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b2ef9f5a RC |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * This is a module to test the HMM (Heterogeneous Memory Management) | |
4 | * mirror and zone device private memory migration APIs of the kernel. | |
5 | * Userspace programs can register with the driver to mirror their own address | |
6 | * space and can use the device to read/write any valid virtual address. | |
7 | */ | |
8 | #include <linux/init.h> | |
9 | #include <linux/fs.h> | |
10 | #include <linux/mm.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/cdev.h> | |
14 | #include <linux/device.h> | |
15 | #include <linux/mutex.h> | |
16 | #include <linux/rwsem.h> | |
17 | #include <linux/sched.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/highmem.h> | |
20 | #include <linux/delay.h> | |
21 | #include <linux/pagemap.h> | |
22 | #include <linux/hmm.h> | |
23 | #include <linux/vmalloc.h> | |
24 | #include <linux/swap.h> | |
25 | #include <linux/swapops.h> | |
26 | #include <linux/sched/mm.h> | |
27 | #include <linux/platform_device.h> | |
b659baea | 28 | #include <linux/rmap.h> |
b2ef9f5a RC |
29 | |
30 | #include "test_hmm_uapi.h" | |
31 | ||
32 | #define DMIRROR_NDEVICES 2 | |
33 | #define DMIRROR_RANGE_FAULT_TIMEOUT 1000 | |
34 | #define DEVMEM_CHUNK_SIZE (256 * 1024 * 1024U) | |
35 | #define DEVMEM_CHUNKS_RESERVE 16 | |
36 | ||
37 | static const struct dev_pagemap_ops dmirror_devmem_ops; | |
38 | static const struct mmu_interval_notifier_ops dmirror_min_ops; | |
39 | static dev_t dmirror_dev; | |
b2ef9f5a RC |
40 | |
41 | struct dmirror_device; | |
42 | ||
43 | struct dmirror_bounce { | |
44 | void *ptr; | |
45 | unsigned long size; | |
46 | unsigned long addr; | |
47 | unsigned long cpages; | |
48 | }; | |
49 | ||
b659baea | 50 | #define DPT_XA_TAG_ATOMIC 1UL |
b2ef9f5a RC |
51 | #define DPT_XA_TAG_WRITE 3UL |
52 | ||
53 | /* | |
54 | * Data structure to track address ranges and register for mmu interval | |
55 | * notifier updates. | |
56 | */ | |
57 | struct dmirror_interval { | |
58 | struct mmu_interval_notifier notifier; | |
59 | struct dmirror *dmirror; | |
60 | }; | |
61 | ||
62 | /* | |
63 | * Data attached to the open device file. | |
64 | * Note that it might be shared after a fork(). | |
65 | */ | |
66 | struct dmirror { | |
67 | struct dmirror_device *mdevice; | |
68 | struct xarray pt; | |
69 | struct mmu_interval_notifier notifier; | |
70 | struct mutex mutex; | |
71 | }; | |
72 | ||
73 | /* | |
74 | * ZONE_DEVICE pages for migration and simulating device memory. | |
75 | */ | |
76 | struct dmirror_chunk { | |
77 | struct dev_pagemap pagemap; | |
78 | struct dmirror_device *mdevice; | |
79 | }; | |
80 | ||
81 | /* | |
82 | * Per device data. | |
83 | */ | |
84 | struct dmirror_device { | |
85 | struct cdev cdevice; | |
86 | struct hmm_devmem *devmem; | |
87 | ||
88 | unsigned int devmem_capacity; | |
89 | unsigned int devmem_count; | |
90 | struct dmirror_chunk **devmem_chunks; | |
91 | struct mutex devmem_lock; /* protects the above */ | |
92 | ||
93 | unsigned long calloc; | |
94 | unsigned long cfree; | |
95 | struct page *free_pages; | |
96 | spinlock_t lock; /* protects the above */ | |
97 | }; | |
98 | ||
99 | static struct dmirror_device dmirror_devices[DMIRROR_NDEVICES]; | |
100 | ||
101 | static int dmirror_bounce_init(struct dmirror_bounce *bounce, | |
102 | unsigned long addr, | |
103 | unsigned long size) | |
104 | { | |
105 | bounce->addr = addr; | |
106 | bounce->size = size; | |
107 | bounce->cpages = 0; | |
108 | bounce->ptr = vmalloc(size); | |
109 | if (!bounce->ptr) | |
110 | return -ENOMEM; | |
111 | return 0; | |
112 | } | |
113 | ||
114 | static void dmirror_bounce_fini(struct dmirror_bounce *bounce) | |
115 | { | |
116 | vfree(bounce->ptr); | |
117 | } | |
118 | ||
119 | static int dmirror_fops_open(struct inode *inode, struct file *filp) | |
120 | { | |
121 | struct cdev *cdev = inode->i_cdev; | |
122 | struct dmirror *dmirror; | |
123 | int ret; | |
124 | ||
125 | /* Mirror this process address space */ | |
126 | dmirror = kzalloc(sizeof(*dmirror), GFP_KERNEL); | |
127 | if (dmirror == NULL) | |
128 | return -ENOMEM; | |
129 | ||
130 | dmirror->mdevice = container_of(cdev, struct dmirror_device, cdevice); | |
131 | mutex_init(&dmirror->mutex); | |
132 | xa_init(&dmirror->pt); | |
133 | ||
134 | ret = mmu_interval_notifier_insert(&dmirror->notifier, current->mm, | |
135 | 0, ULONG_MAX & PAGE_MASK, &dmirror_min_ops); | |
136 | if (ret) { | |
137 | kfree(dmirror); | |
138 | return ret; | |
139 | } | |
140 | ||
141 | filp->private_data = dmirror; | |
142 | return 0; | |
143 | } | |
144 | ||
145 | static int dmirror_fops_release(struct inode *inode, struct file *filp) | |
146 | { | |
147 | struct dmirror *dmirror = filp->private_data; | |
148 | ||
149 | mmu_interval_notifier_remove(&dmirror->notifier); | |
150 | xa_destroy(&dmirror->pt); | |
151 | kfree(dmirror); | |
152 | return 0; | |
153 | } | |
154 | ||
155 | static struct dmirror_device *dmirror_page_to_device(struct page *page) | |
156 | ||
157 | { | |
158 | return container_of(page->pgmap, struct dmirror_chunk, | |
159 | pagemap)->mdevice; | |
160 | } | |
161 | ||
162 | static int dmirror_do_fault(struct dmirror *dmirror, struct hmm_range *range) | |
163 | { | |
164 | unsigned long *pfns = range->hmm_pfns; | |
165 | unsigned long pfn; | |
166 | ||
167 | for (pfn = (range->start >> PAGE_SHIFT); | |
168 | pfn < (range->end >> PAGE_SHIFT); | |
169 | pfn++, pfns++) { | |
170 | struct page *page; | |
171 | void *entry; | |
172 | ||
173 | /* | |
174 | * Since we asked for hmm_range_fault() to populate pages, | |
175 | * it shouldn't return an error entry on success. | |
176 | */ | |
177 | WARN_ON(*pfns & HMM_PFN_ERROR); | |
178 | WARN_ON(!(*pfns & HMM_PFN_VALID)); | |
179 | ||
180 | page = hmm_pfn_to_page(*pfns); | |
181 | WARN_ON(!page); | |
182 | ||
183 | entry = page; | |
184 | if (*pfns & HMM_PFN_WRITE) | |
185 | entry = xa_tag_pointer(entry, DPT_XA_TAG_WRITE); | |
186 | else if (WARN_ON(range->default_flags & HMM_PFN_WRITE)) | |
187 | return -EFAULT; | |
188 | entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC); | |
189 | if (xa_is_err(entry)) | |
190 | return xa_err(entry); | |
191 | } | |
192 | ||
193 | return 0; | |
194 | } | |
195 | ||
196 | static void dmirror_do_update(struct dmirror *dmirror, unsigned long start, | |
197 | unsigned long end) | |
198 | { | |
199 | unsigned long pfn; | |
200 | void *entry; | |
201 | ||
202 | /* | |
203 | * The XArray doesn't hold references to pages since it relies on | |
204 | * the mmu notifier to clear page pointers when they become stale. | |
205 | * Therefore, it is OK to just clear the entry. | |
206 | */ | |
207 | xa_for_each_range(&dmirror->pt, pfn, entry, start >> PAGE_SHIFT, | |
208 | end >> PAGE_SHIFT) | |
209 | xa_erase(&dmirror->pt, pfn); | |
210 | } | |
211 | ||
212 | static bool dmirror_interval_invalidate(struct mmu_interval_notifier *mni, | |
213 | const struct mmu_notifier_range *range, | |
214 | unsigned long cur_seq) | |
215 | { | |
216 | struct dmirror *dmirror = container_of(mni, struct dmirror, notifier); | |
217 | ||
7d17e83a RC |
218 | /* |
219 | * Ignore invalidation callbacks for device private pages since | |
220 | * the invalidation is handled as part of the migration process. | |
221 | */ | |
222 | if (range->event == MMU_NOTIFY_MIGRATE && | |
6b49bf6d | 223 | range->owner == dmirror->mdevice) |
7d17e83a RC |
224 | return true; |
225 | ||
b2ef9f5a RC |
226 | if (mmu_notifier_range_blockable(range)) |
227 | mutex_lock(&dmirror->mutex); | |
228 | else if (!mutex_trylock(&dmirror->mutex)) | |
229 | return false; | |
230 | ||
231 | mmu_interval_set_seq(mni, cur_seq); | |
232 | dmirror_do_update(dmirror, range->start, range->end); | |
233 | ||
234 | mutex_unlock(&dmirror->mutex); | |
235 | return true; | |
236 | } | |
237 | ||
238 | static const struct mmu_interval_notifier_ops dmirror_min_ops = { | |
239 | .invalidate = dmirror_interval_invalidate, | |
240 | }; | |
241 | ||
242 | static int dmirror_range_fault(struct dmirror *dmirror, | |
243 | struct hmm_range *range) | |
244 | { | |
245 | struct mm_struct *mm = dmirror->notifier.mm; | |
246 | unsigned long timeout = | |
247 | jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT); | |
248 | int ret; | |
249 | ||
250 | while (true) { | |
251 | if (time_after(jiffies, timeout)) { | |
252 | ret = -EBUSY; | |
253 | goto out; | |
254 | } | |
255 | ||
256 | range->notifier_seq = mmu_interval_read_begin(range->notifier); | |
89154dd5 | 257 | mmap_read_lock(mm); |
b2ef9f5a | 258 | ret = hmm_range_fault(range); |
89154dd5 | 259 | mmap_read_unlock(mm); |
b2ef9f5a RC |
260 | if (ret) { |
261 | if (ret == -EBUSY) | |
262 | continue; | |
263 | goto out; | |
264 | } | |
265 | ||
266 | mutex_lock(&dmirror->mutex); | |
267 | if (mmu_interval_read_retry(range->notifier, | |
268 | range->notifier_seq)) { | |
269 | mutex_unlock(&dmirror->mutex); | |
270 | continue; | |
271 | } | |
272 | break; | |
273 | } | |
274 | ||
275 | ret = dmirror_do_fault(dmirror, range); | |
276 | ||
277 | mutex_unlock(&dmirror->mutex); | |
278 | out: | |
279 | return ret; | |
280 | } | |
281 | ||
282 | static int dmirror_fault(struct dmirror *dmirror, unsigned long start, | |
283 | unsigned long end, bool write) | |
284 | { | |
285 | struct mm_struct *mm = dmirror->notifier.mm; | |
286 | unsigned long addr; | |
287 | unsigned long pfns[64]; | |
288 | struct hmm_range range = { | |
289 | .notifier = &dmirror->notifier, | |
290 | .hmm_pfns = pfns, | |
291 | .pfn_flags_mask = 0, | |
292 | .default_flags = | |
293 | HMM_PFN_REQ_FAULT | (write ? HMM_PFN_REQ_WRITE : 0), | |
294 | .dev_private_owner = dmirror->mdevice, | |
295 | }; | |
296 | int ret = 0; | |
297 | ||
298 | /* Since the mm is for the mirrored process, get a reference first. */ | |
299 | if (!mmget_not_zero(mm)) | |
300 | return 0; | |
301 | ||
302 | for (addr = start; addr < end; addr = range.end) { | |
303 | range.start = addr; | |
304 | range.end = min(addr + (ARRAY_SIZE(pfns) << PAGE_SHIFT), end); | |
305 | ||
306 | ret = dmirror_range_fault(dmirror, &range); | |
307 | if (ret) | |
308 | break; | |
309 | } | |
310 | ||
311 | mmput(mm); | |
312 | return ret; | |
313 | } | |
314 | ||
315 | static int dmirror_do_read(struct dmirror *dmirror, unsigned long start, | |
316 | unsigned long end, struct dmirror_bounce *bounce) | |
317 | { | |
318 | unsigned long pfn; | |
319 | void *ptr; | |
320 | ||
321 | ptr = bounce->ptr + ((start - bounce->addr) & PAGE_MASK); | |
322 | ||
323 | for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) { | |
324 | void *entry; | |
325 | struct page *page; | |
326 | void *tmp; | |
327 | ||
328 | entry = xa_load(&dmirror->pt, pfn); | |
329 | page = xa_untag_pointer(entry); | |
330 | if (!page) | |
331 | return -ENOENT; | |
332 | ||
333 | tmp = kmap(page); | |
334 | memcpy(ptr, tmp, PAGE_SIZE); | |
335 | kunmap(page); | |
336 | ||
337 | ptr += PAGE_SIZE; | |
338 | bounce->cpages++; | |
339 | } | |
340 | ||
341 | return 0; | |
342 | } | |
343 | ||
344 | static int dmirror_read(struct dmirror *dmirror, struct hmm_dmirror_cmd *cmd) | |
345 | { | |
346 | struct dmirror_bounce bounce; | |
347 | unsigned long start, end; | |
348 | unsigned long size = cmd->npages << PAGE_SHIFT; | |
349 | int ret; | |
350 | ||
351 | start = cmd->addr; | |
352 | end = start + size; | |
353 | if (end < start) | |
354 | return -EINVAL; | |
355 | ||
356 | ret = dmirror_bounce_init(&bounce, start, size); | |
357 | if (ret) | |
358 | return ret; | |
359 | ||
360 | while (1) { | |
361 | mutex_lock(&dmirror->mutex); | |
362 | ret = dmirror_do_read(dmirror, start, end, &bounce); | |
363 | mutex_unlock(&dmirror->mutex); | |
364 | if (ret != -ENOENT) | |
365 | break; | |
366 | ||
367 | start = cmd->addr + (bounce.cpages << PAGE_SHIFT); | |
368 | ret = dmirror_fault(dmirror, start, end, false); | |
369 | if (ret) | |
370 | break; | |
371 | cmd->faults++; | |
372 | } | |
373 | ||
374 | if (ret == 0) { | |
375 | if (copy_to_user(u64_to_user_ptr(cmd->ptr), bounce.ptr, | |
376 | bounce.size)) | |
377 | ret = -EFAULT; | |
378 | } | |
379 | cmd->cpages = bounce.cpages; | |
380 | dmirror_bounce_fini(&bounce); | |
381 | return ret; | |
382 | } | |
383 | ||
384 | static int dmirror_do_write(struct dmirror *dmirror, unsigned long start, | |
385 | unsigned long end, struct dmirror_bounce *bounce) | |
386 | { | |
387 | unsigned long pfn; | |
388 | void *ptr; | |
389 | ||
390 | ptr = bounce->ptr + ((start - bounce->addr) & PAGE_MASK); | |
391 | ||
392 | for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) { | |
393 | void *entry; | |
394 | struct page *page; | |
395 | void *tmp; | |
396 | ||
397 | entry = xa_load(&dmirror->pt, pfn); | |
398 | page = xa_untag_pointer(entry); | |
399 | if (!page || xa_pointer_tag(entry) != DPT_XA_TAG_WRITE) | |
400 | return -ENOENT; | |
401 | ||
402 | tmp = kmap(page); | |
403 | memcpy(tmp, ptr, PAGE_SIZE); | |
404 | kunmap(page); | |
405 | ||
406 | ptr += PAGE_SIZE; | |
407 | bounce->cpages++; | |
408 | } | |
409 | ||
410 | return 0; | |
411 | } | |
412 | ||
413 | static int dmirror_write(struct dmirror *dmirror, struct hmm_dmirror_cmd *cmd) | |
414 | { | |
415 | struct dmirror_bounce bounce; | |
416 | unsigned long start, end; | |
417 | unsigned long size = cmd->npages << PAGE_SHIFT; | |
418 | int ret; | |
419 | ||
420 | start = cmd->addr; | |
421 | end = start + size; | |
422 | if (end < start) | |
423 | return -EINVAL; | |
424 | ||
425 | ret = dmirror_bounce_init(&bounce, start, size); | |
426 | if (ret) | |
427 | return ret; | |
428 | if (copy_from_user(bounce.ptr, u64_to_user_ptr(cmd->ptr), | |
429 | bounce.size)) { | |
430 | ret = -EFAULT; | |
431 | goto fini; | |
432 | } | |
433 | ||
434 | while (1) { | |
435 | mutex_lock(&dmirror->mutex); | |
436 | ret = dmirror_do_write(dmirror, start, end, &bounce); | |
437 | mutex_unlock(&dmirror->mutex); | |
438 | if (ret != -ENOENT) | |
439 | break; | |
440 | ||
441 | start = cmd->addr + (bounce.cpages << PAGE_SHIFT); | |
442 | ret = dmirror_fault(dmirror, start, end, true); | |
443 | if (ret) | |
444 | break; | |
445 | cmd->faults++; | |
446 | } | |
447 | ||
448 | fini: | |
449 | cmd->cpages = bounce.cpages; | |
450 | dmirror_bounce_fini(&bounce); | |
451 | return ret; | |
452 | } | |
453 | ||
454 | static bool dmirror_allocate_chunk(struct dmirror_device *mdevice, | |
455 | struct page **ppage) | |
456 | { | |
457 | struct dmirror_chunk *devmem; | |
458 | struct resource *res; | |
459 | unsigned long pfn; | |
460 | unsigned long pfn_first; | |
461 | unsigned long pfn_last; | |
462 | void *ptr; | |
463 | ||
a4574f63 DW |
464 | devmem = kzalloc(sizeof(*devmem), GFP_KERNEL); |
465 | if (!devmem) | |
f3c9d0a3 | 466 | return false; |
a4574f63 DW |
467 | |
468 | res = request_free_mem_region(&iomem_resource, DEVMEM_CHUNK_SIZE, | |
469 | "hmm_dmirror"); | |
470 | if (IS_ERR(res)) | |
471 | goto err_devmem; | |
472 | ||
473 | devmem->pagemap.type = MEMORY_DEVICE_PRIVATE; | |
474 | devmem->pagemap.range.start = res->start; | |
475 | devmem->pagemap.range.end = res->end; | |
b7b3c01b | 476 | devmem->pagemap.nr_range = 1; |
a4574f63 DW |
477 | devmem->pagemap.ops = &dmirror_devmem_ops; |
478 | devmem->pagemap.owner = mdevice; | |
479 | ||
b2ef9f5a RC |
480 | mutex_lock(&mdevice->devmem_lock); |
481 | ||
482 | if (mdevice->devmem_count == mdevice->devmem_capacity) { | |
483 | struct dmirror_chunk **new_chunks; | |
484 | unsigned int new_capacity; | |
485 | ||
486 | new_capacity = mdevice->devmem_capacity + | |
487 | DEVMEM_CHUNKS_RESERVE; | |
488 | new_chunks = krealloc(mdevice->devmem_chunks, | |
489 | sizeof(new_chunks[0]) * new_capacity, | |
490 | GFP_KERNEL); | |
491 | if (!new_chunks) | |
a4574f63 | 492 | goto err_release; |
b2ef9f5a RC |
493 | mdevice->devmem_capacity = new_capacity; |
494 | mdevice->devmem_chunks = new_chunks; | |
495 | } | |
496 | ||
b2ef9f5a RC |
497 | ptr = memremap_pages(&devmem->pagemap, numa_node_id()); |
498 | if (IS_ERR(ptr)) | |
a4574f63 | 499 | goto err_release; |
b2ef9f5a RC |
500 | |
501 | devmem->mdevice = mdevice; | |
a4574f63 DW |
502 | pfn_first = devmem->pagemap.range.start >> PAGE_SHIFT; |
503 | pfn_last = pfn_first + (range_len(&devmem->pagemap.range) >> PAGE_SHIFT); | |
b2ef9f5a RC |
504 | mdevice->devmem_chunks[mdevice->devmem_count++] = devmem; |
505 | ||
506 | mutex_unlock(&mdevice->devmem_lock); | |
507 | ||
508 | pr_info("added new %u MB chunk (total %u chunks, %u MB) PFNs [0x%lx 0x%lx)\n", | |
509 | DEVMEM_CHUNK_SIZE / (1024 * 1024), | |
510 | mdevice->devmem_count, | |
511 | mdevice->devmem_count * (DEVMEM_CHUNK_SIZE / (1024 * 1024)), | |
512 | pfn_first, pfn_last); | |
513 | ||
514 | spin_lock(&mdevice->lock); | |
515 | for (pfn = pfn_first; pfn < pfn_last; pfn++) { | |
516 | struct page *page = pfn_to_page(pfn); | |
517 | ||
518 | page->zone_device_data = mdevice->free_pages; | |
519 | mdevice->free_pages = page; | |
520 | } | |
521 | if (ppage) { | |
522 | *ppage = mdevice->free_pages; | |
523 | mdevice->free_pages = (*ppage)->zone_device_data; | |
524 | mdevice->calloc++; | |
525 | } | |
526 | spin_unlock(&mdevice->lock); | |
527 | ||
528 | return true; | |
529 | ||
b2ef9f5a | 530 | err_release: |
b2ef9f5a | 531 | mutex_unlock(&mdevice->devmem_lock); |
a4574f63 DW |
532 | release_mem_region(devmem->pagemap.range.start, range_len(&devmem->pagemap.range)); |
533 | err_devmem: | |
534 | kfree(devmem); | |
535 | ||
b2ef9f5a RC |
536 | return false; |
537 | } | |
538 | ||
539 | static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice) | |
540 | { | |
541 | struct page *dpage = NULL; | |
542 | struct page *rpage; | |
543 | ||
544 | /* | |
545 | * This is a fake device so we alloc real system memory to store | |
546 | * our device memory. | |
547 | */ | |
548 | rpage = alloc_page(GFP_HIGHUSER); | |
549 | if (!rpage) | |
550 | return NULL; | |
551 | ||
552 | spin_lock(&mdevice->lock); | |
553 | ||
554 | if (mdevice->free_pages) { | |
555 | dpage = mdevice->free_pages; | |
556 | mdevice->free_pages = dpage->zone_device_data; | |
557 | mdevice->calloc++; | |
558 | spin_unlock(&mdevice->lock); | |
559 | } else { | |
560 | spin_unlock(&mdevice->lock); | |
561 | if (!dmirror_allocate_chunk(mdevice, &dpage)) | |
562 | goto error; | |
563 | } | |
564 | ||
565 | dpage->zone_device_data = rpage; | |
566 | get_page(dpage); | |
567 | lock_page(dpage); | |
568 | return dpage; | |
569 | ||
570 | error: | |
571 | __free_page(rpage); | |
572 | return NULL; | |
573 | } | |
574 | ||
575 | static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args, | |
576 | struct dmirror *dmirror) | |
577 | { | |
578 | struct dmirror_device *mdevice = dmirror->mdevice; | |
579 | const unsigned long *src = args->src; | |
580 | unsigned long *dst = args->dst; | |
581 | unsigned long addr; | |
582 | ||
583 | for (addr = args->start; addr < args->end; addr += PAGE_SIZE, | |
584 | src++, dst++) { | |
585 | struct page *spage; | |
586 | struct page *dpage; | |
587 | struct page *rpage; | |
588 | ||
589 | if (!(*src & MIGRATE_PFN_MIGRATE)) | |
590 | continue; | |
591 | ||
592 | /* | |
593 | * Note that spage might be NULL which is OK since it is an | |
594 | * unallocated pte_none() or read-only zero page. | |
595 | */ | |
596 | spage = migrate_pfn_to_page(*src); | |
597 | ||
b2ef9f5a RC |
598 | dpage = dmirror_devmem_alloc_page(mdevice); |
599 | if (!dpage) | |
600 | continue; | |
601 | ||
602 | rpage = dpage->zone_device_data; | |
603 | if (spage) | |
604 | copy_highpage(rpage, spage); | |
605 | else | |
606 | clear_highpage(rpage); | |
607 | ||
608 | /* | |
609 | * Normally, a device would use the page->zone_device_data to | |
610 | * point to the mirror but here we use it to hold the page for | |
611 | * the simulated device memory and that page holds the pointer | |
612 | * to the mirror. | |
613 | */ | |
614 | rpage->zone_device_data = dmirror; | |
615 | ||
616 | *dst = migrate_pfn(page_to_pfn(dpage)) | | |
617 | MIGRATE_PFN_LOCKED; | |
618 | if ((*src & MIGRATE_PFN_WRITE) || | |
619 | (!spage && args->vma->vm_flags & VM_WRITE)) | |
620 | *dst |= MIGRATE_PFN_WRITE; | |
621 | } | |
622 | } | |
623 | ||
b659baea AP |
624 | static int dmirror_check_atomic(struct dmirror *dmirror, unsigned long start, |
625 | unsigned long end) | |
626 | { | |
627 | unsigned long pfn; | |
628 | ||
629 | for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) { | |
630 | void *entry; | |
b659baea AP |
631 | |
632 | entry = xa_load(&dmirror->pt, pfn); | |
b659baea AP |
633 | if (xa_pointer_tag(entry) == DPT_XA_TAG_ATOMIC) |
634 | return -EPERM; | |
635 | } | |
636 | ||
637 | return 0; | |
638 | } | |
639 | ||
640 | static int dmirror_atomic_map(unsigned long start, unsigned long end, | |
641 | struct page **pages, struct dmirror *dmirror) | |
642 | { | |
643 | unsigned long pfn, mapped = 0; | |
644 | int i; | |
645 | ||
646 | /* Map the migrated pages into the device's page tables. */ | |
647 | mutex_lock(&dmirror->mutex); | |
648 | ||
649 | for (i = 0, pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++, i++) { | |
650 | void *entry; | |
651 | ||
652 | if (!pages[i]) | |
653 | continue; | |
654 | ||
655 | entry = pages[i]; | |
656 | entry = xa_tag_pointer(entry, DPT_XA_TAG_ATOMIC); | |
657 | entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC); | |
658 | if (xa_is_err(entry)) { | |
659 | mutex_unlock(&dmirror->mutex); | |
660 | return xa_err(entry); | |
661 | } | |
662 | ||
663 | mapped++; | |
664 | } | |
665 | ||
666 | mutex_unlock(&dmirror->mutex); | |
667 | return mapped; | |
668 | } | |
669 | ||
b2ef9f5a RC |
670 | static int dmirror_migrate_finalize_and_map(struct migrate_vma *args, |
671 | struct dmirror *dmirror) | |
672 | { | |
673 | unsigned long start = args->start; | |
674 | unsigned long end = args->end; | |
675 | const unsigned long *src = args->src; | |
676 | const unsigned long *dst = args->dst; | |
677 | unsigned long pfn; | |
678 | ||
679 | /* Map the migrated pages into the device's page tables. */ | |
680 | mutex_lock(&dmirror->mutex); | |
681 | ||
682 | for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++, | |
683 | src++, dst++) { | |
684 | struct page *dpage; | |
685 | void *entry; | |
686 | ||
687 | if (!(*src & MIGRATE_PFN_MIGRATE)) | |
688 | continue; | |
689 | ||
690 | dpage = migrate_pfn_to_page(*dst); | |
691 | if (!dpage) | |
692 | continue; | |
693 | ||
694 | /* | |
695 | * Store the page that holds the data so the page table | |
696 | * doesn't have to deal with ZONE_DEVICE private pages. | |
697 | */ | |
698 | entry = dpage->zone_device_data; | |
699 | if (*dst & MIGRATE_PFN_WRITE) | |
700 | entry = xa_tag_pointer(entry, DPT_XA_TAG_WRITE); | |
701 | entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC); | |
702 | if (xa_is_err(entry)) { | |
703 | mutex_unlock(&dmirror->mutex); | |
704 | return xa_err(entry); | |
705 | } | |
706 | } | |
707 | ||
708 | mutex_unlock(&dmirror->mutex); | |
709 | return 0; | |
710 | } | |
711 | ||
b659baea AP |
712 | static int dmirror_exclusive(struct dmirror *dmirror, |
713 | struct hmm_dmirror_cmd *cmd) | |
714 | { | |
715 | unsigned long start, end, addr; | |
716 | unsigned long size = cmd->npages << PAGE_SHIFT; | |
717 | struct mm_struct *mm = dmirror->notifier.mm; | |
718 | struct page *pages[64]; | |
719 | struct dmirror_bounce bounce; | |
720 | unsigned long next; | |
721 | int ret; | |
722 | ||
723 | start = cmd->addr; | |
724 | end = start + size; | |
725 | if (end < start) | |
726 | return -EINVAL; | |
727 | ||
728 | /* Since the mm is for the mirrored process, get a reference first. */ | |
729 | if (!mmget_not_zero(mm)) | |
730 | return -EINVAL; | |
731 | ||
732 | mmap_read_lock(mm); | |
733 | for (addr = start; addr < end; addr = next) { | |
734 | unsigned long mapped; | |
735 | int i; | |
736 | ||
737 | if (end < addr + (ARRAY_SIZE(pages) << PAGE_SHIFT)) | |
738 | next = end; | |
739 | else | |
740 | next = addr + (ARRAY_SIZE(pages) << PAGE_SHIFT); | |
741 | ||
742 | ret = make_device_exclusive_range(mm, addr, next, pages, NULL); | |
743 | mapped = dmirror_atomic_map(addr, next, pages, dmirror); | |
744 | for (i = 0; i < ret; i++) { | |
745 | if (pages[i]) { | |
746 | unlock_page(pages[i]); | |
747 | put_page(pages[i]); | |
748 | } | |
749 | } | |
750 | ||
751 | if (addr + (mapped << PAGE_SHIFT) < next) { | |
752 | mmap_read_unlock(mm); | |
753 | mmput(mm); | |
754 | return -EBUSY; | |
755 | } | |
756 | } | |
757 | mmap_read_unlock(mm); | |
758 | mmput(mm); | |
759 | ||
760 | /* Return the migrated data for verification. */ | |
761 | ret = dmirror_bounce_init(&bounce, start, size); | |
762 | if (ret) | |
763 | return ret; | |
764 | mutex_lock(&dmirror->mutex); | |
765 | ret = dmirror_do_read(dmirror, start, end, &bounce); | |
766 | mutex_unlock(&dmirror->mutex); | |
767 | if (ret == 0) { | |
768 | if (copy_to_user(u64_to_user_ptr(cmd->ptr), bounce.ptr, | |
769 | bounce.size)) | |
770 | ret = -EFAULT; | |
771 | } | |
772 | ||
773 | cmd->cpages = bounce.cpages; | |
774 | dmirror_bounce_fini(&bounce); | |
775 | return ret; | |
776 | } | |
777 | ||
b2ef9f5a RC |
778 | static int dmirror_migrate(struct dmirror *dmirror, |
779 | struct hmm_dmirror_cmd *cmd) | |
780 | { | |
781 | unsigned long start, end, addr; | |
782 | unsigned long size = cmd->npages << PAGE_SHIFT; | |
783 | struct mm_struct *mm = dmirror->notifier.mm; | |
784 | struct vm_area_struct *vma; | |
785 | unsigned long src_pfns[64]; | |
786 | unsigned long dst_pfns[64]; | |
787 | struct dmirror_bounce bounce; | |
788 | struct migrate_vma args; | |
789 | unsigned long next; | |
790 | int ret; | |
791 | ||
792 | start = cmd->addr; | |
793 | end = start + size; | |
794 | if (end < start) | |
795 | return -EINVAL; | |
796 | ||
797 | /* Since the mm is for the mirrored process, get a reference first. */ | |
798 | if (!mmget_not_zero(mm)) | |
799 | return -EINVAL; | |
800 | ||
89154dd5 | 801 | mmap_read_lock(mm); |
b2ef9f5a | 802 | for (addr = start; addr < end; addr = next) { |
46e6b31d LH |
803 | vma = vma_lookup(mm, addr); |
804 | if (!vma || !(vma->vm_flags & VM_READ)) { | |
b2ef9f5a RC |
805 | ret = -EINVAL; |
806 | goto out; | |
807 | } | |
808 | next = min(end, addr + (ARRAY_SIZE(src_pfns) << PAGE_SHIFT)); | |
809 | if (next > vma->vm_end) | |
810 | next = vma->vm_end; | |
811 | ||
812 | args.vma = vma; | |
813 | args.src = src_pfns; | |
814 | args.dst = dst_pfns; | |
815 | args.start = addr; | |
816 | args.end = next; | |
7d17e83a | 817 | args.pgmap_owner = dmirror->mdevice; |
5143192c | 818 | args.flags = MIGRATE_VMA_SELECT_SYSTEM; |
b2ef9f5a RC |
819 | ret = migrate_vma_setup(&args); |
820 | if (ret) | |
821 | goto out; | |
822 | ||
823 | dmirror_migrate_alloc_and_copy(&args, dmirror); | |
824 | migrate_vma_pages(&args); | |
825 | dmirror_migrate_finalize_and_map(&args, dmirror); | |
826 | migrate_vma_finalize(&args); | |
827 | } | |
89154dd5 | 828 | mmap_read_unlock(mm); |
b2ef9f5a RC |
829 | mmput(mm); |
830 | ||
831 | /* Return the migrated data for verification. */ | |
832 | ret = dmirror_bounce_init(&bounce, start, size); | |
833 | if (ret) | |
834 | return ret; | |
835 | mutex_lock(&dmirror->mutex); | |
836 | ret = dmirror_do_read(dmirror, start, end, &bounce); | |
837 | mutex_unlock(&dmirror->mutex); | |
838 | if (ret == 0) { | |
839 | if (copy_to_user(u64_to_user_ptr(cmd->ptr), bounce.ptr, | |
840 | bounce.size)) | |
841 | ret = -EFAULT; | |
842 | } | |
843 | cmd->cpages = bounce.cpages; | |
844 | dmirror_bounce_fini(&bounce); | |
845 | return ret; | |
846 | ||
847 | out: | |
89154dd5 | 848 | mmap_read_unlock(mm); |
b2ef9f5a RC |
849 | mmput(mm); |
850 | return ret; | |
851 | } | |
852 | ||
853 | static void dmirror_mkentry(struct dmirror *dmirror, struct hmm_range *range, | |
854 | unsigned char *perm, unsigned long entry) | |
855 | { | |
856 | struct page *page; | |
857 | ||
858 | if (entry & HMM_PFN_ERROR) { | |
859 | *perm = HMM_DMIRROR_PROT_ERROR; | |
860 | return; | |
861 | } | |
862 | if (!(entry & HMM_PFN_VALID)) { | |
863 | *perm = HMM_DMIRROR_PROT_NONE; | |
864 | return; | |
865 | } | |
866 | ||
867 | page = hmm_pfn_to_page(entry); | |
868 | if (is_device_private_page(page)) { | |
869 | /* Is the page migrated to this device or some other? */ | |
870 | if (dmirror->mdevice == dmirror_page_to_device(page)) | |
871 | *perm = HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL; | |
872 | else | |
873 | *perm = HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE; | |
874 | } else if (is_zero_pfn(page_to_pfn(page))) | |
875 | *perm = HMM_DMIRROR_PROT_ZERO; | |
876 | else | |
877 | *perm = HMM_DMIRROR_PROT_NONE; | |
878 | if (entry & HMM_PFN_WRITE) | |
879 | *perm |= HMM_DMIRROR_PROT_WRITE; | |
880 | else | |
881 | *perm |= HMM_DMIRROR_PROT_READ; | |
e478425b RC |
882 | if (hmm_pfn_to_map_order(entry) + PAGE_SHIFT == PMD_SHIFT) |
883 | *perm |= HMM_DMIRROR_PROT_PMD; | |
884 | else if (hmm_pfn_to_map_order(entry) + PAGE_SHIFT == PUD_SHIFT) | |
885 | *perm |= HMM_DMIRROR_PROT_PUD; | |
b2ef9f5a RC |
886 | } |
887 | ||
888 | static bool dmirror_snapshot_invalidate(struct mmu_interval_notifier *mni, | |
889 | const struct mmu_notifier_range *range, | |
890 | unsigned long cur_seq) | |
891 | { | |
892 | struct dmirror_interval *dmi = | |
893 | container_of(mni, struct dmirror_interval, notifier); | |
894 | struct dmirror *dmirror = dmi->dmirror; | |
895 | ||
896 | if (mmu_notifier_range_blockable(range)) | |
897 | mutex_lock(&dmirror->mutex); | |
898 | else if (!mutex_trylock(&dmirror->mutex)) | |
899 | return false; | |
900 | ||
901 | /* | |
902 | * Snapshots only need to set the sequence number since any | |
903 | * invalidation in the interval invalidates the whole snapshot. | |
904 | */ | |
905 | mmu_interval_set_seq(mni, cur_seq); | |
906 | ||
907 | mutex_unlock(&dmirror->mutex); | |
908 | return true; | |
909 | } | |
910 | ||
911 | static const struct mmu_interval_notifier_ops dmirror_mrn_ops = { | |
912 | .invalidate = dmirror_snapshot_invalidate, | |
913 | }; | |
914 | ||
915 | static int dmirror_range_snapshot(struct dmirror *dmirror, | |
916 | struct hmm_range *range, | |
917 | unsigned char *perm) | |
918 | { | |
919 | struct mm_struct *mm = dmirror->notifier.mm; | |
920 | struct dmirror_interval notifier; | |
921 | unsigned long timeout = | |
922 | jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT); | |
923 | unsigned long i; | |
924 | unsigned long n; | |
925 | int ret = 0; | |
926 | ||
927 | notifier.dmirror = dmirror; | |
928 | range->notifier = ¬ifier.notifier; | |
929 | ||
930 | ret = mmu_interval_notifier_insert(range->notifier, mm, | |
931 | range->start, range->end - range->start, | |
932 | &dmirror_mrn_ops); | |
933 | if (ret) | |
934 | return ret; | |
935 | ||
936 | while (true) { | |
937 | if (time_after(jiffies, timeout)) { | |
938 | ret = -EBUSY; | |
939 | goto out; | |
940 | } | |
941 | ||
942 | range->notifier_seq = mmu_interval_read_begin(range->notifier); | |
943 | ||
89154dd5 | 944 | mmap_read_lock(mm); |
b2ef9f5a | 945 | ret = hmm_range_fault(range); |
89154dd5 | 946 | mmap_read_unlock(mm); |
b2ef9f5a RC |
947 | if (ret) { |
948 | if (ret == -EBUSY) | |
949 | continue; | |
950 | goto out; | |
951 | } | |
952 | ||
953 | mutex_lock(&dmirror->mutex); | |
954 | if (mmu_interval_read_retry(range->notifier, | |
955 | range->notifier_seq)) { | |
956 | mutex_unlock(&dmirror->mutex); | |
957 | continue; | |
958 | } | |
959 | break; | |
960 | } | |
961 | ||
962 | n = (range->end - range->start) >> PAGE_SHIFT; | |
963 | for (i = 0; i < n; i++) | |
964 | dmirror_mkentry(dmirror, range, perm + i, range->hmm_pfns[i]); | |
965 | ||
966 | mutex_unlock(&dmirror->mutex); | |
967 | out: | |
968 | mmu_interval_notifier_remove(range->notifier); | |
969 | return ret; | |
970 | } | |
971 | ||
972 | static int dmirror_snapshot(struct dmirror *dmirror, | |
973 | struct hmm_dmirror_cmd *cmd) | |
974 | { | |
975 | struct mm_struct *mm = dmirror->notifier.mm; | |
976 | unsigned long start, end; | |
977 | unsigned long size = cmd->npages << PAGE_SHIFT; | |
978 | unsigned long addr; | |
979 | unsigned long next; | |
980 | unsigned long pfns[64]; | |
981 | unsigned char perm[64]; | |
982 | char __user *uptr; | |
983 | struct hmm_range range = { | |
984 | .hmm_pfns = pfns, | |
985 | .dev_private_owner = dmirror->mdevice, | |
986 | }; | |
987 | int ret = 0; | |
988 | ||
989 | start = cmd->addr; | |
990 | end = start + size; | |
991 | if (end < start) | |
992 | return -EINVAL; | |
993 | ||
994 | /* Since the mm is for the mirrored process, get a reference first. */ | |
995 | if (!mmget_not_zero(mm)) | |
996 | return -EINVAL; | |
997 | ||
998 | /* | |
999 | * Register a temporary notifier to detect invalidations even if it | |
1000 | * overlaps with other mmu_interval_notifiers. | |
1001 | */ | |
1002 | uptr = u64_to_user_ptr(cmd->ptr); | |
1003 | for (addr = start; addr < end; addr = next) { | |
1004 | unsigned long n; | |
1005 | ||
1006 | next = min(addr + (ARRAY_SIZE(pfns) << PAGE_SHIFT), end); | |
1007 | range.start = addr; | |
1008 | range.end = next; | |
1009 | ||
1010 | ret = dmirror_range_snapshot(dmirror, &range, perm); | |
1011 | if (ret) | |
1012 | break; | |
1013 | ||
1014 | n = (range.end - range.start) >> PAGE_SHIFT; | |
1015 | if (copy_to_user(uptr, perm, n)) { | |
1016 | ret = -EFAULT; | |
1017 | break; | |
1018 | } | |
1019 | ||
1020 | cmd->cpages += n; | |
1021 | uptr += n; | |
1022 | } | |
1023 | mmput(mm); | |
1024 | ||
1025 | return ret; | |
1026 | } | |
1027 | ||
1028 | static long dmirror_fops_unlocked_ioctl(struct file *filp, | |
1029 | unsigned int command, | |
1030 | unsigned long arg) | |
1031 | { | |
1032 | void __user *uarg = (void __user *)arg; | |
1033 | struct hmm_dmirror_cmd cmd; | |
1034 | struct dmirror *dmirror; | |
1035 | int ret; | |
1036 | ||
1037 | dmirror = filp->private_data; | |
1038 | if (!dmirror) | |
1039 | return -EINVAL; | |
1040 | ||
1041 | if (copy_from_user(&cmd, uarg, sizeof(cmd))) | |
1042 | return -EFAULT; | |
1043 | ||
1044 | if (cmd.addr & ~PAGE_MASK) | |
1045 | return -EINVAL; | |
1046 | if (cmd.addr >= (cmd.addr + (cmd.npages << PAGE_SHIFT))) | |
1047 | return -EINVAL; | |
1048 | ||
1049 | cmd.cpages = 0; | |
1050 | cmd.faults = 0; | |
1051 | ||
1052 | switch (command) { | |
1053 | case HMM_DMIRROR_READ: | |
1054 | ret = dmirror_read(dmirror, &cmd); | |
1055 | break; | |
1056 | ||
1057 | case HMM_DMIRROR_WRITE: | |
1058 | ret = dmirror_write(dmirror, &cmd); | |
1059 | break; | |
1060 | ||
1061 | case HMM_DMIRROR_MIGRATE: | |
1062 | ret = dmirror_migrate(dmirror, &cmd); | |
1063 | break; | |
1064 | ||
b659baea AP |
1065 | case HMM_DMIRROR_EXCLUSIVE: |
1066 | ret = dmirror_exclusive(dmirror, &cmd); | |
1067 | break; | |
1068 | ||
1069 | case HMM_DMIRROR_CHECK_EXCLUSIVE: | |
1070 | ret = dmirror_check_atomic(dmirror, cmd.addr, | |
1071 | cmd.addr + (cmd.npages << PAGE_SHIFT)); | |
1072 | break; | |
1073 | ||
b2ef9f5a RC |
1074 | case HMM_DMIRROR_SNAPSHOT: |
1075 | ret = dmirror_snapshot(dmirror, &cmd); | |
1076 | break; | |
1077 | ||
1078 | default: | |
1079 | return -EINVAL; | |
1080 | } | |
1081 | if (ret) | |
1082 | return ret; | |
1083 | ||
1084 | if (copy_to_user(uarg, &cmd, sizeof(cmd))) | |
1085 | return -EFAULT; | |
1086 | ||
1087 | return 0; | |
1088 | } | |
1089 | ||
1090 | static const struct file_operations dmirror_fops = { | |
1091 | .open = dmirror_fops_open, | |
1092 | .release = dmirror_fops_release, | |
1093 | .unlocked_ioctl = dmirror_fops_unlocked_ioctl, | |
1094 | .llseek = default_llseek, | |
1095 | .owner = THIS_MODULE, | |
1096 | }; | |
1097 | ||
1098 | static void dmirror_devmem_free(struct page *page) | |
1099 | { | |
1100 | struct page *rpage = page->zone_device_data; | |
1101 | struct dmirror_device *mdevice; | |
1102 | ||
1103 | if (rpage) | |
1104 | __free_page(rpage); | |
1105 | ||
1106 | mdevice = dmirror_page_to_device(page); | |
1107 | ||
1108 | spin_lock(&mdevice->lock); | |
1109 | mdevice->cfree++; | |
1110 | page->zone_device_data = mdevice->free_pages; | |
1111 | mdevice->free_pages = page; | |
1112 | spin_unlock(&mdevice->lock); | |
1113 | } | |
1114 | ||
1115 | static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args, | |
7d17e83a | 1116 | struct dmirror *dmirror) |
b2ef9f5a RC |
1117 | { |
1118 | const unsigned long *src = args->src; | |
1119 | unsigned long *dst = args->dst; | |
1120 | unsigned long start = args->start; | |
1121 | unsigned long end = args->end; | |
1122 | unsigned long addr; | |
1123 | ||
1124 | for (addr = start; addr < end; addr += PAGE_SIZE, | |
1125 | src++, dst++) { | |
1126 | struct page *dpage, *spage; | |
1127 | ||
1128 | spage = migrate_pfn_to_page(*src); | |
1129 | if (!spage || !(*src & MIGRATE_PFN_MIGRATE)) | |
1130 | continue; | |
1131 | spage = spage->zone_device_data; | |
1132 | ||
1133 | dpage = alloc_page_vma(GFP_HIGHUSER_MOVABLE, args->vma, addr); | |
1134 | if (!dpage) | |
1135 | continue; | |
1136 | ||
1137 | lock_page(dpage); | |
7d17e83a | 1138 | xa_erase(&dmirror->pt, addr >> PAGE_SHIFT); |
b2ef9f5a RC |
1139 | copy_highpage(dpage, spage); |
1140 | *dst = migrate_pfn(page_to_pfn(dpage)) | MIGRATE_PFN_LOCKED; | |
1141 | if (*src & MIGRATE_PFN_WRITE) | |
1142 | *dst |= MIGRATE_PFN_WRITE; | |
1143 | } | |
1144 | return 0; | |
1145 | } | |
1146 | ||
b2ef9f5a RC |
1147 | static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf) |
1148 | { | |
1149 | struct migrate_vma args; | |
1150 | unsigned long src_pfns; | |
1151 | unsigned long dst_pfns; | |
1152 | struct page *rpage; | |
1153 | struct dmirror *dmirror; | |
1154 | vm_fault_t ret; | |
1155 | ||
1156 | /* | |
1157 | * Normally, a device would use the page->zone_device_data to point to | |
1158 | * the mirror but here we use it to hold the page for the simulated | |
1159 | * device memory and that page holds the pointer to the mirror. | |
1160 | */ | |
1161 | rpage = vmf->page->zone_device_data; | |
1162 | dmirror = rpage->zone_device_data; | |
1163 | ||
1164 | /* FIXME demonstrate how we can adjust migrate range */ | |
1165 | args.vma = vmf->vma; | |
1166 | args.start = vmf->address; | |
1167 | args.end = args.start + PAGE_SIZE; | |
1168 | args.src = &src_pfns; | |
1169 | args.dst = &dst_pfns; | |
5143192c RC |
1170 | args.pgmap_owner = dmirror->mdevice; |
1171 | args.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE; | |
b2ef9f5a RC |
1172 | |
1173 | if (migrate_vma_setup(&args)) | |
1174 | return VM_FAULT_SIGBUS; | |
1175 | ||
7d17e83a | 1176 | ret = dmirror_devmem_fault_alloc_and_copy(&args, dmirror); |
b2ef9f5a RC |
1177 | if (ret) |
1178 | return ret; | |
1179 | migrate_vma_pages(&args); | |
7d17e83a RC |
1180 | /* |
1181 | * No device finalize step is needed since | |
1182 | * dmirror_devmem_fault_alloc_and_copy() will have already | |
1183 | * invalidated the device page table. | |
1184 | */ | |
b2ef9f5a RC |
1185 | migrate_vma_finalize(&args); |
1186 | return 0; | |
1187 | } | |
1188 | ||
1189 | static const struct dev_pagemap_ops dmirror_devmem_ops = { | |
1190 | .page_free = dmirror_devmem_free, | |
1191 | .migrate_to_ram = dmirror_devmem_fault, | |
1192 | }; | |
1193 | ||
1194 | static int dmirror_device_init(struct dmirror_device *mdevice, int id) | |
1195 | { | |
1196 | dev_t dev; | |
1197 | int ret; | |
1198 | ||
1199 | dev = MKDEV(MAJOR(dmirror_dev), id); | |
1200 | mutex_init(&mdevice->devmem_lock); | |
1201 | spin_lock_init(&mdevice->lock); | |
1202 | ||
1203 | cdev_init(&mdevice->cdevice, &dmirror_fops); | |
1204 | mdevice->cdevice.owner = THIS_MODULE; | |
1205 | ret = cdev_add(&mdevice->cdevice, dev, 1); | |
1206 | if (ret) | |
1207 | return ret; | |
1208 | ||
1209 | /* Build a list of free ZONE_DEVICE private struct pages */ | |
1210 | dmirror_allocate_chunk(mdevice, NULL); | |
1211 | ||
1212 | return 0; | |
1213 | } | |
1214 | ||
1215 | static void dmirror_device_remove(struct dmirror_device *mdevice) | |
1216 | { | |
1217 | unsigned int i; | |
1218 | ||
1219 | if (mdevice->devmem_chunks) { | |
1220 | for (i = 0; i < mdevice->devmem_count; i++) { | |
1221 | struct dmirror_chunk *devmem = | |
1222 | mdevice->devmem_chunks[i]; | |
1223 | ||
1224 | memunmap_pages(&devmem->pagemap); | |
a4574f63 DW |
1225 | release_mem_region(devmem->pagemap.range.start, |
1226 | range_len(&devmem->pagemap.range)); | |
b2ef9f5a RC |
1227 | kfree(devmem); |
1228 | } | |
1229 | kfree(mdevice->devmem_chunks); | |
1230 | } | |
1231 | ||
1232 | cdev_del(&mdevice->cdevice); | |
1233 | } | |
1234 | ||
1235 | static int __init hmm_dmirror_init(void) | |
1236 | { | |
1237 | int ret; | |
1238 | int id; | |
1239 | ||
1240 | ret = alloc_chrdev_region(&dmirror_dev, 0, DMIRROR_NDEVICES, | |
1241 | "HMM_DMIRROR"); | |
1242 | if (ret) | |
1243 | goto err_unreg; | |
1244 | ||
1245 | for (id = 0; id < DMIRROR_NDEVICES; id++) { | |
1246 | ret = dmirror_device_init(dmirror_devices + id, id); | |
1247 | if (ret) | |
1248 | goto err_chrdev; | |
1249 | } | |
1250 | ||
b2ef9f5a RC |
1251 | pr_info("HMM test module loaded. This is only for testing HMM.\n"); |
1252 | return 0; | |
1253 | ||
1254 | err_chrdev: | |
1255 | while (--id >= 0) | |
1256 | dmirror_device_remove(dmirror_devices + id); | |
1257 | unregister_chrdev_region(dmirror_dev, DMIRROR_NDEVICES); | |
1258 | err_unreg: | |
1259 | return ret; | |
1260 | } | |
1261 | ||
1262 | static void __exit hmm_dmirror_exit(void) | |
1263 | { | |
1264 | int id; | |
1265 | ||
b2ef9f5a RC |
1266 | for (id = 0; id < DMIRROR_NDEVICES; id++) |
1267 | dmirror_device_remove(dmirror_devices + id); | |
1268 | unregister_chrdev_region(dmirror_dev, DMIRROR_NDEVICES); | |
1269 | } | |
1270 | ||
1271 | module_init(hmm_dmirror_init); | |
1272 | module_exit(hmm_dmirror_exit); | |
1273 | MODULE_LICENSE("GPL"); |