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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 | ||
25b80162 AS |
40 | static unsigned long spm_addr_dev0; |
41 | module_param(spm_addr_dev0, long, 0644); | |
42 | MODULE_PARM_DESC(spm_addr_dev0, | |
43 | "Specify start address for SPM (special purpose memory) used for device 0. By setting this Coherent device type will be used. Make sure spm_addr_dev1 is set too. Minimum SPM size should be DEVMEM_CHUNK_SIZE."); | |
44 | ||
45 | static unsigned long spm_addr_dev1; | |
46 | module_param(spm_addr_dev1, long, 0644); | |
47 | MODULE_PARM_DESC(spm_addr_dev1, | |
48 | "Specify start address for SPM (special purpose memory) used for device 1. By setting this Coherent device type will be used. Make sure spm_addr_dev0 is set too. Minimum SPM size should be DEVMEM_CHUNK_SIZE."); | |
49 | ||
b2ef9f5a RC |
50 | static const struct dev_pagemap_ops dmirror_devmem_ops; |
51 | static const struct mmu_interval_notifier_ops dmirror_min_ops; | |
52 | static dev_t dmirror_dev; | |
b2ef9f5a RC |
53 | |
54 | struct dmirror_device; | |
55 | ||
56 | struct dmirror_bounce { | |
57 | void *ptr; | |
58 | unsigned long size; | |
59 | unsigned long addr; | |
60 | unsigned long cpages; | |
61 | }; | |
62 | ||
b659baea | 63 | #define DPT_XA_TAG_ATOMIC 1UL |
b2ef9f5a RC |
64 | #define DPT_XA_TAG_WRITE 3UL |
65 | ||
66 | /* | |
67 | * Data structure to track address ranges and register for mmu interval | |
68 | * notifier updates. | |
69 | */ | |
70 | struct dmirror_interval { | |
71 | struct mmu_interval_notifier notifier; | |
72 | struct dmirror *dmirror; | |
73 | }; | |
74 | ||
75 | /* | |
76 | * Data attached to the open device file. | |
77 | * Note that it might be shared after a fork(). | |
78 | */ | |
79 | struct dmirror { | |
80 | struct dmirror_device *mdevice; | |
81 | struct xarray pt; | |
82 | struct mmu_interval_notifier notifier; | |
83 | struct mutex mutex; | |
84 | }; | |
85 | ||
86 | /* | |
87 | * ZONE_DEVICE pages for migration and simulating device memory. | |
88 | */ | |
89 | struct dmirror_chunk { | |
90 | struct dev_pagemap pagemap; | |
91 | struct dmirror_device *mdevice; | |
92 | }; | |
93 | ||
94 | /* | |
95 | * Per device data. | |
96 | */ | |
97 | struct dmirror_device { | |
98 | struct cdev cdevice; | |
99 | struct hmm_devmem *devmem; | |
188f4826 | 100 | unsigned int zone_device_type; |
b2ef9f5a RC |
101 | |
102 | unsigned int devmem_capacity; | |
103 | unsigned int devmem_count; | |
104 | struct dmirror_chunk **devmem_chunks; | |
105 | struct mutex devmem_lock; /* protects the above */ | |
106 | ||
107 | unsigned long calloc; | |
108 | unsigned long cfree; | |
109 | struct page *free_pages; | |
110 | spinlock_t lock; /* protects the above */ | |
111 | }; | |
112 | ||
113 | static struct dmirror_device dmirror_devices[DMIRROR_NDEVICES]; | |
114 | ||
115 | static int dmirror_bounce_init(struct dmirror_bounce *bounce, | |
116 | unsigned long addr, | |
117 | unsigned long size) | |
118 | { | |
119 | bounce->addr = addr; | |
120 | bounce->size = size; | |
121 | bounce->cpages = 0; | |
122 | bounce->ptr = vmalloc(size); | |
123 | if (!bounce->ptr) | |
124 | return -ENOMEM; | |
125 | return 0; | |
126 | } | |
127 | ||
128 | static void dmirror_bounce_fini(struct dmirror_bounce *bounce) | |
129 | { | |
130 | vfree(bounce->ptr); | |
131 | } | |
132 | ||
133 | static int dmirror_fops_open(struct inode *inode, struct file *filp) | |
134 | { | |
135 | struct cdev *cdev = inode->i_cdev; | |
136 | struct dmirror *dmirror; | |
137 | int ret; | |
138 | ||
139 | /* Mirror this process address space */ | |
140 | dmirror = kzalloc(sizeof(*dmirror), GFP_KERNEL); | |
141 | if (dmirror == NULL) | |
142 | return -ENOMEM; | |
143 | ||
144 | dmirror->mdevice = container_of(cdev, struct dmirror_device, cdevice); | |
145 | mutex_init(&dmirror->mutex); | |
146 | xa_init(&dmirror->pt); | |
147 | ||
148 | ret = mmu_interval_notifier_insert(&dmirror->notifier, current->mm, | |
149 | 0, ULONG_MAX & PAGE_MASK, &dmirror_min_ops); | |
150 | if (ret) { | |
151 | kfree(dmirror); | |
152 | return ret; | |
153 | } | |
154 | ||
155 | filp->private_data = dmirror; | |
156 | return 0; | |
157 | } | |
158 | ||
159 | static int dmirror_fops_release(struct inode *inode, struct file *filp) | |
160 | { | |
161 | struct dmirror *dmirror = filp->private_data; | |
162 | ||
163 | mmu_interval_notifier_remove(&dmirror->notifier); | |
164 | xa_destroy(&dmirror->pt); | |
165 | kfree(dmirror); | |
166 | return 0; | |
167 | } | |
168 | ||
169 | static struct dmirror_device *dmirror_page_to_device(struct page *page) | |
170 | ||
171 | { | |
172 | return container_of(page->pgmap, struct dmirror_chunk, | |
173 | pagemap)->mdevice; | |
174 | } | |
175 | ||
176 | static int dmirror_do_fault(struct dmirror *dmirror, struct hmm_range *range) | |
177 | { | |
178 | unsigned long *pfns = range->hmm_pfns; | |
179 | unsigned long pfn; | |
180 | ||
181 | for (pfn = (range->start >> PAGE_SHIFT); | |
182 | pfn < (range->end >> PAGE_SHIFT); | |
183 | pfn++, pfns++) { | |
184 | struct page *page; | |
185 | void *entry; | |
186 | ||
187 | /* | |
188 | * Since we asked for hmm_range_fault() to populate pages, | |
189 | * it shouldn't return an error entry on success. | |
190 | */ | |
191 | WARN_ON(*pfns & HMM_PFN_ERROR); | |
192 | WARN_ON(!(*pfns & HMM_PFN_VALID)); | |
193 | ||
194 | page = hmm_pfn_to_page(*pfns); | |
195 | WARN_ON(!page); | |
196 | ||
197 | entry = page; | |
198 | if (*pfns & HMM_PFN_WRITE) | |
199 | entry = xa_tag_pointer(entry, DPT_XA_TAG_WRITE); | |
200 | else if (WARN_ON(range->default_flags & HMM_PFN_WRITE)) | |
201 | return -EFAULT; | |
202 | entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC); | |
203 | if (xa_is_err(entry)) | |
204 | return xa_err(entry); | |
205 | } | |
206 | ||
207 | return 0; | |
208 | } | |
209 | ||
210 | static void dmirror_do_update(struct dmirror *dmirror, unsigned long start, | |
211 | unsigned long end) | |
212 | { | |
213 | unsigned long pfn; | |
214 | void *entry; | |
215 | ||
216 | /* | |
217 | * The XArray doesn't hold references to pages since it relies on | |
218 | * the mmu notifier to clear page pointers when they become stale. | |
219 | * Therefore, it is OK to just clear the entry. | |
220 | */ | |
221 | xa_for_each_range(&dmirror->pt, pfn, entry, start >> PAGE_SHIFT, | |
222 | end >> PAGE_SHIFT) | |
223 | xa_erase(&dmirror->pt, pfn); | |
224 | } | |
225 | ||
226 | static bool dmirror_interval_invalidate(struct mmu_interval_notifier *mni, | |
227 | const struct mmu_notifier_range *range, | |
228 | unsigned long cur_seq) | |
229 | { | |
230 | struct dmirror *dmirror = container_of(mni, struct dmirror, notifier); | |
231 | ||
7d17e83a RC |
232 | /* |
233 | * Ignore invalidation callbacks for device private pages since | |
234 | * the invalidation is handled as part of the migration process. | |
235 | */ | |
236 | if (range->event == MMU_NOTIFY_MIGRATE && | |
6b49bf6d | 237 | range->owner == dmirror->mdevice) |
7d17e83a RC |
238 | return true; |
239 | ||
b2ef9f5a RC |
240 | if (mmu_notifier_range_blockable(range)) |
241 | mutex_lock(&dmirror->mutex); | |
242 | else if (!mutex_trylock(&dmirror->mutex)) | |
243 | return false; | |
244 | ||
245 | mmu_interval_set_seq(mni, cur_seq); | |
246 | dmirror_do_update(dmirror, range->start, range->end); | |
247 | ||
248 | mutex_unlock(&dmirror->mutex); | |
249 | return true; | |
250 | } | |
251 | ||
252 | static const struct mmu_interval_notifier_ops dmirror_min_ops = { | |
253 | .invalidate = dmirror_interval_invalidate, | |
254 | }; | |
255 | ||
256 | static int dmirror_range_fault(struct dmirror *dmirror, | |
257 | struct hmm_range *range) | |
258 | { | |
259 | struct mm_struct *mm = dmirror->notifier.mm; | |
260 | unsigned long timeout = | |
261 | jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT); | |
262 | int ret; | |
263 | ||
264 | while (true) { | |
265 | if (time_after(jiffies, timeout)) { | |
266 | ret = -EBUSY; | |
267 | goto out; | |
268 | } | |
269 | ||
270 | range->notifier_seq = mmu_interval_read_begin(range->notifier); | |
89154dd5 | 271 | mmap_read_lock(mm); |
b2ef9f5a | 272 | ret = hmm_range_fault(range); |
89154dd5 | 273 | mmap_read_unlock(mm); |
b2ef9f5a RC |
274 | if (ret) { |
275 | if (ret == -EBUSY) | |
276 | continue; | |
277 | goto out; | |
278 | } | |
279 | ||
280 | mutex_lock(&dmirror->mutex); | |
281 | if (mmu_interval_read_retry(range->notifier, | |
282 | range->notifier_seq)) { | |
283 | mutex_unlock(&dmirror->mutex); | |
284 | continue; | |
285 | } | |
286 | break; | |
287 | } | |
288 | ||
289 | ret = dmirror_do_fault(dmirror, range); | |
290 | ||
291 | mutex_unlock(&dmirror->mutex); | |
292 | out: | |
293 | return ret; | |
294 | } | |
295 | ||
296 | static int dmirror_fault(struct dmirror *dmirror, unsigned long start, | |
297 | unsigned long end, bool write) | |
298 | { | |
299 | struct mm_struct *mm = dmirror->notifier.mm; | |
300 | unsigned long addr; | |
301 | unsigned long pfns[64]; | |
302 | struct hmm_range range = { | |
303 | .notifier = &dmirror->notifier, | |
304 | .hmm_pfns = pfns, | |
305 | .pfn_flags_mask = 0, | |
306 | .default_flags = | |
307 | HMM_PFN_REQ_FAULT | (write ? HMM_PFN_REQ_WRITE : 0), | |
308 | .dev_private_owner = dmirror->mdevice, | |
309 | }; | |
310 | int ret = 0; | |
311 | ||
312 | /* Since the mm is for the mirrored process, get a reference first. */ | |
313 | if (!mmget_not_zero(mm)) | |
314 | return 0; | |
315 | ||
316 | for (addr = start; addr < end; addr = range.end) { | |
317 | range.start = addr; | |
318 | range.end = min(addr + (ARRAY_SIZE(pfns) << PAGE_SHIFT), end); | |
319 | ||
320 | ret = dmirror_range_fault(dmirror, &range); | |
321 | if (ret) | |
322 | break; | |
323 | } | |
324 | ||
325 | mmput(mm); | |
326 | return ret; | |
327 | } | |
328 | ||
329 | static int dmirror_do_read(struct dmirror *dmirror, unsigned long start, | |
330 | unsigned long end, struct dmirror_bounce *bounce) | |
331 | { | |
332 | unsigned long pfn; | |
333 | void *ptr; | |
334 | ||
335 | ptr = bounce->ptr + ((start - bounce->addr) & PAGE_MASK); | |
336 | ||
337 | for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) { | |
338 | void *entry; | |
339 | struct page *page; | |
340 | void *tmp; | |
341 | ||
342 | entry = xa_load(&dmirror->pt, pfn); | |
343 | page = xa_untag_pointer(entry); | |
344 | if (!page) | |
345 | return -ENOENT; | |
346 | ||
347 | tmp = kmap(page); | |
348 | memcpy(ptr, tmp, PAGE_SIZE); | |
349 | kunmap(page); | |
350 | ||
351 | ptr += PAGE_SIZE; | |
352 | bounce->cpages++; | |
353 | } | |
354 | ||
355 | return 0; | |
356 | } | |
357 | ||
358 | static int dmirror_read(struct dmirror *dmirror, struct hmm_dmirror_cmd *cmd) | |
359 | { | |
360 | struct dmirror_bounce bounce; | |
361 | unsigned long start, end; | |
362 | unsigned long size = cmd->npages << PAGE_SHIFT; | |
363 | int ret; | |
364 | ||
365 | start = cmd->addr; | |
366 | end = start + size; | |
367 | if (end < start) | |
368 | return -EINVAL; | |
369 | ||
370 | ret = dmirror_bounce_init(&bounce, start, size); | |
371 | if (ret) | |
372 | return ret; | |
373 | ||
374 | while (1) { | |
375 | mutex_lock(&dmirror->mutex); | |
376 | ret = dmirror_do_read(dmirror, start, end, &bounce); | |
377 | mutex_unlock(&dmirror->mutex); | |
378 | if (ret != -ENOENT) | |
379 | break; | |
380 | ||
381 | start = cmd->addr + (bounce.cpages << PAGE_SHIFT); | |
382 | ret = dmirror_fault(dmirror, start, end, false); | |
383 | if (ret) | |
384 | break; | |
385 | cmd->faults++; | |
386 | } | |
387 | ||
388 | if (ret == 0) { | |
389 | if (copy_to_user(u64_to_user_ptr(cmd->ptr), bounce.ptr, | |
390 | bounce.size)) | |
391 | ret = -EFAULT; | |
392 | } | |
393 | cmd->cpages = bounce.cpages; | |
394 | dmirror_bounce_fini(&bounce); | |
395 | return ret; | |
396 | } | |
397 | ||
398 | static int dmirror_do_write(struct dmirror *dmirror, unsigned long start, | |
399 | unsigned long end, struct dmirror_bounce *bounce) | |
400 | { | |
401 | unsigned long pfn; | |
402 | void *ptr; | |
403 | ||
404 | ptr = bounce->ptr + ((start - bounce->addr) & PAGE_MASK); | |
405 | ||
406 | for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) { | |
407 | void *entry; | |
408 | struct page *page; | |
409 | void *tmp; | |
410 | ||
411 | entry = xa_load(&dmirror->pt, pfn); | |
412 | page = xa_untag_pointer(entry); | |
413 | if (!page || xa_pointer_tag(entry) != DPT_XA_TAG_WRITE) | |
414 | return -ENOENT; | |
415 | ||
416 | tmp = kmap(page); | |
417 | memcpy(tmp, ptr, PAGE_SIZE); | |
418 | kunmap(page); | |
419 | ||
420 | ptr += PAGE_SIZE; | |
421 | bounce->cpages++; | |
422 | } | |
423 | ||
424 | return 0; | |
425 | } | |
426 | ||
427 | static int dmirror_write(struct dmirror *dmirror, struct hmm_dmirror_cmd *cmd) | |
428 | { | |
429 | struct dmirror_bounce bounce; | |
430 | unsigned long start, end; | |
431 | unsigned long size = cmd->npages << PAGE_SHIFT; | |
432 | int ret; | |
433 | ||
434 | start = cmd->addr; | |
435 | end = start + size; | |
436 | if (end < start) | |
437 | return -EINVAL; | |
438 | ||
439 | ret = dmirror_bounce_init(&bounce, start, size); | |
440 | if (ret) | |
441 | return ret; | |
442 | if (copy_from_user(bounce.ptr, u64_to_user_ptr(cmd->ptr), | |
443 | bounce.size)) { | |
444 | ret = -EFAULT; | |
445 | goto fini; | |
446 | } | |
447 | ||
448 | while (1) { | |
449 | mutex_lock(&dmirror->mutex); | |
450 | ret = dmirror_do_write(dmirror, start, end, &bounce); | |
451 | mutex_unlock(&dmirror->mutex); | |
452 | if (ret != -ENOENT) | |
453 | break; | |
454 | ||
455 | start = cmd->addr + (bounce.cpages << PAGE_SHIFT); | |
456 | ret = dmirror_fault(dmirror, start, end, true); | |
457 | if (ret) | |
458 | break; | |
459 | cmd->faults++; | |
460 | } | |
461 | ||
462 | fini: | |
463 | cmd->cpages = bounce.cpages; | |
464 | dmirror_bounce_fini(&bounce); | |
465 | return ret; | |
466 | } | |
467 | ||
25b80162 | 468 | static int dmirror_allocate_chunk(struct dmirror_device *mdevice, |
b2ef9f5a RC |
469 | struct page **ppage) |
470 | { | |
471 | struct dmirror_chunk *devmem; | |
25b80162 | 472 | struct resource *res = NULL; |
b2ef9f5a RC |
473 | unsigned long pfn; |
474 | unsigned long pfn_first; | |
475 | unsigned long pfn_last; | |
476 | void *ptr; | |
25b80162 | 477 | int ret = -ENOMEM; |
b2ef9f5a | 478 | |
a4574f63 DW |
479 | devmem = kzalloc(sizeof(*devmem), GFP_KERNEL); |
480 | if (!devmem) | |
25b80162 | 481 | return ret; |
a4574f63 | 482 | |
25b80162 AS |
483 | switch (mdevice->zone_device_type) { |
484 | case HMM_DMIRROR_MEMORY_DEVICE_PRIVATE: | |
485 | res = request_free_mem_region(&iomem_resource, DEVMEM_CHUNK_SIZE, | |
486 | "hmm_dmirror"); | |
487 | if (IS_ERR_OR_NULL(res)) | |
488 | goto err_devmem; | |
489 | devmem->pagemap.range.start = res->start; | |
490 | devmem->pagemap.range.end = res->end; | |
491 | devmem->pagemap.type = MEMORY_DEVICE_PRIVATE; | |
492 | break; | |
493 | case HMM_DMIRROR_MEMORY_DEVICE_COHERENT: | |
494 | devmem->pagemap.range.start = (MINOR(mdevice->cdevice.dev) - 2) ? | |
495 | spm_addr_dev0 : | |
496 | spm_addr_dev1; | |
497 | devmem->pagemap.range.end = devmem->pagemap.range.start + | |
498 | DEVMEM_CHUNK_SIZE - 1; | |
499 | devmem->pagemap.type = MEMORY_DEVICE_COHERENT; | |
500 | break; | |
501 | default: | |
502 | ret = -EINVAL; | |
a4574f63 | 503 | goto err_devmem; |
25b80162 | 504 | } |
a4574f63 | 505 | |
b7b3c01b | 506 | devmem->pagemap.nr_range = 1; |
a4574f63 DW |
507 | devmem->pagemap.ops = &dmirror_devmem_ops; |
508 | devmem->pagemap.owner = mdevice; | |
509 | ||
b2ef9f5a RC |
510 | mutex_lock(&mdevice->devmem_lock); |
511 | ||
512 | if (mdevice->devmem_count == mdevice->devmem_capacity) { | |
513 | struct dmirror_chunk **new_chunks; | |
514 | unsigned int new_capacity; | |
515 | ||
516 | new_capacity = mdevice->devmem_capacity + | |
517 | DEVMEM_CHUNKS_RESERVE; | |
518 | new_chunks = krealloc(mdevice->devmem_chunks, | |
519 | sizeof(new_chunks[0]) * new_capacity, | |
520 | GFP_KERNEL); | |
521 | if (!new_chunks) | |
a4574f63 | 522 | goto err_release; |
b2ef9f5a RC |
523 | mdevice->devmem_capacity = new_capacity; |
524 | mdevice->devmem_chunks = new_chunks; | |
525 | } | |
b2ef9f5a | 526 | ptr = memremap_pages(&devmem->pagemap, numa_node_id()); |
25b80162 AS |
527 | if (IS_ERR_OR_NULL(ptr)) { |
528 | if (ptr) | |
529 | ret = PTR_ERR(ptr); | |
530 | else | |
531 | ret = -EFAULT; | |
a4574f63 | 532 | goto err_release; |
25b80162 | 533 | } |
b2ef9f5a RC |
534 | |
535 | devmem->mdevice = mdevice; | |
a4574f63 DW |
536 | pfn_first = devmem->pagemap.range.start >> PAGE_SHIFT; |
537 | pfn_last = pfn_first + (range_len(&devmem->pagemap.range) >> PAGE_SHIFT); | |
b2ef9f5a RC |
538 | mdevice->devmem_chunks[mdevice->devmem_count++] = devmem; |
539 | ||
540 | mutex_unlock(&mdevice->devmem_lock); | |
541 | ||
542 | pr_info("added new %u MB chunk (total %u chunks, %u MB) PFNs [0x%lx 0x%lx)\n", | |
543 | DEVMEM_CHUNK_SIZE / (1024 * 1024), | |
544 | mdevice->devmem_count, | |
545 | mdevice->devmem_count * (DEVMEM_CHUNK_SIZE / (1024 * 1024)), | |
546 | pfn_first, pfn_last); | |
547 | ||
548 | spin_lock(&mdevice->lock); | |
549 | for (pfn = pfn_first; pfn < pfn_last; pfn++) { | |
550 | struct page *page = pfn_to_page(pfn); | |
551 | ||
552 | page->zone_device_data = mdevice->free_pages; | |
553 | mdevice->free_pages = page; | |
554 | } | |
555 | if (ppage) { | |
556 | *ppage = mdevice->free_pages; | |
557 | mdevice->free_pages = (*ppage)->zone_device_data; | |
558 | mdevice->calloc++; | |
559 | } | |
560 | spin_unlock(&mdevice->lock); | |
561 | ||
25b80162 | 562 | return 0; |
b2ef9f5a | 563 | |
b2ef9f5a | 564 | err_release: |
b2ef9f5a | 565 | mutex_unlock(&mdevice->devmem_lock); |
25b80162 AS |
566 | if (res && devmem->pagemap.type == MEMORY_DEVICE_PRIVATE) |
567 | release_mem_region(devmem->pagemap.range.start, | |
568 | range_len(&devmem->pagemap.range)); | |
a4574f63 DW |
569 | err_devmem: |
570 | kfree(devmem); | |
571 | ||
25b80162 | 572 | return ret; |
b2ef9f5a RC |
573 | } |
574 | ||
575 | static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice) | |
576 | { | |
577 | struct page *dpage = NULL; | |
578 | struct page *rpage; | |
579 | ||
580 | /* | |
581 | * This is a fake device so we alloc real system memory to store | |
582 | * our device memory. | |
583 | */ | |
584 | rpage = alloc_page(GFP_HIGHUSER); | |
585 | if (!rpage) | |
586 | return NULL; | |
587 | ||
588 | spin_lock(&mdevice->lock); | |
589 | ||
590 | if (mdevice->free_pages) { | |
591 | dpage = mdevice->free_pages; | |
592 | mdevice->free_pages = dpage->zone_device_data; | |
593 | mdevice->calloc++; | |
594 | spin_unlock(&mdevice->lock); | |
595 | } else { | |
596 | spin_unlock(&mdevice->lock); | |
25b80162 | 597 | if (dmirror_allocate_chunk(mdevice, &dpage)) |
b2ef9f5a RC |
598 | goto error; |
599 | } | |
600 | ||
601 | dpage->zone_device_data = rpage; | |
b2ef9f5a RC |
602 | lock_page(dpage); |
603 | return dpage; | |
604 | ||
605 | error: | |
606 | __free_page(rpage); | |
607 | return NULL; | |
608 | } | |
609 | ||
610 | static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args, | |
611 | struct dmirror *dmirror) | |
612 | { | |
613 | struct dmirror_device *mdevice = dmirror->mdevice; | |
614 | const unsigned long *src = args->src; | |
615 | unsigned long *dst = args->dst; | |
616 | unsigned long addr; | |
617 | ||
618 | for (addr = args->start; addr < args->end; addr += PAGE_SIZE, | |
619 | src++, dst++) { | |
620 | struct page *spage; | |
621 | struct page *dpage; | |
622 | struct page *rpage; | |
623 | ||
624 | if (!(*src & MIGRATE_PFN_MIGRATE)) | |
625 | continue; | |
626 | ||
627 | /* | |
628 | * Note that spage might be NULL which is OK since it is an | |
629 | * unallocated pte_none() or read-only zero page. | |
630 | */ | |
631 | spage = migrate_pfn_to_page(*src); | |
632 | ||
b2ef9f5a RC |
633 | dpage = dmirror_devmem_alloc_page(mdevice); |
634 | if (!dpage) | |
635 | continue; | |
636 | ||
637 | rpage = dpage->zone_device_data; | |
638 | if (spage) | |
639 | copy_highpage(rpage, spage); | |
640 | else | |
641 | clear_highpage(rpage); | |
642 | ||
643 | /* | |
644 | * Normally, a device would use the page->zone_device_data to | |
645 | * point to the mirror but here we use it to hold the page for | |
646 | * the simulated device memory and that page holds the pointer | |
647 | * to the mirror. | |
648 | */ | |
649 | rpage->zone_device_data = dmirror; | |
650 | ||
ab09243a | 651 | *dst = migrate_pfn(page_to_pfn(dpage)); |
b2ef9f5a RC |
652 | if ((*src & MIGRATE_PFN_WRITE) || |
653 | (!spage && args->vma->vm_flags & VM_WRITE)) | |
654 | *dst |= MIGRATE_PFN_WRITE; | |
655 | } | |
656 | } | |
657 | ||
b659baea AP |
658 | static int dmirror_check_atomic(struct dmirror *dmirror, unsigned long start, |
659 | unsigned long end) | |
660 | { | |
661 | unsigned long pfn; | |
662 | ||
663 | for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) { | |
664 | void *entry; | |
b659baea AP |
665 | |
666 | entry = xa_load(&dmirror->pt, pfn); | |
b659baea AP |
667 | if (xa_pointer_tag(entry) == DPT_XA_TAG_ATOMIC) |
668 | return -EPERM; | |
669 | } | |
670 | ||
671 | return 0; | |
672 | } | |
673 | ||
674 | static int dmirror_atomic_map(unsigned long start, unsigned long end, | |
675 | struct page **pages, struct dmirror *dmirror) | |
676 | { | |
677 | unsigned long pfn, mapped = 0; | |
678 | int i; | |
679 | ||
680 | /* Map the migrated pages into the device's page tables. */ | |
681 | mutex_lock(&dmirror->mutex); | |
682 | ||
683 | for (i = 0, pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++, i++) { | |
684 | void *entry; | |
685 | ||
686 | if (!pages[i]) | |
687 | continue; | |
688 | ||
689 | entry = pages[i]; | |
690 | entry = xa_tag_pointer(entry, DPT_XA_TAG_ATOMIC); | |
691 | entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC); | |
692 | if (xa_is_err(entry)) { | |
693 | mutex_unlock(&dmirror->mutex); | |
694 | return xa_err(entry); | |
695 | } | |
696 | ||
697 | mapped++; | |
698 | } | |
699 | ||
700 | mutex_unlock(&dmirror->mutex); | |
701 | return mapped; | |
702 | } | |
703 | ||
b2ef9f5a RC |
704 | static int dmirror_migrate_finalize_and_map(struct migrate_vma *args, |
705 | struct dmirror *dmirror) | |
706 | { | |
707 | unsigned long start = args->start; | |
708 | unsigned long end = args->end; | |
709 | const unsigned long *src = args->src; | |
710 | const unsigned long *dst = args->dst; | |
711 | unsigned long pfn; | |
712 | ||
713 | /* Map the migrated pages into the device's page tables. */ | |
714 | mutex_lock(&dmirror->mutex); | |
715 | ||
716 | for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++, | |
717 | src++, dst++) { | |
718 | struct page *dpage; | |
719 | void *entry; | |
720 | ||
721 | if (!(*src & MIGRATE_PFN_MIGRATE)) | |
722 | continue; | |
723 | ||
724 | dpage = migrate_pfn_to_page(*dst); | |
725 | if (!dpage) | |
726 | continue; | |
727 | ||
728 | /* | |
729 | * Store the page that holds the data so the page table | |
730 | * doesn't have to deal with ZONE_DEVICE private pages. | |
731 | */ | |
732 | entry = dpage->zone_device_data; | |
733 | if (*dst & MIGRATE_PFN_WRITE) | |
734 | entry = xa_tag_pointer(entry, DPT_XA_TAG_WRITE); | |
735 | entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC); | |
736 | if (xa_is_err(entry)) { | |
737 | mutex_unlock(&dmirror->mutex); | |
738 | return xa_err(entry); | |
739 | } | |
740 | } | |
741 | ||
742 | mutex_unlock(&dmirror->mutex); | |
743 | return 0; | |
744 | } | |
745 | ||
b659baea AP |
746 | static int dmirror_exclusive(struct dmirror *dmirror, |
747 | struct hmm_dmirror_cmd *cmd) | |
748 | { | |
749 | unsigned long start, end, addr; | |
750 | unsigned long size = cmd->npages << PAGE_SHIFT; | |
751 | struct mm_struct *mm = dmirror->notifier.mm; | |
752 | struct page *pages[64]; | |
753 | struct dmirror_bounce bounce; | |
754 | unsigned long next; | |
755 | int ret; | |
756 | ||
757 | start = cmd->addr; | |
758 | end = start + size; | |
759 | if (end < start) | |
760 | return -EINVAL; | |
761 | ||
762 | /* Since the mm is for the mirrored process, get a reference first. */ | |
763 | if (!mmget_not_zero(mm)) | |
764 | return -EINVAL; | |
765 | ||
766 | mmap_read_lock(mm); | |
767 | for (addr = start; addr < end; addr = next) { | |
ed913b05 | 768 | unsigned long mapped = 0; |
b659baea AP |
769 | int i; |
770 | ||
771 | if (end < addr + (ARRAY_SIZE(pages) << PAGE_SHIFT)) | |
772 | next = end; | |
773 | else | |
774 | next = addr + (ARRAY_SIZE(pages) << PAGE_SHIFT); | |
775 | ||
776 | ret = make_device_exclusive_range(mm, addr, next, pages, NULL); | |
ed913b05 ML |
777 | /* |
778 | * Do dmirror_atomic_map() iff all pages are marked for | |
779 | * exclusive access to avoid accessing uninitialized | |
780 | * fields of pages. | |
781 | */ | |
782 | if (ret == (next - addr) >> PAGE_SHIFT) | |
783 | mapped = dmirror_atomic_map(addr, next, pages, dmirror); | |
b659baea AP |
784 | for (i = 0; i < ret; i++) { |
785 | if (pages[i]) { | |
786 | unlock_page(pages[i]); | |
787 | put_page(pages[i]); | |
788 | } | |
789 | } | |
790 | ||
791 | if (addr + (mapped << PAGE_SHIFT) < next) { | |
792 | mmap_read_unlock(mm); | |
793 | mmput(mm); | |
794 | return -EBUSY; | |
795 | } | |
796 | } | |
797 | mmap_read_unlock(mm); | |
798 | mmput(mm); | |
799 | ||
800 | /* Return the migrated data for verification. */ | |
801 | ret = dmirror_bounce_init(&bounce, start, size); | |
802 | if (ret) | |
803 | return ret; | |
804 | mutex_lock(&dmirror->mutex); | |
805 | ret = dmirror_do_read(dmirror, start, end, &bounce); | |
806 | mutex_unlock(&dmirror->mutex); | |
807 | if (ret == 0) { | |
808 | if (copy_to_user(u64_to_user_ptr(cmd->ptr), bounce.ptr, | |
809 | bounce.size)) | |
810 | ret = -EFAULT; | |
811 | } | |
812 | ||
813 | cmd->cpages = bounce.cpages; | |
814 | dmirror_bounce_fini(&bounce); | |
815 | return ret; | |
816 | } | |
817 | ||
b2ef9f5a RC |
818 | static int dmirror_migrate(struct dmirror *dmirror, |
819 | struct hmm_dmirror_cmd *cmd) | |
820 | { | |
821 | unsigned long start, end, addr; | |
822 | unsigned long size = cmd->npages << PAGE_SHIFT; | |
823 | struct mm_struct *mm = dmirror->notifier.mm; | |
824 | struct vm_area_struct *vma; | |
825 | unsigned long src_pfns[64]; | |
826 | unsigned long dst_pfns[64]; | |
827 | struct dmirror_bounce bounce; | |
828 | struct migrate_vma args; | |
829 | unsigned long next; | |
830 | int ret; | |
831 | ||
832 | start = cmd->addr; | |
833 | end = start + size; | |
834 | if (end < start) | |
835 | return -EINVAL; | |
836 | ||
837 | /* Since the mm is for the mirrored process, get a reference first. */ | |
838 | if (!mmget_not_zero(mm)) | |
839 | return -EINVAL; | |
840 | ||
89154dd5 | 841 | mmap_read_lock(mm); |
b2ef9f5a | 842 | for (addr = start; addr < end; addr = next) { |
46e6b31d LH |
843 | vma = vma_lookup(mm, addr); |
844 | if (!vma || !(vma->vm_flags & VM_READ)) { | |
b2ef9f5a RC |
845 | ret = -EINVAL; |
846 | goto out; | |
847 | } | |
848 | next = min(end, addr + (ARRAY_SIZE(src_pfns) << PAGE_SHIFT)); | |
849 | if (next > vma->vm_end) | |
850 | next = vma->vm_end; | |
851 | ||
852 | args.vma = vma; | |
853 | args.src = src_pfns; | |
854 | args.dst = dst_pfns; | |
855 | args.start = addr; | |
856 | args.end = next; | |
7d17e83a | 857 | args.pgmap_owner = dmirror->mdevice; |
5143192c | 858 | args.flags = MIGRATE_VMA_SELECT_SYSTEM; |
b2ef9f5a RC |
859 | ret = migrate_vma_setup(&args); |
860 | if (ret) | |
861 | goto out; | |
862 | ||
863 | dmirror_migrate_alloc_and_copy(&args, dmirror); | |
864 | migrate_vma_pages(&args); | |
865 | dmirror_migrate_finalize_and_map(&args, dmirror); | |
866 | migrate_vma_finalize(&args); | |
867 | } | |
89154dd5 | 868 | mmap_read_unlock(mm); |
b2ef9f5a RC |
869 | mmput(mm); |
870 | ||
871 | /* Return the migrated data for verification. */ | |
872 | ret = dmirror_bounce_init(&bounce, start, size); | |
873 | if (ret) | |
874 | return ret; | |
875 | mutex_lock(&dmirror->mutex); | |
876 | ret = dmirror_do_read(dmirror, start, end, &bounce); | |
877 | mutex_unlock(&dmirror->mutex); | |
878 | if (ret == 0) { | |
879 | if (copy_to_user(u64_to_user_ptr(cmd->ptr), bounce.ptr, | |
880 | bounce.size)) | |
881 | ret = -EFAULT; | |
882 | } | |
883 | cmd->cpages = bounce.cpages; | |
884 | dmirror_bounce_fini(&bounce); | |
885 | return ret; | |
886 | ||
887 | out: | |
89154dd5 | 888 | mmap_read_unlock(mm); |
b2ef9f5a RC |
889 | mmput(mm); |
890 | return ret; | |
891 | } | |
892 | ||
893 | static void dmirror_mkentry(struct dmirror *dmirror, struct hmm_range *range, | |
894 | unsigned char *perm, unsigned long entry) | |
895 | { | |
896 | struct page *page; | |
897 | ||
898 | if (entry & HMM_PFN_ERROR) { | |
899 | *perm = HMM_DMIRROR_PROT_ERROR; | |
900 | return; | |
901 | } | |
902 | if (!(entry & HMM_PFN_VALID)) { | |
903 | *perm = HMM_DMIRROR_PROT_NONE; | |
904 | return; | |
905 | } | |
906 | ||
907 | page = hmm_pfn_to_page(entry); | |
908 | if (is_device_private_page(page)) { | |
909 | /* Is the page migrated to this device or some other? */ | |
910 | if (dmirror->mdevice == dmirror_page_to_device(page)) | |
911 | *perm = HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL; | |
912 | else | |
913 | *perm = HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE; | |
914 | } else if (is_zero_pfn(page_to_pfn(page))) | |
915 | *perm = HMM_DMIRROR_PROT_ZERO; | |
916 | else | |
917 | *perm = HMM_DMIRROR_PROT_NONE; | |
918 | if (entry & HMM_PFN_WRITE) | |
919 | *perm |= HMM_DMIRROR_PROT_WRITE; | |
920 | else | |
921 | *perm |= HMM_DMIRROR_PROT_READ; | |
e478425b RC |
922 | if (hmm_pfn_to_map_order(entry) + PAGE_SHIFT == PMD_SHIFT) |
923 | *perm |= HMM_DMIRROR_PROT_PMD; | |
924 | else if (hmm_pfn_to_map_order(entry) + PAGE_SHIFT == PUD_SHIFT) | |
925 | *perm |= HMM_DMIRROR_PROT_PUD; | |
b2ef9f5a RC |
926 | } |
927 | ||
928 | static bool dmirror_snapshot_invalidate(struct mmu_interval_notifier *mni, | |
929 | const struct mmu_notifier_range *range, | |
930 | unsigned long cur_seq) | |
931 | { | |
932 | struct dmirror_interval *dmi = | |
933 | container_of(mni, struct dmirror_interval, notifier); | |
934 | struct dmirror *dmirror = dmi->dmirror; | |
935 | ||
936 | if (mmu_notifier_range_blockable(range)) | |
937 | mutex_lock(&dmirror->mutex); | |
938 | else if (!mutex_trylock(&dmirror->mutex)) | |
939 | return false; | |
940 | ||
941 | /* | |
942 | * Snapshots only need to set the sequence number since any | |
943 | * invalidation in the interval invalidates the whole snapshot. | |
944 | */ | |
945 | mmu_interval_set_seq(mni, cur_seq); | |
946 | ||
947 | mutex_unlock(&dmirror->mutex); | |
948 | return true; | |
949 | } | |
950 | ||
951 | static const struct mmu_interval_notifier_ops dmirror_mrn_ops = { | |
952 | .invalidate = dmirror_snapshot_invalidate, | |
953 | }; | |
954 | ||
955 | static int dmirror_range_snapshot(struct dmirror *dmirror, | |
956 | struct hmm_range *range, | |
957 | unsigned char *perm) | |
958 | { | |
959 | struct mm_struct *mm = dmirror->notifier.mm; | |
960 | struct dmirror_interval notifier; | |
961 | unsigned long timeout = | |
962 | jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT); | |
963 | unsigned long i; | |
964 | unsigned long n; | |
965 | int ret = 0; | |
966 | ||
967 | notifier.dmirror = dmirror; | |
968 | range->notifier = ¬ifier.notifier; | |
969 | ||
970 | ret = mmu_interval_notifier_insert(range->notifier, mm, | |
971 | range->start, range->end - range->start, | |
972 | &dmirror_mrn_ops); | |
973 | if (ret) | |
974 | return ret; | |
975 | ||
976 | while (true) { | |
977 | if (time_after(jiffies, timeout)) { | |
978 | ret = -EBUSY; | |
979 | goto out; | |
980 | } | |
981 | ||
982 | range->notifier_seq = mmu_interval_read_begin(range->notifier); | |
983 | ||
89154dd5 | 984 | mmap_read_lock(mm); |
b2ef9f5a | 985 | ret = hmm_range_fault(range); |
89154dd5 | 986 | mmap_read_unlock(mm); |
b2ef9f5a RC |
987 | if (ret) { |
988 | if (ret == -EBUSY) | |
989 | continue; | |
990 | goto out; | |
991 | } | |
992 | ||
993 | mutex_lock(&dmirror->mutex); | |
994 | if (mmu_interval_read_retry(range->notifier, | |
995 | range->notifier_seq)) { | |
996 | mutex_unlock(&dmirror->mutex); | |
997 | continue; | |
998 | } | |
999 | break; | |
1000 | } | |
1001 | ||
1002 | n = (range->end - range->start) >> PAGE_SHIFT; | |
1003 | for (i = 0; i < n; i++) | |
1004 | dmirror_mkentry(dmirror, range, perm + i, range->hmm_pfns[i]); | |
1005 | ||
1006 | mutex_unlock(&dmirror->mutex); | |
1007 | out: | |
1008 | mmu_interval_notifier_remove(range->notifier); | |
1009 | return ret; | |
1010 | } | |
1011 | ||
1012 | static int dmirror_snapshot(struct dmirror *dmirror, | |
1013 | struct hmm_dmirror_cmd *cmd) | |
1014 | { | |
1015 | struct mm_struct *mm = dmirror->notifier.mm; | |
1016 | unsigned long start, end; | |
1017 | unsigned long size = cmd->npages << PAGE_SHIFT; | |
1018 | unsigned long addr; | |
1019 | unsigned long next; | |
1020 | unsigned long pfns[64]; | |
1021 | unsigned char perm[64]; | |
1022 | char __user *uptr; | |
1023 | struct hmm_range range = { | |
1024 | .hmm_pfns = pfns, | |
1025 | .dev_private_owner = dmirror->mdevice, | |
1026 | }; | |
1027 | int ret = 0; | |
1028 | ||
1029 | start = cmd->addr; | |
1030 | end = start + size; | |
1031 | if (end < start) | |
1032 | return -EINVAL; | |
1033 | ||
1034 | /* Since the mm is for the mirrored process, get a reference first. */ | |
1035 | if (!mmget_not_zero(mm)) | |
1036 | return -EINVAL; | |
1037 | ||
1038 | /* | |
1039 | * Register a temporary notifier to detect invalidations even if it | |
1040 | * overlaps with other mmu_interval_notifiers. | |
1041 | */ | |
1042 | uptr = u64_to_user_ptr(cmd->ptr); | |
1043 | for (addr = start; addr < end; addr = next) { | |
1044 | unsigned long n; | |
1045 | ||
1046 | next = min(addr + (ARRAY_SIZE(pfns) << PAGE_SHIFT), end); | |
1047 | range.start = addr; | |
1048 | range.end = next; | |
1049 | ||
1050 | ret = dmirror_range_snapshot(dmirror, &range, perm); | |
1051 | if (ret) | |
1052 | break; | |
1053 | ||
1054 | n = (range.end - range.start) >> PAGE_SHIFT; | |
1055 | if (copy_to_user(uptr, perm, n)) { | |
1056 | ret = -EFAULT; | |
1057 | break; | |
1058 | } | |
1059 | ||
1060 | cmd->cpages += n; | |
1061 | uptr += n; | |
1062 | } | |
1063 | mmput(mm); | |
1064 | ||
1065 | return ret; | |
1066 | } | |
1067 | ||
1068 | static long dmirror_fops_unlocked_ioctl(struct file *filp, | |
1069 | unsigned int command, | |
1070 | unsigned long arg) | |
1071 | { | |
1072 | void __user *uarg = (void __user *)arg; | |
1073 | struct hmm_dmirror_cmd cmd; | |
1074 | struct dmirror *dmirror; | |
1075 | int ret; | |
1076 | ||
1077 | dmirror = filp->private_data; | |
1078 | if (!dmirror) | |
1079 | return -EINVAL; | |
1080 | ||
1081 | if (copy_from_user(&cmd, uarg, sizeof(cmd))) | |
1082 | return -EFAULT; | |
1083 | ||
1084 | if (cmd.addr & ~PAGE_MASK) | |
1085 | return -EINVAL; | |
1086 | if (cmd.addr >= (cmd.addr + (cmd.npages << PAGE_SHIFT))) | |
1087 | return -EINVAL; | |
1088 | ||
1089 | cmd.cpages = 0; | |
1090 | cmd.faults = 0; | |
1091 | ||
1092 | switch (command) { | |
1093 | case HMM_DMIRROR_READ: | |
1094 | ret = dmirror_read(dmirror, &cmd); | |
1095 | break; | |
1096 | ||
1097 | case HMM_DMIRROR_WRITE: | |
1098 | ret = dmirror_write(dmirror, &cmd); | |
1099 | break; | |
1100 | ||
1101 | case HMM_DMIRROR_MIGRATE: | |
1102 | ret = dmirror_migrate(dmirror, &cmd); | |
1103 | break; | |
1104 | ||
b659baea AP |
1105 | case HMM_DMIRROR_EXCLUSIVE: |
1106 | ret = dmirror_exclusive(dmirror, &cmd); | |
1107 | break; | |
1108 | ||
1109 | case HMM_DMIRROR_CHECK_EXCLUSIVE: | |
1110 | ret = dmirror_check_atomic(dmirror, cmd.addr, | |
1111 | cmd.addr + (cmd.npages << PAGE_SHIFT)); | |
1112 | break; | |
1113 | ||
b2ef9f5a RC |
1114 | case HMM_DMIRROR_SNAPSHOT: |
1115 | ret = dmirror_snapshot(dmirror, &cmd); | |
1116 | break; | |
1117 | ||
1118 | default: | |
1119 | return -EINVAL; | |
1120 | } | |
1121 | if (ret) | |
1122 | return ret; | |
1123 | ||
1124 | if (copy_to_user(uarg, &cmd, sizeof(cmd))) | |
1125 | return -EFAULT; | |
1126 | ||
1127 | return 0; | |
1128 | } | |
1129 | ||
87c01d57 AP |
1130 | static int dmirror_fops_mmap(struct file *file, struct vm_area_struct *vma) |
1131 | { | |
1132 | unsigned long addr; | |
1133 | ||
1134 | for (addr = vma->vm_start; addr < vma->vm_end; addr += PAGE_SIZE) { | |
1135 | struct page *page; | |
1136 | int ret; | |
1137 | ||
1138 | page = alloc_page(GFP_KERNEL | __GFP_ZERO); | |
1139 | if (!page) | |
1140 | return -ENOMEM; | |
1141 | ||
1142 | ret = vm_insert_page(vma, addr, page); | |
1143 | if (ret) { | |
1144 | __free_page(page); | |
1145 | return ret; | |
1146 | } | |
1147 | put_page(page); | |
1148 | } | |
1149 | ||
1150 | return 0; | |
1151 | } | |
1152 | ||
b2ef9f5a RC |
1153 | static const struct file_operations dmirror_fops = { |
1154 | .open = dmirror_fops_open, | |
1155 | .release = dmirror_fops_release, | |
87c01d57 | 1156 | .mmap = dmirror_fops_mmap, |
b2ef9f5a RC |
1157 | .unlocked_ioctl = dmirror_fops_unlocked_ioctl, |
1158 | .llseek = default_llseek, | |
1159 | .owner = THIS_MODULE, | |
1160 | }; | |
1161 | ||
1162 | static void dmirror_devmem_free(struct page *page) | |
1163 | { | |
1164 | struct page *rpage = page->zone_device_data; | |
1165 | struct dmirror_device *mdevice; | |
1166 | ||
1167 | if (rpage) | |
1168 | __free_page(rpage); | |
1169 | ||
1170 | mdevice = dmirror_page_to_device(page); | |
1171 | ||
1172 | spin_lock(&mdevice->lock); | |
1173 | mdevice->cfree++; | |
1174 | page->zone_device_data = mdevice->free_pages; | |
1175 | mdevice->free_pages = page; | |
1176 | spin_unlock(&mdevice->lock); | |
1177 | } | |
1178 | ||
1179 | static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args, | |
7d17e83a | 1180 | struct dmirror *dmirror) |
b2ef9f5a RC |
1181 | { |
1182 | const unsigned long *src = args->src; | |
1183 | unsigned long *dst = args->dst; | |
1184 | unsigned long start = args->start; | |
1185 | unsigned long end = args->end; | |
1186 | unsigned long addr; | |
1187 | ||
1188 | for (addr = start; addr < end; addr += PAGE_SIZE, | |
1189 | src++, dst++) { | |
1190 | struct page *dpage, *spage; | |
1191 | ||
1192 | spage = migrate_pfn_to_page(*src); | |
1193 | if (!spage || !(*src & MIGRATE_PFN_MIGRATE)) | |
1194 | continue; | |
1195 | spage = spage->zone_device_data; | |
1196 | ||
1197 | dpage = alloc_page_vma(GFP_HIGHUSER_MOVABLE, args->vma, addr); | |
1198 | if (!dpage) | |
1199 | continue; | |
1200 | ||
1201 | lock_page(dpage); | |
7d17e83a | 1202 | xa_erase(&dmirror->pt, addr >> PAGE_SHIFT); |
b2ef9f5a | 1203 | copy_highpage(dpage, spage); |
ab09243a | 1204 | *dst = migrate_pfn(page_to_pfn(dpage)); |
b2ef9f5a RC |
1205 | if (*src & MIGRATE_PFN_WRITE) |
1206 | *dst |= MIGRATE_PFN_WRITE; | |
1207 | } | |
1208 | return 0; | |
1209 | } | |
1210 | ||
b2ef9f5a RC |
1211 | static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf) |
1212 | { | |
1213 | struct migrate_vma args; | |
1214 | unsigned long src_pfns; | |
1215 | unsigned long dst_pfns; | |
1216 | struct page *rpage; | |
1217 | struct dmirror *dmirror; | |
1218 | vm_fault_t ret; | |
1219 | ||
1220 | /* | |
1221 | * Normally, a device would use the page->zone_device_data to point to | |
1222 | * the mirror but here we use it to hold the page for the simulated | |
1223 | * device memory and that page holds the pointer to the mirror. | |
1224 | */ | |
1225 | rpage = vmf->page->zone_device_data; | |
1226 | dmirror = rpage->zone_device_data; | |
1227 | ||
1228 | /* FIXME demonstrate how we can adjust migrate range */ | |
1229 | args.vma = vmf->vma; | |
1230 | args.start = vmf->address; | |
1231 | args.end = args.start + PAGE_SIZE; | |
1232 | args.src = &src_pfns; | |
1233 | args.dst = &dst_pfns; | |
5143192c RC |
1234 | args.pgmap_owner = dmirror->mdevice; |
1235 | args.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE; | |
b2ef9f5a RC |
1236 | |
1237 | if (migrate_vma_setup(&args)) | |
1238 | return VM_FAULT_SIGBUS; | |
1239 | ||
7d17e83a | 1240 | ret = dmirror_devmem_fault_alloc_and_copy(&args, dmirror); |
b2ef9f5a RC |
1241 | if (ret) |
1242 | return ret; | |
1243 | migrate_vma_pages(&args); | |
7d17e83a RC |
1244 | /* |
1245 | * No device finalize step is needed since | |
1246 | * dmirror_devmem_fault_alloc_and_copy() will have already | |
1247 | * invalidated the device page table. | |
1248 | */ | |
b2ef9f5a RC |
1249 | migrate_vma_finalize(&args); |
1250 | return 0; | |
1251 | } | |
1252 | ||
1253 | static const struct dev_pagemap_ops dmirror_devmem_ops = { | |
1254 | .page_free = dmirror_devmem_free, | |
1255 | .migrate_to_ram = dmirror_devmem_fault, | |
1256 | }; | |
1257 | ||
1258 | static int dmirror_device_init(struct dmirror_device *mdevice, int id) | |
1259 | { | |
1260 | dev_t dev; | |
1261 | int ret; | |
1262 | ||
1263 | dev = MKDEV(MAJOR(dmirror_dev), id); | |
1264 | mutex_init(&mdevice->devmem_lock); | |
1265 | spin_lock_init(&mdevice->lock); | |
1266 | ||
1267 | cdev_init(&mdevice->cdevice, &dmirror_fops); | |
1268 | mdevice->cdevice.owner = THIS_MODULE; | |
1269 | ret = cdev_add(&mdevice->cdevice, dev, 1); | |
1270 | if (ret) | |
1271 | return ret; | |
1272 | ||
25b80162 AS |
1273 | /* Build a list of free ZONE_DEVICE struct pages */ |
1274 | return dmirror_allocate_chunk(mdevice, NULL); | |
b2ef9f5a RC |
1275 | } |
1276 | ||
1277 | static void dmirror_device_remove(struct dmirror_device *mdevice) | |
1278 | { | |
1279 | unsigned int i; | |
1280 | ||
1281 | if (mdevice->devmem_chunks) { | |
1282 | for (i = 0; i < mdevice->devmem_count; i++) { | |
1283 | struct dmirror_chunk *devmem = | |
1284 | mdevice->devmem_chunks[i]; | |
1285 | ||
1286 | memunmap_pages(&devmem->pagemap); | |
25b80162 AS |
1287 | if (devmem->pagemap.type == MEMORY_DEVICE_PRIVATE) |
1288 | release_mem_region(devmem->pagemap.range.start, | |
1289 | range_len(&devmem->pagemap.range)); | |
b2ef9f5a RC |
1290 | kfree(devmem); |
1291 | } | |
1292 | kfree(mdevice->devmem_chunks); | |
1293 | } | |
1294 | ||
1295 | cdev_del(&mdevice->cdevice); | |
1296 | } | |
1297 | ||
1298 | static int __init hmm_dmirror_init(void) | |
1299 | { | |
1300 | int ret; | |
188f4826 AS |
1301 | int id = 0; |
1302 | int ndevices = 0; | |
b2ef9f5a RC |
1303 | |
1304 | ret = alloc_chrdev_region(&dmirror_dev, 0, DMIRROR_NDEVICES, | |
1305 | "HMM_DMIRROR"); | |
1306 | if (ret) | |
1307 | goto err_unreg; | |
1308 | ||
188f4826 AS |
1309 | memset(dmirror_devices, 0, DMIRROR_NDEVICES * sizeof(dmirror_devices[0])); |
1310 | dmirror_devices[ndevices++].zone_device_type = | |
1311 | HMM_DMIRROR_MEMORY_DEVICE_PRIVATE; | |
1312 | dmirror_devices[ndevices++].zone_device_type = | |
1313 | HMM_DMIRROR_MEMORY_DEVICE_PRIVATE; | |
1314 | for (id = 0; id < ndevices; id++) { | |
b2ef9f5a RC |
1315 | ret = dmirror_device_init(dmirror_devices + id, id); |
1316 | if (ret) | |
1317 | goto err_chrdev; | |
1318 | } | |
1319 | ||
b2ef9f5a RC |
1320 | pr_info("HMM test module loaded. This is only for testing HMM.\n"); |
1321 | return 0; | |
1322 | ||
1323 | err_chrdev: | |
1324 | while (--id >= 0) | |
1325 | dmirror_device_remove(dmirror_devices + id); | |
1326 | unregister_chrdev_region(dmirror_dev, DMIRROR_NDEVICES); | |
1327 | err_unreg: | |
1328 | return ret; | |
1329 | } | |
1330 | ||
1331 | static void __exit hmm_dmirror_exit(void) | |
1332 | { | |
1333 | int id; | |
1334 | ||
b2ef9f5a RC |
1335 | for (id = 0; id < DMIRROR_NDEVICES; id++) |
1336 | dmirror_device_remove(dmirror_devices + id); | |
1337 | unregister_chrdev_region(dmirror_dev, DMIRROR_NDEVICES); | |
1338 | } | |
1339 | ||
1340 | module_init(hmm_dmirror_init); | |
1341 | module_exit(hmm_dmirror_exit); | |
1342 | MODULE_LICENSE("GPL"); |