Commit | Line | Data |
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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 | |
9a77daac | 10 | #include <asm/cmpxchg.h> |
33dd3574 BG |
11 | #include <trace/events/kvm.h> |
12 | ||
fe5db27d | 13 | static bool __read_mostly tdp_mmu_enabled = false; |
95fb5b02 | 14 | module_param_named(tdp_mmu, tdp_mmu_enabled, bool, 0644); |
fe5db27d BG |
15 | |
16 | /* Initializes the TDP MMU for the VM, if enabled. */ | |
17 | void kvm_mmu_init_tdp_mmu(struct kvm *kvm) | |
18 | { | |
897218ff | 19 | if (!tdp_enabled || !READ_ONCE(tdp_mmu_enabled)) |
fe5db27d BG |
20 | return; |
21 | ||
22 | /* This should not be changed for the lifetime of the VM. */ | |
23 | kvm->arch.tdp_mmu_enabled = true; | |
02c00b3a BG |
24 | |
25 | INIT_LIST_HEAD(&kvm->arch.tdp_mmu_roots); | |
9a77daac | 26 | spin_lock_init(&kvm->arch.tdp_mmu_pages_lock); |
89c0fd49 | 27 | INIT_LIST_HEAD(&kvm->arch.tdp_mmu_pages); |
fe5db27d BG |
28 | } |
29 | ||
6103bc07 BG |
30 | static __always_inline void kvm_lockdep_assert_mmu_lock_held(struct kvm *kvm, |
31 | bool shared) | |
32 | { | |
33 | if (shared) | |
34 | lockdep_assert_held_read(&kvm->mmu_lock); | |
35 | else | |
36 | lockdep_assert_held_write(&kvm->mmu_lock); | |
37 | } | |
38 | ||
fe5db27d BG |
39 | void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm) |
40 | { | |
41 | if (!kvm->arch.tdp_mmu_enabled) | |
42 | return; | |
02c00b3a BG |
43 | |
44 | WARN_ON(!list_empty(&kvm->arch.tdp_mmu_roots)); | |
7cca2d0b BG |
45 | |
46 | /* | |
47 | * Ensure that all the outstanding RCU callbacks to free shadow pages | |
48 | * can run before the VM is torn down. | |
49 | */ | |
50 | rcu_barrier(); | |
02c00b3a BG |
51 | } |
52 | ||
2bdb3d84 | 53 | static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, |
6103bc07 BG |
54 | gfn_t start, gfn_t end, bool can_yield, bool flush, |
55 | bool shared); | |
2bdb3d84 BG |
56 | |
57 | static void tdp_mmu_free_sp(struct kvm_mmu_page *sp) | |
a889ea54 | 58 | { |
2bdb3d84 BG |
59 | free_page((unsigned long)sp->spt); |
60 | kmem_cache_free(mmu_page_header_cache, sp); | |
a889ea54 BG |
61 | } |
62 | ||
c0e64238 BG |
63 | /* |
64 | * This is called through call_rcu in order to free TDP page table memory | |
65 | * safely with respect to other kernel threads that may be operating on | |
66 | * the memory. | |
67 | * By only accessing TDP MMU page table memory in an RCU read critical | |
68 | * section, and freeing it after a grace period, lockless access to that | |
69 | * memory won't use it after it is freed. | |
70 | */ | |
71 | static void tdp_mmu_free_sp_rcu_callback(struct rcu_head *head) | |
a889ea54 | 72 | { |
c0e64238 BG |
73 | struct kvm_mmu_page *sp = container_of(head, struct kvm_mmu_page, |
74 | rcu_head); | |
a889ea54 | 75 | |
c0e64238 BG |
76 | tdp_mmu_free_sp(sp); |
77 | } | |
a889ea54 | 78 | |
6103bc07 BG |
79 | void kvm_tdp_mmu_put_root(struct kvm *kvm, struct kvm_mmu_page *root, |
80 | bool shared) | |
2bdb3d84 BG |
81 | { |
82 | gfn_t max_gfn = 1ULL << (shadow_phys_bits - PAGE_SHIFT); | |
83 | ||
6103bc07 | 84 | kvm_lockdep_assert_mmu_lock_held(kvm, shared); |
a889ea54 | 85 | |
11cccf5c | 86 | if (!refcount_dec_and_test(&root->tdp_mmu_root_count)) |
2bdb3d84 BG |
87 | return; |
88 | ||
89 | WARN_ON(!root->tdp_mmu_page); | |
90 | ||
c0e64238 BG |
91 | spin_lock(&kvm->arch.tdp_mmu_pages_lock); |
92 | list_del_rcu(&root->link); | |
93 | spin_unlock(&kvm->arch.tdp_mmu_pages_lock); | |
2bdb3d84 | 94 | |
6103bc07 | 95 | zap_gfn_range(kvm, root, 0, max_gfn, false, false, shared); |
2bdb3d84 | 96 | |
c0e64238 | 97 | call_rcu(&root->rcu_head, tdp_mmu_free_sp_rcu_callback); |
a889ea54 BG |
98 | } |
99 | ||
cfc10997 BG |
100 | /* |
101 | * Finds the next valid root after root (or the first valid root if root | |
102 | * is NULL), takes a reference on it, and returns that next root. If root | |
103 | * is not NULL, this thread should have already taken a reference on it, and | |
104 | * that reference will be dropped. If no valid root is found, this | |
105 | * function will return NULL. | |
106 | */ | |
107 | static struct kvm_mmu_page *tdp_mmu_next_root(struct kvm *kvm, | |
6103bc07 BG |
108 | struct kvm_mmu_page *prev_root, |
109 | bool shared) | |
a889ea54 BG |
110 | { |
111 | struct kvm_mmu_page *next_root; | |
112 | ||
c0e64238 BG |
113 | rcu_read_lock(); |
114 | ||
cfc10997 | 115 | if (prev_root) |
c0e64238 BG |
116 | next_root = list_next_or_null_rcu(&kvm->arch.tdp_mmu_roots, |
117 | &prev_root->link, | |
118 | typeof(*prev_root), link); | |
cfc10997 | 119 | else |
c0e64238 BG |
120 | next_root = list_first_or_null_rcu(&kvm->arch.tdp_mmu_roots, |
121 | typeof(*next_root), link); | |
a889ea54 | 122 | |
c0e64238 BG |
123 | while (next_root && !kvm_tdp_mmu_get_root(kvm, next_root)) |
124 | next_root = list_next_or_null_rcu(&kvm->arch.tdp_mmu_roots, | |
125 | &next_root->link, typeof(*next_root), link); | |
fb101293 | 126 | |
c0e64238 | 127 | rcu_read_unlock(); |
a889ea54 | 128 | |
cfc10997 | 129 | if (prev_root) |
6103bc07 | 130 | kvm_tdp_mmu_put_root(kvm, prev_root, shared); |
a889ea54 | 131 | |
a889ea54 BG |
132 | return next_root; |
133 | } | |
134 | ||
135 | /* | |
136 | * Note: this iterator gets and puts references to the roots it iterates over. | |
137 | * This makes it safe to release the MMU lock and yield within the loop, but | |
138 | * if exiting the loop early, the caller must drop the reference to the most | |
139 | * recent root. (Unless keeping a live reference is desirable.) | |
6103bc07 BG |
140 | * |
141 | * If shared is set, this function is operating under the MMU lock in read | |
142 | * mode. In the unlikely event that this thread must free a root, the lock | |
143 | * will be temporarily dropped and reacquired in write mode. | |
a889ea54 | 144 | */ |
6103bc07 BG |
145 | #define for_each_tdp_mmu_root_yield_safe(_kvm, _root, _as_id, _shared) \ |
146 | for (_root = tdp_mmu_next_root(_kvm, NULL, _shared); \ | |
147 | _root; \ | |
148 | _root = tdp_mmu_next_root(_kvm, _root, _shared)) \ | |
149 | if (kvm_mmu_page_as_id(_root) != _as_id) { \ | |
a3f15bda | 150 | } else |
a889ea54 | 151 | |
c0e64238 BG |
152 | #define for_each_tdp_mmu_root(_kvm, _root, _as_id) \ |
153 | list_for_each_entry_rcu(_root, &_kvm->arch.tdp_mmu_roots, link, \ | |
154 | lockdep_is_held_type(&kvm->mmu_lock, 0) || \ | |
155 | lockdep_is_held(&kvm->arch.tdp_mmu_pages_lock)) \ | |
a3f15bda SC |
156 | if (kvm_mmu_page_as_id(_root) != _as_id) { \ |
157 | } else | |
02c00b3a BG |
158 | |
159 | static union kvm_mmu_page_role page_role_for_level(struct kvm_vcpu *vcpu, | |
160 | int level) | |
161 | { | |
162 | union kvm_mmu_page_role role; | |
163 | ||
164 | role = vcpu->arch.mmu->mmu_role.base; | |
165 | role.level = level; | |
166 | role.direct = true; | |
167 | role.gpte_is_8_bytes = true; | |
168 | role.access = ACC_ALL; | |
169 | ||
170 | return role; | |
171 | } | |
172 | ||
173 | static struct kvm_mmu_page *alloc_tdp_mmu_page(struct kvm_vcpu *vcpu, gfn_t gfn, | |
174 | int level) | |
175 | { | |
176 | struct kvm_mmu_page *sp; | |
177 | ||
178 | sp = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache); | |
179 | sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache); | |
180 | set_page_private(virt_to_page(sp->spt), (unsigned long)sp); | |
181 | ||
182 | sp->role.word = page_role_for_level(vcpu, level).word; | |
183 | sp->gfn = gfn; | |
184 | sp->tdp_mmu_page = true; | |
185 | ||
33dd3574 BG |
186 | trace_kvm_mmu_get_page(sp, true); |
187 | ||
02c00b3a BG |
188 | return sp; |
189 | } | |
190 | ||
6e6ec584 | 191 | hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu) |
02c00b3a BG |
192 | { |
193 | union kvm_mmu_page_role role; | |
194 | struct kvm *kvm = vcpu->kvm; | |
195 | struct kvm_mmu_page *root; | |
196 | ||
6e6ec584 | 197 | lockdep_assert_held_write(&kvm->mmu_lock); |
02c00b3a | 198 | |
6e6ec584 | 199 | role = page_role_for_level(vcpu, vcpu->arch.mmu->shadow_root_level); |
02c00b3a BG |
200 | |
201 | /* Check for an existing root before allocating a new one. */ | |
a3f15bda | 202 | for_each_tdp_mmu_root(kvm, root, kvm_mmu_role_as_id(role)) { |
fb101293 BG |
203 | if (root->role.word == role.word && |
204 | kvm_tdp_mmu_get_root(kvm, root)) | |
6e6ec584 | 205 | goto out; |
02c00b3a BG |
206 | } |
207 | ||
208 | root = alloc_tdp_mmu_page(vcpu, 0, vcpu->arch.mmu->shadow_root_level); | |
11cccf5c | 209 | refcount_set(&root->tdp_mmu_root_count, 1); |
02c00b3a | 210 | |
c0e64238 BG |
211 | spin_lock(&kvm->arch.tdp_mmu_pages_lock); |
212 | list_add_rcu(&root->link, &kvm->arch.tdp_mmu_roots); | |
213 | spin_unlock(&kvm->arch.tdp_mmu_pages_lock); | |
02c00b3a | 214 | |
6e6ec584 | 215 | out: |
02c00b3a | 216 | return __pa(root->spt); |
fe5db27d | 217 | } |
2f2fad08 BG |
218 | |
219 | static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn, | |
9a77daac BG |
220 | u64 old_spte, u64 new_spte, int level, |
221 | bool shared); | |
2f2fad08 | 222 | |
f8e14497 BG |
223 | static void handle_changed_spte_acc_track(u64 old_spte, u64 new_spte, int level) |
224 | { | |
f8e14497 BG |
225 | if (!is_shadow_present_pte(old_spte) || !is_last_spte(old_spte, level)) |
226 | return; | |
227 | ||
228 | if (is_accessed_spte(old_spte) && | |
64bb2769 SC |
229 | (!is_shadow_present_pte(new_spte) || !is_accessed_spte(new_spte) || |
230 | spte_to_pfn(old_spte) != spte_to_pfn(new_spte))) | |
f8e14497 BG |
231 | kvm_set_pfn_accessed(spte_to_pfn(old_spte)); |
232 | } | |
233 | ||
a6a0b05d BG |
234 | static void handle_changed_spte_dirty_log(struct kvm *kvm, int as_id, gfn_t gfn, |
235 | u64 old_spte, u64 new_spte, int level) | |
236 | { | |
237 | bool pfn_changed; | |
238 | struct kvm_memory_slot *slot; | |
239 | ||
240 | if (level > PG_LEVEL_4K) | |
241 | return; | |
242 | ||
243 | pfn_changed = spte_to_pfn(old_spte) != spte_to_pfn(new_spte); | |
244 | ||
245 | if ((!is_writable_pte(old_spte) || pfn_changed) && | |
246 | is_writable_pte(new_spte)) { | |
247 | slot = __gfn_to_memslot(__kvm_memslots(kvm, as_id), gfn); | |
fb04a1ed | 248 | mark_page_dirty_in_slot(kvm, slot, gfn); |
a6a0b05d BG |
249 | } |
250 | } | |
251 | ||
a9442f59 BG |
252 | /** |
253 | * tdp_mmu_link_page - Add a new page to the list of pages used by the TDP MMU | |
254 | * | |
255 | * @kvm: kvm instance | |
256 | * @sp: the new page | |
9a77daac BG |
257 | * @shared: This operation may not be running under the exclusive use of |
258 | * the MMU lock and the operation must synchronize with other | |
259 | * threads that might be adding or removing pages. | |
a9442f59 BG |
260 | * @account_nx: This page replaces a NX large page and should be marked for |
261 | * eventual reclaim. | |
262 | */ | |
263 | static void tdp_mmu_link_page(struct kvm *kvm, struct kvm_mmu_page *sp, | |
9a77daac | 264 | bool shared, bool account_nx) |
a9442f59 | 265 | { |
9a77daac BG |
266 | if (shared) |
267 | spin_lock(&kvm->arch.tdp_mmu_pages_lock); | |
268 | else | |
269 | lockdep_assert_held_write(&kvm->mmu_lock); | |
a9442f59 BG |
270 | |
271 | list_add(&sp->link, &kvm->arch.tdp_mmu_pages); | |
272 | if (account_nx) | |
273 | account_huge_nx_page(kvm, sp); | |
9a77daac BG |
274 | |
275 | if (shared) | |
276 | spin_unlock(&kvm->arch.tdp_mmu_pages_lock); | |
a9442f59 BG |
277 | } |
278 | ||
279 | /** | |
280 | * tdp_mmu_unlink_page - Remove page from the list of pages used by the TDP MMU | |
281 | * | |
282 | * @kvm: kvm instance | |
283 | * @sp: the page to be removed | |
9a77daac BG |
284 | * @shared: This operation may not be running under the exclusive use of |
285 | * the MMU lock and the operation must synchronize with other | |
286 | * threads that might be adding or removing pages. | |
a9442f59 | 287 | */ |
9a77daac BG |
288 | static void tdp_mmu_unlink_page(struct kvm *kvm, struct kvm_mmu_page *sp, |
289 | bool shared) | |
a9442f59 | 290 | { |
9a77daac BG |
291 | if (shared) |
292 | spin_lock(&kvm->arch.tdp_mmu_pages_lock); | |
293 | else | |
294 | lockdep_assert_held_write(&kvm->mmu_lock); | |
a9442f59 BG |
295 | |
296 | list_del(&sp->link); | |
297 | if (sp->lpage_disallowed) | |
298 | unaccount_huge_nx_page(kvm, sp); | |
9a77daac BG |
299 | |
300 | if (shared) | |
301 | spin_unlock(&kvm->arch.tdp_mmu_pages_lock); | |
a9442f59 BG |
302 | } |
303 | ||
a066e61f BG |
304 | /** |
305 | * handle_removed_tdp_mmu_page - handle a pt removed from the TDP structure | |
306 | * | |
307 | * @kvm: kvm instance | |
308 | * @pt: the page removed from the paging structure | |
9a77daac BG |
309 | * @shared: This operation may not be running under the exclusive use |
310 | * of the MMU lock and the operation must synchronize with other | |
311 | * threads that might be modifying SPTEs. | |
a066e61f BG |
312 | * |
313 | * Given a page table that has been removed from the TDP paging structure, | |
314 | * iterates through the page table to clear SPTEs and free child page tables. | |
70fb3e41 BG |
315 | * |
316 | * Note that pt is passed in as a tdp_ptep_t, but it does not need RCU | |
317 | * protection. Since this thread removed it from the paging structure, | |
318 | * this thread will be responsible for ensuring the page is freed. Hence the | |
319 | * early rcu_dereferences in the function. | |
a066e61f | 320 | */ |
70fb3e41 | 321 | static void handle_removed_tdp_mmu_page(struct kvm *kvm, tdp_ptep_t pt, |
9a77daac | 322 | bool shared) |
a066e61f | 323 | { |
70fb3e41 | 324 | struct kvm_mmu_page *sp = sptep_to_sp(rcu_dereference(pt)); |
a066e61f | 325 | int level = sp->role.level; |
e25f0e0c | 326 | gfn_t base_gfn = sp->gfn; |
a066e61f | 327 | u64 old_child_spte; |
9a77daac | 328 | u64 *sptep; |
e25f0e0c | 329 | gfn_t gfn; |
a066e61f BG |
330 | int i; |
331 | ||
332 | trace_kvm_mmu_prepare_zap_page(sp); | |
333 | ||
9a77daac | 334 | tdp_mmu_unlink_page(kvm, sp, shared); |
a066e61f BG |
335 | |
336 | for (i = 0; i < PT64_ENT_PER_PAGE; i++) { | |
70fb3e41 | 337 | sptep = rcu_dereference(pt) + i; |
e25f0e0c | 338 | gfn = base_gfn + (i * KVM_PAGES_PER_HPAGE(level - 1)); |
9a77daac BG |
339 | |
340 | if (shared) { | |
e25f0e0c BG |
341 | /* |
342 | * Set the SPTE to a nonpresent value that other | |
343 | * threads will not overwrite. If the SPTE was | |
344 | * already marked as removed then another thread | |
345 | * handling a page fault could overwrite it, so | |
346 | * set the SPTE until it is set from some other | |
347 | * value to the removed SPTE value. | |
348 | */ | |
349 | for (;;) { | |
350 | old_child_spte = xchg(sptep, REMOVED_SPTE); | |
351 | if (!is_removed_spte(old_child_spte)) | |
352 | break; | |
353 | cpu_relax(); | |
354 | } | |
9a77daac | 355 | } else { |
8df9f1af SC |
356 | /* |
357 | * If the SPTE is not MMU-present, there is no backing | |
358 | * page associated with the SPTE and so no side effects | |
359 | * that need to be recorded, and exclusive ownership of | |
360 | * mmu_lock ensures the SPTE can't be made present. | |
361 | * Note, zapping MMIO SPTEs is also unnecessary as they | |
362 | * are guarded by the memslots generation, not by being | |
363 | * unreachable. | |
364 | */ | |
9a77daac | 365 | old_child_spte = READ_ONCE(*sptep); |
8df9f1af SC |
366 | if (!is_shadow_present_pte(old_child_spte)) |
367 | continue; | |
e25f0e0c BG |
368 | |
369 | /* | |
370 | * Marking the SPTE as a removed SPTE is not | |
371 | * strictly necessary here as the MMU lock will | |
372 | * stop other threads from concurrently modifying | |
373 | * this SPTE. Using the removed SPTE value keeps | |
374 | * the two branches consistent and simplifies | |
375 | * the function. | |
376 | */ | |
377 | WRITE_ONCE(*sptep, REMOVED_SPTE); | |
9a77daac | 378 | } |
e25f0e0c BG |
379 | handle_changed_spte(kvm, kvm_mmu_page_as_id(sp), gfn, |
380 | old_child_spte, REMOVED_SPTE, level - 1, | |
381 | shared); | |
a066e61f BG |
382 | } |
383 | ||
384 | kvm_flush_remote_tlbs_with_address(kvm, gfn, | |
385 | KVM_PAGES_PER_HPAGE(level)); | |
386 | ||
7cca2d0b | 387 | call_rcu(&sp->rcu_head, tdp_mmu_free_sp_rcu_callback); |
a066e61f BG |
388 | } |
389 | ||
2f2fad08 BG |
390 | /** |
391 | * handle_changed_spte - handle bookkeeping associated with an SPTE change | |
392 | * @kvm: kvm instance | |
393 | * @as_id: the address space of the paging structure the SPTE was a part of | |
394 | * @gfn: the base GFN that was mapped by the SPTE | |
395 | * @old_spte: The value of the SPTE before the change | |
396 | * @new_spte: The value of the SPTE after the change | |
397 | * @level: the level of the PT the SPTE is part of in the paging structure | |
9a77daac BG |
398 | * @shared: This operation may not be running under the exclusive use of |
399 | * the MMU lock and the operation must synchronize with other | |
400 | * threads that might be modifying SPTEs. | |
2f2fad08 BG |
401 | * |
402 | * Handle bookkeeping that might result from the modification of a SPTE. | |
403 | * This function must be called for all TDP SPTE modifications. | |
404 | */ | |
405 | static void __handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn, | |
9a77daac BG |
406 | u64 old_spte, u64 new_spte, int level, |
407 | bool shared) | |
2f2fad08 BG |
408 | { |
409 | bool was_present = is_shadow_present_pte(old_spte); | |
410 | bool is_present = is_shadow_present_pte(new_spte); | |
411 | bool was_leaf = was_present && is_last_spte(old_spte, level); | |
412 | bool is_leaf = is_present && is_last_spte(new_spte, level); | |
413 | bool pfn_changed = spte_to_pfn(old_spte) != spte_to_pfn(new_spte); | |
2f2fad08 BG |
414 | |
415 | WARN_ON(level > PT64_ROOT_MAX_LEVEL); | |
416 | WARN_ON(level < PG_LEVEL_4K); | |
764388ce | 417 | WARN_ON(gfn & (KVM_PAGES_PER_HPAGE(level) - 1)); |
2f2fad08 BG |
418 | |
419 | /* | |
420 | * If this warning were to trigger it would indicate that there was a | |
421 | * missing MMU notifier or a race with some notifier handler. | |
422 | * A present, leaf SPTE should never be directly replaced with another | |
d9f6e12f | 423 | * present leaf SPTE pointing to a different PFN. A notifier handler |
2f2fad08 BG |
424 | * should be zapping the SPTE before the main MM's page table is |
425 | * changed, or the SPTE should be zeroed, and the TLBs flushed by the | |
426 | * thread before replacement. | |
427 | */ | |
428 | if (was_leaf && is_leaf && pfn_changed) { | |
429 | pr_err("Invalid SPTE change: cannot replace a present leaf\n" | |
430 | "SPTE with another present leaf SPTE mapping a\n" | |
431 | "different PFN!\n" | |
432 | "as_id: %d gfn: %llx old_spte: %llx new_spte: %llx level: %d", | |
433 | as_id, gfn, old_spte, new_spte, level); | |
434 | ||
435 | /* | |
436 | * Crash the host to prevent error propagation and guest data | |
d9f6e12f | 437 | * corruption. |
2f2fad08 BG |
438 | */ |
439 | BUG(); | |
440 | } | |
441 | ||
442 | if (old_spte == new_spte) | |
443 | return; | |
444 | ||
b9a98c34 BG |
445 | trace_kvm_tdp_mmu_spte_changed(as_id, gfn, level, old_spte, new_spte); |
446 | ||
1699f65c SMSH |
447 | if (is_large_pte(old_spte) != is_large_pte(new_spte)) { |
448 | if (is_large_pte(old_spte)) | |
449 | atomic64_sub(1, (atomic64_t*)&kvm->stat.lpages); | |
450 | else | |
451 | atomic64_add(1, (atomic64_t*)&kvm->stat.lpages); | |
452 | } | |
453 | ||
2f2fad08 BG |
454 | /* |
455 | * The only times a SPTE should be changed from a non-present to | |
456 | * non-present state is when an MMIO entry is installed/modified/ | |
457 | * removed. In that case, there is nothing to do here. | |
458 | */ | |
459 | if (!was_present && !is_present) { | |
460 | /* | |
08f07c80 BG |
461 | * If this change does not involve a MMIO SPTE or removed SPTE, |
462 | * it is unexpected. Log the change, though it should not | |
463 | * impact the guest since both the former and current SPTEs | |
464 | * are nonpresent. | |
2f2fad08 | 465 | */ |
08f07c80 BG |
466 | if (WARN_ON(!is_mmio_spte(old_spte) && |
467 | !is_mmio_spte(new_spte) && | |
468 | !is_removed_spte(new_spte))) | |
2f2fad08 BG |
469 | pr_err("Unexpected SPTE change! Nonpresent SPTEs\n" |
470 | "should not be replaced with another,\n" | |
471 | "different nonpresent SPTE, unless one or both\n" | |
08f07c80 BG |
472 | "are MMIO SPTEs, or the new SPTE is\n" |
473 | "a temporary removed SPTE.\n" | |
2f2fad08 BG |
474 | "as_id: %d gfn: %llx old_spte: %llx new_spte: %llx level: %d", |
475 | as_id, gfn, old_spte, new_spte, level); | |
476 | return; | |
477 | } | |
478 | ||
479 | ||
480 | if (was_leaf && is_dirty_spte(old_spte) && | |
64bb2769 | 481 | (!is_present || !is_dirty_spte(new_spte) || pfn_changed)) |
2f2fad08 BG |
482 | kvm_set_pfn_dirty(spte_to_pfn(old_spte)); |
483 | ||
484 | /* | |
485 | * Recursively handle child PTs if the change removed a subtree from | |
486 | * the paging structure. | |
487 | */ | |
a066e61f BG |
488 | if (was_present && !was_leaf && (pfn_changed || !is_present)) |
489 | handle_removed_tdp_mmu_page(kvm, | |
9a77daac | 490 | spte_to_child_pt(old_spte, level), shared); |
2f2fad08 BG |
491 | } |
492 | ||
493 | static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn, | |
9a77daac BG |
494 | u64 old_spte, u64 new_spte, int level, |
495 | bool shared) | |
2f2fad08 | 496 | { |
9a77daac BG |
497 | __handle_changed_spte(kvm, as_id, gfn, old_spte, new_spte, level, |
498 | shared); | |
f8e14497 | 499 | handle_changed_spte_acc_track(old_spte, new_spte, level); |
a6a0b05d BG |
500 | handle_changed_spte_dirty_log(kvm, as_id, gfn, old_spte, |
501 | new_spte, level); | |
2f2fad08 | 502 | } |
faaf05b0 | 503 | |
9a77daac | 504 | /* |
24ae4cfa BG |
505 | * tdp_mmu_set_spte_atomic_no_dirty_log - Set a TDP MMU SPTE atomically |
506 | * and handle the associated bookkeeping, but do not mark the page dirty | |
507 | * in KVM's dirty bitmaps. | |
9a77daac BG |
508 | * |
509 | * @kvm: kvm instance | |
510 | * @iter: a tdp_iter instance currently on the SPTE that should be set | |
511 | * @new_spte: The value the SPTE should be set to | |
512 | * Returns: true if the SPTE was set, false if it was not. If false is returned, | |
513 | * this function will have no side-effects. | |
514 | */ | |
24ae4cfa BG |
515 | static inline bool tdp_mmu_set_spte_atomic_no_dirty_log(struct kvm *kvm, |
516 | struct tdp_iter *iter, | |
517 | u64 new_spte) | |
9a77daac | 518 | { |
9a77daac BG |
519 | lockdep_assert_held_read(&kvm->mmu_lock); |
520 | ||
08f07c80 BG |
521 | /* |
522 | * Do not change removed SPTEs. Only the thread that froze the SPTE | |
523 | * may modify it. | |
524 | */ | |
7a51393a | 525 | if (is_removed_spte(iter->old_spte)) |
08f07c80 BG |
526 | return false; |
527 | ||
9a77daac BG |
528 | if (cmpxchg64(rcu_dereference(iter->sptep), iter->old_spte, |
529 | new_spte) != iter->old_spte) | |
530 | return false; | |
531 | ||
24ae4cfa BG |
532 | __handle_changed_spte(kvm, iter->as_id, iter->gfn, iter->old_spte, |
533 | new_spte, iter->level, true); | |
534 | handle_changed_spte_acc_track(iter->old_spte, new_spte, iter->level); | |
9a77daac BG |
535 | |
536 | return true; | |
537 | } | |
538 | ||
24ae4cfa BG |
539 | static inline bool tdp_mmu_set_spte_atomic(struct kvm *kvm, |
540 | struct tdp_iter *iter, | |
541 | u64 new_spte) | |
542 | { | |
543 | if (!tdp_mmu_set_spte_atomic_no_dirty_log(kvm, iter, new_spte)) | |
544 | return false; | |
545 | ||
546 | handle_changed_spte_dirty_log(kvm, iter->as_id, iter->gfn, | |
547 | iter->old_spte, new_spte, iter->level); | |
548 | return true; | |
549 | } | |
550 | ||
08f07c80 BG |
551 | static inline bool tdp_mmu_zap_spte_atomic(struct kvm *kvm, |
552 | struct tdp_iter *iter) | |
553 | { | |
554 | /* | |
555 | * Freeze the SPTE by setting it to a special, | |
556 | * non-present value. This will stop other threads from | |
557 | * immediately installing a present entry in its place | |
558 | * before the TLBs are flushed. | |
559 | */ | |
560 | if (!tdp_mmu_set_spte_atomic(kvm, iter, REMOVED_SPTE)) | |
561 | return false; | |
562 | ||
563 | kvm_flush_remote_tlbs_with_address(kvm, iter->gfn, | |
564 | KVM_PAGES_PER_HPAGE(iter->level)); | |
565 | ||
566 | /* | |
567 | * No other thread can overwrite the removed SPTE as they | |
568 | * must either wait on the MMU lock or use | |
d9f6e12f | 569 | * tdp_mmu_set_spte_atomic which will not overwrite the |
08f07c80 BG |
570 | * special removed SPTE value. No bookkeeping is needed |
571 | * here since the SPTE is going from non-present | |
572 | * to non-present. | |
573 | */ | |
14f6fec2 | 574 | WRITE_ONCE(*rcu_dereference(iter->sptep), 0); |
08f07c80 BG |
575 | |
576 | return true; | |
577 | } | |
578 | ||
9a77daac | 579 | |
fe43fa2f BG |
580 | /* |
581 | * __tdp_mmu_set_spte - Set a TDP MMU SPTE and handle the associated bookkeeping | |
582 | * @kvm: kvm instance | |
583 | * @iter: a tdp_iter instance currently on the SPTE that should be set | |
584 | * @new_spte: The value the SPTE should be set to | |
585 | * @record_acc_track: Notify the MM subsystem of changes to the accessed state | |
586 | * of the page. Should be set unless handling an MMU | |
587 | * notifier for access tracking. Leaving record_acc_track | |
588 | * unset in that case prevents page accesses from being | |
589 | * double counted. | |
590 | * @record_dirty_log: Record the page as dirty in the dirty bitmap if | |
591 | * appropriate for the change being made. Should be set | |
592 | * unless performing certain dirty logging operations. | |
593 | * Leaving record_dirty_log unset in that case prevents page | |
594 | * writes from being double counted. | |
595 | */ | |
f8e14497 | 596 | static inline void __tdp_mmu_set_spte(struct kvm *kvm, struct tdp_iter *iter, |
a6a0b05d BG |
597 | u64 new_spte, bool record_acc_track, |
598 | bool record_dirty_log) | |
faaf05b0 | 599 | { |
531810ca | 600 | lockdep_assert_held_write(&kvm->mmu_lock); |
3a9a4aa5 | 601 | |
08f07c80 BG |
602 | /* |
603 | * No thread should be using this function to set SPTEs to the | |
604 | * temporary removed SPTE value. | |
605 | * If operating under the MMU lock in read mode, tdp_mmu_set_spte_atomic | |
606 | * should be used. If operating under the MMU lock in write mode, the | |
607 | * use of the removed SPTE should not be necessary. | |
608 | */ | |
7a51393a | 609 | WARN_ON(is_removed_spte(iter->old_spte)); |
08f07c80 | 610 | |
7cca2d0b | 611 | WRITE_ONCE(*rcu_dereference(iter->sptep), new_spte); |
f8e14497 | 612 | |
08889894 SC |
613 | __handle_changed_spte(kvm, iter->as_id, iter->gfn, iter->old_spte, |
614 | new_spte, iter->level, false); | |
f8e14497 BG |
615 | if (record_acc_track) |
616 | handle_changed_spte_acc_track(iter->old_spte, new_spte, | |
617 | iter->level); | |
a6a0b05d | 618 | if (record_dirty_log) |
08889894 | 619 | handle_changed_spte_dirty_log(kvm, iter->as_id, iter->gfn, |
a6a0b05d BG |
620 | iter->old_spte, new_spte, |
621 | iter->level); | |
f8e14497 BG |
622 | } |
623 | ||
624 | static inline void tdp_mmu_set_spte(struct kvm *kvm, struct tdp_iter *iter, | |
625 | u64 new_spte) | |
626 | { | |
a6a0b05d | 627 | __tdp_mmu_set_spte(kvm, iter, new_spte, true, true); |
f8e14497 | 628 | } |
faaf05b0 | 629 | |
f8e14497 BG |
630 | static inline void tdp_mmu_set_spte_no_acc_track(struct kvm *kvm, |
631 | struct tdp_iter *iter, | |
632 | u64 new_spte) | |
633 | { | |
a6a0b05d BG |
634 | __tdp_mmu_set_spte(kvm, iter, new_spte, false, true); |
635 | } | |
636 | ||
637 | static inline void tdp_mmu_set_spte_no_dirty_log(struct kvm *kvm, | |
638 | struct tdp_iter *iter, | |
639 | u64 new_spte) | |
640 | { | |
641 | __tdp_mmu_set_spte(kvm, iter, new_spte, true, false); | |
faaf05b0 BG |
642 | } |
643 | ||
644 | #define tdp_root_for_each_pte(_iter, _root, _start, _end) \ | |
645 | for_each_tdp_pte(_iter, _root->spt, _root->role.level, _start, _end) | |
646 | ||
f8e14497 BG |
647 | #define tdp_root_for_each_leaf_pte(_iter, _root, _start, _end) \ |
648 | tdp_root_for_each_pte(_iter, _root, _start, _end) \ | |
649 | if (!is_shadow_present_pte(_iter.old_spte) || \ | |
650 | !is_last_spte(_iter.old_spte, _iter.level)) \ | |
651 | continue; \ | |
652 | else | |
653 | ||
bb18842e BG |
654 | #define tdp_mmu_for_each_pte(_iter, _mmu, _start, _end) \ |
655 | for_each_tdp_pte(_iter, __va(_mmu->root_hpa), \ | |
656 | _mmu->shadow_root_level, _start, _end) | |
657 | ||
e28a436c BG |
658 | /* |
659 | * Yield if the MMU lock is contended or this thread needs to return control | |
660 | * to the scheduler. | |
661 | * | |
e139a34e BG |
662 | * If this function should yield and flush is set, it will perform a remote |
663 | * TLB flush before yielding. | |
664 | * | |
e28a436c | 665 | * If this function yields, it will also reset the tdp_iter's walk over the |
ed5e484b BG |
666 | * paging structure and the calling function should skip to the next |
667 | * iteration to allow the iterator to continue its traversal from the | |
668 | * paging structure root. | |
e28a436c BG |
669 | * |
670 | * Return true if this function yielded and the iterator's traversal was reset. | |
671 | * Return false if a yield was not needed. | |
672 | */ | |
e139a34e | 673 | static inline bool tdp_mmu_iter_cond_resched(struct kvm *kvm, |
6103bc07 BG |
674 | struct tdp_iter *iter, bool flush, |
675 | bool shared) | |
a6a0b05d | 676 | { |
ed5e484b BG |
677 | /* Ensure forward progress has been made before yielding. */ |
678 | if (iter->next_last_level_gfn == iter->yielded_gfn) | |
679 | return false; | |
680 | ||
531810ca | 681 | if (need_resched() || rwlock_needbreak(&kvm->mmu_lock)) { |
7cca2d0b BG |
682 | rcu_read_unlock(); |
683 | ||
e139a34e BG |
684 | if (flush) |
685 | kvm_flush_remote_tlbs(kvm); | |
686 | ||
6103bc07 BG |
687 | if (shared) |
688 | cond_resched_rwlock_read(&kvm->mmu_lock); | |
689 | else | |
690 | cond_resched_rwlock_write(&kvm->mmu_lock); | |
691 | ||
7cca2d0b | 692 | rcu_read_lock(); |
ed5e484b BG |
693 | |
694 | WARN_ON(iter->gfn > iter->next_last_level_gfn); | |
695 | ||
b601c3bc | 696 | tdp_iter_restart(iter); |
ed5e484b | 697 | |
e28a436c | 698 | return true; |
a6a0b05d | 699 | } |
e28a436c BG |
700 | |
701 | return false; | |
a6a0b05d BG |
702 | } |
703 | ||
faaf05b0 BG |
704 | /* |
705 | * Tears down the mappings for the range of gfns, [start, end), and frees the | |
706 | * non-root pages mapping GFNs strictly within that range. Returns true if | |
707 | * SPTEs have been cleared and a TLB flush is needed before releasing the | |
708 | * MMU lock. | |
6103bc07 | 709 | * |
063afacd BG |
710 | * If can_yield is true, will release the MMU lock and reschedule if the |
711 | * scheduler needs the CPU or there is contention on the MMU lock. If this | |
712 | * function cannot yield, it will not release the MMU lock or reschedule and | |
713 | * the caller must ensure it does not supply too large a GFN range, or the | |
6103bc07 BG |
714 | * operation can cause a soft lockup. |
715 | * | |
716 | * If shared is true, this thread holds the MMU lock in read mode and must | |
717 | * account for the possibility that other threads are modifying the paging | |
718 | * structures concurrently. If shared is false, this thread should hold the | |
719 | * MMU lock in write mode. | |
faaf05b0 BG |
720 | */ |
721 | static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, | |
6103bc07 BG |
722 | gfn_t start, gfn_t end, bool can_yield, bool flush, |
723 | bool shared) | |
faaf05b0 BG |
724 | { |
725 | struct tdp_iter iter; | |
faaf05b0 | 726 | |
6103bc07 BG |
727 | kvm_lockdep_assert_mmu_lock_held(kvm, shared); |
728 | ||
7cca2d0b BG |
729 | rcu_read_lock(); |
730 | ||
faaf05b0 | 731 | tdp_root_for_each_pte(iter, root, start, end) { |
6103bc07 | 732 | retry: |
1af4a960 | 733 | if (can_yield && |
6103bc07 | 734 | tdp_mmu_iter_cond_resched(kvm, &iter, flush, shared)) { |
a835429c | 735 | flush = false; |
1af4a960 BG |
736 | continue; |
737 | } | |
738 | ||
faaf05b0 BG |
739 | if (!is_shadow_present_pte(iter.old_spte)) |
740 | continue; | |
741 | ||
742 | /* | |
743 | * If this is a non-last-level SPTE that covers a larger range | |
744 | * than should be zapped, continue, and zap the mappings at a | |
745 | * lower level. | |
746 | */ | |
747 | if ((iter.gfn < start || | |
748 | iter.gfn + KVM_PAGES_PER_HPAGE(iter.level) > end) && | |
749 | !is_last_spte(iter.old_spte, iter.level)) | |
750 | continue; | |
751 | ||
6103bc07 BG |
752 | if (!shared) { |
753 | tdp_mmu_set_spte(kvm, &iter, 0); | |
754 | flush = true; | |
755 | } else if (!tdp_mmu_zap_spte_atomic(kvm, &iter)) { | |
756 | /* | |
757 | * The iter must explicitly re-read the SPTE because | |
758 | * the atomic cmpxchg failed. | |
759 | */ | |
760 | iter.old_spte = READ_ONCE(*rcu_dereference(iter.sptep)); | |
761 | goto retry; | |
762 | } | |
faaf05b0 | 763 | } |
7cca2d0b BG |
764 | |
765 | rcu_read_unlock(); | |
a835429c | 766 | return flush; |
faaf05b0 BG |
767 | } |
768 | ||
769 | /* | |
770 | * Tears down the mappings for the range of gfns, [start, end), and frees the | |
771 | * non-root pages mapping GFNs strictly within that range. Returns true if | |
772 | * SPTEs have been cleared and a TLB flush is needed before releasing the | |
773 | * MMU lock. | |
6103bc07 BG |
774 | * |
775 | * If shared is true, this thread holds the MMU lock in read mode and must | |
776 | * account for the possibility that other threads are modifying the paging | |
777 | * structures concurrently. If shared is false, this thread should hold the | |
778 | * MMU in write mode. | |
faaf05b0 | 779 | */ |
2b9663d8 | 780 | bool __kvm_tdp_mmu_zap_gfn_range(struct kvm *kvm, int as_id, gfn_t start, |
6103bc07 BG |
781 | gfn_t end, bool can_yield, bool flush, |
782 | bool shared) | |
faaf05b0 BG |
783 | { |
784 | struct kvm_mmu_page *root; | |
faaf05b0 | 785 | |
6103bc07 BG |
786 | for_each_tdp_mmu_root_yield_safe(kvm, root, as_id, shared) |
787 | flush = zap_gfn_range(kvm, root, start, end, can_yield, flush, | |
788 | shared); | |
faaf05b0 | 789 | |
faaf05b0 BG |
790 | return flush; |
791 | } | |
792 | ||
793 | void kvm_tdp_mmu_zap_all(struct kvm *kvm) | |
794 | { | |
339f5a7f | 795 | gfn_t max_gfn = 1ULL << (shadow_phys_bits - PAGE_SHIFT); |
2b9663d8 SC |
796 | bool flush = false; |
797 | int i; | |
798 | ||
799 | for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) | |
6103bc07 BG |
800 | flush = kvm_tdp_mmu_zap_gfn_range(kvm, i, 0, max_gfn, |
801 | flush, false); | |
faaf05b0 | 802 | |
faaf05b0 BG |
803 | if (flush) |
804 | kvm_flush_remote_tlbs(kvm); | |
805 | } | |
bb18842e | 806 | |
4c6654bd BG |
807 | static struct kvm_mmu_page *next_invalidated_root(struct kvm *kvm, |
808 | struct kvm_mmu_page *prev_root) | |
809 | { | |
810 | struct kvm_mmu_page *next_root; | |
811 | ||
812 | if (prev_root) | |
813 | next_root = list_next_or_null_rcu(&kvm->arch.tdp_mmu_roots, | |
814 | &prev_root->link, | |
815 | typeof(*prev_root), link); | |
816 | else | |
817 | next_root = list_first_or_null_rcu(&kvm->arch.tdp_mmu_roots, | |
818 | typeof(*next_root), link); | |
819 | ||
820 | while (next_root && !(next_root->role.invalid && | |
821 | refcount_read(&next_root->tdp_mmu_root_count))) | |
822 | next_root = list_next_or_null_rcu(&kvm->arch.tdp_mmu_roots, | |
823 | &next_root->link, | |
824 | typeof(*next_root), link); | |
825 | ||
826 | return next_root; | |
827 | } | |
828 | ||
829 | /* | |
830 | * Since kvm_tdp_mmu_zap_all_fast has acquired a reference to each | |
831 | * invalidated root, they will not be freed until this function drops the | |
832 | * reference. Before dropping that reference, tear down the paging | |
833 | * structure so that whichever thread does drop the last reference | |
834 | * only has to do a trivial amount of work. Since the roots are invalid, | |
835 | * no new SPTEs should be created under them. | |
836 | */ | |
837 | void kvm_tdp_mmu_zap_invalidated_roots(struct kvm *kvm) | |
838 | { | |
839 | gfn_t max_gfn = 1ULL << (shadow_phys_bits - PAGE_SHIFT); | |
840 | struct kvm_mmu_page *next_root; | |
841 | struct kvm_mmu_page *root; | |
842 | bool flush = false; | |
843 | ||
844 | lockdep_assert_held_read(&kvm->mmu_lock); | |
845 | ||
846 | rcu_read_lock(); | |
847 | ||
848 | root = next_invalidated_root(kvm, NULL); | |
849 | ||
850 | while (root) { | |
851 | next_root = next_invalidated_root(kvm, root); | |
852 | ||
853 | rcu_read_unlock(); | |
854 | ||
855 | flush = zap_gfn_range(kvm, root, 0, max_gfn, true, flush, | |
856 | true); | |
857 | ||
858 | /* | |
859 | * Put the reference acquired in | |
860 | * kvm_tdp_mmu_invalidate_roots | |
861 | */ | |
862 | kvm_tdp_mmu_put_root(kvm, root, true); | |
863 | ||
864 | root = next_root; | |
865 | ||
866 | rcu_read_lock(); | |
867 | } | |
868 | ||
869 | rcu_read_unlock(); | |
faaf05b0 | 870 | |
faaf05b0 BG |
871 | if (flush) |
872 | kvm_flush_remote_tlbs(kvm); | |
873 | } | |
bb18842e | 874 | |
b7cccd39 BG |
875 | /* |
876 | * Mark each TDP MMU root as invalid so that other threads | |
877 | * will drop their references and allow the root count to | |
878 | * go to 0. | |
879 | * | |
4c6654bd BG |
880 | * Also take a reference on all roots so that this thread |
881 | * can do the bulk of the work required to free the roots | |
882 | * once they are invalidated. Without this reference, a | |
883 | * vCPU thread might drop the last reference to a root and | |
884 | * get stuck with tearing down the entire paging structure. | |
885 | * | |
886 | * Roots which have a zero refcount should be skipped as | |
887 | * they're already being torn down. | |
888 | * Already invalid roots should be referenced again so that | |
889 | * they aren't freed before kvm_tdp_mmu_zap_all_fast is | |
890 | * done with them. | |
891 | * | |
b7cccd39 BG |
892 | * This has essentially the same effect for the TDP MMU |
893 | * as updating mmu_valid_gen does for the shadow MMU. | |
894 | */ | |
895 | void kvm_tdp_mmu_invalidate_all_roots(struct kvm *kvm) | |
896 | { | |
897 | struct kvm_mmu_page *root; | |
898 | ||
899 | lockdep_assert_held_write(&kvm->mmu_lock); | |
900 | list_for_each_entry(root, &kvm->arch.tdp_mmu_roots, link) | |
4c6654bd BG |
901 | if (refcount_inc_not_zero(&root->tdp_mmu_root_count)) |
902 | root->role.invalid = true; | |
b7cccd39 BG |
903 | } |
904 | ||
bb18842e BG |
905 | /* |
906 | * Installs a last-level SPTE to handle a TDP page fault. | |
907 | * (NPT/EPT violation/misconfiguration) | |
908 | */ | |
909 | static int tdp_mmu_map_handle_target_level(struct kvm_vcpu *vcpu, int write, | |
910 | int map_writable, | |
911 | struct tdp_iter *iter, | |
912 | kvm_pfn_t pfn, bool prefault) | |
913 | { | |
914 | u64 new_spte; | |
915 | int ret = 0; | |
916 | int make_spte_ret = 0; | |
917 | ||
9a77daac | 918 | if (unlikely(is_noslot_pfn(pfn))) |
bb18842e | 919 | new_spte = make_mmio_spte(vcpu, iter->gfn, ACC_ALL); |
9a77daac | 920 | else |
bb18842e BG |
921 | make_spte_ret = make_spte(vcpu, ACC_ALL, iter->level, iter->gfn, |
922 | pfn, iter->old_spte, prefault, true, | |
923 | map_writable, !shadow_accessed_mask, | |
924 | &new_spte); | |
925 | ||
926 | if (new_spte == iter->old_spte) | |
927 | ret = RET_PF_SPURIOUS; | |
9a77daac BG |
928 | else if (!tdp_mmu_set_spte_atomic(vcpu->kvm, iter, new_spte)) |
929 | return RET_PF_RETRY; | |
bb18842e BG |
930 | |
931 | /* | |
932 | * If the page fault was caused by a write but the page is write | |
933 | * protected, emulation is needed. If the emulation was skipped, | |
934 | * the vCPU would have the same fault again. | |
935 | */ | |
936 | if (make_spte_ret & SET_SPTE_WRITE_PROTECTED_PT) { | |
937 | if (write) | |
938 | ret = RET_PF_EMULATE; | |
939 | kvm_make_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu); | |
940 | } | |
941 | ||
942 | /* If a MMIO SPTE is installed, the MMIO will need to be emulated. */ | |
9a77daac BG |
943 | if (unlikely(is_mmio_spte(new_spte))) { |
944 | trace_mark_mmio_spte(rcu_dereference(iter->sptep), iter->gfn, | |
945 | new_spte); | |
bb18842e | 946 | ret = RET_PF_EMULATE; |
3849e092 | 947 | } else { |
9a77daac BG |
948 | trace_kvm_mmu_set_spte(iter->level, iter->gfn, |
949 | rcu_dereference(iter->sptep)); | |
3849e092 | 950 | } |
bb18842e | 951 | |
bb18842e BG |
952 | if (!prefault) |
953 | vcpu->stat.pf_fixed++; | |
954 | ||
955 | return ret; | |
956 | } | |
957 | ||
958 | /* | |
959 | * Handle a TDP page fault (NPT/EPT violation/misconfiguration) by installing | |
960 | * page tables and SPTEs to translate the faulting guest physical address. | |
961 | */ | |
962 | int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code, | |
963 | int map_writable, int max_level, kvm_pfn_t pfn, | |
964 | bool prefault) | |
965 | { | |
966 | bool nx_huge_page_workaround_enabled = is_nx_huge_page_enabled(); | |
967 | bool write = error_code & PFERR_WRITE_MASK; | |
968 | bool exec = error_code & PFERR_FETCH_MASK; | |
969 | bool huge_page_disallowed = exec && nx_huge_page_workaround_enabled; | |
970 | struct kvm_mmu *mmu = vcpu->arch.mmu; | |
971 | struct tdp_iter iter; | |
89c0fd49 | 972 | struct kvm_mmu_page *sp; |
bb18842e BG |
973 | u64 *child_pt; |
974 | u64 new_spte; | |
975 | int ret; | |
976 | gfn_t gfn = gpa >> PAGE_SHIFT; | |
977 | int level; | |
978 | int req_level; | |
979 | ||
980 | if (WARN_ON(!VALID_PAGE(vcpu->arch.mmu->root_hpa))) | |
981 | return RET_PF_RETRY; | |
982 | if (WARN_ON(!is_tdp_mmu_root(vcpu->kvm, vcpu->arch.mmu->root_hpa))) | |
983 | return RET_PF_RETRY; | |
984 | ||
985 | level = kvm_mmu_hugepage_adjust(vcpu, gfn, max_level, &pfn, | |
986 | huge_page_disallowed, &req_level); | |
987 | ||
988 | trace_kvm_mmu_spte_requested(gpa, level, pfn); | |
7cca2d0b BG |
989 | |
990 | rcu_read_lock(); | |
991 | ||
bb18842e BG |
992 | tdp_mmu_for_each_pte(iter, mmu, gfn, gfn + 1) { |
993 | if (nx_huge_page_workaround_enabled) | |
994 | disallowed_hugepage_adjust(iter.old_spte, gfn, | |
995 | iter.level, &pfn, &level); | |
996 | ||
997 | if (iter.level == level) | |
998 | break; | |
999 | ||
1000 | /* | |
1001 | * If there is an SPTE mapping a large page at a higher level | |
1002 | * than the target, that SPTE must be cleared and replaced | |
1003 | * with a non-leaf SPTE. | |
1004 | */ | |
1005 | if (is_shadow_present_pte(iter.old_spte) && | |
1006 | is_large_pte(iter.old_spte)) { | |
08f07c80 | 1007 | if (!tdp_mmu_zap_spte_atomic(vcpu->kvm, &iter)) |
9a77daac | 1008 | break; |
bb18842e | 1009 | |
bb18842e BG |
1010 | /* |
1011 | * The iter must explicitly re-read the spte here | |
1012 | * because the new value informs the !present | |
1013 | * path below. | |
1014 | */ | |
7cca2d0b | 1015 | iter.old_spte = READ_ONCE(*rcu_dereference(iter.sptep)); |
bb18842e BG |
1016 | } |
1017 | ||
1018 | if (!is_shadow_present_pte(iter.old_spte)) { | |
ff76d506 KH |
1019 | /* |
1020 | * If SPTE has been forzen by another thread, just | |
1021 | * give up and retry, avoiding unnecessary page table | |
1022 | * allocation and free. | |
1023 | */ | |
1024 | if (is_removed_spte(iter.old_spte)) | |
1025 | break; | |
1026 | ||
89c0fd49 | 1027 | sp = alloc_tdp_mmu_page(vcpu, iter.gfn, iter.level); |
89c0fd49 | 1028 | child_pt = sp->spt; |
a9442f59 | 1029 | |
bb18842e BG |
1030 | new_spte = make_nonleaf_spte(child_pt, |
1031 | !shadow_accessed_mask); | |
1032 | ||
9a77daac BG |
1033 | if (tdp_mmu_set_spte_atomic(vcpu->kvm, &iter, |
1034 | new_spte)) { | |
1035 | tdp_mmu_link_page(vcpu->kvm, sp, true, | |
1036 | huge_page_disallowed && | |
1037 | req_level >= iter.level); | |
1038 | ||
1039 | trace_kvm_mmu_get_page(sp, true); | |
1040 | } else { | |
1041 | tdp_mmu_free_sp(sp); | |
1042 | break; | |
1043 | } | |
bb18842e BG |
1044 | } |
1045 | } | |
1046 | ||
9a77daac | 1047 | if (iter.level != level) { |
7cca2d0b | 1048 | rcu_read_unlock(); |
bb18842e | 1049 | return RET_PF_RETRY; |
7cca2d0b | 1050 | } |
bb18842e BG |
1051 | |
1052 | ret = tdp_mmu_map_handle_target_level(vcpu, write, map_writable, &iter, | |
1053 | pfn, prefault); | |
7cca2d0b | 1054 | rcu_read_unlock(); |
bb18842e BG |
1055 | |
1056 | return ret; | |
1057 | } | |
063afacd | 1058 | |
3039bcc7 SC |
1059 | bool kvm_tdp_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range, |
1060 | bool flush) | |
063afacd | 1061 | { |
063afacd | 1062 | struct kvm_mmu_page *root; |
063afacd | 1063 | |
3039bcc7 SC |
1064 | for_each_tdp_mmu_root(kvm, root, range->slot->as_id) |
1065 | flush |= zap_gfn_range(kvm, root, range->start, range->end, | |
6103bc07 | 1066 | range->may_block, flush, false); |
063afacd | 1067 | |
3039bcc7 | 1068 | return flush; |
063afacd BG |
1069 | } |
1070 | ||
3039bcc7 SC |
1071 | typedef bool (*tdp_handler_t)(struct kvm *kvm, struct tdp_iter *iter, |
1072 | struct kvm_gfn_range *range); | |
063afacd | 1073 | |
3039bcc7 SC |
1074 | static __always_inline bool kvm_tdp_mmu_handle_gfn(struct kvm *kvm, |
1075 | struct kvm_gfn_range *range, | |
1076 | tdp_handler_t handler) | |
063afacd | 1077 | { |
3039bcc7 SC |
1078 | struct kvm_mmu_page *root; |
1079 | struct tdp_iter iter; | |
1080 | bool ret = false; | |
1081 | ||
1082 | rcu_read_lock(); | |
1083 | ||
e1eed584 SC |
1084 | /* |
1085 | * Don't support rescheduling, none of the MMU notifiers that funnel | |
1086 | * into this helper allow blocking; it'd be dead, wasteful code. | |
1087 | */ | |
3039bcc7 SC |
1088 | for_each_tdp_mmu_root(kvm, root, range->slot->as_id) { |
1089 | tdp_root_for_each_leaf_pte(iter, root, range->start, range->end) | |
1090 | ret |= handler(kvm, &iter, range); | |
1091 | } | |
1092 | ||
1093 | rcu_read_unlock(); | |
1094 | ||
1095 | return ret; | |
063afacd | 1096 | } |
f8e14497 BG |
1097 | |
1098 | /* | |
1099 | * Mark the SPTEs range of GFNs [start, end) unaccessed and return non-zero | |
1100 | * if any of the GFNs in the range have been accessed. | |
1101 | */ | |
3039bcc7 SC |
1102 | static bool age_gfn_range(struct kvm *kvm, struct tdp_iter *iter, |
1103 | struct kvm_gfn_range *range) | |
f8e14497 | 1104 | { |
f8e14497 BG |
1105 | u64 new_spte = 0; |
1106 | ||
3039bcc7 SC |
1107 | /* If we have a non-accessed entry we don't need to change the pte. */ |
1108 | if (!is_accessed_spte(iter->old_spte)) | |
1109 | return false; | |
7cca2d0b | 1110 | |
3039bcc7 SC |
1111 | new_spte = iter->old_spte; |
1112 | ||
1113 | if (spte_ad_enabled(new_spte)) { | |
1114 | new_spte &= ~shadow_accessed_mask; | |
1115 | } else { | |
f8e14497 | 1116 | /* |
3039bcc7 SC |
1117 | * Capture the dirty status of the page, so that it doesn't get |
1118 | * lost when the SPTE is marked for access tracking. | |
f8e14497 | 1119 | */ |
3039bcc7 SC |
1120 | if (is_writable_pte(new_spte)) |
1121 | kvm_set_pfn_dirty(spte_to_pfn(new_spte)); | |
f8e14497 | 1122 | |
3039bcc7 | 1123 | new_spte = mark_spte_for_access_track(new_spte); |
f8e14497 BG |
1124 | } |
1125 | ||
3039bcc7 | 1126 | tdp_mmu_set_spte_no_acc_track(kvm, iter, new_spte); |
7cca2d0b | 1127 | |
3039bcc7 | 1128 | return true; |
f8e14497 BG |
1129 | } |
1130 | ||
3039bcc7 | 1131 | bool kvm_tdp_mmu_age_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range) |
f8e14497 | 1132 | { |
3039bcc7 | 1133 | return kvm_tdp_mmu_handle_gfn(kvm, range, age_gfn_range); |
f8e14497 BG |
1134 | } |
1135 | ||
3039bcc7 SC |
1136 | static bool test_age_gfn(struct kvm *kvm, struct tdp_iter *iter, |
1137 | struct kvm_gfn_range *range) | |
f8e14497 | 1138 | { |
3039bcc7 | 1139 | return is_accessed_spte(iter->old_spte); |
f8e14497 BG |
1140 | } |
1141 | ||
3039bcc7 | 1142 | bool kvm_tdp_mmu_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range) |
f8e14497 | 1143 | { |
3039bcc7 | 1144 | return kvm_tdp_mmu_handle_gfn(kvm, range, test_age_gfn); |
f8e14497 | 1145 | } |
1d8dd6b3 | 1146 | |
3039bcc7 SC |
1147 | static bool set_spte_gfn(struct kvm *kvm, struct tdp_iter *iter, |
1148 | struct kvm_gfn_range *range) | |
1d8dd6b3 | 1149 | { |
1d8dd6b3 | 1150 | u64 new_spte; |
7cca2d0b | 1151 | |
3039bcc7 SC |
1152 | /* Huge pages aren't expected to be modified without first being zapped. */ |
1153 | WARN_ON(pte_huge(range->pte) || range->start + 1 != range->end); | |
1d8dd6b3 | 1154 | |
3039bcc7 SC |
1155 | if (iter->level != PG_LEVEL_4K || |
1156 | !is_shadow_present_pte(iter->old_spte)) | |
1157 | return false; | |
1d8dd6b3 | 1158 | |
3039bcc7 SC |
1159 | /* |
1160 | * Note, when changing a read-only SPTE, it's not strictly necessary to | |
1161 | * zero the SPTE before setting the new PFN, but doing so preserves the | |
1162 | * invariant that the PFN of a present * leaf SPTE can never change. | |
1163 | * See __handle_changed_spte(). | |
1164 | */ | |
1165 | tdp_mmu_set_spte(kvm, iter, 0); | |
1d8dd6b3 | 1166 | |
3039bcc7 SC |
1167 | if (!pte_write(range->pte)) { |
1168 | new_spte = kvm_mmu_changed_pte_notifier_make_spte(iter->old_spte, | |
1169 | pte_pfn(range->pte)); | |
1d8dd6b3 | 1170 | |
3039bcc7 | 1171 | tdp_mmu_set_spte(kvm, iter, new_spte); |
1d8dd6b3 BG |
1172 | } |
1173 | ||
3039bcc7 | 1174 | return true; |
1d8dd6b3 BG |
1175 | } |
1176 | ||
3039bcc7 SC |
1177 | /* |
1178 | * Handle the changed_pte MMU notifier for the TDP MMU. | |
1179 | * data is a pointer to the new pte_t mapping the HVA specified by the MMU | |
1180 | * notifier. | |
1181 | * Returns non-zero if a flush is needed before releasing the MMU lock. | |
1182 | */ | |
1183 | bool kvm_tdp_mmu_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range) | |
1d8dd6b3 | 1184 | { |
3039bcc7 SC |
1185 | bool flush = kvm_tdp_mmu_handle_gfn(kvm, range, set_spte_gfn); |
1186 | ||
1187 | /* FIXME: return 'flush' instead of flushing here. */ | |
1188 | if (flush) | |
1189 | kvm_flush_remote_tlbs_with_address(kvm, range->start, 1); | |
1190 | ||
1191 | return false; | |
1d8dd6b3 BG |
1192 | } |
1193 | ||
a6a0b05d BG |
1194 | /* |
1195 | * Remove write access from all the SPTEs mapping GFNs [start, end). If | |
1196 | * skip_4k is set, SPTEs that map 4k pages, will not be write-protected. | |
1197 | * Returns true if an SPTE has been changed and the TLBs need to be flushed. | |
1198 | */ | |
1199 | static bool wrprot_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, | |
1200 | gfn_t start, gfn_t end, int min_level) | |
1201 | { | |
1202 | struct tdp_iter iter; | |
1203 | u64 new_spte; | |
1204 | bool spte_set = false; | |
1205 | ||
7cca2d0b BG |
1206 | rcu_read_lock(); |
1207 | ||
a6a0b05d BG |
1208 | BUG_ON(min_level > KVM_MAX_HUGEPAGE_LEVEL); |
1209 | ||
1210 | for_each_tdp_pte_min_level(iter, root->spt, root->role.level, | |
1211 | min_level, start, end) { | |
24ae4cfa BG |
1212 | retry: |
1213 | if (tdp_mmu_iter_cond_resched(kvm, &iter, false, true)) | |
1af4a960 BG |
1214 | continue; |
1215 | ||
a6a0b05d | 1216 | if (!is_shadow_present_pte(iter.old_spte) || |
0f99ee2c BG |
1217 | !is_last_spte(iter.old_spte, iter.level) || |
1218 | !(iter.old_spte & PT_WRITABLE_MASK)) | |
a6a0b05d BG |
1219 | continue; |
1220 | ||
1221 | new_spte = iter.old_spte & ~PT_WRITABLE_MASK; | |
1222 | ||
24ae4cfa BG |
1223 | if (!tdp_mmu_set_spte_atomic_no_dirty_log(kvm, &iter, |
1224 | new_spte)) { | |
1225 | /* | |
1226 | * The iter must explicitly re-read the SPTE because | |
1227 | * the atomic cmpxchg failed. | |
1228 | */ | |
1229 | iter.old_spte = READ_ONCE(*rcu_dereference(iter.sptep)); | |
1230 | goto retry; | |
1231 | } | |
a6a0b05d | 1232 | spte_set = true; |
a6a0b05d | 1233 | } |
7cca2d0b BG |
1234 | |
1235 | rcu_read_unlock(); | |
a6a0b05d BG |
1236 | return spte_set; |
1237 | } | |
1238 | ||
1239 | /* | |
1240 | * Remove write access from all the SPTEs mapping GFNs in the memslot. Will | |
1241 | * only affect leaf SPTEs down to min_level. | |
1242 | * Returns true if an SPTE has been changed and the TLBs need to be flushed. | |
1243 | */ | |
1244 | bool kvm_tdp_mmu_wrprot_slot(struct kvm *kvm, struct kvm_memory_slot *slot, | |
1245 | int min_level) | |
1246 | { | |
1247 | struct kvm_mmu_page *root; | |
a6a0b05d BG |
1248 | bool spte_set = false; |
1249 | ||
24ae4cfa | 1250 | lockdep_assert_held_read(&kvm->mmu_lock); |
a6a0b05d | 1251 | |
24ae4cfa | 1252 | for_each_tdp_mmu_root_yield_safe(kvm, root, slot->as_id, true) |
a6a0b05d BG |
1253 | spte_set |= wrprot_gfn_range(kvm, root, slot->base_gfn, |
1254 | slot->base_gfn + slot->npages, min_level); | |
a6a0b05d BG |
1255 | |
1256 | return spte_set; | |
1257 | } | |
1258 | ||
1259 | /* | |
1260 | * Clear the dirty status of all the SPTEs mapping GFNs in the memslot. If | |
1261 | * AD bits are enabled, this will involve clearing the dirty bit on each SPTE. | |
1262 | * If AD bits are not enabled, this will require clearing the writable bit on | |
1263 | * each SPTE. Returns true if an SPTE has been changed and the TLBs need to | |
1264 | * be flushed. | |
1265 | */ | |
1266 | static bool clear_dirty_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, | |
1267 | gfn_t start, gfn_t end) | |
1268 | { | |
1269 | struct tdp_iter iter; | |
1270 | u64 new_spte; | |
1271 | bool spte_set = false; | |
1272 | ||
7cca2d0b BG |
1273 | rcu_read_lock(); |
1274 | ||
a6a0b05d | 1275 | tdp_root_for_each_leaf_pte(iter, root, start, end) { |
24ae4cfa BG |
1276 | retry: |
1277 | if (tdp_mmu_iter_cond_resched(kvm, &iter, false, true)) | |
1af4a960 BG |
1278 | continue; |
1279 | ||
a6a0b05d BG |
1280 | if (spte_ad_need_write_protect(iter.old_spte)) { |
1281 | if (is_writable_pte(iter.old_spte)) | |
1282 | new_spte = iter.old_spte & ~PT_WRITABLE_MASK; | |
1283 | else | |
1284 | continue; | |
1285 | } else { | |
1286 | if (iter.old_spte & shadow_dirty_mask) | |
1287 | new_spte = iter.old_spte & ~shadow_dirty_mask; | |
1288 | else | |
1289 | continue; | |
1290 | } | |
1291 | ||
24ae4cfa BG |
1292 | if (!tdp_mmu_set_spte_atomic_no_dirty_log(kvm, &iter, |
1293 | new_spte)) { | |
1294 | /* | |
1295 | * The iter must explicitly re-read the SPTE because | |
1296 | * the atomic cmpxchg failed. | |
1297 | */ | |
1298 | iter.old_spte = READ_ONCE(*rcu_dereference(iter.sptep)); | |
1299 | goto retry; | |
1300 | } | |
a6a0b05d | 1301 | spte_set = true; |
a6a0b05d | 1302 | } |
7cca2d0b BG |
1303 | |
1304 | rcu_read_unlock(); | |
a6a0b05d BG |
1305 | return spte_set; |
1306 | } | |
1307 | ||
1308 | /* | |
1309 | * Clear the dirty status of all the SPTEs mapping GFNs in the memslot. If | |
1310 | * AD bits are enabled, this will involve clearing the dirty bit on each SPTE. | |
1311 | * If AD bits are not enabled, this will require clearing the writable bit on | |
1312 | * each SPTE. Returns true if an SPTE has been changed and the TLBs need to | |
1313 | * be flushed. | |
1314 | */ | |
1315 | bool kvm_tdp_mmu_clear_dirty_slot(struct kvm *kvm, struct kvm_memory_slot *slot) | |
1316 | { | |
1317 | struct kvm_mmu_page *root; | |
a6a0b05d BG |
1318 | bool spte_set = false; |
1319 | ||
24ae4cfa | 1320 | lockdep_assert_held_read(&kvm->mmu_lock); |
a6a0b05d | 1321 | |
24ae4cfa | 1322 | for_each_tdp_mmu_root_yield_safe(kvm, root, slot->as_id, true) |
a6a0b05d BG |
1323 | spte_set |= clear_dirty_gfn_range(kvm, root, slot->base_gfn, |
1324 | slot->base_gfn + slot->npages); | |
a6a0b05d BG |
1325 | |
1326 | return spte_set; | |
1327 | } | |
1328 | ||
1329 | /* | |
1330 | * Clears the dirty status of all the 4k SPTEs mapping GFNs for which a bit is | |
1331 | * set in mask, starting at gfn. The given memslot is expected to contain all | |
1332 | * the GFNs represented by set bits in the mask. If AD bits are enabled, | |
1333 | * clearing the dirty status will involve clearing the dirty bit on each SPTE | |
1334 | * or, if AD bits are not enabled, clearing the writable bit on each SPTE. | |
1335 | */ | |
1336 | static void clear_dirty_pt_masked(struct kvm *kvm, struct kvm_mmu_page *root, | |
1337 | gfn_t gfn, unsigned long mask, bool wrprot) | |
1338 | { | |
1339 | struct tdp_iter iter; | |
1340 | u64 new_spte; | |
1341 | ||
7cca2d0b BG |
1342 | rcu_read_lock(); |
1343 | ||
a6a0b05d BG |
1344 | tdp_root_for_each_leaf_pte(iter, root, gfn + __ffs(mask), |
1345 | gfn + BITS_PER_LONG) { | |
1346 | if (!mask) | |
1347 | break; | |
1348 | ||
1349 | if (iter.level > PG_LEVEL_4K || | |
1350 | !(mask & (1UL << (iter.gfn - gfn)))) | |
1351 | continue; | |
1352 | ||
f1b3b06a BG |
1353 | mask &= ~(1UL << (iter.gfn - gfn)); |
1354 | ||
a6a0b05d BG |
1355 | if (wrprot || spte_ad_need_write_protect(iter.old_spte)) { |
1356 | if (is_writable_pte(iter.old_spte)) | |
1357 | new_spte = iter.old_spte & ~PT_WRITABLE_MASK; | |
1358 | else | |
1359 | continue; | |
1360 | } else { | |
1361 | if (iter.old_spte & shadow_dirty_mask) | |
1362 | new_spte = iter.old_spte & ~shadow_dirty_mask; | |
1363 | else | |
1364 | continue; | |
1365 | } | |
1366 | ||
1367 | tdp_mmu_set_spte_no_dirty_log(kvm, &iter, new_spte); | |
a6a0b05d | 1368 | } |
7cca2d0b BG |
1369 | |
1370 | rcu_read_unlock(); | |
a6a0b05d BG |
1371 | } |
1372 | ||
1373 | /* | |
1374 | * Clears the dirty status of all the 4k SPTEs mapping GFNs for which a bit is | |
1375 | * set in mask, starting at gfn. The given memslot is expected to contain all | |
1376 | * the GFNs represented by set bits in the mask. If AD bits are enabled, | |
1377 | * clearing the dirty status will involve clearing the dirty bit on each SPTE | |
1378 | * or, if AD bits are not enabled, clearing the writable bit on each SPTE. | |
1379 | */ | |
1380 | void kvm_tdp_mmu_clear_dirty_pt_masked(struct kvm *kvm, | |
1381 | struct kvm_memory_slot *slot, | |
1382 | gfn_t gfn, unsigned long mask, | |
1383 | bool wrprot) | |
1384 | { | |
1385 | struct kvm_mmu_page *root; | |
a6a0b05d | 1386 | |
531810ca | 1387 | lockdep_assert_held_write(&kvm->mmu_lock); |
a3f15bda | 1388 | for_each_tdp_mmu_root(kvm, root, slot->as_id) |
a6a0b05d | 1389 | clear_dirty_pt_masked(kvm, root, gfn, mask, wrprot); |
a6a0b05d BG |
1390 | } |
1391 | ||
14881998 | 1392 | /* |
87aa9ec9 BG |
1393 | * Clear leaf entries which could be replaced by large mappings, for |
1394 | * GFNs within the slot. | |
14881998 | 1395 | */ |
af95b53e | 1396 | static bool zap_collapsible_spte_range(struct kvm *kvm, |
14881998 | 1397 | struct kvm_mmu_page *root, |
8ca6f063 | 1398 | const struct kvm_memory_slot *slot, |
af95b53e | 1399 | bool flush) |
14881998 | 1400 | { |
9eba50f8 SC |
1401 | gfn_t start = slot->base_gfn; |
1402 | gfn_t end = start + slot->npages; | |
14881998 BG |
1403 | struct tdp_iter iter; |
1404 | kvm_pfn_t pfn; | |
14881998 | 1405 | |
7cca2d0b BG |
1406 | rcu_read_lock(); |
1407 | ||
14881998 | 1408 | tdp_root_for_each_pte(iter, root, start, end) { |
2db6f772 BG |
1409 | retry: |
1410 | if (tdp_mmu_iter_cond_resched(kvm, &iter, flush, true)) { | |
af95b53e | 1411 | flush = false; |
1af4a960 BG |
1412 | continue; |
1413 | } | |
1414 | ||
14881998 | 1415 | if (!is_shadow_present_pte(iter.old_spte) || |
87aa9ec9 | 1416 | !is_last_spte(iter.old_spte, iter.level)) |
14881998 BG |
1417 | continue; |
1418 | ||
1419 | pfn = spte_to_pfn(iter.old_spte); | |
1420 | if (kvm_is_reserved_pfn(pfn) || | |
9eba50f8 SC |
1421 | iter.level >= kvm_mmu_max_mapping_level(kvm, slot, iter.gfn, |
1422 | pfn, PG_LEVEL_NUM)) | |
14881998 BG |
1423 | continue; |
1424 | ||
2db6f772 BG |
1425 | if (!tdp_mmu_zap_spte_atomic(kvm, &iter)) { |
1426 | /* | |
1427 | * The iter must explicitly re-read the SPTE because | |
1428 | * the atomic cmpxchg failed. | |
1429 | */ | |
1430 | iter.old_spte = READ_ONCE(*rcu_dereference(iter.sptep)); | |
1431 | goto retry; | |
1432 | } | |
af95b53e | 1433 | flush = true; |
14881998 BG |
1434 | } |
1435 | ||
7cca2d0b | 1436 | rcu_read_unlock(); |
af95b53e SC |
1437 | |
1438 | return flush; | |
14881998 BG |
1439 | } |
1440 | ||
1441 | /* | |
1442 | * Clear non-leaf entries (and free associated page tables) which could | |
1443 | * be replaced by large mappings, for GFNs within the slot. | |
1444 | */ | |
142ccde1 | 1445 | bool kvm_tdp_mmu_zap_collapsible_sptes(struct kvm *kvm, |
8ca6f063 BG |
1446 | const struct kvm_memory_slot *slot, |
1447 | bool flush) | |
14881998 BG |
1448 | { |
1449 | struct kvm_mmu_page *root; | |
14881998 | 1450 | |
2db6f772 | 1451 | lockdep_assert_held_read(&kvm->mmu_lock); |
14881998 | 1452 | |
2db6f772 | 1453 | for_each_tdp_mmu_root_yield_safe(kvm, root, slot->as_id, true) |
af95b53e | 1454 | flush = zap_collapsible_spte_range(kvm, root, slot, flush); |
af95b53e | 1455 | |
142ccde1 | 1456 | return flush; |
14881998 | 1457 | } |
46044f72 BG |
1458 | |
1459 | /* | |
1460 | * Removes write access on the last level SPTE mapping this GFN and unsets the | |
5fc3424f | 1461 | * MMU-writable bit to ensure future writes continue to be intercepted. |
46044f72 BG |
1462 | * Returns true if an SPTE was set and a TLB flush is needed. |
1463 | */ | |
1464 | static bool write_protect_gfn(struct kvm *kvm, struct kvm_mmu_page *root, | |
1465 | gfn_t gfn) | |
1466 | { | |
1467 | struct tdp_iter iter; | |
1468 | u64 new_spte; | |
1469 | bool spte_set = false; | |
1470 | ||
7cca2d0b BG |
1471 | rcu_read_lock(); |
1472 | ||
46044f72 BG |
1473 | tdp_root_for_each_leaf_pte(iter, root, gfn, gfn + 1) { |
1474 | if (!is_writable_pte(iter.old_spte)) | |
1475 | break; | |
1476 | ||
1477 | new_spte = iter.old_spte & | |
5fc3424f | 1478 | ~(PT_WRITABLE_MASK | shadow_mmu_writable_mask); |
46044f72 BG |
1479 | |
1480 | tdp_mmu_set_spte(kvm, &iter, new_spte); | |
1481 | spte_set = true; | |
1482 | } | |
1483 | ||
7cca2d0b BG |
1484 | rcu_read_unlock(); |
1485 | ||
46044f72 BG |
1486 | return spte_set; |
1487 | } | |
1488 | ||
1489 | /* | |
1490 | * Removes write access on the last level SPTE mapping this GFN and unsets the | |
5fc3424f | 1491 | * MMU-writable bit to ensure future writes continue to be intercepted. |
46044f72 BG |
1492 | * Returns true if an SPTE was set and a TLB flush is needed. |
1493 | */ | |
1494 | bool kvm_tdp_mmu_write_protect_gfn(struct kvm *kvm, | |
1495 | struct kvm_memory_slot *slot, gfn_t gfn) | |
1496 | { | |
1497 | struct kvm_mmu_page *root; | |
46044f72 BG |
1498 | bool spte_set = false; |
1499 | ||
531810ca | 1500 | lockdep_assert_held_write(&kvm->mmu_lock); |
a3f15bda | 1501 | for_each_tdp_mmu_root(kvm, root, slot->as_id) |
46044f72 | 1502 | spte_set |= write_protect_gfn(kvm, root, gfn); |
a3f15bda | 1503 | |
46044f72 BG |
1504 | return spte_set; |
1505 | } | |
1506 | ||
95fb5b02 BG |
1507 | /* |
1508 | * Return the level of the lowest level SPTE added to sptes. | |
1509 | * That SPTE may be non-present. | |
1510 | */ | |
39b4d43e SC |
1511 | int kvm_tdp_mmu_get_walk(struct kvm_vcpu *vcpu, u64 addr, u64 *sptes, |
1512 | int *root_level) | |
95fb5b02 BG |
1513 | { |
1514 | struct tdp_iter iter; | |
1515 | struct kvm_mmu *mmu = vcpu->arch.mmu; | |
95fb5b02 | 1516 | gfn_t gfn = addr >> PAGE_SHIFT; |
2aa07893 | 1517 | int leaf = -1; |
95fb5b02 | 1518 | |
39b4d43e | 1519 | *root_level = vcpu->arch.mmu->shadow_root_level; |
95fb5b02 | 1520 | |
7cca2d0b BG |
1521 | rcu_read_lock(); |
1522 | ||
95fb5b02 BG |
1523 | tdp_mmu_for_each_pte(iter, mmu, gfn, gfn + 1) { |
1524 | leaf = iter.level; | |
dde81f94 | 1525 | sptes[leaf] = iter.old_spte; |
95fb5b02 BG |
1526 | } |
1527 | ||
7cca2d0b BG |
1528 | rcu_read_unlock(); |
1529 | ||
95fb5b02 BG |
1530 | return leaf; |
1531 | } |