1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Stand-alone page-table allocator for hyp stage-1 and guest stage-2.
4 * No bombay mix was harmed in the writing of this file.
5 *
6 * Copyright (C) 2020 Google LLC
7 * Author: Will Deacon <will@kernel.org>
8 */
9
10 #include <linux/bitfield.h>
11 #include <asm/kvm_pgtable.h>
12 #include <asm/stage2_pgtable.h>
13
14
15 #define KVM_PTE_TYPE BIT(1)
16 #define KVM_PTE_TYPE_BLOCK 0
17 #define KVM_PTE_TYPE_PAGE 1
18 #define KVM_PTE_TYPE_TABLE 1
19
20 #define KVM_PTE_LEAF_ATTR_LO GENMASK(11, 2)
21
22 #define KVM_PTE_LEAF_ATTR_LO_S1_ATTRIDX GENMASK(4, 2)
23 #define KVM_PTE_LEAF_ATTR_LO_S1_AP GENMASK(7, 6)
24 #define KVM_PTE_LEAF_ATTR_LO_S1_AP_RO \
25 ({ cpus_have_final_cap(ARM64_KVM_HVHE) ? 2 : 3; })
26 #define KVM_PTE_LEAF_ATTR_LO_S1_AP_RW \
27 ({ cpus_have_final_cap(ARM64_KVM_HVHE) ? 0 : 1; })
28 #define KVM_PTE_LEAF_ATTR_LO_S1_SH GENMASK(9, 8)
29 #define KVM_PTE_LEAF_ATTR_LO_S1_SH_IS 3
30 #define KVM_PTE_LEAF_ATTR_LO_S1_AF BIT(10)
31
32 #define KVM_PTE_LEAF_ATTR_LO_S2_MEMATTR GENMASK(5, 2)
33 #define KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R BIT(6)
34 #define KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W BIT(7)
35 #define KVM_PTE_LEAF_ATTR_LO_S2_SH GENMASK(9, 8)
36 #define KVM_PTE_LEAF_ATTR_LO_S2_SH_IS 3
37 #define KVM_PTE_LEAF_ATTR_LO_S2_AF BIT(10)
38
39 #define KVM_PTE_LEAF_ATTR_HI GENMASK(63, 50)
40
41 #define KVM_PTE_LEAF_ATTR_HI_SW GENMASK(58, 55)
42
43 #define KVM_PTE_LEAF_ATTR_HI_S1_XN BIT(54)
44
45 #define KVM_PTE_LEAF_ATTR_HI_S2_XN BIT(54)
46
47 #define KVM_PTE_LEAF_ATTR_HI_S1_GP BIT(50)
48
49 #define KVM_PTE_LEAF_ATTR_S2_PERMS (KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | \
50 KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | \
51 KVM_PTE_LEAF_ATTR_HI_S2_XN)
52
53 #define KVM_INVALID_PTE_OWNER_MASK GENMASK(9, 2)
54 #define KVM_MAX_OWNER_ID 1
55
56 /*
57 * Used to indicate a pte for which a 'break-before-make' sequence is in
58 * progress.
59 */
60 #define KVM_INVALID_PTE_LOCKED BIT(10)
61
62 struct kvm_pgtable_walk_data {
63 struct kvm_pgtable_walker *walker;
64
65 const u64 start;
66 u64 addr;
67 const u64 end;
68 };
69
70 static bool kvm_pgtable_walk_skip_bbm_tlbi(const struct kvm_pgtable_visit_ctx *ctx)
71 {
72 return unlikely(ctx->flags & KVM_PGTABLE_WALK_SKIP_BBM_TLBI);
73 }
74
75 static bool kvm_pgtable_walk_skip_cmo(const struct kvm_pgtable_visit_ctx *ctx)
76 {
77 return unlikely(ctx->flags & KVM_PGTABLE_WALK_SKIP_CMO);
78 }
79
80 static bool kvm_phys_is_valid(u64 phys)
81 {
82 u64 parange_max = kvm_get_parange_max();
83 u8 shift = id_aa64mmfr0_parange_to_phys_shift(parange_max);
84
85 return phys < BIT(shift);
86 }
87
88 static bool kvm_block_mapping_supported(const struct kvm_pgtable_visit_ctx *ctx, u64 phys)
89 {
90 u64 granule = kvm_granule_size(ctx->level);
91
92 if (!kvm_level_supports_block_mapping(ctx->level))
93 return false;
94
95 if (granule > (ctx->end - ctx->addr))
96 return false;
97
98 if (kvm_phys_is_valid(phys) && !IS_ALIGNED(phys, granule))
99 return false;
100
101 return IS_ALIGNED(ctx->addr, granule);
102 }
103
104 static u32 kvm_pgtable_idx(struct kvm_pgtable_walk_data *data, s8 level)
105 {
106 u64 shift = kvm_granule_shift(level);
107 u64 mask = BIT(PAGE_SHIFT - 3) - 1;
108
109 return (data->addr >> shift) & mask;
110 }
111
112 static u32 kvm_pgd_page_idx(struct kvm_pgtable *pgt, u64 addr)
113 {
114 u64 shift = kvm_granule_shift(pgt->start_level - 1); /* May underflow */
115 u64 mask = BIT(pgt->ia_bits) - 1;
116
117 return (addr & mask) >> shift;
118 }
119
120 static u32 kvm_pgd_pages(u32 ia_bits, s8 start_level)
121 {
122 struct kvm_pgtable pgt = {
123 .ia_bits = ia_bits,
124 .start_level = start_level,
125 };
126
127 return kvm_pgd_page_idx(&pgt, -1ULL) + 1;
128 }
129
130 static bool kvm_pte_table(kvm_pte_t pte, s8 level)
131 {
132 if (level == KVM_PGTABLE_LAST_LEVEL)
133 return false;
134
135 if (!kvm_pte_valid(pte))
136 return false;
137
138 return FIELD_GET(KVM_PTE_TYPE, pte) == KVM_PTE_TYPE_TABLE;
139 }
140
141 static kvm_pte_t *kvm_pte_follow(kvm_pte_t pte, struct kvm_pgtable_mm_ops *mm_ops)
142 {
143 return mm_ops->phys_to_virt(kvm_pte_to_phys(pte));
144 }
145
146 static void kvm_clear_pte(kvm_pte_t *ptep)
147 {
148 WRITE_ONCE(*ptep, 0);
149 }
150
151 static kvm_pte_t kvm_init_table_pte(kvm_pte_t *childp, struct kvm_pgtable_mm_ops *mm_ops)
152 {
153 kvm_pte_t pte = kvm_phys_to_pte(mm_ops->virt_to_phys(childp));
154
155 pte |= FIELD_PREP(KVM_PTE_TYPE, KVM_PTE_TYPE_TABLE);
156 pte |= KVM_PTE_VALID;
157 return pte;
158 }
159
160 static kvm_pte_t kvm_init_valid_leaf_pte(u64 pa, kvm_pte_t attr, s8 level)
161 {
162 kvm_pte_t pte = kvm_phys_to_pte(pa);
163 u64 type = (level == KVM_PGTABLE_LAST_LEVEL) ? KVM_PTE_TYPE_PAGE :
164 KVM_PTE_TYPE_BLOCK;
165
166 pte |= attr & (KVM_PTE_LEAF_ATTR_LO | KVM_PTE_LEAF_ATTR_HI);
167 pte |= FIELD_PREP(KVM_PTE_TYPE, type);
168 pte |= KVM_PTE_VALID;
169
170 return pte;
171 }
172
173 static kvm_pte_t kvm_init_invalid_leaf_owner(u8 owner_id)
174 {
175 return FIELD_PREP(KVM_INVALID_PTE_OWNER_MASK, owner_id);
176 }
177
178 static int kvm_pgtable_visitor_cb(struct kvm_pgtable_walk_data *data,
179 const struct kvm_pgtable_visit_ctx *ctx,
180 enum kvm_pgtable_walk_flags visit)
181 {
182 struct kvm_pgtable_walker *walker = data->walker;
183
184 /* Ensure the appropriate lock is held (e.g. RCU lock for stage-2 MMU) */
185 WARN_ON_ONCE(kvm_pgtable_walk_shared(ctx) && !kvm_pgtable_walk_lock_held());
186 return walker->cb(ctx, visit);
187 }
188
189 static bool kvm_pgtable_walk_continue(const struct kvm_pgtable_walker *walker,
190 int r)
191 {
192 /*
193 * Visitor callbacks return EAGAIN when the conditions that led to a
194 * fault are no longer reflected in the page tables due to a race to
195 * update a PTE. In the context of a fault handler this is interpreted
196 * as a signal to retry guest execution.
197 *
198 * Ignore the return code altogether for walkers outside a fault handler
199 * (e.g. write protecting a range of memory) and chug along with the
200 * page table walk.
201 */
202 if (r == -EAGAIN)
203 return !(walker->flags & KVM_PGTABLE_WALK_HANDLE_FAULT);
204
205 return !r;
206 }
207
208 static int __kvm_pgtable_walk(struct kvm_pgtable_walk_data *data,
209 struct kvm_pgtable_mm_ops *mm_ops, kvm_pteref_t pgtable, s8 level);
210
211 static inline int __kvm_pgtable_visit(struct kvm_pgtable_walk_data *data,
212 struct kvm_pgtable_mm_ops *mm_ops,
213 kvm_pteref_t pteref, s8 level)
214 {
215 enum kvm_pgtable_walk_flags flags = data->walker->flags;
216 kvm_pte_t *ptep = kvm_dereference_pteref(data->walker, pteref);
217 struct kvm_pgtable_visit_ctx ctx = {
218 .ptep = ptep,
219 .old = READ_ONCE(*ptep),
220 .arg = data->walker->arg,
221 .mm_ops = mm_ops,
222 .start = data->start,
223 .addr = data->addr,
224 .end = data->end,
225 .level = level,
226 .flags = flags,
227 };
228 int ret = 0;
229 bool reload = false;
230 kvm_pteref_t childp;
231 bool table = kvm_pte_table(ctx.old, level);
232
233 if (table && (ctx.flags & KVM_PGTABLE_WALK_TABLE_PRE)) {
234 ret = kvm_pgtable_visitor_cb(data, &ctx, KVM_PGTABLE_WALK_TABLE_PRE);
235 reload = true;
236 }
237
238 if (!table && (ctx.flags & KVM_PGTABLE_WALK_LEAF)) {
239 ret = kvm_pgtable_visitor_cb(data, &ctx, KVM_PGTABLE_WALK_LEAF);
240 reload = true;
241 }
242
243 /*
244 * Reload the page table after invoking the walker callback for leaf
245 * entries or after pre-order traversal, to allow the walker to descend
246 * into a newly installed or replaced table.
247 */
248 if (reload) {
249 ctx.old = READ_ONCE(*ptep);
250 table = kvm_pte_table(ctx.old, level);
251 }
252
253 if (!kvm_pgtable_walk_continue(data->walker, ret))
254 goto out;
255
256 if (!table) {
257 data->addr = ALIGN_DOWN(data->addr, kvm_granule_size(level));
258 data->addr += kvm_granule_size(level);
259 goto out;
260 }
261
262 childp = (kvm_pteref_t)kvm_pte_follow(ctx.old, mm_ops);
263 ret = __kvm_pgtable_walk(data, mm_ops, childp, level + 1);
264 if (!kvm_pgtable_walk_continue(data->walker, ret))
265 goto out;
266
267 if (ctx.flags & KVM_PGTABLE_WALK_TABLE_POST)
268 ret = kvm_pgtable_visitor_cb(data, &ctx, KVM_PGTABLE_WALK_TABLE_POST);
269
270 out:
271 if (kvm_pgtable_walk_continue(data->walker, ret))
272 return 0;
273
274 return ret;
275 }
276
277 static int __kvm_pgtable_walk(struct kvm_pgtable_walk_data *data,
278 struct kvm_pgtable_mm_ops *mm_ops, kvm_pteref_t pgtable, s8 level)
279 {
280 u32 idx;
281 int ret = 0;
282
283 if (WARN_ON_ONCE(level < KVM_PGTABLE_FIRST_LEVEL ||
284 level > KVM_PGTABLE_LAST_LEVEL))
285 return -EINVAL;
286
287 for (idx = kvm_pgtable_idx(data, level); idx < PTRS_PER_PTE; ++idx) {
288 kvm_pteref_t pteref = &pgtable[idx];
289
290 if (data->addr >= data->end)
291 break;
292
293 ret = __kvm_pgtable_visit(data, mm_ops, pteref, level);
294 if (ret)
295 break;
296 }
297
298 return ret;
299 }
300
301 static int _kvm_pgtable_walk(struct kvm_pgtable *pgt, struct kvm_pgtable_walk_data *data)
302 {
303 u32 idx;
304 int ret = 0;
305 u64 limit = BIT(pgt->ia_bits);
306
307 if (data->addr > limit || data->end > limit)
308 return -ERANGE;
309
310 if (!pgt->pgd)
311 return -EINVAL;
312
313 for (idx = kvm_pgd_page_idx(pgt, data->addr); data->addr < data->end; ++idx) {
314 kvm_pteref_t pteref = &pgt->pgd[idx * PTRS_PER_PTE];
315
316 ret = __kvm_pgtable_walk(data, pgt->mm_ops, pteref, pgt->start_level);
317 if (ret)
318 break;
319 }
320
321 return ret;
322 }
323
324 int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size,
325 struct kvm_pgtable_walker *walker)
326 {
327 struct kvm_pgtable_walk_data walk_data = {
328 .start = ALIGN_DOWN(addr, PAGE_SIZE),
329 .addr = ALIGN_DOWN(addr, PAGE_SIZE),
330 .end = PAGE_ALIGN(walk_data.addr + size),
331 .walker = walker,
332 };
333 int r;
334
335 r = kvm_pgtable_walk_begin(walker);
336 if (r)
337 return r;
338
339 r = _kvm_pgtable_walk(pgt, &walk_data);
340 kvm_pgtable_walk_end(walker);
341
342 return r;
343 }
344
345 struct leaf_walk_data {
346 kvm_pte_t pte;
347 s8 level;
348 };
349
350 static int leaf_walker(const struct kvm_pgtable_visit_ctx *ctx,
351 enum kvm_pgtable_walk_flags visit)
352 {
353 struct leaf_walk_data *data = ctx->arg;
354
355 data->pte = ctx->old;
356 data->level = ctx->level;
357
358 return 0;
359 }
360
361 int kvm_pgtable_get_leaf(struct kvm_pgtable *pgt, u64 addr,
362 kvm_pte_t *ptep, s8 *level)
363 {
364 struct leaf_walk_data data;
365 struct kvm_pgtable_walker walker = {
366 .cb = leaf_walker,
367 .flags = KVM_PGTABLE_WALK_LEAF,
368 .arg = &data,
369 };
370 int ret;
371
372 ret = kvm_pgtable_walk(pgt, ALIGN_DOWN(addr, PAGE_SIZE),
373 PAGE_SIZE, &walker);
374 if (!ret) {
375 if (ptep)
376 *ptep = data.pte;
377 if (level)
378 *level = data.level;
379 }
380
381 return ret;
382 }
383
384 struct hyp_map_data {
385 const u64 phys;
386 kvm_pte_t attr;
387 };
388
389 static int hyp_set_prot_attr(enum kvm_pgtable_prot prot, kvm_pte_t *ptep)
390 {
391 bool device = prot & KVM_PGTABLE_PROT_DEVICE;
392 u32 mtype = device ? MT_DEVICE_nGnRE : MT_NORMAL;
393 kvm_pte_t attr = FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_ATTRIDX, mtype);
394 u32 sh = KVM_PTE_LEAF_ATTR_LO_S1_SH_IS;
395 u32 ap = (prot & KVM_PGTABLE_PROT_W) ? KVM_PTE_LEAF_ATTR_LO_S1_AP_RW :
396 KVM_PTE_LEAF_ATTR_LO_S1_AP_RO;
397
398 if (!(prot & KVM_PGTABLE_PROT_R))
399 return -EINVAL;
400
401 if (prot & KVM_PGTABLE_PROT_X) {
402 if (prot & KVM_PGTABLE_PROT_W)
403 return -EINVAL;
404
405 if (device)
406 return -EINVAL;
407
408 if (system_supports_bti_kernel())
409 attr |= KVM_PTE_LEAF_ATTR_HI_S1_GP;
410 } else {
411 attr |= KVM_PTE_LEAF_ATTR_HI_S1_XN;
412 }
413
414 attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_AP, ap);
415 if (!kvm_lpa2_is_enabled())
416 attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_SH, sh);
417 attr |= KVM_PTE_LEAF_ATTR_LO_S1_AF;
418 attr |= prot & KVM_PTE_LEAF_ATTR_HI_SW;
419 *ptep = attr;
420
421 return 0;
422 }
423
424 enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte)
425 {
426 enum kvm_pgtable_prot prot = pte & KVM_PTE_LEAF_ATTR_HI_SW;
427 u32 ap;
428
429 if (!kvm_pte_valid(pte))
430 return prot;
431
432 if (!(pte & KVM_PTE_LEAF_ATTR_HI_S1_XN))
433 prot |= KVM_PGTABLE_PROT_X;
434
435 ap = FIELD_GET(KVM_PTE_LEAF_ATTR_LO_S1_AP, pte);
436 if (ap == KVM_PTE_LEAF_ATTR_LO_S1_AP_RO)
437 prot |= KVM_PGTABLE_PROT_R;
438 else if (ap == KVM_PTE_LEAF_ATTR_LO_S1_AP_RW)
439 prot |= KVM_PGTABLE_PROT_RW;
440
441 return prot;
442 }
443
444 static bool hyp_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx,
445 struct hyp_map_data *data)
446 {
447 u64 phys = data->phys + (ctx->addr - ctx->start);
448 kvm_pte_t new;
449
450 if (!kvm_block_mapping_supported(ctx, phys))
451 return false;
452
453 new = kvm_init_valid_leaf_pte(phys, data->attr, ctx->level);
454 if (ctx->old == new)
455 return true;
456 if (!kvm_pte_valid(ctx->old))
457 ctx->mm_ops->get_page(ctx->ptep);
458 else if (WARN_ON((ctx->old ^ new) & ~KVM_PTE_LEAF_ATTR_HI_SW))
459 return false;
460
461 smp_store_release(ctx->ptep, new);
462 return true;
463 }
464
465 static int hyp_map_walker(const struct kvm_pgtable_visit_ctx *ctx,
466 enum kvm_pgtable_walk_flags visit)
467 {
468 kvm_pte_t *childp, new;
469 struct hyp_map_data *data = ctx->arg;
470 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
471
472 if (hyp_map_walker_try_leaf(ctx, data))
473 return 0;
474
475 if (WARN_ON(ctx->level == KVM_PGTABLE_LAST_LEVEL))
476 return -EINVAL;
477
478 childp = (kvm_pte_t *)mm_ops->zalloc_page(NULL);
479 if (!childp)
480 return -ENOMEM;
481
482 new = kvm_init_table_pte(childp, mm_ops);
483 mm_ops->get_page(ctx->ptep);
484 smp_store_release(ctx->ptep, new);
485
486 return 0;
487 }
488
489 int kvm_pgtable_hyp_map(struct kvm_pgtable *pgt, u64 addr, u64 size, u64 phys,
490 enum kvm_pgtable_prot prot)
491 {
492 int ret;
493 struct hyp_map_data map_data = {
494 .phys = ALIGN_DOWN(phys, PAGE_SIZE),
495 };
496 struct kvm_pgtable_walker walker = {
497 .cb = hyp_map_walker,
498 .flags = KVM_PGTABLE_WALK_LEAF,
499 .arg = &map_data,
500 };
501
502 ret = hyp_set_prot_attr(prot, &map_data.attr);
503 if (ret)
504 return ret;
505
506 ret = kvm_pgtable_walk(pgt, addr, size, &walker);
507 dsb(ishst);
508 isb();
509 return ret;
510 }
511
512 static int hyp_unmap_walker(const struct kvm_pgtable_visit_ctx *ctx,
513 enum kvm_pgtable_walk_flags visit)
514 {
515 kvm_pte_t *childp = NULL;
516 u64 granule = kvm_granule_size(ctx->level);
517 u64 *unmapped = ctx->arg;
518 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
519
520 if (!kvm_pte_valid(ctx->old))
521 return -EINVAL;
522
523 if (kvm_pte_table(ctx->old, ctx->level)) {
524 childp = kvm_pte_follow(ctx->old, mm_ops);
525
526 if (mm_ops->page_count(childp) != 1)
527 return 0;
528
529 kvm_clear_pte(ctx->ptep);
530 dsb(ishst);
531 __tlbi_level(vae2is, __TLBI_VADDR(ctx->addr, 0), TLBI_TTL_UNKNOWN);
532 } else {
533 if (ctx->end - ctx->addr < granule)
534 return -EINVAL;
535
536 kvm_clear_pte(ctx->ptep);
537 dsb(ishst);
538 __tlbi_level(vale2is, __TLBI_VADDR(ctx->addr, 0), ctx->level);
539 *unmapped += granule;
540 }
541
542 dsb(ish);
543 isb();
544 mm_ops->put_page(ctx->ptep);
545
546 if (childp)
547 mm_ops->put_page(childp);
548
549 return 0;
550 }
551
552 u64 kvm_pgtable_hyp_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size)
553 {
554 u64 unmapped = 0;
555 struct kvm_pgtable_walker walker = {
556 .cb = hyp_unmap_walker,
557 .arg = &unmapped,
558 .flags = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST,
559 };
560
561 if (!pgt->mm_ops->page_count)
562 return 0;
563
564 kvm_pgtable_walk(pgt, addr, size, &walker);
565 return unmapped;
566 }
567
568 int kvm_pgtable_hyp_init(struct kvm_pgtable *pgt, u32 va_bits,
569 struct kvm_pgtable_mm_ops *mm_ops)
570 {
571 s8 start_level = KVM_PGTABLE_LAST_LEVEL + 1 -
572 ARM64_HW_PGTABLE_LEVELS(va_bits);
573
574 if (start_level < KVM_PGTABLE_FIRST_LEVEL ||
575 start_level > KVM_PGTABLE_LAST_LEVEL)
576 return -EINVAL;
577
578 pgt->pgd = (kvm_pteref_t)mm_ops->zalloc_page(NULL);
579 if (!pgt->pgd)
580 return -ENOMEM;
581
582 pgt->ia_bits = va_bits;
583 pgt->start_level = start_level;
584 pgt->mm_ops = mm_ops;
585 pgt->mmu = NULL;
586 pgt->force_pte_cb = NULL;
587
588 return 0;
589 }
590
591 static int hyp_free_walker(const struct kvm_pgtable_visit_ctx *ctx,
592 enum kvm_pgtable_walk_flags visit)
593 {
594 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
595
596 if (!kvm_pte_valid(ctx->old))
597 return 0;
598
599 mm_ops->put_page(ctx->ptep);
600
601 if (kvm_pte_table(ctx->old, ctx->level))
602 mm_ops->put_page(kvm_pte_follow(ctx->old, mm_ops));
603
604 return 0;
605 }
606
607 void kvm_pgtable_hyp_destroy(struct kvm_pgtable *pgt)
608 {
609 struct kvm_pgtable_walker walker = {
610 .cb = hyp_free_walker,
611 .flags = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST,
612 };
613
614 WARN_ON(kvm_pgtable_walk(pgt, 0, BIT(pgt->ia_bits), &walker));
615 pgt->mm_ops->put_page(kvm_dereference_pteref(&walker, pgt->pgd));
616 pgt->pgd = NULL;
617 }
618
619 struct stage2_map_data {
620 const u64 phys;
621 kvm_pte_t attr;
622 u8 owner_id;
623
624 kvm_pte_t *anchor;
625 kvm_pte_t *childp;
626
627 struct kvm_s2_mmu *mmu;
628 void *memcache;
629
630 /* Force mappings to page granularity */
631 bool force_pte;
632 };
633
634 u64 kvm_get_vtcr(u64 mmfr0, u64 mmfr1, u32 phys_shift)
635 {
636 u64 vtcr = VTCR_EL2_FLAGS;
637 s8 lvls;
638
639 vtcr |= kvm_get_parange(mmfr0) << VTCR_EL2_PS_SHIFT;
640 vtcr |= VTCR_EL2_T0SZ(phys_shift);
641 /*
642 * Use a minimum 2 level page table to prevent splitting
643 * host PMD huge pages at stage2.
644 */
645 lvls = stage2_pgtable_levels(phys_shift);
646 if (lvls < 2)
647 lvls = 2;
648
649 /*
650 * When LPA2 is enabled, the HW supports an extra level of translation
651 * (for 5 in total) when using 4K pages. It also introduces VTCR_EL2.SL2
652 * to as an addition to SL0 to enable encoding this extra start level.
653 * However, since we always use concatenated pages for the first level
654 * lookup, we will never need this extra level and therefore do not need
655 * to touch SL2.
656 */
657 vtcr |= VTCR_EL2_LVLS_TO_SL0(lvls);
658
659 #ifdef CONFIG_ARM64_HW_AFDBM
660 /*
661 * Enable the Hardware Access Flag management, unconditionally
662 * on all CPUs. In systems that have asymmetric support for the feature
663 * this allows KVM to leverage hardware support on the subset of cores
664 * that implement the feature.
665 *
666 * The architecture requires VTCR_EL2.HA to be RES0 (thus ignored by
667 * hardware) on implementations that do not advertise support for the
668 * feature. As such, setting HA unconditionally is safe, unless you
669 * happen to be running on a design that has unadvertised support for
670 * HAFDBS. Here be dragons.
671 */
672 if (!cpus_have_final_cap(ARM64_WORKAROUND_AMPERE_AC03_CPU_38))
673 vtcr |= VTCR_EL2_HA;
674 #endif /* CONFIG_ARM64_HW_AFDBM */
675
676 if (kvm_lpa2_is_enabled())
677 vtcr |= VTCR_EL2_DS;
678
679 /* Set the vmid bits */
680 vtcr |= (get_vmid_bits(mmfr1) == 16) ?
681 VTCR_EL2_VS_16BIT :
682 VTCR_EL2_VS_8BIT;
683
684 return vtcr;
685 }
686
687 static bool stage2_has_fwb(struct kvm_pgtable *pgt)
688 {
689 if (!cpus_have_final_cap(ARM64_HAS_STAGE2_FWB))
690 return false;
691
692 return !(pgt->flags & KVM_PGTABLE_S2_NOFWB);
693 }
694
695 void kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
696 phys_addr_t addr, size_t size)
697 {
698 unsigned long pages, inval_pages;
699
700 if (!system_supports_tlb_range()) {
701 kvm_call_hyp(__kvm_tlb_flush_vmid, mmu);
702 return;
703 }
704
705 pages = size >> PAGE_SHIFT;
706 while (pages > 0) {
707 inval_pages = min(pages, MAX_TLBI_RANGE_PAGES);
708 kvm_call_hyp(__kvm_tlb_flush_vmid_range, mmu, addr, inval_pages);
709
710 addr += inval_pages << PAGE_SHIFT;
711 pages -= inval_pages;
712 }
713 }
714
715 #define KVM_S2_MEMATTR(pgt, attr) PAGE_S2_MEMATTR(attr, stage2_has_fwb(pgt))
716
717 static int stage2_set_prot_attr(struct kvm_pgtable *pgt, enum kvm_pgtable_prot prot,
718 kvm_pte_t *ptep)
719 {
720 kvm_pte_t attr;
721 u32 sh = KVM_PTE_LEAF_ATTR_LO_S2_SH_IS;
722
723 switch (prot & (KVM_PGTABLE_PROT_DEVICE |
724 KVM_PGTABLE_PROT_NORMAL_NC)) {
725 case KVM_PGTABLE_PROT_DEVICE | KVM_PGTABLE_PROT_NORMAL_NC:
726 return -EINVAL;
727 case KVM_PGTABLE_PROT_DEVICE:
728 if (prot & KVM_PGTABLE_PROT_X)
729 return -EINVAL;
730 attr = KVM_S2_MEMATTR(pgt, DEVICE_nGnRE);
731 break;
732 case KVM_PGTABLE_PROT_NORMAL_NC:
733 if (prot & KVM_PGTABLE_PROT_X)
734 return -EINVAL;
735 attr = KVM_S2_MEMATTR(pgt, NORMAL_NC);
736 break;
737 default:
738 attr = KVM_S2_MEMATTR(pgt, NORMAL);
739 }
740
741 if (!(prot & KVM_PGTABLE_PROT_X))
742 attr |= KVM_PTE_LEAF_ATTR_HI_S2_XN;
743
744 if (prot & KVM_PGTABLE_PROT_R)
745 attr |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R;
746
747 if (prot & KVM_PGTABLE_PROT_W)
748 attr |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W;
749
750 if (!kvm_lpa2_is_enabled())
751 attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S2_SH, sh);
752
753 attr |= KVM_PTE_LEAF_ATTR_LO_S2_AF;
754 attr |= prot & KVM_PTE_LEAF_ATTR_HI_SW;
755 *ptep = attr;
756
757 return 0;
758 }
759
760 enum kvm_pgtable_prot kvm_pgtable_stage2_pte_prot(kvm_pte_t pte)
761 {
762 enum kvm_pgtable_prot prot = pte & KVM_PTE_LEAF_ATTR_HI_SW;
763
764 if (!kvm_pte_valid(pte))
765 return prot;
766
767 if (pte & KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R)
768 prot |= KVM_PGTABLE_PROT_R;
769 if (pte & KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W)
770 prot |= KVM_PGTABLE_PROT_W;
771 if (!(pte & KVM_PTE_LEAF_ATTR_HI_S2_XN))
772 prot |= KVM_PGTABLE_PROT_X;
773
774 return prot;
775 }
776
777 static bool stage2_pte_needs_update(kvm_pte_t old, kvm_pte_t new)
778 {
779 if (!kvm_pte_valid(old) || !kvm_pte_valid(new))
780 return true;
781
782 return ((old ^ new) & (~KVM_PTE_LEAF_ATTR_S2_PERMS));
783 }
784
785 static bool stage2_pte_is_counted(kvm_pte_t pte)
786 {
787 /*
788 * The refcount tracks valid entries as well as invalid entries if they
789 * encode ownership of a page to another entity than the page-table
790 * owner, whose id is 0.
791 */
792 return !!pte;
793 }
794
795 static bool stage2_pte_is_locked(kvm_pte_t pte)
796 {
797 return !kvm_pte_valid(pte) && (pte & KVM_INVALID_PTE_LOCKED);
798 }
799
800 static bool stage2_try_set_pte(const struct kvm_pgtable_visit_ctx *ctx, kvm_pte_t new)
801 {
802 if (!kvm_pgtable_walk_shared(ctx)) {
803 WRITE_ONCE(*ctx->ptep, new);
804 return true;
805 }
806
807 return cmpxchg(ctx->ptep, ctx->old, new) == ctx->old;
808 }
809
810 /**
811 * stage2_try_break_pte() - Invalidates a pte according to the
812 * 'break-before-make' requirements of the
813 * architecture.
814 *
815 * @ctx: context of the visited pte.
816 * @mmu: stage-2 mmu
817 *
818 * Returns: true if the pte was successfully broken.
819 *
820 * If the removed pte was valid, performs the necessary serialization and TLB
821 * invalidation for the old value. For counted ptes, drops the reference count
822 * on the containing table page.
823 */
824 static bool stage2_try_break_pte(const struct kvm_pgtable_visit_ctx *ctx,
825 struct kvm_s2_mmu *mmu)
826 {
827 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
828
829 if (stage2_pte_is_locked(ctx->old)) {
830 /*
831 * Should never occur if this walker has exclusive access to the
832 * page tables.
833 */
834 WARN_ON(!kvm_pgtable_walk_shared(ctx));
835 return false;
836 }
837
838 if (!stage2_try_set_pte(ctx, KVM_INVALID_PTE_LOCKED))
839 return false;
840
841 if (!kvm_pgtable_walk_skip_bbm_tlbi(ctx)) {
842 /*
843 * Perform the appropriate TLB invalidation based on the
844 * evicted pte value (if any).
845 */
846 if (kvm_pte_table(ctx->old, ctx->level)) {
847 u64 size = kvm_granule_size(ctx->level);
848 u64 addr = ALIGN_DOWN(ctx->addr, size);
849
850 kvm_tlb_flush_vmid_range(mmu, addr, size);
851 } else if (kvm_pte_valid(ctx->old)) {
852 kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu,
853 ctx->addr, ctx->level);
854 }
855 }
856
857 if (stage2_pte_is_counted(ctx->old))
858 mm_ops->put_page(ctx->ptep);
859
860 return true;
861 }
862
863 static void stage2_make_pte(const struct kvm_pgtable_visit_ctx *ctx, kvm_pte_t new)
864 {
865 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
866
867 WARN_ON(!stage2_pte_is_locked(*ctx->ptep));
868
869 if (stage2_pte_is_counted(new))
870 mm_ops->get_page(ctx->ptep);
871
872 smp_store_release(ctx->ptep, new);
873 }
874
875 static bool stage2_unmap_defer_tlb_flush(struct kvm_pgtable *pgt)
876 {
877 /*
878 * If FEAT_TLBIRANGE is implemented, defer the individual
879 * TLB invalidations until the entire walk is finished, and
880 * then use the range-based TLBI instructions to do the
881 * invalidations. Condition deferred TLB invalidation on the
882 * system supporting FWB as the optimization is entirely
883 * pointless when the unmap walker needs to perform CMOs.
884 */
885 return system_supports_tlb_range() && stage2_has_fwb(pgt);
886 }
887
888 static void stage2_unmap_put_pte(const struct kvm_pgtable_visit_ctx *ctx,
889 struct kvm_s2_mmu *mmu,
890 struct kvm_pgtable_mm_ops *mm_ops)
891 {
892 struct kvm_pgtable *pgt = ctx->arg;
893
894 /*
895 * Clear the existing PTE, and perform break-before-make if it was
896 * valid. Depending on the system support, defer the TLB maintenance
897 * for the same until the entire unmap walk is completed.
898 */
899 if (kvm_pte_valid(ctx->old)) {
900 kvm_clear_pte(ctx->ptep);
901
902 if (kvm_pte_table(ctx->old, ctx->level)) {
903 kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu, ctx->addr,
904 TLBI_TTL_UNKNOWN);
905 } else if (!stage2_unmap_defer_tlb_flush(pgt)) {
906 kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu, ctx->addr,
907 ctx->level);
908 }
909 }
910
911 mm_ops->put_page(ctx->ptep);
912 }
913
914 static bool stage2_pte_cacheable(struct kvm_pgtable *pgt, kvm_pte_t pte)
915 {
916 u64 memattr = pte & KVM_PTE_LEAF_ATTR_LO_S2_MEMATTR;
917 return kvm_pte_valid(pte) && memattr == KVM_S2_MEMATTR(pgt, NORMAL);
918 }
919
920 static bool stage2_pte_executable(kvm_pte_t pte)
921 {
922 return kvm_pte_valid(pte) && !(pte & KVM_PTE_LEAF_ATTR_HI_S2_XN);
923 }
924
925 static u64 stage2_map_walker_phys_addr(const struct kvm_pgtable_visit_ctx *ctx,
926 const struct stage2_map_data *data)
927 {
928 u64 phys = data->phys;
929
930 /*
931 * Stage-2 walks to update ownership data are communicated to the map
932 * walker using an invalid PA. Avoid offsetting an already invalid PA,
933 * which could overflow and make the address valid again.
934 */
935 if (!kvm_phys_is_valid(phys))
936 return phys;
937
938 /*
939 * Otherwise, work out the correct PA based on how far the walk has
940 * gotten.
941 */
942 return phys + (ctx->addr - ctx->start);
943 }
944
945 static bool stage2_leaf_mapping_allowed(const struct kvm_pgtable_visit_ctx *ctx,
946 struct stage2_map_data *data)
947 {
948 u64 phys = stage2_map_walker_phys_addr(ctx, data);
949
950 if (data->force_pte && ctx->level < KVM_PGTABLE_LAST_LEVEL)
951 return false;
952
953 return kvm_block_mapping_supported(ctx, phys);
954 }
955
956 static int stage2_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx,
957 struct stage2_map_data *data)
958 {
959 kvm_pte_t new;
960 u64 phys = stage2_map_walker_phys_addr(ctx, data);
961 u64 granule = kvm_granule_size(ctx->level);
962 struct kvm_pgtable *pgt = data->mmu->pgt;
963 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
964
965 if (!stage2_leaf_mapping_allowed(ctx, data))
966 return -E2BIG;
967
968 if (kvm_phys_is_valid(phys))
969 new = kvm_init_valid_leaf_pte(phys, data->attr, ctx->level);
970 else
971 new = kvm_init_invalid_leaf_owner(data->owner_id);
972
973 /*
974 * Skip updating the PTE if we are trying to recreate the exact
975 * same mapping or only change the access permissions. Instead,
976 * the vCPU will exit one more time from guest if still needed
977 * and then go through the path of relaxing permissions.
978 */
979 if (!stage2_pte_needs_update(ctx->old, new))
980 return -EAGAIN;
981
982 /* If we're only changing software bits, then store them and go! */
983 if (!kvm_pgtable_walk_shared(ctx) &&
984 !((ctx->old ^ new) & ~KVM_PTE_LEAF_ATTR_HI_SW)) {
985 bool old_is_counted = stage2_pte_is_counted(ctx->old);
986
987 if (old_is_counted != stage2_pte_is_counted(new)) {
988 if (old_is_counted)
989 mm_ops->put_page(ctx->ptep);
990 else
991 mm_ops->get_page(ctx->ptep);
992 }
993 WARN_ON_ONCE(!stage2_try_set_pte(ctx, new));
994 return 0;
995 }
996
997 if (!stage2_try_break_pte(ctx, data->mmu))
998 return -EAGAIN;
999
1000 /* Perform CMOs before installation of the guest stage-2 PTE */
1001 if (!kvm_pgtable_walk_skip_cmo(ctx) && mm_ops->dcache_clean_inval_poc &&
1002 stage2_pte_cacheable(pgt, new))
1003 mm_ops->dcache_clean_inval_poc(kvm_pte_follow(new, mm_ops),
1004 granule);
1005
1006 if (!kvm_pgtable_walk_skip_cmo(ctx) && mm_ops->icache_inval_pou &&
1007 stage2_pte_executable(new))
1008 mm_ops->icache_inval_pou(kvm_pte_follow(new, mm_ops), granule);
1009
1010 stage2_make_pte(ctx, new);
1011
1012 return 0;
1013 }
1014
1015 static int stage2_map_walk_table_pre(const struct kvm_pgtable_visit_ctx *ctx,
1016 struct stage2_map_data *data)
1017 {
1018 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
1019 kvm_pte_t *childp = kvm_pte_follow(ctx->old, mm_ops);
1020 int ret;
1021
1022 if (!stage2_leaf_mapping_allowed(ctx, data))
1023 return 0;
1024
1025 ret = stage2_map_walker_try_leaf(ctx, data);
1026 if (ret)
1027 return ret;
1028
1029 mm_ops->free_unlinked_table(childp, ctx->level);
1030 return 0;
1031 }
1032
1033 static int stage2_map_walk_leaf(const struct kvm_pgtable_visit_ctx *ctx,
1034 struct stage2_map_data *data)
1035 {
1036 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
1037 kvm_pte_t *childp, new;
1038 int ret;
1039
1040 ret = stage2_map_walker_try_leaf(ctx, data);
1041 if (ret != -E2BIG)
1042 return ret;
1043
1044 if (WARN_ON(ctx->level == KVM_PGTABLE_LAST_LEVEL))
1045 return -EINVAL;
1046
1047 if (!data->memcache)
1048 return -ENOMEM;
1049
1050 childp = mm_ops->zalloc_page(data->memcache);
1051 if (!childp)
1052 return -ENOMEM;
1053
1054 if (!stage2_try_break_pte(ctx, data->mmu)) {
1055 mm_ops->put_page(childp);
1056 return -EAGAIN;
1057 }
1058
1059 /*
1060 * If we've run into an existing block mapping then replace it with
1061 * a table. Accesses beyond 'end' that fall within the new table
1062 * will be mapped lazily.
1063 */
1064 new = kvm_init_table_pte(childp, mm_ops);
1065 stage2_make_pte(ctx, new);
1066
1067 return 0;
1068 }
1069
1070 /*
1071 * The TABLE_PRE callback runs for table entries on the way down, looking
1072 * for table entries which we could conceivably replace with a block entry
1073 * for this mapping. If it finds one it replaces the entry and calls
1074 * kvm_pgtable_mm_ops::free_unlinked_table() to tear down the detached table.
1075 *
1076 * Otherwise, the LEAF callback performs the mapping at the existing leaves
1077 * instead.
1078 */
1079 static int stage2_map_walker(const struct kvm_pgtable_visit_ctx *ctx,
1080 enum kvm_pgtable_walk_flags visit)
1081 {
1082 struct stage2_map_data *data = ctx->arg;
1083
1084 switch (visit) {
1085 case KVM_PGTABLE_WALK_TABLE_PRE:
1086 return stage2_map_walk_table_pre(ctx, data);
1087 case KVM_PGTABLE_WALK_LEAF:
1088 return stage2_map_walk_leaf(ctx, data);
1089 default:
1090 return -EINVAL;
1091 }
1092 }
1093
1094 int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
1095 u64 phys, enum kvm_pgtable_prot prot,
1096 void *mc, enum kvm_pgtable_walk_flags flags)
1097 {
1098 int ret;
1099 struct stage2_map_data map_data = {
1100 .phys = ALIGN_DOWN(phys, PAGE_SIZE),
1101 .mmu = pgt->mmu,
1102 .memcache = mc,
1103 .force_pte = pgt->force_pte_cb && pgt->force_pte_cb(addr, addr + size, prot),
1104 };
1105 struct kvm_pgtable_walker walker = {
1106 .cb = stage2_map_walker,
1107 .flags = flags |
1108 KVM_PGTABLE_WALK_TABLE_PRE |
1109 KVM_PGTABLE_WALK_LEAF,
1110 .arg = &map_data,
1111 };
1112
1113 if (WARN_ON((pgt->flags & KVM_PGTABLE_S2_IDMAP) && (addr != phys)))
1114 return -EINVAL;
1115
1116 ret = stage2_set_prot_attr(pgt, prot, &map_data.attr);
1117 if (ret)
1118 return ret;
1119
1120 ret = kvm_pgtable_walk(pgt, addr, size, &walker);
1121 dsb(ishst);
1122 return ret;
1123 }
1124
1125 int kvm_pgtable_stage2_set_owner(struct kvm_pgtable *pgt, u64 addr, u64 size,
1126 void *mc, u8 owner_id)
1127 {
1128 int ret;
1129 struct stage2_map_data map_data = {
1130 .phys = KVM_PHYS_INVALID,
1131 .mmu = pgt->mmu,
1132 .memcache = mc,
1133 .owner_id = owner_id,
1134 .force_pte = true,
1135 };
1136 struct kvm_pgtable_walker walker = {
1137 .cb = stage2_map_walker,
1138 .flags = KVM_PGTABLE_WALK_TABLE_PRE |
1139 KVM_PGTABLE_WALK_LEAF,
1140 .arg = &map_data,
1141 };
1142
1143 if (owner_id > KVM_MAX_OWNER_ID)
1144 return -EINVAL;
1145
1146 ret = kvm_pgtable_walk(pgt, addr, size, &walker);
1147 return ret;
1148 }
1149
1150 static int stage2_unmap_walker(const struct kvm_pgtable_visit_ctx *ctx,
1151 enum kvm_pgtable_walk_flags visit)
1152 {
1153 struct kvm_pgtable *pgt = ctx->arg;
1154 struct kvm_s2_mmu *mmu = pgt->mmu;
1155 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
1156 kvm_pte_t *childp = NULL;
1157 bool need_flush = false;
1158
1159 if (!kvm_pte_valid(ctx->old)) {
1160 if (stage2_pte_is_counted(ctx->old)) {
1161 kvm_clear_pte(ctx->ptep);
1162 mm_ops->put_page(ctx->ptep);
1163 }
1164 return 0;
1165 }
1166
1167 if (kvm_pte_table(ctx->old, ctx->level)) {
1168 childp = kvm_pte_follow(ctx->old, mm_ops);
1169
1170 if (mm_ops->page_count(childp) != 1)
1171 return 0;
1172 } else if (stage2_pte_cacheable(pgt, ctx->old)) {
1173 need_flush = !stage2_has_fwb(pgt);
1174 }
1175
1176 /*
1177 * This is similar to the map() path in that we unmap the entire
1178 * block entry and rely on the remaining portions being faulted
1179 * back lazily.
1180 */
1181 stage2_unmap_put_pte(ctx, mmu, mm_ops);
1182
1183 if (need_flush && mm_ops->dcache_clean_inval_poc)
1184 mm_ops->dcache_clean_inval_poc(kvm_pte_follow(ctx->old, mm_ops),
1185 kvm_granule_size(ctx->level));
1186
1187 if (childp)
1188 mm_ops->put_page(childp);
1189
1190 return 0;
1191 }
1192
1193 int kvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size)
1194 {
1195 int ret;
1196 struct kvm_pgtable_walker walker = {
1197 .cb = stage2_unmap_walker,
1198 .arg = pgt,
1199 .flags = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST,
1200 };
1201
1202 ret = kvm_pgtable_walk(pgt, addr, size, &walker);
1203 if (stage2_unmap_defer_tlb_flush(pgt))
1204 /* Perform the deferred TLB invalidations */
1205 kvm_tlb_flush_vmid_range(pgt->mmu, addr, size);
1206
1207 return ret;
1208 }
1209
1210 struct stage2_attr_data {
1211 kvm_pte_t attr_set;
1212 kvm_pte_t attr_clr;
1213 kvm_pte_t pte;
1214 s8 level;
1215 };
1216
1217 static int stage2_attr_walker(const struct kvm_pgtable_visit_ctx *ctx,
1218 enum kvm_pgtable_walk_flags visit)
1219 {
1220 kvm_pte_t pte = ctx->old;
1221 struct stage2_attr_data *data = ctx->arg;
1222 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
1223
1224 if (!kvm_pte_valid(ctx->old))
1225 return -EAGAIN;
1226
1227 data->level = ctx->level;
1228 data->pte = pte;
1229 pte &= ~data->attr_clr;
1230 pte |= data->attr_set;
1231
1232 /*
1233 * We may race with the CPU trying to set the access flag here,
1234 * but worst-case the access flag update gets lost and will be
1235 * set on the next access instead.
1236 */
1237 if (data->pte != pte) {
1238 /*
1239 * Invalidate instruction cache before updating the guest
1240 * stage-2 PTE if we are going to add executable permission.
1241 */
1242 if (mm_ops->icache_inval_pou &&
1243 stage2_pte_executable(pte) && !stage2_pte_executable(ctx->old))
1244 mm_ops->icache_inval_pou(kvm_pte_follow(pte, mm_ops),
1245 kvm_granule_size(ctx->level));
1246
1247 if (!stage2_try_set_pte(ctx, pte))
1248 return -EAGAIN;
1249 }
1250
1251 return 0;
1252 }
1253
1254 static int stage2_update_leaf_attrs(struct kvm_pgtable *pgt, u64 addr,
1255 u64 size, kvm_pte_t attr_set,
1256 kvm_pte_t attr_clr, kvm_pte_t *orig_pte,
1257 s8 *level, enum kvm_pgtable_walk_flags flags)
1258 {
1259 int ret;
1260 kvm_pte_t attr_mask = KVM_PTE_LEAF_ATTR_LO | KVM_PTE_LEAF_ATTR_HI;
1261 struct stage2_attr_data data = {
1262 .attr_set = attr_set & attr_mask,
1263 .attr_clr = attr_clr & attr_mask,
1264 };
1265 struct kvm_pgtable_walker walker = {
1266 .cb = stage2_attr_walker,
1267 .arg = &data,
1268 .flags = flags | KVM_PGTABLE_WALK_LEAF,
1269 };
1270
1271 ret = kvm_pgtable_walk(pgt, addr, size, &walker);
1272 if (ret)
1273 return ret;
1274
1275 if (orig_pte)
1276 *orig_pte = data.pte;
1277
1278 if (level)
1279 *level = data.level;
1280 return 0;
1281 }
1282
1283 int kvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size)
1284 {
1285 return stage2_update_leaf_attrs(pgt, addr, size, 0,
1286 KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W,
1287 NULL, NULL, 0);
1288 }
1289
1290 kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr)
1291 {
1292 kvm_pte_t pte = 0;
1293 int ret;
1294
1295 ret = stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0,
1296 &pte, NULL,
1297 KVM_PGTABLE_WALK_HANDLE_FAULT |
1298 KVM_PGTABLE_WALK_SHARED);
1299 if (!ret)
1300 dsb(ishst);
1301
1302 return pte;
1303 }
1304
1305 struct stage2_age_data {
1306 bool mkold;
1307 bool young;
1308 };
1309
1310 static int stage2_age_walker(const struct kvm_pgtable_visit_ctx *ctx,
1311 enum kvm_pgtable_walk_flags visit)
1312 {
1313 kvm_pte_t new = ctx->old & ~KVM_PTE_LEAF_ATTR_LO_S2_AF;
1314 struct stage2_age_data *data = ctx->arg;
1315
1316 if (!kvm_pte_valid(ctx->old) || new == ctx->old)
1317 return 0;
1318
1319 data->young = true;
1320
1321 /*
1322 * stage2_age_walker() is always called while holding the MMU lock for
1323 * write, so this will always succeed. Nonetheless, this deliberately
1324 * follows the race detection pattern of the other stage-2 walkers in
1325 * case the locking mechanics of the MMU notifiers is ever changed.
1326 */
1327 if (data->mkold && !stage2_try_set_pte(ctx, new))
1328 return -EAGAIN;
1329
1330 /*
1331 * "But where's the TLBI?!", you scream.
1332 * "Over in the core code", I sigh.
1333 *
1334 * See the '->clear_flush_young()' callback on the KVM mmu notifier.
1335 */
1336 return 0;
1337 }
1338
1339 bool kvm_pgtable_stage2_test_clear_young(struct kvm_pgtable *pgt, u64 addr,
1340 u64 size, bool mkold)
1341 {
1342 struct stage2_age_data data = {
1343 .mkold = mkold,
1344 };
1345 struct kvm_pgtable_walker walker = {
1346 .cb = stage2_age_walker,
1347 .arg = &data,
1348 .flags = KVM_PGTABLE_WALK_LEAF,
1349 };
1350
1351 WARN_ON(kvm_pgtable_walk(pgt, addr, size, &walker));
1352 return data.young;
1353 }
1354
1355 int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr,
1356 enum kvm_pgtable_prot prot)
1357 {
1358 int ret;
1359 s8 level;
1360 kvm_pte_t set = 0, clr = 0;
1361
1362 if (prot & KVM_PTE_LEAF_ATTR_HI_SW)
1363 return -EINVAL;
1364
1365 if (prot & KVM_PGTABLE_PROT_R)
1366 set |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R;
1367
1368 if (prot & KVM_PGTABLE_PROT_W)
1369 set |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W;
1370
1371 if (prot & KVM_PGTABLE_PROT_X)
1372 clr |= KVM_PTE_LEAF_ATTR_HI_S2_XN;
1373
1374 ret = stage2_update_leaf_attrs(pgt, addr, 1, set, clr, NULL, &level,
1375 KVM_PGTABLE_WALK_HANDLE_FAULT |
1376 KVM_PGTABLE_WALK_SHARED);
1377 if (!ret || ret == -EAGAIN)
1378 kvm_call_hyp(__kvm_tlb_flush_vmid_ipa_nsh, pgt->mmu, addr, level);
1379 return ret;
1380 }
1381
1382 static int stage2_flush_walker(const struct kvm_pgtable_visit_ctx *ctx,
1383 enum kvm_pgtable_walk_flags visit)
1384 {
1385 struct kvm_pgtable *pgt = ctx->arg;
1386 struct kvm_pgtable_mm_ops *mm_ops = pgt->mm_ops;
1387
1388 if (!stage2_pte_cacheable(pgt, ctx->old))
1389 return 0;
1390
1391 if (mm_ops->dcache_clean_inval_poc)
1392 mm_ops->dcache_clean_inval_poc(kvm_pte_follow(ctx->old, mm_ops),
1393 kvm_granule_size(ctx->level));
1394 return 0;
1395 }
1396
1397 int kvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size)
1398 {
1399 struct kvm_pgtable_walker walker = {
1400 .cb = stage2_flush_walker,
1401 .flags = KVM_PGTABLE_WALK_LEAF,
1402 .arg = pgt,
1403 };
1404
1405 if (stage2_has_fwb(pgt))
1406 return 0;
1407
1408 return kvm_pgtable_walk(pgt, addr, size, &walker);
1409 }
1410
1411 kvm_pte_t *kvm_pgtable_stage2_create_unlinked(struct kvm_pgtable *pgt,
1412 u64 phys, s8 level,
1413 enum kvm_pgtable_prot prot,
1414 void *mc, bool force_pte)
1415 {
1416 struct stage2_map_data map_data = {
1417 .phys = phys,
1418 .mmu = pgt->mmu,
1419 .memcache = mc,
1420 .force_pte = force_pte,
1421 };
1422 struct kvm_pgtable_walker walker = {
1423 .cb = stage2_map_walker,
1424 .flags = KVM_PGTABLE_WALK_LEAF |
1425 KVM_PGTABLE_WALK_SKIP_BBM_TLBI |
1426 KVM_PGTABLE_WALK_SKIP_CMO,
1427 .arg = &map_data,
1428 };
1429 /*
1430 * The input address (.addr) is irrelevant for walking an
1431 * unlinked table. Construct an ambiguous IA range to map
1432 * kvm_granule_size(level) worth of memory.
1433 */
1434 struct kvm_pgtable_walk_data data = {
1435 .walker = &walker,
1436 .addr = 0,
1437 .end = kvm_granule_size(level),
1438 };
1439 struct kvm_pgtable_mm_ops *mm_ops = pgt->mm_ops;
1440 kvm_pte_t *pgtable;
1441 int ret;
1442
1443 if (!IS_ALIGNED(phys, kvm_granule_size(level)))
1444 return ERR_PTR(-EINVAL);
1445
1446 ret = stage2_set_prot_attr(pgt, prot, &map_data.attr);
1447 if (ret)
1448 return ERR_PTR(ret);
1449
1450 pgtable = mm_ops->zalloc_page(mc);
1451 if (!pgtable)
1452 return ERR_PTR(-ENOMEM);
1453
1454 ret = __kvm_pgtable_walk(&data, mm_ops, (kvm_pteref_t)pgtable,
1455 level + 1);
1456 if (ret) {
1457 kvm_pgtable_stage2_free_unlinked(mm_ops, pgtable, level);
1458 return ERR_PTR(ret);
1459 }
1460
1461 return pgtable;
1462 }
1463
1464 /*
1465 * Get the number of page-tables needed to replace a block with a
1466 * fully populated tree up to the PTE entries. Note that @level is
1467 * interpreted as in "level @level entry".
1468 */
1469 static int stage2_block_get_nr_page_tables(s8 level)
1470 {
1471 switch (level) {
1472 case 1:
1473 return PTRS_PER_PTE + 1;
1474 case 2:
1475 return 1;
1476 case 3:
1477 return 0;
1478 default:
1479 WARN_ON_ONCE(level < KVM_PGTABLE_MIN_BLOCK_LEVEL ||
1480 level > KVM_PGTABLE_LAST_LEVEL);
1481 return -EINVAL;
1482 };
1483 }
1484
1485 static int stage2_split_walker(const struct kvm_pgtable_visit_ctx *ctx,
1486 enum kvm_pgtable_walk_flags visit)
1487 {
1488 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
1489 struct kvm_mmu_memory_cache *mc = ctx->arg;
1490 struct kvm_s2_mmu *mmu;
1491 kvm_pte_t pte = ctx->old, new, *childp;
1492 enum kvm_pgtable_prot prot;
1493 s8 level = ctx->level;
1494 bool force_pte;
1495 int nr_pages;
1496 u64 phys;
1497
1498 /* No huge-pages exist at the last level */
1499 if (level == KVM_PGTABLE_LAST_LEVEL)
1500 return 0;
1501
1502 /* We only split valid block mappings */
1503 if (!kvm_pte_valid(pte))
1504 return 0;
1505
1506 nr_pages = stage2_block_get_nr_page_tables(level);
1507 if (nr_pages < 0)
1508 return nr_pages;
1509
1510 if (mc->nobjs >= nr_pages) {
1511 /* Build a tree mapped down to the PTE granularity. */
1512 force_pte = true;
1513 } else {
1514 /*
1515 * Don't force PTEs, so create_unlinked() below does
1516 * not populate the tree up to the PTE level. The
1517 * consequence is that the call will require a single
1518 * page of level 2 entries at level 1, or a single
1519 * page of PTEs at level 2. If we are at level 1, the
1520 * PTEs will be created recursively.
1521 */
1522 force_pte = false;
1523 nr_pages = 1;
1524 }
1525
1526 if (mc->nobjs < nr_pages)
1527 return -ENOMEM;
1528
1529 mmu = container_of(mc, struct kvm_s2_mmu, split_page_cache);
1530 phys = kvm_pte_to_phys(pte);
1531 prot = kvm_pgtable_stage2_pte_prot(pte);
1532
1533 childp = kvm_pgtable_stage2_create_unlinked(mmu->pgt, phys,
1534 level, prot, mc, force_pte);
1535 if (IS_ERR(childp))
1536 return PTR_ERR(childp);
1537
1538 if (!stage2_try_break_pte(ctx, mmu)) {
1539 kvm_pgtable_stage2_free_unlinked(mm_ops, childp, level);
1540 return -EAGAIN;
1541 }
1542
1543 /*
1544 * Note, the contents of the page table are guaranteed to be made
1545 * visible before the new PTE is assigned because stage2_make_pte()
1546 * writes the PTE using smp_store_release().
1547 */
1548 new = kvm_init_table_pte(childp, mm_ops);
1549 stage2_make_pte(ctx, new);
1550 dsb(ishst);
1551 return 0;
1552 }
1553
1554 int kvm_pgtable_stage2_split(struct kvm_pgtable *pgt, u64 addr, u64 size,
1555 struct kvm_mmu_memory_cache *mc)
1556 {
1557 struct kvm_pgtable_walker walker = {
1558 .cb = stage2_split_walker,
1559 .flags = KVM_PGTABLE_WALK_LEAF,
1560 .arg = mc,
1561 };
1562
1563 return kvm_pgtable_walk(pgt, addr, size, &walker);
1564 }
1565
1566 int __kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu,
1567 struct kvm_pgtable_mm_ops *mm_ops,
1568 enum kvm_pgtable_stage2_flags flags,
1569 kvm_pgtable_force_pte_cb_t force_pte_cb)
1570 {
1571 size_t pgd_sz;
1572 u64 vtcr = mmu->vtcr;
1573 u32 ia_bits = VTCR_EL2_IPA(vtcr);
1574 u32 sl0 = FIELD_GET(VTCR_EL2_SL0_MASK, vtcr);
1575 s8 start_level = VTCR_EL2_TGRAN_SL0_BASE - sl0;
1576
1577 pgd_sz = kvm_pgd_pages(ia_bits, start_level) * PAGE_SIZE;
1578 pgt->pgd = (kvm_pteref_t)mm_ops->zalloc_pages_exact(pgd_sz);
1579 if (!pgt->pgd)
1580 return -ENOMEM;
1581
1582 pgt->ia_bits = ia_bits;
1583 pgt->start_level = start_level;
1584 pgt->mm_ops = mm_ops;
1585 pgt->mmu = mmu;
1586 pgt->flags = flags;
1587 pgt->force_pte_cb = force_pte_cb;
1588
1589 /* Ensure zeroed PGD pages are visible to the hardware walker */
1590 dsb(ishst);
1591 return 0;
1592 }
1593
1594 size_t kvm_pgtable_stage2_pgd_size(u64 vtcr)
1595 {
1596 u32 ia_bits = VTCR_EL2_IPA(vtcr);
1597 u32 sl0 = FIELD_GET(VTCR_EL2_SL0_MASK, vtcr);
1598 s8 start_level = VTCR_EL2_TGRAN_SL0_BASE - sl0;
1599
1600 return kvm_pgd_pages(ia_bits, start_level) * PAGE_SIZE;
1601 }
1602
1603 static int stage2_free_walker(const struct kvm_pgtable_visit_ctx *ctx,
1604 enum kvm_pgtable_walk_flags visit)
1605 {
1606 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
1607
1608 if (!stage2_pte_is_counted(ctx->old))
1609 return 0;
1610
1611 mm_ops->put_page(ctx->ptep);
1612
1613 if (kvm_pte_table(ctx->old, ctx->level))
1614 mm_ops->put_page(kvm_pte_follow(ctx->old, mm_ops));
1615
1616 return 0;
1617 }
1618
1619 void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt)
1620 {
1621 size_t pgd_sz;
1622 struct kvm_pgtable_walker walker = {
1623 .cb = stage2_free_walker,
1624 .flags = KVM_PGTABLE_WALK_LEAF |
1625 KVM_PGTABLE_WALK_TABLE_POST,
1626 };
1627
1628 WARN_ON(kvm_pgtable_walk(pgt, 0, BIT(pgt->ia_bits), &walker));
1629 pgd_sz = kvm_pgd_pages(pgt->ia_bits, pgt->start_level) * PAGE_SIZE;
1630 pgt->mm_ops->free_pages_exact(kvm_dereference_pteref(&walker, pgt->pgd), pgd_sz);
1631 pgt->pgd = NULL;
1632 }
1633
1634 void kvm_pgtable_stage2_free_unlinked(struct kvm_pgtable_mm_ops *mm_ops, void *pgtable, s8 level)
1635 {
1636 kvm_pteref_t ptep = (kvm_pteref_t)pgtable;
1637 struct kvm_pgtable_walker walker = {
1638 .cb = stage2_free_walker,
1639 .flags = KVM_PGTABLE_WALK_LEAF |
1640 KVM_PGTABLE_WALK_TABLE_POST,
1641 };
1642 struct kvm_pgtable_walk_data data = {
1643 .walker = &walker,
1644
1645 /*
1646 * At this point the IPA really doesn't matter, as the page
1647 * table being traversed has already been removed from the stage
1648 * 2. Set an appropriate range to cover the entire page table.
1649 */
1650 .addr = 0,
1651 .end = kvm_granule_size(level),
1652 };
1653
1654 WARN_ON(__kvm_pgtable_walk(&data, mm_ops, ptep, level + 1));
1655
1656 WARN_ON(mm_ops->page_count(pgtable) != 1);
1657 mm_ops->put_page(pgtable);
1658 }
1659
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