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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> | |
dc90f084 | 15 | #include <linux/memremap.h> |
b2ef9f5a RC |
16 | #include <linux/mutex.h> |
17 | #include <linux/rwsem.h> | |
18 | #include <linux/sched.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/highmem.h> | |
21 | #include <linux/delay.h> | |
22 | #include <linux/pagemap.h> | |
23 | #include <linux/hmm.h> | |
24 | #include <linux/vmalloc.h> | |
25 | #include <linux/swap.h> | |
26 | #include <linux/swapops.h> | |
27 | #include <linux/sched/mm.h> | |
28 | #include <linux/platform_device.h> | |
b659baea | 29 | #include <linux/rmap.h> |
730ff521 CH |
30 | #include <linux/mmu_notifier.h> |
31 | #include <linux/migrate.h> | |
b2ef9f5a RC |
32 | |
33 | #include "test_hmm_uapi.h" | |
34 | ||
35 | #define DMIRROR_NDEVICES 2 | |
36 | #define DMIRROR_RANGE_FAULT_TIMEOUT 1000 | |
37 | #define DEVMEM_CHUNK_SIZE (256 * 1024 * 1024U) | |
38 | #define DEVMEM_CHUNKS_RESERVE 16 | |
39 | ||
40 | static const struct dev_pagemap_ops dmirror_devmem_ops; | |
41 | static const struct mmu_interval_notifier_ops dmirror_min_ops; | |
42 | static dev_t dmirror_dev; | |
b2ef9f5a RC |
43 | |
44 | struct dmirror_device; | |
45 | ||
46 | struct dmirror_bounce { | |
47 | void *ptr; | |
48 | unsigned long size; | |
49 | unsigned long addr; | |
50 | unsigned long cpages; | |
51 | }; | |
52 | ||
b659baea | 53 | #define DPT_XA_TAG_ATOMIC 1UL |
b2ef9f5a RC |
54 | #define DPT_XA_TAG_WRITE 3UL |
55 | ||
56 | /* | |
57 | * Data structure to track address ranges and register for mmu interval | |
58 | * notifier updates. | |
59 | */ | |
60 | struct dmirror_interval { | |
61 | struct mmu_interval_notifier notifier; | |
62 | struct dmirror *dmirror; | |
63 | }; | |
64 | ||
65 | /* | |
66 | * Data attached to the open device file. | |
67 | * Note that it might be shared after a fork(). | |
68 | */ | |
69 | struct dmirror { | |
70 | struct dmirror_device *mdevice; | |
71 | struct xarray pt; | |
72 | struct mmu_interval_notifier notifier; | |
73 | struct mutex mutex; | |
74 | }; | |
75 | ||
76 | /* | |
77 | * ZONE_DEVICE pages for migration and simulating device memory. | |
78 | */ | |
79 | struct dmirror_chunk { | |
80 | struct dev_pagemap pagemap; | |
81 | struct dmirror_device *mdevice; | |
82 | }; | |
83 | ||
84 | /* | |
85 | * Per device data. | |
86 | */ | |
87 | struct dmirror_device { | |
88 | struct cdev cdevice; | |
89 | struct hmm_devmem *devmem; | |
90 | ||
91 | unsigned int devmem_capacity; | |
92 | unsigned int devmem_count; | |
93 | struct dmirror_chunk **devmem_chunks; | |
94 | struct mutex devmem_lock; /* protects the above */ | |
95 | ||
96 | unsigned long calloc; | |
97 | unsigned long cfree; | |
98 | struct page *free_pages; | |
99 | spinlock_t lock; /* protects the above */ | |
100 | }; | |
101 | ||
102 | static struct dmirror_device dmirror_devices[DMIRROR_NDEVICES]; | |
103 | ||
104 | static int dmirror_bounce_init(struct dmirror_bounce *bounce, | |
105 | unsigned long addr, | |
106 | unsigned long size) | |
107 | { | |
108 | bounce->addr = addr; | |
109 | bounce->size = size; | |
110 | bounce->cpages = 0; | |
111 | bounce->ptr = vmalloc(size); | |
112 | if (!bounce->ptr) | |
113 | return -ENOMEM; | |
114 | return 0; | |
115 | } | |
116 | ||
117 | static void dmirror_bounce_fini(struct dmirror_bounce *bounce) | |
118 | { | |
119 | vfree(bounce->ptr); | |
120 | } | |
121 | ||
122 | static int dmirror_fops_open(struct inode *inode, struct file *filp) | |
123 | { | |
124 | struct cdev *cdev = inode->i_cdev; | |
125 | struct dmirror *dmirror; | |
126 | int ret; | |
127 | ||
128 | /* Mirror this process address space */ | |
129 | dmirror = kzalloc(sizeof(*dmirror), GFP_KERNEL); | |
130 | if (dmirror == NULL) | |
131 | return -ENOMEM; | |
132 | ||
133 | dmirror->mdevice = container_of(cdev, struct dmirror_device, cdevice); | |
134 | mutex_init(&dmirror->mutex); | |
135 | xa_init(&dmirror->pt); | |
136 | ||
137 | ret = mmu_interval_notifier_insert(&dmirror->notifier, current->mm, | |
138 | 0, ULONG_MAX & PAGE_MASK, &dmirror_min_ops); | |
139 | if (ret) { | |
140 | kfree(dmirror); | |
141 | return ret; | |
142 | } | |
143 | ||
144 | filp->private_data = dmirror; | |
145 | return 0; | |
146 | } | |
147 | ||
148 | static int dmirror_fops_release(struct inode *inode, struct file *filp) | |
149 | { | |
150 | struct dmirror *dmirror = filp->private_data; | |
151 | ||
152 | mmu_interval_notifier_remove(&dmirror->notifier); | |
153 | xa_destroy(&dmirror->pt); | |
154 | kfree(dmirror); | |
155 | return 0; | |
156 | } | |
157 | ||
158 | static struct dmirror_device *dmirror_page_to_device(struct page *page) | |
159 | ||
160 | { | |
161 | return container_of(page->pgmap, struct dmirror_chunk, | |
162 | pagemap)->mdevice; | |
163 | } | |
164 | ||
165 | static int dmirror_do_fault(struct dmirror *dmirror, struct hmm_range *range) | |
166 | { | |
167 | unsigned long *pfns = range->hmm_pfns; | |
168 | unsigned long pfn; | |
169 | ||
170 | for (pfn = (range->start >> PAGE_SHIFT); | |
171 | pfn < (range->end >> PAGE_SHIFT); | |
172 | pfn++, pfns++) { | |
173 | struct page *page; | |
174 | void *entry; | |
175 | ||
176 | /* | |
177 | * Since we asked for hmm_range_fault() to populate pages, | |
178 | * it shouldn't return an error entry on success. | |
179 | */ | |
180 | WARN_ON(*pfns & HMM_PFN_ERROR); | |
181 | WARN_ON(!(*pfns & HMM_PFN_VALID)); | |
182 | ||
183 | page = hmm_pfn_to_page(*pfns); | |
184 | WARN_ON(!page); | |
185 | ||
186 | entry = page; | |
187 | if (*pfns & HMM_PFN_WRITE) | |
188 | entry = xa_tag_pointer(entry, DPT_XA_TAG_WRITE); | |
189 | else if (WARN_ON(range->default_flags & HMM_PFN_WRITE)) | |
190 | return -EFAULT; | |
191 | entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC); | |
192 | if (xa_is_err(entry)) | |
193 | return xa_err(entry); | |
194 | } | |
195 | ||
196 | return 0; | |
197 | } | |
198 | ||
199 | static void dmirror_do_update(struct dmirror *dmirror, unsigned long start, | |
200 | unsigned long end) | |
201 | { | |
202 | unsigned long pfn; | |
203 | void *entry; | |
204 | ||
205 | /* | |
206 | * The XArray doesn't hold references to pages since it relies on | |
207 | * the mmu notifier to clear page pointers when they become stale. | |
208 | * Therefore, it is OK to just clear the entry. | |
209 | */ | |
210 | xa_for_each_range(&dmirror->pt, pfn, entry, start >> PAGE_SHIFT, | |
211 | end >> PAGE_SHIFT) | |
212 | xa_erase(&dmirror->pt, pfn); | |
213 | } | |
214 | ||
215 | static bool dmirror_interval_invalidate(struct mmu_interval_notifier *mni, | |
216 | const struct mmu_notifier_range *range, | |
217 | unsigned long cur_seq) | |
218 | { | |
219 | struct dmirror *dmirror = container_of(mni, struct dmirror, notifier); | |
220 | ||
7d17e83a RC |
221 | /* |
222 | * Ignore invalidation callbacks for device private pages since | |
223 | * the invalidation is handled as part of the migration process. | |
224 | */ | |
225 | if (range->event == MMU_NOTIFY_MIGRATE && | |
6b49bf6d | 226 | range->owner == dmirror->mdevice) |
7d17e83a RC |
227 | return true; |
228 | ||
b2ef9f5a RC |
229 | if (mmu_notifier_range_blockable(range)) |
230 | mutex_lock(&dmirror->mutex); | |
231 | else if (!mutex_trylock(&dmirror->mutex)) | |
232 | return false; | |
233 | ||
234 | mmu_interval_set_seq(mni, cur_seq); | |
235 | dmirror_do_update(dmirror, range->start, range->end); | |
236 | ||
237 | mutex_unlock(&dmirror->mutex); | |
238 | return true; | |
239 | } | |
240 | ||
241 | static const struct mmu_interval_notifier_ops dmirror_min_ops = { | |
242 | .invalidate = dmirror_interval_invalidate, | |
243 | }; | |
244 | ||
245 | static int dmirror_range_fault(struct dmirror *dmirror, | |
246 | struct hmm_range *range) | |
247 | { | |
248 | struct mm_struct *mm = dmirror->notifier.mm; | |
249 | unsigned long timeout = | |
250 | jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT); | |
251 | int ret; | |
252 | ||
253 | while (true) { | |
254 | if (time_after(jiffies, timeout)) { | |
255 | ret = -EBUSY; | |
256 | goto out; | |
257 | } | |
258 | ||
259 | range->notifier_seq = mmu_interval_read_begin(range->notifier); | |
89154dd5 | 260 | mmap_read_lock(mm); |
b2ef9f5a | 261 | ret = hmm_range_fault(range); |
89154dd5 | 262 | mmap_read_unlock(mm); |
b2ef9f5a RC |
263 | if (ret) { |
264 | if (ret == -EBUSY) | |
265 | continue; | |
266 | goto out; | |
267 | } | |
268 | ||
269 | mutex_lock(&dmirror->mutex); | |
270 | if (mmu_interval_read_retry(range->notifier, | |
271 | range->notifier_seq)) { | |
272 | mutex_unlock(&dmirror->mutex); | |
273 | continue; | |
274 | } | |
275 | break; | |
276 | } | |
277 | ||
278 | ret = dmirror_do_fault(dmirror, range); | |
279 | ||
280 | mutex_unlock(&dmirror->mutex); | |
281 | out: | |
282 | return ret; | |
283 | } | |
284 | ||
285 | static int dmirror_fault(struct dmirror *dmirror, unsigned long start, | |
286 | unsigned long end, bool write) | |
287 | { | |
288 | struct mm_struct *mm = dmirror->notifier.mm; | |
289 | unsigned long addr; | |
290 | unsigned long pfns[64]; | |
291 | struct hmm_range range = { | |
292 | .notifier = &dmirror->notifier, | |
293 | .hmm_pfns = pfns, | |
294 | .pfn_flags_mask = 0, | |
295 | .default_flags = | |
296 | HMM_PFN_REQ_FAULT | (write ? HMM_PFN_REQ_WRITE : 0), | |
297 | .dev_private_owner = dmirror->mdevice, | |
298 | }; | |
299 | int ret = 0; | |
300 | ||
301 | /* Since the mm is for the mirrored process, get a reference first. */ | |
302 | if (!mmget_not_zero(mm)) | |
303 | return 0; | |
304 | ||
305 | for (addr = start; addr < end; addr = range.end) { | |
306 | range.start = addr; | |
307 | range.end = min(addr + (ARRAY_SIZE(pfns) << PAGE_SHIFT), end); | |
308 | ||
309 | ret = dmirror_range_fault(dmirror, &range); | |
310 | if (ret) | |
311 | break; | |
312 | } | |
313 | ||
314 | mmput(mm); | |
315 | return ret; | |
316 | } | |
317 | ||
318 | static int dmirror_do_read(struct dmirror *dmirror, unsigned long start, | |
319 | unsigned long end, struct dmirror_bounce *bounce) | |
320 | { | |
321 | unsigned long pfn; | |
322 | void *ptr; | |
323 | ||
324 | ptr = bounce->ptr + ((start - bounce->addr) & PAGE_MASK); | |
325 | ||
326 | for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) { | |
327 | void *entry; | |
328 | struct page *page; | |
329 | void *tmp; | |
330 | ||
331 | entry = xa_load(&dmirror->pt, pfn); | |
332 | page = xa_untag_pointer(entry); | |
333 | if (!page) | |
334 | return -ENOENT; | |
335 | ||
336 | tmp = kmap(page); | |
337 | memcpy(ptr, tmp, PAGE_SIZE); | |
338 | kunmap(page); | |
339 | ||
340 | ptr += PAGE_SIZE; | |
341 | bounce->cpages++; | |
342 | } | |
343 | ||
344 | return 0; | |
345 | } | |
346 | ||
347 | static int dmirror_read(struct dmirror *dmirror, struct hmm_dmirror_cmd *cmd) | |
348 | { | |
349 | struct dmirror_bounce bounce; | |
350 | unsigned long start, end; | |
351 | unsigned long size = cmd->npages << PAGE_SHIFT; | |
352 | int ret; | |
353 | ||
354 | start = cmd->addr; | |
355 | end = start + size; | |
356 | if (end < start) | |
357 | return -EINVAL; | |
358 | ||
359 | ret = dmirror_bounce_init(&bounce, start, size); | |
360 | if (ret) | |
361 | return ret; | |
362 | ||
363 | while (1) { | |
364 | mutex_lock(&dmirror->mutex); | |
365 | ret = dmirror_do_read(dmirror, start, end, &bounce); | |
366 | mutex_unlock(&dmirror->mutex); | |
367 | if (ret != -ENOENT) | |
368 | break; | |
369 | ||
370 | start = cmd->addr + (bounce.cpages << PAGE_SHIFT); | |
371 | ret = dmirror_fault(dmirror, start, end, false); | |
372 | if (ret) | |
373 | break; | |
374 | cmd->faults++; | |
375 | } | |
376 | ||
377 | if (ret == 0) { | |
378 | if (copy_to_user(u64_to_user_ptr(cmd->ptr), bounce.ptr, | |
379 | bounce.size)) | |
380 | ret = -EFAULT; | |
381 | } | |
382 | cmd->cpages = bounce.cpages; | |
383 | dmirror_bounce_fini(&bounce); | |
384 | return ret; | |
385 | } | |
386 | ||
387 | static int dmirror_do_write(struct dmirror *dmirror, unsigned long start, | |
388 | unsigned long end, struct dmirror_bounce *bounce) | |
389 | { | |
390 | unsigned long pfn; | |
391 | void *ptr; | |
392 | ||
393 | ptr = bounce->ptr + ((start - bounce->addr) & PAGE_MASK); | |
394 | ||
395 | for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) { | |
396 | void *entry; | |
397 | struct page *page; | |
398 | void *tmp; | |
399 | ||
400 | entry = xa_load(&dmirror->pt, pfn); | |
401 | page = xa_untag_pointer(entry); | |
402 | if (!page || xa_pointer_tag(entry) != DPT_XA_TAG_WRITE) | |
403 | return -ENOENT; | |
404 | ||
405 | tmp = kmap(page); | |
406 | memcpy(tmp, ptr, PAGE_SIZE); | |
407 | kunmap(page); | |
408 | ||
409 | ptr += PAGE_SIZE; | |
410 | bounce->cpages++; | |
411 | } | |
412 | ||
413 | return 0; | |
414 | } | |
415 | ||
416 | static int dmirror_write(struct dmirror *dmirror, struct hmm_dmirror_cmd *cmd) | |
417 | { | |
418 | struct dmirror_bounce bounce; | |
419 | unsigned long start, end; | |
420 | unsigned long size = cmd->npages << PAGE_SHIFT; | |
421 | int ret; | |
422 | ||
423 | start = cmd->addr; | |
424 | end = start + size; | |
425 | if (end < start) | |
426 | return -EINVAL; | |
427 | ||
428 | ret = dmirror_bounce_init(&bounce, start, size); | |
429 | if (ret) | |
430 | return ret; | |
431 | if (copy_from_user(bounce.ptr, u64_to_user_ptr(cmd->ptr), | |
432 | bounce.size)) { | |
433 | ret = -EFAULT; | |
434 | goto fini; | |
435 | } | |
436 | ||
437 | while (1) { | |
438 | mutex_lock(&dmirror->mutex); | |
439 | ret = dmirror_do_write(dmirror, start, end, &bounce); | |
440 | mutex_unlock(&dmirror->mutex); | |
441 | if (ret != -ENOENT) | |
442 | break; | |
443 | ||
444 | start = cmd->addr + (bounce.cpages << PAGE_SHIFT); | |
445 | ret = dmirror_fault(dmirror, start, end, true); | |
446 | if (ret) | |
447 | break; | |
448 | cmd->faults++; | |
449 | } | |
450 | ||
451 | fini: | |
452 | cmd->cpages = bounce.cpages; | |
453 | dmirror_bounce_fini(&bounce); | |
454 | return ret; | |
455 | } | |
456 | ||
457 | static bool dmirror_allocate_chunk(struct dmirror_device *mdevice, | |
458 | struct page **ppage) | |
459 | { | |
460 | struct dmirror_chunk *devmem; | |
461 | struct resource *res; | |
462 | unsigned long pfn; | |
463 | unsigned long pfn_first; | |
464 | unsigned long pfn_last; | |
465 | void *ptr; | |
466 | ||
a4574f63 DW |
467 | devmem = kzalloc(sizeof(*devmem), GFP_KERNEL); |
468 | if (!devmem) | |
f3c9d0a3 | 469 | return false; |
a4574f63 DW |
470 | |
471 | res = request_free_mem_region(&iomem_resource, DEVMEM_CHUNK_SIZE, | |
472 | "hmm_dmirror"); | |
473 | if (IS_ERR(res)) | |
474 | goto err_devmem; | |
475 | ||
476 | devmem->pagemap.type = MEMORY_DEVICE_PRIVATE; | |
477 | devmem->pagemap.range.start = res->start; | |
478 | devmem->pagemap.range.end = res->end; | |
b7b3c01b | 479 | devmem->pagemap.nr_range = 1; |
a4574f63 DW |
480 | devmem->pagemap.ops = &dmirror_devmem_ops; |
481 | devmem->pagemap.owner = mdevice; | |
482 | ||
b2ef9f5a RC |
483 | mutex_lock(&mdevice->devmem_lock); |
484 | ||
485 | if (mdevice->devmem_count == mdevice->devmem_capacity) { | |
486 | struct dmirror_chunk **new_chunks; | |
487 | unsigned int new_capacity; | |
488 | ||
489 | new_capacity = mdevice->devmem_capacity + | |
490 | DEVMEM_CHUNKS_RESERVE; | |
491 | new_chunks = krealloc(mdevice->devmem_chunks, | |
492 | sizeof(new_chunks[0]) * new_capacity, | |
493 | GFP_KERNEL); | |
494 | if (!new_chunks) | |
a4574f63 | 495 | goto err_release; |
b2ef9f5a RC |
496 | mdevice->devmem_capacity = new_capacity; |
497 | mdevice->devmem_chunks = new_chunks; | |
498 | } | |
499 | ||
b2ef9f5a RC |
500 | ptr = memremap_pages(&devmem->pagemap, numa_node_id()); |
501 | if (IS_ERR(ptr)) | |
a4574f63 | 502 | goto err_release; |
b2ef9f5a RC |
503 | |
504 | devmem->mdevice = mdevice; | |
a4574f63 DW |
505 | pfn_first = devmem->pagemap.range.start >> PAGE_SHIFT; |
506 | pfn_last = pfn_first + (range_len(&devmem->pagemap.range) >> PAGE_SHIFT); | |
b2ef9f5a RC |
507 | mdevice->devmem_chunks[mdevice->devmem_count++] = devmem; |
508 | ||
509 | mutex_unlock(&mdevice->devmem_lock); | |
510 | ||
511 | pr_info("added new %u MB chunk (total %u chunks, %u MB) PFNs [0x%lx 0x%lx)\n", | |
512 | DEVMEM_CHUNK_SIZE / (1024 * 1024), | |
513 | mdevice->devmem_count, | |
514 | mdevice->devmem_count * (DEVMEM_CHUNK_SIZE / (1024 * 1024)), | |
515 | pfn_first, pfn_last); | |
516 | ||
517 | spin_lock(&mdevice->lock); | |
518 | for (pfn = pfn_first; pfn < pfn_last; pfn++) { | |
519 | struct page *page = pfn_to_page(pfn); | |
520 | ||
521 | page->zone_device_data = mdevice->free_pages; | |
522 | mdevice->free_pages = page; | |
523 | } | |
524 | if (ppage) { | |
525 | *ppage = mdevice->free_pages; | |
526 | mdevice->free_pages = (*ppage)->zone_device_data; | |
527 | mdevice->calloc++; | |
528 | } | |
529 | spin_unlock(&mdevice->lock); | |
530 | ||
531 | return true; | |
532 | ||
b2ef9f5a | 533 | err_release: |
b2ef9f5a | 534 | mutex_unlock(&mdevice->devmem_lock); |
a4574f63 DW |
535 | release_mem_region(devmem->pagemap.range.start, range_len(&devmem->pagemap.range)); |
536 | err_devmem: | |
537 | kfree(devmem); | |
538 | ||
b2ef9f5a RC |
539 | return false; |
540 | } | |
541 | ||
542 | static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice) | |
543 | { | |
544 | struct page *dpage = NULL; | |
545 | struct page *rpage; | |
546 | ||
547 | /* | |
548 | * This is a fake device so we alloc real system memory to store | |
549 | * our device memory. | |
550 | */ | |
551 | rpage = alloc_page(GFP_HIGHUSER); | |
552 | if (!rpage) | |
553 | return NULL; | |
554 | ||
555 | spin_lock(&mdevice->lock); | |
556 | ||
557 | if (mdevice->free_pages) { | |
558 | dpage = mdevice->free_pages; | |
559 | mdevice->free_pages = dpage->zone_device_data; | |
560 | mdevice->calloc++; | |
561 | spin_unlock(&mdevice->lock); | |
562 | } else { | |
563 | spin_unlock(&mdevice->lock); | |
564 | if (!dmirror_allocate_chunk(mdevice, &dpage)) | |
565 | goto error; | |
566 | } | |
567 | ||
568 | dpage->zone_device_data = rpage; | |
b2ef9f5a RC |
569 | lock_page(dpage); |
570 | return dpage; | |
571 | ||
572 | error: | |
573 | __free_page(rpage); | |
574 | return NULL; | |
575 | } | |
576 | ||
577 | static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args, | |
578 | struct dmirror *dmirror) | |
579 | { | |
580 | struct dmirror_device *mdevice = dmirror->mdevice; | |
581 | const unsigned long *src = args->src; | |
582 | unsigned long *dst = args->dst; | |
583 | unsigned long addr; | |
584 | ||
585 | for (addr = args->start; addr < args->end; addr += PAGE_SIZE, | |
586 | src++, dst++) { | |
587 | struct page *spage; | |
588 | struct page *dpage; | |
589 | struct page *rpage; | |
590 | ||
591 | if (!(*src & MIGRATE_PFN_MIGRATE)) | |
592 | continue; | |
593 | ||
594 | /* | |
595 | * Note that spage might be NULL which is OK since it is an | |
596 | * unallocated pte_none() or read-only zero page. | |
597 | */ | |
598 | spage = migrate_pfn_to_page(*src); | |
599 | ||
b2ef9f5a RC |
600 | dpage = dmirror_devmem_alloc_page(mdevice); |
601 | if (!dpage) | |
602 | continue; | |
603 | ||
604 | rpage = dpage->zone_device_data; | |
605 | if (spage) | |
606 | copy_highpage(rpage, spage); | |
607 | else | |
608 | clear_highpage(rpage); | |
609 | ||
610 | /* | |
611 | * Normally, a device would use the page->zone_device_data to | |
612 | * point to the mirror but here we use it to hold the page for | |
613 | * the simulated device memory and that page holds the pointer | |
614 | * to the mirror. | |
615 | */ | |
616 | rpage->zone_device_data = dmirror; | |
617 | ||
ab09243a | 618 | *dst = migrate_pfn(page_to_pfn(dpage)); |
b2ef9f5a RC |
619 | if ((*src & MIGRATE_PFN_WRITE) || |
620 | (!spage && args->vma->vm_flags & VM_WRITE)) | |
621 | *dst |= MIGRATE_PFN_WRITE; | |
622 | } | |
623 | } | |
624 | ||
b659baea AP |
625 | static int dmirror_check_atomic(struct dmirror *dmirror, unsigned long start, |
626 | unsigned long end) | |
627 | { | |
628 | unsigned long pfn; | |
629 | ||
630 | for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) { | |
631 | void *entry; | |
b659baea AP |
632 | |
633 | entry = xa_load(&dmirror->pt, pfn); | |
b659baea AP |
634 | if (xa_pointer_tag(entry) == DPT_XA_TAG_ATOMIC) |
635 | return -EPERM; | |
636 | } | |
637 | ||
638 | return 0; | |
639 | } | |
640 | ||
641 | static int dmirror_atomic_map(unsigned long start, unsigned long end, | |
642 | struct page **pages, struct dmirror *dmirror) | |
643 | { | |
644 | unsigned long pfn, mapped = 0; | |
645 | int i; | |
646 | ||
647 | /* Map the migrated pages into the device's page tables. */ | |
648 | mutex_lock(&dmirror->mutex); | |
649 | ||
650 | for (i = 0, pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++, i++) { | |
651 | void *entry; | |
652 | ||
653 | if (!pages[i]) | |
654 | continue; | |
655 | ||
656 | entry = pages[i]; | |
657 | entry = xa_tag_pointer(entry, DPT_XA_TAG_ATOMIC); | |
658 | entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC); | |
659 | if (xa_is_err(entry)) { | |
660 | mutex_unlock(&dmirror->mutex); | |
661 | return xa_err(entry); | |
662 | } | |
663 | ||
664 | mapped++; | |
665 | } | |
666 | ||
667 | mutex_unlock(&dmirror->mutex); | |
668 | return mapped; | |
669 | } | |
670 | ||
b2ef9f5a RC |
671 | static int dmirror_migrate_finalize_and_map(struct migrate_vma *args, |
672 | struct dmirror *dmirror) | |
673 | { | |
674 | unsigned long start = args->start; | |
675 | unsigned long end = args->end; | |
676 | const unsigned long *src = args->src; | |
677 | const unsigned long *dst = args->dst; | |
678 | unsigned long pfn; | |
679 | ||
680 | /* Map the migrated pages into the device's page tables. */ | |
681 | mutex_lock(&dmirror->mutex); | |
682 | ||
683 | for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++, | |
684 | src++, dst++) { | |
685 | struct page *dpage; | |
686 | void *entry; | |
687 | ||
688 | if (!(*src & MIGRATE_PFN_MIGRATE)) | |
689 | continue; | |
690 | ||
691 | dpage = migrate_pfn_to_page(*dst); | |
692 | if (!dpage) | |
693 | continue; | |
694 | ||
695 | /* | |
696 | * Store the page that holds the data so the page table | |
697 | * doesn't have to deal with ZONE_DEVICE private pages. | |
698 | */ | |
699 | entry = dpage->zone_device_data; | |
700 | if (*dst & MIGRATE_PFN_WRITE) | |
701 | entry = xa_tag_pointer(entry, DPT_XA_TAG_WRITE); | |
702 | entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC); | |
703 | if (xa_is_err(entry)) { | |
704 | mutex_unlock(&dmirror->mutex); | |
705 | return xa_err(entry); | |
706 | } | |
707 | } | |
708 | ||
709 | mutex_unlock(&dmirror->mutex); | |
710 | return 0; | |
711 | } | |
712 | ||
b659baea AP |
713 | static int dmirror_exclusive(struct dmirror *dmirror, |
714 | struct hmm_dmirror_cmd *cmd) | |
715 | { | |
716 | unsigned long start, end, addr; | |
717 | unsigned long size = cmd->npages << PAGE_SHIFT; | |
718 | struct mm_struct *mm = dmirror->notifier.mm; | |
719 | struct page *pages[64]; | |
720 | struct dmirror_bounce bounce; | |
721 | unsigned long next; | |
722 | int ret; | |
723 | ||
724 | start = cmd->addr; | |
725 | end = start + size; | |
726 | if (end < start) | |
727 | return -EINVAL; | |
728 | ||
729 | /* Since the mm is for the mirrored process, get a reference first. */ | |
730 | if (!mmget_not_zero(mm)) | |
731 | return -EINVAL; | |
732 | ||
733 | mmap_read_lock(mm); | |
734 | for (addr = start; addr < end; addr = next) { | |
735 | unsigned long mapped; | |
736 | int i; | |
737 | ||
738 | if (end < addr + (ARRAY_SIZE(pages) << PAGE_SHIFT)) | |
739 | next = end; | |
740 | else | |
741 | next = addr + (ARRAY_SIZE(pages) << PAGE_SHIFT); | |
742 | ||
743 | ret = make_device_exclusive_range(mm, addr, next, pages, NULL); | |
744 | mapped = dmirror_atomic_map(addr, next, pages, dmirror); | |
745 | for (i = 0; i < ret; i++) { | |
746 | if (pages[i]) { | |
747 | unlock_page(pages[i]); | |
748 | put_page(pages[i]); | |
749 | } | |
750 | } | |
751 | ||
752 | if (addr + (mapped << PAGE_SHIFT) < next) { | |
753 | mmap_read_unlock(mm); | |
754 | mmput(mm); | |
755 | return -EBUSY; | |
756 | } | |
757 | } | |
758 | mmap_read_unlock(mm); | |
759 | mmput(mm); | |
760 | ||
761 | /* Return the migrated data for verification. */ | |
762 | ret = dmirror_bounce_init(&bounce, start, size); | |
763 | if (ret) | |
764 | return ret; | |
765 | mutex_lock(&dmirror->mutex); | |
766 | ret = dmirror_do_read(dmirror, start, end, &bounce); | |
767 | mutex_unlock(&dmirror->mutex); | |
768 | if (ret == 0) { | |
769 | if (copy_to_user(u64_to_user_ptr(cmd->ptr), bounce.ptr, | |
770 | bounce.size)) | |
771 | ret = -EFAULT; | |
772 | } | |
773 | ||
774 | cmd->cpages = bounce.cpages; | |
775 | dmirror_bounce_fini(&bounce); | |
776 | return ret; | |
777 | } | |
778 | ||
b2ef9f5a RC |
779 | static int dmirror_migrate(struct dmirror *dmirror, |
780 | struct hmm_dmirror_cmd *cmd) | |
781 | { | |
782 | unsigned long start, end, addr; | |
783 | unsigned long size = cmd->npages << PAGE_SHIFT; | |
784 | struct mm_struct *mm = dmirror->notifier.mm; | |
785 | struct vm_area_struct *vma; | |
786 | unsigned long src_pfns[64]; | |
787 | unsigned long dst_pfns[64]; | |
788 | struct dmirror_bounce bounce; | |
789 | struct migrate_vma args; | |
790 | unsigned long next; | |
791 | int ret; | |
792 | ||
793 | start = cmd->addr; | |
794 | end = start + size; | |
795 | if (end < start) | |
796 | return -EINVAL; | |
797 | ||
798 | /* Since the mm is for the mirrored process, get a reference first. */ | |
799 | if (!mmget_not_zero(mm)) | |
800 | return -EINVAL; | |
801 | ||
89154dd5 | 802 | mmap_read_lock(mm); |
b2ef9f5a | 803 | for (addr = start; addr < end; addr = next) { |
46e6b31d LH |
804 | vma = vma_lookup(mm, addr); |
805 | if (!vma || !(vma->vm_flags & VM_READ)) { | |
b2ef9f5a RC |
806 | ret = -EINVAL; |
807 | goto out; | |
808 | } | |
809 | next = min(end, addr + (ARRAY_SIZE(src_pfns) << PAGE_SHIFT)); | |
810 | if (next > vma->vm_end) | |
811 | next = vma->vm_end; | |
812 | ||
813 | args.vma = vma; | |
814 | args.src = src_pfns; | |
815 | args.dst = dst_pfns; | |
816 | args.start = addr; | |
817 | args.end = next; | |
7d17e83a | 818 | args.pgmap_owner = dmirror->mdevice; |
5143192c | 819 | args.flags = MIGRATE_VMA_SELECT_SYSTEM; |
b2ef9f5a RC |
820 | ret = migrate_vma_setup(&args); |
821 | if (ret) | |
822 | goto out; | |
823 | ||
824 | dmirror_migrate_alloc_and_copy(&args, dmirror); | |
825 | migrate_vma_pages(&args); | |
826 | dmirror_migrate_finalize_and_map(&args, dmirror); | |
827 | migrate_vma_finalize(&args); | |
828 | } | |
89154dd5 | 829 | mmap_read_unlock(mm); |
b2ef9f5a RC |
830 | mmput(mm); |
831 | ||
832 | /* Return the migrated data for verification. */ | |
833 | ret = dmirror_bounce_init(&bounce, start, size); | |
834 | if (ret) | |
835 | return ret; | |
836 | mutex_lock(&dmirror->mutex); | |
837 | ret = dmirror_do_read(dmirror, start, end, &bounce); | |
838 | mutex_unlock(&dmirror->mutex); | |
839 | if (ret == 0) { | |
840 | if (copy_to_user(u64_to_user_ptr(cmd->ptr), bounce.ptr, | |
841 | bounce.size)) | |
842 | ret = -EFAULT; | |
843 | } | |
844 | cmd->cpages = bounce.cpages; | |
845 | dmirror_bounce_fini(&bounce); | |
846 | return ret; | |
847 | ||
848 | out: | |
89154dd5 | 849 | mmap_read_unlock(mm); |
b2ef9f5a RC |
850 | mmput(mm); |
851 | return ret; | |
852 | } | |
853 | ||
854 | static void dmirror_mkentry(struct dmirror *dmirror, struct hmm_range *range, | |
855 | unsigned char *perm, unsigned long entry) | |
856 | { | |
857 | struct page *page; | |
858 | ||
859 | if (entry & HMM_PFN_ERROR) { | |
860 | *perm = HMM_DMIRROR_PROT_ERROR; | |
861 | return; | |
862 | } | |
863 | if (!(entry & HMM_PFN_VALID)) { | |
864 | *perm = HMM_DMIRROR_PROT_NONE; | |
865 | return; | |
866 | } | |
867 | ||
868 | page = hmm_pfn_to_page(entry); | |
869 | if (is_device_private_page(page)) { | |
870 | /* Is the page migrated to this device or some other? */ | |
871 | if (dmirror->mdevice == dmirror_page_to_device(page)) | |
872 | *perm = HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL; | |
873 | else | |
874 | *perm = HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE; | |
875 | } else if (is_zero_pfn(page_to_pfn(page))) | |
876 | *perm = HMM_DMIRROR_PROT_ZERO; | |
877 | else | |
878 | *perm = HMM_DMIRROR_PROT_NONE; | |
879 | if (entry & HMM_PFN_WRITE) | |
880 | *perm |= HMM_DMIRROR_PROT_WRITE; | |
881 | else | |
882 | *perm |= HMM_DMIRROR_PROT_READ; | |
e478425b RC |
883 | if (hmm_pfn_to_map_order(entry) + PAGE_SHIFT == PMD_SHIFT) |
884 | *perm |= HMM_DMIRROR_PROT_PMD; | |
885 | else if (hmm_pfn_to_map_order(entry) + PAGE_SHIFT == PUD_SHIFT) | |
886 | *perm |= HMM_DMIRROR_PROT_PUD; | |
b2ef9f5a RC |
887 | } |
888 | ||
889 | static bool dmirror_snapshot_invalidate(struct mmu_interval_notifier *mni, | |
890 | const struct mmu_notifier_range *range, | |
891 | unsigned long cur_seq) | |
892 | { | |
893 | struct dmirror_interval *dmi = | |
894 | container_of(mni, struct dmirror_interval, notifier); | |
895 | struct dmirror *dmirror = dmi->dmirror; | |
896 | ||
897 | if (mmu_notifier_range_blockable(range)) | |
898 | mutex_lock(&dmirror->mutex); | |
899 | else if (!mutex_trylock(&dmirror->mutex)) | |
900 | return false; | |
901 | ||
902 | /* | |
903 | * Snapshots only need to set the sequence number since any | |
904 | * invalidation in the interval invalidates the whole snapshot. | |
905 | */ | |
906 | mmu_interval_set_seq(mni, cur_seq); | |
907 | ||
908 | mutex_unlock(&dmirror->mutex); | |
909 | return true; | |
910 | } | |
911 | ||
912 | static const struct mmu_interval_notifier_ops dmirror_mrn_ops = { | |
913 | .invalidate = dmirror_snapshot_invalidate, | |
914 | }; | |
915 | ||
916 | static int dmirror_range_snapshot(struct dmirror *dmirror, | |
917 | struct hmm_range *range, | |
918 | unsigned char *perm) | |
919 | { | |
920 | struct mm_struct *mm = dmirror->notifier.mm; | |
921 | struct dmirror_interval notifier; | |
922 | unsigned long timeout = | |
923 | jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT); | |
924 | unsigned long i; | |
925 | unsigned long n; | |
926 | int ret = 0; | |
927 | ||
928 | notifier.dmirror = dmirror; | |
929 | range->notifier = ¬ifier.notifier; | |
930 | ||
931 | ret = mmu_interval_notifier_insert(range->notifier, mm, | |
932 | range->start, range->end - range->start, | |
933 | &dmirror_mrn_ops); | |
934 | if (ret) | |
935 | return ret; | |
936 | ||
937 | while (true) { | |
938 | if (time_after(jiffies, timeout)) { | |
939 | ret = -EBUSY; | |
940 | goto out; | |
941 | } | |
942 | ||
943 | range->notifier_seq = mmu_interval_read_begin(range->notifier); | |
944 | ||
89154dd5 | 945 | mmap_read_lock(mm); |
b2ef9f5a | 946 | ret = hmm_range_fault(range); |
89154dd5 | 947 | mmap_read_unlock(mm); |
b2ef9f5a RC |
948 | if (ret) { |
949 | if (ret == -EBUSY) | |
950 | continue; | |
951 | goto out; | |
952 | } | |
953 | ||
954 | mutex_lock(&dmirror->mutex); | |
955 | if (mmu_interval_read_retry(range->notifier, | |
956 | range->notifier_seq)) { | |
957 | mutex_unlock(&dmirror->mutex); | |
958 | continue; | |
959 | } | |
960 | break; | |
961 | } | |
962 | ||
963 | n = (range->end - range->start) >> PAGE_SHIFT; | |
964 | for (i = 0; i < n; i++) | |
965 | dmirror_mkentry(dmirror, range, perm + i, range->hmm_pfns[i]); | |
966 | ||
967 | mutex_unlock(&dmirror->mutex); | |
968 | out: | |
969 | mmu_interval_notifier_remove(range->notifier); | |
970 | return ret; | |
971 | } | |
972 | ||
973 | static int dmirror_snapshot(struct dmirror *dmirror, | |
974 | struct hmm_dmirror_cmd *cmd) | |
975 | { | |
976 | struct mm_struct *mm = dmirror->notifier.mm; | |
977 | unsigned long start, end; | |
978 | unsigned long size = cmd->npages << PAGE_SHIFT; | |
979 | unsigned long addr; | |
980 | unsigned long next; | |
981 | unsigned long pfns[64]; | |
982 | unsigned char perm[64]; | |
983 | char __user *uptr; | |
984 | struct hmm_range range = { | |
985 | .hmm_pfns = pfns, | |
986 | .dev_private_owner = dmirror->mdevice, | |
987 | }; | |
988 | int ret = 0; | |
989 | ||
990 | start = cmd->addr; | |
991 | end = start + size; | |
992 | if (end < start) | |
993 | return -EINVAL; | |
994 | ||
995 | /* Since the mm is for the mirrored process, get a reference first. */ | |
996 | if (!mmget_not_zero(mm)) | |
997 | return -EINVAL; | |
998 | ||
999 | /* | |
1000 | * Register a temporary notifier to detect invalidations even if it | |
1001 | * overlaps with other mmu_interval_notifiers. | |
1002 | */ | |
1003 | uptr = u64_to_user_ptr(cmd->ptr); | |
1004 | for (addr = start; addr < end; addr = next) { | |
1005 | unsigned long n; | |
1006 | ||
1007 | next = min(addr + (ARRAY_SIZE(pfns) << PAGE_SHIFT), end); | |
1008 | range.start = addr; | |
1009 | range.end = next; | |
1010 | ||
1011 | ret = dmirror_range_snapshot(dmirror, &range, perm); | |
1012 | if (ret) | |
1013 | break; | |
1014 | ||
1015 | n = (range.end - range.start) >> PAGE_SHIFT; | |
1016 | if (copy_to_user(uptr, perm, n)) { | |
1017 | ret = -EFAULT; | |
1018 | break; | |
1019 | } | |
1020 | ||
1021 | cmd->cpages += n; | |
1022 | uptr += n; | |
1023 | } | |
1024 | mmput(mm); | |
1025 | ||
1026 | return ret; | |
1027 | } | |
1028 | ||
1029 | static long dmirror_fops_unlocked_ioctl(struct file *filp, | |
1030 | unsigned int command, | |
1031 | unsigned long arg) | |
1032 | { | |
1033 | void __user *uarg = (void __user *)arg; | |
1034 | struct hmm_dmirror_cmd cmd; | |
1035 | struct dmirror *dmirror; | |
1036 | int ret; | |
1037 | ||
1038 | dmirror = filp->private_data; | |
1039 | if (!dmirror) | |
1040 | return -EINVAL; | |
1041 | ||
1042 | if (copy_from_user(&cmd, uarg, sizeof(cmd))) | |
1043 | return -EFAULT; | |
1044 | ||
1045 | if (cmd.addr & ~PAGE_MASK) | |
1046 | return -EINVAL; | |
1047 | if (cmd.addr >= (cmd.addr + (cmd.npages << PAGE_SHIFT))) | |
1048 | return -EINVAL; | |
1049 | ||
1050 | cmd.cpages = 0; | |
1051 | cmd.faults = 0; | |
1052 | ||
1053 | switch (command) { | |
1054 | case HMM_DMIRROR_READ: | |
1055 | ret = dmirror_read(dmirror, &cmd); | |
1056 | break; | |
1057 | ||
1058 | case HMM_DMIRROR_WRITE: | |
1059 | ret = dmirror_write(dmirror, &cmd); | |
1060 | break; | |
1061 | ||
1062 | case HMM_DMIRROR_MIGRATE: | |
1063 | ret = dmirror_migrate(dmirror, &cmd); | |
1064 | break; | |
1065 | ||
b659baea AP |
1066 | case HMM_DMIRROR_EXCLUSIVE: |
1067 | ret = dmirror_exclusive(dmirror, &cmd); | |
1068 | break; | |
1069 | ||
1070 | case HMM_DMIRROR_CHECK_EXCLUSIVE: | |
1071 | ret = dmirror_check_atomic(dmirror, cmd.addr, | |
1072 | cmd.addr + (cmd.npages << PAGE_SHIFT)); | |
1073 | break; | |
1074 | ||
b2ef9f5a RC |
1075 | case HMM_DMIRROR_SNAPSHOT: |
1076 | ret = dmirror_snapshot(dmirror, &cmd); | |
1077 | break; | |
1078 | ||
1079 | default: | |
1080 | return -EINVAL; | |
1081 | } | |
1082 | if (ret) | |
1083 | return ret; | |
1084 | ||
1085 | if (copy_to_user(uarg, &cmd, sizeof(cmd))) | |
1086 | return -EFAULT; | |
1087 | ||
1088 | return 0; | |
1089 | } | |
1090 | ||
87c01d57 AP |
1091 | static int dmirror_fops_mmap(struct file *file, struct vm_area_struct *vma) |
1092 | { | |
1093 | unsigned long addr; | |
1094 | ||
1095 | for (addr = vma->vm_start; addr < vma->vm_end; addr += PAGE_SIZE) { | |
1096 | struct page *page; | |
1097 | int ret; | |
1098 | ||
1099 | page = alloc_page(GFP_KERNEL | __GFP_ZERO); | |
1100 | if (!page) | |
1101 | return -ENOMEM; | |
1102 | ||
1103 | ret = vm_insert_page(vma, addr, page); | |
1104 | if (ret) { | |
1105 | __free_page(page); | |
1106 | return ret; | |
1107 | } | |
1108 | put_page(page); | |
1109 | } | |
1110 | ||
1111 | return 0; | |
1112 | } | |
1113 | ||
b2ef9f5a RC |
1114 | static const struct file_operations dmirror_fops = { |
1115 | .open = dmirror_fops_open, | |
1116 | .release = dmirror_fops_release, | |
87c01d57 | 1117 | .mmap = dmirror_fops_mmap, |
b2ef9f5a RC |
1118 | .unlocked_ioctl = dmirror_fops_unlocked_ioctl, |
1119 | .llseek = default_llseek, | |
1120 | .owner = THIS_MODULE, | |
1121 | }; | |
1122 | ||
1123 | static void dmirror_devmem_free(struct page *page) | |
1124 | { | |
1125 | struct page *rpage = page->zone_device_data; | |
1126 | struct dmirror_device *mdevice; | |
1127 | ||
1128 | if (rpage) | |
1129 | __free_page(rpage); | |
1130 | ||
1131 | mdevice = dmirror_page_to_device(page); | |
1132 | ||
1133 | spin_lock(&mdevice->lock); | |
1134 | mdevice->cfree++; | |
1135 | page->zone_device_data = mdevice->free_pages; | |
1136 | mdevice->free_pages = page; | |
1137 | spin_unlock(&mdevice->lock); | |
1138 | } | |
1139 | ||
1140 | static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args, | |
7d17e83a | 1141 | struct dmirror *dmirror) |
b2ef9f5a RC |
1142 | { |
1143 | const unsigned long *src = args->src; | |
1144 | unsigned long *dst = args->dst; | |
1145 | unsigned long start = args->start; | |
1146 | unsigned long end = args->end; | |
1147 | unsigned long addr; | |
1148 | ||
1149 | for (addr = start; addr < end; addr += PAGE_SIZE, | |
1150 | src++, dst++) { | |
1151 | struct page *dpage, *spage; | |
1152 | ||
1153 | spage = migrate_pfn_to_page(*src); | |
1154 | if (!spage || !(*src & MIGRATE_PFN_MIGRATE)) | |
1155 | continue; | |
1156 | spage = spage->zone_device_data; | |
1157 | ||
1158 | dpage = alloc_page_vma(GFP_HIGHUSER_MOVABLE, args->vma, addr); | |
1159 | if (!dpage) | |
1160 | continue; | |
1161 | ||
1162 | lock_page(dpage); | |
7d17e83a | 1163 | xa_erase(&dmirror->pt, addr >> PAGE_SHIFT); |
b2ef9f5a | 1164 | copy_highpage(dpage, spage); |
ab09243a | 1165 | *dst = migrate_pfn(page_to_pfn(dpage)); |
b2ef9f5a RC |
1166 | if (*src & MIGRATE_PFN_WRITE) |
1167 | *dst |= MIGRATE_PFN_WRITE; | |
1168 | } | |
1169 | return 0; | |
1170 | } | |
1171 | ||
b2ef9f5a RC |
1172 | static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf) |
1173 | { | |
1174 | struct migrate_vma args; | |
1175 | unsigned long src_pfns; | |
1176 | unsigned long dst_pfns; | |
1177 | struct page *rpage; | |
1178 | struct dmirror *dmirror; | |
1179 | vm_fault_t ret; | |
1180 | ||
1181 | /* | |
1182 | * Normally, a device would use the page->zone_device_data to point to | |
1183 | * the mirror but here we use it to hold the page for the simulated | |
1184 | * device memory and that page holds the pointer to the mirror. | |
1185 | */ | |
1186 | rpage = vmf->page->zone_device_data; | |
1187 | dmirror = rpage->zone_device_data; | |
1188 | ||
1189 | /* FIXME demonstrate how we can adjust migrate range */ | |
1190 | args.vma = vmf->vma; | |
1191 | args.start = vmf->address; | |
1192 | args.end = args.start + PAGE_SIZE; | |
1193 | args.src = &src_pfns; | |
1194 | args.dst = &dst_pfns; | |
5143192c RC |
1195 | args.pgmap_owner = dmirror->mdevice; |
1196 | args.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE; | |
b2ef9f5a RC |
1197 | |
1198 | if (migrate_vma_setup(&args)) | |
1199 | return VM_FAULT_SIGBUS; | |
1200 | ||
7d17e83a | 1201 | ret = dmirror_devmem_fault_alloc_and_copy(&args, dmirror); |
b2ef9f5a RC |
1202 | if (ret) |
1203 | return ret; | |
1204 | migrate_vma_pages(&args); | |
7d17e83a RC |
1205 | /* |
1206 | * No device finalize step is needed since | |
1207 | * dmirror_devmem_fault_alloc_and_copy() will have already | |
1208 | * invalidated the device page table. | |
1209 | */ | |
b2ef9f5a RC |
1210 | migrate_vma_finalize(&args); |
1211 | return 0; | |
1212 | } | |
1213 | ||
1214 | static const struct dev_pagemap_ops dmirror_devmem_ops = { | |
1215 | .page_free = dmirror_devmem_free, | |
1216 | .migrate_to_ram = dmirror_devmem_fault, | |
1217 | }; | |
1218 | ||
1219 | static int dmirror_device_init(struct dmirror_device *mdevice, int id) | |
1220 | { | |
1221 | dev_t dev; | |
1222 | int ret; | |
1223 | ||
1224 | dev = MKDEV(MAJOR(dmirror_dev), id); | |
1225 | mutex_init(&mdevice->devmem_lock); | |
1226 | spin_lock_init(&mdevice->lock); | |
1227 | ||
1228 | cdev_init(&mdevice->cdevice, &dmirror_fops); | |
1229 | mdevice->cdevice.owner = THIS_MODULE; | |
1230 | ret = cdev_add(&mdevice->cdevice, dev, 1); | |
1231 | if (ret) | |
1232 | return ret; | |
1233 | ||
1234 | /* Build a list of free ZONE_DEVICE private struct pages */ | |
1235 | dmirror_allocate_chunk(mdevice, NULL); | |
1236 | ||
1237 | return 0; | |
1238 | } | |
1239 | ||
1240 | static void dmirror_device_remove(struct dmirror_device *mdevice) | |
1241 | { | |
1242 | unsigned int i; | |
1243 | ||
1244 | if (mdevice->devmem_chunks) { | |
1245 | for (i = 0; i < mdevice->devmem_count; i++) { | |
1246 | struct dmirror_chunk *devmem = | |
1247 | mdevice->devmem_chunks[i]; | |
1248 | ||
1249 | memunmap_pages(&devmem->pagemap); | |
a4574f63 DW |
1250 | release_mem_region(devmem->pagemap.range.start, |
1251 | range_len(&devmem->pagemap.range)); | |
b2ef9f5a RC |
1252 | kfree(devmem); |
1253 | } | |
1254 | kfree(mdevice->devmem_chunks); | |
1255 | } | |
1256 | ||
1257 | cdev_del(&mdevice->cdevice); | |
1258 | } | |
1259 | ||
1260 | static int __init hmm_dmirror_init(void) | |
1261 | { | |
1262 | int ret; | |
1263 | int id; | |
1264 | ||
1265 | ret = alloc_chrdev_region(&dmirror_dev, 0, DMIRROR_NDEVICES, | |
1266 | "HMM_DMIRROR"); | |
1267 | if (ret) | |
1268 | goto err_unreg; | |
1269 | ||
1270 | for (id = 0; id < DMIRROR_NDEVICES; id++) { | |
1271 | ret = dmirror_device_init(dmirror_devices + id, id); | |
1272 | if (ret) | |
1273 | goto err_chrdev; | |
1274 | } | |
1275 | ||
b2ef9f5a RC |
1276 | pr_info("HMM test module loaded. This is only for testing HMM.\n"); |
1277 | return 0; | |
1278 | ||
1279 | err_chrdev: | |
1280 | while (--id >= 0) | |
1281 | dmirror_device_remove(dmirror_devices + id); | |
1282 | unregister_chrdev_region(dmirror_dev, DMIRROR_NDEVICES); | |
1283 | err_unreg: | |
1284 | return ret; | |
1285 | } | |
1286 | ||
1287 | static void __exit hmm_dmirror_exit(void) | |
1288 | { | |
1289 | int id; | |
1290 | ||
b2ef9f5a RC |
1291 | for (id = 0; id < DMIRROR_NDEVICES; id++) |
1292 | dmirror_device_remove(dmirror_devices + id); | |
1293 | unregister_chrdev_region(dmirror_dev, DMIRROR_NDEVICES); | |
1294 | } | |
1295 | ||
1296 | module_init(hmm_dmirror_init); | |
1297 | module_exit(hmm_dmirror_exit); | |
1298 | MODULE_LICENSE("GPL"); |