Commit | Line | Data |
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c942fddf | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
133ff0ea JG |
2 | /* |
3 | * Copyright 2013 Red Hat Inc. | |
4 | * | |
f813f219 | 5 | * Authors: Jérôme Glisse <jglisse@redhat.com> |
133ff0ea JG |
6 | */ |
7 | /* | |
8 | * Refer to include/linux/hmm.h for information about heterogeneous memory | |
9 | * management or HMM for short. | |
10 | */ | |
a520110e | 11 | #include <linux/pagewalk.h> |
133ff0ea | 12 | #include <linux/hmm.h> |
858b54da | 13 | #include <linux/init.h> |
da4c3c73 JG |
14 | #include <linux/rmap.h> |
15 | #include <linux/swap.h> | |
133ff0ea JG |
16 | #include <linux/slab.h> |
17 | #include <linux/sched.h> | |
4ef589dc JG |
18 | #include <linux/mmzone.h> |
19 | #include <linux/pagemap.h> | |
da4c3c73 JG |
20 | #include <linux/swapops.h> |
21 | #include <linux/hugetlb.h> | |
4ef589dc | 22 | #include <linux/memremap.h> |
c8a53b2d | 23 | #include <linux/sched/mm.h> |
7b2d55d2 | 24 | #include <linux/jump_label.h> |
55c0ece8 | 25 | #include <linux/dma-mapping.h> |
c0b12405 | 26 | #include <linux/mmu_notifier.h> |
4ef589dc JG |
27 | #include <linux/memory_hotplug.h> |
28 | ||
74eee180 JG |
29 | struct hmm_vma_walk { |
30 | struct hmm_range *range; | |
992de9a8 | 31 | struct dev_pagemap *pgmap; |
74eee180 | 32 | unsigned long last; |
9a4903e4 | 33 | unsigned int flags; |
74eee180 JG |
34 | }; |
35 | ||
d28c2c9a RC |
36 | static int hmm_pfns_fill(unsigned long addr, unsigned long end, |
37 | struct hmm_range *range, enum hmm_pfn_value_e value) | |
da4c3c73 | 38 | { |
ff05c0c6 | 39 | uint64_t *pfns = range->pfns; |
da4c3c73 JG |
40 | unsigned long i; |
41 | ||
42 | i = (addr - range->start) >> PAGE_SHIFT; | |
43 | for (; addr < end; addr += PAGE_SIZE, i++) | |
d28c2c9a | 44 | pfns[i] = range->values[value]; |
da4c3c73 JG |
45 | |
46 | return 0; | |
47 | } | |
48 | ||
5504ed29 | 49 | /* |
f8c888a3 | 50 | * hmm_vma_fault() - fault in a range lacking valid pmd or pte(s) |
d2e8d551 | 51 | * @addr: range virtual start address (inclusive) |
5504ed29 | 52 | * @end: range virtual end address (exclusive) |
2aee09d8 JG |
53 | * @fault: should we fault or not ? |
54 | * @write_fault: write fault ? | |
5504ed29 | 55 | * @walk: mm_walk structure |
f8c888a3 | 56 | * Return: -EBUSY after page fault, or page fault error |
5504ed29 JG |
57 | * |
58 | * This function will be called whenever pmd_none() or pte_none() returns true, | |
59 | * or whenever there is no page directory covering the virtual address range. | |
60 | */ | |
f8c888a3 | 61 | static int hmm_vma_fault(unsigned long addr, unsigned long end, |
2aee09d8 JG |
62 | bool fault, bool write_fault, |
63 | struct mm_walk *walk) | |
da4c3c73 | 64 | { |
74eee180 JG |
65 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
66 | struct hmm_range *range = hmm_vma_walk->range; | |
5a0c38d3 | 67 | struct vm_area_struct *vma = walk->vma; |
ff05c0c6 | 68 | uint64_t *pfns = range->pfns; |
f8c888a3 | 69 | unsigned long i = (addr - range->start) >> PAGE_SHIFT; |
5a0c38d3 | 70 | unsigned int fault_flags = FAULT_FLAG_REMOTE; |
da4c3c73 | 71 | |
f8c888a3 | 72 | WARN_ON_ONCE(!fault && !write_fault); |
74eee180 | 73 | hmm_vma_walk->last = addr; |
63d5066f | 74 | |
5a0c38d3 CH |
75 | if (!vma) |
76 | goto out_error; | |
da4c3c73 | 77 | |
5a0c38d3 CH |
78 | if (write_fault) { |
79 | if (!(vma->vm_flags & VM_WRITE)) | |
80 | return -EPERM; | |
81 | fault_flags |= FAULT_FLAG_WRITE; | |
74eee180 JG |
82 | } |
83 | ||
5a0c38d3 CH |
84 | for (; addr < end; addr += PAGE_SIZE, i++) |
85 | if (handle_mm_fault(vma, addr, fault_flags) & VM_FAULT_ERROR) | |
86 | goto out_error; | |
87 | ||
f8c888a3 | 88 | return -EBUSY; |
5a0c38d3 CH |
89 | |
90 | out_error: | |
91 | pfns[i] = range->values[HMM_PFN_ERROR]; | |
92 | return -EFAULT; | |
2aee09d8 JG |
93 | } |
94 | ||
95 | static inline void hmm_pte_need_fault(const struct hmm_vma_walk *hmm_vma_walk, | |
96 | uint64_t pfns, uint64_t cpu_flags, | |
97 | bool *fault, bool *write_fault) | |
98 | { | |
f88a1e90 JG |
99 | struct hmm_range *range = hmm_vma_walk->range; |
100 | ||
d45d464b | 101 | if (hmm_vma_walk->flags & HMM_FAULT_SNAPSHOT) |
2aee09d8 JG |
102 | return; |
103 | ||
023a019a JG |
104 | /* |
105 | * So we not only consider the individual per page request we also | |
106 | * consider the default flags requested for the range. The API can | |
d2e8d551 RC |
107 | * be used 2 ways. The first one where the HMM user coalesces |
108 | * multiple page faults into one request and sets flags per pfn for | |
109 | * those faults. The second one where the HMM user wants to pre- | |
023a019a JG |
110 | * fault a range with specific flags. For the latter one it is a |
111 | * waste to have the user pre-fill the pfn arrays with a default | |
112 | * flags value. | |
113 | */ | |
114 | pfns = (pfns & range->pfn_flags_mask) | range->default_flags; | |
115 | ||
2aee09d8 | 116 | /* We aren't ask to do anything ... */ |
f88a1e90 | 117 | if (!(pfns & range->flags[HMM_PFN_VALID])) |
2aee09d8 | 118 | return; |
f88a1e90 JG |
119 | |
120 | /* If CPU page table is not valid then we need to fault */ | |
121 | *fault = !(cpu_flags & range->flags[HMM_PFN_VALID]); | |
122 | /* Need to write fault ? */ | |
123 | if ((pfns & range->flags[HMM_PFN_WRITE]) && | |
124 | !(cpu_flags & range->flags[HMM_PFN_WRITE])) { | |
125 | *write_fault = true; | |
2aee09d8 JG |
126 | *fault = true; |
127 | } | |
128 | } | |
129 | ||
130 | static void hmm_range_need_fault(const struct hmm_vma_walk *hmm_vma_walk, | |
131 | const uint64_t *pfns, unsigned long npages, | |
132 | uint64_t cpu_flags, bool *fault, | |
133 | bool *write_fault) | |
134 | { | |
135 | unsigned long i; | |
136 | ||
d45d464b | 137 | if (hmm_vma_walk->flags & HMM_FAULT_SNAPSHOT) { |
2aee09d8 JG |
138 | *fault = *write_fault = false; |
139 | return; | |
140 | } | |
141 | ||
a3e0d41c | 142 | *fault = *write_fault = false; |
2aee09d8 JG |
143 | for (i = 0; i < npages; ++i) { |
144 | hmm_pte_need_fault(hmm_vma_walk, pfns[i], cpu_flags, | |
145 | fault, write_fault); | |
a3e0d41c | 146 | if ((*write_fault)) |
2aee09d8 JG |
147 | return; |
148 | } | |
149 | } | |
150 | ||
151 | static int hmm_vma_walk_hole(unsigned long addr, unsigned long end, | |
b7a16c7a | 152 | __always_unused int depth, struct mm_walk *walk) |
2aee09d8 JG |
153 | { |
154 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
155 | struct hmm_range *range = hmm_vma_walk->range; | |
156 | bool fault, write_fault; | |
157 | unsigned long i, npages; | |
158 | uint64_t *pfns; | |
159 | ||
160 | i = (addr - range->start) >> PAGE_SHIFT; | |
161 | npages = (end - addr) >> PAGE_SHIFT; | |
162 | pfns = &range->pfns[i]; | |
163 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, | |
164 | 0, &fault, &write_fault); | |
f8c888a3 CH |
165 | if (fault || write_fault) |
166 | return hmm_vma_fault(addr, end, fault, write_fault, walk); | |
167 | hmm_vma_walk->last = addr; | |
168 | return hmm_pfns_fill(addr, end, range, HMM_PFN_NONE); | |
2aee09d8 JG |
169 | } |
170 | ||
f88a1e90 | 171 | static inline uint64_t pmd_to_hmm_pfn_flags(struct hmm_range *range, pmd_t pmd) |
2aee09d8 JG |
172 | { |
173 | if (pmd_protnone(pmd)) | |
174 | return 0; | |
f88a1e90 JG |
175 | return pmd_write(pmd) ? range->flags[HMM_PFN_VALID] | |
176 | range->flags[HMM_PFN_WRITE] : | |
177 | range->flags[HMM_PFN_VALID]; | |
da4c3c73 JG |
178 | } |
179 | ||
992de9a8 | 180 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
9d3973d6 CH |
181 | static int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr, |
182 | unsigned long end, uint64_t *pfns, pmd_t pmd) | |
183 | { | |
53f5c3f4 | 184 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
f88a1e90 | 185 | struct hmm_range *range = hmm_vma_walk->range; |
2aee09d8 | 186 | unsigned long pfn, npages, i; |
2aee09d8 | 187 | bool fault, write_fault; |
f88a1e90 | 188 | uint64_t cpu_flags; |
53f5c3f4 | 189 | |
2aee09d8 | 190 | npages = (end - addr) >> PAGE_SHIFT; |
f88a1e90 | 191 | cpu_flags = pmd_to_hmm_pfn_flags(range, pmd); |
2aee09d8 JG |
192 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, cpu_flags, |
193 | &fault, &write_fault); | |
53f5c3f4 | 194 | |
24cee8ab | 195 | if (fault || write_fault) |
f8c888a3 | 196 | return hmm_vma_fault(addr, end, fault, write_fault, walk); |
53f5c3f4 | 197 | |
309f9a4f | 198 | pfn = pmd_pfn(pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT); |
992de9a8 JG |
199 | for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++) { |
200 | if (pmd_devmap(pmd)) { | |
201 | hmm_vma_walk->pgmap = get_dev_pagemap(pfn, | |
202 | hmm_vma_walk->pgmap); | |
203 | if (unlikely(!hmm_vma_walk->pgmap)) | |
204 | return -EBUSY; | |
205 | } | |
391aab11 | 206 | pfns[i] = hmm_device_entry_from_pfn(range, pfn) | cpu_flags; |
992de9a8 JG |
207 | } |
208 | if (hmm_vma_walk->pgmap) { | |
209 | put_dev_pagemap(hmm_vma_walk->pgmap); | |
210 | hmm_vma_walk->pgmap = NULL; | |
211 | } | |
53f5c3f4 JG |
212 | hmm_vma_walk->last = end; |
213 | return 0; | |
214 | } | |
9d3973d6 CH |
215 | #else /* CONFIG_TRANSPARENT_HUGEPAGE */ |
216 | /* stub to allow the code below to compile */ | |
217 | int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr, | |
218 | unsigned long end, uint64_t *pfns, pmd_t pmd); | |
219 | #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ | |
53f5c3f4 | 220 | |
08ddddda CH |
221 | static inline bool hmm_is_device_private_entry(struct hmm_range *range, |
222 | swp_entry_t entry) | |
223 | { | |
224 | return is_device_private_entry(entry) && | |
225 | device_private_entry_to_page(entry)->pgmap->owner == | |
226 | range->dev_private_owner; | |
227 | } | |
228 | ||
f88a1e90 | 229 | static inline uint64_t pte_to_hmm_pfn_flags(struct hmm_range *range, pte_t pte) |
2aee09d8 | 230 | { |
789c2af8 | 231 | if (pte_none(pte) || !pte_present(pte) || pte_protnone(pte)) |
2aee09d8 | 232 | return 0; |
f88a1e90 JG |
233 | return pte_write(pte) ? range->flags[HMM_PFN_VALID] | |
234 | range->flags[HMM_PFN_WRITE] : | |
235 | range->flags[HMM_PFN_VALID]; | |
2aee09d8 JG |
236 | } |
237 | ||
53f5c3f4 JG |
238 | static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr, |
239 | unsigned long end, pmd_t *pmdp, pte_t *ptep, | |
240 | uint64_t *pfn) | |
241 | { | |
242 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
f88a1e90 | 243 | struct hmm_range *range = hmm_vma_walk->range; |
2aee09d8 JG |
244 | bool fault, write_fault; |
245 | uint64_t cpu_flags; | |
53f5c3f4 | 246 | pte_t pte = *ptep; |
f88a1e90 | 247 | uint64_t orig_pfn = *pfn; |
53f5c3f4 | 248 | |
f88a1e90 | 249 | *pfn = range->values[HMM_PFN_NONE]; |
73231612 | 250 | fault = write_fault = false; |
53f5c3f4 JG |
251 | |
252 | if (pte_none(pte)) { | |
73231612 JG |
253 | hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0, |
254 | &fault, &write_fault); | |
2aee09d8 | 255 | if (fault || write_fault) |
53f5c3f4 JG |
256 | goto fault; |
257 | return 0; | |
258 | } | |
259 | ||
260 | if (!pte_present(pte)) { | |
261 | swp_entry_t entry = pte_to_swp_entry(pte); | |
262 | ||
53f5c3f4 | 263 | /* |
17ffdc48 CH |
264 | * Never fault in device private pages pages, but just report |
265 | * the PFN even if not present. | |
53f5c3f4 | 266 | */ |
08ddddda | 267 | if (hmm_is_device_private_entry(range, entry)) { |
391aab11 JG |
268 | *pfn = hmm_device_entry_from_pfn(range, |
269 | swp_offset(entry)); | |
17ffdc48 CH |
270 | *pfn |= range->flags[HMM_PFN_VALID]; |
271 | if (is_write_device_private_entry(entry)) | |
272 | *pfn |= range->flags[HMM_PFN_WRITE]; | |
53f5c3f4 JG |
273 | return 0; |
274 | } | |
275 | ||
76612d6c JG |
276 | hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0, &fault, |
277 | &write_fault); | |
278 | if (!fault && !write_fault) | |
53f5c3f4 | 279 | return 0; |
76612d6c JG |
280 | |
281 | if (!non_swap_entry(entry)) | |
282 | goto fault; | |
283 | ||
284 | if (is_migration_entry(entry)) { | |
285 | pte_unmap(ptep); | |
286 | hmm_vma_walk->last = addr; | |
287 | migration_entry_wait(walk->mm, pmdp, addr); | |
288 | return -EBUSY; | |
53f5c3f4 JG |
289 | } |
290 | ||
291 | /* Report error for everything else */ | |
dfdc2207 | 292 | pte_unmap(ptep); |
f88a1e90 | 293 | *pfn = range->values[HMM_PFN_ERROR]; |
53f5c3f4 JG |
294 | return -EFAULT; |
295 | } | |
296 | ||
76612d6c JG |
297 | cpu_flags = pte_to_hmm_pfn_flags(range, pte); |
298 | hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags, &fault, | |
299 | &write_fault); | |
2aee09d8 | 300 | if (fault || write_fault) |
53f5c3f4 JG |
301 | goto fault; |
302 | ||
992de9a8 JG |
303 | if (pte_devmap(pte)) { |
304 | hmm_vma_walk->pgmap = get_dev_pagemap(pte_pfn(pte), | |
305 | hmm_vma_walk->pgmap); | |
dfdc2207 JG |
306 | if (unlikely(!hmm_vma_walk->pgmap)) { |
307 | pte_unmap(ptep); | |
992de9a8 | 308 | return -EBUSY; |
dfdc2207 | 309 | } |
40550627 JG |
310 | } |
311 | ||
312 | /* | |
313 | * Since each architecture defines a struct page for the zero page, just | |
314 | * fall through and treat it like a normal page. | |
315 | */ | |
316 | if (pte_special(pte) && !is_zero_pfn(pte_pfn(pte))) { | |
317 | hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0, &fault, | |
318 | &write_fault); | |
319 | if (fault || write_fault) { | |
dfdc2207 | 320 | pte_unmap(ptep); |
ac541f25 RC |
321 | return -EFAULT; |
322 | } | |
40550627 JG |
323 | *pfn = range->values[HMM_PFN_SPECIAL]; |
324 | return 0; | |
992de9a8 JG |
325 | } |
326 | ||
391aab11 | 327 | *pfn = hmm_device_entry_from_pfn(range, pte_pfn(pte)) | cpu_flags; |
53f5c3f4 JG |
328 | return 0; |
329 | ||
330 | fault: | |
992de9a8 JG |
331 | if (hmm_vma_walk->pgmap) { |
332 | put_dev_pagemap(hmm_vma_walk->pgmap); | |
333 | hmm_vma_walk->pgmap = NULL; | |
334 | } | |
53f5c3f4 JG |
335 | pte_unmap(ptep); |
336 | /* Fault any virtual address we were asked to fault */ | |
f8c888a3 | 337 | return hmm_vma_fault(addr, end, fault, write_fault, walk); |
53f5c3f4 JG |
338 | } |
339 | ||
da4c3c73 JG |
340 | static int hmm_vma_walk_pmd(pmd_t *pmdp, |
341 | unsigned long start, | |
342 | unsigned long end, | |
343 | struct mm_walk *walk) | |
344 | { | |
74eee180 JG |
345 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
346 | struct hmm_range *range = hmm_vma_walk->range; | |
2288a9a6 JG |
347 | uint64_t *pfns = &range->pfns[(start - range->start) >> PAGE_SHIFT]; |
348 | unsigned long npages = (end - start) >> PAGE_SHIFT; | |
349 | unsigned long addr = start; | |
350 | bool fault, write_fault; | |
da4c3c73 | 351 | pte_t *ptep; |
d08faca0 | 352 | pmd_t pmd; |
da4c3c73 | 353 | |
da4c3c73 | 354 | again: |
d08faca0 JG |
355 | pmd = READ_ONCE(*pmdp); |
356 | if (pmd_none(pmd)) | |
b7a16c7a | 357 | return hmm_vma_walk_hole(start, end, -1, walk); |
da4c3c73 | 358 | |
d08faca0 | 359 | if (thp_migration_supported() && is_pmd_migration_entry(pmd)) { |
d08faca0 JG |
360 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, |
361 | 0, &fault, &write_fault); | |
362 | if (fault || write_fault) { | |
363 | hmm_vma_walk->last = addr; | |
d2e8d551 | 364 | pmd_migration_entry_wait(walk->mm, pmdp); |
73231612 | 365 | return -EBUSY; |
d08faca0 | 366 | } |
7d082987 | 367 | return hmm_pfns_fill(start, end, range, HMM_PFN_NONE); |
2288a9a6 JG |
368 | } |
369 | ||
370 | if (!pmd_present(pmd)) { | |
371 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, 0, &fault, | |
372 | &write_fault); | |
373 | if (fault || write_fault) | |
374 | return -EFAULT; | |
d28c2c9a | 375 | return hmm_pfns_fill(start, end, range, HMM_PFN_ERROR); |
2288a9a6 | 376 | } |
da4c3c73 | 377 | |
d08faca0 | 378 | if (pmd_devmap(pmd) || pmd_trans_huge(pmd)) { |
da4c3c73 | 379 | /* |
d2e8d551 | 380 | * No need to take pmd_lock here, even if some other thread |
da4c3c73 JG |
381 | * is splitting the huge pmd we will get that event through |
382 | * mmu_notifier callback. | |
383 | * | |
d2e8d551 | 384 | * So just read pmd value and check again it's a transparent |
da4c3c73 JG |
385 | * huge or device mapping one and compute corresponding pfn |
386 | * values. | |
387 | */ | |
388 | pmd = pmd_read_atomic(pmdp); | |
389 | barrier(); | |
390 | if (!pmd_devmap(pmd) && !pmd_trans_huge(pmd)) | |
391 | goto again; | |
74eee180 | 392 | |
2288a9a6 | 393 | return hmm_vma_handle_pmd(walk, addr, end, pfns, pmd); |
da4c3c73 JG |
394 | } |
395 | ||
d08faca0 | 396 | /* |
d2e8d551 | 397 | * We have handled all the valid cases above ie either none, migration, |
d08faca0 JG |
398 | * huge or transparent huge. At this point either it is a valid pmd |
399 | * entry pointing to pte directory or it is a bad pmd that will not | |
400 | * recover. | |
401 | */ | |
2288a9a6 JG |
402 | if (pmd_bad(pmd)) { |
403 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, 0, &fault, | |
404 | &write_fault); | |
405 | if (fault || write_fault) | |
406 | return -EFAULT; | |
d28c2c9a | 407 | return hmm_pfns_fill(start, end, range, HMM_PFN_ERROR); |
2288a9a6 | 408 | } |
da4c3c73 JG |
409 | |
410 | ptep = pte_offset_map(pmdp, addr); | |
2288a9a6 | 411 | for (; addr < end; addr += PAGE_SIZE, ptep++, pfns++) { |
53f5c3f4 | 412 | int r; |
74eee180 | 413 | |
2288a9a6 | 414 | r = hmm_vma_handle_pte(walk, addr, end, pmdp, ptep, pfns); |
53f5c3f4 | 415 | if (r) { |
dfdc2207 | 416 | /* hmm_vma_handle_pte() did pte_unmap() */ |
53f5c3f4 JG |
417 | hmm_vma_walk->last = addr; |
418 | return r; | |
74eee180 | 419 | } |
da4c3c73 | 420 | } |
992de9a8 JG |
421 | if (hmm_vma_walk->pgmap) { |
422 | /* | |
423 | * We do put_dev_pagemap() here and not in hmm_vma_handle_pte() | |
424 | * so that we can leverage get_dev_pagemap() optimization which | |
425 | * will not re-take a reference on a pgmap if we already have | |
426 | * one. | |
427 | */ | |
428 | put_dev_pagemap(hmm_vma_walk->pgmap); | |
429 | hmm_vma_walk->pgmap = NULL; | |
430 | } | |
da4c3c73 JG |
431 | pte_unmap(ptep - 1); |
432 | ||
53f5c3f4 | 433 | hmm_vma_walk->last = addr; |
da4c3c73 JG |
434 | return 0; |
435 | } | |
436 | ||
f0b3c45c CH |
437 | #if defined(CONFIG_ARCH_HAS_PTE_DEVMAP) && \ |
438 | defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) | |
439 | static inline uint64_t pud_to_hmm_pfn_flags(struct hmm_range *range, pud_t pud) | |
440 | { | |
441 | if (!pud_present(pud)) | |
442 | return 0; | |
443 | return pud_write(pud) ? range->flags[HMM_PFN_VALID] | | |
444 | range->flags[HMM_PFN_WRITE] : | |
445 | range->flags[HMM_PFN_VALID]; | |
446 | } | |
447 | ||
448 | static int hmm_vma_walk_pud(pud_t *pudp, unsigned long start, unsigned long end, | |
449 | struct mm_walk *walk) | |
992de9a8 JG |
450 | { |
451 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
452 | struct hmm_range *range = hmm_vma_walk->range; | |
3afc4236 | 453 | unsigned long addr = start; |
992de9a8 | 454 | pud_t pud; |
3afc4236 SP |
455 | int ret = 0; |
456 | spinlock_t *ptl = pud_trans_huge_lock(pudp, walk->vma); | |
457 | ||
458 | if (!ptl) | |
459 | return 0; | |
460 | ||
461 | /* Normally we don't want to split the huge page */ | |
462 | walk->action = ACTION_CONTINUE; | |
992de9a8 | 463 | |
992de9a8 | 464 | pud = READ_ONCE(*pudp); |
3afc4236 | 465 | if (pud_none(pud)) { |
05fc1df9 JG |
466 | spin_unlock(ptl); |
467 | return hmm_vma_walk_hole(start, end, -1, walk); | |
3afc4236 | 468 | } |
992de9a8 JG |
469 | |
470 | if (pud_huge(pud) && pud_devmap(pud)) { | |
471 | unsigned long i, npages, pfn; | |
472 | uint64_t *pfns, cpu_flags; | |
473 | bool fault, write_fault; | |
474 | ||
3afc4236 | 475 | if (!pud_present(pud)) { |
05fc1df9 JG |
476 | spin_unlock(ptl); |
477 | return hmm_vma_walk_hole(start, end, -1, walk); | |
3afc4236 | 478 | } |
992de9a8 JG |
479 | |
480 | i = (addr - range->start) >> PAGE_SHIFT; | |
481 | npages = (end - addr) >> PAGE_SHIFT; | |
482 | pfns = &range->pfns[i]; | |
483 | ||
484 | cpu_flags = pud_to_hmm_pfn_flags(range, pud); | |
485 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, | |
486 | cpu_flags, &fault, &write_fault); | |
3afc4236 | 487 | if (fault || write_fault) { |
05fc1df9 | 488 | spin_unlock(ptl); |
f8c888a3 | 489 | return hmm_vma_fault(addr, end, fault, write_fault, |
05fc1df9 | 490 | walk); |
3afc4236 | 491 | } |
992de9a8 | 492 | |
992de9a8 JG |
493 | pfn = pud_pfn(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT); |
494 | for (i = 0; i < npages; ++i, ++pfn) { | |
495 | hmm_vma_walk->pgmap = get_dev_pagemap(pfn, | |
496 | hmm_vma_walk->pgmap); | |
3afc4236 SP |
497 | if (unlikely(!hmm_vma_walk->pgmap)) { |
498 | ret = -EBUSY; | |
499 | goto out_unlock; | |
500 | } | |
391aab11 JG |
501 | pfns[i] = hmm_device_entry_from_pfn(range, pfn) | |
502 | cpu_flags; | |
992de9a8 JG |
503 | } |
504 | if (hmm_vma_walk->pgmap) { | |
505 | put_dev_pagemap(hmm_vma_walk->pgmap); | |
506 | hmm_vma_walk->pgmap = NULL; | |
507 | } | |
508 | hmm_vma_walk->last = end; | |
3afc4236 | 509 | goto out_unlock; |
992de9a8 JG |
510 | } |
511 | ||
3afc4236 SP |
512 | /* Ask for the PUD to be split */ |
513 | walk->action = ACTION_SUBTREE; | |
992de9a8 | 514 | |
3afc4236 SP |
515 | out_unlock: |
516 | spin_unlock(ptl); | |
517 | return ret; | |
992de9a8 | 518 | } |
f0b3c45c CH |
519 | #else |
520 | #define hmm_vma_walk_pud NULL | |
521 | #endif | |
992de9a8 | 522 | |
251bbe59 | 523 | #ifdef CONFIG_HUGETLB_PAGE |
63d5066f JG |
524 | static int hmm_vma_walk_hugetlb_entry(pte_t *pte, unsigned long hmask, |
525 | unsigned long start, unsigned long end, | |
526 | struct mm_walk *walk) | |
527 | { | |
05c23af4 | 528 | unsigned long addr = start, i, pfn; |
63d5066f JG |
529 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
530 | struct hmm_range *range = hmm_vma_walk->range; | |
531 | struct vm_area_struct *vma = walk->vma; | |
63d5066f JG |
532 | uint64_t orig_pfn, cpu_flags; |
533 | bool fault, write_fault; | |
534 | spinlock_t *ptl; | |
535 | pte_t entry; | |
63d5066f | 536 | |
d2e8d551 | 537 | ptl = huge_pte_lock(hstate_vma(vma), walk->mm, pte); |
63d5066f JG |
538 | entry = huge_ptep_get(pte); |
539 | ||
7f08263d | 540 | i = (start - range->start) >> PAGE_SHIFT; |
63d5066f JG |
541 | orig_pfn = range->pfns[i]; |
542 | range->pfns[i] = range->values[HMM_PFN_NONE]; | |
543 | cpu_flags = pte_to_hmm_pfn_flags(range, entry); | |
544 | fault = write_fault = false; | |
545 | hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags, | |
546 | &fault, &write_fault); | |
547 | if (fault || write_fault) { | |
45050692 | 548 | spin_unlock(ptl); |
f8c888a3 | 549 | return hmm_vma_fault(addr, end, fault, write_fault, walk); |
63d5066f JG |
550 | } |
551 | ||
05c23af4 | 552 | pfn = pte_pfn(entry) + ((start & ~hmask) >> PAGE_SHIFT); |
7f08263d | 553 | for (; addr < end; addr += PAGE_SIZE, i++, pfn++) |
391aab11 JG |
554 | range->pfns[i] = hmm_device_entry_from_pfn(range, pfn) | |
555 | cpu_flags; | |
63d5066f | 556 | hmm_vma_walk->last = end; |
63d5066f | 557 | spin_unlock(ptl); |
45050692 | 558 | return 0; |
63d5066f | 559 | } |
251bbe59 CH |
560 | #else |
561 | #define hmm_vma_walk_hugetlb_entry NULL | |
562 | #endif /* CONFIG_HUGETLB_PAGE */ | |
63d5066f | 563 | |
d28c2c9a RC |
564 | static int hmm_vma_walk_test(unsigned long start, unsigned long end, |
565 | struct mm_walk *walk) | |
33cd47dc | 566 | { |
d28c2c9a RC |
567 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
568 | struct hmm_range *range = hmm_vma_walk->range; | |
569 | struct vm_area_struct *vma = walk->vma; | |
570 | ||
571 | /* | |
c2579c9c JG |
572 | * Skip vma ranges that don't have struct page backing them or map I/O |
573 | * devices directly. | |
574 | * | |
d28c2c9a | 575 | * If the vma does not allow read access, then assume that it does not |
c2579c9c JG |
576 | * allow write access either. HMM does not support architectures that |
577 | * allow write without read. | |
d28c2c9a | 578 | */ |
c2579c9c JG |
579 | if ((vma->vm_flags & (VM_IO | VM_PFNMAP | VM_MIXEDMAP)) || |
580 | !(vma->vm_flags & VM_READ)) { | |
d28c2c9a RC |
581 | bool fault, write_fault; |
582 | ||
583 | /* | |
584 | * Check to see if a fault is requested for any page in the | |
585 | * range. | |
586 | */ | |
587 | hmm_range_need_fault(hmm_vma_walk, range->pfns + | |
588 | ((start - range->start) >> PAGE_SHIFT), | |
589 | (end - start) >> PAGE_SHIFT, | |
590 | 0, &fault, &write_fault); | |
591 | if (fault || write_fault) | |
592 | return -EFAULT; | |
593 | ||
c2579c9c | 594 | hmm_pfns_fill(start, end, range, HMM_PFN_ERROR); |
d28c2c9a RC |
595 | hmm_vma_walk->last = end; |
596 | ||
597 | /* Skip this vma and continue processing the next vma. */ | |
598 | return 1; | |
599 | } | |
600 | ||
601 | return 0; | |
33cd47dc JG |
602 | } |
603 | ||
7b86ac33 CH |
604 | static const struct mm_walk_ops hmm_walk_ops = { |
605 | .pud_entry = hmm_vma_walk_pud, | |
606 | .pmd_entry = hmm_vma_walk_pmd, | |
607 | .pte_hole = hmm_vma_walk_hole, | |
608 | .hugetlb_entry = hmm_vma_walk_hugetlb_entry, | |
d28c2c9a | 609 | .test_walk = hmm_vma_walk_test, |
7b86ac33 CH |
610 | }; |
611 | ||
9a4903e4 CH |
612 | /** |
613 | * hmm_range_fault - try to fault some address in a virtual address range | |
614 | * @range: range being faulted | |
615 | * @flags: HMM_FAULT_* flags | |
616 | * | |
617 | * Return: the number of valid pages in range->pfns[] (from range start | |
618 | * address), which may be zero. On error one of the following status codes | |
619 | * can be returned: | |
73231612 | 620 | * |
9a4903e4 CH |
621 | * -EINVAL: Invalid arguments or mm or virtual address is in an invalid vma |
622 | * (e.g., device file vma). | |
623 | * -ENOMEM: Out of memory. | |
624 | * -EPERM: Invalid permission (e.g., asking for write and range is read | |
625 | * only). | |
9a4903e4 CH |
626 | * -EBUSY: The range has been invalidated and the caller needs to wait for |
627 | * the invalidation to finish. | |
628 | * -EFAULT: Invalid (i.e., either no valid vma or it is illegal to access | |
629 | * that range) number of valid pages in range->pfns[] (from | |
630 | * range start address). | |
74eee180 JG |
631 | * |
632 | * This is similar to a regular CPU page fault except that it will not trigger | |
73231612 JG |
633 | * any memory migration if the memory being faulted is not accessible by CPUs |
634 | * and caller does not ask for migration. | |
74eee180 | 635 | * |
ff05c0c6 JG |
636 | * On error, for one virtual address in the range, the function will mark the |
637 | * corresponding HMM pfn entry with an error flag. | |
74eee180 | 638 | */ |
9a4903e4 | 639 | long hmm_range_fault(struct hmm_range *range, unsigned int flags) |
74eee180 | 640 | { |
d28c2c9a RC |
641 | struct hmm_vma_walk hmm_vma_walk = { |
642 | .range = range, | |
643 | .last = range->start, | |
644 | .flags = flags, | |
645 | }; | |
a22dd506 | 646 | struct mm_struct *mm = range->notifier->mm; |
74eee180 JG |
647 | int ret; |
648 | ||
04ec32fb | 649 | lockdep_assert_held(&mm->mmap_sem); |
704f3f2c | 650 | |
a3e0d41c JG |
651 | do { |
652 | /* If range is no longer valid force retry. */ | |
a22dd506 JG |
653 | if (mmu_interval_check_retry(range->notifier, |
654 | range->notifier_seq)) | |
2bcbeaef | 655 | return -EBUSY; |
d28c2c9a RC |
656 | ret = walk_page_range(mm, hmm_vma_walk.last, range->end, |
657 | &hmm_walk_ops, &hmm_vma_walk); | |
658 | } while (ret == -EBUSY); | |
74eee180 | 659 | |
d28c2c9a RC |
660 | if (ret) |
661 | return ret; | |
73231612 | 662 | return (hmm_vma_walk.last - range->start) >> PAGE_SHIFT; |
74eee180 | 663 | } |
73231612 | 664 | EXPORT_SYMBOL(hmm_range_fault); |