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Merge branch 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm
[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
23 #include <linux/types.h>
24 #include <linux/string.h>
25 #include <linux/mm.h>
26 #include <linux/highmem.h>
27 #include <linux/module.h>
28
29 #include <asm/page.h>
30 #include <asm/cmpxchg.h>
31
32 #undef MMU_DEBUG
33
34 #undef AUDIT
35
36 #ifdef AUDIT
37 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg);
38 #else
39 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg) {}
40 #endif
41
42 #ifdef MMU_DEBUG
43
44 #define pgprintk(x...) do { if (dbg) printk(x); } while (0)
45 #define rmap_printk(x...) do { if (dbg) printk(x); } while (0)
46
47 #else
48
49 #define pgprintk(x...) do { } while (0)
50 #define rmap_printk(x...) do { } while (0)
51
52 #endif
53
54 #if defined(MMU_DEBUG) || defined(AUDIT)
55 static int dbg = 1;
56 #endif
57
58 #ifndef MMU_DEBUG
59 #define ASSERT(x) do { } while (0)
60 #else
61 #define ASSERT(x) \
62 if (!(x)) { \
63 printk(KERN_WARNING "assertion failed %s:%d: %s\n", \
64 __FILE__, __LINE__, #x); \
65 }
66 #endif
67
68 #define PT64_PT_BITS 9
69 #define PT64_ENT_PER_PAGE (1 << PT64_PT_BITS)
70 #define PT32_PT_BITS 10
71 #define PT32_ENT_PER_PAGE (1 << PT32_PT_BITS)
72
73 #define PT_WRITABLE_SHIFT 1
74
75 #define PT_PRESENT_MASK (1ULL << 0)
76 #define PT_WRITABLE_MASK (1ULL << PT_WRITABLE_SHIFT)
77 #define PT_USER_MASK (1ULL << 2)
78 #define PT_PWT_MASK (1ULL << 3)
79 #define PT_PCD_MASK (1ULL << 4)
80 #define PT_ACCESSED_MASK (1ULL << 5)
81 #define PT_DIRTY_MASK (1ULL << 6)
82 #define PT_PAGE_SIZE_MASK (1ULL << 7)
83 #define PT_PAT_MASK (1ULL << 7)
84 #define PT_GLOBAL_MASK (1ULL << 8)
85 #define PT64_NX_MASK (1ULL << 63)
86
87 #define PT_PAT_SHIFT 7
88 #define PT_DIR_PAT_SHIFT 12
89 #define PT_DIR_PAT_MASK (1ULL << PT_DIR_PAT_SHIFT)
90
91 #define PT32_DIR_PSE36_SIZE 4
92 #define PT32_DIR_PSE36_SHIFT 13
93 #define PT32_DIR_PSE36_MASK (((1ULL << PT32_DIR_PSE36_SIZE) - 1) << PT32_DIR_PSE36_SHIFT)
94
95
96 #define PT_FIRST_AVAIL_BITS_SHIFT 9
97 #define PT64_SECOND_AVAIL_BITS_SHIFT 52
98
99 #define PT_SHADOW_IO_MARK (1ULL << PT_FIRST_AVAIL_BITS_SHIFT)
100
101 #define VALID_PAGE(x) ((x) != INVALID_PAGE)
102
103 #define PT64_LEVEL_BITS 9
104
105 #define PT64_LEVEL_SHIFT(level) \
106 ( PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS )
107
108 #define PT64_LEVEL_MASK(level) \
109 (((1ULL << PT64_LEVEL_BITS) - 1) << PT64_LEVEL_SHIFT(level))
110
111 #define PT64_INDEX(address, level)\
112 (((address) >> PT64_LEVEL_SHIFT(level)) & ((1 << PT64_LEVEL_BITS) - 1))
113
114
115 #define PT32_LEVEL_BITS 10
116
117 #define PT32_LEVEL_SHIFT(level) \
118 ( PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS )
119
120 #define PT32_LEVEL_MASK(level) \
121 (((1ULL << PT32_LEVEL_BITS) - 1) << PT32_LEVEL_SHIFT(level))
122
123 #define PT32_INDEX(address, level)\
124 (((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))
125
126
127 #define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))
128 #define PT64_DIR_BASE_ADDR_MASK \
129 (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))
130
131 #define PT32_BASE_ADDR_MASK PAGE_MASK
132 #define PT32_DIR_BASE_ADDR_MASK \
133 (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
134
135
136 #define PFERR_PRESENT_MASK (1U << 0)
137 #define PFERR_WRITE_MASK (1U << 1)
138 #define PFERR_USER_MASK (1U << 2)
139 #define PFERR_FETCH_MASK (1U << 4)
140
141 #define PT64_ROOT_LEVEL 4
142 #define PT32_ROOT_LEVEL 2
143 #define PT32E_ROOT_LEVEL 3
144
145 #define PT_DIRECTORY_LEVEL 2
146 #define PT_PAGE_TABLE_LEVEL 1
147
148 #define RMAP_EXT 4
149
150 struct kvm_rmap_desc {
151 u64 *shadow_ptes[RMAP_EXT];
152 struct kvm_rmap_desc *more;
153 };
154
155 static struct kmem_cache *pte_chain_cache;
156 static struct kmem_cache *rmap_desc_cache;
157 static struct kmem_cache *mmu_page_header_cache;
158
159 static int is_write_protection(struct kvm_vcpu *vcpu)
160 {
161 return vcpu->cr0 & CR0_WP_MASK;
162 }
163
164 static int is_cpuid_PSE36(void)
165 {
166 return 1;
167 }
168
169 static int is_nx(struct kvm_vcpu *vcpu)
170 {
171 return vcpu->shadow_efer & EFER_NX;
172 }
173
174 static int is_present_pte(unsigned long pte)
175 {
176 return pte & PT_PRESENT_MASK;
177 }
178
179 static int is_writeble_pte(unsigned long pte)
180 {
181 return pte & PT_WRITABLE_MASK;
182 }
183
184 static int is_io_pte(unsigned long pte)
185 {
186 return pte & PT_SHADOW_IO_MARK;
187 }
188
189 static int is_rmap_pte(u64 pte)
190 {
191 return (pte & (PT_WRITABLE_MASK | PT_PRESENT_MASK))
192 == (PT_WRITABLE_MASK | PT_PRESENT_MASK);
193 }
194
195 static void set_shadow_pte(u64 *sptep, u64 spte)
196 {
197 #ifdef CONFIG_X86_64
198 set_64bit((unsigned long *)sptep, spte);
199 #else
200 set_64bit((unsigned long long *)sptep, spte);
201 #endif
202 }
203
204 static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
205 struct kmem_cache *base_cache, int min,
206 gfp_t gfp_flags)
207 {
208 void *obj;
209
210 if (cache->nobjs >= min)
211 return 0;
212 while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
213 obj = kmem_cache_zalloc(base_cache, gfp_flags);
214 if (!obj)
215 return -ENOMEM;
216 cache->objects[cache->nobjs++] = obj;
217 }
218 return 0;
219 }
220
221 static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
222 {
223 while (mc->nobjs)
224 kfree(mc->objects[--mc->nobjs]);
225 }
226
227 static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
228 int min, gfp_t gfp_flags)
229 {
230 struct page *page;
231
232 if (cache->nobjs >= min)
233 return 0;
234 while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
235 page = alloc_page(gfp_flags);
236 if (!page)
237 return -ENOMEM;
238 set_page_private(page, 0);
239 cache->objects[cache->nobjs++] = page_address(page);
240 }
241 return 0;
242 }
243
244 static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
245 {
246 while (mc->nobjs)
247 free_page((unsigned long)mc->objects[--mc->nobjs]);
248 }
249
250 static int __mmu_topup_memory_caches(struct kvm_vcpu *vcpu, gfp_t gfp_flags)
251 {
252 int r;
253
254 r = mmu_topup_memory_cache(&vcpu->mmu_pte_chain_cache,
255 pte_chain_cache, 4, gfp_flags);
256 if (r)
257 goto out;
258 r = mmu_topup_memory_cache(&vcpu->mmu_rmap_desc_cache,
259 rmap_desc_cache, 1, gfp_flags);
260 if (r)
261 goto out;
262 r = mmu_topup_memory_cache_page(&vcpu->mmu_page_cache, 4, gfp_flags);
263 if (r)
264 goto out;
265 r = mmu_topup_memory_cache(&vcpu->mmu_page_header_cache,
266 mmu_page_header_cache, 4, gfp_flags);
267 out:
268 return r;
269 }
270
271 static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
272 {
273 int r;
274
275 r = __mmu_topup_memory_caches(vcpu, GFP_NOWAIT);
276 if (r < 0) {
277 spin_unlock(&vcpu->kvm->lock);
278 kvm_arch_ops->vcpu_put(vcpu);
279 r = __mmu_topup_memory_caches(vcpu, GFP_KERNEL);
280 kvm_arch_ops->vcpu_load(vcpu);
281 spin_lock(&vcpu->kvm->lock);
282 }
283 return r;
284 }
285
286 static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
287 {
288 mmu_free_memory_cache(&vcpu->mmu_pte_chain_cache);
289 mmu_free_memory_cache(&vcpu->mmu_rmap_desc_cache);
290 mmu_free_memory_cache_page(&vcpu->mmu_page_cache);
291 mmu_free_memory_cache(&vcpu->mmu_page_header_cache);
292 }
293
294 static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc,
295 size_t size)
296 {
297 void *p;
298
299 BUG_ON(!mc->nobjs);
300 p = mc->objects[--mc->nobjs];
301 memset(p, 0, size);
302 return p;
303 }
304
305 static struct kvm_pte_chain *mmu_alloc_pte_chain(struct kvm_vcpu *vcpu)
306 {
307 return mmu_memory_cache_alloc(&vcpu->mmu_pte_chain_cache,
308 sizeof(struct kvm_pte_chain));
309 }
310
311 static void mmu_free_pte_chain(struct kvm_pte_chain *pc)
312 {
313 kfree(pc);
314 }
315
316 static struct kvm_rmap_desc *mmu_alloc_rmap_desc(struct kvm_vcpu *vcpu)
317 {
318 return mmu_memory_cache_alloc(&vcpu->mmu_rmap_desc_cache,
319 sizeof(struct kvm_rmap_desc));
320 }
321
322 static void mmu_free_rmap_desc(struct kvm_rmap_desc *rd)
323 {
324 kfree(rd);
325 }
326
327 /*
328 * Reverse mapping data structures:
329 *
330 * If page->private bit zero is zero, then page->private points to the
331 * shadow page table entry that points to page_address(page).
332 *
333 * If page->private bit zero is one, (then page->private & ~1) points
334 * to a struct kvm_rmap_desc containing more mappings.
335 */
336 static void rmap_add(struct kvm_vcpu *vcpu, u64 *spte)
337 {
338 struct page *page;
339 struct kvm_rmap_desc *desc;
340 int i;
341
342 if (!is_rmap_pte(*spte))
343 return;
344 page = pfn_to_page((*spte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT);
345 if (!page_private(page)) {
346 rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte);
347 set_page_private(page,(unsigned long)spte);
348 } else if (!(page_private(page) & 1)) {
349 rmap_printk("rmap_add: %p %llx 1->many\n", spte, *spte);
350 desc = mmu_alloc_rmap_desc(vcpu);
351 desc->shadow_ptes[0] = (u64 *)page_private(page);
352 desc->shadow_ptes[1] = spte;
353 set_page_private(page,(unsigned long)desc | 1);
354 } else {
355 rmap_printk("rmap_add: %p %llx many->many\n", spte, *spte);
356 desc = (struct kvm_rmap_desc *)(page_private(page) & ~1ul);
357 while (desc->shadow_ptes[RMAP_EXT-1] && desc->more)
358 desc = desc->more;
359 if (desc->shadow_ptes[RMAP_EXT-1]) {
360 desc->more = mmu_alloc_rmap_desc(vcpu);
361 desc = desc->more;
362 }
363 for (i = 0; desc->shadow_ptes[i]; ++i)
364 ;
365 desc->shadow_ptes[i] = spte;
366 }
367 }
368
369 static void rmap_desc_remove_entry(struct page *page,
370 struct kvm_rmap_desc *desc,
371 int i,
372 struct kvm_rmap_desc *prev_desc)
373 {
374 int j;
375
376 for (j = RMAP_EXT - 1; !desc->shadow_ptes[j] && j > i; --j)
377 ;
378 desc->shadow_ptes[i] = desc->shadow_ptes[j];
379 desc->shadow_ptes[j] = NULL;
380 if (j != 0)
381 return;
382 if (!prev_desc && !desc->more)
383 set_page_private(page,(unsigned long)desc->shadow_ptes[0]);
384 else
385 if (prev_desc)
386 prev_desc->more = desc->more;
387 else
388 set_page_private(page,(unsigned long)desc->more | 1);
389 mmu_free_rmap_desc(desc);
390 }
391
392 static void rmap_remove(u64 *spte)
393 {
394 struct page *page;
395 struct kvm_rmap_desc *desc;
396 struct kvm_rmap_desc *prev_desc;
397 int i;
398
399 if (!is_rmap_pte(*spte))
400 return;
401 page = pfn_to_page((*spte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT);
402 if (!page_private(page)) {
403 printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte);
404 BUG();
405 } else if (!(page_private(page) & 1)) {
406 rmap_printk("rmap_remove: %p %llx 1->0\n", spte, *spte);
407 if ((u64 *)page_private(page) != spte) {
408 printk(KERN_ERR "rmap_remove: %p %llx 1->BUG\n",
409 spte, *spte);
410 BUG();
411 }
412 set_page_private(page,0);
413 } else {
414 rmap_printk("rmap_remove: %p %llx many->many\n", spte, *spte);
415 desc = (struct kvm_rmap_desc *)(page_private(page) & ~1ul);
416 prev_desc = NULL;
417 while (desc) {
418 for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i)
419 if (desc->shadow_ptes[i] == spte) {
420 rmap_desc_remove_entry(page,
421 desc, i,
422 prev_desc);
423 return;
424 }
425 prev_desc = desc;
426 desc = desc->more;
427 }
428 BUG();
429 }
430 }
431
432 static void rmap_write_protect(struct kvm_vcpu *vcpu, u64 gfn)
433 {
434 struct kvm *kvm = vcpu->kvm;
435 struct page *page;
436 struct kvm_rmap_desc *desc;
437 u64 *spte;
438
439 page = gfn_to_page(kvm, gfn);
440 BUG_ON(!page);
441
442 while (page_private(page)) {
443 if (!(page_private(page) & 1))
444 spte = (u64 *)page_private(page);
445 else {
446 desc = (struct kvm_rmap_desc *)(page_private(page) & ~1ul);
447 spte = desc->shadow_ptes[0];
448 }
449 BUG_ON(!spte);
450 BUG_ON((*spte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT
451 != page_to_pfn(page));
452 BUG_ON(!(*spte & PT_PRESENT_MASK));
453 BUG_ON(!(*spte & PT_WRITABLE_MASK));
454 rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
455 rmap_remove(spte);
456 set_shadow_pte(spte, *spte & ~PT_WRITABLE_MASK);
457 kvm_flush_remote_tlbs(vcpu->kvm);
458 }
459 }
460
461 #ifdef MMU_DEBUG
462 static int is_empty_shadow_page(u64 *spt)
463 {
464 u64 *pos;
465 u64 *end;
466
467 for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
468 if (*pos != 0) {
469 printk(KERN_ERR "%s: %p %llx\n", __FUNCTION__,
470 pos, *pos);
471 return 0;
472 }
473 return 1;
474 }
475 #endif
476
477 static void kvm_mmu_free_page(struct kvm *kvm,
478 struct kvm_mmu_page *page_head)
479 {
480 ASSERT(is_empty_shadow_page(page_head->spt));
481 list_del(&page_head->link);
482 __free_page(virt_to_page(page_head->spt));
483 kfree(page_head);
484 ++kvm->n_free_mmu_pages;
485 }
486
487 static unsigned kvm_page_table_hashfn(gfn_t gfn)
488 {
489 return gfn;
490 }
491
492 static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
493 u64 *parent_pte)
494 {
495 struct kvm_mmu_page *page;
496
497 if (!vcpu->kvm->n_free_mmu_pages)
498 return NULL;
499
500 page = mmu_memory_cache_alloc(&vcpu->mmu_page_header_cache,
501 sizeof *page);
502 page->spt = mmu_memory_cache_alloc(&vcpu->mmu_page_cache, PAGE_SIZE);
503 set_page_private(virt_to_page(page->spt), (unsigned long)page);
504 list_add(&page->link, &vcpu->kvm->active_mmu_pages);
505 ASSERT(is_empty_shadow_page(page->spt));
506 page->slot_bitmap = 0;
507 page->multimapped = 0;
508 page->parent_pte = parent_pte;
509 --vcpu->kvm->n_free_mmu_pages;
510 return page;
511 }
512
513 static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
514 struct kvm_mmu_page *page, u64 *parent_pte)
515 {
516 struct kvm_pte_chain *pte_chain;
517 struct hlist_node *node;
518 int i;
519
520 if (!parent_pte)
521 return;
522 if (!page->multimapped) {
523 u64 *old = page->parent_pte;
524
525 if (!old) {
526 page->parent_pte = parent_pte;
527 return;
528 }
529 page->multimapped = 1;
530 pte_chain = mmu_alloc_pte_chain(vcpu);
531 INIT_HLIST_HEAD(&page->parent_ptes);
532 hlist_add_head(&pte_chain->link, &page->parent_ptes);
533 pte_chain->parent_ptes[0] = old;
534 }
535 hlist_for_each_entry(pte_chain, node, &page->parent_ptes, link) {
536 if (pte_chain->parent_ptes[NR_PTE_CHAIN_ENTRIES-1])
537 continue;
538 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i)
539 if (!pte_chain->parent_ptes[i]) {
540 pte_chain->parent_ptes[i] = parent_pte;
541 return;
542 }
543 }
544 pte_chain = mmu_alloc_pte_chain(vcpu);
545 BUG_ON(!pte_chain);
546 hlist_add_head(&pte_chain->link, &page->parent_ptes);
547 pte_chain->parent_ptes[0] = parent_pte;
548 }
549
550 static void mmu_page_remove_parent_pte(struct kvm_mmu_page *page,
551 u64 *parent_pte)
552 {
553 struct kvm_pte_chain *pte_chain;
554 struct hlist_node *node;
555 int i;
556
557 if (!page->multimapped) {
558 BUG_ON(page->parent_pte != parent_pte);
559 page->parent_pte = NULL;
560 return;
561 }
562 hlist_for_each_entry(pte_chain, node, &page->parent_ptes, link)
563 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
564 if (!pte_chain->parent_ptes[i])
565 break;
566 if (pte_chain->parent_ptes[i] != parent_pte)
567 continue;
568 while (i + 1 < NR_PTE_CHAIN_ENTRIES
569 && pte_chain->parent_ptes[i + 1]) {
570 pte_chain->parent_ptes[i]
571 = pte_chain->parent_ptes[i + 1];
572 ++i;
573 }
574 pte_chain->parent_ptes[i] = NULL;
575 if (i == 0) {
576 hlist_del(&pte_chain->link);
577 mmu_free_pte_chain(pte_chain);
578 if (hlist_empty(&page->parent_ptes)) {
579 page->multimapped = 0;
580 page->parent_pte = NULL;
581 }
582 }
583 return;
584 }
585 BUG();
586 }
587
588 static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm_vcpu *vcpu,
589 gfn_t gfn)
590 {
591 unsigned index;
592 struct hlist_head *bucket;
593 struct kvm_mmu_page *page;
594 struct hlist_node *node;
595
596 pgprintk("%s: looking for gfn %lx\n", __FUNCTION__, gfn);
597 index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
598 bucket = &vcpu->kvm->mmu_page_hash[index];
599 hlist_for_each_entry(page, node, bucket, hash_link)
600 if (page->gfn == gfn && !page->role.metaphysical) {
601 pgprintk("%s: found role %x\n",
602 __FUNCTION__, page->role.word);
603 return page;
604 }
605 return NULL;
606 }
607
608 static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
609 gfn_t gfn,
610 gva_t gaddr,
611 unsigned level,
612 int metaphysical,
613 unsigned hugepage_access,
614 u64 *parent_pte)
615 {
616 union kvm_mmu_page_role role;
617 unsigned index;
618 unsigned quadrant;
619 struct hlist_head *bucket;
620 struct kvm_mmu_page *page;
621 struct hlist_node *node;
622
623 role.word = 0;
624 role.glevels = vcpu->mmu.root_level;
625 role.level = level;
626 role.metaphysical = metaphysical;
627 role.hugepage_access = hugepage_access;
628 if (vcpu->mmu.root_level <= PT32_ROOT_LEVEL) {
629 quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
630 quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
631 role.quadrant = quadrant;
632 }
633 pgprintk("%s: looking gfn %lx role %x\n", __FUNCTION__,
634 gfn, role.word);
635 index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
636 bucket = &vcpu->kvm->mmu_page_hash[index];
637 hlist_for_each_entry(page, node, bucket, hash_link)
638 if (page->gfn == gfn && page->role.word == role.word) {
639 mmu_page_add_parent_pte(vcpu, page, parent_pte);
640 pgprintk("%s: found\n", __FUNCTION__);
641 return page;
642 }
643 page = kvm_mmu_alloc_page(vcpu, parent_pte);
644 if (!page)
645 return page;
646 pgprintk("%s: adding gfn %lx role %x\n", __FUNCTION__, gfn, role.word);
647 page->gfn = gfn;
648 page->role = role;
649 hlist_add_head(&page->hash_link, bucket);
650 if (!metaphysical)
651 rmap_write_protect(vcpu, gfn);
652 return page;
653 }
654
655 static void kvm_mmu_page_unlink_children(struct kvm *kvm,
656 struct kvm_mmu_page *page)
657 {
658 unsigned i;
659 u64 *pt;
660 u64 ent;
661
662 pt = page->spt;
663
664 if (page->role.level == PT_PAGE_TABLE_LEVEL) {
665 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
666 if (pt[i] & PT_PRESENT_MASK)
667 rmap_remove(&pt[i]);
668 pt[i] = 0;
669 }
670 kvm_flush_remote_tlbs(kvm);
671 return;
672 }
673
674 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
675 ent = pt[i];
676
677 pt[i] = 0;
678 if (!(ent & PT_PRESENT_MASK))
679 continue;
680 ent &= PT64_BASE_ADDR_MASK;
681 mmu_page_remove_parent_pte(page_header(ent), &pt[i]);
682 }
683 kvm_flush_remote_tlbs(kvm);
684 }
685
686 static void kvm_mmu_put_page(struct kvm_mmu_page *page,
687 u64 *parent_pte)
688 {
689 mmu_page_remove_parent_pte(page, parent_pte);
690 }
691
692 static void kvm_mmu_zap_page(struct kvm *kvm,
693 struct kvm_mmu_page *page)
694 {
695 u64 *parent_pte;
696
697 while (page->multimapped || page->parent_pte) {
698 if (!page->multimapped)
699 parent_pte = page->parent_pte;
700 else {
701 struct kvm_pte_chain *chain;
702
703 chain = container_of(page->parent_ptes.first,
704 struct kvm_pte_chain, link);
705 parent_pte = chain->parent_ptes[0];
706 }
707 BUG_ON(!parent_pte);
708 kvm_mmu_put_page(page, parent_pte);
709 set_shadow_pte(parent_pte, 0);
710 }
711 kvm_mmu_page_unlink_children(kvm, page);
712 if (!page->root_count) {
713 hlist_del(&page->hash_link);
714 kvm_mmu_free_page(kvm, page);
715 } else
716 list_move(&page->link, &kvm->active_mmu_pages);
717 }
718
719 static int kvm_mmu_unprotect_page(struct kvm_vcpu *vcpu, gfn_t gfn)
720 {
721 unsigned index;
722 struct hlist_head *bucket;
723 struct kvm_mmu_page *page;
724 struct hlist_node *node, *n;
725 int r;
726
727 pgprintk("%s: looking for gfn %lx\n", __FUNCTION__, gfn);
728 r = 0;
729 index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
730 bucket = &vcpu->kvm->mmu_page_hash[index];
731 hlist_for_each_entry_safe(page, node, n, bucket, hash_link)
732 if (page->gfn == gfn && !page->role.metaphysical) {
733 pgprintk("%s: gfn %lx role %x\n", __FUNCTION__, gfn,
734 page->role.word);
735 kvm_mmu_zap_page(vcpu->kvm, page);
736 r = 1;
737 }
738 return r;
739 }
740
741 static void mmu_unshadow(struct kvm_vcpu *vcpu, gfn_t gfn)
742 {
743 struct kvm_mmu_page *page;
744
745 while ((page = kvm_mmu_lookup_page(vcpu, gfn)) != NULL) {
746 pgprintk("%s: zap %lx %x\n",
747 __FUNCTION__, gfn, page->role.word);
748 kvm_mmu_zap_page(vcpu->kvm, page);
749 }
750 }
751
752 static void page_header_update_slot(struct kvm *kvm, void *pte, gpa_t gpa)
753 {
754 int slot = memslot_id(kvm, gfn_to_memslot(kvm, gpa >> PAGE_SHIFT));
755 struct kvm_mmu_page *page_head = page_header(__pa(pte));
756
757 __set_bit(slot, &page_head->slot_bitmap);
758 }
759
760 hpa_t safe_gpa_to_hpa(struct kvm_vcpu *vcpu, gpa_t gpa)
761 {
762 hpa_t hpa = gpa_to_hpa(vcpu, gpa);
763
764 return is_error_hpa(hpa) ? bad_page_address | (gpa & ~PAGE_MASK): hpa;
765 }
766
767 hpa_t gpa_to_hpa(struct kvm_vcpu *vcpu, gpa_t gpa)
768 {
769 struct page *page;
770
771 ASSERT((gpa & HPA_ERR_MASK) == 0);
772 page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);
773 if (!page)
774 return gpa | HPA_ERR_MASK;
775 return ((hpa_t)page_to_pfn(page) << PAGE_SHIFT)
776 | (gpa & (PAGE_SIZE-1));
777 }
778
779 hpa_t gva_to_hpa(struct kvm_vcpu *vcpu, gva_t gva)
780 {
781 gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, gva);
782
783 if (gpa == UNMAPPED_GVA)
784 return UNMAPPED_GVA;
785 return gpa_to_hpa(vcpu, gpa);
786 }
787
788 struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva)
789 {
790 gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, gva);
791
792 if (gpa == UNMAPPED_GVA)
793 return NULL;
794 return pfn_to_page(gpa_to_hpa(vcpu, gpa) >> PAGE_SHIFT);
795 }
796
797 static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
798 {
799 }
800
801 static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, hpa_t p)
802 {
803 int level = PT32E_ROOT_LEVEL;
804 hpa_t table_addr = vcpu->mmu.root_hpa;
805
806 for (; ; level--) {
807 u32 index = PT64_INDEX(v, level);
808 u64 *table;
809 u64 pte;
810
811 ASSERT(VALID_PAGE(table_addr));
812 table = __va(table_addr);
813
814 if (level == 1) {
815 pte = table[index];
816 if (is_present_pte(pte) && is_writeble_pte(pte))
817 return 0;
818 mark_page_dirty(vcpu->kvm, v >> PAGE_SHIFT);
819 page_header_update_slot(vcpu->kvm, table, v);
820 table[index] = p | PT_PRESENT_MASK | PT_WRITABLE_MASK |
821 PT_USER_MASK;
822 rmap_add(vcpu, &table[index]);
823 return 0;
824 }
825
826 if (table[index] == 0) {
827 struct kvm_mmu_page *new_table;
828 gfn_t pseudo_gfn;
829
830 pseudo_gfn = (v & PT64_DIR_BASE_ADDR_MASK)
831 >> PAGE_SHIFT;
832 new_table = kvm_mmu_get_page(vcpu, pseudo_gfn,
833 v, level - 1,
834 1, 0, &table[index]);
835 if (!new_table) {
836 pgprintk("nonpaging_map: ENOMEM\n");
837 return -ENOMEM;
838 }
839
840 table[index] = __pa(new_table->spt) | PT_PRESENT_MASK
841 | PT_WRITABLE_MASK | PT_USER_MASK;
842 }
843 table_addr = table[index] & PT64_BASE_ADDR_MASK;
844 }
845 }
846
847 static void mmu_free_roots(struct kvm_vcpu *vcpu)
848 {
849 int i;
850 struct kvm_mmu_page *page;
851
852 if (!VALID_PAGE(vcpu->mmu.root_hpa))
853 return;
854 #ifdef CONFIG_X86_64
855 if (vcpu->mmu.shadow_root_level == PT64_ROOT_LEVEL) {
856 hpa_t root = vcpu->mmu.root_hpa;
857
858 page = page_header(root);
859 --page->root_count;
860 vcpu->mmu.root_hpa = INVALID_PAGE;
861 return;
862 }
863 #endif
864 for (i = 0; i < 4; ++i) {
865 hpa_t root = vcpu->mmu.pae_root[i];
866
867 if (root) {
868 root &= PT64_BASE_ADDR_MASK;
869 page = page_header(root);
870 --page->root_count;
871 }
872 vcpu->mmu.pae_root[i] = INVALID_PAGE;
873 }
874 vcpu->mmu.root_hpa = INVALID_PAGE;
875 }
876
877 static void mmu_alloc_roots(struct kvm_vcpu *vcpu)
878 {
879 int i;
880 gfn_t root_gfn;
881 struct kvm_mmu_page *page;
882
883 root_gfn = vcpu->cr3 >> PAGE_SHIFT;
884
885 #ifdef CONFIG_X86_64
886 if (vcpu->mmu.shadow_root_level == PT64_ROOT_LEVEL) {
887 hpa_t root = vcpu->mmu.root_hpa;
888
889 ASSERT(!VALID_PAGE(root));
890 page = kvm_mmu_get_page(vcpu, root_gfn, 0,
891 PT64_ROOT_LEVEL, 0, 0, NULL);
892 root = __pa(page->spt);
893 ++page->root_count;
894 vcpu->mmu.root_hpa = root;
895 return;
896 }
897 #endif
898 for (i = 0; i < 4; ++i) {
899 hpa_t root = vcpu->mmu.pae_root[i];
900
901 ASSERT(!VALID_PAGE(root));
902 if (vcpu->mmu.root_level == PT32E_ROOT_LEVEL) {
903 if (!is_present_pte(vcpu->pdptrs[i])) {
904 vcpu->mmu.pae_root[i] = 0;
905 continue;
906 }
907 root_gfn = vcpu->pdptrs[i] >> PAGE_SHIFT;
908 } else if (vcpu->mmu.root_level == 0)
909 root_gfn = 0;
910 page = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
911 PT32_ROOT_LEVEL, !is_paging(vcpu),
912 0, NULL);
913 root = __pa(page->spt);
914 ++page->root_count;
915 vcpu->mmu.pae_root[i] = root | PT_PRESENT_MASK;
916 }
917 vcpu->mmu.root_hpa = __pa(vcpu->mmu.pae_root);
918 }
919
920 static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr)
921 {
922 return vaddr;
923 }
924
925 static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
926 u32 error_code)
927 {
928 gpa_t addr = gva;
929 hpa_t paddr;
930 int r;
931
932 r = mmu_topup_memory_caches(vcpu);
933 if (r)
934 return r;
935
936 ASSERT(vcpu);
937 ASSERT(VALID_PAGE(vcpu->mmu.root_hpa));
938
939
940 paddr = gpa_to_hpa(vcpu , addr & PT64_BASE_ADDR_MASK);
941
942 if (is_error_hpa(paddr))
943 return 1;
944
945 return nonpaging_map(vcpu, addr & PAGE_MASK, paddr);
946 }
947
948 static void nonpaging_free(struct kvm_vcpu *vcpu)
949 {
950 mmu_free_roots(vcpu);
951 }
952
953 static int nonpaging_init_context(struct kvm_vcpu *vcpu)
954 {
955 struct kvm_mmu *context = &vcpu->mmu;
956
957 context->new_cr3 = nonpaging_new_cr3;
958 context->page_fault = nonpaging_page_fault;
959 context->gva_to_gpa = nonpaging_gva_to_gpa;
960 context->free = nonpaging_free;
961 context->root_level = 0;
962 context->shadow_root_level = PT32E_ROOT_LEVEL;
963 context->root_hpa = INVALID_PAGE;
964 return 0;
965 }
966
967 static void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
968 {
969 ++vcpu->stat.tlb_flush;
970 kvm_arch_ops->tlb_flush(vcpu);
971 }
972
973 static void paging_new_cr3(struct kvm_vcpu *vcpu)
974 {
975 pgprintk("%s: cr3 %lx\n", __FUNCTION__, vcpu->cr3);
976 mmu_free_roots(vcpu);
977 }
978
979 static void inject_page_fault(struct kvm_vcpu *vcpu,
980 u64 addr,
981 u32 err_code)
982 {
983 kvm_arch_ops->inject_page_fault(vcpu, addr, err_code);
984 }
985
986 static void paging_free(struct kvm_vcpu *vcpu)
987 {
988 nonpaging_free(vcpu);
989 }
990
991 #define PTTYPE 64
992 #include "paging_tmpl.h"
993 #undef PTTYPE
994
995 #define PTTYPE 32
996 #include "paging_tmpl.h"
997 #undef PTTYPE
998
999 static int paging64_init_context_common(struct kvm_vcpu *vcpu, int level)
1000 {
1001 struct kvm_mmu *context = &vcpu->mmu;
1002
1003 ASSERT(is_pae(vcpu));
1004 context->new_cr3 = paging_new_cr3;
1005 context->page_fault = paging64_page_fault;
1006 context->gva_to_gpa = paging64_gva_to_gpa;
1007 context->free = paging_free;
1008 context->root_level = level;
1009 context->shadow_root_level = level;
1010 context->root_hpa = INVALID_PAGE;
1011 return 0;
1012 }
1013
1014 static int paging64_init_context(struct kvm_vcpu *vcpu)
1015 {
1016 return paging64_init_context_common(vcpu, PT64_ROOT_LEVEL);
1017 }
1018
1019 static int paging32_init_context(struct kvm_vcpu *vcpu)
1020 {
1021 struct kvm_mmu *context = &vcpu->mmu;
1022
1023 context->new_cr3 = paging_new_cr3;
1024 context->page_fault = paging32_page_fault;
1025 context->gva_to_gpa = paging32_gva_to_gpa;
1026 context->free = paging_free;
1027 context->root_level = PT32_ROOT_LEVEL;
1028 context->shadow_root_level = PT32E_ROOT_LEVEL;
1029 context->root_hpa = INVALID_PAGE;
1030 return 0;
1031 }
1032
1033 static int paging32E_init_context(struct kvm_vcpu *vcpu)
1034 {
1035 return paging64_init_context_common(vcpu, PT32E_ROOT_LEVEL);
1036 }
1037
1038 static int init_kvm_mmu(struct kvm_vcpu *vcpu)
1039 {
1040 ASSERT(vcpu);
1041 ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));
1042
1043 if (!is_paging(vcpu))
1044 return nonpaging_init_context(vcpu);
1045 else if (is_long_mode(vcpu))
1046 return paging64_init_context(vcpu);
1047 else if (is_pae(vcpu))
1048 return paging32E_init_context(vcpu);
1049 else
1050 return paging32_init_context(vcpu);
1051 }
1052
1053 static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
1054 {
1055 ASSERT(vcpu);
1056 if (VALID_PAGE(vcpu->mmu.root_hpa)) {
1057 vcpu->mmu.free(vcpu);
1058 vcpu->mmu.root_hpa = INVALID_PAGE;
1059 }
1060 }
1061
1062 int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
1063 {
1064 destroy_kvm_mmu(vcpu);
1065 return init_kvm_mmu(vcpu);
1066 }
1067
1068 int kvm_mmu_load(struct kvm_vcpu *vcpu)
1069 {
1070 int r;
1071
1072 spin_lock(&vcpu->kvm->lock);
1073 r = mmu_topup_memory_caches(vcpu);
1074 if (r)
1075 goto out;
1076 mmu_alloc_roots(vcpu);
1077 kvm_arch_ops->set_cr3(vcpu, vcpu->mmu.root_hpa);
1078 kvm_mmu_flush_tlb(vcpu);
1079 out:
1080 spin_unlock(&vcpu->kvm->lock);
1081 return r;
1082 }
1083 EXPORT_SYMBOL_GPL(kvm_mmu_load);
1084
1085 void kvm_mmu_unload(struct kvm_vcpu *vcpu)
1086 {
1087 mmu_free_roots(vcpu);
1088 }
1089
1090 static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
1091 struct kvm_mmu_page *page,
1092 u64 *spte)
1093 {
1094 u64 pte;
1095 struct kvm_mmu_page *child;
1096
1097 pte = *spte;
1098 if (is_present_pte(pte)) {
1099 if (page->role.level == PT_PAGE_TABLE_LEVEL)
1100 rmap_remove(spte);
1101 else {
1102 child = page_header(pte & PT64_BASE_ADDR_MASK);
1103 mmu_page_remove_parent_pte(child, spte);
1104 }
1105 }
1106 *spte = 0;
1107 kvm_flush_remote_tlbs(vcpu->kvm);
1108 }
1109
1110 static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
1111 struct kvm_mmu_page *page,
1112 u64 *spte,
1113 const void *new, int bytes)
1114 {
1115 if (page->role.level != PT_PAGE_TABLE_LEVEL)
1116 return;
1117
1118 if (page->role.glevels == PT32_ROOT_LEVEL)
1119 paging32_update_pte(vcpu, page, spte, new, bytes);
1120 else
1121 paging64_update_pte(vcpu, page, spte, new, bytes);
1122 }
1123
1124 void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
1125 const u8 *old, const u8 *new, int bytes)
1126 {
1127 gfn_t gfn = gpa >> PAGE_SHIFT;
1128 struct kvm_mmu_page *page;
1129 struct hlist_node *node, *n;
1130 struct hlist_head *bucket;
1131 unsigned index;
1132 u64 *spte;
1133 unsigned offset = offset_in_page(gpa);
1134 unsigned pte_size;
1135 unsigned page_offset;
1136 unsigned misaligned;
1137 unsigned quadrant;
1138 int level;
1139 int flooded = 0;
1140 int npte;
1141
1142 pgprintk("%s: gpa %llx bytes %d\n", __FUNCTION__, gpa, bytes);
1143 if (gfn == vcpu->last_pt_write_gfn) {
1144 ++vcpu->last_pt_write_count;
1145 if (vcpu->last_pt_write_count >= 3)
1146 flooded = 1;
1147 } else {
1148 vcpu->last_pt_write_gfn = gfn;
1149 vcpu->last_pt_write_count = 1;
1150 }
1151 index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
1152 bucket = &vcpu->kvm->mmu_page_hash[index];
1153 hlist_for_each_entry_safe(page, node, n, bucket, hash_link) {
1154 if (page->gfn != gfn || page->role.metaphysical)
1155 continue;
1156 pte_size = page->role.glevels == PT32_ROOT_LEVEL ? 4 : 8;
1157 misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
1158 misaligned |= bytes < 4;
1159 if (misaligned || flooded) {
1160 /*
1161 * Misaligned accesses are too much trouble to fix
1162 * up; also, they usually indicate a page is not used
1163 * as a page table.
1164 *
1165 * If we're seeing too many writes to a page,
1166 * it may no longer be a page table, or we may be
1167 * forking, in which case it is better to unmap the
1168 * page.
1169 */
1170 pgprintk("misaligned: gpa %llx bytes %d role %x\n",
1171 gpa, bytes, page->role.word);
1172 kvm_mmu_zap_page(vcpu->kvm, page);
1173 continue;
1174 }
1175 page_offset = offset;
1176 level = page->role.level;
1177 npte = 1;
1178 if (page->role.glevels == PT32_ROOT_LEVEL) {
1179 page_offset <<= 1; /* 32->64 */
1180 /*
1181 * A 32-bit pde maps 4MB while the shadow pdes map
1182 * only 2MB. So we need to double the offset again
1183 * and zap two pdes instead of one.
1184 */
1185 if (level == PT32_ROOT_LEVEL) {
1186 page_offset &= ~7; /* kill rounding error */
1187 page_offset <<= 1;
1188 npte = 2;
1189 }
1190 quadrant = page_offset >> PAGE_SHIFT;
1191 page_offset &= ~PAGE_MASK;
1192 if (quadrant != page->role.quadrant)
1193 continue;
1194 }
1195 spte = &page->spt[page_offset / sizeof(*spte)];
1196 while (npte--) {
1197 mmu_pte_write_zap_pte(vcpu, page, spte);
1198 mmu_pte_write_new_pte(vcpu, page, spte, new, bytes);
1199 ++spte;
1200 }
1201 }
1202 }
1203
1204 int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
1205 {
1206 gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, gva);
1207
1208 return kvm_mmu_unprotect_page(vcpu, gpa >> PAGE_SHIFT);
1209 }
1210
1211 void kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
1212 {
1213 while (vcpu->kvm->n_free_mmu_pages < KVM_REFILL_PAGES) {
1214 struct kvm_mmu_page *page;
1215
1216 page = container_of(vcpu->kvm->active_mmu_pages.prev,
1217 struct kvm_mmu_page, link);
1218 kvm_mmu_zap_page(vcpu->kvm, page);
1219 }
1220 }
1221 EXPORT_SYMBOL_GPL(kvm_mmu_free_some_pages);
1222
1223 static void free_mmu_pages(struct kvm_vcpu *vcpu)
1224 {
1225 struct kvm_mmu_page *page;
1226
1227 while (!list_empty(&vcpu->kvm->active_mmu_pages)) {
1228 page = container_of(vcpu->kvm->active_mmu_pages.next,
1229 struct kvm_mmu_page, link);
1230 kvm_mmu_zap_page(vcpu->kvm, page);
1231 }
1232 free_page((unsigned long)vcpu->mmu.pae_root);
1233 }
1234
1235 static int alloc_mmu_pages(struct kvm_vcpu *vcpu)
1236 {
1237 struct page *page;
1238 int i;
1239
1240 ASSERT(vcpu);
1241
1242 vcpu->kvm->n_free_mmu_pages = KVM_NUM_MMU_PAGES;
1243
1244 /*
1245 * When emulating 32-bit mode, cr3 is only 32 bits even on x86_64.
1246 * Therefore we need to allocate shadow page tables in the first
1247 * 4GB of memory, which happens to fit the DMA32 zone.
1248 */
1249 page = alloc_page(GFP_KERNEL | __GFP_DMA32);
1250 if (!page)
1251 goto error_1;
1252 vcpu->mmu.pae_root = page_address(page);
1253 for (i = 0; i < 4; ++i)
1254 vcpu->mmu.pae_root[i] = INVALID_PAGE;
1255
1256 return 0;
1257
1258 error_1:
1259 free_mmu_pages(vcpu);
1260 return -ENOMEM;
1261 }
1262
1263 int kvm_mmu_create(struct kvm_vcpu *vcpu)
1264 {
1265 ASSERT(vcpu);
1266 ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));
1267
1268 return alloc_mmu_pages(vcpu);
1269 }
1270
1271 int kvm_mmu_setup(struct kvm_vcpu *vcpu)
1272 {
1273 ASSERT(vcpu);
1274 ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));
1275
1276 return init_kvm_mmu(vcpu);
1277 }
1278
1279 void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
1280 {
1281 ASSERT(vcpu);
1282
1283 destroy_kvm_mmu(vcpu);
1284 free_mmu_pages(vcpu);
1285 mmu_free_memory_caches(vcpu);
1286 }
1287
1288 void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
1289 {
1290 struct kvm_mmu_page *page;
1291
1292 list_for_each_entry(page, &kvm->active_mmu_pages, link) {
1293 int i;
1294 u64 *pt;
1295
1296 if (!test_bit(slot, &page->slot_bitmap))
1297 continue;
1298
1299 pt = page->spt;
1300 for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
1301 /* avoid RMW */
1302 if (pt[i] & PT_WRITABLE_MASK) {
1303 rmap_remove(&pt[i]);
1304 pt[i] &= ~PT_WRITABLE_MASK;
1305 }
1306 }
1307 }
1308
1309 void kvm_mmu_zap_all(struct kvm *kvm)
1310 {
1311 struct kvm_mmu_page *page, *node;
1312
1313 list_for_each_entry_safe(page, node, &kvm->active_mmu_pages, link)
1314 kvm_mmu_zap_page(kvm, page);
1315
1316 kvm_flush_remote_tlbs(kvm);
1317 }
1318
1319 void kvm_mmu_module_exit(void)
1320 {
1321 if (pte_chain_cache)
1322 kmem_cache_destroy(pte_chain_cache);
1323 if (rmap_desc_cache)
1324 kmem_cache_destroy(rmap_desc_cache);
1325 if (mmu_page_header_cache)
1326 kmem_cache_destroy(mmu_page_header_cache);
1327 }
1328
1329 int kvm_mmu_module_init(void)
1330 {
1331 pte_chain_cache = kmem_cache_create("kvm_pte_chain",
1332 sizeof(struct kvm_pte_chain),
1333 0, 0, NULL);
1334 if (!pte_chain_cache)
1335 goto nomem;
1336 rmap_desc_cache = kmem_cache_create("kvm_rmap_desc",
1337 sizeof(struct kvm_rmap_desc),
1338 0, 0, NULL);
1339 if (!rmap_desc_cache)
1340 goto nomem;
1341
1342 mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
1343 sizeof(struct kvm_mmu_page),
1344 0, 0, NULL);
1345 if (!mmu_page_header_cache)
1346 goto nomem;
1347
1348 return 0;
1349
1350 nomem:
1351 kvm_mmu_module_exit();
1352 return -ENOMEM;
1353 }
1354
1355 #ifdef AUDIT
1356
1357 static const char *audit_msg;
1358
1359 static gva_t canonicalize(gva_t gva)
1360 {
1361 #ifdef CONFIG_X86_64
1362 gva = (long long)(gva << 16) >> 16;
1363 #endif
1364 return gva;
1365 }
1366
1367 static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
1368 gva_t va, int level)
1369 {
1370 u64 *pt = __va(page_pte & PT64_BASE_ADDR_MASK);
1371 int i;
1372 gva_t va_delta = 1ul << (PAGE_SHIFT + 9 * (level - 1));
1373
1374 for (i = 0; i < PT64_ENT_PER_PAGE; ++i, va += va_delta) {
1375 u64 ent = pt[i];
1376
1377 if (!(ent & PT_PRESENT_MASK))
1378 continue;
1379
1380 va = canonicalize(va);
1381 if (level > 1)
1382 audit_mappings_page(vcpu, ent, va, level - 1);
1383 else {
1384 gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, va);
1385 hpa_t hpa = gpa_to_hpa(vcpu, gpa);
1386
1387 if ((ent & PT_PRESENT_MASK)
1388 && (ent & PT64_BASE_ADDR_MASK) != hpa)
1389 printk(KERN_ERR "audit error: (%s) levels %d"
1390 " gva %lx gpa %llx hpa %llx ent %llx\n",
1391 audit_msg, vcpu->mmu.root_level,
1392 va, gpa, hpa, ent);
1393 }
1394 }
1395 }
1396
1397 static void audit_mappings(struct kvm_vcpu *vcpu)
1398 {
1399 unsigned i;
1400
1401 if (vcpu->mmu.root_level == 4)
1402 audit_mappings_page(vcpu, vcpu->mmu.root_hpa, 0, 4);
1403 else
1404 for (i = 0; i < 4; ++i)
1405 if (vcpu->mmu.pae_root[i] & PT_PRESENT_MASK)
1406 audit_mappings_page(vcpu,
1407 vcpu->mmu.pae_root[i],
1408 i << 30,
1409 2);
1410 }
1411
1412 static int count_rmaps(struct kvm_vcpu *vcpu)
1413 {
1414 int nmaps = 0;
1415 int i, j, k;
1416
1417 for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
1418 struct kvm_memory_slot *m = &vcpu->kvm->memslots[i];
1419 struct kvm_rmap_desc *d;
1420
1421 for (j = 0; j < m->npages; ++j) {
1422 struct page *page = m->phys_mem[j];
1423
1424 if (!page->private)
1425 continue;
1426 if (!(page->private & 1)) {
1427 ++nmaps;
1428 continue;
1429 }
1430 d = (struct kvm_rmap_desc *)(page->private & ~1ul);
1431 while (d) {
1432 for (k = 0; k < RMAP_EXT; ++k)
1433 if (d->shadow_ptes[k])
1434 ++nmaps;
1435 else
1436 break;
1437 d = d->more;
1438 }
1439 }
1440 }
1441 return nmaps;
1442 }
1443
1444 static int count_writable_mappings(struct kvm_vcpu *vcpu)
1445 {
1446 int nmaps = 0;
1447 struct kvm_mmu_page *page;
1448 int i;
1449
1450 list_for_each_entry(page, &vcpu->kvm->active_mmu_pages, link) {
1451 u64 *pt = page->spt;
1452
1453 if (page->role.level != PT_PAGE_TABLE_LEVEL)
1454 continue;
1455
1456 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
1457 u64 ent = pt[i];
1458
1459 if (!(ent & PT_PRESENT_MASK))
1460 continue;
1461 if (!(ent & PT_WRITABLE_MASK))
1462 continue;
1463 ++nmaps;
1464 }
1465 }
1466 return nmaps;
1467 }
1468
1469 static void audit_rmap(struct kvm_vcpu *vcpu)
1470 {
1471 int n_rmap = count_rmaps(vcpu);
1472 int n_actual = count_writable_mappings(vcpu);
1473
1474 if (n_rmap != n_actual)
1475 printk(KERN_ERR "%s: (%s) rmap %d actual %d\n",
1476 __FUNCTION__, audit_msg, n_rmap, n_actual);
1477 }
1478
1479 static void audit_write_protection(struct kvm_vcpu *vcpu)
1480 {
1481 struct kvm_mmu_page *page;
1482
1483 list_for_each_entry(page, &vcpu->kvm->active_mmu_pages, link) {
1484 hfn_t hfn;
1485 struct page *pg;
1486
1487 if (page->role.metaphysical)
1488 continue;
1489
1490 hfn = gpa_to_hpa(vcpu, (gpa_t)page->gfn << PAGE_SHIFT)
1491 >> PAGE_SHIFT;
1492 pg = pfn_to_page(hfn);
1493 if (pg->private)
1494 printk(KERN_ERR "%s: (%s) shadow page has writable"
1495 " mappings: gfn %lx role %x\n",
1496 __FUNCTION__, audit_msg, page->gfn,
1497 page->role.word);
1498 }
1499 }
1500
1501 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg)
1502 {
1503 int olddbg = dbg;
1504
1505 dbg = 0;
1506 audit_msg = msg;
1507 audit_rmap(vcpu);
1508 audit_write_protection(vcpu);
1509 audit_mappings(vcpu);
1510 dbg = olddbg;
1511 }
1512
1513 #endif
Linux kernel - Deliverables
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