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; | |
31 | unsigned long last; | |
9a4903e4 | 32 | unsigned int flags; |
74eee180 JG |
33 | }; |
34 | ||
d28c2c9a RC |
35 | static int hmm_pfns_fill(unsigned long addr, unsigned long end, |
36 | struct hmm_range *range, enum hmm_pfn_value_e value) | |
da4c3c73 | 37 | { |
ff05c0c6 | 38 | uint64_t *pfns = range->pfns; |
da4c3c73 JG |
39 | unsigned long i; |
40 | ||
41 | i = (addr - range->start) >> PAGE_SHIFT; | |
42 | for (; addr < end; addr += PAGE_SIZE, i++) | |
d28c2c9a | 43 | pfns[i] = range->values[value]; |
da4c3c73 JG |
44 | |
45 | return 0; | |
46 | } | |
47 | ||
5504ed29 | 48 | /* |
f8c888a3 | 49 | * hmm_vma_fault() - fault in a range lacking valid pmd or pte(s) |
d2e8d551 | 50 | * @addr: range virtual start address (inclusive) |
5504ed29 | 51 | * @end: range virtual end address (exclusive) |
2aee09d8 JG |
52 | * @fault: should we fault or not ? |
53 | * @write_fault: write fault ? | |
5504ed29 | 54 | * @walk: mm_walk structure |
f8c888a3 | 55 | * Return: -EBUSY after page fault, or page fault error |
5504ed29 JG |
56 | * |
57 | * This function will be called whenever pmd_none() or pte_none() returns true, | |
58 | * or whenever there is no page directory covering the virtual address range. | |
59 | */ | |
f8c888a3 | 60 | static int hmm_vma_fault(unsigned long addr, unsigned long end, |
2aee09d8 JG |
61 | bool fault, bool write_fault, |
62 | struct mm_walk *walk) | |
da4c3c73 | 63 | { |
74eee180 JG |
64 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
65 | struct hmm_range *range = hmm_vma_walk->range; | |
5a0c38d3 | 66 | struct vm_area_struct *vma = walk->vma; |
ff05c0c6 | 67 | uint64_t *pfns = range->pfns; |
f8c888a3 | 68 | unsigned long i = (addr - range->start) >> PAGE_SHIFT; |
5a0c38d3 | 69 | unsigned int fault_flags = FAULT_FLAG_REMOTE; |
da4c3c73 | 70 | |
f8c888a3 | 71 | WARN_ON_ONCE(!fault && !write_fault); |
74eee180 | 72 | hmm_vma_walk->last = addr; |
63d5066f | 73 | |
5a0c38d3 CH |
74 | if (!vma) |
75 | goto out_error; | |
da4c3c73 | 76 | |
5a0c38d3 CH |
77 | if (write_fault) { |
78 | if (!(vma->vm_flags & VM_WRITE)) | |
79 | return -EPERM; | |
80 | fault_flags |= FAULT_FLAG_WRITE; | |
74eee180 JG |
81 | } |
82 | ||
5a0c38d3 CH |
83 | for (; addr < end; addr += PAGE_SIZE, i++) |
84 | if (handle_mm_fault(vma, addr, fault_flags) & VM_FAULT_ERROR) | |
85 | goto out_error; | |
86 | ||
f8c888a3 | 87 | return -EBUSY; |
5a0c38d3 CH |
88 | |
89 | out_error: | |
90 | pfns[i] = range->values[HMM_PFN_ERROR]; | |
91 | return -EFAULT; | |
2aee09d8 JG |
92 | } |
93 | ||
94 | static inline void hmm_pte_need_fault(const struct hmm_vma_walk *hmm_vma_walk, | |
95 | uint64_t pfns, uint64_t cpu_flags, | |
96 | bool *fault, bool *write_fault) | |
97 | { | |
f88a1e90 JG |
98 | struct hmm_range *range = hmm_vma_walk->range; |
99 | ||
d45d464b | 100 | if (hmm_vma_walk->flags & HMM_FAULT_SNAPSHOT) |
2aee09d8 JG |
101 | return; |
102 | ||
023a019a JG |
103 | /* |
104 | * So we not only consider the individual per page request we also | |
105 | * consider the default flags requested for the range. The API can | |
d2e8d551 RC |
106 | * be used 2 ways. The first one where the HMM user coalesces |
107 | * multiple page faults into one request and sets flags per pfn for | |
108 | * those faults. The second one where the HMM user wants to pre- | |
023a019a JG |
109 | * fault a range with specific flags. For the latter one it is a |
110 | * waste to have the user pre-fill the pfn arrays with a default | |
111 | * flags value. | |
112 | */ | |
113 | pfns = (pfns & range->pfn_flags_mask) | range->default_flags; | |
114 | ||
2aee09d8 | 115 | /* We aren't ask to do anything ... */ |
f88a1e90 | 116 | if (!(pfns & range->flags[HMM_PFN_VALID])) |
2aee09d8 | 117 | return; |
f88a1e90 JG |
118 | |
119 | /* If CPU page table is not valid then we need to fault */ | |
120 | *fault = !(cpu_flags & range->flags[HMM_PFN_VALID]); | |
121 | /* Need to write fault ? */ | |
122 | if ((pfns & range->flags[HMM_PFN_WRITE]) && | |
123 | !(cpu_flags & range->flags[HMM_PFN_WRITE])) { | |
124 | *write_fault = true; | |
2aee09d8 JG |
125 | *fault = true; |
126 | } | |
127 | } | |
128 | ||
129 | static void hmm_range_need_fault(const struct hmm_vma_walk *hmm_vma_walk, | |
130 | const uint64_t *pfns, unsigned long npages, | |
131 | uint64_t cpu_flags, bool *fault, | |
132 | bool *write_fault) | |
133 | { | |
134 | unsigned long i; | |
135 | ||
d45d464b | 136 | if (hmm_vma_walk->flags & HMM_FAULT_SNAPSHOT) { |
2aee09d8 JG |
137 | *fault = *write_fault = false; |
138 | return; | |
139 | } | |
140 | ||
a3e0d41c | 141 | *fault = *write_fault = false; |
2aee09d8 JG |
142 | for (i = 0; i < npages; ++i) { |
143 | hmm_pte_need_fault(hmm_vma_walk, pfns[i], cpu_flags, | |
144 | fault, write_fault); | |
a3e0d41c | 145 | if ((*write_fault)) |
2aee09d8 JG |
146 | return; |
147 | } | |
148 | } | |
149 | ||
150 | static int hmm_vma_walk_hole(unsigned long addr, unsigned long end, | |
b7a16c7a | 151 | __always_unused int depth, struct mm_walk *walk) |
2aee09d8 JG |
152 | { |
153 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
154 | struct hmm_range *range = hmm_vma_walk->range; | |
155 | bool fault, write_fault; | |
156 | unsigned long i, npages; | |
157 | uint64_t *pfns; | |
158 | ||
159 | i = (addr - range->start) >> PAGE_SHIFT; | |
160 | npages = (end - addr) >> PAGE_SHIFT; | |
161 | pfns = &range->pfns[i]; | |
162 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, | |
163 | 0, &fault, &write_fault); | |
f8c888a3 CH |
164 | if (fault || write_fault) |
165 | return hmm_vma_fault(addr, end, fault, write_fault, walk); | |
166 | hmm_vma_walk->last = addr; | |
167 | return hmm_pfns_fill(addr, end, range, HMM_PFN_NONE); | |
2aee09d8 JG |
168 | } |
169 | ||
f88a1e90 | 170 | static inline uint64_t pmd_to_hmm_pfn_flags(struct hmm_range *range, pmd_t pmd) |
2aee09d8 JG |
171 | { |
172 | if (pmd_protnone(pmd)) | |
173 | return 0; | |
f88a1e90 JG |
174 | return pmd_write(pmd) ? range->flags[HMM_PFN_VALID] | |
175 | range->flags[HMM_PFN_WRITE] : | |
176 | range->flags[HMM_PFN_VALID]; | |
da4c3c73 JG |
177 | } |
178 | ||
992de9a8 | 179 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
9d3973d6 CH |
180 | static int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr, |
181 | unsigned long end, uint64_t *pfns, pmd_t pmd) | |
182 | { | |
53f5c3f4 | 183 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
f88a1e90 | 184 | struct hmm_range *range = hmm_vma_walk->range; |
2aee09d8 | 185 | unsigned long pfn, npages, i; |
2aee09d8 | 186 | bool fault, write_fault; |
f88a1e90 | 187 | uint64_t cpu_flags; |
53f5c3f4 | 188 | |
2aee09d8 | 189 | npages = (end - addr) >> PAGE_SHIFT; |
f88a1e90 | 190 | cpu_flags = pmd_to_hmm_pfn_flags(range, pmd); |
2aee09d8 JG |
191 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, cpu_flags, |
192 | &fault, &write_fault); | |
53f5c3f4 | 193 | |
24cee8ab | 194 | if (fault || write_fault) |
f8c888a3 | 195 | return hmm_vma_fault(addr, end, fault, write_fault, walk); |
53f5c3f4 | 196 | |
309f9a4f | 197 | pfn = pmd_pfn(pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT); |
068354ad | 198 | for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++) |
391aab11 | 199 | pfns[i] = hmm_device_entry_from_pfn(range, pfn) | cpu_flags; |
53f5c3f4 JG |
200 | hmm_vma_walk->last = end; |
201 | return 0; | |
202 | } | |
9d3973d6 CH |
203 | #else /* CONFIG_TRANSPARENT_HUGEPAGE */ |
204 | /* stub to allow the code below to compile */ | |
205 | int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr, | |
206 | unsigned long end, uint64_t *pfns, pmd_t pmd); | |
207 | #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ | |
53f5c3f4 | 208 | |
08ddddda CH |
209 | static inline bool hmm_is_device_private_entry(struct hmm_range *range, |
210 | swp_entry_t entry) | |
211 | { | |
212 | return is_device_private_entry(entry) && | |
213 | device_private_entry_to_page(entry)->pgmap->owner == | |
214 | range->dev_private_owner; | |
215 | } | |
216 | ||
f88a1e90 | 217 | static inline uint64_t pte_to_hmm_pfn_flags(struct hmm_range *range, pte_t pte) |
2aee09d8 | 218 | { |
789c2af8 | 219 | if (pte_none(pte) || !pte_present(pte) || pte_protnone(pte)) |
2aee09d8 | 220 | return 0; |
f88a1e90 JG |
221 | return pte_write(pte) ? range->flags[HMM_PFN_VALID] | |
222 | range->flags[HMM_PFN_WRITE] : | |
223 | range->flags[HMM_PFN_VALID]; | |
2aee09d8 JG |
224 | } |
225 | ||
53f5c3f4 JG |
226 | static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr, |
227 | unsigned long end, pmd_t *pmdp, pte_t *ptep, | |
228 | uint64_t *pfn) | |
229 | { | |
230 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
f88a1e90 | 231 | struct hmm_range *range = hmm_vma_walk->range; |
2aee09d8 JG |
232 | bool fault, write_fault; |
233 | uint64_t cpu_flags; | |
53f5c3f4 | 234 | pte_t pte = *ptep; |
f88a1e90 | 235 | uint64_t orig_pfn = *pfn; |
53f5c3f4 | 236 | |
f88a1e90 | 237 | *pfn = range->values[HMM_PFN_NONE]; |
73231612 | 238 | fault = write_fault = false; |
53f5c3f4 JG |
239 | |
240 | if (pte_none(pte)) { | |
73231612 JG |
241 | hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0, |
242 | &fault, &write_fault); | |
2aee09d8 | 243 | if (fault || write_fault) |
53f5c3f4 JG |
244 | goto fault; |
245 | return 0; | |
246 | } | |
247 | ||
248 | if (!pte_present(pte)) { | |
249 | swp_entry_t entry = pte_to_swp_entry(pte); | |
250 | ||
53f5c3f4 | 251 | /* |
17ffdc48 CH |
252 | * Never fault in device private pages pages, but just report |
253 | * the PFN even if not present. | |
53f5c3f4 | 254 | */ |
08ddddda | 255 | if (hmm_is_device_private_entry(range, entry)) { |
391aab11 JG |
256 | *pfn = hmm_device_entry_from_pfn(range, |
257 | swp_offset(entry)); | |
17ffdc48 CH |
258 | *pfn |= range->flags[HMM_PFN_VALID]; |
259 | if (is_write_device_private_entry(entry)) | |
260 | *pfn |= range->flags[HMM_PFN_WRITE]; | |
53f5c3f4 JG |
261 | return 0; |
262 | } | |
263 | ||
76612d6c JG |
264 | hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0, &fault, |
265 | &write_fault); | |
266 | if (!fault && !write_fault) | |
53f5c3f4 | 267 | return 0; |
76612d6c JG |
268 | |
269 | if (!non_swap_entry(entry)) | |
270 | goto fault; | |
271 | ||
272 | if (is_migration_entry(entry)) { | |
273 | pte_unmap(ptep); | |
274 | hmm_vma_walk->last = addr; | |
275 | migration_entry_wait(walk->mm, pmdp, addr); | |
276 | return -EBUSY; | |
53f5c3f4 JG |
277 | } |
278 | ||
279 | /* Report error for everything else */ | |
dfdc2207 | 280 | pte_unmap(ptep); |
f88a1e90 | 281 | *pfn = range->values[HMM_PFN_ERROR]; |
53f5c3f4 JG |
282 | return -EFAULT; |
283 | } | |
284 | ||
76612d6c JG |
285 | cpu_flags = pte_to_hmm_pfn_flags(range, pte); |
286 | hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags, &fault, | |
287 | &write_fault); | |
2aee09d8 | 288 | if (fault || write_fault) |
53f5c3f4 JG |
289 | goto fault; |
290 | ||
40550627 JG |
291 | /* |
292 | * Since each architecture defines a struct page for the zero page, just | |
293 | * fall through and treat it like a normal page. | |
294 | */ | |
295 | if (pte_special(pte) && !is_zero_pfn(pte_pfn(pte))) { | |
296 | hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0, &fault, | |
297 | &write_fault); | |
298 | if (fault || write_fault) { | |
dfdc2207 | 299 | pte_unmap(ptep); |
ac541f25 RC |
300 | return -EFAULT; |
301 | } | |
40550627 JG |
302 | *pfn = range->values[HMM_PFN_SPECIAL]; |
303 | return 0; | |
992de9a8 JG |
304 | } |
305 | ||
391aab11 | 306 | *pfn = hmm_device_entry_from_pfn(range, pte_pfn(pte)) | cpu_flags; |
53f5c3f4 JG |
307 | return 0; |
308 | ||
309 | fault: | |
310 | pte_unmap(ptep); | |
311 | /* Fault any virtual address we were asked to fault */ | |
f8c888a3 | 312 | return hmm_vma_fault(addr, end, fault, write_fault, walk); |
53f5c3f4 JG |
313 | } |
314 | ||
da4c3c73 JG |
315 | static int hmm_vma_walk_pmd(pmd_t *pmdp, |
316 | unsigned long start, | |
317 | unsigned long end, | |
318 | struct mm_walk *walk) | |
319 | { | |
74eee180 JG |
320 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
321 | struct hmm_range *range = hmm_vma_walk->range; | |
2288a9a6 JG |
322 | uint64_t *pfns = &range->pfns[(start - range->start) >> PAGE_SHIFT]; |
323 | unsigned long npages = (end - start) >> PAGE_SHIFT; | |
324 | unsigned long addr = start; | |
325 | bool fault, write_fault; | |
da4c3c73 | 326 | pte_t *ptep; |
d08faca0 | 327 | pmd_t pmd; |
da4c3c73 | 328 | |
da4c3c73 | 329 | again: |
d08faca0 JG |
330 | pmd = READ_ONCE(*pmdp); |
331 | if (pmd_none(pmd)) | |
b7a16c7a | 332 | return hmm_vma_walk_hole(start, end, -1, walk); |
da4c3c73 | 333 | |
d08faca0 | 334 | if (thp_migration_supported() && is_pmd_migration_entry(pmd)) { |
d08faca0 JG |
335 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, |
336 | 0, &fault, &write_fault); | |
337 | if (fault || write_fault) { | |
338 | hmm_vma_walk->last = addr; | |
d2e8d551 | 339 | pmd_migration_entry_wait(walk->mm, pmdp); |
73231612 | 340 | return -EBUSY; |
d08faca0 | 341 | } |
7d082987 | 342 | return hmm_pfns_fill(start, end, range, HMM_PFN_NONE); |
2288a9a6 JG |
343 | } |
344 | ||
345 | if (!pmd_present(pmd)) { | |
346 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, 0, &fault, | |
347 | &write_fault); | |
348 | if (fault || write_fault) | |
349 | return -EFAULT; | |
d28c2c9a | 350 | return hmm_pfns_fill(start, end, range, HMM_PFN_ERROR); |
2288a9a6 | 351 | } |
da4c3c73 | 352 | |
d08faca0 | 353 | if (pmd_devmap(pmd) || pmd_trans_huge(pmd)) { |
da4c3c73 | 354 | /* |
d2e8d551 | 355 | * No need to take pmd_lock here, even if some other thread |
da4c3c73 JG |
356 | * is splitting the huge pmd we will get that event through |
357 | * mmu_notifier callback. | |
358 | * | |
d2e8d551 | 359 | * So just read pmd value and check again it's a transparent |
da4c3c73 JG |
360 | * huge or device mapping one and compute corresponding pfn |
361 | * values. | |
362 | */ | |
363 | pmd = pmd_read_atomic(pmdp); | |
364 | barrier(); | |
365 | if (!pmd_devmap(pmd) && !pmd_trans_huge(pmd)) | |
366 | goto again; | |
74eee180 | 367 | |
2288a9a6 | 368 | return hmm_vma_handle_pmd(walk, addr, end, pfns, pmd); |
da4c3c73 JG |
369 | } |
370 | ||
d08faca0 | 371 | /* |
d2e8d551 | 372 | * We have handled all the valid cases above ie either none, migration, |
d08faca0 JG |
373 | * huge or transparent huge. At this point either it is a valid pmd |
374 | * entry pointing to pte directory or it is a bad pmd that will not | |
375 | * recover. | |
376 | */ | |
2288a9a6 JG |
377 | if (pmd_bad(pmd)) { |
378 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, 0, &fault, | |
379 | &write_fault); | |
380 | if (fault || write_fault) | |
381 | return -EFAULT; | |
d28c2c9a | 382 | return hmm_pfns_fill(start, end, range, HMM_PFN_ERROR); |
2288a9a6 | 383 | } |
da4c3c73 JG |
384 | |
385 | ptep = pte_offset_map(pmdp, addr); | |
2288a9a6 | 386 | for (; addr < end; addr += PAGE_SIZE, ptep++, pfns++) { |
53f5c3f4 | 387 | int r; |
74eee180 | 388 | |
2288a9a6 | 389 | r = hmm_vma_handle_pte(walk, addr, end, pmdp, ptep, pfns); |
53f5c3f4 | 390 | if (r) { |
dfdc2207 | 391 | /* hmm_vma_handle_pte() did pte_unmap() */ |
53f5c3f4 JG |
392 | hmm_vma_walk->last = addr; |
393 | return r; | |
74eee180 | 394 | } |
da4c3c73 JG |
395 | } |
396 | pte_unmap(ptep - 1); | |
397 | ||
53f5c3f4 | 398 | hmm_vma_walk->last = addr; |
da4c3c73 JG |
399 | return 0; |
400 | } | |
401 | ||
f0b3c45c CH |
402 | #if defined(CONFIG_ARCH_HAS_PTE_DEVMAP) && \ |
403 | defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) | |
404 | static inline uint64_t pud_to_hmm_pfn_flags(struct hmm_range *range, pud_t pud) | |
405 | { | |
406 | if (!pud_present(pud)) | |
407 | return 0; | |
408 | return pud_write(pud) ? range->flags[HMM_PFN_VALID] | | |
409 | range->flags[HMM_PFN_WRITE] : | |
410 | range->flags[HMM_PFN_VALID]; | |
411 | } | |
412 | ||
413 | static int hmm_vma_walk_pud(pud_t *pudp, unsigned long start, unsigned long end, | |
414 | struct mm_walk *walk) | |
992de9a8 JG |
415 | { |
416 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
417 | struct hmm_range *range = hmm_vma_walk->range; | |
3afc4236 | 418 | unsigned long addr = start; |
992de9a8 | 419 | pud_t pud; |
3afc4236 SP |
420 | int ret = 0; |
421 | spinlock_t *ptl = pud_trans_huge_lock(pudp, walk->vma); | |
422 | ||
423 | if (!ptl) | |
424 | return 0; | |
425 | ||
426 | /* Normally we don't want to split the huge page */ | |
427 | walk->action = ACTION_CONTINUE; | |
992de9a8 | 428 | |
992de9a8 | 429 | pud = READ_ONCE(*pudp); |
3afc4236 | 430 | if (pud_none(pud)) { |
05fc1df9 JG |
431 | spin_unlock(ptl); |
432 | return hmm_vma_walk_hole(start, end, -1, walk); | |
3afc4236 | 433 | } |
992de9a8 JG |
434 | |
435 | if (pud_huge(pud) && pud_devmap(pud)) { | |
436 | unsigned long i, npages, pfn; | |
437 | uint64_t *pfns, cpu_flags; | |
438 | bool fault, write_fault; | |
439 | ||
3afc4236 | 440 | if (!pud_present(pud)) { |
05fc1df9 JG |
441 | spin_unlock(ptl); |
442 | return hmm_vma_walk_hole(start, end, -1, walk); | |
3afc4236 | 443 | } |
992de9a8 JG |
444 | |
445 | i = (addr - range->start) >> PAGE_SHIFT; | |
446 | npages = (end - addr) >> PAGE_SHIFT; | |
447 | pfns = &range->pfns[i]; | |
448 | ||
449 | cpu_flags = pud_to_hmm_pfn_flags(range, pud); | |
450 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, | |
451 | cpu_flags, &fault, &write_fault); | |
3afc4236 | 452 | if (fault || write_fault) { |
05fc1df9 | 453 | spin_unlock(ptl); |
f8c888a3 | 454 | return hmm_vma_fault(addr, end, fault, write_fault, |
05fc1df9 | 455 | walk); |
3afc4236 | 456 | } |
992de9a8 | 457 | |
992de9a8 | 458 | pfn = pud_pfn(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT); |
068354ad | 459 | for (i = 0; i < npages; ++i, ++pfn) |
391aab11 JG |
460 | pfns[i] = hmm_device_entry_from_pfn(range, pfn) | |
461 | cpu_flags; | |
992de9a8 | 462 | hmm_vma_walk->last = end; |
3afc4236 | 463 | goto out_unlock; |
992de9a8 JG |
464 | } |
465 | ||
3afc4236 SP |
466 | /* Ask for the PUD to be split */ |
467 | walk->action = ACTION_SUBTREE; | |
992de9a8 | 468 | |
3afc4236 SP |
469 | out_unlock: |
470 | spin_unlock(ptl); | |
471 | return ret; | |
992de9a8 | 472 | } |
f0b3c45c CH |
473 | #else |
474 | #define hmm_vma_walk_pud NULL | |
475 | #endif | |
992de9a8 | 476 | |
251bbe59 | 477 | #ifdef CONFIG_HUGETLB_PAGE |
63d5066f JG |
478 | static int hmm_vma_walk_hugetlb_entry(pte_t *pte, unsigned long hmask, |
479 | unsigned long start, unsigned long end, | |
480 | struct mm_walk *walk) | |
481 | { | |
05c23af4 | 482 | unsigned long addr = start, i, pfn; |
63d5066f JG |
483 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
484 | struct hmm_range *range = hmm_vma_walk->range; | |
485 | struct vm_area_struct *vma = walk->vma; | |
63d5066f JG |
486 | uint64_t orig_pfn, cpu_flags; |
487 | bool fault, write_fault; | |
488 | spinlock_t *ptl; | |
489 | pte_t entry; | |
63d5066f | 490 | |
d2e8d551 | 491 | ptl = huge_pte_lock(hstate_vma(vma), walk->mm, pte); |
63d5066f JG |
492 | entry = huge_ptep_get(pte); |
493 | ||
7f08263d | 494 | i = (start - range->start) >> PAGE_SHIFT; |
63d5066f JG |
495 | orig_pfn = range->pfns[i]; |
496 | range->pfns[i] = range->values[HMM_PFN_NONE]; | |
497 | cpu_flags = pte_to_hmm_pfn_flags(range, entry); | |
498 | fault = write_fault = false; | |
499 | hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags, | |
500 | &fault, &write_fault); | |
501 | if (fault || write_fault) { | |
45050692 | 502 | spin_unlock(ptl); |
f8c888a3 | 503 | return hmm_vma_fault(addr, end, fault, write_fault, walk); |
63d5066f JG |
504 | } |
505 | ||
05c23af4 | 506 | pfn = pte_pfn(entry) + ((start & ~hmask) >> PAGE_SHIFT); |
7f08263d | 507 | for (; addr < end; addr += PAGE_SIZE, i++, pfn++) |
391aab11 JG |
508 | range->pfns[i] = hmm_device_entry_from_pfn(range, pfn) | |
509 | cpu_flags; | |
63d5066f | 510 | hmm_vma_walk->last = end; |
63d5066f | 511 | spin_unlock(ptl); |
45050692 | 512 | return 0; |
63d5066f | 513 | } |
251bbe59 CH |
514 | #else |
515 | #define hmm_vma_walk_hugetlb_entry NULL | |
516 | #endif /* CONFIG_HUGETLB_PAGE */ | |
63d5066f | 517 | |
d28c2c9a RC |
518 | static int hmm_vma_walk_test(unsigned long start, unsigned long end, |
519 | struct mm_walk *walk) | |
33cd47dc | 520 | { |
d28c2c9a RC |
521 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
522 | struct hmm_range *range = hmm_vma_walk->range; | |
523 | struct vm_area_struct *vma = walk->vma; | |
524 | ||
525 | /* | |
c2579c9c JG |
526 | * Skip vma ranges that don't have struct page backing them or map I/O |
527 | * devices directly. | |
528 | * | |
d28c2c9a | 529 | * If the vma does not allow read access, then assume that it does not |
c2579c9c JG |
530 | * allow write access either. HMM does not support architectures that |
531 | * allow write without read. | |
d28c2c9a | 532 | */ |
c2579c9c JG |
533 | if ((vma->vm_flags & (VM_IO | VM_PFNMAP | VM_MIXEDMAP)) || |
534 | !(vma->vm_flags & VM_READ)) { | |
d28c2c9a RC |
535 | bool fault, write_fault; |
536 | ||
537 | /* | |
538 | * Check to see if a fault is requested for any page in the | |
539 | * range. | |
540 | */ | |
541 | hmm_range_need_fault(hmm_vma_walk, range->pfns + | |
542 | ((start - range->start) >> PAGE_SHIFT), | |
543 | (end - start) >> PAGE_SHIFT, | |
544 | 0, &fault, &write_fault); | |
545 | if (fault || write_fault) | |
546 | return -EFAULT; | |
547 | ||
c2579c9c | 548 | hmm_pfns_fill(start, end, range, HMM_PFN_ERROR); |
d28c2c9a RC |
549 | hmm_vma_walk->last = end; |
550 | ||
551 | /* Skip this vma and continue processing the next vma. */ | |
552 | return 1; | |
553 | } | |
554 | ||
555 | return 0; | |
33cd47dc JG |
556 | } |
557 | ||
7b86ac33 CH |
558 | static const struct mm_walk_ops hmm_walk_ops = { |
559 | .pud_entry = hmm_vma_walk_pud, | |
560 | .pmd_entry = hmm_vma_walk_pmd, | |
561 | .pte_hole = hmm_vma_walk_hole, | |
562 | .hugetlb_entry = hmm_vma_walk_hugetlb_entry, | |
d28c2c9a | 563 | .test_walk = hmm_vma_walk_test, |
7b86ac33 CH |
564 | }; |
565 | ||
9a4903e4 CH |
566 | /** |
567 | * hmm_range_fault - try to fault some address in a virtual address range | |
568 | * @range: range being faulted | |
569 | * @flags: HMM_FAULT_* flags | |
570 | * | |
571 | * Return: the number of valid pages in range->pfns[] (from range start | |
572 | * address), which may be zero. On error one of the following status codes | |
573 | * can be returned: | |
73231612 | 574 | * |
9a4903e4 CH |
575 | * -EINVAL: Invalid arguments or mm or virtual address is in an invalid vma |
576 | * (e.g., device file vma). | |
577 | * -ENOMEM: Out of memory. | |
578 | * -EPERM: Invalid permission (e.g., asking for write and range is read | |
579 | * only). | |
9a4903e4 CH |
580 | * -EBUSY: The range has been invalidated and the caller needs to wait for |
581 | * the invalidation to finish. | |
582 | * -EFAULT: Invalid (i.e., either no valid vma or it is illegal to access | |
583 | * that range) number of valid pages in range->pfns[] (from | |
584 | * range start address). | |
74eee180 JG |
585 | * |
586 | * This is similar to a regular CPU page fault except that it will not trigger | |
73231612 JG |
587 | * any memory migration if the memory being faulted is not accessible by CPUs |
588 | * and caller does not ask for migration. | |
74eee180 | 589 | * |
ff05c0c6 JG |
590 | * On error, for one virtual address in the range, the function will mark the |
591 | * corresponding HMM pfn entry with an error flag. | |
74eee180 | 592 | */ |
9a4903e4 | 593 | long hmm_range_fault(struct hmm_range *range, unsigned int flags) |
74eee180 | 594 | { |
d28c2c9a RC |
595 | struct hmm_vma_walk hmm_vma_walk = { |
596 | .range = range, | |
597 | .last = range->start, | |
598 | .flags = flags, | |
599 | }; | |
a22dd506 | 600 | struct mm_struct *mm = range->notifier->mm; |
74eee180 JG |
601 | int ret; |
602 | ||
04ec32fb | 603 | lockdep_assert_held(&mm->mmap_sem); |
704f3f2c | 604 | |
a3e0d41c JG |
605 | do { |
606 | /* If range is no longer valid force retry. */ | |
a22dd506 JG |
607 | if (mmu_interval_check_retry(range->notifier, |
608 | range->notifier_seq)) | |
2bcbeaef | 609 | return -EBUSY; |
d28c2c9a RC |
610 | ret = walk_page_range(mm, hmm_vma_walk.last, range->end, |
611 | &hmm_walk_ops, &hmm_vma_walk); | |
612 | } while (ret == -EBUSY); | |
74eee180 | 613 | |
d28c2c9a RC |
614 | if (ret) |
615 | return ret; | |
73231612 | 616 | return (hmm_vma_walk.last - range->start) >> PAGE_SHIFT; |
74eee180 | 617 | } |
73231612 | 618 | EXPORT_SYMBOL(hmm_range_fault); |