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