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
kvm_pgtable_walk_skip_bbm_tlbi(const struct kvm_pgtable_visit_ctx * ctx)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
kvm_pgtable_walk_skip_cmo(const struct kvm_pgtable_visit_ctx * ctx)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
kvm_phys_is_valid(u64 phys)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
kvm_block_mapping_supported(const struct kvm_pgtable_visit_ctx * ctx,u64 phys)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
kvm_pgtable_idx(struct kvm_pgtable_walk_data * data,s8 level)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
kvm_pgd_page_idx(struct kvm_pgtable * pgt,u64 addr)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
kvm_pgd_pages(u32 ia_bits,s8 start_level)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
kvm_pte_table(kvm_pte_t pte,s8 level)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
kvm_pte_follow(kvm_pte_t pte,struct kvm_pgtable_mm_ops * mm_ops)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
kvm_clear_pte(kvm_pte_t * ptep)146 static void kvm_clear_pte(kvm_pte_t *ptep)
147 {
148 WRITE_ONCE(*ptep, 0);
149 }
150
kvm_init_table_pte(kvm_pte_t * childp,struct kvm_pgtable_mm_ops * mm_ops)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
kvm_init_valid_leaf_pte(u64 pa,kvm_pte_t attr,s8 level)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
kvm_init_invalid_leaf_owner(u8 owner_id)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
kvm_pgtable_visitor_cb(struct kvm_pgtable_walk_data * data,const struct kvm_pgtable_visit_ctx * ctx,enum kvm_pgtable_walk_flags visit)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
kvm_pgtable_walk_continue(const struct kvm_pgtable_walker * walker,int r)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
__kvm_pgtable_visit(struct kvm_pgtable_walk_data * data,struct kvm_pgtable_mm_ops * mm_ops,kvm_pteref_t pteref,s8 level)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
__kvm_pgtable_walk(struct kvm_pgtable_walk_data * data,struct kvm_pgtable_mm_ops * mm_ops,kvm_pteref_t pgtable,s8 level)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
_kvm_pgtable_walk(struct kvm_pgtable * pgt,struct kvm_pgtable_walk_data * data)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
kvm_pgtable_walk(struct kvm_pgtable * pgt,u64 addr,u64 size,struct kvm_pgtable_walker * walker)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
leaf_walker(const struct kvm_pgtable_visit_ctx * ctx,enum kvm_pgtable_walk_flags visit)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
kvm_pgtable_get_leaf(struct kvm_pgtable * pgt,u64 addr,kvm_pte_t * ptep,s8 * level)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
hyp_set_prot_attr(enum kvm_pgtable_prot prot,kvm_pte_t * ptep)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
kvm_pgtable_hyp_pte_prot(kvm_pte_t pte)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
hyp_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx * ctx,struct hyp_map_data * data)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
hyp_map_walker(const struct kvm_pgtable_visit_ctx * ctx,enum kvm_pgtable_walk_flags visit)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
kvm_pgtable_hyp_map(struct kvm_pgtable * pgt,u64 addr,u64 size,u64 phys,enum kvm_pgtable_prot prot)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
hyp_unmap_walker(const struct kvm_pgtable_visit_ctx * ctx,enum kvm_pgtable_walk_flags visit)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), ctx->level);
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
kvm_pgtable_hyp_unmap(struct kvm_pgtable * pgt,u64 addr,u64 size)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
kvm_pgtable_hyp_init(struct kvm_pgtable * pgt,u32 va_bits,struct kvm_pgtable_mm_ops * mm_ops)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
hyp_free_walker(const struct kvm_pgtable_visit_ctx * ctx,enum kvm_pgtable_walk_flags visit)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
kvm_pgtable_hyp_destroy(struct kvm_pgtable * pgt)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
kvm_get_vtcr(u64 mmfr0,u64 mmfr1,u32 phys_shift)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
stage2_has_fwb(struct kvm_pgtable * pgt)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
kvm_tlb_flush_vmid_range(struct kvm_s2_mmu * mmu,phys_addr_t addr,size_t size)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
stage2_set_prot_attr(struct kvm_pgtable * pgt,enum kvm_pgtable_prot prot,kvm_pte_t * ptep)717 static int stage2_set_prot_attr(struct kvm_pgtable *pgt, enum kvm_pgtable_prot prot,
718 kvm_pte_t *ptep)
719 {
720 bool device = prot & KVM_PGTABLE_PROT_DEVICE;
721 kvm_pte_t attr = device ? KVM_S2_MEMATTR(pgt, DEVICE_nGnRE) :
722 KVM_S2_MEMATTR(pgt, NORMAL);
723 u32 sh = KVM_PTE_LEAF_ATTR_LO_S2_SH_IS;
724
725 if (!(prot & KVM_PGTABLE_PROT_X))
726 attr |= KVM_PTE_LEAF_ATTR_HI_S2_XN;
727 else if (device)
728 return -EINVAL;
729
730 if (prot & KVM_PGTABLE_PROT_R)
731 attr |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R;
732
733 if (prot & KVM_PGTABLE_PROT_W)
734 attr |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W;
735
736 if (!kvm_lpa2_is_enabled())
737 attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S2_SH, sh);
738
739 attr |= KVM_PTE_LEAF_ATTR_LO_S2_AF;
740 attr |= prot & KVM_PTE_LEAF_ATTR_HI_SW;
741 *ptep = attr;
742
743 return 0;
744 }
745
kvm_pgtable_stage2_pte_prot(kvm_pte_t pte)746 enum kvm_pgtable_prot kvm_pgtable_stage2_pte_prot(kvm_pte_t pte)
747 {
748 enum kvm_pgtable_prot prot = pte & KVM_PTE_LEAF_ATTR_HI_SW;
749
750 if (!kvm_pte_valid(pte))
751 return prot;
752
753 if (pte & KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R)
754 prot |= KVM_PGTABLE_PROT_R;
755 if (pte & KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W)
756 prot |= KVM_PGTABLE_PROT_W;
757 if (!(pte & KVM_PTE_LEAF_ATTR_HI_S2_XN))
758 prot |= KVM_PGTABLE_PROT_X;
759
760 return prot;
761 }
762
stage2_pte_needs_update(kvm_pte_t old,kvm_pte_t new)763 static bool stage2_pte_needs_update(kvm_pte_t old, kvm_pte_t new)
764 {
765 if (!kvm_pte_valid(old) || !kvm_pte_valid(new))
766 return true;
767
768 return ((old ^ new) & (~KVM_PTE_LEAF_ATTR_S2_PERMS));
769 }
770
stage2_pte_is_counted(kvm_pte_t pte)771 static bool stage2_pte_is_counted(kvm_pte_t pte)
772 {
773 /*
774 * The refcount tracks valid entries as well as invalid entries if they
775 * encode ownership of a page to another entity than the page-table
776 * owner, whose id is 0.
777 */
778 return !!pte;
779 }
780
stage2_pte_is_locked(kvm_pte_t pte)781 static bool stage2_pte_is_locked(kvm_pte_t pte)
782 {
783 return !kvm_pte_valid(pte) && (pte & KVM_INVALID_PTE_LOCKED);
784 }
785
stage2_try_set_pte(const struct kvm_pgtable_visit_ctx * ctx,kvm_pte_t new)786 static bool stage2_try_set_pte(const struct kvm_pgtable_visit_ctx *ctx, kvm_pte_t new)
787 {
788 if (!kvm_pgtable_walk_shared(ctx)) {
789 WRITE_ONCE(*ctx->ptep, new);
790 return true;
791 }
792
793 return cmpxchg(ctx->ptep, ctx->old, new) == ctx->old;
794 }
795
796 /**
797 * stage2_try_break_pte() - Invalidates a pte according to the
798 * 'break-before-make' requirements of the
799 * architecture.
800 *
801 * @ctx: context of the visited pte.
802 * @mmu: stage-2 mmu
803 *
804 * Returns: true if the pte was successfully broken.
805 *
806 * If the removed pte was valid, performs the necessary serialization and TLB
807 * invalidation for the old value. For counted ptes, drops the reference count
808 * on the containing table page.
809 */
stage2_try_break_pte(const struct kvm_pgtable_visit_ctx * ctx,struct kvm_s2_mmu * mmu)810 static bool stage2_try_break_pte(const struct kvm_pgtable_visit_ctx *ctx,
811 struct kvm_s2_mmu *mmu)
812 {
813 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
814
815 if (stage2_pte_is_locked(ctx->old)) {
816 /*
817 * Should never occur if this walker has exclusive access to the
818 * page tables.
819 */
820 WARN_ON(!kvm_pgtable_walk_shared(ctx));
821 return false;
822 }
823
824 if (!stage2_try_set_pte(ctx, KVM_INVALID_PTE_LOCKED))
825 return false;
826
827 if (!kvm_pgtable_walk_skip_bbm_tlbi(ctx)) {
828 /*
829 * Perform the appropriate TLB invalidation based on the
830 * evicted pte value (if any).
831 */
832 if (kvm_pte_table(ctx->old, ctx->level))
833 kvm_tlb_flush_vmid_range(mmu, ctx->addr,
834 kvm_granule_size(ctx->level));
835 else if (kvm_pte_valid(ctx->old))
836 kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu,
837 ctx->addr, ctx->level);
838 }
839
840 if (stage2_pte_is_counted(ctx->old))
841 mm_ops->put_page(ctx->ptep);
842
843 return true;
844 }
845
stage2_make_pte(const struct kvm_pgtable_visit_ctx * ctx,kvm_pte_t new)846 static void stage2_make_pte(const struct kvm_pgtable_visit_ctx *ctx, kvm_pte_t new)
847 {
848 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
849
850 WARN_ON(!stage2_pte_is_locked(*ctx->ptep));
851
852 if (stage2_pte_is_counted(new))
853 mm_ops->get_page(ctx->ptep);
854
855 smp_store_release(ctx->ptep, new);
856 }
857
stage2_unmap_defer_tlb_flush(struct kvm_pgtable * pgt)858 static bool stage2_unmap_defer_tlb_flush(struct kvm_pgtable *pgt)
859 {
860 /*
861 * If FEAT_TLBIRANGE is implemented, defer the individual
862 * TLB invalidations until the entire walk is finished, and
863 * then use the range-based TLBI instructions to do the
864 * invalidations. Condition deferred TLB invalidation on the
865 * system supporting FWB as the optimization is entirely
866 * pointless when the unmap walker needs to perform CMOs.
867 */
868 return system_supports_tlb_range() && stage2_has_fwb(pgt);
869 }
870
stage2_unmap_put_pte(const struct kvm_pgtable_visit_ctx * ctx,struct kvm_s2_mmu * mmu,struct kvm_pgtable_mm_ops * mm_ops)871 static void stage2_unmap_put_pte(const struct kvm_pgtable_visit_ctx *ctx,
872 struct kvm_s2_mmu *mmu,
873 struct kvm_pgtable_mm_ops *mm_ops)
874 {
875 struct kvm_pgtable *pgt = ctx->arg;
876
877 /*
878 * Clear the existing PTE, and perform break-before-make if it was
879 * valid. Depending on the system support, defer the TLB maintenance
880 * for the same until the entire unmap walk is completed.
881 */
882 if (kvm_pte_valid(ctx->old)) {
883 kvm_clear_pte(ctx->ptep);
884
885 if (!stage2_unmap_defer_tlb_flush(pgt))
886 kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu,
887 ctx->addr, ctx->level);
888 }
889
890 mm_ops->put_page(ctx->ptep);
891 }
892
stage2_pte_cacheable(struct kvm_pgtable * pgt,kvm_pte_t pte)893 static bool stage2_pte_cacheable(struct kvm_pgtable *pgt, kvm_pte_t pte)
894 {
895 u64 memattr = pte & KVM_PTE_LEAF_ATTR_LO_S2_MEMATTR;
896 return memattr == KVM_S2_MEMATTR(pgt, NORMAL);
897 }
898
stage2_pte_executable(kvm_pte_t pte)899 static bool stage2_pte_executable(kvm_pte_t pte)
900 {
901 return !(pte & KVM_PTE_LEAF_ATTR_HI_S2_XN);
902 }
903
stage2_map_walker_phys_addr(const struct kvm_pgtable_visit_ctx * ctx,const struct stage2_map_data * data)904 static u64 stage2_map_walker_phys_addr(const struct kvm_pgtable_visit_ctx *ctx,
905 const struct stage2_map_data *data)
906 {
907 u64 phys = data->phys;
908
909 /*
910 * Stage-2 walks to update ownership data are communicated to the map
911 * walker using an invalid PA. Avoid offsetting an already invalid PA,
912 * which could overflow and make the address valid again.
913 */
914 if (!kvm_phys_is_valid(phys))
915 return phys;
916
917 /*
918 * Otherwise, work out the correct PA based on how far the walk has
919 * gotten.
920 */
921 return phys + (ctx->addr - ctx->start);
922 }
923
stage2_leaf_mapping_allowed(const struct kvm_pgtable_visit_ctx * ctx,struct stage2_map_data * data)924 static bool stage2_leaf_mapping_allowed(const struct kvm_pgtable_visit_ctx *ctx,
925 struct stage2_map_data *data)
926 {
927 u64 phys = stage2_map_walker_phys_addr(ctx, data);
928
929 if (data->force_pte && ctx->level < KVM_PGTABLE_LAST_LEVEL)
930 return false;
931
932 return kvm_block_mapping_supported(ctx, phys);
933 }
934
stage2_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx * ctx,struct stage2_map_data * data)935 static int stage2_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx,
936 struct stage2_map_data *data)
937 {
938 kvm_pte_t new;
939 u64 phys = stage2_map_walker_phys_addr(ctx, data);
940 u64 granule = kvm_granule_size(ctx->level);
941 struct kvm_pgtable *pgt = data->mmu->pgt;
942 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
943
944 if (!stage2_leaf_mapping_allowed(ctx, data))
945 return -E2BIG;
946
947 if (kvm_phys_is_valid(phys))
948 new = kvm_init_valid_leaf_pte(phys, data->attr, ctx->level);
949 else
950 new = kvm_init_invalid_leaf_owner(data->owner_id);
951
952 /*
953 * Skip updating the PTE if we are trying to recreate the exact
954 * same mapping or only change the access permissions. Instead,
955 * the vCPU will exit one more time from guest if still needed
956 * and then go through the path of relaxing permissions.
957 */
958 if (!stage2_pte_needs_update(ctx->old, new))
959 return -EAGAIN;
960
961 if (!stage2_try_break_pte(ctx, data->mmu))
962 return -EAGAIN;
963
964 /* Perform CMOs before installation of the guest stage-2 PTE */
965 if (!kvm_pgtable_walk_skip_cmo(ctx) && mm_ops->dcache_clean_inval_poc &&
966 stage2_pte_cacheable(pgt, new))
967 mm_ops->dcache_clean_inval_poc(kvm_pte_follow(new, mm_ops),
968 granule);
969
970 if (!kvm_pgtable_walk_skip_cmo(ctx) && mm_ops->icache_inval_pou &&
971 stage2_pte_executable(new))
972 mm_ops->icache_inval_pou(kvm_pte_follow(new, mm_ops), granule);
973
974 stage2_make_pte(ctx, new);
975
976 return 0;
977 }
978
stage2_map_walk_table_pre(const struct kvm_pgtable_visit_ctx * ctx,struct stage2_map_data * data)979 static int stage2_map_walk_table_pre(const struct kvm_pgtable_visit_ctx *ctx,
980 struct stage2_map_data *data)
981 {
982 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
983 kvm_pte_t *childp = kvm_pte_follow(ctx->old, mm_ops);
984 int ret;
985
986 if (!stage2_leaf_mapping_allowed(ctx, data))
987 return 0;
988
989 ret = stage2_map_walker_try_leaf(ctx, data);
990 if (ret)
991 return ret;
992
993 mm_ops->free_unlinked_table(childp, ctx->level);
994 return 0;
995 }
996
stage2_map_walk_leaf(const struct kvm_pgtable_visit_ctx * ctx,struct stage2_map_data * data)997 static int stage2_map_walk_leaf(const struct kvm_pgtable_visit_ctx *ctx,
998 struct stage2_map_data *data)
999 {
1000 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
1001 kvm_pte_t *childp, new;
1002 int ret;
1003
1004 ret = stage2_map_walker_try_leaf(ctx, data);
1005 if (ret != -E2BIG)
1006 return ret;
1007
1008 if (WARN_ON(ctx->level == KVM_PGTABLE_LAST_LEVEL))
1009 return -EINVAL;
1010
1011 if (!data->memcache)
1012 return -ENOMEM;
1013
1014 childp = mm_ops->zalloc_page(data->memcache);
1015 if (!childp)
1016 return -ENOMEM;
1017
1018 if (!stage2_try_break_pte(ctx, data->mmu)) {
1019 mm_ops->put_page(childp);
1020 return -EAGAIN;
1021 }
1022
1023 /*
1024 * If we've run into an existing block mapping then replace it with
1025 * a table. Accesses beyond 'end' that fall within the new table
1026 * will be mapped lazily.
1027 */
1028 new = kvm_init_table_pte(childp, mm_ops);
1029 stage2_make_pte(ctx, new);
1030
1031 return 0;
1032 }
1033
1034 /*
1035 * The TABLE_PRE callback runs for table entries on the way down, looking
1036 * for table entries which we could conceivably replace with a block entry
1037 * for this mapping. If it finds one it replaces the entry and calls
1038 * kvm_pgtable_mm_ops::free_unlinked_table() to tear down the detached table.
1039 *
1040 * Otherwise, the LEAF callback performs the mapping at the existing leaves
1041 * instead.
1042 */
stage2_map_walker(const struct kvm_pgtable_visit_ctx * ctx,enum kvm_pgtable_walk_flags visit)1043 static int stage2_map_walker(const struct kvm_pgtable_visit_ctx *ctx,
1044 enum kvm_pgtable_walk_flags visit)
1045 {
1046 struct stage2_map_data *data = ctx->arg;
1047
1048 switch (visit) {
1049 case KVM_PGTABLE_WALK_TABLE_PRE:
1050 return stage2_map_walk_table_pre(ctx, data);
1051 case KVM_PGTABLE_WALK_LEAF:
1052 return stage2_map_walk_leaf(ctx, data);
1053 default:
1054 return -EINVAL;
1055 }
1056 }
1057
kvm_pgtable_stage2_map(struct kvm_pgtable * pgt,u64 addr,u64 size,u64 phys,enum kvm_pgtable_prot prot,void * mc,enum kvm_pgtable_walk_flags flags)1058 int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
1059 u64 phys, enum kvm_pgtable_prot prot,
1060 void *mc, enum kvm_pgtable_walk_flags flags)
1061 {
1062 int ret;
1063 struct stage2_map_data map_data = {
1064 .phys = ALIGN_DOWN(phys, PAGE_SIZE),
1065 .mmu = pgt->mmu,
1066 .memcache = mc,
1067 .force_pte = pgt->force_pte_cb && pgt->force_pte_cb(addr, addr + size, prot),
1068 };
1069 struct kvm_pgtable_walker walker = {
1070 .cb = stage2_map_walker,
1071 .flags = flags |
1072 KVM_PGTABLE_WALK_TABLE_PRE |
1073 KVM_PGTABLE_WALK_LEAF,
1074 .arg = &map_data,
1075 };
1076
1077 if (WARN_ON((pgt->flags & KVM_PGTABLE_S2_IDMAP) && (addr != phys)))
1078 return -EINVAL;
1079
1080 ret = stage2_set_prot_attr(pgt, prot, &map_data.attr);
1081 if (ret)
1082 return ret;
1083
1084 ret = kvm_pgtable_walk(pgt, addr, size, &walker);
1085 dsb(ishst);
1086 return ret;
1087 }
1088
kvm_pgtable_stage2_set_owner(struct kvm_pgtable * pgt,u64 addr,u64 size,void * mc,u8 owner_id)1089 int kvm_pgtable_stage2_set_owner(struct kvm_pgtable *pgt, u64 addr, u64 size,
1090 void *mc, u8 owner_id)
1091 {
1092 int ret;
1093 struct stage2_map_data map_data = {
1094 .phys = KVM_PHYS_INVALID,
1095 .mmu = pgt->mmu,
1096 .memcache = mc,
1097 .owner_id = owner_id,
1098 .force_pte = true,
1099 };
1100 struct kvm_pgtable_walker walker = {
1101 .cb = stage2_map_walker,
1102 .flags = KVM_PGTABLE_WALK_TABLE_PRE |
1103 KVM_PGTABLE_WALK_LEAF,
1104 .arg = &map_data,
1105 };
1106
1107 if (owner_id > KVM_MAX_OWNER_ID)
1108 return -EINVAL;
1109
1110 ret = kvm_pgtable_walk(pgt, addr, size, &walker);
1111 return ret;
1112 }
1113
stage2_unmap_walker(const struct kvm_pgtable_visit_ctx * ctx,enum kvm_pgtable_walk_flags visit)1114 static int stage2_unmap_walker(const struct kvm_pgtable_visit_ctx *ctx,
1115 enum kvm_pgtable_walk_flags visit)
1116 {
1117 struct kvm_pgtable *pgt = ctx->arg;
1118 struct kvm_s2_mmu *mmu = pgt->mmu;
1119 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
1120 kvm_pte_t *childp = NULL;
1121 bool need_flush = false;
1122
1123 if (!kvm_pte_valid(ctx->old)) {
1124 if (stage2_pte_is_counted(ctx->old)) {
1125 kvm_clear_pte(ctx->ptep);
1126 mm_ops->put_page(ctx->ptep);
1127 }
1128 return 0;
1129 }
1130
1131 if (kvm_pte_table(ctx->old, ctx->level)) {
1132 childp = kvm_pte_follow(ctx->old, mm_ops);
1133
1134 if (mm_ops->page_count(childp) != 1)
1135 return 0;
1136 } else if (stage2_pte_cacheable(pgt, ctx->old)) {
1137 need_flush = !stage2_has_fwb(pgt);
1138 }
1139
1140 /*
1141 * This is similar to the map() path in that we unmap the entire
1142 * block entry and rely on the remaining portions being faulted
1143 * back lazily.
1144 */
1145 stage2_unmap_put_pte(ctx, mmu, mm_ops);
1146
1147 if (need_flush && mm_ops->dcache_clean_inval_poc)
1148 mm_ops->dcache_clean_inval_poc(kvm_pte_follow(ctx->old, mm_ops),
1149 kvm_granule_size(ctx->level));
1150
1151 if (childp)
1152 mm_ops->put_page(childp);
1153
1154 return 0;
1155 }
1156
kvm_pgtable_stage2_unmap(struct kvm_pgtable * pgt,u64 addr,u64 size)1157 int kvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size)
1158 {
1159 int ret;
1160 struct kvm_pgtable_walker walker = {
1161 .cb = stage2_unmap_walker,
1162 .arg = pgt,
1163 .flags = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST,
1164 };
1165
1166 ret = kvm_pgtable_walk(pgt, addr, size, &walker);
1167 if (stage2_unmap_defer_tlb_flush(pgt))
1168 /* Perform the deferred TLB invalidations */
1169 kvm_tlb_flush_vmid_range(pgt->mmu, addr, size);
1170
1171 return ret;
1172 }
1173
1174 struct stage2_attr_data {
1175 kvm_pte_t attr_set;
1176 kvm_pte_t attr_clr;
1177 kvm_pte_t pte;
1178 s8 level;
1179 };
1180
stage2_attr_walker(const struct kvm_pgtable_visit_ctx * ctx,enum kvm_pgtable_walk_flags visit)1181 static int stage2_attr_walker(const struct kvm_pgtable_visit_ctx *ctx,
1182 enum kvm_pgtable_walk_flags visit)
1183 {
1184 kvm_pte_t pte = ctx->old;
1185 struct stage2_attr_data *data = ctx->arg;
1186 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
1187
1188 if (!kvm_pte_valid(ctx->old))
1189 return -EAGAIN;
1190
1191 data->level = ctx->level;
1192 data->pte = pte;
1193 pte &= ~data->attr_clr;
1194 pte |= data->attr_set;
1195
1196 /*
1197 * We may race with the CPU trying to set the access flag here,
1198 * but worst-case the access flag update gets lost and will be
1199 * set on the next access instead.
1200 */
1201 if (data->pte != pte) {
1202 /*
1203 * Invalidate instruction cache before updating the guest
1204 * stage-2 PTE if we are going to add executable permission.
1205 */
1206 if (mm_ops->icache_inval_pou &&
1207 stage2_pte_executable(pte) && !stage2_pte_executable(ctx->old))
1208 mm_ops->icache_inval_pou(kvm_pte_follow(pte, mm_ops),
1209 kvm_granule_size(ctx->level));
1210
1211 if (!stage2_try_set_pte(ctx, pte))
1212 return -EAGAIN;
1213 }
1214
1215 return 0;
1216 }
1217
stage2_update_leaf_attrs(struct kvm_pgtable * pgt,u64 addr,u64 size,kvm_pte_t attr_set,kvm_pte_t attr_clr,kvm_pte_t * orig_pte,s8 * level,enum kvm_pgtable_walk_flags flags)1218 static int stage2_update_leaf_attrs(struct kvm_pgtable *pgt, u64 addr,
1219 u64 size, kvm_pte_t attr_set,
1220 kvm_pte_t attr_clr, kvm_pte_t *orig_pte,
1221 s8 *level, enum kvm_pgtable_walk_flags flags)
1222 {
1223 int ret;
1224 kvm_pte_t attr_mask = KVM_PTE_LEAF_ATTR_LO | KVM_PTE_LEAF_ATTR_HI;
1225 struct stage2_attr_data data = {
1226 .attr_set = attr_set & attr_mask,
1227 .attr_clr = attr_clr & attr_mask,
1228 };
1229 struct kvm_pgtable_walker walker = {
1230 .cb = stage2_attr_walker,
1231 .arg = &data,
1232 .flags = flags | KVM_PGTABLE_WALK_LEAF,
1233 };
1234
1235 ret = kvm_pgtable_walk(pgt, addr, size, &walker);
1236 if (ret)
1237 return ret;
1238
1239 if (orig_pte)
1240 *orig_pte = data.pte;
1241
1242 if (level)
1243 *level = data.level;
1244 return 0;
1245 }
1246
kvm_pgtable_stage2_wrprotect(struct kvm_pgtable * pgt,u64 addr,u64 size)1247 int kvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size)
1248 {
1249 return stage2_update_leaf_attrs(pgt, addr, size, 0,
1250 KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W,
1251 NULL, NULL, 0);
1252 }
1253
kvm_pgtable_stage2_mkyoung(struct kvm_pgtable * pgt,u64 addr)1254 kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr)
1255 {
1256 kvm_pte_t pte = 0;
1257 int ret;
1258
1259 ret = stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0,
1260 &pte, NULL,
1261 KVM_PGTABLE_WALK_HANDLE_FAULT |
1262 KVM_PGTABLE_WALK_SHARED);
1263 if (!ret)
1264 dsb(ishst);
1265
1266 return pte;
1267 }
1268
1269 struct stage2_age_data {
1270 bool mkold;
1271 bool young;
1272 };
1273
stage2_age_walker(const struct kvm_pgtable_visit_ctx * ctx,enum kvm_pgtable_walk_flags visit)1274 static int stage2_age_walker(const struct kvm_pgtable_visit_ctx *ctx,
1275 enum kvm_pgtable_walk_flags visit)
1276 {
1277 kvm_pte_t new = ctx->old & ~KVM_PTE_LEAF_ATTR_LO_S2_AF;
1278 struct stage2_age_data *data = ctx->arg;
1279
1280 if (!kvm_pte_valid(ctx->old) || new == ctx->old)
1281 return 0;
1282
1283 data->young = true;
1284
1285 /*
1286 * stage2_age_walker() is always called while holding the MMU lock for
1287 * write, so this will always succeed. Nonetheless, this deliberately
1288 * follows the race detection pattern of the other stage-2 walkers in
1289 * case the locking mechanics of the MMU notifiers is ever changed.
1290 */
1291 if (data->mkold && !stage2_try_set_pte(ctx, new))
1292 return -EAGAIN;
1293
1294 /*
1295 * "But where's the TLBI?!", you scream.
1296 * "Over in the core code", I sigh.
1297 *
1298 * See the '->clear_flush_young()' callback on the KVM mmu notifier.
1299 */
1300 return 0;
1301 }
1302
kvm_pgtable_stage2_test_clear_young(struct kvm_pgtable * pgt,u64 addr,u64 size,bool mkold)1303 bool kvm_pgtable_stage2_test_clear_young(struct kvm_pgtable *pgt, u64 addr,
1304 u64 size, bool mkold)
1305 {
1306 struct stage2_age_data data = {
1307 .mkold = mkold,
1308 };
1309 struct kvm_pgtable_walker walker = {
1310 .cb = stage2_age_walker,
1311 .arg = &data,
1312 .flags = KVM_PGTABLE_WALK_LEAF,
1313 };
1314
1315 WARN_ON(kvm_pgtable_walk(pgt, addr, size, &walker));
1316 return data.young;
1317 }
1318
kvm_pgtable_stage2_relax_perms(struct kvm_pgtable * pgt,u64 addr,enum kvm_pgtable_prot prot)1319 int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr,
1320 enum kvm_pgtable_prot prot)
1321 {
1322 int ret;
1323 s8 level;
1324 kvm_pte_t set = 0, clr = 0;
1325
1326 if (prot & KVM_PTE_LEAF_ATTR_HI_SW)
1327 return -EINVAL;
1328
1329 if (prot & KVM_PGTABLE_PROT_R)
1330 set |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R;
1331
1332 if (prot & KVM_PGTABLE_PROT_W)
1333 set |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W;
1334
1335 if (prot & KVM_PGTABLE_PROT_X)
1336 clr |= KVM_PTE_LEAF_ATTR_HI_S2_XN;
1337
1338 ret = stage2_update_leaf_attrs(pgt, addr, 1, set, clr, NULL, &level,
1339 KVM_PGTABLE_WALK_HANDLE_FAULT |
1340 KVM_PGTABLE_WALK_SHARED);
1341 if (!ret || ret == -EAGAIN)
1342 kvm_call_hyp(__kvm_tlb_flush_vmid_ipa_nsh, pgt->mmu, addr, level);
1343 return ret;
1344 }
1345
stage2_flush_walker(const struct kvm_pgtable_visit_ctx * ctx,enum kvm_pgtable_walk_flags visit)1346 static int stage2_flush_walker(const struct kvm_pgtable_visit_ctx *ctx,
1347 enum kvm_pgtable_walk_flags visit)
1348 {
1349 struct kvm_pgtable *pgt = ctx->arg;
1350 struct kvm_pgtable_mm_ops *mm_ops = pgt->mm_ops;
1351
1352 if (!kvm_pte_valid(ctx->old) || !stage2_pte_cacheable(pgt, ctx->old))
1353 return 0;
1354
1355 if (mm_ops->dcache_clean_inval_poc)
1356 mm_ops->dcache_clean_inval_poc(kvm_pte_follow(ctx->old, mm_ops),
1357 kvm_granule_size(ctx->level));
1358 return 0;
1359 }
1360
kvm_pgtable_stage2_flush(struct kvm_pgtable * pgt,u64 addr,u64 size)1361 int kvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size)
1362 {
1363 struct kvm_pgtable_walker walker = {
1364 .cb = stage2_flush_walker,
1365 .flags = KVM_PGTABLE_WALK_LEAF,
1366 .arg = pgt,
1367 };
1368
1369 if (stage2_has_fwb(pgt))
1370 return 0;
1371
1372 return kvm_pgtable_walk(pgt, addr, size, &walker);
1373 }
1374
kvm_pgtable_stage2_create_unlinked(struct kvm_pgtable * pgt,u64 phys,s8 level,enum kvm_pgtable_prot prot,void * mc,bool force_pte)1375 kvm_pte_t *kvm_pgtable_stage2_create_unlinked(struct kvm_pgtable *pgt,
1376 u64 phys, s8 level,
1377 enum kvm_pgtable_prot prot,
1378 void *mc, bool force_pte)
1379 {
1380 struct stage2_map_data map_data = {
1381 .phys = phys,
1382 .mmu = pgt->mmu,
1383 .memcache = mc,
1384 .force_pte = force_pte,
1385 };
1386 struct kvm_pgtable_walker walker = {
1387 .cb = stage2_map_walker,
1388 .flags = KVM_PGTABLE_WALK_LEAF |
1389 KVM_PGTABLE_WALK_SKIP_BBM_TLBI |
1390 KVM_PGTABLE_WALK_SKIP_CMO,
1391 .arg = &map_data,
1392 };
1393 /*
1394 * The input address (.addr) is irrelevant for walking an
1395 * unlinked table. Construct an ambiguous IA range to map
1396 * kvm_granule_size(level) worth of memory.
1397 */
1398 struct kvm_pgtable_walk_data data = {
1399 .walker = &walker,
1400 .addr = 0,
1401 .end = kvm_granule_size(level),
1402 };
1403 struct kvm_pgtable_mm_ops *mm_ops = pgt->mm_ops;
1404 kvm_pte_t *pgtable;
1405 int ret;
1406
1407 if (!IS_ALIGNED(phys, kvm_granule_size(level)))
1408 return ERR_PTR(-EINVAL);
1409
1410 ret = stage2_set_prot_attr(pgt, prot, &map_data.attr);
1411 if (ret)
1412 return ERR_PTR(ret);
1413
1414 pgtable = mm_ops->zalloc_page(mc);
1415 if (!pgtable)
1416 return ERR_PTR(-ENOMEM);
1417
1418 ret = __kvm_pgtable_walk(&data, mm_ops, (kvm_pteref_t)pgtable,
1419 level + 1);
1420 if (ret) {
1421 kvm_pgtable_stage2_free_unlinked(mm_ops, pgtable, level);
1422 return ERR_PTR(ret);
1423 }
1424
1425 return pgtable;
1426 }
1427
1428 /*
1429 * Get the number of page-tables needed to replace a block with a
1430 * fully populated tree up to the PTE entries. Note that @level is
1431 * interpreted as in "level @level entry".
1432 */
stage2_block_get_nr_page_tables(s8 level)1433 static int stage2_block_get_nr_page_tables(s8 level)
1434 {
1435 switch (level) {
1436 case 1:
1437 return PTRS_PER_PTE + 1;
1438 case 2:
1439 return 1;
1440 case 3:
1441 return 0;
1442 default:
1443 WARN_ON_ONCE(level < KVM_PGTABLE_MIN_BLOCK_LEVEL ||
1444 level > KVM_PGTABLE_LAST_LEVEL);
1445 return -EINVAL;
1446 };
1447 }
1448
stage2_split_walker(const struct kvm_pgtable_visit_ctx * ctx,enum kvm_pgtable_walk_flags visit)1449 static int stage2_split_walker(const struct kvm_pgtable_visit_ctx *ctx,
1450 enum kvm_pgtable_walk_flags visit)
1451 {
1452 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
1453 struct kvm_mmu_memory_cache *mc = ctx->arg;
1454 struct kvm_s2_mmu *mmu;
1455 kvm_pte_t pte = ctx->old, new, *childp;
1456 enum kvm_pgtable_prot prot;
1457 s8 level = ctx->level;
1458 bool force_pte;
1459 int nr_pages;
1460 u64 phys;
1461
1462 /* No huge-pages exist at the last level */
1463 if (level == KVM_PGTABLE_LAST_LEVEL)
1464 return 0;
1465
1466 /* We only split valid block mappings */
1467 if (!kvm_pte_valid(pte))
1468 return 0;
1469
1470 nr_pages = stage2_block_get_nr_page_tables(level);
1471 if (nr_pages < 0)
1472 return nr_pages;
1473
1474 if (mc->nobjs >= nr_pages) {
1475 /* Build a tree mapped down to the PTE granularity. */
1476 force_pte = true;
1477 } else {
1478 /*
1479 * Don't force PTEs, so create_unlinked() below does
1480 * not populate the tree up to the PTE level. The
1481 * consequence is that the call will require a single
1482 * page of level 2 entries at level 1, or a single
1483 * page of PTEs at level 2. If we are at level 1, the
1484 * PTEs will be created recursively.
1485 */
1486 force_pte = false;
1487 nr_pages = 1;
1488 }
1489
1490 if (mc->nobjs < nr_pages)
1491 return -ENOMEM;
1492
1493 mmu = container_of(mc, struct kvm_s2_mmu, split_page_cache);
1494 phys = kvm_pte_to_phys(pte);
1495 prot = kvm_pgtable_stage2_pte_prot(pte);
1496
1497 childp = kvm_pgtable_stage2_create_unlinked(mmu->pgt, phys,
1498 level, prot, mc, force_pte);
1499 if (IS_ERR(childp))
1500 return PTR_ERR(childp);
1501
1502 if (!stage2_try_break_pte(ctx, mmu)) {
1503 kvm_pgtable_stage2_free_unlinked(mm_ops, childp, level);
1504 return -EAGAIN;
1505 }
1506
1507 /*
1508 * Note, the contents of the page table are guaranteed to be made
1509 * visible before the new PTE is assigned because stage2_make_pte()
1510 * writes the PTE using smp_store_release().
1511 */
1512 new = kvm_init_table_pte(childp, mm_ops);
1513 stage2_make_pte(ctx, new);
1514 dsb(ishst);
1515 return 0;
1516 }
1517
kvm_pgtable_stage2_split(struct kvm_pgtable * pgt,u64 addr,u64 size,struct kvm_mmu_memory_cache * mc)1518 int kvm_pgtable_stage2_split(struct kvm_pgtable *pgt, u64 addr, u64 size,
1519 struct kvm_mmu_memory_cache *mc)
1520 {
1521 struct kvm_pgtable_walker walker = {
1522 .cb = stage2_split_walker,
1523 .flags = KVM_PGTABLE_WALK_LEAF,
1524 .arg = mc,
1525 };
1526
1527 return kvm_pgtable_walk(pgt, addr, size, &walker);
1528 }
1529
__kvm_pgtable_stage2_init(struct kvm_pgtable * pgt,struct kvm_s2_mmu * mmu,struct kvm_pgtable_mm_ops * mm_ops,enum kvm_pgtable_stage2_flags flags,kvm_pgtable_force_pte_cb_t force_pte_cb)1530 int __kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu,
1531 struct kvm_pgtable_mm_ops *mm_ops,
1532 enum kvm_pgtable_stage2_flags flags,
1533 kvm_pgtable_force_pte_cb_t force_pte_cb)
1534 {
1535 size_t pgd_sz;
1536 u64 vtcr = mmu->vtcr;
1537 u32 ia_bits = VTCR_EL2_IPA(vtcr);
1538 u32 sl0 = FIELD_GET(VTCR_EL2_SL0_MASK, vtcr);
1539 s8 start_level = VTCR_EL2_TGRAN_SL0_BASE - sl0;
1540
1541 pgd_sz = kvm_pgd_pages(ia_bits, start_level) * PAGE_SIZE;
1542 pgt->pgd = (kvm_pteref_t)mm_ops->zalloc_pages_exact(pgd_sz);
1543 if (!pgt->pgd)
1544 return -ENOMEM;
1545
1546 pgt->ia_bits = ia_bits;
1547 pgt->start_level = start_level;
1548 pgt->mm_ops = mm_ops;
1549 pgt->mmu = mmu;
1550 pgt->flags = flags;
1551 pgt->force_pte_cb = force_pte_cb;
1552
1553 /* Ensure zeroed PGD pages are visible to the hardware walker */
1554 dsb(ishst);
1555 return 0;
1556 }
1557
kvm_pgtable_stage2_pgd_size(u64 vtcr)1558 size_t kvm_pgtable_stage2_pgd_size(u64 vtcr)
1559 {
1560 u32 ia_bits = VTCR_EL2_IPA(vtcr);
1561 u32 sl0 = FIELD_GET(VTCR_EL2_SL0_MASK, vtcr);
1562 s8 start_level = VTCR_EL2_TGRAN_SL0_BASE - sl0;
1563
1564 return kvm_pgd_pages(ia_bits, start_level) * PAGE_SIZE;
1565 }
1566
stage2_free_walker(const struct kvm_pgtable_visit_ctx * ctx,enum kvm_pgtable_walk_flags visit)1567 static int stage2_free_walker(const struct kvm_pgtable_visit_ctx *ctx,
1568 enum kvm_pgtable_walk_flags visit)
1569 {
1570 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
1571
1572 if (!stage2_pte_is_counted(ctx->old))
1573 return 0;
1574
1575 mm_ops->put_page(ctx->ptep);
1576
1577 if (kvm_pte_table(ctx->old, ctx->level))
1578 mm_ops->put_page(kvm_pte_follow(ctx->old, mm_ops));
1579
1580 return 0;
1581 }
1582
kvm_pgtable_stage2_destroy(struct kvm_pgtable * pgt)1583 void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt)
1584 {
1585 size_t pgd_sz;
1586 struct kvm_pgtable_walker walker = {
1587 .cb = stage2_free_walker,
1588 .flags = KVM_PGTABLE_WALK_LEAF |
1589 KVM_PGTABLE_WALK_TABLE_POST,
1590 };
1591
1592 WARN_ON(kvm_pgtable_walk(pgt, 0, BIT(pgt->ia_bits), &walker));
1593 pgd_sz = kvm_pgd_pages(pgt->ia_bits, pgt->start_level) * PAGE_SIZE;
1594 pgt->mm_ops->free_pages_exact(kvm_dereference_pteref(&walker, pgt->pgd), pgd_sz);
1595 pgt->pgd = NULL;
1596 }
1597
kvm_pgtable_stage2_free_unlinked(struct kvm_pgtable_mm_ops * mm_ops,void * pgtable,s8 level)1598 void kvm_pgtable_stage2_free_unlinked(struct kvm_pgtable_mm_ops *mm_ops, void *pgtable, s8 level)
1599 {
1600 kvm_pteref_t ptep = (kvm_pteref_t)pgtable;
1601 struct kvm_pgtable_walker walker = {
1602 .cb = stage2_free_walker,
1603 .flags = KVM_PGTABLE_WALK_LEAF |
1604 KVM_PGTABLE_WALK_TABLE_POST,
1605 };
1606 struct kvm_pgtable_walk_data data = {
1607 .walker = &walker,
1608
1609 /*
1610 * At this point the IPA really doesn't matter, as the page
1611 * table being traversed has already been removed from the stage
1612 * 2. Set an appropriate range to cover the entire page table.
1613 */
1614 .addr = 0,
1615 .end = kvm_granule_size(level),
1616 };
1617
1618 WARN_ON(__kvm_pgtable_walk(&data, mm_ops, ptep, level + 1));
1619
1620 WARN_ON(mm_ops->page_count(pgtable) != 1);
1621 mm_ops->put_page(pgtable);
1622 }
1623