]> Git Repo - linux.git/blob - arch/arm64/kvm/hyp/pgtable.c
Merge tag 'amd-drm-next-6.5-2023-06-09' of https://gitlab.freedesktop.org/agd5f/linux...
[linux.git] / arch / arm64 / kvm / hyp / pgtable.c
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 <[email protected]>
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   3
25 #define KVM_PTE_LEAF_ATTR_LO_S1_AP_RW   1
26 #define KVM_PTE_LEAF_ATTR_LO_S1_SH      GENMASK(9, 8)
27 #define KVM_PTE_LEAF_ATTR_LO_S1_SH_IS   3
28 #define KVM_PTE_LEAF_ATTR_LO_S1_AF      BIT(10)
29
30 #define KVM_PTE_LEAF_ATTR_LO_S2_MEMATTR GENMASK(5, 2)
31 #define KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R  BIT(6)
32 #define KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W  BIT(7)
33 #define KVM_PTE_LEAF_ATTR_LO_S2_SH      GENMASK(9, 8)
34 #define KVM_PTE_LEAF_ATTR_LO_S2_SH_IS   3
35 #define KVM_PTE_LEAF_ATTR_LO_S2_AF      BIT(10)
36
37 #define KVM_PTE_LEAF_ATTR_HI            GENMASK(63, 51)
38
39 #define KVM_PTE_LEAF_ATTR_HI_SW         GENMASK(58, 55)
40
41 #define KVM_PTE_LEAF_ATTR_HI_S1_XN      BIT(54)
42
43 #define KVM_PTE_LEAF_ATTR_HI_S2_XN      BIT(54)
44
45 #define KVM_PTE_LEAF_ATTR_S2_PERMS      (KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | \
46                                          KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | \
47                                          KVM_PTE_LEAF_ATTR_HI_S2_XN)
48
49 #define KVM_INVALID_PTE_OWNER_MASK      GENMASK(9, 2)
50 #define KVM_MAX_OWNER_ID                1
51
52 /*
53  * Used to indicate a pte for which a 'break-before-make' sequence is in
54  * progress.
55  */
56 #define KVM_INVALID_PTE_LOCKED          BIT(10)
57
58 struct kvm_pgtable_walk_data {
59         struct kvm_pgtable_walker       *walker;
60
61         u64                             addr;
62         u64                             end;
63 };
64
65 static bool kvm_phys_is_valid(u64 phys)
66 {
67         return phys < BIT(id_aa64mmfr0_parange_to_phys_shift(ID_AA64MMFR0_EL1_PARANGE_MAX));
68 }
69
70 static bool kvm_block_mapping_supported(const struct kvm_pgtable_visit_ctx *ctx, u64 phys)
71 {
72         u64 granule = kvm_granule_size(ctx->level);
73
74         if (!kvm_level_supports_block_mapping(ctx->level))
75                 return false;
76
77         if (granule > (ctx->end - ctx->addr))
78                 return false;
79
80         if (kvm_phys_is_valid(phys) && !IS_ALIGNED(phys, granule))
81                 return false;
82
83         return IS_ALIGNED(ctx->addr, granule);
84 }
85
86 static u32 kvm_pgtable_idx(struct kvm_pgtable_walk_data *data, u32 level)
87 {
88         u64 shift = kvm_granule_shift(level);
89         u64 mask = BIT(PAGE_SHIFT - 3) - 1;
90
91         return (data->addr >> shift) & mask;
92 }
93
94 static u32 kvm_pgd_page_idx(struct kvm_pgtable *pgt, u64 addr)
95 {
96         u64 shift = kvm_granule_shift(pgt->start_level - 1); /* May underflow */
97         u64 mask = BIT(pgt->ia_bits) - 1;
98
99         return (addr & mask) >> shift;
100 }
101
102 static u32 kvm_pgd_pages(u32 ia_bits, u32 start_level)
103 {
104         struct kvm_pgtable pgt = {
105                 .ia_bits        = ia_bits,
106                 .start_level    = start_level,
107         };
108
109         return kvm_pgd_page_idx(&pgt, -1ULL) + 1;
110 }
111
112 static bool kvm_pte_table(kvm_pte_t pte, u32 level)
113 {
114         if (level == KVM_PGTABLE_MAX_LEVELS - 1)
115                 return false;
116
117         if (!kvm_pte_valid(pte))
118                 return false;
119
120         return FIELD_GET(KVM_PTE_TYPE, pte) == KVM_PTE_TYPE_TABLE;
121 }
122
123 static kvm_pte_t *kvm_pte_follow(kvm_pte_t pte, struct kvm_pgtable_mm_ops *mm_ops)
124 {
125         return mm_ops->phys_to_virt(kvm_pte_to_phys(pte));
126 }
127
128 static void kvm_clear_pte(kvm_pte_t *ptep)
129 {
130         WRITE_ONCE(*ptep, 0);
131 }
132
133 static kvm_pte_t kvm_init_table_pte(kvm_pte_t *childp, struct kvm_pgtable_mm_ops *mm_ops)
134 {
135         kvm_pte_t pte = kvm_phys_to_pte(mm_ops->virt_to_phys(childp));
136
137         pte |= FIELD_PREP(KVM_PTE_TYPE, KVM_PTE_TYPE_TABLE);
138         pte |= KVM_PTE_VALID;
139         return pte;
140 }
141
142 static kvm_pte_t kvm_init_valid_leaf_pte(u64 pa, kvm_pte_t attr, u32 level)
143 {
144         kvm_pte_t pte = kvm_phys_to_pte(pa);
145         u64 type = (level == KVM_PGTABLE_MAX_LEVELS - 1) ? KVM_PTE_TYPE_PAGE :
146                                                            KVM_PTE_TYPE_BLOCK;
147
148         pte |= attr & (KVM_PTE_LEAF_ATTR_LO | KVM_PTE_LEAF_ATTR_HI);
149         pte |= FIELD_PREP(KVM_PTE_TYPE, type);
150         pte |= KVM_PTE_VALID;
151
152         return pte;
153 }
154
155 static kvm_pte_t kvm_init_invalid_leaf_owner(u8 owner_id)
156 {
157         return FIELD_PREP(KVM_INVALID_PTE_OWNER_MASK, owner_id);
158 }
159
160 static int kvm_pgtable_visitor_cb(struct kvm_pgtable_walk_data *data,
161                                   const struct kvm_pgtable_visit_ctx *ctx,
162                                   enum kvm_pgtable_walk_flags visit)
163 {
164         struct kvm_pgtable_walker *walker = data->walker;
165
166         /* Ensure the appropriate lock is held (e.g. RCU lock for stage-2 MMU) */
167         WARN_ON_ONCE(kvm_pgtable_walk_shared(ctx) && !kvm_pgtable_walk_lock_held());
168         return walker->cb(ctx, visit);
169 }
170
171 static bool kvm_pgtable_walk_continue(const struct kvm_pgtable_walker *walker,
172                                       int r)
173 {
174         /*
175          * Visitor callbacks return EAGAIN when the conditions that led to a
176          * fault are no longer reflected in the page tables due to a race to
177          * update a PTE. In the context of a fault handler this is interpreted
178          * as a signal to retry guest execution.
179          *
180          * Ignore the return code altogether for walkers outside a fault handler
181          * (e.g. write protecting a range of memory) and chug along with the
182          * page table walk.
183          */
184         if (r == -EAGAIN)
185                 return !(walker->flags & KVM_PGTABLE_WALK_HANDLE_FAULT);
186
187         return !r;
188 }
189
190 static int __kvm_pgtable_walk(struct kvm_pgtable_walk_data *data,
191                               struct kvm_pgtable_mm_ops *mm_ops, kvm_pteref_t pgtable, u32 level);
192
193 static inline int __kvm_pgtable_visit(struct kvm_pgtable_walk_data *data,
194                                       struct kvm_pgtable_mm_ops *mm_ops,
195                                       kvm_pteref_t pteref, u32 level)
196 {
197         enum kvm_pgtable_walk_flags flags = data->walker->flags;
198         kvm_pte_t *ptep = kvm_dereference_pteref(data->walker, pteref);
199         struct kvm_pgtable_visit_ctx ctx = {
200                 .ptep   = ptep,
201                 .old    = READ_ONCE(*ptep),
202                 .arg    = data->walker->arg,
203                 .mm_ops = mm_ops,
204                 .addr   = data->addr,
205                 .end    = data->end,
206                 .level  = level,
207                 .flags  = flags,
208         };
209         int ret = 0;
210         kvm_pteref_t childp;
211         bool table = kvm_pte_table(ctx.old, level);
212
213         if (table && (ctx.flags & KVM_PGTABLE_WALK_TABLE_PRE))
214                 ret = kvm_pgtable_visitor_cb(data, &ctx, KVM_PGTABLE_WALK_TABLE_PRE);
215
216         if (!table && (ctx.flags & KVM_PGTABLE_WALK_LEAF)) {
217                 ret = kvm_pgtable_visitor_cb(data, &ctx, KVM_PGTABLE_WALK_LEAF);
218                 ctx.old = READ_ONCE(*ptep);
219                 table = kvm_pte_table(ctx.old, level);
220         }
221
222         if (!kvm_pgtable_walk_continue(data->walker, ret))
223                 goto out;
224
225         if (!table) {
226                 data->addr = ALIGN_DOWN(data->addr, kvm_granule_size(level));
227                 data->addr += kvm_granule_size(level);
228                 goto out;
229         }
230
231         childp = (kvm_pteref_t)kvm_pte_follow(ctx.old, mm_ops);
232         ret = __kvm_pgtable_walk(data, mm_ops, childp, level + 1);
233         if (!kvm_pgtable_walk_continue(data->walker, ret))
234                 goto out;
235
236         if (ctx.flags & KVM_PGTABLE_WALK_TABLE_POST)
237                 ret = kvm_pgtable_visitor_cb(data, &ctx, KVM_PGTABLE_WALK_TABLE_POST);
238
239 out:
240         if (kvm_pgtable_walk_continue(data->walker, ret))
241                 return 0;
242
243         return ret;
244 }
245
246 static int __kvm_pgtable_walk(struct kvm_pgtable_walk_data *data,
247                               struct kvm_pgtable_mm_ops *mm_ops, kvm_pteref_t pgtable, u32 level)
248 {
249         u32 idx;
250         int ret = 0;
251
252         if (WARN_ON_ONCE(level >= KVM_PGTABLE_MAX_LEVELS))
253                 return -EINVAL;
254
255         for (idx = kvm_pgtable_idx(data, level); idx < PTRS_PER_PTE; ++idx) {
256                 kvm_pteref_t pteref = &pgtable[idx];
257
258                 if (data->addr >= data->end)
259                         break;
260
261                 ret = __kvm_pgtable_visit(data, mm_ops, pteref, level);
262                 if (ret)
263                         break;
264         }
265
266         return ret;
267 }
268
269 static int _kvm_pgtable_walk(struct kvm_pgtable *pgt, struct kvm_pgtable_walk_data *data)
270 {
271         u32 idx;
272         int ret = 0;
273         u64 limit = BIT(pgt->ia_bits);
274
275         if (data->addr > limit || data->end > limit)
276                 return -ERANGE;
277
278         if (!pgt->pgd)
279                 return -EINVAL;
280
281         for (idx = kvm_pgd_page_idx(pgt, data->addr); data->addr < data->end; ++idx) {
282                 kvm_pteref_t pteref = &pgt->pgd[idx * PTRS_PER_PTE];
283
284                 ret = __kvm_pgtable_walk(data, pgt->mm_ops, pteref, pgt->start_level);
285                 if (ret)
286                         break;
287         }
288
289         return ret;
290 }
291
292 int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size,
293                      struct kvm_pgtable_walker *walker)
294 {
295         struct kvm_pgtable_walk_data walk_data = {
296                 .addr   = ALIGN_DOWN(addr, PAGE_SIZE),
297                 .end    = PAGE_ALIGN(walk_data.addr + size),
298                 .walker = walker,
299         };
300         int r;
301
302         r = kvm_pgtable_walk_begin(walker);
303         if (r)
304                 return r;
305
306         r = _kvm_pgtable_walk(pgt, &walk_data);
307         kvm_pgtable_walk_end(walker);
308
309         return r;
310 }
311
312 struct leaf_walk_data {
313         kvm_pte_t       pte;
314         u32             level;
315 };
316
317 static int leaf_walker(const struct kvm_pgtable_visit_ctx *ctx,
318                        enum kvm_pgtable_walk_flags visit)
319 {
320         struct leaf_walk_data *data = ctx->arg;
321
322         data->pte   = ctx->old;
323         data->level = ctx->level;
324
325         return 0;
326 }
327
328 int kvm_pgtable_get_leaf(struct kvm_pgtable *pgt, u64 addr,
329                          kvm_pte_t *ptep, u32 *level)
330 {
331         struct leaf_walk_data data;
332         struct kvm_pgtable_walker walker = {
333                 .cb     = leaf_walker,
334                 .flags  = KVM_PGTABLE_WALK_LEAF,
335                 .arg    = &data,
336         };
337         int ret;
338
339         ret = kvm_pgtable_walk(pgt, ALIGN_DOWN(addr, PAGE_SIZE),
340                                PAGE_SIZE, &walker);
341         if (!ret) {
342                 if (ptep)
343                         *ptep  = data.pte;
344                 if (level)
345                         *level = data.level;
346         }
347
348         return ret;
349 }
350
351 struct hyp_map_data {
352         u64                             phys;
353         kvm_pte_t                       attr;
354 };
355
356 static int hyp_set_prot_attr(enum kvm_pgtable_prot prot, kvm_pte_t *ptep)
357 {
358         bool device = prot & KVM_PGTABLE_PROT_DEVICE;
359         u32 mtype = device ? MT_DEVICE_nGnRE : MT_NORMAL;
360         kvm_pte_t attr = FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_ATTRIDX, mtype);
361         u32 sh = KVM_PTE_LEAF_ATTR_LO_S1_SH_IS;
362         u32 ap = (prot & KVM_PGTABLE_PROT_W) ? KVM_PTE_LEAF_ATTR_LO_S1_AP_RW :
363                                                KVM_PTE_LEAF_ATTR_LO_S1_AP_RO;
364
365         if (!(prot & KVM_PGTABLE_PROT_R))
366                 return -EINVAL;
367
368         if (prot & KVM_PGTABLE_PROT_X) {
369                 if (prot & KVM_PGTABLE_PROT_W)
370                         return -EINVAL;
371
372                 if (device)
373                         return -EINVAL;
374         } else {
375                 attr |= KVM_PTE_LEAF_ATTR_HI_S1_XN;
376         }
377
378         attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_AP, ap);
379         attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_SH, sh);
380         attr |= KVM_PTE_LEAF_ATTR_LO_S1_AF;
381         attr |= prot & KVM_PTE_LEAF_ATTR_HI_SW;
382         *ptep = attr;
383
384         return 0;
385 }
386
387 enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte)
388 {
389         enum kvm_pgtable_prot prot = pte & KVM_PTE_LEAF_ATTR_HI_SW;
390         u32 ap;
391
392         if (!kvm_pte_valid(pte))
393                 return prot;
394
395         if (!(pte & KVM_PTE_LEAF_ATTR_HI_S1_XN))
396                 prot |= KVM_PGTABLE_PROT_X;
397
398         ap = FIELD_GET(KVM_PTE_LEAF_ATTR_LO_S1_AP, pte);
399         if (ap == KVM_PTE_LEAF_ATTR_LO_S1_AP_RO)
400                 prot |= KVM_PGTABLE_PROT_R;
401         else if (ap == KVM_PTE_LEAF_ATTR_LO_S1_AP_RW)
402                 prot |= KVM_PGTABLE_PROT_RW;
403
404         return prot;
405 }
406
407 static bool hyp_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx,
408                                     struct hyp_map_data *data)
409 {
410         kvm_pte_t new;
411         u64 granule = kvm_granule_size(ctx->level), phys = data->phys;
412
413         if (!kvm_block_mapping_supported(ctx, phys))
414                 return false;
415
416         data->phys += granule;
417         new = kvm_init_valid_leaf_pte(phys, data->attr, ctx->level);
418         if (ctx->old == new)
419                 return true;
420         if (!kvm_pte_valid(ctx->old))
421                 ctx->mm_ops->get_page(ctx->ptep);
422         else if (WARN_ON((ctx->old ^ new) & ~KVM_PTE_LEAF_ATTR_HI_SW))
423                 return false;
424
425         smp_store_release(ctx->ptep, new);
426         return true;
427 }
428
429 static int hyp_map_walker(const struct kvm_pgtable_visit_ctx *ctx,
430                           enum kvm_pgtable_walk_flags visit)
431 {
432         kvm_pte_t *childp, new;
433         struct hyp_map_data *data = ctx->arg;
434         struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
435
436         if (hyp_map_walker_try_leaf(ctx, data))
437                 return 0;
438
439         if (WARN_ON(ctx->level == KVM_PGTABLE_MAX_LEVELS - 1))
440                 return -EINVAL;
441
442         childp = (kvm_pte_t *)mm_ops->zalloc_page(NULL);
443         if (!childp)
444                 return -ENOMEM;
445
446         new = kvm_init_table_pte(childp, mm_ops);
447         mm_ops->get_page(ctx->ptep);
448         smp_store_release(ctx->ptep, new);
449
450         return 0;
451 }
452
453 int kvm_pgtable_hyp_map(struct kvm_pgtable *pgt, u64 addr, u64 size, u64 phys,
454                         enum kvm_pgtable_prot prot)
455 {
456         int ret;
457         struct hyp_map_data map_data = {
458                 .phys   = ALIGN_DOWN(phys, PAGE_SIZE),
459         };
460         struct kvm_pgtable_walker walker = {
461                 .cb     = hyp_map_walker,
462                 .flags  = KVM_PGTABLE_WALK_LEAF,
463                 .arg    = &map_data,
464         };
465
466         ret = hyp_set_prot_attr(prot, &map_data.attr);
467         if (ret)
468                 return ret;
469
470         ret = kvm_pgtable_walk(pgt, addr, size, &walker);
471         dsb(ishst);
472         isb();
473         return ret;
474 }
475
476 static int hyp_unmap_walker(const struct kvm_pgtable_visit_ctx *ctx,
477                             enum kvm_pgtable_walk_flags visit)
478 {
479         kvm_pte_t *childp = NULL;
480         u64 granule = kvm_granule_size(ctx->level);
481         u64 *unmapped = ctx->arg;
482         struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
483
484         if (!kvm_pte_valid(ctx->old))
485                 return -EINVAL;
486
487         if (kvm_pte_table(ctx->old, ctx->level)) {
488                 childp = kvm_pte_follow(ctx->old, mm_ops);
489
490                 if (mm_ops->page_count(childp) != 1)
491                         return 0;
492
493                 kvm_clear_pte(ctx->ptep);
494                 dsb(ishst);
495                 __tlbi_level(vae2is, __TLBI_VADDR(ctx->addr, 0), ctx->level);
496         } else {
497                 if (ctx->end - ctx->addr < granule)
498                         return -EINVAL;
499
500                 kvm_clear_pte(ctx->ptep);
501                 dsb(ishst);
502                 __tlbi_level(vale2is, __TLBI_VADDR(ctx->addr, 0), ctx->level);
503                 *unmapped += granule;
504         }
505
506         dsb(ish);
507         isb();
508         mm_ops->put_page(ctx->ptep);
509
510         if (childp)
511                 mm_ops->put_page(childp);
512
513         return 0;
514 }
515
516 u64 kvm_pgtable_hyp_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size)
517 {
518         u64 unmapped = 0;
519         struct kvm_pgtable_walker walker = {
520                 .cb     = hyp_unmap_walker,
521                 .arg    = &unmapped,
522                 .flags  = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST,
523         };
524
525         if (!pgt->mm_ops->page_count)
526                 return 0;
527
528         kvm_pgtable_walk(pgt, addr, size, &walker);
529         return unmapped;
530 }
531
532 int kvm_pgtable_hyp_init(struct kvm_pgtable *pgt, u32 va_bits,
533                          struct kvm_pgtable_mm_ops *mm_ops)
534 {
535         u64 levels = ARM64_HW_PGTABLE_LEVELS(va_bits);
536
537         pgt->pgd = (kvm_pteref_t)mm_ops->zalloc_page(NULL);
538         if (!pgt->pgd)
539                 return -ENOMEM;
540
541         pgt->ia_bits            = va_bits;
542         pgt->start_level        = KVM_PGTABLE_MAX_LEVELS - levels;
543         pgt->mm_ops             = mm_ops;
544         pgt->mmu                = NULL;
545         pgt->force_pte_cb       = NULL;
546
547         return 0;
548 }
549
550 static int hyp_free_walker(const struct kvm_pgtable_visit_ctx *ctx,
551                            enum kvm_pgtable_walk_flags visit)
552 {
553         struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
554
555         if (!kvm_pte_valid(ctx->old))
556                 return 0;
557
558         mm_ops->put_page(ctx->ptep);
559
560         if (kvm_pte_table(ctx->old, ctx->level))
561                 mm_ops->put_page(kvm_pte_follow(ctx->old, mm_ops));
562
563         return 0;
564 }
565
566 void kvm_pgtable_hyp_destroy(struct kvm_pgtable *pgt)
567 {
568         struct kvm_pgtable_walker walker = {
569                 .cb     = hyp_free_walker,
570                 .flags  = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST,
571         };
572
573         WARN_ON(kvm_pgtable_walk(pgt, 0, BIT(pgt->ia_bits), &walker));
574         pgt->mm_ops->put_page(kvm_dereference_pteref(&walker, pgt->pgd));
575         pgt->pgd = NULL;
576 }
577
578 struct stage2_map_data {
579         u64                             phys;
580         kvm_pte_t                       attr;
581         u8                              owner_id;
582
583         kvm_pte_t                       *anchor;
584         kvm_pte_t                       *childp;
585
586         struct kvm_s2_mmu               *mmu;
587         void                            *memcache;
588
589         /* Force mappings to page granularity */
590         bool                            force_pte;
591 };
592
593 u64 kvm_get_vtcr(u64 mmfr0, u64 mmfr1, u32 phys_shift)
594 {
595         u64 vtcr = VTCR_EL2_FLAGS;
596         u8 lvls;
597
598         vtcr |= kvm_get_parange(mmfr0) << VTCR_EL2_PS_SHIFT;
599         vtcr |= VTCR_EL2_T0SZ(phys_shift);
600         /*
601          * Use a minimum 2 level page table to prevent splitting
602          * host PMD huge pages at stage2.
603          */
604         lvls = stage2_pgtable_levels(phys_shift);
605         if (lvls < 2)
606                 lvls = 2;
607         vtcr |= VTCR_EL2_LVLS_TO_SL0(lvls);
608
609 #ifdef CONFIG_ARM64_HW_AFDBM
610         /*
611          * Enable the Hardware Access Flag management, unconditionally
612          * on all CPUs. The features is RES0 on CPUs without the support
613          * and must be ignored by the CPUs.
614          */
615         vtcr |= VTCR_EL2_HA;
616 #endif /* CONFIG_ARM64_HW_AFDBM */
617
618         /* Set the vmid bits */
619         vtcr |= (get_vmid_bits(mmfr1) == 16) ?
620                 VTCR_EL2_VS_16BIT :
621                 VTCR_EL2_VS_8BIT;
622
623         return vtcr;
624 }
625
626 static bool stage2_has_fwb(struct kvm_pgtable *pgt)
627 {
628         if (!cpus_have_const_cap(ARM64_HAS_STAGE2_FWB))
629                 return false;
630
631         return !(pgt->flags & KVM_PGTABLE_S2_NOFWB);
632 }
633
634 #define KVM_S2_MEMATTR(pgt, attr) PAGE_S2_MEMATTR(attr, stage2_has_fwb(pgt))
635
636 static int stage2_set_prot_attr(struct kvm_pgtable *pgt, enum kvm_pgtable_prot prot,
637                                 kvm_pte_t *ptep)
638 {
639         bool device = prot & KVM_PGTABLE_PROT_DEVICE;
640         kvm_pte_t attr = device ? KVM_S2_MEMATTR(pgt, DEVICE_nGnRE) :
641                             KVM_S2_MEMATTR(pgt, NORMAL);
642         u32 sh = KVM_PTE_LEAF_ATTR_LO_S2_SH_IS;
643
644         if (!(prot & KVM_PGTABLE_PROT_X))
645                 attr |= KVM_PTE_LEAF_ATTR_HI_S2_XN;
646         else if (device)
647                 return -EINVAL;
648
649         if (prot & KVM_PGTABLE_PROT_R)
650                 attr |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R;
651
652         if (prot & KVM_PGTABLE_PROT_W)
653                 attr |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W;
654
655         attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S2_SH, sh);
656         attr |= KVM_PTE_LEAF_ATTR_LO_S2_AF;
657         attr |= prot & KVM_PTE_LEAF_ATTR_HI_SW;
658         *ptep = attr;
659
660         return 0;
661 }
662
663 enum kvm_pgtable_prot kvm_pgtable_stage2_pte_prot(kvm_pte_t pte)
664 {
665         enum kvm_pgtable_prot prot = pte & KVM_PTE_LEAF_ATTR_HI_SW;
666
667         if (!kvm_pte_valid(pte))
668                 return prot;
669
670         if (pte & KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R)
671                 prot |= KVM_PGTABLE_PROT_R;
672         if (pte & KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W)
673                 prot |= KVM_PGTABLE_PROT_W;
674         if (!(pte & KVM_PTE_LEAF_ATTR_HI_S2_XN))
675                 prot |= KVM_PGTABLE_PROT_X;
676
677         return prot;
678 }
679
680 static bool stage2_pte_needs_update(kvm_pte_t old, kvm_pte_t new)
681 {
682         if (!kvm_pte_valid(old) || !kvm_pte_valid(new))
683                 return true;
684
685         return ((old ^ new) & (~KVM_PTE_LEAF_ATTR_S2_PERMS));
686 }
687
688 static bool stage2_pte_is_counted(kvm_pte_t pte)
689 {
690         /*
691          * The refcount tracks valid entries as well as invalid entries if they
692          * encode ownership of a page to another entity than the page-table
693          * owner, whose id is 0.
694          */
695         return !!pte;
696 }
697
698 static bool stage2_pte_is_locked(kvm_pte_t pte)
699 {
700         return !kvm_pte_valid(pte) && (pte & KVM_INVALID_PTE_LOCKED);
701 }
702
703 static bool stage2_try_set_pte(const struct kvm_pgtable_visit_ctx *ctx, kvm_pte_t new)
704 {
705         if (!kvm_pgtable_walk_shared(ctx)) {
706                 WRITE_ONCE(*ctx->ptep, new);
707                 return true;
708         }
709
710         return cmpxchg(ctx->ptep, ctx->old, new) == ctx->old;
711 }
712
713 /**
714  * stage2_try_break_pte() - Invalidates a pte according to the
715  *                          'break-before-make' requirements of the
716  *                          architecture.
717  *
718  * @ctx: context of the visited pte.
719  * @mmu: stage-2 mmu
720  *
721  * Returns: true if the pte was successfully broken.
722  *
723  * If the removed pte was valid, performs the necessary serialization and TLB
724  * invalidation for the old value. For counted ptes, drops the reference count
725  * on the containing table page.
726  */
727 static bool stage2_try_break_pte(const struct kvm_pgtable_visit_ctx *ctx,
728                                  struct kvm_s2_mmu *mmu)
729 {
730         struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
731
732         if (stage2_pte_is_locked(ctx->old)) {
733                 /*
734                  * Should never occur if this walker has exclusive access to the
735                  * page tables.
736                  */
737                 WARN_ON(!kvm_pgtable_walk_shared(ctx));
738                 return false;
739         }
740
741         if (!stage2_try_set_pte(ctx, KVM_INVALID_PTE_LOCKED))
742                 return false;
743
744         /*
745          * Perform the appropriate TLB invalidation based on the evicted pte
746          * value (if any).
747          */
748         if (kvm_pte_table(ctx->old, ctx->level))
749                 kvm_call_hyp(__kvm_tlb_flush_vmid, mmu);
750         else if (kvm_pte_valid(ctx->old))
751                 kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu, ctx->addr, ctx->level);
752
753         if (stage2_pte_is_counted(ctx->old))
754                 mm_ops->put_page(ctx->ptep);
755
756         return true;
757 }
758
759 static void stage2_make_pte(const struct kvm_pgtable_visit_ctx *ctx, kvm_pte_t new)
760 {
761         struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
762
763         WARN_ON(!stage2_pte_is_locked(*ctx->ptep));
764
765         if (stage2_pte_is_counted(new))
766                 mm_ops->get_page(ctx->ptep);
767
768         smp_store_release(ctx->ptep, new);
769 }
770
771 static void stage2_put_pte(const struct kvm_pgtable_visit_ctx *ctx, struct kvm_s2_mmu *mmu,
772                            struct kvm_pgtable_mm_ops *mm_ops)
773 {
774         /*
775          * Clear the existing PTE, and perform break-before-make with
776          * TLB maintenance if it was valid.
777          */
778         if (kvm_pte_valid(ctx->old)) {
779                 kvm_clear_pte(ctx->ptep);
780                 kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu, ctx->addr, ctx->level);
781         }
782
783         mm_ops->put_page(ctx->ptep);
784 }
785
786 static bool stage2_pte_cacheable(struct kvm_pgtable *pgt, kvm_pte_t pte)
787 {
788         u64 memattr = pte & KVM_PTE_LEAF_ATTR_LO_S2_MEMATTR;
789         return memattr == KVM_S2_MEMATTR(pgt, NORMAL);
790 }
791
792 static bool stage2_pte_executable(kvm_pte_t pte)
793 {
794         return !(pte & KVM_PTE_LEAF_ATTR_HI_S2_XN);
795 }
796
797 static bool stage2_leaf_mapping_allowed(const struct kvm_pgtable_visit_ctx *ctx,
798                                         struct stage2_map_data *data)
799 {
800         if (data->force_pte && (ctx->level < (KVM_PGTABLE_MAX_LEVELS - 1)))
801                 return false;
802
803         return kvm_block_mapping_supported(ctx, data->phys);
804 }
805
806 static int stage2_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx,
807                                       struct stage2_map_data *data)
808 {
809         kvm_pte_t new;
810         u64 granule = kvm_granule_size(ctx->level), phys = data->phys;
811         struct kvm_pgtable *pgt = data->mmu->pgt;
812         struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
813
814         if (!stage2_leaf_mapping_allowed(ctx, data))
815                 return -E2BIG;
816
817         if (kvm_phys_is_valid(phys))
818                 new = kvm_init_valid_leaf_pte(phys, data->attr, ctx->level);
819         else
820                 new = kvm_init_invalid_leaf_owner(data->owner_id);
821
822         /*
823          * Skip updating the PTE if we are trying to recreate the exact
824          * same mapping or only change the access permissions. Instead,
825          * the vCPU will exit one more time from guest if still needed
826          * and then go through the path of relaxing permissions.
827          */
828         if (!stage2_pte_needs_update(ctx->old, new))
829                 return -EAGAIN;
830
831         if (!stage2_try_break_pte(ctx, data->mmu))
832                 return -EAGAIN;
833
834         /* Perform CMOs before installation of the guest stage-2 PTE */
835         if (mm_ops->dcache_clean_inval_poc && stage2_pte_cacheable(pgt, new))
836                 mm_ops->dcache_clean_inval_poc(kvm_pte_follow(new, mm_ops),
837                                                 granule);
838
839         if (mm_ops->icache_inval_pou && stage2_pte_executable(new))
840                 mm_ops->icache_inval_pou(kvm_pte_follow(new, mm_ops), granule);
841
842         stage2_make_pte(ctx, new);
843
844         if (kvm_phys_is_valid(phys))
845                 data->phys += granule;
846         return 0;
847 }
848
849 static int stage2_map_walk_table_pre(const struct kvm_pgtable_visit_ctx *ctx,
850                                      struct stage2_map_data *data)
851 {
852         struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
853         kvm_pte_t *childp = kvm_pte_follow(ctx->old, mm_ops);
854         int ret;
855
856         if (!stage2_leaf_mapping_allowed(ctx, data))
857                 return 0;
858
859         ret = stage2_map_walker_try_leaf(ctx, data);
860         if (ret)
861                 return ret;
862
863         mm_ops->free_removed_table(childp, ctx->level);
864         return 0;
865 }
866
867 static int stage2_map_walk_leaf(const struct kvm_pgtable_visit_ctx *ctx,
868                                 struct stage2_map_data *data)
869 {
870         struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
871         kvm_pte_t *childp, new;
872         int ret;
873
874         ret = stage2_map_walker_try_leaf(ctx, data);
875         if (ret != -E2BIG)
876                 return ret;
877
878         if (WARN_ON(ctx->level == KVM_PGTABLE_MAX_LEVELS - 1))
879                 return -EINVAL;
880
881         if (!data->memcache)
882                 return -ENOMEM;
883
884         childp = mm_ops->zalloc_page(data->memcache);
885         if (!childp)
886                 return -ENOMEM;
887
888         if (!stage2_try_break_pte(ctx, data->mmu)) {
889                 mm_ops->put_page(childp);
890                 return -EAGAIN;
891         }
892
893         /*
894          * If we've run into an existing block mapping then replace it with
895          * a table. Accesses beyond 'end' that fall within the new table
896          * will be mapped lazily.
897          */
898         new = kvm_init_table_pte(childp, mm_ops);
899         stage2_make_pte(ctx, new);
900
901         return 0;
902 }
903
904 /*
905  * The TABLE_PRE callback runs for table entries on the way down, looking
906  * for table entries which we could conceivably replace with a block entry
907  * for this mapping. If it finds one it replaces the entry and calls
908  * kvm_pgtable_mm_ops::free_removed_table() to tear down the detached table.
909  *
910  * Otherwise, the LEAF callback performs the mapping at the existing leaves
911  * instead.
912  */
913 static int stage2_map_walker(const struct kvm_pgtable_visit_ctx *ctx,
914                              enum kvm_pgtable_walk_flags visit)
915 {
916         struct stage2_map_data *data = ctx->arg;
917
918         switch (visit) {
919         case KVM_PGTABLE_WALK_TABLE_PRE:
920                 return stage2_map_walk_table_pre(ctx, data);
921         case KVM_PGTABLE_WALK_LEAF:
922                 return stage2_map_walk_leaf(ctx, data);
923         default:
924                 return -EINVAL;
925         }
926 }
927
928 int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
929                            u64 phys, enum kvm_pgtable_prot prot,
930                            void *mc, enum kvm_pgtable_walk_flags flags)
931 {
932         int ret;
933         struct stage2_map_data map_data = {
934                 .phys           = ALIGN_DOWN(phys, PAGE_SIZE),
935                 .mmu            = pgt->mmu,
936                 .memcache       = mc,
937                 .force_pte      = pgt->force_pte_cb && pgt->force_pte_cb(addr, addr + size, prot),
938         };
939         struct kvm_pgtable_walker walker = {
940                 .cb             = stage2_map_walker,
941                 .flags          = flags |
942                                   KVM_PGTABLE_WALK_TABLE_PRE |
943                                   KVM_PGTABLE_WALK_LEAF,
944                 .arg            = &map_data,
945         };
946
947         if (WARN_ON((pgt->flags & KVM_PGTABLE_S2_IDMAP) && (addr != phys)))
948                 return -EINVAL;
949
950         ret = stage2_set_prot_attr(pgt, prot, &map_data.attr);
951         if (ret)
952                 return ret;
953
954         ret = kvm_pgtable_walk(pgt, addr, size, &walker);
955         dsb(ishst);
956         return ret;
957 }
958
959 int kvm_pgtable_stage2_set_owner(struct kvm_pgtable *pgt, u64 addr, u64 size,
960                                  void *mc, u8 owner_id)
961 {
962         int ret;
963         struct stage2_map_data map_data = {
964                 .phys           = KVM_PHYS_INVALID,
965                 .mmu            = pgt->mmu,
966                 .memcache       = mc,
967                 .owner_id       = owner_id,
968                 .force_pte      = true,
969         };
970         struct kvm_pgtable_walker walker = {
971                 .cb             = stage2_map_walker,
972                 .flags          = KVM_PGTABLE_WALK_TABLE_PRE |
973                                   KVM_PGTABLE_WALK_LEAF,
974                 .arg            = &map_data,
975         };
976
977         if (owner_id > KVM_MAX_OWNER_ID)
978                 return -EINVAL;
979
980         ret = kvm_pgtable_walk(pgt, addr, size, &walker);
981         return ret;
982 }
983
984 static int stage2_unmap_walker(const struct kvm_pgtable_visit_ctx *ctx,
985                                enum kvm_pgtable_walk_flags visit)
986 {
987         struct kvm_pgtable *pgt = ctx->arg;
988         struct kvm_s2_mmu *mmu = pgt->mmu;
989         struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
990         kvm_pte_t *childp = NULL;
991         bool need_flush = false;
992
993         if (!kvm_pte_valid(ctx->old)) {
994                 if (stage2_pte_is_counted(ctx->old)) {
995                         kvm_clear_pte(ctx->ptep);
996                         mm_ops->put_page(ctx->ptep);
997                 }
998                 return 0;
999         }
1000
1001         if (kvm_pte_table(ctx->old, ctx->level)) {
1002                 childp = kvm_pte_follow(ctx->old, mm_ops);
1003
1004                 if (mm_ops->page_count(childp) != 1)
1005                         return 0;
1006         } else if (stage2_pte_cacheable(pgt, ctx->old)) {
1007                 need_flush = !stage2_has_fwb(pgt);
1008         }
1009
1010         /*
1011          * This is similar to the map() path in that we unmap the entire
1012          * block entry and rely on the remaining portions being faulted
1013          * back lazily.
1014          */
1015         stage2_put_pte(ctx, mmu, mm_ops);
1016
1017         if (need_flush && mm_ops->dcache_clean_inval_poc)
1018                 mm_ops->dcache_clean_inval_poc(kvm_pte_follow(ctx->old, mm_ops),
1019                                                kvm_granule_size(ctx->level));
1020
1021         if (childp)
1022                 mm_ops->put_page(childp);
1023
1024         return 0;
1025 }
1026
1027 int kvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size)
1028 {
1029         struct kvm_pgtable_walker walker = {
1030                 .cb     = stage2_unmap_walker,
1031                 .arg    = pgt,
1032                 .flags  = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST,
1033         };
1034
1035         return kvm_pgtable_walk(pgt, addr, size, &walker);
1036 }
1037
1038 struct stage2_attr_data {
1039         kvm_pte_t                       attr_set;
1040         kvm_pte_t                       attr_clr;
1041         kvm_pte_t                       pte;
1042         u32                             level;
1043 };
1044
1045 static int stage2_attr_walker(const struct kvm_pgtable_visit_ctx *ctx,
1046                               enum kvm_pgtable_walk_flags visit)
1047 {
1048         kvm_pte_t pte = ctx->old;
1049         struct stage2_attr_data *data = ctx->arg;
1050         struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
1051
1052         if (!kvm_pte_valid(ctx->old))
1053                 return -EAGAIN;
1054
1055         data->level = ctx->level;
1056         data->pte = pte;
1057         pte &= ~data->attr_clr;
1058         pte |= data->attr_set;
1059
1060         /*
1061          * We may race with the CPU trying to set the access flag here,
1062          * but worst-case the access flag update gets lost and will be
1063          * set on the next access instead.
1064          */
1065         if (data->pte != pte) {
1066                 /*
1067                  * Invalidate instruction cache before updating the guest
1068                  * stage-2 PTE if we are going to add executable permission.
1069                  */
1070                 if (mm_ops->icache_inval_pou &&
1071                     stage2_pte_executable(pte) && !stage2_pte_executable(ctx->old))
1072                         mm_ops->icache_inval_pou(kvm_pte_follow(pte, mm_ops),
1073                                                   kvm_granule_size(ctx->level));
1074
1075                 if (!stage2_try_set_pte(ctx, pte))
1076                         return -EAGAIN;
1077         }
1078
1079         return 0;
1080 }
1081
1082 static int stage2_update_leaf_attrs(struct kvm_pgtable *pgt, u64 addr,
1083                                     u64 size, kvm_pte_t attr_set,
1084                                     kvm_pte_t attr_clr, kvm_pte_t *orig_pte,
1085                                     u32 *level, enum kvm_pgtable_walk_flags flags)
1086 {
1087         int ret;
1088         kvm_pte_t attr_mask = KVM_PTE_LEAF_ATTR_LO | KVM_PTE_LEAF_ATTR_HI;
1089         struct stage2_attr_data data = {
1090                 .attr_set       = attr_set & attr_mask,
1091                 .attr_clr       = attr_clr & attr_mask,
1092         };
1093         struct kvm_pgtable_walker walker = {
1094                 .cb             = stage2_attr_walker,
1095                 .arg            = &data,
1096                 .flags          = flags | KVM_PGTABLE_WALK_LEAF,
1097         };
1098
1099         ret = kvm_pgtable_walk(pgt, addr, size, &walker);
1100         if (ret)
1101                 return ret;
1102
1103         if (orig_pte)
1104                 *orig_pte = data.pte;
1105
1106         if (level)
1107                 *level = data.level;
1108         return 0;
1109 }
1110
1111 int kvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size)
1112 {
1113         return stage2_update_leaf_attrs(pgt, addr, size, 0,
1114                                         KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W,
1115                                         NULL, NULL, 0);
1116 }
1117
1118 kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr)
1119 {
1120         kvm_pte_t pte = 0;
1121         int ret;
1122
1123         ret = stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0,
1124                                        &pte, NULL,
1125                                        KVM_PGTABLE_WALK_HANDLE_FAULT |
1126                                        KVM_PGTABLE_WALK_SHARED);
1127         if (!ret)
1128                 dsb(ishst);
1129
1130         return pte;
1131 }
1132
1133 kvm_pte_t kvm_pgtable_stage2_mkold(struct kvm_pgtable *pgt, u64 addr)
1134 {
1135         kvm_pte_t pte = 0;
1136         stage2_update_leaf_attrs(pgt, addr, 1, 0, KVM_PTE_LEAF_ATTR_LO_S2_AF,
1137                                  &pte, NULL, 0);
1138         /*
1139          * "But where's the TLBI?!", you scream.
1140          * "Over in the core code", I sigh.
1141          *
1142          * See the '->clear_flush_young()' callback on the KVM mmu notifier.
1143          */
1144         return pte;
1145 }
1146
1147 bool kvm_pgtable_stage2_is_young(struct kvm_pgtable *pgt, u64 addr)
1148 {
1149         kvm_pte_t pte = 0;
1150         stage2_update_leaf_attrs(pgt, addr, 1, 0, 0, &pte, NULL, 0);
1151         return pte & KVM_PTE_LEAF_ATTR_LO_S2_AF;
1152 }
1153
1154 int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr,
1155                                    enum kvm_pgtable_prot prot)
1156 {
1157         int ret;
1158         u32 level;
1159         kvm_pte_t set = 0, clr = 0;
1160
1161         if (prot & KVM_PTE_LEAF_ATTR_HI_SW)
1162                 return -EINVAL;
1163
1164         if (prot & KVM_PGTABLE_PROT_R)
1165                 set |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R;
1166
1167         if (prot & KVM_PGTABLE_PROT_W)
1168                 set |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W;
1169
1170         if (prot & KVM_PGTABLE_PROT_X)
1171                 clr |= KVM_PTE_LEAF_ATTR_HI_S2_XN;
1172
1173         ret = stage2_update_leaf_attrs(pgt, addr, 1, set, clr, NULL, &level,
1174                                        KVM_PGTABLE_WALK_HANDLE_FAULT |
1175                                        KVM_PGTABLE_WALK_SHARED);
1176         if (!ret)
1177                 kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, pgt->mmu, addr, level);
1178         return ret;
1179 }
1180
1181 static int stage2_flush_walker(const struct kvm_pgtable_visit_ctx *ctx,
1182                                enum kvm_pgtable_walk_flags visit)
1183 {
1184         struct kvm_pgtable *pgt = ctx->arg;
1185         struct kvm_pgtable_mm_ops *mm_ops = pgt->mm_ops;
1186
1187         if (!kvm_pte_valid(ctx->old) || !stage2_pte_cacheable(pgt, ctx->old))
1188                 return 0;
1189
1190         if (mm_ops->dcache_clean_inval_poc)
1191                 mm_ops->dcache_clean_inval_poc(kvm_pte_follow(ctx->old, mm_ops),
1192                                                kvm_granule_size(ctx->level));
1193         return 0;
1194 }
1195
1196 int kvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size)
1197 {
1198         struct kvm_pgtable_walker walker = {
1199                 .cb     = stage2_flush_walker,
1200                 .flags  = KVM_PGTABLE_WALK_LEAF,
1201                 .arg    = pgt,
1202         };
1203
1204         if (stage2_has_fwb(pgt))
1205                 return 0;
1206
1207         return kvm_pgtable_walk(pgt, addr, size, &walker);
1208 }
1209
1210
1211 int __kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu,
1212                               struct kvm_pgtable_mm_ops *mm_ops,
1213                               enum kvm_pgtable_stage2_flags flags,
1214                               kvm_pgtable_force_pte_cb_t force_pte_cb)
1215 {
1216         size_t pgd_sz;
1217         u64 vtcr = mmu->arch->vtcr;
1218         u32 ia_bits = VTCR_EL2_IPA(vtcr);
1219         u32 sl0 = FIELD_GET(VTCR_EL2_SL0_MASK, vtcr);
1220         u32 start_level = VTCR_EL2_TGRAN_SL0_BASE - sl0;
1221
1222         pgd_sz = kvm_pgd_pages(ia_bits, start_level) * PAGE_SIZE;
1223         pgt->pgd = (kvm_pteref_t)mm_ops->zalloc_pages_exact(pgd_sz);
1224         if (!pgt->pgd)
1225                 return -ENOMEM;
1226
1227         pgt->ia_bits            = ia_bits;
1228         pgt->start_level        = start_level;
1229         pgt->mm_ops             = mm_ops;
1230         pgt->mmu                = mmu;
1231         pgt->flags              = flags;
1232         pgt->force_pte_cb       = force_pte_cb;
1233
1234         /* Ensure zeroed PGD pages are visible to the hardware walker */
1235         dsb(ishst);
1236         return 0;
1237 }
1238
1239 size_t kvm_pgtable_stage2_pgd_size(u64 vtcr)
1240 {
1241         u32 ia_bits = VTCR_EL2_IPA(vtcr);
1242         u32 sl0 = FIELD_GET(VTCR_EL2_SL0_MASK, vtcr);
1243         u32 start_level = VTCR_EL2_TGRAN_SL0_BASE - sl0;
1244
1245         return kvm_pgd_pages(ia_bits, start_level) * PAGE_SIZE;
1246 }
1247
1248 static int stage2_free_walker(const struct kvm_pgtable_visit_ctx *ctx,
1249                               enum kvm_pgtable_walk_flags visit)
1250 {
1251         struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
1252
1253         if (!stage2_pte_is_counted(ctx->old))
1254                 return 0;
1255
1256         mm_ops->put_page(ctx->ptep);
1257
1258         if (kvm_pte_table(ctx->old, ctx->level))
1259                 mm_ops->put_page(kvm_pte_follow(ctx->old, mm_ops));
1260
1261         return 0;
1262 }
1263
1264 void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt)
1265 {
1266         size_t pgd_sz;
1267         struct kvm_pgtable_walker walker = {
1268                 .cb     = stage2_free_walker,
1269                 .flags  = KVM_PGTABLE_WALK_LEAF |
1270                           KVM_PGTABLE_WALK_TABLE_POST,
1271         };
1272
1273         WARN_ON(kvm_pgtable_walk(pgt, 0, BIT(pgt->ia_bits), &walker));
1274         pgd_sz = kvm_pgd_pages(pgt->ia_bits, pgt->start_level) * PAGE_SIZE;
1275         pgt->mm_ops->free_pages_exact(kvm_dereference_pteref(&walker, pgt->pgd), pgd_sz);
1276         pgt->pgd = NULL;
1277 }
1278
1279 void kvm_pgtable_stage2_free_removed(struct kvm_pgtable_mm_ops *mm_ops, void *pgtable, u32 level)
1280 {
1281         kvm_pteref_t ptep = (kvm_pteref_t)pgtable;
1282         struct kvm_pgtable_walker walker = {
1283                 .cb     = stage2_free_walker,
1284                 .flags  = KVM_PGTABLE_WALK_LEAF |
1285                           KVM_PGTABLE_WALK_TABLE_POST,
1286         };
1287         struct kvm_pgtable_walk_data data = {
1288                 .walker = &walker,
1289
1290                 /*
1291                  * At this point the IPA really doesn't matter, as the page
1292                  * table being traversed has already been removed from the stage
1293                  * 2. Set an appropriate range to cover the entire page table.
1294                  */
1295                 .addr   = 0,
1296                 .end    = kvm_granule_size(level),
1297         };
1298
1299         WARN_ON(__kvm_pgtable_walk(&data, mm_ops, ptep, level + 1));
1300 }
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