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KVM: MMU: Adjust page_header_update_slot() to accept a gfn instead of a gpa
[deliverable/linux.git] / drivers / kvm / mmu.c
1 /*
2 * Kernel-based Virtual Machine driver for Linux
3 *
4 * This module enables machines with Intel VT-x extensions to run virtual
5 * machines without emulation or binary translation.
6 *
7 * MMU support
8 *
9 * Copyright (C) 2006 Qumranet, Inc.
10 *
11 * Authors:
12 * Yaniv Kamay <yaniv@qumranet.com>
13 * Avi Kivity <avi@qumranet.com>
14 *
15 * This work is licensed under the terms of the GNU GPL, version 2. See
16 * the COPYING file in the top-level directory.
17 *
18 */
19
20 #include "vmx.h"
21 #include "kvm.h"
22 #include "x86.h"
23
24 #include <linux/types.h>
25 #include <linux/string.h>
26 #include <linux/mm.h>
27 #include <linux/highmem.h>
28 #include <linux/module.h>
29
30 #include <asm/page.h>
31 #include <asm/cmpxchg.h>
32 #include <asm/io.h>
33
34 #undef MMU_DEBUG
35
36 #undef AUDIT
37
38 #ifdef AUDIT
39 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg);
40 #else
41 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg) {}
42 #endif
43
44 #ifdef MMU_DEBUG
45
46 #define pgprintk(x...) do { if (dbg) printk(x); } while (0)
47 #define rmap_printk(x...) do { if (dbg) printk(x); } while (0)
48
49 #else
50
51 #define pgprintk(x...) do { } while (0)
52 #define rmap_printk(x...) do { } while (0)
53
54 #endif
55
56 #if defined(MMU_DEBUG) || defined(AUDIT)
57 static int dbg = 1;
58 #endif
59
60 #ifndef MMU_DEBUG
61 #define ASSERT(x) do { } while (0)
62 #else
63 #define ASSERT(x) \
64 if (!(x)) { \
65 printk(KERN_WARNING "assertion failed %s:%d: %s\n", \
66 __FILE__, __LINE__, #x); \
67 }
68 #endif
69
70 #define PT64_PT_BITS 9
71 #define PT64_ENT_PER_PAGE (1 << PT64_PT_BITS)
72 #define PT32_PT_BITS 10
73 #define PT32_ENT_PER_PAGE (1 << PT32_PT_BITS)
74
75 #define PT_WRITABLE_SHIFT 1
76
77 #define PT_PRESENT_MASK (1ULL << 0)
78 #define PT_WRITABLE_MASK (1ULL << PT_WRITABLE_SHIFT)
79 #define PT_USER_MASK (1ULL << 2)
80 #define PT_PWT_MASK (1ULL << 3)
81 #define PT_PCD_MASK (1ULL << 4)
82 #define PT_ACCESSED_MASK (1ULL << 5)
83 #define PT_DIRTY_MASK (1ULL << 6)
84 #define PT_PAGE_SIZE_MASK (1ULL << 7)
85 #define PT_PAT_MASK (1ULL << 7)
86 #define PT_GLOBAL_MASK (1ULL << 8)
87 #define PT64_NX_MASK (1ULL << 63)
88
89 #define PT_PAT_SHIFT 7
90 #define PT_DIR_PAT_SHIFT 12
91 #define PT_DIR_PAT_MASK (1ULL << PT_DIR_PAT_SHIFT)
92
93 #define PT32_DIR_PSE36_SIZE 4
94 #define PT32_DIR_PSE36_SHIFT 13
95 #define PT32_DIR_PSE36_MASK \
96 (((1ULL << PT32_DIR_PSE36_SIZE) - 1) << PT32_DIR_PSE36_SHIFT)
97
98
99 #define PT_FIRST_AVAIL_BITS_SHIFT 9
100 #define PT64_SECOND_AVAIL_BITS_SHIFT 52
101
102 #define PT_SHADOW_IO_MARK (1ULL << PT_FIRST_AVAIL_BITS_SHIFT)
103
104 #define VALID_PAGE(x) ((x) != INVALID_PAGE)
105
106 #define PT64_LEVEL_BITS 9
107
108 #define PT64_LEVEL_SHIFT(level) \
109 (PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS)
110
111 #define PT64_LEVEL_MASK(level) \
112 (((1ULL << PT64_LEVEL_BITS) - 1) << PT64_LEVEL_SHIFT(level))
113
114 #define PT64_INDEX(address, level)\
115 (((address) >> PT64_LEVEL_SHIFT(level)) & ((1 << PT64_LEVEL_BITS) - 1))
116
117
118 #define PT32_LEVEL_BITS 10
119
120 #define PT32_LEVEL_SHIFT(level) \
121 (PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS)
122
123 #define PT32_LEVEL_MASK(level) \
124 (((1ULL << PT32_LEVEL_BITS) - 1) << PT32_LEVEL_SHIFT(level))
125
126 #define PT32_INDEX(address, level)\
127 (((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))
128
129
130 #define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))
131 #define PT64_DIR_BASE_ADDR_MASK \
132 (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))
133
134 #define PT32_BASE_ADDR_MASK PAGE_MASK
135 #define PT32_DIR_BASE_ADDR_MASK \
136 (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
137
138 #define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK \
139 | PT64_NX_MASK)
140
141 #define PFERR_PRESENT_MASK (1U << 0)
142 #define PFERR_WRITE_MASK (1U << 1)
143 #define PFERR_USER_MASK (1U << 2)
144 #define PFERR_FETCH_MASK (1U << 4)
145
146 #define PT64_ROOT_LEVEL 4
147 #define PT32_ROOT_LEVEL 2
148 #define PT32E_ROOT_LEVEL 3
149
150 #define PT_DIRECTORY_LEVEL 2
151 #define PT_PAGE_TABLE_LEVEL 1
152
153 #define RMAP_EXT 4
154
155 struct kvm_rmap_desc {
156 u64 *shadow_ptes[RMAP_EXT];
157 struct kvm_rmap_desc *more;
158 };
159
160 static struct kmem_cache *pte_chain_cache;
161 static struct kmem_cache *rmap_desc_cache;
162 static struct kmem_cache *mmu_page_header_cache;
163
164 static u64 __read_mostly shadow_trap_nonpresent_pte;
165 static u64 __read_mostly shadow_notrap_nonpresent_pte;
166
167 void kvm_mmu_set_nonpresent_ptes(u64 trap_pte, u64 notrap_pte)
168 {
169 shadow_trap_nonpresent_pte = trap_pte;
170 shadow_notrap_nonpresent_pte = notrap_pte;
171 }
172 EXPORT_SYMBOL_GPL(kvm_mmu_set_nonpresent_ptes);
173
174 static int is_write_protection(struct kvm_vcpu *vcpu)
175 {
176 return vcpu->cr0 & X86_CR0_WP;
177 }
178
179 static int is_cpuid_PSE36(void)
180 {
181 return 1;
182 }
183
184 static int is_nx(struct kvm_vcpu *vcpu)
185 {
186 return vcpu->shadow_efer & EFER_NX;
187 }
188
189 static int is_present_pte(unsigned long pte)
190 {
191 return pte & PT_PRESENT_MASK;
192 }
193
194 static int is_shadow_present_pte(u64 pte)
195 {
196 pte &= ~PT_SHADOW_IO_MARK;
197 return pte != shadow_trap_nonpresent_pte
198 && pte != shadow_notrap_nonpresent_pte;
199 }
200
201 static int is_writeble_pte(unsigned long pte)
202 {
203 return pte & PT_WRITABLE_MASK;
204 }
205
206 static int is_dirty_pte(unsigned long pte)
207 {
208 return pte & PT_DIRTY_MASK;
209 }
210
211 static int is_io_pte(unsigned long pte)
212 {
213 return pte & PT_SHADOW_IO_MARK;
214 }
215
216 static int is_rmap_pte(u64 pte)
217 {
218 return pte != shadow_trap_nonpresent_pte
219 && pte != shadow_notrap_nonpresent_pte;
220 }
221
222 static gfn_t pse36_gfn_delta(u32 gpte)
223 {
224 int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT;
225
226 return (gpte & PT32_DIR_PSE36_MASK) << shift;
227 }
228
229 static void set_shadow_pte(u64 *sptep, u64 spte)
230 {
231 #ifdef CONFIG_X86_64
232 set_64bit((unsigned long *)sptep, spte);
233 #else
234 set_64bit((unsigned long long *)sptep, spte);
235 #endif
236 }
237
238 static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
239 struct kmem_cache *base_cache, int min)
240 {
241 void *obj;
242
243 if (cache->nobjs >= min)
244 return 0;
245 while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
246 obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
247 if (!obj)
248 return -ENOMEM;
249 cache->objects[cache->nobjs++] = obj;
250 }
251 return 0;
252 }
253
254 static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
255 {
256 while (mc->nobjs)
257 kfree(mc->objects[--mc->nobjs]);
258 }
259
260 static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
261 int min)
262 {
263 struct page *page;
264
265 if (cache->nobjs >= min)
266 return 0;
267 while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
268 page = alloc_page(GFP_KERNEL);
269 if (!page)
270 return -ENOMEM;
271 set_page_private(page, 0);
272 cache->objects[cache->nobjs++] = page_address(page);
273 }
274 return 0;
275 }
276
277 static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
278 {
279 while (mc->nobjs)
280 free_page((unsigned long)mc->objects[--mc->nobjs]);
281 }
282
283 static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
284 {
285 int r;
286
287 kvm_mmu_free_some_pages(vcpu);
288 r = mmu_topup_memory_cache(&vcpu->mmu_pte_chain_cache,
289 pte_chain_cache, 4);
290 if (r)
291 goto out;
292 r = mmu_topup_memory_cache(&vcpu->mmu_rmap_desc_cache,
293 rmap_desc_cache, 1);
294 if (r)
295 goto out;
296 r = mmu_topup_memory_cache_page(&vcpu->mmu_page_cache, 8);
297 if (r)
298 goto out;
299 r = mmu_topup_memory_cache(&vcpu->mmu_page_header_cache,
300 mmu_page_header_cache, 4);
301 out:
302 return r;
303 }
304
305 static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
306 {
307 mmu_free_memory_cache(&vcpu->mmu_pte_chain_cache);
308 mmu_free_memory_cache(&vcpu->mmu_rmap_desc_cache);
309 mmu_free_memory_cache_page(&vcpu->mmu_page_cache);
310 mmu_free_memory_cache(&vcpu->mmu_page_header_cache);
311 }
312
313 static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc,
314 size_t size)
315 {
316 void *p;
317
318 BUG_ON(!mc->nobjs);
319 p = mc->objects[--mc->nobjs];
320 memset(p, 0, size);
321 return p;
322 }
323
324 static struct kvm_pte_chain *mmu_alloc_pte_chain(struct kvm_vcpu *vcpu)
325 {
326 return mmu_memory_cache_alloc(&vcpu->mmu_pte_chain_cache,
327 sizeof(struct kvm_pte_chain));
328 }
329
330 static void mmu_free_pte_chain(struct kvm_pte_chain *pc)
331 {
332 kfree(pc);
333 }
334
335 static struct kvm_rmap_desc *mmu_alloc_rmap_desc(struct kvm_vcpu *vcpu)
336 {
337 return mmu_memory_cache_alloc(&vcpu->mmu_rmap_desc_cache,
338 sizeof(struct kvm_rmap_desc));
339 }
340
341 static void mmu_free_rmap_desc(struct kvm_rmap_desc *rd)
342 {
343 kfree(rd);
344 }
345
346 /*
347 * Take gfn and return the reverse mapping to it.
348 * Note: gfn must be unaliased before this function get called
349 */
350
351 static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn)
352 {
353 struct kvm_memory_slot *slot;
354
355 slot = gfn_to_memslot(kvm, gfn);
356 return &slot->rmap[gfn - slot->base_gfn];
357 }
358
359 /*
360 * Reverse mapping data structures:
361 *
362 * If rmapp bit zero is zero, then rmapp point to the shadw page table entry
363 * that points to page_address(page).
364 *
365 * If rmapp bit zero is one, (then rmap & ~1) points to a struct kvm_rmap_desc
366 * containing more mappings.
367 */
368 static void rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
369 {
370 struct kvm_mmu_page *page;
371 struct kvm_rmap_desc *desc;
372 unsigned long *rmapp;
373 int i;
374
375 if (!is_rmap_pte(*spte))
376 return;
377 gfn = unalias_gfn(vcpu->kvm, gfn);
378 page = page_header(__pa(spte));
379 page->gfns[spte - page->spt] = gfn;
380 rmapp = gfn_to_rmap(vcpu->kvm, gfn);
381 if (!*rmapp) {
382 rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte);
383 *rmapp = (unsigned long)spte;
384 } else if (!(*rmapp & 1)) {
385 rmap_printk("rmap_add: %p %llx 1->many\n", spte, *spte);
386 desc = mmu_alloc_rmap_desc(vcpu);
387 desc->shadow_ptes[0] = (u64 *)*rmapp;
388 desc->shadow_ptes[1] = spte;
389 *rmapp = (unsigned long)desc | 1;
390 } else {
391 rmap_printk("rmap_add: %p %llx many->many\n", spte, *spte);
392 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
393 while (desc->shadow_ptes[RMAP_EXT-1] && desc->more)
394 desc = desc->more;
395 if (desc->shadow_ptes[RMAP_EXT-1]) {
396 desc->more = mmu_alloc_rmap_desc(vcpu);
397 desc = desc->more;
398 }
399 for (i = 0; desc->shadow_ptes[i]; ++i)
400 ;
401 desc->shadow_ptes[i] = spte;
402 }
403 }
404
405 static void rmap_desc_remove_entry(unsigned long *rmapp,
406 struct kvm_rmap_desc *desc,
407 int i,
408 struct kvm_rmap_desc *prev_desc)
409 {
410 int j;
411
412 for (j = RMAP_EXT - 1; !desc->shadow_ptes[j] && j > i; --j)
413 ;
414 desc->shadow_ptes[i] = desc->shadow_ptes[j];
415 desc->shadow_ptes[j] = NULL;
416 if (j != 0)
417 return;
418 if (!prev_desc && !desc->more)
419 *rmapp = (unsigned long)desc->shadow_ptes[0];
420 else
421 if (prev_desc)
422 prev_desc->more = desc->more;
423 else
424 *rmapp = (unsigned long)desc->more | 1;
425 mmu_free_rmap_desc(desc);
426 }
427
428 static void rmap_remove(struct kvm *kvm, u64 *spte)
429 {
430 struct kvm_rmap_desc *desc;
431 struct kvm_rmap_desc *prev_desc;
432 struct kvm_mmu_page *page;
433 struct page *release_page;
434 unsigned long *rmapp;
435 int i;
436
437 if (!is_rmap_pte(*spte))
438 return;
439 page = page_header(__pa(spte));
440 release_page = pfn_to_page((*spte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT);
441 if (is_writeble_pte(*spte))
442 kvm_release_page_dirty(release_page);
443 else
444 kvm_release_page_clean(release_page);
445 rmapp = gfn_to_rmap(kvm, page->gfns[spte - page->spt]);
446 if (!*rmapp) {
447 printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte);
448 BUG();
449 } else if (!(*rmapp & 1)) {
450 rmap_printk("rmap_remove: %p %llx 1->0\n", spte, *spte);
451 if ((u64 *)*rmapp != spte) {
452 printk(KERN_ERR "rmap_remove: %p %llx 1->BUG\n",
453 spte, *spte);
454 BUG();
455 }
456 *rmapp = 0;
457 } else {
458 rmap_printk("rmap_remove: %p %llx many->many\n", spte, *spte);
459 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
460 prev_desc = NULL;
461 while (desc) {
462 for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i)
463 if (desc->shadow_ptes[i] == spte) {
464 rmap_desc_remove_entry(rmapp,
465 desc, i,
466 prev_desc);
467 return;
468 }
469 prev_desc = desc;
470 desc = desc->more;
471 }
472 BUG();
473 }
474 }
475
476 static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte)
477 {
478 struct kvm_rmap_desc *desc;
479 struct kvm_rmap_desc *prev_desc;
480 u64 *prev_spte;
481 int i;
482
483 if (!*rmapp)
484 return NULL;
485 else if (!(*rmapp & 1)) {
486 if (!spte)
487 return (u64 *)*rmapp;
488 return NULL;
489 }
490 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
491 prev_desc = NULL;
492 prev_spte = NULL;
493 while (desc) {
494 for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i) {
495 if (prev_spte == spte)
496 return desc->shadow_ptes[i];
497 prev_spte = desc->shadow_ptes[i];
498 }
499 desc = desc->more;
500 }
501 return NULL;
502 }
503
504 static void rmap_write_protect(struct kvm *kvm, u64 gfn)
505 {
506 unsigned long *rmapp;
507 u64 *spte;
508
509 gfn = unalias_gfn(kvm, gfn);
510 rmapp = gfn_to_rmap(kvm, gfn);
511
512 spte = rmap_next(kvm, rmapp, NULL);
513 while (spte) {
514 BUG_ON(!spte);
515 BUG_ON(!(*spte & PT_PRESENT_MASK));
516 rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
517 if (is_writeble_pte(*spte))
518 set_shadow_pte(spte, *spte & ~PT_WRITABLE_MASK);
519 kvm_flush_remote_tlbs(kvm);
520 spte = rmap_next(kvm, rmapp, spte);
521 }
522 }
523
524 #ifdef MMU_DEBUG
525 static int is_empty_shadow_page(u64 *spt)
526 {
527 u64 *pos;
528 u64 *end;
529
530 for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
531 if ((*pos & ~PT_SHADOW_IO_MARK) != shadow_trap_nonpresent_pte) {
532 printk(KERN_ERR "%s: %p %llx\n", __FUNCTION__,
533 pos, *pos);
534 return 0;
535 }
536 return 1;
537 }
538 #endif
539
540 static void kvm_mmu_free_page(struct kvm *kvm,
541 struct kvm_mmu_page *page_head)
542 {
543 ASSERT(is_empty_shadow_page(page_head->spt));
544 list_del(&page_head->link);
545 __free_page(virt_to_page(page_head->spt));
546 __free_page(virt_to_page(page_head->gfns));
547 kfree(page_head);
548 ++kvm->n_free_mmu_pages;
549 }
550
551 static unsigned kvm_page_table_hashfn(gfn_t gfn)
552 {
553 return gfn;
554 }
555
556 static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
557 u64 *parent_pte)
558 {
559 struct kvm_mmu_page *page;
560
561 if (!vcpu->kvm->n_free_mmu_pages)
562 return NULL;
563
564 page = mmu_memory_cache_alloc(&vcpu->mmu_page_header_cache,
565 sizeof *page);
566 page->spt = mmu_memory_cache_alloc(&vcpu->mmu_page_cache, PAGE_SIZE);
567 page->gfns = mmu_memory_cache_alloc(&vcpu->mmu_page_cache, PAGE_SIZE);
568 set_page_private(virt_to_page(page->spt), (unsigned long)page);
569 list_add(&page->link, &vcpu->kvm->active_mmu_pages);
570 ASSERT(is_empty_shadow_page(page->spt));
571 page->slot_bitmap = 0;
572 page->multimapped = 0;
573 page->parent_pte = parent_pte;
574 --vcpu->kvm->n_free_mmu_pages;
575 return page;
576 }
577
578 static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
579 struct kvm_mmu_page *page, u64 *parent_pte)
580 {
581 struct kvm_pte_chain *pte_chain;
582 struct hlist_node *node;
583 int i;
584
585 if (!parent_pte)
586 return;
587 if (!page->multimapped) {
588 u64 *old = page->parent_pte;
589
590 if (!old) {
591 page->parent_pte = parent_pte;
592 return;
593 }
594 page->multimapped = 1;
595 pte_chain = mmu_alloc_pte_chain(vcpu);
596 INIT_HLIST_HEAD(&page->parent_ptes);
597 hlist_add_head(&pte_chain->link, &page->parent_ptes);
598 pte_chain->parent_ptes[0] = old;
599 }
600 hlist_for_each_entry(pte_chain, node, &page->parent_ptes, link) {
601 if (pte_chain->parent_ptes[NR_PTE_CHAIN_ENTRIES-1])
602 continue;
603 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i)
604 if (!pte_chain->parent_ptes[i]) {
605 pte_chain->parent_ptes[i] = parent_pte;
606 return;
607 }
608 }
609 pte_chain = mmu_alloc_pte_chain(vcpu);
610 BUG_ON(!pte_chain);
611 hlist_add_head(&pte_chain->link, &page->parent_ptes);
612 pte_chain->parent_ptes[0] = parent_pte;
613 }
614
615 static void mmu_page_remove_parent_pte(struct kvm_mmu_page *page,
616 u64 *parent_pte)
617 {
618 struct kvm_pte_chain *pte_chain;
619 struct hlist_node *node;
620 int i;
621
622 if (!page->multimapped) {
623 BUG_ON(page->parent_pte != parent_pte);
624 page->parent_pte = NULL;
625 return;
626 }
627 hlist_for_each_entry(pte_chain, node, &page->parent_ptes, link)
628 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
629 if (!pte_chain->parent_ptes[i])
630 break;
631 if (pte_chain->parent_ptes[i] != parent_pte)
632 continue;
633 while (i + 1 < NR_PTE_CHAIN_ENTRIES
634 && pte_chain->parent_ptes[i + 1]) {
635 pte_chain->parent_ptes[i]
636 = pte_chain->parent_ptes[i + 1];
637 ++i;
638 }
639 pte_chain->parent_ptes[i] = NULL;
640 if (i == 0) {
641 hlist_del(&pte_chain->link);
642 mmu_free_pte_chain(pte_chain);
643 if (hlist_empty(&page->parent_ptes)) {
644 page->multimapped = 0;
645 page->parent_pte = NULL;
646 }
647 }
648 return;
649 }
650 BUG();
651 }
652
653 static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm *kvm,
654 gfn_t gfn)
655 {
656 unsigned index;
657 struct hlist_head *bucket;
658 struct kvm_mmu_page *page;
659 struct hlist_node *node;
660
661 pgprintk("%s: looking for gfn %lx\n", __FUNCTION__, gfn);
662 index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
663 bucket = &kvm->mmu_page_hash[index];
664 hlist_for_each_entry(page, node, bucket, hash_link)
665 if (page->gfn == gfn && !page->role.metaphysical) {
666 pgprintk("%s: found role %x\n",
667 __FUNCTION__, page->role.word);
668 return page;
669 }
670 return NULL;
671 }
672
673 static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
674 gfn_t gfn,
675 gva_t gaddr,
676 unsigned level,
677 int metaphysical,
678 unsigned hugepage_access,
679 u64 *parent_pte)
680 {
681 union kvm_mmu_page_role role;
682 unsigned index;
683 unsigned quadrant;
684 struct hlist_head *bucket;
685 struct kvm_mmu_page *page;
686 struct hlist_node *node;
687
688 role.word = 0;
689 role.glevels = vcpu->mmu.root_level;
690 role.level = level;
691 role.metaphysical = metaphysical;
692 role.hugepage_access = hugepage_access;
693 if (vcpu->mmu.root_level <= PT32_ROOT_LEVEL) {
694 quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
695 quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
696 role.quadrant = quadrant;
697 }
698 pgprintk("%s: looking gfn %lx role %x\n", __FUNCTION__,
699 gfn, role.word);
700 index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
701 bucket = &vcpu->kvm->mmu_page_hash[index];
702 hlist_for_each_entry(page, node, bucket, hash_link)
703 if (page->gfn == gfn && page->role.word == role.word) {
704 mmu_page_add_parent_pte(vcpu, page, parent_pte);
705 pgprintk("%s: found\n", __FUNCTION__);
706 return page;
707 }
708 page = kvm_mmu_alloc_page(vcpu, parent_pte);
709 if (!page)
710 return page;
711 pgprintk("%s: adding gfn %lx role %x\n", __FUNCTION__, gfn, role.word);
712 page->gfn = gfn;
713 page->role = role;
714 hlist_add_head(&page->hash_link, bucket);
715 vcpu->mmu.prefetch_page(vcpu, page);
716 if (!metaphysical)
717 rmap_write_protect(vcpu->kvm, gfn);
718 return page;
719 }
720
721 static void kvm_mmu_page_unlink_children(struct kvm *kvm,
722 struct kvm_mmu_page *page)
723 {
724 unsigned i;
725 u64 *pt;
726 u64 ent;
727
728 pt = page->spt;
729
730 if (page->role.level == PT_PAGE_TABLE_LEVEL) {
731 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
732 if (is_shadow_present_pte(pt[i]))
733 rmap_remove(kvm, &pt[i]);
734 pt[i] = shadow_trap_nonpresent_pte;
735 }
736 kvm_flush_remote_tlbs(kvm);
737 return;
738 }
739
740 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
741 ent = pt[i];
742
743 pt[i] = shadow_trap_nonpresent_pte;
744 if (!is_shadow_present_pte(ent))
745 continue;
746 ent &= PT64_BASE_ADDR_MASK;
747 mmu_page_remove_parent_pte(page_header(ent), &pt[i]);
748 }
749 kvm_flush_remote_tlbs(kvm);
750 }
751
752 static void kvm_mmu_put_page(struct kvm_mmu_page *page,
753 u64 *parent_pte)
754 {
755 mmu_page_remove_parent_pte(page, parent_pte);
756 }
757
758 static void kvm_mmu_reset_last_pte_updated(struct kvm *kvm)
759 {
760 int i;
761
762 for (i = 0; i < KVM_MAX_VCPUS; ++i)
763 if (kvm->vcpus[i])
764 kvm->vcpus[i]->last_pte_updated = NULL;
765 }
766
767 static void kvm_mmu_zap_page(struct kvm *kvm,
768 struct kvm_mmu_page *page)
769 {
770 u64 *parent_pte;
771
772 ++kvm->stat.mmu_shadow_zapped;
773 while (page->multimapped || page->parent_pte) {
774 if (!page->multimapped)
775 parent_pte = page->parent_pte;
776 else {
777 struct kvm_pte_chain *chain;
778
779 chain = container_of(page->parent_ptes.first,
780 struct kvm_pte_chain, link);
781 parent_pte = chain->parent_ptes[0];
782 }
783 BUG_ON(!parent_pte);
784 kvm_mmu_put_page(page, parent_pte);
785 set_shadow_pte(parent_pte, shadow_trap_nonpresent_pte);
786 }
787 kvm_mmu_page_unlink_children(kvm, page);
788 if (!page->root_count) {
789 hlist_del(&page->hash_link);
790 kvm_mmu_free_page(kvm, page);
791 } else
792 list_move(&page->link, &kvm->active_mmu_pages);
793 kvm_mmu_reset_last_pte_updated(kvm);
794 }
795
796 /*
797 * Changing the number of mmu pages allocated to the vm
798 * Note: if kvm_nr_mmu_pages is too small, you will get dead lock
799 */
800 void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages)
801 {
802 /*
803 * If we set the number of mmu pages to be smaller be than the
804 * number of actived pages , we must to free some mmu pages before we
805 * change the value
806 */
807
808 if ((kvm->n_alloc_mmu_pages - kvm->n_free_mmu_pages) >
809 kvm_nr_mmu_pages) {
810 int n_used_mmu_pages = kvm->n_alloc_mmu_pages
811 - kvm->n_free_mmu_pages;
812
813 while (n_used_mmu_pages > kvm_nr_mmu_pages) {
814 struct kvm_mmu_page *page;
815
816 page = container_of(kvm->active_mmu_pages.prev,
817 struct kvm_mmu_page, link);
818 kvm_mmu_zap_page(kvm, page);
819 n_used_mmu_pages--;
820 }
821 kvm->n_free_mmu_pages = 0;
822 }
823 else
824 kvm->n_free_mmu_pages += kvm_nr_mmu_pages
825 - kvm->n_alloc_mmu_pages;
826
827 kvm->n_alloc_mmu_pages = kvm_nr_mmu_pages;
828 }
829
830 static int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
831 {
832 unsigned index;
833 struct hlist_head *bucket;
834 struct kvm_mmu_page *page;
835 struct hlist_node *node, *n;
836 int r;
837
838 pgprintk("%s: looking for gfn %lx\n", __FUNCTION__, gfn);
839 r = 0;
840 index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
841 bucket = &kvm->mmu_page_hash[index];
842 hlist_for_each_entry_safe(page, node, n, bucket, hash_link)
843 if (page->gfn == gfn && !page->role.metaphysical) {
844 pgprintk("%s: gfn %lx role %x\n", __FUNCTION__, gfn,
845 page->role.word);
846 kvm_mmu_zap_page(kvm, page);
847 r = 1;
848 }
849 return r;
850 }
851
852 static void mmu_unshadow(struct kvm *kvm, gfn_t gfn)
853 {
854 struct kvm_mmu_page *page;
855
856 while ((page = kvm_mmu_lookup_page(kvm, gfn)) != NULL) {
857 pgprintk("%s: zap %lx %x\n",
858 __FUNCTION__, gfn, page->role.word);
859 kvm_mmu_zap_page(kvm, page);
860 }
861 }
862
863 static void page_header_update_slot(struct kvm *kvm, void *pte, gfn_t gfn)
864 {
865 int slot = memslot_id(kvm, gfn_to_memslot(kvm, gfn));
866 struct kvm_mmu_page *page_head = page_header(__pa(pte));
867
868 __set_bit(slot, &page_head->slot_bitmap);
869 }
870
871 hpa_t gpa_to_hpa(struct kvm *kvm, gpa_t gpa)
872 {
873 struct page *page;
874 hpa_t hpa;
875
876 ASSERT((gpa & HPA_ERR_MASK) == 0);
877 page = gfn_to_page(kvm, gpa >> PAGE_SHIFT);
878 hpa = ((hpa_t)page_to_pfn(page) << PAGE_SHIFT) | (gpa & (PAGE_SIZE-1));
879 if (is_error_page(page))
880 return hpa | HPA_ERR_MASK;
881 return hpa;
882 }
883
884 hpa_t gva_to_hpa(struct kvm_vcpu *vcpu, gva_t gva)
885 {
886 gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, gva);
887
888 if (gpa == UNMAPPED_GVA)
889 return UNMAPPED_GVA;
890 return gpa_to_hpa(vcpu->kvm, gpa);
891 }
892
893 struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva)
894 {
895 gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, gva);
896
897 if (gpa == UNMAPPED_GVA)
898 return NULL;
899 return pfn_to_page(gpa_to_hpa(vcpu->kvm, gpa) >> PAGE_SHIFT);
900 }
901
902 static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
903 {
904 }
905
906 static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, hpa_t p)
907 {
908 int level = PT32E_ROOT_LEVEL;
909 hpa_t table_addr = vcpu->mmu.root_hpa;
910 struct page *page;
911
912 page = pfn_to_page(p >> PAGE_SHIFT);
913 for (; ; level--) {
914 u32 index = PT64_INDEX(v, level);
915 u64 *table;
916 u64 pte;
917
918 ASSERT(VALID_PAGE(table_addr));
919 table = __va(table_addr);
920
921 if (level == 1) {
922 int was_rmapped;
923
924 pte = table[index];
925 was_rmapped = is_rmap_pte(pte);
926 if (is_shadow_present_pte(pte) && is_writeble_pte(pte)) {
927 kvm_release_page_clean(page);
928 return 0;
929 }
930 mark_page_dirty(vcpu->kvm, v >> PAGE_SHIFT);
931 page_header_update_slot(vcpu->kvm, table,
932 v >> PAGE_SHIFT);
933 table[index] = p | PT_PRESENT_MASK | PT_WRITABLE_MASK |
934 PT_USER_MASK;
935 if (!was_rmapped)
936 rmap_add(vcpu, &table[index], v >> PAGE_SHIFT);
937 else
938 kvm_release_page_clean(page);
939
940 return 0;
941 }
942
943 if (table[index] == shadow_trap_nonpresent_pte) {
944 struct kvm_mmu_page *new_table;
945 gfn_t pseudo_gfn;
946
947 pseudo_gfn = (v & PT64_DIR_BASE_ADDR_MASK)
948 >> PAGE_SHIFT;
949 new_table = kvm_mmu_get_page(vcpu, pseudo_gfn,
950 v, level - 1,
951 1, 3, &table[index]);
952 if (!new_table) {
953 pgprintk("nonpaging_map: ENOMEM\n");
954 kvm_release_page_clean(page);
955 return -ENOMEM;
956 }
957
958 table[index] = __pa(new_table->spt) | PT_PRESENT_MASK
959 | PT_WRITABLE_MASK | PT_USER_MASK;
960 }
961 table_addr = table[index] & PT64_BASE_ADDR_MASK;
962 }
963 }
964
965 static void nonpaging_prefetch_page(struct kvm_vcpu *vcpu,
966 struct kvm_mmu_page *sp)
967 {
968 int i;
969
970 for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
971 sp->spt[i] = shadow_trap_nonpresent_pte;
972 }
973
974 static void mmu_free_roots(struct kvm_vcpu *vcpu)
975 {
976 int i;
977 struct kvm_mmu_page *page;
978
979 if (!VALID_PAGE(vcpu->mmu.root_hpa))
980 return;
981 #ifdef CONFIG_X86_64
982 if (vcpu->mmu.shadow_root_level == PT64_ROOT_LEVEL) {
983 hpa_t root = vcpu->mmu.root_hpa;
984
985 page = page_header(root);
986 --page->root_count;
987 vcpu->mmu.root_hpa = INVALID_PAGE;
988 return;
989 }
990 #endif
991 for (i = 0; i < 4; ++i) {
992 hpa_t root = vcpu->mmu.pae_root[i];
993
994 if (root) {
995 root &= PT64_BASE_ADDR_MASK;
996 page = page_header(root);
997 --page->root_count;
998 }
999 vcpu->mmu.pae_root[i] = INVALID_PAGE;
1000 }
1001 vcpu->mmu.root_hpa = INVALID_PAGE;
1002 }
1003
1004 static void mmu_alloc_roots(struct kvm_vcpu *vcpu)
1005 {
1006 int i;
1007 gfn_t root_gfn;
1008 struct kvm_mmu_page *page;
1009
1010 root_gfn = vcpu->cr3 >> PAGE_SHIFT;
1011
1012 #ifdef CONFIG_X86_64
1013 if (vcpu->mmu.shadow_root_level == PT64_ROOT_LEVEL) {
1014 hpa_t root = vcpu->mmu.root_hpa;
1015
1016 ASSERT(!VALID_PAGE(root));
1017 page = kvm_mmu_get_page(vcpu, root_gfn, 0,
1018 PT64_ROOT_LEVEL, 0, 0, NULL);
1019 root = __pa(page->spt);
1020 ++page->root_count;
1021 vcpu->mmu.root_hpa = root;
1022 return;
1023 }
1024 #endif
1025 for (i = 0; i < 4; ++i) {
1026 hpa_t root = vcpu->mmu.pae_root[i];
1027
1028 ASSERT(!VALID_PAGE(root));
1029 if (vcpu->mmu.root_level == PT32E_ROOT_LEVEL) {
1030 if (!is_present_pte(vcpu->pdptrs[i])) {
1031 vcpu->mmu.pae_root[i] = 0;
1032 continue;
1033 }
1034 root_gfn = vcpu->pdptrs[i] >> PAGE_SHIFT;
1035 } else if (vcpu->mmu.root_level == 0)
1036 root_gfn = 0;
1037 page = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
1038 PT32_ROOT_LEVEL, !is_paging(vcpu),
1039 0, NULL);
1040 root = __pa(page->spt);
1041 ++page->root_count;
1042 vcpu->mmu.pae_root[i] = root | PT_PRESENT_MASK;
1043 }
1044 vcpu->mmu.root_hpa = __pa(vcpu->mmu.pae_root);
1045 }
1046
1047 static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr)
1048 {
1049 return vaddr;
1050 }
1051
1052 static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
1053 u32 error_code)
1054 {
1055 gpa_t addr = gva;
1056 hpa_t paddr;
1057 int r;
1058
1059 r = mmu_topup_memory_caches(vcpu);
1060 if (r)
1061 return r;
1062
1063 ASSERT(vcpu);
1064 ASSERT(VALID_PAGE(vcpu->mmu.root_hpa));
1065
1066
1067 paddr = gpa_to_hpa(vcpu->kvm, addr & PT64_BASE_ADDR_MASK);
1068
1069 if (is_error_hpa(paddr)) {
1070 kvm_release_page_clean(pfn_to_page((paddr & PT64_BASE_ADDR_MASK)
1071 >> PAGE_SHIFT));
1072 return 1;
1073 }
1074
1075 return nonpaging_map(vcpu, addr & PAGE_MASK, paddr);
1076 }
1077
1078 static void nonpaging_free(struct kvm_vcpu *vcpu)
1079 {
1080 mmu_free_roots(vcpu);
1081 }
1082
1083 static int nonpaging_init_context(struct kvm_vcpu *vcpu)
1084 {
1085 struct kvm_mmu *context = &vcpu->mmu;
1086
1087 context->new_cr3 = nonpaging_new_cr3;
1088 context->page_fault = nonpaging_page_fault;
1089 context->gva_to_gpa = nonpaging_gva_to_gpa;
1090 context->free = nonpaging_free;
1091 context->prefetch_page = nonpaging_prefetch_page;
1092 context->root_level = 0;
1093 context->shadow_root_level = PT32E_ROOT_LEVEL;
1094 context->root_hpa = INVALID_PAGE;
1095 return 0;
1096 }
1097
1098 void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
1099 {
1100 ++vcpu->stat.tlb_flush;
1101 kvm_x86_ops->tlb_flush(vcpu);
1102 }
1103
1104 static void paging_new_cr3(struct kvm_vcpu *vcpu)
1105 {
1106 pgprintk("%s: cr3 %lx\n", __FUNCTION__, vcpu->cr3);
1107 mmu_free_roots(vcpu);
1108 }
1109
1110 static void inject_page_fault(struct kvm_vcpu *vcpu,
1111 u64 addr,
1112 u32 err_code)
1113 {
1114 kvm_x86_ops->inject_page_fault(vcpu, addr, err_code);
1115 }
1116
1117 static void paging_free(struct kvm_vcpu *vcpu)
1118 {
1119 nonpaging_free(vcpu);
1120 }
1121
1122 #define PTTYPE 64
1123 #include "paging_tmpl.h"
1124 #undef PTTYPE
1125
1126 #define PTTYPE 32
1127 #include "paging_tmpl.h"
1128 #undef PTTYPE
1129
1130 static int paging64_init_context_common(struct kvm_vcpu *vcpu, int level)
1131 {
1132 struct kvm_mmu *context = &vcpu->mmu;
1133
1134 ASSERT(is_pae(vcpu));
1135 context->new_cr3 = paging_new_cr3;
1136 context->page_fault = paging64_page_fault;
1137 context->gva_to_gpa = paging64_gva_to_gpa;
1138 context->prefetch_page = paging64_prefetch_page;
1139 context->free = paging_free;
1140 context->root_level = level;
1141 context->shadow_root_level = level;
1142 context->root_hpa = INVALID_PAGE;
1143 return 0;
1144 }
1145
1146 static int paging64_init_context(struct kvm_vcpu *vcpu)
1147 {
1148 return paging64_init_context_common(vcpu, PT64_ROOT_LEVEL);
1149 }
1150
1151 static int paging32_init_context(struct kvm_vcpu *vcpu)
1152 {
1153 struct kvm_mmu *context = &vcpu->mmu;
1154
1155 context->new_cr3 = paging_new_cr3;
1156 context->page_fault = paging32_page_fault;
1157 context->gva_to_gpa = paging32_gva_to_gpa;
1158 context->free = paging_free;
1159 context->prefetch_page = paging32_prefetch_page;
1160 context->root_level = PT32_ROOT_LEVEL;
1161 context->shadow_root_level = PT32E_ROOT_LEVEL;
1162 context->root_hpa = INVALID_PAGE;
1163 return 0;
1164 }
1165
1166 static int paging32E_init_context(struct kvm_vcpu *vcpu)
1167 {
1168 return paging64_init_context_common(vcpu, PT32E_ROOT_LEVEL);
1169 }
1170
1171 static int init_kvm_mmu(struct kvm_vcpu *vcpu)
1172 {
1173 ASSERT(vcpu);
1174 ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));
1175
1176 if (!is_paging(vcpu))
1177 return nonpaging_init_context(vcpu);
1178 else if (is_long_mode(vcpu))
1179 return paging64_init_context(vcpu);
1180 else if (is_pae(vcpu))
1181 return paging32E_init_context(vcpu);
1182 else
1183 return paging32_init_context(vcpu);
1184 }
1185
1186 static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
1187 {
1188 ASSERT(vcpu);
1189 if (VALID_PAGE(vcpu->mmu.root_hpa)) {
1190 vcpu->mmu.free(vcpu);
1191 vcpu->mmu.root_hpa = INVALID_PAGE;
1192 }
1193 }
1194
1195 int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
1196 {
1197 destroy_kvm_mmu(vcpu);
1198 return init_kvm_mmu(vcpu);
1199 }
1200 EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
1201
1202 int kvm_mmu_load(struct kvm_vcpu *vcpu)
1203 {
1204 int r;
1205
1206 mutex_lock(&vcpu->kvm->lock);
1207 r = mmu_topup_memory_caches(vcpu);
1208 if (r)
1209 goto out;
1210 mmu_alloc_roots(vcpu);
1211 kvm_x86_ops->set_cr3(vcpu, vcpu->mmu.root_hpa);
1212 kvm_mmu_flush_tlb(vcpu);
1213 out:
1214 mutex_unlock(&vcpu->kvm->lock);
1215 return r;
1216 }
1217 EXPORT_SYMBOL_GPL(kvm_mmu_load);
1218
1219 void kvm_mmu_unload(struct kvm_vcpu *vcpu)
1220 {
1221 mmu_free_roots(vcpu);
1222 }
1223
1224 static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
1225 struct kvm_mmu_page *page,
1226 u64 *spte)
1227 {
1228 u64 pte;
1229 struct kvm_mmu_page *child;
1230
1231 pte = *spte;
1232 if (is_shadow_present_pte(pte)) {
1233 if (page->role.level == PT_PAGE_TABLE_LEVEL)
1234 rmap_remove(vcpu->kvm, spte);
1235 else {
1236 child = page_header(pte & PT64_BASE_ADDR_MASK);
1237 mmu_page_remove_parent_pte(child, spte);
1238 }
1239 }
1240 set_shadow_pte(spte, shadow_trap_nonpresent_pte);
1241 }
1242
1243 static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
1244 struct kvm_mmu_page *page,
1245 u64 *spte,
1246 const void *new, int bytes,
1247 int offset_in_pte)
1248 {
1249 if (page->role.level != PT_PAGE_TABLE_LEVEL) {
1250 ++vcpu->kvm->stat.mmu_pde_zapped;
1251 return;
1252 }
1253
1254 ++vcpu->kvm->stat.mmu_pte_updated;
1255 if (page->role.glevels == PT32_ROOT_LEVEL)
1256 paging32_update_pte(vcpu, page, spte, new, bytes,
1257 offset_in_pte);
1258 else
1259 paging64_update_pte(vcpu, page, spte, new, bytes,
1260 offset_in_pte);
1261 }
1262
1263 static bool need_remote_flush(u64 old, u64 new)
1264 {
1265 if (!is_shadow_present_pte(old))
1266 return false;
1267 if (!is_shadow_present_pte(new))
1268 return true;
1269 if ((old ^ new) & PT64_BASE_ADDR_MASK)
1270 return true;
1271 old ^= PT64_NX_MASK;
1272 new ^= PT64_NX_MASK;
1273 return (old & ~new & PT64_PERM_MASK) != 0;
1274 }
1275
1276 static void mmu_pte_write_flush_tlb(struct kvm_vcpu *vcpu, u64 old, u64 new)
1277 {
1278 if (need_remote_flush(old, new))
1279 kvm_flush_remote_tlbs(vcpu->kvm);
1280 else
1281 kvm_mmu_flush_tlb(vcpu);
1282 }
1283
1284 static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu)
1285 {
1286 u64 *spte = vcpu->last_pte_updated;
1287
1288 return !!(spte && (*spte & PT_ACCESSED_MASK));
1289 }
1290
1291 void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
1292 const u8 *new, int bytes)
1293 {
1294 gfn_t gfn = gpa >> PAGE_SHIFT;
1295 struct kvm_mmu_page *page;
1296 struct hlist_node *node, *n;
1297 struct hlist_head *bucket;
1298 unsigned index;
1299 u64 entry;
1300 u64 *spte;
1301 unsigned offset = offset_in_page(gpa);
1302 unsigned pte_size;
1303 unsigned page_offset;
1304 unsigned misaligned;
1305 unsigned quadrant;
1306 int level;
1307 int flooded = 0;
1308 int npte;
1309
1310 pgprintk("%s: gpa %llx bytes %d\n", __FUNCTION__, gpa, bytes);
1311 ++vcpu->kvm->stat.mmu_pte_write;
1312 kvm_mmu_audit(vcpu, "pre pte write");
1313 if (gfn == vcpu->last_pt_write_gfn
1314 && !last_updated_pte_accessed(vcpu)) {
1315 ++vcpu->last_pt_write_count;
1316 if (vcpu->last_pt_write_count >= 3)
1317 flooded = 1;
1318 } else {
1319 vcpu->last_pt_write_gfn = gfn;
1320 vcpu->last_pt_write_count = 1;
1321 vcpu->last_pte_updated = NULL;
1322 }
1323 index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
1324 bucket = &vcpu->kvm->mmu_page_hash[index];
1325 hlist_for_each_entry_safe(page, node, n, bucket, hash_link) {
1326 if (page->gfn != gfn || page->role.metaphysical)
1327 continue;
1328 pte_size = page->role.glevels == PT32_ROOT_LEVEL ? 4 : 8;
1329 misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
1330 misaligned |= bytes < 4;
1331 if (misaligned || flooded) {
1332 /*
1333 * Misaligned accesses are too much trouble to fix
1334 * up; also, they usually indicate a page is not used
1335 * as a page table.
1336 *
1337 * If we're seeing too many writes to a page,
1338 * it may no longer be a page table, or we may be
1339 * forking, in which case it is better to unmap the
1340 * page.
1341 */
1342 pgprintk("misaligned: gpa %llx bytes %d role %x\n",
1343 gpa, bytes, page->role.word);
1344 kvm_mmu_zap_page(vcpu->kvm, page);
1345 ++vcpu->kvm->stat.mmu_flooded;
1346 continue;
1347 }
1348 page_offset = offset;
1349 level = page->role.level;
1350 npte = 1;
1351 if (page->role.glevels == PT32_ROOT_LEVEL) {
1352 page_offset <<= 1; /* 32->64 */
1353 /*
1354 * A 32-bit pde maps 4MB while the shadow pdes map
1355 * only 2MB. So we need to double the offset again
1356 * and zap two pdes instead of one.
1357 */
1358 if (level == PT32_ROOT_LEVEL) {
1359 page_offset &= ~7; /* kill rounding error */
1360 page_offset <<= 1;
1361 npte = 2;
1362 }
1363 quadrant = page_offset >> PAGE_SHIFT;
1364 page_offset &= ~PAGE_MASK;
1365 if (quadrant != page->role.quadrant)
1366 continue;
1367 }
1368 spte = &page->spt[page_offset / sizeof(*spte)];
1369 while (npte--) {
1370 entry = *spte;
1371 mmu_pte_write_zap_pte(vcpu, page, spte);
1372 mmu_pte_write_new_pte(vcpu, page, spte, new, bytes,
1373 page_offset & (pte_size - 1));
1374 mmu_pte_write_flush_tlb(vcpu, entry, *spte);
1375 ++spte;
1376 }
1377 }
1378 kvm_mmu_audit(vcpu, "post pte write");
1379 }
1380
1381 int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
1382 {
1383 gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, gva);
1384
1385 return kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
1386 }
1387
1388 void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
1389 {
1390 while (vcpu->kvm->n_free_mmu_pages < KVM_REFILL_PAGES) {
1391 struct kvm_mmu_page *page;
1392
1393 page = container_of(vcpu->kvm->active_mmu_pages.prev,
1394 struct kvm_mmu_page, link);
1395 kvm_mmu_zap_page(vcpu->kvm, page);
1396 ++vcpu->kvm->stat.mmu_recycled;
1397 }
1398 }
1399
1400 int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code)
1401 {
1402 int r;
1403 enum emulation_result er;
1404
1405 mutex_lock(&vcpu->kvm->lock);
1406 r = vcpu->mmu.page_fault(vcpu, cr2, error_code);
1407 if (r < 0)
1408 goto out;
1409
1410 if (!r) {
1411 r = 1;
1412 goto out;
1413 }
1414
1415 r = mmu_topup_memory_caches(vcpu);
1416 if (r)
1417 goto out;
1418
1419 er = emulate_instruction(vcpu, vcpu->run, cr2, error_code, 0);
1420 mutex_unlock(&vcpu->kvm->lock);
1421
1422 switch (er) {
1423 case EMULATE_DONE:
1424 return 1;
1425 case EMULATE_DO_MMIO:
1426 ++vcpu->stat.mmio_exits;
1427 return 0;
1428 case EMULATE_FAIL:
1429 kvm_report_emulation_failure(vcpu, "pagetable");
1430 return 1;
1431 default:
1432 BUG();
1433 }
1434 out:
1435 mutex_unlock(&vcpu->kvm->lock);
1436 return r;
1437 }
1438 EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);
1439
1440 static void free_mmu_pages(struct kvm_vcpu *vcpu)
1441 {
1442 struct kvm_mmu_page *page;
1443
1444 while (!list_empty(&vcpu->kvm->active_mmu_pages)) {
1445 page = container_of(vcpu->kvm->active_mmu_pages.next,
1446 struct kvm_mmu_page, link);
1447 kvm_mmu_zap_page(vcpu->kvm, page);
1448 }
1449 free_page((unsigned long)vcpu->mmu.pae_root);
1450 }
1451
1452 static int alloc_mmu_pages(struct kvm_vcpu *vcpu)
1453 {
1454 struct page *page;
1455 int i;
1456
1457 ASSERT(vcpu);
1458
1459 if (vcpu->kvm->n_requested_mmu_pages)
1460 vcpu->kvm->n_free_mmu_pages = vcpu->kvm->n_requested_mmu_pages;
1461 else
1462 vcpu->kvm->n_free_mmu_pages = vcpu->kvm->n_alloc_mmu_pages;
1463 /*
1464 * When emulating 32-bit mode, cr3 is only 32 bits even on x86_64.
1465 * Therefore we need to allocate shadow page tables in the first
1466 * 4GB of memory, which happens to fit the DMA32 zone.
1467 */
1468 page = alloc_page(GFP_KERNEL | __GFP_DMA32);
1469 if (!page)
1470 goto error_1;
1471 vcpu->mmu.pae_root = page_address(page);
1472 for (i = 0; i < 4; ++i)
1473 vcpu->mmu.pae_root[i] = INVALID_PAGE;
1474
1475 return 0;
1476
1477 error_1:
1478 free_mmu_pages(vcpu);
1479 return -ENOMEM;
1480 }
1481
1482 int kvm_mmu_create(struct kvm_vcpu *vcpu)
1483 {
1484 ASSERT(vcpu);
1485 ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));
1486
1487 return alloc_mmu_pages(vcpu);
1488 }
1489
1490 int kvm_mmu_setup(struct kvm_vcpu *vcpu)
1491 {
1492 ASSERT(vcpu);
1493 ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));
1494
1495 return init_kvm_mmu(vcpu);
1496 }
1497
1498 void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
1499 {
1500 ASSERT(vcpu);
1501
1502 destroy_kvm_mmu(vcpu);
1503 free_mmu_pages(vcpu);
1504 mmu_free_memory_caches(vcpu);
1505 }
1506
1507 void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
1508 {
1509 struct kvm_mmu_page *page;
1510
1511 list_for_each_entry(page, &kvm->active_mmu_pages, link) {
1512 int i;
1513 u64 *pt;
1514
1515 if (!test_bit(slot, &page->slot_bitmap))
1516 continue;
1517
1518 pt = page->spt;
1519 for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
1520 /* avoid RMW */
1521 if (pt[i] & PT_WRITABLE_MASK)
1522 pt[i] &= ~PT_WRITABLE_MASK;
1523 }
1524 }
1525
1526 void kvm_mmu_zap_all(struct kvm *kvm)
1527 {
1528 struct kvm_mmu_page *page, *node;
1529
1530 list_for_each_entry_safe(page, node, &kvm->active_mmu_pages, link)
1531 kvm_mmu_zap_page(kvm, page);
1532
1533 kvm_flush_remote_tlbs(kvm);
1534 }
1535
1536 void kvm_mmu_module_exit(void)
1537 {
1538 if (pte_chain_cache)
1539 kmem_cache_destroy(pte_chain_cache);
1540 if (rmap_desc_cache)
1541 kmem_cache_destroy(rmap_desc_cache);
1542 if (mmu_page_header_cache)
1543 kmem_cache_destroy(mmu_page_header_cache);
1544 }
1545
1546 int kvm_mmu_module_init(void)
1547 {
1548 pte_chain_cache = kmem_cache_create("kvm_pte_chain",
1549 sizeof(struct kvm_pte_chain),
1550 0, 0, NULL);
1551 if (!pte_chain_cache)
1552 goto nomem;
1553 rmap_desc_cache = kmem_cache_create("kvm_rmap_desc",
1554 sizeof(struct kvm_rmap_desc),
1555 0, 0, NULL);
1556 if (!rmap_desc_cache)
1557 goto nomem;
1558
1559 mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
1560 sizeof(struct kvm_mmu_page),
1561 0, 0, NULL);
1562 if (!mmu_page_header_cache)
1563 goto nomem;
1564
1565 return 0;
1566
1567 nomem:
1568 kvm_mmu_module_exit();
1569 return -ENOMEM;
1570 }
1571
1572 /*
1573 * Caculate mmu pages needed for kvm.
1574 */
1575 unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
1576 {
1577 int i;
1578 unsigned int nr_mmu_pages;
1579 unsigned int nr_pages = 0;
1580
1581 for (i = 0; i < kvm->nmemslots; i++)
1582 nr_pages += kvm->memslots[i].npages;
1583
1584 nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000;
1585 nr_mmu_pages = max(nr_mmu_pages,
1586 (unsigned int) KVM_MIN_ALLOC_MMU_PAGES);
1587
1588 return nr_mmu_pages;
1589 }
1590
1591 #ifdef AUDIT
1592
1593 static const char *audit_msg;
1594
1595 static gva_t canonicalize(gva_t gva)
1596 {
1597 #ifdef CONFIG_X86_64
1598 gva = (long long)(gva << 16) >> 16;
1599 #endif
1600 return gva;
1601 }
1602
1603 static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
1604 gva_t va, int level)
1605 {
1606 u64 *pt = __va(page_pte & PT64_BASE_ADDR_MASK);
1607 int i;
1608 gva_t va_delta = 1ul << (PAGE_SHIFT + 9 * (level - 1));
1609
1610 for (i = 0; i < PT64_ENT_PER_PAGE; ++i, va += va_delta) {
1611 u64 ent = pt[i];
1612
1613 if (ent == shadow_trap_nonpresent_pte)
1614 continue;
1615
1616 va = canonicalize(va);
1617 if (level > 1) {
1618 if (ent == shadow_notrap_nonpresent_pte)
1619 printk(KERN_ERR "audit: (%s) nontrapping pte"
1620 " in nonleaf level: levels %d gva %lx"
1621 " level %d pte %llx\n", audit_msg,
1622 vcpu->mmu.root_level, va, level, ent);
1623
1624 audit_mappings_page(vcpu, ent, va, level - 1);
1625 } else {
1626 gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, va);
1627 hpa_t hpa = gpa_to_hpa(vcpu, gpa);
1628 struct page *page;
1629
1630 if (is_shadow_present_pte(ent)
1631 && (ent & PT64_BASE_ADDR_MASK) != hpa)
1632 printk(KERN_ERR "xx audit error: (%s) levels %d"
1633 " gva %lx gpa %llx hpa %llx ent %llx %d\n",
1634 audit_msg, vcpu->mmu.root_level,
1635 va, gpa, hpa, ent,
1636 is_shadow_present_pte(ent));
1637 else if (ent == shadow_notrap_nonpresent_pte
1638 && !is_error_hpa(hpa))
1639 printk(KERN_ERR "audit: (%s) notrap shadow,"
1640 " valid guest gva %lx\n", audit_msg, va);
1641 page = pfn_to_page((gpa & PT64_BASE_ADDR_MASK)
1642 >> PAGE_SHIFT);
1643 kvm_release_page_clean(page);
1644
1645 }
1646 }
1647 }
1648
1649 static void audit_mappings(struct kvm_vcpu *vcpu)
1650 {
1651 unsigned i;
1652
1653 if (vcpu->mmu.root_level == 4)
1654 audit_mappings_page(vcpu, vcpu->mmu.root_hpa, 0, 4);
1655 else
1656 for (i = 0; i < 4; ++i)
1657 if (vcpu->mmu.pae_root[i] & PT_PRESENT_MASK)
1658 audit_mappings_page(vcpu,
1659 vcpu->mmu.pae_root[i],
1660 i << 30,
1661 2);
1662 }
1663
1664 static int count_rmaps(struct kvm_vcpu *vcpu)
1665 {
1666 int nmaps = 0;
1667 int i, j, k;
1668
1669 for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
1670 struct kvm_memory_slot *m = &vcpu->kvm->memslots[i];
1671 struct kvm_rmap_desc *d;
1672
1673 for (j = 0; j < m->npages; ++j) {
1674 unsigned long *rmapp = &m->rmap[j];
1675
1676 if (!*rmapp)
1677 continue;
1678 if (!(*rmapp & 1)) {
1679 ++nmaps;
1680 continue;
1681 }
1682 d = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
1683 while (d) {
1684 for (k = 0; k < RMAP_EXT; ++k)
1685 if (d->shadow_ptes[k])
1686 ++nmaps;
1687 else
1688 break;
1689 d = d->more;
1690 }
1691 }
1692 }
1693 return nmaps;
1694 }
1695
1696 static int count_writable_mappings(struct kvm_vcpu *vcpu)
1697 {
1698 int nmaps = 0;
1699 struct kvm_mmu_page *page;
1700 int i;
1701
1702 list_for_each_entry(page, &vcpu->kvm->active_mmu_pages, link) {
1703 u64 *pt = page->spt;
1704
1705 if (page->role.level != PT_PAGE_TABLE_LEVEL)
1706 continue;
1707
1708 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
1709 u64 ent = pt[i];
1710
1711 if (!(ent & PT_PRESENT_MASK))
1712 continue;
1713 if (!(ent & PT_WRITABLE_MASK))
1714 continue;
1715 ++nmaps;
1716 }
1717 }
1718 return nmaps;
1719 }
1720
1721 static void audit_rmap(struct kvm_vcpu *vcpu)
1722 {
1723 int n_rmap = count_rmaps(vcpu);
1724 int n_actual = count_writable_mappings(vcpu);
1725
1726 if (n_rmap != n_actual)
1727 printk(KERN_ERR "%s: (%s) rmap %d actual %d\n",
1728 __FUNCTION__, audit_msg, n_rmap, n_actual);
1729 }
1730
1731 static void audit_write_protection(struct kvm_vcpu *vcpu)
1732 {
1733 struct kvm_mmu_page *page;
1734 struct kvm_memory_slot *slot;
1735 unsigned long *rmapp;
1736 gfn_t gfn;
1737
1738 list_for_each_entry(page, &vcpu->kvm->active_mmu_pages, link) {
1739 if (page->role.metaphysical)
1740 continue;
1741
1742 slot = gfn_to_memslot(vcpu->kvm, page->gfn);
1743 gfn = unalias_gfn(vcpu->kvm, page->gfn);
1744 rmapp = &slot->rmap[gfn - slot->base_gfn];
1745 if (*rmapp)
1746 printk(KERN_ERR "%s: (%s) shadow page has writable"
1747 " mappings: gfn %lx role %x\n",
1748 __FUNCTION__, audit_msg, page->gfn,
1749 page->role.word);
1750 }
1751 }
1752
1753 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg)
1754 {
1755 int olddbg = dbg;
1756
1757 dbg = 0;
1758 audit_msg = msg;
1759 audit_rmap(vcpu);
1760 audit_write_protection(vcpu);
1761 audit_mappings(vcpu);
1762 dbg = olddbg;
1763 }
1764
1765 #endif
Linux kernel - Deliverables
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