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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 | ||
a3eb13c1 JG |
35 | enum { |
36 | HMM_NEED_FAULT = 1 << 0, | |
37 | HMM_NEED_WRITE_FAULT = 1 << 1, | |
38 | HMM_NEED_ALL_BITS = HMM_NEED_FAULT | HMM_NEED_WRITE_FAULT, | |
39 | }; | |
40 | ||
d28c2c9a RC |
41 | static int hmm_pfns_fill(unsigned long addr, unsigned long end, |
42 | struct hmm_range *range, enum hmm_pfn_value_e value) | |
da4c3c73 | 43 | { |
ff05c0c6 | 44 | uint64_t *pfns = range->pfns; |
da4c3c73 JG |
45 | unsigned long i; |
46 | ||
47 | i = (addr - range->start) >> PAGE_SHIFT; | |
48 | for (; addr < end; addr += PAGE_SIZE, i++) | |
d28c2c9a | 49 | pfns[i] = range->values[value]; |
da4c3c73 JG |
50 | |
51 | return 0; | |
52 | } | |
53 | ||
5504ed29 | 54 | /* |
f8c888a3 | 55 | * hmm_vma_fault() - fault in a range lacking valid pmd or pte(s) |
d2e8d551 | 56 | * @addr: range virtual start address (inclusive) |
5504ed29 | 57 | * @end: range virtual end address (exclusive) |
a3eb13c1 | 58 | * @required_fault: HMM_NEED_* flags |
5504ed29 | 59 | * @walk: mm_walk structure |
f8c888a3 | 60 | * Return: -EBUSY after page fault, or page fault error |
5504ed29 JG |
61 | * |
62 | * This function will be called whenever pmd_none() or pte_none() returns true, | |
63 | * or whenever there is no page directory covering the virtual address range. | |
64 | */ | |
f8c888a3 | 65 | static int hmm_vma_fault(unsigned long addr, unsigned long end, |
a3eb13c1 | 66 | unsigned int required_fault, struct mm_walk *walk) |
da4c3c73 | 67 | { |
74eee180 JG |
68 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
69 | struct hmm_range *range = hmm_vma_walk->range; | |
5a0c38d3 | 70 | struct vm_area_struct *vma = walk->vma; |
ff05c0c6 | 71 | uint64_t *pfns = range->pfns; |
f8c888a3 | 72 | unsigned long i = (addr - range->start) >> PAGE_SHIFT; |
5a0c38d3 | 73 | unsigned int fault_flags = FAULT_FLAG_REMOTE; |
da4c3c73 | 74 | |
a3eb13c1 | 75 | WARN_ON_ONCE(!required_fault); |
74eee180 | 76 | hmm_vma_walk->last = addr; |
63d5066f | 77 | |
5a0c38d3 CH |
78 | if (!vma) |
79 | goto out_error; | |
da4c3c73 | 80 | |
a3eb13c1 | 81 | if (required_fault & HMM_NEED_WRITE_FAULT) { |
5a0c38d3 CH |
82 | if (!(vma->vm_flags & VM_WRITE)) |
83 | return -EPERM; | |
84 | fault_flags |= FAULT_FLAG_WRITE; | |
74eee180 JG |
85 | } |
86 | ||
5a0c38d3 CH |
87 | for (; addr < end; addr += PAGE_SIZE, i++) |
88 | if (handle_mm_fault(vma, addr, fault_flags) & VM_FAULT_ERROR) | |
89 | goto out_error; | |
90 | ||
f8c888a3 | 91 | return -EBUSY; |
5a0c38d3 CH |
92 | |
93 | out_error: | |
94 | pfns[i] = range->values[HMM_PFN_ERROR]; | |
95 | return -EFAULT; | |
2aee09d8 JG |
96 | } |
97 | ||
a3eb13c1 JG |
98 | static unsigned int hmm_pte_need_fault(const struct hmm_vma_walk *hmm_vma_walk, |
99 | uint64_t pfns, uint64_t cpu_flags) | |
2aee09d8 | 100 | { |
f88a1e90 JG |
101 | struct hmm_range *range = hmm_vma_walk->range; |
102 | ||
d45d464b | 103 | if (hmm_vma_walk->flags & HMM_FAULT_SNAPSHOT) |
a3eb13c1 | 104 | return 0; |
2aee09d8 | 105 | |
023a019a JG |
106 | /* |
107 | * So we not only consider the individual per page request we also | |
108 | * consider the default flags requested for the range. The API can | |
d2e8d551 RC |
109 | * be used 2 ways. The first one where the HMM user coalesces |
110 | * multiple page faults into one request and sets flags per pfn for | |
111 | * those faults. The second one where the HMM user wants to pre- | |
023a019a JG |
112 | * fault a range with specific flags. For the latter one it is a |
113 | * waste to have the user pre-fill the pfn arrays with a default | |
114 | * flags value. | |
115 | */ | |
116 | pfns = (pfns & range->pfn_flags_mask) | range->default_flags; | |
117 | ||
2aee09d8 | 118 | /* We aren't ask to do anything ... */ |
f88a1e90 | 119 | if (!(pfns & range->flags[HMM_PFN_VALID])) |
a3eb13c1 | 120 | return 0; |
f88a1e90 | 121 | |
f88a1e90 JG |
122 | /* Need to write fault ? */ |
123 | if ((pfns & range->flags[HMM_PFN_WRITE]) && | |
a3eb13c1 JG |
124 | !(cpu_flags & range->flags[HMM_PFN_WRITE])) |
125 | return HMM_NEED_FAULT | HMM_NEED_WRITE_FAULT; | |
126 | ||
127 | /* If CPU page table is not valid then we need to fault */ | |
128 | if (!(cpu_flags & range->flags[HMM_PFN_VALID])) | |
129 | return HMM_NEED_FAULT; | |
130 | return 0; | |
2aee09d8 JG |
131 | } |
132 | ||
a3eb13c1 JG |
133 | static unsigned int |
134 | hmm_range_need_fault(const struct hmm_vma_walk *hmm_vma_walk, | |
135 | const uint64_t *pfns, unsigned long npages, | |
136 | uint64_t cpu_flags) | |
2aee09d8 | 137 | { |
a3eb13c1 | 138 | unsigned int required_fault = 0; |
2aee09d8 JG |
139 | unsigned long i; |
140 | ||
a3eb13c1 JG |
141 | if (hmm_vma_walk->flags & HMM_FAULT_SNAPSHOT) |
142 | return 0; | |
2aee09d8 JG |
143 | |
144 | for (i = 0; i < npages; ++i) { | |
a3eb13c1 JG |
145 | required_fault |= |
146 | hmm_pte_need_fault(hmm_vma_walk, pfns[i], cpu_flags); | |
147 | if (required_fault == HMM_NEED_ALL_BITS) | |
148 | return required_fault; | |
2aee09d8 | 149 | } |
a3eb13c1 | 150 | return required_fault; |
2aee09d8 JG |
151 | } |
152 | ||
153 | static int hmm_vma_walk_hole(unsigned long addr, unsigned long end, | |
b7a16c7a | 154 | __always_unused int depth, struct mm_walk *walk) |
2aee09d8 JG |
155 | { |
156 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
157 | struct hmm_range *range = hmm_vma_walk->range; | |
a3eb13c1 | 158 | unsigned int required_fault; |
2aee09d8 JG |
159 | unsigned long i, npages; |
160 | uint64_t *pfns; | |
161 | ||
162 | i = (addr - range->start) >> PAGE_SHIFT; | |
163 | npages = (end - addr) >> PAGE_SHIFT; | |
164 | pfns = &range->pfns[i]; | |
a3eb13c1 JG |
165 | required_fault = hmm_range_need_fault(hmm_vma_walk, pfns, npages, 0); |
166 | if (required_fault) | |
167 | return hmm_vma_fault(addr, end, required_fault, walk); | |
f8c888a3 CH |
168 | hmm_vma_walk->last = addr; |
169 | return hmm_pfns_fill(addr, end, range, HMM_PFN_NONE); | |
2aee09d8 JG |
170 | } |
171 | ||
f88a1e90 | 172 | static inline uint64_t pmd_to_hmm_pfn_flags(struct hmm_range *range, pmd_t pmd) |
2aee09d8 JG |
173 | { |
174 | if (pmd_protnone(pmd)) | |
175 | return 0; | |
f88a1e90 JG |
176 | return pmd_write(pmd) ? range->flags[HMM_PFN_VALID] | |
177 | range->flags[HMM_PFN_WRITE] : | |
178 | range->flags[HMM_PFN_VALID]; | |
da4c3c73 JG |
179 | } |
180 | ||
992de9a8 | 181 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
9d3973d6 CH |
182 | static int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr, |
183 | unsigned long end, uint64_t *pfns, pmd_t pmd) | |
184 | { | |
53f5c3f4 | 185 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
f88a1e90 | 186 | struct hmm_range *range = hmm_vma_walk->range; |
2aee09d8 | 187 | unsigned long pfn, npages, i; |
a3eb13c1 | 188 | unsigned int required_fault; |
f88a1e90 | 189 | uint64_t cpu_flags; |
53f5c3f4 | 190 | |
2aee09d8 | 191 | npages = (end - addr) >> PAGE_SHIFT; |
f88a1e90 | 192 | cpu_flags = pmd_to_hmm_pfn_flags(range, pmd); |
a3eb13c1 JG |
193 | required_fault = |
194 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, cpu_flags); | |
195 | if (required_fault) | |
196 | return hmm_vma_fault(addr, end, required_fault, walk); | |
53f5c3f4 | 197 | |
309f9a4f | 198 | pfn = pmd_pfn(pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT); |
068354ad | 199 | for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++) |
391aab11 | 200 | pfns[i] = hmm_device_entry_from_pfn(range, pfn) | cpu_flags; |
53f5c3f4 JG |
201 | hmm_vma_walk->last = end; |
202 | return 0; | |
203 | } | |
9d3973d6 CH |
204 | #else /* CONFIG_TRANSPARENT_HUGEPAGE */ |
205 | /* stub to allow the code below to compile */ | |
206 | int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr, | |
207 | unsigned long end, uint64_t *pfns, pmd_t pmd); | |
208 | #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ | |
53f5c3f4 | 209 | |
08ddddda CH |
210 | static inline bool hmm_is_device_private_entry(struct hmm_range *range, |
211 | swp_entry_t entry) | |
212 | { | |
213 | return is_device_private_entry(entry) && | |
214 | device_private_entry_to_page(entry)->pgmap->owner == | |
215 | range->dev_private_owner; | |
216 | } | |
217 | ||
f88a1e90 | 218 | static inline uint64_t pte_to_hmm_pfn_flags(struct hmm_range *range, pte_t pte) |
2aee09d8 | 219 | { |
789c2af8 | 220 | if (pte_none(pte) || !pte_present(pte) || pte_protnone(pte)) |
2aee09d8 | 221 | return 0; |
f88a1e90 JG |
222 | return pte_write(pte) ? range->flags[HMM_PFN_VALID] | |
223 | range->flags[HMM_PFN_WRITE] : | |
224 | range->flags[HMM_PFN_VALID]; | |
2aee09d8 JG |
225 | } |
226 | ||
53f5c3f4 JG |
227 | static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr, |
228 | unsigned long end, pmd_t *pmdp, pte_t *ptep, | |
229 | uint64_t *pfn) | |
230 | { | |
231 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
f88a1e90 | 232 | struct hmm_range *range = hmm_vma_walk->range; |
a3eb13c1 | 233 | unsigned int required_fault; |
2aee09d8 | 234 | uint64_t cpu_flags; |
53f5c3f4 | 235 | pte_t pte = *ptep; |
f88a1e90 | 236 | uint64_t orig_pfn = *pfn; |
53f5c3f4 | 237 | |
f88a1e90 | 238 | *pfn = range->values[HMM_PFN_NONE]; |
53f5c3f4 | 239 | if (pte_none(pte)) { |
a3eb13c1 JG |
240 | required_fault = hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0); |
241 | if (required_fault) | |
53f5c3f4 JG |
242 | goto fault; |
243 | return 0; | |
244 | } | |
245 | ||
246 | if (!pte_present(pte)) { | |
247 | swp_entry_t entry = pte_to_swp_entry(pte); | |
248 | ||
53f5c3f4 | 249 | /* |
17ffdc48 CH |
250 | * Never fault in device private pages pages, but just report |
251 | * the PFN even if not present. | |
53f5c3f4 | 252 | */ |
08ddddda | 253 | if (hmm_is_device_private_entry(range, entry)) { |
391aab11 JG |
254 | *pfn = hmm_device_entry_from_pfn(range, |
255 | swp_offset(entry)); | |
17ffdc48 CH |
256 | *pfn |= range->flags[HMM_PFN_VALID]; |
257 | if (is_write_device_private_entry(entry)) | |
258 | *pfn |= range->flags[HMM_PFN_WRITE]; | |
53f5c3f4 JG |
259 | return 0; |
260 | } | |
261 | ||
a3eb13c1 JG |
262 | required_fault = hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0); |
263 | if (!required_fault) | |
53f5c3f4 | 264 | return 0; |
76612d6c JG |
265 | |
266 | if (!non_swap_entry(entry)) | |
267 | goto fault; | |
268 | ||
269 | if (is_migration_entry(entry)) { | |
270 | pte_unmap(ptep); | |
271 | hmm_vma_walk->last = addr; | |
272 | migration_entry_wait(walk->mm, pmdp, addr); | |
273 | return -EBUSY; | |
53f5c3f4 JG |
274 | } |
275 | ||
276 | /* Report error for everything else */ | |
dfdc2207 | 277 | pte_unmap(ptep); |
f88a1e90 | 278 | *pfn = range->values[HMM_PFN_ERROR]; |
53f5c3f4 JG |
279 | return -EFAULT; |
280 | } | |
281 | ||
76612d6c | 282 | cpu_flags = pte_to_hmm_pfn_flags(range, pte); |
a3eb13c1 JG |
283 | required_fault = hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags); |
284 | if (required_fault) | |
53f5c3f4 JG |
285 | goto fault; |
286 | ||
40550627 JG |
287 | /* |
288 | * Since each architecture defines a struct page for the zero page, just | |
289 | * fall through and treat it like a normal page. | |
290 | */ | |
291 | if (pte_special(pte) && !is_zero_pfn(pte_pfn(pte))) { | |
a3eb13c1 | 292 | if (hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0)) { |
dfdc2207 | 293 | pte_unmap(ptep); |
ac541f25 RC |
294 | return -EFAULT; |
295 | } | |
40550627 JG |
296 | *pfn = range->values[HMM_PFN_SPECIAL]; |
297 | return 0; | |
992de9a8 JG |
298 | } |
299 | ||
391aab11 | 300 | *pfn = hmm_device_entry_from_pfn(range, pte_pfn(pte)) | cpu_flags; |
53f5c3f4 JG |
301 | return 0; |
302 | ||
303 | fault: | |
304 | pte_unmap(ptep); | |
305 | /* Fault any virtual address we were asked to fault */ | |
a3eb13c1 | 306 | return hmm_vma_fault(addr, end, required_fault, walk); |
53f5c3f4 JG |
307 | } |
308 | ||
da4c3c73 JG |
309 | static int hmm_vma_walk_pmd(pmd_t *pmdp, |
310 | unsigned long start, | |
311 | unsigned long end, | |
312 | struct mm_walk *walk) | |
313 | { | |
74eee180 JG |
314 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
315 | struct hmm_range *range = hmm_vma_walk->range; | |
2288a9a6 JG |
316 | uint64_t *pfns = &range->pfns[(start - range->start) >> PAGE_SHIFT]; |
317 | unsigned long npages = (end - start) >> PAGE_SHIFT; | |
318 | unsigned long addr = start; | |
da4c3c73 | 319 | pte_t *ptep; |
d08faca0 | 320 | pmd_t pmd; |
da4c3c73 | 321 | |
da4c3c73 | 322 | again: |
d08faca0 JG |
323 | pmd = READ_ONCE(*pmdp); |
324 | if (pmd_none(pmd)) | |
b7a16c7a | 325 | return hmm_vma_walk_hole(start, end, -1, walk); |
da4c3c73 | 326 | |
d08faca0 | 327 | if (thp_migration_supported() && is_pmd_migration_entry(pmd)) { |
a3eb13c1 | 328 | if (hmm_range_need_fault(hmm_vma_walk, pfns, npages, 0)) { |
d08faca0 | 329 | hmm_vma_walk->last = addr; |
d2e8d551 | 330 | pmd_migration_entry_wait(walk->mm, pmdp); |
73231612 | 331 | return -EBUSY; |
d08faca0 | 332 | } |
7d082987 | 333 | return hmm_pfns_fill(start, end, range, HMM_PFN_NONE); |
2288a9a6 JG |
334 | } |
335 | ||
336 | if (!pmd_present(pmd)) { | |
a3eb13c1 | 337 | if (hmm_range_need_fault(hmm_vma_walk, pfns, npages, 0)) |
2288a9a6 | 338 | return -EFAULT; |
d28c2c9a | 339 | return hmm_pfns_fill(start, end, range, HMM_PFN_ERROR); |
2288a9a6 | 340 | } |
da4c3c73 | 341 | |
d08faca0 | 342 | if (pmd_devmap(pmd) || pmd_trans_huge(pmd)) { |
da4c3c73 | 343 | /* |
d2e8d551 | 344 | * No need to take pmd_lock here, even if some other thread |
da4c3c73 JG |
345 | * is splitting the huge pmd we will get that event through |
346 | * mmu_notifier callback. | |
347 | * | |
d2e8d551 | 348 | * So just read pmd value and check again it's a transparent |
da4c3c73 JG |
349 | * huge or device mapping one and compute corresponding pfn |
350 | * values. | |
351 | */ | |
352 | pmd = pmd_read_atomic(pmdp); | |
353 | barrier(); | |
354 | if (!pmd_devmap(pmd) && !pmd_trans_huge(pmd)) | |
355 | goto again; | |
74eee180 | 356 | |
2288a9a6 | 357 | return hmm_vma_handle_pmd(walk, addr, end, pfns, pmd); |
da4c3c73 JG |
358 | } |
359 | ||
d08faca0 | 360 | /* |
d2e8d551 | 361 | * We have handled all the valid cases above ie either none, migration, |
d08faca0 JG |
362 | * huge or transparent huge. At this point either it is a valid pmd |
363 | * entry pointing to pte directory or it is a bad pmd that will not | |
364 | * recover. | |
365 | */ | |
2288a9a6 | 366 | if (pmd_bad(pmd)) { |
a3eb13c1 | 367 | if (hmm_range_need_fault(hmm_vma_walk, pfns, npages, 0)) |
2288a9a6 | 368 | return -EFAULT; |
d28c2c9a | 369 | return hmm_pfns_fill(start, end, range, HMM_PFN_ERROR); |
2288a9a6 | 370 | } |
da4c3c73 JG |
371 | |
372 | ptep = pte_offset_map(pmdp, addr); | |
2288a9a6 | 373 | for (; addr < end; addr += PAGE_SIZE, ptep++, pfns++) { |
53f5c3f4 | 374 | int r; |
74eee180 | 375 | |
2288a9a6 | 376 | r = hmm_vma_handle_pte(walk, addr, end, pmdp, ptep, pfns); |
53f5c3f4 | 377 | if (r) { |
dfdc2207 | 378 | /* hmm_vma_handle_pte() did pte_unmap() */ |
53f5c3f4 JG |
379 | hmm_vma_walk->last = addr; |
380 | return r; | |
74eee180 | 381 | } |
da4c3c73 JG |
382 | } |
383 | pte_unmap(ptep - 1); | |
384 | ||
53f5c3f4 | 385 | hmm_vma_walk->last = addr; |
da4c3c73 JG |
386 | return 0; |
387 | } | |
388 | ||
f0b3c45c CH |
389 | #if defined(CONFIG_ARCH_HAS_PTE_DEVMAP) && \ |
390 | defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) | |
391 | static inline uint64_t pud_to_hmm_pfn_flags(struct hmm_range *range, pud_t pud) | |
392 | { | |
393 | if (!pud_present(pud)) | |
394 | return 0; | |
395 | return pud_write(pud) ? range->flags[HMM_PFN_VALID] | | |
396 | range->flags[HMM_PFN_WRITE] : | |
397 | range->flags[HMM_PFN_VALID]; | |
398 | } | |
399 | ||
400 | static int hmm_vma_walk_pud(pud_t *pudp, unsigned long start, unsigned long end, | |
401 | struct mm_walk *walk) | |
992de9a8 JG |
402 | { |
403 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
404 | struct hmm_range *range = hmm_vma_walk->range; | |
3afc4236 | 405 | unsigned long addr = start; |
992de9a8 | 406 | pud_t pud; |
3afc4236 SP |
407 | int ret = 0; |
408 | spinlock_t *ptl = pud_trans_huge_lock(pudp, walk->vma); | |
409 | ||
410 | if (!ptl) | |
411 | return 0; | |
412 | ||
413 | /* Normally we don't want to split the huge page */ | |
414 | walk->action = ACTION_CONTINUE; | |
992de9a8 | 415 | |
992de9a8 | 416 | pud = READ_ONCE(*pudp); |
3afc4236 | 417 | if (pud_none(pud)) { |
05fc1df9 JG |
418 | spin_unlock(ptl); |
419 | return hmm_vma_walk_hole(start, end, -1, walk); | |
3afc4236 | 420 | } |
992de9a8 JG |
421 | |
422 | if (pud_huge(pud) && pud_devmap(pud)) { | |
423 | unsigned long i, npages, pfn; | |
a3eb13c1 | 424 | unsigned int required_fault; |
992de9a8 | 425 | uint64_t *pfns, cpu_flags; |
992de9a8 | 426 | |
3afc4236 | 427 | if (!pud_present(pud)) { |
05fc1df9 JG |
428 | spin_unlock(ptl); |
429 | return hmm_vma_walk_hole(start, end, -1, walk); | |
3afc4236 | 430 | } |
992de9a8 JG |
431 | |
432 | i = (addr - range->start) >> PAGE_SHIFT; | |
433 | npages = (end - addr) >> PAGE_SHIFT; | |
434 | pfns = &range->pfns[i]; | |
435 | ||
436 | cpu_flags = pud_to_hmm_pfn_flags(range, pud); | |
a3eb13c1 JG |
437 | required_fault = hmm_range_need_fault(hmm_vma_walk, pfns, |
438 | npages, cpu_flags); | |
439 | if (required_fault) { | |
05fc1df9 | 440 | spin_unlock(ptl); |
a3eb13c1 | 441 | return hmm_vma_fault(addr, end, required_fault, walk); |
3afc4236 | 442 | } |
992de9a8 | 443 | |
992de9a8 | 444 | pfn = pud_pfn(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT); |
068354ad | 445 | for (i = 0; i < npages; ++i, ++pfn) |
391aab11 JG |
446 | pfns[i] = hmm_device_entry_from_pfn(range, pfn) | |
447 | cpu_flags; | |
992de9a8 | 448 | hmm_vma_walk->last = end; |
3afc4236 | 449 | goto out_unlock; |
992de9a8 JG |
450 | } |
451 | ||
3afc4236 SP |
452 | /* Ask for the PUD to be split */ |
453 | walk->action = ACTION_SUBTREE; | |
992de9a8 | 454 | |
3afc4236 SP |
455 | out_unlock: |
456 | spin_unlock(ptl); | |
457 | return ret; | |
992de9a8 | 458 | } |
f0b3c45c CH |
459 | #else |
460 | #define hmm_vma_walk_pud NULL | |
461 | #endif | |
992de9a8 | 462 | |
251bbe59 | 463 | #ifdef CONFIG_HUGETLB_PAGE |
63d5066f JG |
464 | static int hmm_vma_walk_hugetlb_entry(pte_t *pte, unsigned long hmask, |
465 | unsigned long start, unsigned long end, | |
466 | struct mm_walk *walk) | |
467 | { | |
05c23af4 | 468 | unsigned long addr = start, i, pfn; |
63d5066f JG |
469 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
470 | struct hmm_range *range = hmm_vma_walk->range; | |
471 | struct vm_area_struct *vma = walk->vma; | |
63d5066f | 472 | uint64_t orig_pfn, cpu_flags; |
a3eb13c1 | 473 | unsigned int required_fault; |
63d5066f JG |
474 | spinlock_t *ptl; |
475 | pte_t entry; | |
63d5066f | 476 | |
d2e8d551 | 477 | ptl = huge_pte_lock(hstate_vma(vma), walk->mm, pte); |
63d5066f JG |
478 | entry = huge_ptep_get(pte); |
479 | ||
7f08263d | 480 | i = (start - range->start) >> PAGE_SHIFT; |
63d5066f JG |
481 | orig_pfn = range->pfns[i]; |
482 | range->pfns[i] = range->values[HMM_PFN_NONE]; | |
483 | cpu_flags = pte_to_hmm_pfn_flags(range, entry); | |
a3eb13c1 JG |
484 | required_fault = hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags); |
485 | if (required_fault) { | |
45050692 | 486 | spin_unlock(ptl); |
a3eb13c1 | 487 | return hmm_vma_fault(addr, end, required_fault, walk); |
63d5066f JG |
488 | } |
489 | ||
05c23af4 | 490 | pfn = pte_pfn(entry) + ((start & ~hmask) >> PAGE_SHIFT); |
7f08263d | 491 | for (; addr < end; addr += PAGE_SIZE, i++, pfn++) |
391aab11 JG |
492 | range->pfns[i] = hmm_device_entry_from_pfn(range, pfn) | |
493 | cpu_flags; | |
63d5066f | 494 | hmm_vma_walk->last = end; |
63d5066f | 495 | spin_unlock(ptl); |
45050692 | 496 | return 0; |
63d5066f | 497 | } |
251bbe59 CH |
498 | #else |
499 | #define hmm_vma_walk_hugetlb_entry NULL | |
500 | #endif /* CONFIG_HUGETLB_PAGE */ | |
63d5066f | 501 | |
d28c2c9a RC |
502 | static int hmm_vma_walk_test(unsigned long start, unsigned long end, |
503 | struct mm_walk *walk) | |
33cd47dc | 504 | { |
d28c2c9a RC |
505 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
506 | struct hmm_range *range = hmm_vma_walk->range; | |
507 | struct vm_area_struct *vma = walk->vma; | |
508 | ||
a3eb13c1 JG |
509 | if (!(vma->vm_flags & (VM_IO | VM_PFNMAP | VM_MIXEDMAP)) && |
510 | vma->vm_flags & VM_READ) | |
511 | return 0; | |
512 | ||
d28c2c9a | 513 | /* |
a3eb13c1 JG |
514 | * vma ranges that don't have struct page backing them or map I/O |
515 | * devices directly cannot be handled by hmm_range_fault(). | |
c2579c9c | 516 | * |
d28c2c9a | 517 | * If the vma does not allow read access, then assume that it does not |
c2579c9c JG |
518 | * allow write access either. HMM does not support architectures that |
519 | * allow write without read. | |
a3eb13c1 JG |
520 | * |
521 | * If a fault is requested for an unsupported range then it is a hard | |
522 | * failure. | |
d28c2c9a | 523 | */ |
a3eb13c1 JG |
524 | if (hmm_range_need_fault(hmm_vma_walk, |
525 | range->pfns + | |
526 | ((start - range->start) >> PAGE_SHIFT), | |
527 | (end - start) >> PAGE_SHIFT, 0)) | |
528 | return -EFAULT; | |
d28c2c9a | 529 | |
a3eb13c1 JG |
530 | hmm_pfns_fill(start, end, range, HMM_PFN_ERROR); |
531 | hmm_vma_walk->last = end; | |
d28c2c9a | 532 | |
a3eb13c1 JG |
533 | /* Skip this vma and continue processing the next vma. */ |
534 | return 1; | |
33cd47dc JG |
535 | } |
536 | ||
7b86ac33 CH |
537 | static const struct mm_walk_ops hmm_walk_ops = { |
538 | .pud_entry = hmm_vma_walk_pud, | |
539 | .pmd_entry = hmm_vma_walk_pmd, | |
540 | .pte_hole = hmm_vma_walk_hole, | |
541 | .hugetlb_entry = hmm_vma_walk_hugetlb_entry, | |
d28c2c9a | 542 | .test_walk = hmm_vma_walk_test, |
7b86ac33 CH |
543 | }; |
544 | ||
9a4903e4 CH |
545 | /** |
546 | * hmm_range_fault - try to fault some address in a virtual address range | |
547 | * @range: range being faulted | |
548 | * @flags: HMM_FAULT_* flags | |
549 | * | |
550 | * Return: the number of valid pages in range->pfns[] (from range start | |
551 | * address), which may be zero. On error one of the following status codes | |
552 | * can be returned: | |
73231612 | 553 | * |
9a4903e4 CH |
554 | * -EINVAL: Invalid arguments or mm or virtual address is in an invalid vma |
555 | * (e.g., device file vma). | |
556 | * -ENOMEM: Out of memory. | |
557 | * -EPERM: Invalid permission (e.g., asking for write and range is read | |
558 | * only). | |
9a4903e4 CH |
559 | * -EBUSY: The range has been invalidated and the caller needs to wait for |
560 | * the invalidation to finish. | |
561 | * -EFAULT: Invalid (i.e., either no valid vma or it is illegal to access | |
562 | * that range) number of valid pages in range->pfns[] (from | |
563 | * range start address). | |
74eee180 JG |
564 | * |
565 | * This is similar to a regular CPU page fault except that it will not trigger | |
73231612 JG |
566 | * any memory migration if the memory being faulted is not accessible by CPUs |
567 | * and caller does not ask for migration. | |
74eee180 | 568 | * |
ff05c0c6 JG |
569 | * On error, for one virtual address in the range, the function will mark the |
570 | * corresponding HMM pfn entry with an error flag. | |
74eee180 | 571 | */ |
9a4903e4 | 572 | long hmm_range_fault(struct hmm_range *range, unsigned int flags) |
74eee180 | 573 | { |
d28c2c9a RC |
574 | struct hmm_vma_walk hmm_vma_walk = { |
575 | .range = range, | |
576 | .last = range->start, | |
577 | .flags = flags, | |
578 | }; | |
a22dd506 | 579 | struct mm_struct *mm = range->notifier->mm; |
74eee180 JG |
580 | int ret; |
581 | ||
04ec32fb | 582 | lockdep_assert_held(&mm->mmap_sem); |
704f3f2c | 583 | |
a3e0d41c JG |
584 | do { |
585 | /* If range is no longer valid force retry. */ | |
a22dd506 JG |
586 | if (mmu_interval_check_retry(range->notifier, |
587 | range->notifier_seq)) | |
2bcbeaef | 588 | return -EBUSY; |
d28c2c9a RC |
589 | ret = walk_page_range(mm, hmm_vma_walk.last, range->end, |
590 | &hmm_walk_ops, &hmm_vma_walk); | |
591 | } while (ret == -EBUSY); | |
74eee180 | 592 | |
d28c2c9a RC |
593 | if (ret) |
594 | return ret; | |
73231612 | 595 | return (hmm_vma_walk.last - range->start) >> PAGE_SHIFT; |
74eee180 | 596 | } |
73231612 | 597 | EXPORT_SYMBOL(hmm_range_fault); |