone(pmd)) | |
498 | return 0; | |
f88a1e90 JG |
499 | return pmd_write(pmd) ? range->flags[HMM_PFN_VALID] | |
500 | range->flags[HMM_PFN_WRITE] : | |
501 | range->flags[HMM_PFN_VALID]; | |
da4c3c73 JG |
502 | } |
503 | ||
53f5c3f4 JG |
504 | static int hmm_vma_handle_pmd(struct mm_walk *walk, |
505 | unsigned long addr, | |
506 | unsigned long end, | |
507 | uint64_t *pfns, | |
508 | pmd_t pmd) | |
509 | { | |
510 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
f88a1e90 | 511 | struct hmm_range *range = hmm_vma_walk->range; |
2aee09d8 | 512 | unsigned long pfn, npages, i; |
2aee09d8 | 513 | bool fault, write_fault; |
f88a1e90 | 514 | uint64_t cpu_flags; |
53f5c3f4 | 515 | |
2aee09d8 | 516 | npages = (end - addr) >> PAGE_SHIFT; |
f88a1e90 | 517 | cpu_flags = pmd_to_hmm_pfn_flags(range, pmd); |
2aee09d8 JG |
518 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, cpu_flags, |
519 | &fault, &write_fault); | |
53f5c3f4 | 520 | |
2aee09d8 JG |
521 | if (pmd_protnone(pmd) || fault || write_fault) |
522 | return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk); | |
53f5c3f4 JG |
523 | |
524 | pfn = pmd_pfn(pmd) + pte_index(addr); | |
53f5c3f4 | 525 | for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++) |
f88a1e90 | 526 | pfns[i] = hmm_pfn_from_pfn(range, pfn) | cpu_flags; |
53f5c3f4 JG |
527 | hmm_vma_walk->last = end; |
528 | return 0; | |
529 | } | |
530 | ||
f88a1e90 | 531 | static inline uint64_t pte_to_hmm_pfn_flags(struct hmm_range *range, pte_t pte) |
2aee09d8 JG |
532 | { |
533 | if (pte_none(pte) || !pte_present(pte)) | |
534 | return 0; | |
f88a1e90 JG |
535 | return pte_write(pte) ? range->flags[HMM_PFN_VALID] | |
536 | range->flags[HMM_PFN_WRITE] : | |
537 | range->flags[HMM_PFN_VALID]; | |
2aee09d8 JG |
538 | } |
539 | ||
53f5c3f4 JG |
540 | static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr, |
541 | unsigned long end, pmd_t *pmdp, pte_t *ptep, | |
542 | uint64_t *pfn) | |
543 | { | |
544 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
f88a1e90 | 545 | struct hmm_range *range = hmm_vma_walk->range; |
53f5c3f4 | 546 | struct vm_area_struct *vma = walk->vma; |
2aee09d8 JG |
547 | bool fault, write_fault; |
548 | uint64_t cpu_flags; | |
53f5c3f4 | 549 | pte_t pte = *ptep; |
f88a1e90 | 550 | uint64_t orig_pfn = *pfn; |
53f5c3f4 | 551 | |
f88a1e90 | 552 | *pfn = range->values[HMM_PFN_NONE]; |
73231612 | 553 | fault = write_fault = false; |
53f5c3f4 JG |
554 | |
555 | if (pte_none(pte)) { | |
73231612 JG |
556 | hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0, |
557 | &fault, &write_fault); | |
2aee09d8 | 558 | if (fault || write_fault) |
53f5c3f4 JG |
559 | goto fault; |
560 | return 0; | |
561 | } | |
562 | ||
563 | if (!pte_present(pte)) { | |
564 | swp_entry_t entry = pte_to_swp_entry(pte); | |
565 | ||
566 | if (!non_swap_entry(entry)) { | |
2aee09d8 | 567 | if (fault || write_fault) |
53f5c3f4 JG |
568 | goto fault; |
569 | return 0; | |
570 | } | |
571 | ||
572 | /* | |
573 | * This is a special swap entry, ignore migration, use | |
574 | * device and report anything else as error. | |
575 | */ | |
576 | if (is_device_private_entry(entry)) { | |
f88a1e90 JG |
577 | cpu_flags = range->flags[HMM_PFN_VALID] | |
578 | range->flags[HMM_PFN_DEVICE_PRIVATE]; | |
2aee09d8 | 579 | cpu_flags |= is_write_device_private_entry(entry) ? |
f88a1e90 JG |
580 | range->flags[HMM_PFN_WRITE] : 0; |
581 | hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags, | |
582 | &fault, &write_fault); | |
583 | if (fault || write_fault) | |
584 | goto fault; | |
585 | *pfn = hmm_pfn_from_pfn(range, swp_offset(entry)); | |
586 | *pfn |= cpu_flags; | |
53f5c3f4 JG |
587 | return 0; |
588 | } | |
589 | ||
590 | if (is_migration_entry(entry)) { | |
2aee09d8 | 591 | if (fault || write_fault) { |
53f5c3f4 JG |
592 | pte_unmap(ptep); |
593 | hmm_vma_walk->last = addr; | |
594 | migration_entry_wait(vma->vm_mm, | |
2aee09d8 | 595 | pmdp, addr); |
73231612 | 596 | return -EBUSY; |
53f5c3f4 JG |
597 | } |
598 | return 0; | |
599 | } | |
600 | ||
601 | /* Report error for everything else */ | |
f88a1e90 | 602 | *pfn = range->values[HMM_PFN_ERROR]; |
53f5c3f4 | 603 | return -EFAULT; |
73231612 JG |
604 | } else { |
605 | cpu_flags = pte_to_hmm_pfn_flags(range, pte); | |
606 | hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags, | |
607 | &fault, &write_fault); | |
53f5c3f4 JG |
608 | } |
609 | ||
2aee09d8 | 610 | if (fault || write_fault) |
53f5c3f4 JG |
611 | goto fault; |
612 | ||
f88a1e90 | 613 | *pfn = hmm_pfn_from_pfn(range, pte_pfn(pte)) | cpu_flags; |
53f5c3f4 JG |
614 | return 0; |
615 | ||
616 | fault: | |
617 | pte_unmap(ptep); | |
618 | /* Fault any virtual address we were asked to fault */ | |
2aee09d8 | 619 | return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk); |
53f5c3f4 JG |
620 | } |
621 | ||
da4c3c73 JG |
622 | static int hmm_vma_walk_pmd(pmd_t *pmdp, |
623 | unsigned long start, | |
624 | unsigned long end, | |
625 | struct mm_walk *walk) | |
626 | { | |
74eee180 JG |
627 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
628 | struct hmm_range *range = hmm_vma_walk->range; | |
d08faca0 | 629 | struct vm_area_struct *vma = walk->vma; |
ff05c0c6 | 630 | uint64_t *pfns = range->pfns; |
da4c3c73 | 631 | unsigned long addr = start, i; |
da4c3c73 | 632 | pte_t *ptep; |
d08faca0 | 633 | pmd_t pmd; |
da4c3c73 | 634 | |
da4c3c73 JG |
635 | |
636 | again: | |
d08faca0 JG |
637 | pmd = READ_ONCE(*pmdp); |
638 | if (pmd_none(pmd)) | |
da4c3c73 JG |
639 | return hmm_vma_walk_hole(start, end, walk); |
640 | ||
d08faca0 | 641 | if (pmd_huge(pmd) && (range->vma->vm_flags & VM_HUGETLB)) |
da4c3c73 JG |
642 | return hmm_pfns_bad(start, end, walk); |
643 | ||
d08faca0 JG |
644 | if (thp_migration_supported() && is_pmd_migration_entry(pmd)) { |
645 | bool fault, write_fault; | |
646 | unsigned long npages; | |
647 | uint64_t *pfns; | |
648 | ||
649 | i = (addr - range->start) >> PAGE_SHIFT; | |
650 | npages = (end - addr) >> PAGE_SHIFT; | |
651 | pfns = &range->pfns[i]; | |
652 | ||
653 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, | |
654 | 0, &fault, &write_fault); | |
655 | if (fault || write_fault) { | |
656 | hmm_vma_walk->last = addr; | |
657 | pmd_migration_entry_wait(vma->vm_mm, pmdp); | |
73231612 | 658 | return -EBUSY; |
d08faca0 JG |
659 | } |
660 | return 0; | |
661 | } else if (!pmd_present(pmd)) | |
662 | return hmm_pfns_bad(start, end, walk); | |
da4c3c73 | 663 | |
d08faca0 | 664 | if (pmd_devmap(pmd) || pmd_trans_huge(pmd)) { |
da4c3c73 JG |
665 | /* |
666 | * No need to take pmd_lock here, even if some other threads | |
667 | * is splitting the huge pmd we will get that event through | |
668 | * mmu_notifier callback. | |
669 | * | |
670 | * So just read pmd value and check again its a transparent | |
671 | * huge or device mapping one and compute corresponding pfn | |
672 | * values. | |
673 | */ | |
674 | pmd = pmd_read_atomic(pmdp); | |
675 | barrier(); | |
676 | if (!pmd_devmap(pmd) && !pmd_trans_huge(pmd)) | |
677 | goto again; | |
74eee180 | 678 | |
d08faca0 | 679 | i = (addr - range->start) >> PAGE_SHIFT; |
53f5c3f4 | 680 | return hmm_vma_handle_pmd(walk, addr, end, &pfns[i], pmd); |
da4c3c73 JG |
681 | } |
682 | ||
d08faca0 JG |
683 | /* |
684 | * We have handled all the valid case above ie either none, migration, | |
685 | * huge or transparent huge. At this point either it is a valid pmd | |
686 | * entry pointing to pte directory or it is a bad pmd that will not | |
687 | * recover. | |
688 | */ | |
689 | if (pmd_bad(pmd)) | |
da4c3c73 JG |
690 | return hmm_pfns_bad(start, end, walk); |
691 | ||
692 | ptep = pte_offset_map(pmdp, addr); | |
d08faca0 | 693 | i = (addr - range->start) >> PAGE_SHIFT; |
da4c3c73 | 694 | for (; addr < end; addr += PAGE_SIZE, ptep++, i++) { |
53f5c3f4 | 695 | int r; |
74eee180 | 696 | |
53f5c3f4 JG |
697 | r = hmm_vma_handle_pte(walk, addr, end, pmdp, ptep, &pfns[i]); |
698 | if (r) { | |
699 | /* hmm_vma_handle_pte() did unmap pte directory */ | |
700 | hmm_vma_walk->last = addr; | |
701 | return r; | |
74eee180 | 702 | } |
da4c3c73 JG |
703 | } |
704 | pte_unmap(ptep - 1); | |
705 | ||
53f5c3f4 | 706 | hmm_vma_walk->last = addr; |
da4c3c73 JG |
707 | return 0; |
708 | } | |
709 | ||
f88a1e90 JG |
710 | static void hmm_pfns_clear(struct hmm_range *range, |
711 | uint64_t *pfns, | |
33cd47dc JG |
712 | unsigned long addr, |
713 | unsigned long end) | |
714 | { | |
715 | for (; addr < end; addr += PAGE_SIZE, pfns++) | |
f88a1e90 | 716 | *pfns = range->values[HMM_PFN_NONE]; |
33cd47dc JG |
717 | } |
718 | ||
855ce7d2 JG |
719 | static void hmm_pfns_special(struct hmm_range *range) |
720 | { | |
721 | unsigned long addr = range->start, i = 0; | |
722 | ||
723 | for (; addr < range->end; addr += PAGE_SIZE, i++) | |
f88a1e90 | 724 | range->pfns[i] = range->values[HMM_PFN_SPECIAL]; |
855ce7d2 JG |
725 | } |
726 | ||
da4c3c73 | 727 | /* |
a3e0d41c | 728 | * hmm_range_register() - start tracking change to CPU page table over a range |
25f23a0c | 729 | * @range: range |
a3e0d41c JG |
730 | * @mm: the mm struct for the range of virtual address |
731 | * @start: start virtual address (inclusive) | |
732 | * @end: end virtual address (exclusive) | |
733 | * Returns 0 on success, -EFAULT if the address space is no longer valid | |
25f23a0c | 734 | * |
a3e0d41c | 735 | * Track updates to the CPU page table see include/linux/hmm.h |
da4c3c73 | 736 | */ |
a3e0d41c JG |
737 | int hmm_range_register(struct hmm_range *range, |
738 | struct mm_struct *mm, | |
739 | unsigned long start, | |
740 | unsigned long end) | |
da4c3c73 | 741 | { |
a3e0d41c JG |
742 | range->start = start & PAGE_MASK; |
743 | range->end = end & PAGE_MASK; | |
744 | range->valid = false; | |
704f3f2c JG |
745 | range->hmm = NULL; |
746 | ||
a3e0d41c | 747 | if (range->start >= range->end) |
da4c3c73 JG |
748 | return -EINVAL; |
749 | ||
a3e0d41c JG |
750 | range->start = start; |
751 | range->end = end; | |
752 | ||
753 | range->hmm = hmm_get_or_create(mm); | |
754 | if (!range->hmm) | |
755 | return -EFAULT; | |
704f3f2c JG |
756 | |
757 | /* Check if hmm_mm_destroy() was call. */ | |
a3e0d41c JG |
758 | if (range->hmm->mm == NULL || range->hmm->dead) { |
759 | hmm_put(range->hmm); | |
760 | return -EFAULT; | |
704f3f2c | 761 | } |
da4c3c73 | 762 | |
a3e0d41c JG |
763 | /* Initialize range to track CPU page table update */ |
764 | mutex_lock(&range->hmm->lock); | |
855ce7d2 | 765 | |
a3e0d41c | 766 | list_add_rcu(&range->list, &range->hmm->ranges); |
86586a41 | 767 | |
704f3f2c | 768 | /* |
a3e0d41c JG |
769 | * If there are any concurrent notifiers we have to wait for them for |
770 | * the range to be valid (see hmm_range_wait_until_valid()). | |
704f3f2c | 771 | */ |
a3e0d41c JG |
772 | if (!range->hmm->notifiers) |
773 | range->valid = true; | |
774 | mutex_unlock(&range->hmm->lock); | |
775 | ||
776 | return 0; | |
da4c3c73 | 777 | } |
a3e0d41c | 778 | EXPORT_SYMBOL(hmm_range_register); |
da4c3c73 JG |
779 | |
780 | /* | |
a3e0d41c JG |
781 | * hmm_range_unregister() - stop tracking change to CPU page table over a range |
782 | * @range: range | |
da4c3c73 JG |
783 | * |
784 | * Range struct is used to track updates to the CPU page table after a call to | |
a3e0d41c | 785 | * hmm_range_register(). See include/linux/hmm.h for how to use it. |
da4c3c73 | 786 | */ |
a3e0d41c | 787 | void hmm_range_unregister(struct hmm_range *range) |
da4c3c73 | 788 | { |
704f3f2c | 789 | /* Sanity check this really should not happen. */ |
a3e0d41c JG |
790 | if (range->hmm == NULL || range->end <= range->start) |
791 | return; | |
da4c3c73 | 792 | |
a3e0d41c | 793 | mutex_lock(&range->hmm->lock); |
da4c3c73 | 794 | list_del_rcu(&range->list); |
a3e0d41c | 795 | mutex_unlock(&range->hmm->lock); |
da4c3c73 | 796 | |
a3e0d41c JG |
797 | /* Drop reference taken by hmm_range_register() */ |
798 | range->valid = false; | |
704f3f2c JG |
799 | hmm_put(range->hmm); |
800 | range->hmm = NULL; | |
da4c3c73 | 801 | } |
a3e0d41c JG |
802 | EXPORT_SYMBOL(hmm_range_unregister); |
803 | ||
804 | /* | |
805 | * hmm_range_snapshot() - snapshot CPU page table for a range | |
806 | * @range: range | |
807 | * Returns: -EINVAL if invalid argument, -ENOMEM out of memory, -EPERM invalid | |
808 | * permission (for instance asking for write and range is read only), | |
809 | * -EAGAIN if you need to retry, -EFAULT invalid (ie either no valid | |
810 | * vma or it is illegal to access that range), number of valid pages | |
811 | * in range->pfns[] (from range start address). | |
812 | * | |
813 | * This snapshots the CPU page table for a range of virtual addresses. Snapshot | |
814 | * validity is tracked by range struct. See in include/linux/hmm.h for example | |
815 | * on how to use. | |
816 | */ | |
817 | long hmm_range_snapshot(struct hmm_range *range) | |
818 | { | |
819 | unsigned long start = range->start, end; | |
820 | struct hmm_vma_walk hmm_vma_walk; | |
821 | struct hmm *hmm = range->hmm; | |
822 | struct vm_area_struct *vma; | |
823 | struct mm_walk mm_walk; | |
824 | ||
825 | /* Check if hmm_mm_destroy() was call. */ | |
826 | if (hmm->mm == NULL || hmm->dead) | |
827 | return -EFAULT; | |
828 | ||
829 | do { | |
830 | /* If range is no longer valid force retry. */ | |
831 | if (!range->valid) | |
832 | return -EAGAIN; | |
833 | ||
834 | vma = find_vma(hmm->mm, start); | |
835 | if (vma == NULL || (vma->vm_flags & VM_SPECIAL)) | |
836 | return -EFAULT; | |
837 | ||
838 | /* FIXME support hugetlb fs/dax */ | |
839 | if (is_vm_hugetlb_page(vma) || vma_is_dax(vma)) { | |
840 | hmm_pfns_special(range); | |
841 | return -EINVAL; | |
842 | } | |
843 | ||
844 | if (!(vma->vm_flags & VM_READ)) { | |
845 | /* | |
846 | * If vma do not allow read access, then assume that it | |
847 | * does not allow write access, either. HMM does not | |
848 | * support architecture that allow write without read. | |
849 | */ | |
850 | hmm_pfns_clear(range, range->pfns, | |
851 | range->start, range->end); | |
852 | return -EPERM; | |
853 | } | |
854 | ||
855 | range->vma = vma; | |
856 | hmm_vma_walk.last = start; | |
857 | hmm_vma_walk.fault = false; | |
858 | hmm_vma_walk.range = range; | |
859 | mm_walk.private = &hmm_vma_walk; | |
860 | end = min(range->end, vma->vm_end); | |
861 | ||
862 | mm_walk.vma = vma; | |
863 | mm_walk.mm = vma->vm_mm; | |
864 | mm_walk.pte_entry = NULL; | |
865 | mm_walk.test_walk = NULL; | |
866 | mm_walk.hugetlb_entry = NULL; | |
867 | mm_walk.pmd_entry = hmm_vma_walk_pmd; | |
868 | mm_walk.pte_hole = hmm_vma_walk_hole; | |
869 | ||
870 | walk_page_range(start, end, &mm_walk); | |
871 | start = end; | |
872 | } while (start < range->end); | |
873 | ||
874 | return (hmm_vma_walk.last - range->start) >> PAGE_SHIFT; | |
875 | } | |
876 | EXPORT_SYMBOL(hmm_range_snapshot); | |
74eee180 JG |
877 | |
878 | /* | |
73231612 | 879 | * hmm_range_fault() - try to fault some address in a virtual address range |
08232a45 | 880 | * @range: range being faulted |
74eee180 | 881 | * @block: allow blocking on fault (if true it sleeps and do not drop mmap_sem) |
73231612 JG |
882 | * Returns: number of valid pages in range->pfns[] (from range start |
883 | * address). This may be zero. If the return value is negative, | |
884 | * then one of the following values may be returned: | |
885 | * | |
886 | * -EINVAL invalid arguments or mm or virtual address are in an | |
887 | * invalid vma (ie either hugetlbfs or device file vma). | |
888 | * -ENOMEM: Out of memory. | |
889 | * -EPERM: Invalid permission (for instance asking for write and | |
890 | * range is read only). | |
891 | * -EAGAIN: If you need to retry and mmap_sem was drop. This can only | |
892 | * happens if block argument is false. | |
893 | * -EBUSY: If the the range is being invalidated and you should wait | |
894 | * for invalidation to finish. | |
895 | * -EFAULT: Invalid (ie either no valid vma or it is illegal to access | |
896 | * that range), number of valid pages in range->pfns[] (from | |
897 | * range start address). | |
74eee180 JG |
898 | * |
899 | * This is similar to a regular CPU page fault except that it will not trigger | |
73231612 JG |
900 | * any memory migration if the memory being faulted is not accessible by CPUs |
901 | * and caller does not ask for migration. | |
74eee180 | 902 | * |
ff05c0c6 JG |
903 | * On error, for one virtual address in the range, the function will mark the |
904 | * corresponding HMM pfn entry with an error flag. | |
74eee180 | 905 | */ |
73231612 | 906 | long hmm_range_fault(struct hmm_range *range, bool block) |
74eee180 | 907 | { |
a3e0d41c | 908 | unsigned long start = range->start, end; |
74eee180 | 909 | struct hmm_vma_walk hmm_vma_walk; |
a3e0d41c JG |
910 | struct hmm *hmm = range->hmm; |
911 | struct vm_area_struct *vma; | |
74eee180 | 912 | struct mm_walk mm_walk; |
74eee180 JG |
913 | int ret; |
914 | ||
a3e0d41c JG |
915 | /* Check if hmm_mm_destroy() was call. */ |
916 | if (hmm->mm == NULL || hmm->dead) | |
917 | return -EFAULT; | |
704f3f2c | 918 | |
a3e0d41c JG |
919 | do { |
920 | /* If range is no longer valid force retry. */ | |
921 | if (!range->valid) { | |
922 | up_read(&hmm->mm->mmap_sem); | |
923 | return -EAGAIN; | |
924 | } | |
74eee180 | 925 | |
a3e0d41c JG |
926 | vma = find_vma(hmm->mm, start); |
927 | if (vma == NULL || (vma->vm_flags & VM_SPECIAL)) | |
928 | return -EFAULT; | |
704f3f2c | 929 | |
a3e0d41c JG |
930 | /* FIXME support hugetlb fs/dax */ |
931 | if (is_vm_hugetlb_page(vma) || vma_is_dax(vma)) { | |
932 | hmm_pfns_special(range); | |
933 | return -EINVAL; | |
934 | } | |
855ce7d2 | 935 | |
a3e0d41c JG |
936 | if (!(vma->vm_flags & VM_READ)) { |
937 | /* | |
938 | * If vma do not allow read access, then assume that it | |
939 | * does not allow write access, either. HMM does not | |
940 | * support architecture that allow write without read. | |
941 | */ | |
942 | hmm_pfns_clear(range, range->pfns, | |
943 | range->start, range->end); | |
944 | return -EPERM; | |
945 | } | |
74eee180 | 946 | |
a3e0d41c JG |
947 | range->vma = vma; |
948 | hmm_vma_walk.last = start; | |
949 | hmm_vma_walk.fault = true; | |
950 | hmm_vma_walk.block = block; | |
951 | hmm_vma_walk.range = range; | |
952 | mm_walk.private = &hmm_vma_walk; | |
953 | end = min(range->end, vma->vm_end); | |
954 | ||
955 | mm_walk.vma = vma; | |
956 | mm_walk.mm = vma->vm_mm; | |
957 | mm_walk.pte_entry = NULL; | |
958 | mm_walk.test_walk = NULL; | |
959 | mm_walk.hugetlb_entry = NULL; | |
960 | mm_walk.pmd_entry = hmm_vma_walk_pmd; | |
961 | mm_walk.pte_hole = hmm_vma_walk_hole; | |
962 | ||
963 | do { | |
964 | ret = walk_page_range(start, end, &mm_walk); | |
965 | start = hmm_vma_walk.last; | |
966 | ||
967 | /* Keep trying while the range is valid. */ | |
968 | } while (ret == -EBUSY && range->valid); | |
969 | ||
970 | if (ret) { | |
971 | unsigned long i; | |
972 | ||
973 | i = (hmm_vma_walk.last - range->start) >> PAGE_SHIFT; | |
974 | hmm_pfns_clear(range, &range->pfns[i], | |
975 | hmm_vma_walk.last, range->end); | |
976 | return ret; | |
977 | } | |
978 | start = end; | |
74eee180 | 979 | |
a3e0d41c | 980 | } while (start < range->end); |
704f3f2c | 981 | |
73231612 | 982 | return (hmm_vma_walk.last - range->start) >> PAGE_SHIFT; |
74eee180 | 983 | } |
73231612 | 984 | EXPORT_SYMBOL(hmm_range_fault); |
c0b12405 | 985 | #endif /* IS_ENABLED(CONFIG_HMM_MIRROR) */ |
4ef589dc JG |
986 | |
987 | ||
df6ad698 | 988 | #if IS_ENABLED(CONFIG_DEVICE_PRIVATE) || IS_ENABLED(CONFIG_DEVICE_PUBLIC) |
4ef589dc JG |
989 | struct page *hmm_vma_alloc_locked_page(struct vm_area_struct *vma, |
990 | unsigned long addr) | |
991 | { | |
992 | struct page *page; | |
993 | ||
994 | page = alloc_page_vma(GFP_HIGHUSER, vma, addr); | |
995 | if (!page) | |
996 | return NULL; | |
997 | lock_page(page); | |
998 | return page; | |
999 | } | |
1000 | EXPORT_SYMBOL(hmm_vma_alloc_locked_page); | |
1001 | ||
1002 | ||
1003 | static void hmm_devmem_ref_release(struct percpu_ref *ref) | |
1004 | { | |
1005 | struct hmm_devmem *devmem; | |
1006 | ||
1007 | devmem = container_of(ref, struct hmm_devmem, ref); | |
1008 | complete(&devmem->completion); | |
1009 | } | |
1010 | ||
1011 | static void hmm_devmem_ref_exit(void *data) | |
1012 | { | |
1013 | struct percpu_ref *ref = data; | |
1014 | struct hmm_devmem *devmem; | |
1015 | ||
1016 | devmem = container_of(ref, struct hmm_devmem, ref); | |
bbecd94e | 1017 | wait_for_completion(&devmem->completion); |
4ef589dc | 1018 | percpu_ref_exit(ref); |
4ef589dc JG |
1019 | } |
1020 | ||
bbecd94e | 1021 | static void hmm_devmem_ref_kill(struct percpu_ref *ref) |
4ef589dc | 1022 | { |
4ef589dc | 1023 | percpu_ref_kill(ref); |
4ef589dc JG |
1024 | } |
1025 | ||
b57e622e | 1026 | static vm_fault_t hmm_devmem_fault(struct vm_area_struct *vma, |
4ef589dc JG |
1027 | unsigned long addr, |
1028 | const struct page *page, | |
1029 | unsigned int flags, | |
1030 | pmd_t *pmdp) | |
1031 | { | |
1032 | struct hmm_devmem *devmem = page->pgmap->data; | |
1033 | ||
1034 | return devmem->ops->fault(devmem, vma, addr, page, flags, pmdp); | |
1035 | } | |
1036 | ||
1037 | static void hmm_devmem_free(struct page *page, void *data) | |
1038 | { | |
1039 | struct hmm_devmem *devmem = data; | |
1040 | ||
2fa147bd DW |
1041 | page->mapping = NULL; |
1042 | ||
4ef589dc JG |
1043 | devmem->ops->free(devmem, page); |
1044 | } | |
1045 | ||
4ef589dc JG |
1046 | /* |
1047 | * hmm_devmem_add() - hotplug ZONE_DEVICE memory for device memory | |
1048 | * | |
1049 | * @ops: memory event device driver callback (see struct hmm_devmem_ops) | |
1050 | * @device: device struct to bind the resource too | |
1051 | * @size: size in bytes of the device memory to add | |
1052 | * Returns: pointer to new hmm_devmem struct ERR_PTR otherwise | |
1053 | * | |
1054 | * This function first finds an empty range of physical address big enough to | |
1055 | * contain the new resource, and then hotplugs it as ZONE_DEVICE memory, which | |
1056 | * in turn allocates struct pages. It does not do anything beyond that; all | |
1057 | * events affecting the memory will go through the various callbacks provided | |
1058 | * by hmm_devmem_ops struct. | |
1059 | * | |
1060 | * Device driver should call this function during device initialization and | |
1061 | * is then responsible of memory management. HMM only provides helpers. | |
1062 | */ | |
1063 | struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops, | |
1064 | struct device *device, | |
1065 | unsigned long size) | |
1066 | { | |
1067 | struct hmm_devmem *devmem; | |
1068 | resource_size_t addr; | |
bbecd94e | 1069 | void *result; |
4ef589dc JG |
1070 | int ret; |
1071 | ||
e7638488 | 1072 | dev_pagemap_get_ops(); |
4ef589dc | 1073 | |
58ef15b7 | 1074 | devmem = devm_kzalloc(device, sizeof(*devmem), GFP_KERNEL); |
4ef589dc JG |
1075 | if (!devmem) |
1076 | return ERR_PTR(-ENOMEM); | |
1077 | ||
1078 | init_completion(&devmem->completion); | |
1079 | devmem->pfn_first = -1UL; | |
1080 | devmem->pfn_last = -1UL; | |
1081 | devmem->resource = NULL; | |
1082 | devmem->device = device; | |
1083 | devmem->ops = ops; | |
1084 | ||
1085 | ret = percpu_ref_init(&devmem->ref, &hmm_devmem_ref_release, | |
1086 | 0, GFP_KERNEL); | |
1087 | if (ret) | |
58ef15b7 | 1088 | return ERR_PTR(ret); |
4ef589dc | 1089 | |
58ef15b7 | 1090 | ret = devm_add_action_or_reset(device, hmm_devmem_ref_exit, &devmem->ref); |
4ef589dc | 1091 | if (ret) |
58ef15b7 | 1092 | return ERR_PTR(ret); |
4ef589dc JG |
1093 | |
1094 | size = ALIGN(size, PA_SECTION_SIZE); | |
1095 | addr = min((unsigned long)iomem_resource.end, | |
1096 | (1UL << MAX_PHYSMEM_BITS) - 1); | |
1097 | addr = addr - size + 1UL; | |
1098 | ||
1099 | /* | |
1100 | * FIXME add a new helper to quickly walk resource tree and find free | |
1101 | * range | |
1102 | * | |
1103 | * FIXME what about ioport_resource resource ? | |
1104 | */ | |
1105 | for (; addr > size && addr >= iomem_resource.start; addr -= size) { | |
1106 | ret = region_intersects(addr, size, 0, IORES_DESC_NONE); | |
1107 | if (ret != REGION_DISJOINT) | |
1108 | continue; | |
1109 | ||
1110 | devmem->resource = devm_request_mem_region(device, addr, size, | |
1111 | dev_name(device)); | |
58ef15b7 DW |
1112 | if (!devmem->resource) |
1113 | return ERR_PTR(-ENOMEM); | |
4ef589dc JG |
1114 | break; |
1115 | } | |
58ef15b7 DW |
1116 | if (!devmem->resource) |
1117 | return ERR_PTR(-ERANGE); | |
4ef589dc JG |
1118 | |
1119 | devmem->resource->desc = IORES_DESC_DEVICE_PRIVATE_MEMORY; | |
1120 | devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT; | |
1121 | devmem->pfn_last = devmem->pfn_first + | |
1122 | (resource_size(devmem->resource) >> PAGE_SHIFT); | |
063a7d1d | 1123 | devmem->page_fault = hmm_devmem_fault; |
4ef589dc | 1124 | |
bbecd94e DW |
1125 | devmem->pagemap.type = MEMORY_DEVICE_PRIVATE; |
1126 | devmem->pagemap.res = *devmem->resource; | |
bbecd94e DW |
1127 | devmem->pagemap.page_free = hmm_devmem_free; |
1128 | devmem->pagemap.altmap_valid = false; | |
1129 | devmem->pagemap.ref = &devmem->ref; | |
1130 | devmem->pagemap.data = devmem; | |
1131 | devmem->pagemap.kill = hmm_devmem_ref_kill; | |
4ef589dc | 1132 | |
bbecd94e DW |
1133 | result = devm_memremap_pages(devmem->device, &devmem->pagemap); |
1134 | if (IS_ERR(result)) | |
1135 | return result; | |
4ef589dc | 1136 | return devmem; |
4ef589dc | 1137 | } |
02917e9f | 1138 | EXPORT_SYMBOL_GPL(hmm_devmem_add); |
4ef589dc | 1139 | |
d3df0a42 JG |
1140 | struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops, |
1141 | struct device *device, | |
1142 | struct resource *res) | |
1143 | { | |
1144 | struct hmm_devmem *devmem; | |
bbecd94e | 1145 | void *result; |
d3df0a42 JG |
1146 | int ret; |
1147 | ||
1148 | if (res->desc != IORES_DESC_DEVICE_PUBLIC_MEMORY) | |
1149 | return ERR_PTR(-EINVAL); | |
1150 | ||
e7638488 | 1151 | dev_pagemap_get_ops(); |
d3df0a42 | 1152 | |
58ef15b7 | 1153 | devmem = devm_kzalloc(device, sizeof(*devmem), GFP_KERNEL); |
d3df0a42 JG |
1154 | if (!devmem) |
1155 | return ERR_PTR(-ENOMEM); | |
1156 | ||
1157 | init_completion(&devmem->completion); | |
1158 | devmem->pfn_first = -1UL; | |
1159 | devmem->pfn_last = -1UL; | |
1160 | devmem->resource = res; | |
1161 | devmem->device = device; | |
1162 | devmem->ops = ops; | |
1163 | ||
1164 | ret = percpu_ref_init(&devmem->ref, &hmm_devmem_ref_release, | |
1165 | 0, GFP_KERNEL); | |
1166 | if (ret) | |
58ef15b7 | 1167 | return ERR_PTR(ret); |
d3df0a42 | 1168 | |
58ef15b7 DW |
1169 | ret = devm_add_action_or_reset(device, hmm_devmem_ref_exit, |
1170 | &devmem->ref); | |
d3df0a42 | 1171 | if (ret) |
58ef15b7 | 1172 | return ERR_PTR(ret); |
d3df0a42 JG |
1173 | |
1174 | devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT; | |
1175 | devmem->pfn_last = devmem->pfn_first + | |
1176 | (resource_size(devmem->resource) >> PAGE_SHIFT); | |
063a7d1d | 1177 | devmem->page_fault = hmm_devmem_fault; |
d3df0a42 | 1178 | |
bbecd94e DW |
1179 | devmem->pagemap.type = MEMORY_DEVICE_PUBLIC; |
1180 | devmem->pagemap.res = *devmem->resource; | |
bbecd94e DW |
1181 | devmem->pagemap.page_free = hmm_devmem_free; |
1182 | devmem->pagemap.altmap_valid = false; | |
1183 | devmem->pagemap.ref = &devmem->ref; | |
1184 | devmem->pagemap.data = devmem; | |
1185 | devmem->pagemap.kill = hmm_devmem_ref_kill; | |
d3df0a42 | 1186 | |
bbecd94e DW |
1187 | result = devm_memremap_pages(devmem->device, &devmem->pagemap); |
1188 | if (IS_ERR(result)) | |
1189 | return result; | |
d3df0a42 | 1190 | return devmem; |
d3df0a42 | 1191 | } |
02917e9f | 1192 | EXPORT_SYMBOL_GPL(hmm_devmem_add_resource); |
d3df0a42 | 1193 | |
858b54da JG |
1194 | /* |
1195 | * A device driver that wants to handle multiple devices memory through a | |
1196 | * single fake device can use hmm_device to do so. This is purely a helper | |
1197 | * and it is not needed to make use of any HMM functionality. | |
1198 | */ | |
1199 | #define HMM_DEVICE_MAX 256 | |
1200 | ||
1201 | static DECLARE_BITMAP(hmm_device_mask, HMM_DEVICE_MAX); | |
1202 | static DEFINE_SPINLOCK(hmm_device_lock); | |
1203 | static struct class *hmm_device_class; | |
1204 | static dev_t hmm_device_devt; | |
1205 | ||
1206 | static void hmm_device_release(struct device *device) | |
1207 | { | |
1208 | struct hmm_device *hmm_device; | |
1209 | ||
1210 | hmm_device = container_of(device, struct hmm_device, device); | |
1211 | spin_lock(&hmm_device_lock); | |
1212 | clear_bit(hmm_device->minor, hmm_device_mask); | |
1213 | spin_unlock(&hmm_device_lock); | |
1214 | ||
1215 | kfree(hmm_device); | |
1216 | } | |
1217 | ||
1218 | struct hmm_device *hmm_device_new(void *drvdata) | |
1219 | { | |
1220 | struct hmm_device *hmm_device; | |
1221 | ||
1222 | hmm_device = kzalloc(sizeof(*hmm_device), GFP_KERNEL); | |
1223 | if (!hmm_device) | |
1224 | return ERR_PTR(-ENOMEM); | |
1225 | ||
1226 | spin_lock(&hmm_device_lock); | |
1227 | hmm_device->minor = find_first_zero_bit(hmm_device_mask, HMM_DEVICE_MAX); | |
1228 | if (hmm_device->minor >= HMM_DEVICE_MAX) { | |
1229 | spin_unlock(&hmm_device_lock); | |
1230 | kfree(hmm_device); | |
1231 | return ERR_PTR(-EBUSY); | |
1232 | } | |
1233 | set_bit(hmm_device->minor, hmm_device_mask); | |
1234 | spin_unlock(&hmm_device_lock); | |
1235 | ||
1236 | dev_set_name(&hmm_device->device, "hmm_device%d", hmm_device->minor); | |
1237 | hmm_device->device.devt = MKDEV(MAJOR(hmm_device_devt), | |
1238 | hmm_device->minor); | |
1239 | hmm_device->device.release = hmm_device_release; | |
1240 | dev_set_drvdata(&hmm_device->device, drvdata); | |
1241 | hmm_device->device.class = hmm_device_class; | |
1242 | device_initialize(&hmm_device->device); | |
1243 | ||
1244 | return hmm_device; | |
1245 | } | |
1246 | EXPORT_SYMBOL(hmm_device_new); | |
1247 | ||
1248 | void hmm_device_put(struct hmm_device *hmm_device) | |
1249 | { | |
1250 | put_device(&hmm_device->device); | |
1251 | } | |
1252 | EXPORT_SYMBOL(hmm_device_put); | |
1253 | ||
1254 | static int __init hmm_init(void) | |
1255 | { | |
1256 | int ret; | |
1257 | ||
1258 | ret = alloc_chrdev_region(&hmm_device_devt, 0, | |
1259 | HMM_DEVICE_MAX, | |
1260 | "hmm_device"); | |
1261 | if (ret) | |
1262 | return ret; | |
1263 | ||
1264 | hmm_device_class = class_create(THIS_MODULE, "hmm_device"); | |
1265 | if (IS_ERR(hmm_device_class)) { | |
1266 | unregister_chrdev_region(hmm_device_devt, HMM_DEVICE_MAX); | |
1267 | return PTR_ERR(hmm_device_class); | |
1268 | } | |
1269 | return 0; | |
1270 | } | |
1271 | ||
1272 | device_initcall(hmm_init); | |
df6ad698 | 1273 | #endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */ |