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fe5db27d BG |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | ||
02c00b3a BG |
3 | #include "mmu.h" |
4 | #include "mmu_internal.h" | |
bb18842e | 5 | #include "mmutrace.h" |
2f2fad08 | 6 | #include "tdp_iter.h" |
fe5db27d | 7 | #include "tdp_mmu.h" |
02c00b3a | 8 | #include "spte.h" |
fe5db27d | 9 | |
95fb5b02 | 10 | #ifdef CONFIG_X86_64 |
fe5db27d | 11 | static bool __read_mostly tdp_mmu_enabled = false; |
95fb5b02 BG |
12 | module_param_named(tdp_mmu, tdp_mmu_enabled, bool, 0644); |
13 | #endif | |
fe5db27d BG |
14 | |
15 | static bool is_tdp_mmu_enabled(void) | |
16 | { | |
17 | #ifdef CONFIG_X86_64 | |
18 | return tdp_enabled && READ_ONCE(tdp_mmu_enabled); | |
19 | #else | |
20 | return false; | |
21 | #endif /* CONFIG_X86_64 */ | |
22 | } | |
23 | ||
24 | /* Initializes the TDP MMU for the VM, if enabled. */ | |
25 | void kvm_mmu_init_tdp_mmu(struct kvm *kvm) | |
26 | { | |
27 | if (!is_tdp_mmu_enabled()) | |
28 | return; | |
29 | ||
30 | /* This should not be changed for the lifetime of the VM. */ | |
31 | kvm->arch.tdp_mmu_enabled = true; | |
02c00b3a BG |
32 | |
33 | INIT_LIST_HEAD(&kvm->arch.tdp_mmu_roots); | |
89c0fd49 | 34 | INIT_LIST_HEAD(&kvm->arch.tdp_mmu_pages); |
fe5db27d BG |
35 | } |
36 | ||
37 | void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm) | |
38 | { | |
39 | if (!kvm->arch.tdp_mmu_enabled) | |
40 | return; | |
02c00b3a BG |
41 | |
42 | WARN_ON(!list_empty(&kvm->arch.tdp_mmu_roots)); | |
43 | } | |
44 | ||
45 | #define for_each_tdp_mmu_root(_kvm, _root) \ | |
46 | list_for_each_entry(_root, &_kvm->arch.tdp_mmu_roots, link) | |
47 | ||
48 | bool is_tdp_mmu_root(struct kvm *kvm, hpa_t hpa) | |
49 | { | |
50 | struct kvm_mmu_page *sp; | |
51 | ||
c887c9b9 PB |
52 | if (!kvm->arch.tdp_mmu_enabled) |
53 | return false; | |
54 | if (WARN_ON(!VALID_PAGE(hpa))) | |
55 | return false; | |
56 | ||
02c00b3a | 57 | sp = to_shadow_page(hpa); |
c887c9b9 PB |
58 | if (WARN_ON(!sp)) |
59 | return false; | |
02c00b3a BG |
60 | |
61 | return sp->tdp_mmu_page && sp->root_count; | |
62 | } | |
63 | ||
faaf05b0 | 64 | static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, |
063afacd | 65 | gfn_t start, gfn_t end, bool can_yield); |
faaf05b0 | 66 | |
02c00b3a BG |
67 | void kvm_tdp_mmu_free_root(struct kvm *kvm, struct kvm_mmu_page *root) |
68 | { | |
339f5a7f | 69 | gfn_t max_gfn = 1ULL << (shadow_phys_bits - PAGE_SHIFT); |
faaf05b0 | 70 | |
02c00b3a BG |
71 | lockdep_assert_held(&kvm->mmu_lock); |
72 | ||
73 | WARN_ON(root->root_count); | |
74 | WARN_ON(!root->tdp_mmu_page); | |
75 | ||
76 | list_del(&root->link); | |
77 | ||
063afacd | 78 | zap_gfn_range(kvm, root, 0, max_gfn, false); |
faaf05b0 | 79 | |
02c00b3a BG |
80 | free_page((unsigned long)root->spt); |
81 | kmem_cache_free(mmu_page_header_cache, root); | |
82 | } | |
83 | ||
84 | static union kvm_mmu_page_role page_role_for_level(struct kvm_vcpu *vcpu, | |
85 | int level) | |
86 | { | |
87 | union kvm_mmu_page_role role; | |
88 | ||
89 | role = vcpu->arch.mmu->mmu_role.base; | |
90 | role.level = level; | |
91 | role.direct = true; | |
92 | role.gpte_is_8_bytes = true; | |
93 | role.access = ACC_ALL; | |
94 | ||
95 | return role; | |
96 | } | |
97 | ||
98 | static struct kvm_mmu_page *alloc_tdp_mmu_page(struct kvm_vcpu *vcpu, gfn_t gfn, | |
99 | int level) | |
100 | { | |
101 | struct kvm_mmu_page *sp; | |
102 | ||
103 | sp = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache); | |
104 | sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache); | |
105 | set_page_private(virt_to_page(sp->spt), (unsigned long)sp); | |
106 | ||
107 | sp->role.word = page_role_for_level(vcpu, level).word; | |
108 | sp->gfn = gfn; | |
109 | sp->tdp_mmu_page = true; | |
110 | ||
111 | return sp; | |
112 | } | |
113 | ||
114 | static struct kvm_mmu_page *get_tdp_mmu_vcpu_root(struct kvm_vcpu *vcpu) | |
115 | { | |
116 | union kvm_mmu_page_role role; | |
117 | struct kvm *kvm = vcpu->kvm; | |
118 | struct kvm_mmu_page *root; | |
119 | ||
120 | role = page_role_for_level(vcpu, vcpu->arch.mmu->shadow_root_level); | |
121 | ||
122 | spin_lock(&kvm->mmu_lock); | |
123 | ||
124 | /* Check for an existing root before allocating a new one. */ | |
125 | for_each_tdp_mmu_root(kvm, root) { | |
126 | if (root->role.word == role.word) { | |
127 | kvm_mmu_get_root(kvm, root); | |
128 | spin_unlock(&kvm->mmu_lock); | |
129 | return root; | |
130 | } | |
131 | } | |
132 | ||
133 | root = alloc_tdp_mmu_page(vcpu, 0, vcpu->arch.mmu->shadow_root_level); | |
134 | root->root_count = 1; | |
135 | ||
136 | list_add(&root->link, &kvm->arch.tdp_mmu_roots); | |
137 | ||
138 | spin_unlock(&kvm->mmu_lock); | |
139 | ||
140 | return root; | |
141 | } | |
142 | ||
143 | hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu) | |
144 | { | |
145 | struct kvm_mmu_page *root; | |
146 | ||
147 | root = get_tdp_mmu_vcpu_root(vcpu); | |
148 | if (!root) | |
149 | return INVALID_PAGE; | |
150 | ||
151 | return __pa(root->spt); | |
fe5db27d | 152 | } |
2f2fad08 BG |
153 | |
154 | static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn, | |
155 | u64 old_spte, u64 new_spte, int level); | |
156 | ||
faaf05b0 BG |
157 | static int kvm_mmu_page_as_id(struct kvm_mmu_page *sp) |
158 | { | |
159 | return sp->role.smm ? 1 : 0; | |
160 | } | |
161 | ||
f8e14497 BG |
162 | static void handle_changed_spte_acc_track(u64 old_spte, u64 new_spte, int level) |
163 | { | |
164 | bool pfn_changed = spte_to_pfn(old_spte) != spte_to_pfn(new_spte); | |
165 | ||
166 | if (!is_shadow_present_pte(old_spte) || !is_last_spte(old_spte, level)) | |
167 | return; | |
168 | ||
169 | if (is_accessed_spte(old_spte) && | |
170 | (!is_accessed_spte(new_spte) || pfn_changed)) | |
171 | kvm_set_pfn_accessed(spte_to_pfn(old_spte)); | |
172 | } | |
173 | ||
a6a0b05d BG |
174 | static void handle_changed_spte_dirty_log(struct kvm *kvm, int as_id, gfn_t gfn, |
175 | u64 old_spte, u64 new_spte, int level) | |
176 | { | |
177 | bool pfn_changed; | |
178 | struct kvm_memory_slot *slot; | |
179 | ||
180 | if (level > PG_LEVEL_4K) | |
181 | return; | |
182 | ||
183 | pfn_changed = spte_to_pfn(old_spte) != spte_to_pfn(new_spte); | |
184 | ||
185 | if ((!is_writable_pte(old_spte) || pfn_changed) && | |
186 | is_writable_pte(new_spte)) { | |
187 | slot = __gfn_to_memslot(__kvm_memslots(kvm, as_id), gfn); | |
188 | mark_page_dirty_in_slot(slot, gfn); | |
189 | } | |
190 | } | |
191 | ||
2f2fad08 BG |
192 | /** |
193 | * handle_changed_spte - handle bookkeeping associated with an SPTE change | |
194 | * @kvm: kvm instance | |
195 | * @as_id: the address space of the paging structure the SPTE was a part of | |
196 | * @gfn: the base GFN that was mapped by the SPTE | |
197 | * @old_spte: The value of the SPTE before the change | |
198 | * @new_spte: The value of the SPTE after the change | |
199 | * @level: the level of the PT the SPTE is part of in the paging structure | |
200 | * | |
201 | * Handle bookkeeping that might result from the modification of a SPTE. | |
202 | * This function must be called for all TDP SPTE modifications. | |
203 | */ | |
204 | static void __handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn, | |
205 | u64 old_spte, u64 new_spte, int level) | |
206 | { | |
207 | bool was_present = is_shadow_present_pte(old_spte); | |
208 | bool is_present = is_shadow_present_pte(new_spte); | |
209 | bool was_leaf = was_present && is_last_spte(old_spte, level); | |
210 | bool is_leaf = is_present && is_last_spte(new_spte, level); | |
211 | bool pfn_changed = spte_to_pfn(old_spte) != spte_to_pfn(new_spte); | |
212 | u64 *pt; | |
89c0fd49 | 213 | struct kvm_mmu_page *sp; |
2f2fad08 BG |
214 | u64 old_child_spte; |
215 | int i; | |
216 | ||
217 | WARN_ON(level > PT64_ROOT_MAX_LEVEL); | |
218 | WARN_ON(level < PG_LEVEL_4K); | |
764388ce | 219 | WARN_ON(gfn & (KVM_PAGES_PER_HPAGE(level) - 1)); |
2f2fad08 BG |
220 | |
221 | /* | |
222 | * If this warning were to trigger it would indicate that there was a | |
223 | * missing MMU notifier or a race with some notifier handler. | |
224 | * A present, leaf SPTE should never be directly replaced with another | |
225 | * present leaf SPTE pointing to a differnt PFN. A notifier handler | |
226 | * should be zapping the SPTE before the main MM's page table is | |
227 | * changed, or the SPTE should be zeroed, and the TLBs flushed by the | |
228 | * thread before replacement. | |
229 | */ | |
230 | if (was_leaf && is_leaf && pfn_changed) { | |
231 | pr_err("Invalid SPTE change: cannot replace a present leaf\n" | |
232 | "SPTE with another present leaf SPTE mapping a\n" | |
233 | "different PFN!\n" | |
234 | "as_id: %d gfn: %llx old_spte: %llx new_spte: %llx level: %d", | |
235 | as_id, gfn, old_spte, new_spte, level); | |
236 | ||
237 | /* | |
238 | * Crash the host to prevent error propagation and guest data | |
239 | * courruption. | |
240 | */ | |
241 | BUG(); | |
242 | } | |
243 | ||
244 | if (old_spte == new_spte) | |
245 | return; | |
246 | ||
247 | /* | |
248 | * The only times a SPTE should be changed from a non-present to | |
249 | * non-present state is when an MMIO entry is installed/modified/ | |
250 | * removed. In that case, there is nothing to do here. | |
251 | */ | |
252 | if (!was_present && !is_present) { | |
253 | /* | |
254 | * If this change does not involve a MMIO SPTE, it is | |
255 | * unexpected. Log the change, though it should not impact the | |
256 | * guest since both the former and current SPTEs are nonpresent. | |
257 | */ | |
258 | if (WARN_ON(!is_mmio_spte(old_spte) && !is_mmio_spte(new_spte))) | |
259 | pr_err("Unexpected SPTE change! Nonpresent SPTEs\n" | |
260 | "should not be replaced with another,\n" | |
261 | "different nonpresent SPTE, unless one or both\n" | |
262 | "are MMIO SPTEs.\n" | |
263 | "as_id: %d gfn: %llx old_spte: %llx new_spte: %llx level: %d", | |
264 | as_id, gfn, old_spte, new_spte, level); | |
265 | return; | |
266 | } | |
267 | ||
268 | ||
269 | if (was_leaf && is_dirty_spte(old_spte) && | |
270 | (!is_dirty_spte(new_spte) || pfn_changed)) | |
271 | kvm_set_pfn_dirty(spte_to_pfn(old_spte)); | |
272 | ||
273 | /* | |
274 | * Recursively handle child PTs if the change removed a subtree from | |
275 | * the paging structure. | |
276 | */ | |
277 | if (was_present && !was_leaf && (pfn_changed || !is_present)) { | |
278 | pt = spte_to_child_pt(old_spte, level); | |
89c0fd49 BG |
279 | sp = sptep_to_sp(pt); |
280 | ||
281 | list_del(&sp->link); | |
2f2fad08 | 282 | |
29cf0f50 BG |
283 | if (sp->lpage_disallowed) |
284 | unaccount_huge_nx_page(kvm, sp); | |
285 | ||
2f2fad08 BG |
286 | for (i = 0; i < PT64_ENT_PER_PAGE; i++) { |
287 | old_child_spte = READ_ONCE(*(pt + i)); | |
288 | WRITE_ONCE(*(pt + i), 0); | |
289 | handle_changed_spte(kvm, as_id, | |
290 | gfn + (i * KVM_PAGES_PER_HPAGE(level - 1)), | |
291 | old_child_spte, 0, level - 1); | |
292 | } | |
293 | ||
294 | kvm_flush_remote_tlbs_with_address(kvm, gfn, | |
295 | KVM_PAGES_PER_HPAGE(level)); | |
296 | ||
297 | free_page((unsigned long)pt); | |
89c0fd49 | 298 | kmem_cache_free(mmu_page_header_cache, sp); |
2f2fad08 BG |
299 | } |
300 | } | |
301 | ||
302 | static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn, | |
303 | u64 old_spte, u64 new_spte, int level) | |
304 | { | |
305 | __handle_changed_spte(kvm, as_id, gfn, old_spte, new_spte, level); | |
f8e14497 | 306 | handle_changed_spte_acc_track(old_spte, new_spte, level); |
a6a0b05d BG |
307 | handle_changed_spte_dirty_log(kvm, as_id, gfn, old_spte, |
308 | new_spte, level); | |
2f2fad08 | 309 | } |
faaf05b0 | 310 | |
f8e14497 | 311 | static inline void __tdp_mmu_set_spte(struct kvm *kvm, struct tdp_iter *iter, |
a6a0b05d BG |
312 | u64 new_spte, bool record_acc_track, |
313 | bool record_dirty_log) | |
faaf05b0 BG |
314 | { |
315 | u64 *root_pt = tdp_iter_root_pt(iter); | |
316 | struct kvm_mmu_page *root = sptep_to_sp(root_pt); | |
317 | int as_id = kvm_mmu_page_as_id(root); | |
318 | ||
f8e14497 BG |
319 | WRITE_ONCE(*iter->sptep, new_spte); |
320 | ||
321 | __handle_changed_spte(kvm, as_id, iter->gfn, iter->old_spte, new_spte, | |
322 | iter->level); | |
323 | if (record_acc_track) | |
324 | handle_changed_spte_acc_track(iter->old_spte, new_spte, | |
325 | iter->level); | |
a6a0b05d BG |
326 | if (record_dirty_log) |
327 | handle_changed_spte_dirty_log(kvm, as_id, iter->gfn, | |
328 | iter->old_spte, new_spte, | |
329 | iter->level); | |
f8e14497 BG |
330 | } |
331 | ||
332 | static inline void tdp_mmu_set_spte(struct kvm *kvm, struct tdp_iter *iter, | |
333 | u64 new_spte) | |
334 | { | |
a6a0b05d | 335 | __tdp_mmu_set_spte(kvm, iter, new_spte, true, true); |
f8e14497 | 336 | } |
faaf05b0 | 337 | |
f8e14497 BG |
338 | static inline void tdp_mmu_set_spte_no_acc_track(struct kvm *kvm, |
339 | struct tdp_iter *iter, | |
340 | u64 new_spte) | |
341 | { | |
a6a0b05d BG |
342 | __tdp_mmu_set_spte(kvm, iter, new_spte, false, true); |
343 | } | |
344 | ||
345 | static inline void tdp_mmu_set_spte_no_dirty_log(struct kvm *kvm, | |
346 | struct tdp_iter *iter, | |
347 | u64 new_spte) | |
348 | { | |
349 | __tdp_mmu_set_spte(kvm, iter, new_spte, true, false); | |
faaf05b0 BG |
350 | } |
351 | ||
352 | #define tdp_root_for_each_pte(_iter, _root, _start, _end) \ | |
353 | for_each_tdp_pte(_iter, _root->spt, _root->role.level, _start, _end) | |
354 | ||
f8e14497 BG |
355 | #define tdp_root_for_each_leaf_pte(_iter, _root, _start, _end) \ |
356 | tdp_root_for_each_pte(_iter, _root, _start, _end) \ | |
357 | if (!is_shadow_present_pte(_iter.old_spte) || \ | |
358 | !is_last_spte(_iter.old_spte, _iter.level)) \ | |
359 | continue; \ | |
360 | else | |
361 | ||
bb18842e BG |
362 | #define tdp_mmu_for_each_pte(_iter, _mmu, _start, _end) \ |
363 | for_each_tdp_pte(_iter, __va(_mmu->root_hpa), \ | |
364 | _mmu->shadow_root_level, _start, _end) | |
365 | ||
faaf05b0 BG |
366 | /* |
367 | * Flush the TLB if the process should drop kvm->mmu_lock. | |
368 | * Return whether the caller still needs to flush the tlb. | |
369 | */ | |
370 | static bool tdp_mmu_iter_flush_cond_resched(struct kvm *kvm, struct tdp_iter *iter) | |
371 | { | |
372 | if (need_resched() || spin_needbreak(&kvm->mmu_lock)) { | |
373 | kvm_flush_remote_tlbs(kvm); | |
374 | cond_resched_lock(&kvm->mmu_lock); | |
375 | tdp_iter_refresh_walk(iter); | |
376 | return false; | |
377 | } else { | |
378 | return true; | |
379 | } | |
380 | } | |
381 | ||
a6a0b05d BG |
382 | static void tdp_mmu_iter_cond_resched(struct kvm *kvm, struct tdp_iter *iter) |
383 | { | |
384 | if (need_resched() || spin_needbreak(&kvm->mmu_lock)) { | |
385 | cond_resched_lock(&kvm->mmu_lock); | |
386 | tdp_iter_refresh_walk(iter); | |
387 | } | |
388 | } | |
389 | ||
faaf05b0 BG |
390 | /* |
391 | * Tears down the mappings for the range of gfns, [start, end), and frees the | |
392 | * non-root pages mapping GFNs strictly within that range. Returns true if | |
393 | * SPTEs have been cleared and a TLB flush is needed before releasing the | |
394 | * MMU lock. | |
063afacd BG |
395 | * If can_yield is true, will release the MMU lock and reschedule if the |
396 | * scheduler needs the CPU or there is contention on the MMU lock. If this | |
397 | * function cannot yield, it will not release the MMU lock or reschedule and | |
398 | * the caller must ensure it does not supply too large a GFN range, or the | |
399 | * operation can cause a soft lockup. | |
faaf05b0 BG |
400 | */ |
401 | static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, | |
063afacd | 402 | gfn_t start, gfn_t end, bool can_yield) |
faaf05b0 BG |
403 | { |
404 | struct tdp_iter iter; | |
405 | bool flush_needed = false; | |
406 | ||
407 | tdp_root_for_each_pte(iter, root, start, end) { | |
408 | if (!is_shadow_present_pte(iter.old_spte)) | |
409 | continue; | |
410 | ||
411 | /* | |
412 | * If this is a non-last-level SPTE that covers a larger range | |
413 | * than should be zapped, continue, and zap the mappings at a | |
414 | * lower level. | |
415 | */ | |
416 | if ((iter.gfn < start || | |
417 | iter.gfn + KVM_PAGES_PER_HPAGE(iter.level) > end) && | |
418 | !is_last_spte(iter.old_spte, iter.level)) | |
419 | continue; | |
420 | ||
421 | tdp_mmu_set_spte(kvm, &iter, 0); | |
422 | ||
063afacd BG |
423 | if (can_yield) |
424 | flush_needed = tdp_mmu_iter_flush_cond_resched(kvm, &iter); | |
425 | else | |
426 | flush_needed = true; | |
faaf05b0 BG |
427 | } |
428 | return flush_needed; | |
429 | } | |
430 | ||
431 | /* | |
432 | * Tears down the mappings for the range of gfns, [start, end), and frees the | |
433 | * non-root pages mapping GFNs strictly within that range. Returns true if | |
434 | * SPTEs have been cleared and a TLB flush is needed before releasing the | |
435 | * MMU lock. | |
436 | */ | |
437 | bool kvm_tdp_mmu_zap_gfn_range(struct kvm *kvm, gfn_t start, gfn_t end) | |
438 | { | |
439 | struct kvm_mmu_page *root; | |
440 | bool flush = false; | |
441 | ||
442 | for_each_tdp_mmu_root(kvm, root) { | |
443 | /* | |
444 | * Take a reference on the root so that it cannot be freed if | |
445 | * this thread releases the MMU lock and yields in this loop. | |
446 | */ | |
447 | kvm_mmu_get_root(kvm, root); | |
448 | ||
063afacd | 449 | flush |= zap_gfn_range(kvm, root, start, end, true); |
faaf05b0 BG |
450 | |
451 | kvm_mmu_put_root(kvm, root); | |
452 | } | |
453 | ||
454 | return flush; | |
455 | } | |
456 | ||
457 | void kvm_tdp_mmu_zap_all(struct kvm *kvm) | |
458 | { | |
339f5a7f | 459 | gfn_t max_gfn = 1ULL << (shadow_phys_bits - PAGE_SHIFT); |
faaf05b0 BG |
460 | bool flush; |
461 | ||
462 | flush = kvm_tdp_mmu_zap_gfn_range(kvm, 0, max_gfn); | |
463 | if (flush) | |
464 | kvm_flush_remote_tlbs(kvm); | |
465 | } | |
bb18842e BG |
466 | |
467 | /* | |
468 | * Installs a last-level SPTE to handle a TDP page fault. | |
469 | * (NPT/EPT violation/misconfiguration) | |
470 | */ | |
471 | static int tdp_mmu_map_handle_target_level(struct kvm_vcpu *vcpu, int write, | |
472 | int map_writable, | |
473 | struct tdp_iter *iter, | |
474 | kvm_pfn_t pfn, bool prefault) | |
475 | { | |
476 | u64 new_spte; | |
477 | int ret = 0; | |
478 | int make_spte_ret = 0; | |
479 | ||
480 | if (unlikely(is_noslot_pfn(pfn))) { | |
481 | new_spte = make_mmio_spte(vcpu, iter->gfn, ACC_ALL); | |
482 | trace_mark_mmio_spte(iter->sptep, iter->gfn, new_spte); | |
483 | } else | |
484 | make_spte_ret = make_spte(vcpu, ACC_ALL, iter->level, iter->gfn, | |
485 | pfn, iter->old_spte, prefault, true, | |
486 | map_writable, !shadow_accessed_mask, | |
487 | &new_spte); | |
488 | ||
489 | if (new_spte == iter->old_spte) | |
490 | ret = RET_PF_SPURIOUS; | |
491 | else | |
492 | tdp_mmu_set_spte(vcpu->kvm, iter, new_spte); | |
493 | ||
494 | /* | |
495 | * If the page fault was caused by a write but the page is write | |
496 | * protected, emulation is needed. If the emulation was skipped, | |
497 | * the vCPU would have the same fault again. | |
498 | */ | |
499 | if (make_spte_ret & SET_SPTE_WRITE_PROTECTED_PT) { | |
500 | if (write) | |
501 | ret = RET_PF_EMULATE; | |
502 | kvm_make_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu); | |
503 | } | |
504 | ||
505 | /* If a MMIO SPTE is installed, the MMIO will need to be emulated. */ | |
506 | if (unlikely(is_mmio_spte(new_spte))) | |
507 | ret = RET_PF_EMULATE; | |
508 | ||
509 | trace_kvm_mmu_set_spte(iter->level, iter->gfn, iter->sptep); | |
510 | if (!prefault) | |
511 | vcpu->stat.pf_fixed++; | |
512 | ||
513 | return ret; | |
514 | } | |
515 | ||
516 | /* | |
517 | * Handle a TDP page fault (NPT/EPT violation/misconfiguration) by installing | |
518 | * page tables and SPTEs to translate the faulting guest physical address. | |
519 | */ | |
520 | int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code, | |
521 | int map_writable, int max_level, kvm_pfn_t pfn, | |
522 | bool prefault) | |
523 | { | |
524 | bool nx_huge_page_workaround_enabled = is_nx_huge_page_enabled(); | |
525 | bool write = error_code & PFERR_WRITE_MASK; | |
526 | bool exec = error_code & PFERR_FETCH_MASK; | |
527 | bool huge_page_disallowed = exec && nx_huge_page_workaround_enabled; | |
528 | struct kvm_mmu *mmu = vcpu->arch.mmu; | |
529 | struct tdp_iter iter; | |
89c0fd49 | 530 | struct kvm_mmu_page *sp; |
bb18842e BG |
531 | u64 *child_pt; |
532 | u64 new_spte; | |
533 | int ret; | |
534 | gfn_t gfn = gpa >> PAGE_SHIFT; | |
535 | int level; | |
536 | int req_level; | |
537 | ||
538 | if (WARN_ON(!VALID_PAGE(vcpu->arch.mmu->root_hpa))) | |
539 | return RET_PF_RETRY; | |
540 | if (WARN_ON(!is_tdp_mmu_root(vcpu->kvm, vcpu->arch.mmu->root_hpa))) | |
541 | return RET_PF_RETRY; | |
542 | ||
543 | level = kvm_mmu_hugepage_adjust(vcpu, gfn, max_level, &pfn, | |
544 | huge_page_disallowed, &req_level); | |
545 | ||
546 | trace_kvm_mmu_spte_requested(gpa, level, pfn); | |
547 | tdp_mmu_for_each_pte(iter, mmu, gfn, gfn + 1) { | |
548 | if (nx_huge_page_workaround_enabled) | |
549 | disallowed_hugepage_adjust(iter.old_spte, gfn, | |
550 | iter.level, &pfn, &level); | |
551 | ||
552 | if (iter.level == level) | |
553 | break; | |
554 | ||
555 | /* | |
556 | * If there is an SPTE mapping a large page at a higher level | |
557 | * than the target, that SPTE must be cleared and replaced | |
558 | * with a non-leaf SPTE. | |
559 | */ | |
560 | if (is_shadow_present_pte(iter.old_spte) && | |
561 | is_large_pte(iter.old_spte)) { | |
562 | tdp_mmu_set_spte(vcpu->kvm, &iter, 0); | |
563 | ||
564 | kvm_flush_remote_tlbs_with_address(vcpu->kvm, iter.gfn, | |
565 | KVM_PAGES_PER_HPAGE(iter.level)); | |
566 | ||
567 | /* | |
568 | * The iter must explicitly re-read the spte here | |
569 | * because the new value informs the !present | |
570 | * path below. | |
571 | */ | |
572 | iter.old_spte = READ_ONCE(*iter.sptep); | |
573 | } | |
574 | ||
575 | if (!is_shadow_present_pte(iter.old_spte)) { | |
89c0fd49 BG |
576 | sp = alloc_tdp_mmu_page(vcpu, iter.gfn, iter.level); |
577 | list_add(&sp->link, &vcpu->kvm->arch.tdp_mmu_pages); | |
578 | child_pt = sp->spt; | |
bb18842e BG |
579 | clear_page(child_pt); |
580 | new_spte = make_nonleaf_spte(child_pt, | |
581 | !shadow_accessed_mask); | |
582 | ||
583 | trace_kvm_mmu_get_page(sp, true); | |
29cf0f50 BG |
584 | if (huge_page_disallowed && req_level >= iter.level) |
585 | account_huge_nx_page(vcpu->kvm, sp); | |
586 | ||
bb18842e BG |
587 | tdp_mmu_set_spte(vcpu->kvm, &iter, new_spte); |
588 | } | |
589 | } | |
590 | ||
591 | if (WARN_ON(iter.level != level)) | |
592 | return RET_PF_RETRY; | |
593 | ||
594 | ret = tdp_mmu_map_handle_target_level(vcpu, write, map_writable, &iter, | |
595 | pfn, prefault); | |
596 | ||
597 | return ret; | |
598 | } | |
063afacd BG |
599 | |
600 | static int kvm_tdp_mmu_handle_hva_range(struct kvm *kvm, unsigned long start, | |
601 | unsigned long end, unsigned long data, | |
602 | int (*handler)(struct kvm *kvm, struct kvm_memory_slot *slot, | |
603 | struct kvm_mmu_page *root, gfn_t start, | |
604 | gfn_t end, unsigned long data)) | |
605 | { | |
606 | struct kvm_memslots *slots; | |
607 | struct kvm_memory_slot *memslot; | |
608 | struct kvm_mmu_page *root; | |
609 | int ret = 0; | |
610 | int as_id; | |
611 | ||
612 | for_each_tdp_mmu_root(kvm, root) { | |
613 | /* | |
614 | * Take a reference on the root so that it cannot be freed if | |
615 | * this thread releases the MMU lock and yields in this loop. | |
616 | */ | |
617 | kvm_mmu_get_root(kvm, root); | |
618 | ||
619 | as_id = kvm_mmu_page_as_id(root); | |
620 | slots = __kvm_memslots(kvm, as_id); | |
621 | kvm_for_each_memslot(memslot, slots) { | |
622 | unsigned long hva_start, hva_end; | |
623 | gfn_t gfn_start, gfn_end; | |
624 | ||
625 | hva_start = max(start, memslot->userspace_addr); | |
626 | hva_end = min(end, memslot->userspace_addr + | |
627 | (memslot->npages << PAGE_SHIFT)); | |
628 | if (hva_start >= hva_end) | |
629 | continue; | |
630 | /* | |
631 | * {gfn(page) | page intersects with [hva_start, hva_end)} = | |
632 | * {gfn_start, gfn_start+1, ..., gfn_end-1}. | |
633 | */ | |
634 | gfn_start = hva_to_gfn_memslot(hva_start, memslot); | |
635 | gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot); | |
636 | ||
637 | ret |= handler(kvm, memslot, root, gfn_start, | |
638 | gfn_end, data); | |
639 | } | |
640 | ||
641 | kvm_mmu_put_root(kvm, root); | |
642 | } | |
643 | ||
644 | return ret; | |
645 | } | |
646 | ||
647 | static int zap_gfn_range_hva_wrapper(struct kvm *kvm, | |
648 | struct kvm_memory_slot *slot, | |
649 | struct kvm_mmu_page *root, gfn_t start, | |
650 | gfn_t end, unsigned long unused) | |
651 | { | |
652 | return zap_gfn_range(kvm, root, start, end, false); | |
653 | } | |
654 | ||
655 | int kvm_tdp_mmu_zap_hva_range(struct kvm *kvm, unsigned long start, | |
656 | unsigned long end) | |
657 | { | |
658 | return kvm_tdp_mmu_handle_hva_range(kvm, start, end, 0, | |
659 | zap_gfn_range_hva_wrapper); | |
660 | } | |
f8e14497 BG |
661 | |
662 | /* | |
663 | * Mark the SPTEs range of GFNs [start, end) unaccessed and return non-zero | |
664 | * if any of the GFNs in the range have been accessed. | |
665 | */ | |
666 | static int age_gfn_range(struct kvm *kvm, struct kvm_memory_slot *slot, | |
667 | struct kvm_mmu_page *root, gfn_t start, gfn_t end, | |
668 | unsigned long unused) | |
669 | { | |
670 | struct tdp_iter iter; | |
671 | int young = 0; | |
672 | u64 new_spte = 0; | |
673 | ||
674 | tdp_root_for_each_leaf_pte(iter, root, start, end) { | |
675 | /* | |
676 | * If we have a non-accessed entry we don't need to change the | |
677 | * pte. | |
678 | */ | |
679 | if (!is_accessed_spte(iter.old_spte)) | |
680 | continue; | |
681 | ||
682 | new_spte = iter.old_spte; | |
683 | ||
684 | if (spte_ad_enabled(new_spte)) { | |
685 | clear_bit((ffs(shadow_accessed_mask) - 1), | |
686 | (unsigned long *)&new_spte); | |
687 | } else { | |
688 | /* | |
689 | * Capture the dirty status of the page, so that it doesn't get | |
690 | * lost when the SPTE is marked for access tracking. | |
691 | */ | |
692 | if (is_writable_pte(new_spte)) | |
693 | kvm_set_pfn_dirty(spte_to_pfn(new_spte)); | |
694 | ||
695 | new_spte = mark_spte_for_access_track(new_spte); | |
696 | } | |
a6a0b05d | 697 | new_spte &= ~shadow_dirty_mask; |
f8e14497 BG |
698 | |
699 | tdp_mmu_set_spte_no_acc_track(kvm, &iter, new_spte); | |
700 | young = 1; | |
701 | } | |
702 | ||
703 | return young; | |
704 | } | |
705 | ||
706 | int kvm_tdp_mmu_age_hva_range(struct kvm *kvm, unsigned long start, | |
707 | unsigned long end) | |
708 | { | |
709 | return kvm_tdp_mmu_handle_hva_range(kvm, start, end, 0, | |
710 | age_gfn_range); | |
711 | } | |
712 | ||
713 | static int test_age_gfn(struct kvm *kvm, struct kvm_memory_slot *slot, | |
714 | struct kvm_mmu_page *root, gfn_t gfn, gfn_t unused, | |
715 | unsigned long unused2) | |
716 | { | |
717 | struct tdp_iter iter; | |
718 | ||
719 | tdp_root_for_each_leaf_pte(iter, root, gfn, gfn + 1) | |
720 | if (is_accessed_spte(iter.old_spte)) | |
721 | return 1; | |
722 | ||
723 | return 0; | |
724 | } | |
725 | ||
726 | int kvm_tdp_mmu_test_age_hva(struct kvm *kvm, unsigned long hva) | |
727 | { | |
728 | return kvm_tdp_mmu_handle_hva_range(kvm, hva, hva + 1, 0, | |
729 | test_age_gfn); | |
730 | } | |
1d8dd6b3 BG |
731 | |
732 | /* | |
733 | * Handle the changed_pte MMU notifier for the TDP MMU. | |
734 | * data is a pointer to the new pte_t mapping the HVA specified by the MMU | |
735 | * notifier. | |
736 | * Returns non-zero if a flush is needed before releasing the MMU lock. | |
737 | */ | |
738 | static int set_tdp_spte(struct kvm *kvm, struct kvm_memory_slot *slot, | |
739 | struct kvm_mmu_page *root, gfn_t gfn, gfn_t unused, | |
740 | unsigned long data) | |
741 | { | |
742 | struct tdp_iter iter; | |
743 | pte_t *ptep = (pte_t *)data; | |
744 | kvm_pfn_t new_pfn; | |
745 | u64 new_spte; | |
746 | int need_flush = 0; | |
747 | ||
748 | WARN_ON(pte_huge(*ptep)); | |
749 | ||
750 | new_pfn = pte_pfn(*ptep); | |
751 | ||
752 | tdp_root_for_each_pte(iter, root, gfn, gfn + 1) { | |
753 | if (iter.level != PG_LEVEL_4K) | |
754 | continue; | |
755 | ||
756 | if (!is_shadow_present_pte(iter.old_spte)) | |
757 | break; | |
758 | ||
759 | tdp_mmu_set_spte(kvm, &iter, 0); | |
760 | ||
761 | kvm_flush_remote_tlbs_with_address(kvm, iter.gfn, 1); | |
762 | ||
763 | if (!pte_write(*ptep)) { | |
764 | new_spte = kvm_mmu_changed_pte_notifier_make_spte( | |
765 | iter.old_spte, new_pfn); | |
766 | ||
767 | tdp_mmu_set_spte(kvm, &iter, new_spte); | |
768 | } | |
769 | ||
770 | need_flush = 1; | |
771 | } | |
772 | ||
773 | if (need_flush) | |
774 | kvm_flush_remote_tlbs_with_address(kvm, gfn, 1); | |
775 | ||
776 | return 0; | |
777 | } | |
778 | ||
779 | int kvm_tdp_mmu_set_spte_hva(struct kvm *kvm, unsigned long address, | |
780 | pte_t *host_ptep) | |
781 | { | |
782 | return kvm_tdp_mmu_handle_hva_range(kvm, address, address + 1, | |
783 | (unsigned long)host_ptep, | |
784 | set_tdp_spte); | |
785 | } | |
786 | ||
a6a0b05d BG |
787 | /* |
788 | * Remove write access from all the SPTEs mapping GFNs [start, end). If | |
789 | * skip_4k is set, SPTEs that map 4k pages, will not be write-protected. | |
790 | * Returns true if an SPTE has been changed and the TLBs need to be flushed. | |
791 | */ | |
792 | static bool wrprot_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, | |
793 | gfn_t start, gfn_t end, int min_level) | |
794 | { | |
795 | struct tdp_iter iter; | |
796 | u64 new_spte; | |
797 | bool spte_set = false; | |
798 | ||
799 | BUG_ON(min_level > KVM_MAX_HUGEPAGE_LEVEL); | |
800 | ||
801 | for_each_tdp_pte_min_level(iter, root->spt, root->role.level, | |
802 | min_level, start, end) { | |
803 | if (!is_shadow_present_pte(iter.old_spte) || | |
804 | !is_last_spte(iter.old_spte, iter.level)) | |
805 | continue; | |
806 | ||
807 | new_spte = iter.old_spte & ~PT_WRITABLE_MASK; | |
808 | ||
809 | tdp_mmu_set_spte_no_dirty_log(kvm, &iter, new_spte); | |
810 | spte_set = true; | |
811 | ||
812 | tdp_mmu_iter_cond_resched(kvm, &iter); | |
813 | } | |
814 | return spte_set; | |
815 | } | |
816 | ||
817 | /* | |
818 | * Remove write access from all the SPTEs mapping GFNs in the memslot. Will | |
819 | * only affect leaf SPTEs down to min_level. | |
820 | * Returns true if an SPTE has been changed and the TLBs need to be flushed. | |
821 | */ | |
822 | bool kvm_tdp_mmu_wrprot_slot(struct kvm *kvm, struct kvm_memory_slot *slot, | |
823 | int min_level) | |
824 | { | |
825 | struct kvm_mmu_page *root; | |
826 | int root_as_id; | |
827 | bool spte_set = false; | |
828 | ||
829 | for_each_tdp_mmu_root(kvm, root) { | |
830 | root_as_id = kvm_mmu_page_as_id(root); | |
831 | if (root_as_id != slot->as_id) | |
832 | continue; | |
833 | ||
834 | /* | |
835 | * Take a reference on the root so that it cannot be freed if | |
836 | * this thread releases the MMU lock and yields in this loop. | |
837 | */ | |
838 | kvm_mmu_get_root(kvm, root); | |
839 | ||
840 | spte_set |= wrprot_gfn_range(kvm, root, slot->base_gfn, | |
841 | slot->base_gfn + slot->npages, min_level); | |
842 | ||
843 | kvm_mmu_put_root(kvm, root); | |
844 | } | |
845 | ||
846 | return spte_set; | |
847 | } | |
848 | ||
849 | /* | |
850 | * Clear the dirty status of all the SPTEs mapping GFNs in the memslot. If | |
851 | * AD bits are enabled, this will involve clearing the dirty bit on each SPTE. | |
852 | * If AD bits are not enabled, this will require clearing the writable bit on | |
853 | * each SPTE. Returns true if an SPTE has been changed and the TLBs need to | |
854 | * be flushed. | |
855 | */ | |
856 | static bool clear_dirty_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, | |
857 | gfn_t start, gfn_t end) | |
858 | { | |
859 | struct tdp_iter iter; | |
860 | u64 new_spte; | |
861 | bool spte_set = false; | |
862 | ||
863 | tdp_root_for_each_leaf_pte(iter, root, start, end) { | |
864 | if (spte_ad_need_write_protect(iter.old_spte)) { | |
865 | if (is_writable_pte(iter.old_spte)) | |
866 | new_spte = iter.old_spte & ~PT_WRITABLE_MASK; | |
867 | else | |
868 | continue; | |
869 | } else { | |
870 | if (iter.old_spte & shadow_dirty_mask) | |
871 | new_spte = iter.old_spte & ~shadow_dirty_mask; | |
872 | else | |
873 | continue; | |
874 | } | |
875 | ||
876 | tdp_mmu_set_spte_no_dirty_log(kvm, &iter, new_spte); | |
877 | spte_set = true; | |
878 | ||
879 | tdp_mmu_iter_cond_resched(kvm, &iter); | |
880 | } | |
881 | return spte_set; | |
882 | } | |
883 | ||
884 | /* | |
885 | * Clear the dirty status of all the SPTEs mapping GFNs in the memslot. If | |
886 | * AD bits are enabled, this will involve clearing the dirty bit on each SPTE. | |
887 | * If AD bits are not enabled, this will require clearing the writable bit on | |
888 | * each SPTE. Returns true if an SPTE has been changed and the TLBs need to | |
889 | * be flushed. | |
890 | */ | |
891 | bool kvm_tdp_mmu_clear_dirty_slot(struct kvm *kvm, struct kvm_memory_slot *slot) | |
892 | { | |
893 | struct kvm_mmu_page *root; | |
894 | int root_as_id; | |
895 | bool spte_set = false; | |
896 | ||
897 | for_each_tdp_mmu_root(kvm, root) { | |
898 | root_as_id = kvm_mmu_page_as_id(root); | |
899 | if (root_as_id != slot->as_id) | |
900 | continue; | |
901 | ||
902 | /* | |
903 | * Take a reference on the root so that it cannot be freed if | |
904 | * this thread releases the MMU lock and yields in this loop. | |
905 | */ | |
906 | kvm_mmu_get_root(kvm, root); | |
907 | ||
908 | spte_set |= clear_dirty_gfn_range(kvm, root, slot->base_gfn, | |
909 | slot->base_gfn + slot->npages); | |
910 | ||
911 | kvm_mmu_put_root(kvm, root); | |
912 | } | |
913 | ||
914 | return spte_set; | |
915 | } | |
916 | ||
917 | /* | |
918 | * Clears the dirty status of all the 4k SPTEs mapping GFNs for which a bit is | |
919 | * set in mask, starting at gfn. The given memslot is expected to contain all | |
920 | * the GFNs represented by set bits in the mask. If AD bits are enabled, | |
921 | * clearing the dirty status will involve clearing the dirty bit on each SPTE | |
922 | * or, if AD bits are not enabled, clearing the writable bit on each SPTE. | |
923 | */ | |
924 | static void clear_dirty_pt_masked(struct kvm *kvm, struct kvm_mmu_page *root, | |
925 | gfn_t gfn, unsigned long mask, bool wrprot) | |
926 | { | |
927 | struct tdp_iter iter; | |
928 | u64 new_spte; | |
929 | ||
930 | tdp_root_for_each_leaf_pte(iter, root, gfn + __ffs(mask), | |
931 | gfn + BITS_PER_LONG) { | |
932 | if (!mask) | |
933 | break; | |
934 | ||
935 | if (iter.level > PG_LEVEL_4K || | |
936 | !(mask & (1UL << (iter.gfn - gfn)))) | |
937 | continue; | |
938 | ||
939 | if (wrprot || spte_ad_need_write_protect(iter.old_spte)) { | |
940 | if (is_writable_pte(iter.old_spte)) | |
941 | new_spte = iter.old_spte & ~PT_WRITABLE_MASK; | |
942 | else | |
943 | continue; | |
944 | } else { | |
945 | if (iter.old_spte & shadow_dirty_mask) | |
946 | new_spte = iter.old_spte & ~shadow_dirty_mask; | |
947 | else | |
948 | continue; | |
949 | } | |
950 | ||
951 | tdp_mmu_set_spte_no_dirty_log(kvm, &iter, new_spte); | |
952 | ||
953 | mask &= ~(1UL << (iter.gfn - gfn)); | |
954 | } | |
955 | } | |
956 | ||
957 | /* | |
958 | * Clears the dirty status of all the 4k SPTEs mapping GFNs for which a bit is | |
959 | * set in mask, starting at gfn. The given memslot is expected to contain all | |
960 | * the GFNs represented by set bits in the mask. If AD bits are enabled, | |
961 | * clearing the dirty status will involve clearing the dirty bit on each SPTE | |
962 | * or, if AD bits are not enabled, clearing the writable bit on each SPTE. | |
963 | */ | |
964 | void kvm_tdp_mmu_clear_dirty_pt_masked(struct kvm *kvm, | |
965 | struct kvm_memory_slot *slot, | |
966 | gfn_t gfn, unsigned long mask, | |
967 | bool wrprot) | |
968 | { | |
969 | struct kvm_mmu_page *root; | |
970 | int root_as_id; | |
971 | ||
972 | lockdep_assert_held(&kvm->mmu_lock); | |
973 | for_each_tdp_mmu_root(kvm, root) { | |
974 | root_as_id = kvm_mmu_page_as_id(root); | |
975 | if (root_as_id != slot->as_id) | |
976 | continue; | |
977 | ||
978 | clear_dirty_pt_masked(kvm, root, gfn, mask, wrprot); | |
979 | } | |
980 | } | |
981 | ||
982 | /* | |
983 | * Set the dirty status of all the SPTEs mapping GFNs in the memslot. This is | |
984 | * only used for PML, and so will involve setting the dirty bit on each SPTE. | |
985 | * Returns true if an SPTE has been changed and the TLBs need to be flushed. | |
986 | */ | |
987 | static bool set_dirty_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, | |
988 | gfn_t start, gfn_t end) | |
989 | { | |
990 | struct tdp_iter iter; | |
991 | u64 new_spte; | |
992 | bool spte_set = false; | |
993 | ||
994 | tdp_root_for_each_pte(iter, root, start, end) { | |
995 | if (!is_shadow_present_pte(iter.old_spte)) | |
996 | continue; | |
997 | ||
998 | new_spte = iter.old_spte | shadow_dirty_mask; | |
999 | ||
1000 | tdp_mmu_set_spte(kvm, &iter, new_spte); | |
1001 | spte_set = true; | |
1002 | ||
1003 | tdp_mmu_iter_cond_resched(kvm, &iter); | |
1004 | } | |
1005 | ||
1006 | return spte_set; | |
1007 | } | |
1008 | ||
1009 | /* | |
1010 | * Set the dirty status of all the SPTEs mapping GFNs in the memslot. This is | |
1011 | * only used for PML, and so will involve setting the dirty bit on each SPTE. | |
1012 | * Returns true if an SPTE has been changed and the TLBs need to be flushed. | |
1013 | */ | |
1014 | bool kvm_tdp_mmu_slot_set_dirty(struct kvm *kvm, struct kvm_memory_slot *slot) | |
1015 | { | |
1016 | struct kvm_mmu_page *root; | |
1017 | int root_as_id; | |
1018 | bool spte_set = false; | |
1019 | ||
1020 | for_each_tdp_mmu_root(kvm, root) { | |
1021 | root_as_id = kvm_mmu_page_as_id(root); | |
1022 | if (root_as_id != slot->as_id) | |
1023 | continue; | |
1024 | ||
1025 | /* | |
1026 | * Take a reference on the root so that it cannot be freed if | |
1027 | * this thread releases the MMU lock and yields in this loop. | |
1028 | */ | |
1029 | kvm_mmu_get_root(kvm, root); | |
1030 | ||
1031 | spte_set |= set_dirty_gfn_range(kvm, root, slot->base_gfn, | |
1032 | slot->base_gfn + slot->npages); | |
1033 | ||
1034 | kvm_mmu_put_root(kvm, root); | |
1035 | } | |
1036 | return spte_set; | |
1037 | } | |
1038 | ||
14881998 BG |
1039 | /* |
1040 | * Clear non-leaf entries (and free associated page tables) which could | |
1041 | * be replaced by large mappings, for GFNs within the slot. | |
1042 | */ | |
1043 | static void zap_collapsible_spte_range(struct kvm *kvm, | |
1044 | struct kvm_mmu_page *root, | |
1045 | gfn_t start, gfn_t end) | |
1046 | { | |
1047 | struct tdp_iter iter; | |
1048 | kvm_pfn_t pfn; | |
1049 | bool spte_set = false; | |
1050 | ||
1051 | tdp_root_for_each_pte(iter, root, start, end) { | |
1052 | if (!is_shadow_present_pte(iter.old_spte) || | |
1053 | is_last_spte(iter.old_spte, iter.level)) | |
1054 | continue; | |
1055 | ||
1056 | pfn = spte_to_pfn(iter.old_spte); | |
1057 | if (kvm_is_reserved_pfn(pfn) || | |
1058 | !PageTransCompoundMap(pfn_to_page(pfn))) | |
1059 | continue; | |
1060 | ||
1061 | tdp_mmu_set_spte(kvm, &iter, 0); | |
1062 | ||
1063 | spte_set = tdp_mmu_iter_flush_cond_resched(kvm, &iter); | |
1064 | } | |
1065 | ||
1066 | if (spte_set) | |
1067 | kvm_flush_remote_tlbs(kvm); | |
1068 | } | |
1069 | ||
1070 | /* | |
1071 | * Clear non-leaf entries (and free associated page tables) which could | |
1072 | * be replaced by large mappings, for GFNs within the slot. | |
1073 | */ | |
1074 | void kvm_tdp_mmu_zap_collapsible_sptes(struct kvm *kvm, | |
1075 | const struct kvm_memory_slot *slot) | |
1076 | { | |
1077 | struct kvm_mmu_page *root; | |
1078 | int root_as_id; | |
1079 | ||
1080 | for_each_tdp_mmu_root(kvm, root) { | |
1081 | root_as_id = kvm_mmu_page_as_id(root); | |
1082 | if (root_as_id != slot->as_id) | |
1083 | continue; | |
1084 | ||
1085 | /* | |
1086 | * Take a reference on the root so that it cannot be freed if | |
1087 | * this thread releases the MMU lock and yields in this loop. | |
1088 | */ | |
1089 | kvm_mmu_get_root(kvm, root); | |
1090 | ||
1091 | zap_collapsible_spte_range(kvm, root, slot->base_gfn, | |
1092 | slot->base_gfn + slot->npages); | |
1093 | ||
1094 | kvm_mmu_put_root(kvm, root); | |
1095 | } | |
1096 | } | |
46044f72 BG |
1097 | |
1098 | /* | |
1099 | * Removes write access on the last level SPTE mapping this GFN and unsets the | |
1100 | * SPTE_MMU_WRITABLE bit to ensure future writes continue to be intercepted. | |
1101 | * Returns true if an SPTE was set and a TLB flush is needed. | |
1102 | */ | |
1103 | static bool write_protect_gfn(struct kvm *kvm, struct kvm_mmu_page *root, | |
1104 | gfn_t gfn) | |
1105 | { | |
1106 | struct tdp_iter iter; | |
1107 | u64 new_spte; | |
1108 | bool spte_set = false; | |
1109 | ||
1110 | tdp_root_for_each_leaf_pte(iter, root, gfn, gfn + 1) { | |
1111 | if (!is_writable_pte(iter.old_spte)) | |
1112 | break; | |
1113 | ||
1114 | new_spte = iter.old_spte & | |
1115 | ~(PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE); | |
1116 | ||
1117 | tdp_mmu_set_spte(kvm, &iter, new_spte); | |
1118 | spte_set = true; | |
1119 | } | |
1120 | ||
1121 | return spte_set; | |
1122 | } | |
1123 | ||
1124 | /* | |
1125 | * Removes write access on the last level SPTE mapping this GFN and unsets the | |
1126 | * SPTE_MMU_WRITABLE bit to ensure future writes continue to be intercepted. | |
1127 | * Returns true if an SPTE was set and a TLB flush is needed. | |
1128 | */ | |
1129 | bool kvm_tdp_mmu_write_protect_gfn(struct kvm *kvm, | |
1130 | struct kvm_memory_slot *slot, gfn_t gfn) | |
1131 | { | |
1132 | struct kvm_mmu_page *root; | |
1133 | int root_as_id; | |
1134 | bool spte_set = false; | |
1135 | ||
1136 | lockdep_assert_held(&kvm->mmu_lock); | |
1137 | for_each_tdp_mmu_root(kvm, root) { | |
1138 | root_as_id = kvm_mmu_page_as_id(root); | |
1139 | if (root_as_id != slot->as_id) | |
1140 | continue; | |
1141 | ||
1142 | spte_set |= write_protect_gfn(kvm, root, gfn); | |
1143 | } | |
1144 | return spte_set; | |
1145 | } | |
1146 | ||
95fb5b02 BG |
1147 | /* |
1148 | * Return the level of the lowest level SPTE added to sptes. | |
1149 | * That SPTE may be non-present. | |
1150 | */ | |
1151 | int kvm_tdp_mmu_get_walk(struct kvm_vcpu *vcpu, u64 addr, u64 *sptes) | |
1152 | { | |
1153 | struct tdp_iter iter; | |
1154 | struct kvm_mmu *mmu = vcpu->arch.mmu; | |
1155 | int leaf = vcpu->arch.mmu->shadow_root_level; | |
1156 | gfn_t gfn = addr >> PAGE_SHIFT; | |
1157 | ||
1158 | tdp_mmu_for_each_pte(iter, mmu, gfn, gfn + 1) { | |
1159 | leaf = iter.level; | |
1160 | sptes[leaf - 1] = iter.old_spte; | |
1161 | } | |
1162 | ||
1163 | return leaf; | |
1164 | } |