[PATCH] KVM: MMU: Free pages on kvm destruction
[linux-2.6] / 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 #include <linux/types.h>
20 #include <linux/string.h>
21 #include <asm/page.h>
22 #include <linux/mm.h>
23 #include <linux/highmem.h>
24 #include <linux/module.h>
25
26 #include "vmx.h"
27 #include "kvm.h"
28
29 #define pgprintk(x...) do { printk(x); } while (0)
30 #define rmap_printk(x...) do { printk(x); } while (0)
31
32 #define ASSERT(x)                                                       \
33         if (!(x)) {                                                     \
34                 printk(KERN_WARNING "assertion failed %s:%d: %s\n",     \
35                        __FILE__, __LINE__, #x);                         \
36         }
37
38 #define PT64_PT_BITS 9
39 #define PT64_ENT_PER_PAGE (1 << PT64_PT_BITS)
40 #define PT32_PT_BITS 10
41 #define PT32_ENT_PER_PAGE (1 << PT32_PT_BITS)
42
43 #define PT_WRITABLE_SHIFT 1
44
45 #define PT_PRESENT_MASK (1ULL << 0)
46 #define PT_WRITABLE_MASK (1ULL << PT_WRITABLE_SHIFT)
47 #define PT_USER_MASK (1ULL << 2)
48 #define PT_PWT_MASK (1ULL << 3)
49 #define PT_PCD_MASK (1ULL << 4)
50 #define PT_ACCESSED_MASK (1ULL << 5)
51 #define PT_DIRTY_MASK (1ULL << 6)
52 #define PT_PAGE_SIZE_MASK (1ULL << 7)
53 #define PT_PAT_MASK (1ULL << 7)
54 #define PT_GLOBAL_MASK (1ULL << 8)
55 #define PT64_NX_MASK (1ULL << 63)
56
57 #define PT_PAT_SHIFT 7
58 #define PT_DIR_PAT_SHIFT 12
59 #define PT_DIR_PAT_MASK (1ULL << PT_DIR_PAT_SHIFT)
60
61 #define PT32_DIR_PSE36_SIZE 4
62 #define PT32_DIR_PSE36_SHIFT 13
63 #define PT32_DIR_PSE36_MASK (((1ULL << PT32_DIR_PSE36_SIZE) - 1) << PT32_DIR_PSE36_SHIFT)
64
65
66 #define PT32_PTE_COPY_MASK \
67         (PT_PRESENT_MASK | PT_ACCESSED_MASK | PT_DIRTY_MASK | PT_GLOBAL_MASK)
68
69 #define PT64_PTE_COPY_MASK (PT64_NX_MASK | PT32_PTE_COPY_MASK)
70
71 #define PT_FIRST_AVAIL_BITS_SHIFT 9
72 #define PT64_SECOND_AVAIL_BITS_SHIFT 52
73
74 #define PT_SHADOW_PS_MARK (1ULL << PT_FIRST_AVAIL_BITS_SHIFT)
75 #define PT_SHADOW_IO_MARK (1ULL << PT_FIRST_AVAIL_BITS_SHIFT)
76
77 #define PT_SHADOW_WRITABLE_SHIFT (PT_FIRST_AVAIL_BITS_SHIFT + 1)
78 #define PT_SHADOW_WRITABLE_MASK (1ULL << PT_SHADOW_WRITABLE_SHIFT)
79
80 #define PT_SHADOW_USER_SHIFT (PT_SHADOW_WRITABLE_SHIFT + 1)
81 #define PT_SHADOW_USER_MASK (1ULL << (PT_SHADOW_USER_SHIFT))
82
83 #define PT_SHADOW_BITS_OFFSET (PT_SHADOW_WRITABLE_SHIFT - PT_WRITABLE_SHIFT)
84
85 #define VALID_PAGE(x) ((x) != INVALID_PAGE)
86
87 #define PT64_LEVEL_BITS 9
88
89 #define PT64_LEVEL_SHIFT(level) \
90                 ( PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS )
91
92 #define PT64_LEVEL_MASK(level) \
93                 (((1ULL << PT64_LEVEL_BITS) - 1) << PT64_LEVEL_SHIFT(level))
94
95 #define PT64_INDEX(address, level)\
96         (((address) >> PT64_LEVEL_SHIFT(level)) & ((1 << PT64_LEVEL_BITS) - 1))
97
98
99 #define PT32_LEVEL_BITS 10
100
101 #define PT32_LEVEL_SHIFT(level) \
102                 ( PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS )
103
104 #define PT32_LEVEL_MASK(level) \
105                 (((1ULL << PT32_LEVEL_BITS) - 1) << PT32_LEVEL_SHIFT(level))
106
107 #define PT32_INDEX(address, level)\
108         (((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))
109
110
111 #define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & PAGE_MASK)
112 #define PT64_DIR_BASE_ADDR_MASK \
113         (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))
114
115 #define PT32_BASE_ADDR_MASK PAGE_MASK
116 #define PT32_DIR_BASE_ADDR_MASK \
117         (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
118
119
120 #define PFERR_PRESENT_MASK (1U << 0)
121 #define PFERR_WRITE_MASK (1U << 1)
122 #define PFERR_USER_MASK (1U << 2)
123
124 #define PT64_ROOT_LEVEL 4
125 #define PT32_ROOT_LEVEL 2
126 #define PT32E_ROOT_LEVEL 3
127
128 #define PT_DIRECTORY_LEVEL 2
129 #define PT_PAGE_TABLE_LEVEL 1
130
131 #define RMAP_EXT 4
132
133 struct kvm_rmap_desc {
134         u64 *shadow_ptes[RMAP_EXT];
135         struct kvm_rmap_desc *more;
136 };
137
138 static int is_write_protection(struct kvm_vcpu *vcpu)
139 {
140         return vcpu->cr0 & CR0_WP_MASK;
141 }
142
143 static int is_cpuid_PSE36(void)
144 {
145         return 1;
146 }
147
148 static int is_present_pte(unsigned long pte)
149 {
150         return pte & PT_PRESENT_MASK;
151 }
152
153 static int is_writeble_pte(unsigned long pte)
154 {
155         return pte & PT_WRITABLE_MASK;
156 }
157
158 static int is_io_pte(unsigned long pte)
159 {
160         return pte & PT_SHADOW_IO_MARK;
161 }
162
163 static int is_rmap_pte(u64 pte)
164 {
165         return (pte & (PT_WRITABLE_MASK | PT_PRESENT_MASK))
166                 == (PT_WRITABLE_MASK | PT_PRESENT_MASK);
167 }
168
169 /*
170  * Reverse mapping data structures:
171  *
172  * If page->private bit zero is zero, then page->private points to the
173  * shadow page table entry that points to page_address(page).
174  *
175  * If page->private bit zero is one, (then page->private & ~1) points
176  * to a struct kvm_rmap_desc containing more mappings.
177  */
178 static void rmap_add(struct kvm *kvm, u64 *spte)
179 {
180         struct page *page;
181         struct kvm_rmap_desc *desc;
182         int i;
183
184         if (!is_rmap_pte(*spte))
185                 return;
186         page = pfn_to_page((*spte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT);
187         if (!page->private) {
188                 rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte);
189                 page->private = (unsigned long)spte;
190         } else if (!(page->private & 1)) {
191                 rmap_printk("rmap_add: %p %llx 1->many\n", spte, *spte);
192                 desc = kzalloc(sizeof *desc, GFP_NOWAIT);
193                 if (!desc)
194                         BUG(); /* FIXME: return error */
195                 desc->shadow_ptes[0] = (u64 *)page->private;
196                 desc->shadow_ptes[1] = spte;
197                 page->private = (unsigned long)desc | 1;
198         } else {
199                 rmap_printk("rmap_add: %p %llx many->many\n", spte, *spte);
200                 desc = (struct kvm_rmap_desc *)(page->private & ~1ul);
201                 while (desc->shadow_ptes[RMAP_EXT-1] && desc->more)
202                         desc = desc->more;
203                 if (desc->shadow_ptes[RMAP_EXT-1]) {
204                         desc->more = kzalloc(sizeof *desc->more, GFP_NOWAIT);
205                         if (!desc->more)
206                                 BUG(); /* FIXME: return error */
207                         desc = desc->more;
208                 }
209                 for (i = 0; desc->shadow_ptes[i]; ++i)
210                         ;
211                 desc->shadow_ptes[i] = spte;
212         }
213 }
214
215 static void rmap_desc_remove_entry(struct page *page,
216                                    struct kvm_rmap_desc *desc,
217                                    int i,
218                                    struct kvm_rmap_desc *prev_desc)
219 {
220         int j;
221
222         for (j = RMAP_EXT - 1; !desc->shadow_ptes[j] && j > i; --j)
223                 ;
224         desc->shadow_ptes[i] = desc->shadow_ptes[j];
225         desc->shadow_ptes[j] = 0;
226         if (j != 0)
227                 return;
228         if (!prev_desc && !desc->more)
229                 page->private = (unsigned long)desc->shadow_ptes[0];
230         else
231                 if (prev_desc)
232                         prev_desc->more = desc->more;
233                 else
234                         page->private = (unsigned long)desc->more | 1;
235         kfree(desc);
236 }
237
238 static void rmap_remove(struct kvm *kvm, u64 *spte)
239 {
240         struct page *page;
241         struct kvm_rmap_desc *desc;
242         struct kvm_rmap_desc *prev_desc;
243         int i;
244
245         if (!is_rmap_pte(*spte))
246                 return;
247         page = pfn_to_page((*spte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT);
248         if (!page->private) {
249                 printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte);
250                 BUG();
251         } else if (!(page->private & 1)) {
252                 rmap_printk("rmap_remove:  %p %llx 1->0\n", spte, *spte);
253                 if ((u64 *)page->private != spte) {
254                         printk(KERN_ERR "rmap_remove:  %p %llx 1->BUG\n",
255                                spte, *spte);
256                         BUG();
257                 }
258                 page->private = 0;
259         } else {
260                 rmap_printk("rmap_remove:  %p %llx many->many\n", spte, *spte);
261                 desc = (struct kvm_rmap_desc *)(page->private & ~1ul);
262                 prev_desc = NULL;
263                 while (desc) {
264                         for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i)
265                                 if (desc->shadow_ptes[i] == spte) {
266                                         rmap_desc_remove_entry(page, desc, i,
267                                                                prev_desc);
268                                         return;
269                                 }
270                         prev_desc = desc;
271                         desc = desc->more;
272                 }
273                 BUG();
274         }
275 }
276
277 static void rmap_write_protect(struct kvm *kvm, u64 gfn)
278 {
279         struct page *page;
280         struct kvm_memory_slot *slot;
281         struct kvm_rmap_desc *desc;
282         u64 *spte;
283
284         slot = gfn_to_memslot(kvm, gfn);
285         BUG_ON(!slot);
286         page = gfn_to_page(slot, gfn);
287
288         while (page->private) {
289                 if (!(page->private & 1))
290                         spte = (u64 *)page->private;
291                 else {
292                         desc = (struct kvm_rmap_desc *)(page->private & ~1ul);
293                         spte = desc->shadow_ptes[0];
294                 }
295                 BUG_ON(!spte);
296                 BUG_ON((*spte & PT64_BASE_ADDR_MASK) !=
297                        page_to_pfn(page) << PAGE_SHIFT);
298                 BUG_ON(!(*spte & PT_PRESENT_MASK));
299                 BUG_ON(!(*spte & PT_WRITABLE_MASK));
300                 rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
301                 rmap_remove(kvm, spte);
302                 *spte &= ~(u64)PT_WRITABLE_MASK;
303         }
304 }
305
306 static int is_empty_shadow_page(hpa_t page_hpa)
307 {
308         u64 *pos;
309         u64 *end;
310
311         for (pos = __va(page_hpa), end = pos + PAGE_SIZE / sizeof(u64);
312                       pos != end; pos++)
313                 if (*pos != 0) {
314                         printk(KERN_ERR "%s: %p %llx\n", __FUNCTION__,
315                                pos, *pos);
316                         return 0;
317                 }
318         return 1;
319 }
320
321 static void kvm_mmu_free_page(struct kvm_vcpu *vcpu, hpa_t page_hpa)
322 {
323         struct kvm_mmu_page *page_head = page_header(page_hpa);
324
325         ASSERT(is_empty_shadow_page(page_hpa));
326         list_del(&page_head->link);
327         page_head->page_hpa = page_hpa;
328         list_add(&page_head->link, &vcpu->free_pages);
329         ++vcpu->kvm->n_free_mmu_pages;
330 }
331
332 static unsigned kvm_page_table_hashfn(gfn_t gfn)
333 {
334         return gfn;
335 }
336
337 static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
338                                                u64 *parent_pte)
339 {
340         struct kvm_mmu_page *page;
341
342         if (list_empty(&vcpu->free_pages))
343                 return NULL;
344
345         page = list_entry(vcpu->free_pages.next, struct kvm_mmu_page, link);
346         list_del(&page->link);
347         list_add(&page->link, &vcpu->kvm->active_mmu_pages);
348         ASSERT(is_empty_shadow_page(page->page_hpa));
349         page->slot_bitmap = 0;
350         page->global = 1;
351         page->multimapped = 0;
352         page->parent_pte = parent_pte;
353         --vcpu->kvm->n_free_mmu_pages;
354         return page;
355 }
356
357 static void mmu_page_add_parent_pte(struct kvm_mmu_page *page, u64 *parent_pte)
358 {
359         struct kvm_pte_chain *pte_chain;
360         struct hlist_node *node;
361         int i;
362
363         if (!parent_pte)
364                 return;
365         if (!page->multimapped) {
366                 u64 *old = page->parent_pte;
367
368                 if (!old) {
369                         page->parent_pte = parent_pte;
370                         return;
371                 }
372                 page->multimapped = 1;
373                 pte_chain = kzalloc(sizeof(struct kvm_pte_chain), GFP_NOWAIT);
374                 BUG_ON(!pte_chain);
375                 INIT_HLIST_HEAD(&page->parent_ptes);
376                 hlist_add_head(&pte_chain->link, &page->parent_ptes);
377                 pte_chain->parent_ptes[0] = old;
378         }
379         hlist_for_each_entry(pte_chain, node, &page->parent_ptes, link) {
380                 if (pte_chain->parent_ptes[NR_PTE_CHAIN_ENTRIES-1])
381                         continue;
382                 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i)
383                         if (!pte_chain->parent_ptes[i]) {
384                                 pte_chain->parent_ptes[i] = parent_pte;
385                                 return;
386                         }
387         }
388         pte_chain = kzalloc(sizeof(struct kvm_pte_chain), GFP_NOWAIT);
389         BUG_ON(!pte_chain);
390         hlist_add_head(&pte_chain->link, &page->parent_ptes);
391         pte_chain->parent_ptes[0] = parent_pte;
392 }
393
394 static void mmu_page_remove_parent_pte(struct kvm_mmu_page *page,
395                                        u64 *parent_pte)
396 {
397         struct kvm_pte_chain *pte_chain;
398         struct hlist_node *node;
399         int i;
400
401         if (!page->multimapped) {
402                 BUG_ON(page->parent_pte != parent_pte);
403                 page->parent_pte = NULL;
404                 return;
405         }
406         hlist_for_each_entry(pte_chain, node, &page->parent_ptes, link)
407                 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
408                         if (!pte_chain->parent_ptes[i])
409                                 break;
410                         if (pte_chain->parent_ptes[i] != parent_pte)
411                                 continue;
412                         while (i + 1 < NR_PTE_CHAIN_ENTRIES
413                                 && pte_chain->parent_ptes[i + 1]) {
414                                 pte_chain->parent_ptes[i]
415                                         = pte_chain->parent_ptes[i + 1];
416                                 ++i;
417                         }
418                         pte_chain->parent_ptes[i] = NULL;
419                         if (i == 0) {
420                                 hlist_del(&pte_chain->link);
421                                 kfree(pte_chain);
422                                 if (hlist_empty(&page->parent_ptes)) {
423                                         page->multimapped = 0;
424                                         page->parent_pte = NULL;
425                                 }
426                         }
427                         return;
428                 }
429         BUG();
430 }
431
432 static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm_vcpu *vcpu,
433                                                 gfn_t gfn)
434 {
435         unsigned index;
436         struct hlist_head *bucket;
437         struct kvm_mmu_page *page;
438         struct hlist_node *node;
439
440         pgprintk("%s: looking for gfn %lx\n", __FUNCTION__, gfn);
441         index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
442         bucket = &vcpu->kvm->mmu_page_hash[index];
443         hlist_for_each_entry(page, node, bucket, hash_link)
444                 if (page->gfn == gfn && !page->role.metaphysical) {
445                         pgprintk("%s: found role %x\n",
446                                  __FUNCTION__, page->role.word);
447                         return page;
448                 }
449         return NULL;
450 }
451
452 static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
453                                              gfn_t gfn,
454                                              gva_t gaddr,
455                                              unsigned level,
456                                              int metaphysical,
457                                              u64 *parent_pte)
458 {
459         union kvm_mmu_page_role role;
460         unsigned index;
461         unsigned quadrant;
462         struct hlist_head *bucket;
463         struct kvm_mmu_page *page;
464         struct hlist_node *node;
465
466         role.word = 0;
467         role.glevels = vcpu->mmu.root_level;
468         role.level = level;
469         role.metaphysical = metaphysical;
470         if (vcpu->mmu.root_level <= PT32_ROOT_LEVEL) {
471                 quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
472                 quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
473                 role.quadrant = quadrant;
474         }
475         pgprintk("%s: looking gfn %lx role %x\n", __FUNCTION__,
476                  gfn, role.word);
477         index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
478         bucket = &vcpu->kvm->mmu_page_hash[index];
479         hlist_for_each_entry(page, node, bucket, hash_link)
480                 if (page->gfn == gfn && page->role.word == role.word) {
481                         mmu_page_add_parent_pte(page, parent_pte);
482                         pgprintk("%s: found\n", __FUNCTION__);
483                         return page;
484                 }
485         page = kvm_mmu_alloc_page(vcpu, parent_pte);
486         if (!page)
487                 return page;
488         pgprintk("%s: adding gfn %lx role %x\n", __FUNCTION__, gfn, role.word);
489         page->gfn = gfn;
490         page->role = role;
491         hlist_add_head(&page->hash_link, bucket);
492         if (!metaphysical)
493                 rmap_write_protect(vcpu->kvm, gfn);
494         return page;
495 }
496
497 static void kvm_mmu_page_unlink_children(struct kvm_vcpu *vcpu,
498                                          struct kvm_mmu_page *page)
499 {
500         unsigned i;
501         u64 *pt;
502         u64 ent;
503
504         pt = __va(page->page_hpa);
505
506         if (page->role.level == PT_PAGE_TABLE_LEVEL) {
507                 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
508                         if (pt[i] & PT_PRESENT_MASK)
509                                 rmap_remove(vcpu->kvm, &pt[i]);
510                         pt[i] = 0;
511                 }
512                 return;
513         }
514
515         for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
516                 ent = pt[i];
517
518                 pt[i] = 0;
519                 if (!(ent & PT_PRESENT_MASK))
520                         continue;
521                 ent &= PT64_BASE_ADDR_MASK;
522                 mmu_page_remove_parent_pte(page_header(ent), &pt[i]);
523         }
524 }
525
526 static void kvm_mmu_put_page(struct kvm_vcpu *vcpu,
527                              struct kvm_mmu_page *page,
528                              u64 *parent_pte)
529 {
530         mmu_page_remove_parent_pte(page, parent_pte);
531 }
532
533 static void kvm_mmu_zap_page(struct kvm_vcpu *vcpu,
534                              struct kvm_mmu_page *page)
535 {
536         u64 *parent_pte;
537
538         while (page->multimapped || page->parent_pte) {
539                 if (!page->multimapped)
540                         parent_pte = page->parent_pte;
541                 else {
542                         struct kvm_pte_chain *chain;
543
544                         chain = container_of(page->parent_ptes.first,
545                                              struct kvm_pte_chain, link);
546                         parent_pte = chain->parent_ptes[0];
547                 }
548                 BUG_ON(!parent_pte);
549                 kvm_mmu_put_page(vcpu, page, parent_pte);
550                 *parent_pte = 0;
551         }
552         kvm_mmu_page_unlink_children(vcpu, page);
553         if (!page->root_count) {
554                 hlist_del(&page->hash_link);
555                 kvm_mmu_free_page(vcpu, page->page_hpa);
556         } else {
557                 list_del(&page->link);
558                 list_add(&page->link, &vcpu->kvm->active_mmu_pages);
559         }
560 }
561
562 static int kvm_mmu_unprotect_page(struct kvm_vcpu *vcpu, gfn_t gfn)
563 {
564         unsigned index;
565         struct hlist_head *bucket;
566         struct kvm_mmu_page *page;
567         struct hlist_node *node, *n;
568         int r;
569
570         pgprintk("%s: looking for gfn %lx\n", __FUNCTION__, gfn);
571         r = 0;
572         index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
573         bucket = &vcpu->kvm->mmu_page_hash[index];
574         hlist_for_each_entry_safe(page, node, n, bucket, hash_link)
575                 if (page->gfn == gfn && !page->role.metaphysical) {
576                         pgprintk("%s: gfn %lx role %x\n", __FUNCTION__, gfn,
577                                  page->role.word);
578                         kvm_mmu_zap_page(vcpu, page);
579                         r = 1;
580                 }
581         return r;
582 }
583
584 static void page_header_update_slot(struct kvm *kvm, void *pte, gpa_t gpa)
585 {
586         int slot = memslot_id(kvm, gfn_to_memslot(kvm, gpa >> PAGE_SHIFT));
587         struct kvm_mmu_page *page_head = page_header(__pa(pte));
588
589         __set_bit(slot, &page_head->slot_bitmap);
590 }
591
592 hpa_t safe_gpa_to_hpa(struct kvm_vcpu *vcpu, gpa_t gpa)
593 {
594         hpa_t hpa = gpa_to_hpa(vcpu, gpa);
595
596         return is_error_hpa(hpa) ? bad_page_address | (gpa & ~PAGE_MASK): hpa;
597 }
598
599 hpa_t gpa_to_hpa(struct kvm_vcpu *vcpu, gpa_t gpa)
600 {
601         struct kvm_memory_slot *slot;
602         struct page *page;
603
604         ASSERT((gpa & HPA_ERR_MASK) == 0);
605         slot = gfn_to_memslot(vcpu->kvm, gpa >> PAGE_SHIFT);
606         if (!slot)
607                 return gpa | HPA_ERR_MASK;
608         page = gfn_to_page(slot, gpa >> PAGE_SHIFT);
609         return ((hpa_t)page_to_pfn(page) << PAGE_SHIFT)
610                 | (gpa & (PAGE_SIZE-1));
611 }
612
613 hpa_t gva_to_hpa(struct kvm_vcpu *vcpu, gva_t gva)
614 {
615         gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, gva);
616
617         if (gpa == UNMAPPED_GVA)
618                 return UNMAPPED_GVA;
619         return gpa_to_hpa(vcpu, gpa);
620 }
621
622 static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
623 {
624 }
625
626 static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, hpa_t p)
627 {
628         int level = PT32E_ROOT_LEVEL;
629         hpa_t table_addr = vcpu->mmu.root_hpa;
630
631         for (; ; level--) {
632                 u32 index = PT64_INDEX(v, level);
633                 u64 *table;
634                 u64 pte;
635
636                 ASSERT(VALID_PAGE(table_addr));
637                 table = __va(table_addr);
638
639                 if (level == 1) {
640                         pte = table[index];
641                         if (is_present_pte(pte) && is_writeble_pte(pte))
642                                 return 0;
643                         mark_page_dirty(vcpu->kvm, v >> PAGE_SHIFT);
644                         page_header_update_slot(vcpu->kvm, table, v);
645                         table[index] = p | PT_PRESENT_MASK | PT_WRITABLE_MASK |
646                                                                 PT_USER_MASK;
647                         rmap_add(vcpu->kvm, &table[index]);
648                         return 0;
649                 }
650
651                 if (table[index] == 0) {
652                         struct kvm_mmu_page *new_table;
653                         gfn_t pseudo_gfn;
654
655                         pseudo_gfn = (v & PT64_DIR_BASE_ADDR_MASK)
656                                 >> PAGE_SHIFT;
657                         new_table = kvm_mmu_get_page(vcpu, pseudo_gfn,
658                                                      v, level - 1,
659                                                      1, &table[index]);
660                         if (!new_table) {
661                                 pgprintk("nonpaging_map: ENOMEM\n");
662                                 return -ENOMEM;
663                         }
664
665                         table[index] = new_table->page_hpa | PT_PRESENT_MASK
666                                 | PT_WRITABLE_MASK | PT_USER_MASK;
667                 }
668                 table_addr = table[index] & PT64_BASE_ADDR_MASK;
669         }
670 }
671
672 static void mmu_free_roots(struct kvm_vcpu *vcpu)
673 {
674         int i;
675         struct kvm_mmu_page *page;
676
677 #ifdef CONFIG_X86_64
678         if (vcpu->mmu.shadow_root_level == PT64_ROOT_LEVEL) {
679                 hpa_t root = vcpu->mmu.root_hpa;
680
681                 ASSERT(VALID_PAGE(root));
682                 page = page_header(root);
683                 --page->root_count;
684                 vcpu->mmu.root_hpa = INVALID_PAGE;
685                 return;
686         }
687 #endif
688         for (i = 0; i < 4; ++i) {
689                 hpa_t root = vcpu->mmu.pae_root[i];
690
691                 ASSERT(VALID_PAGE(root));
692                 root &= PT64_BASE_ADDR_MASK;
693                 page = page_header(root);
694                 --page->root_count;
695                 vcpu->mmu.pae_root[i] = INVALID_PAGE;
696         }
697         vcpu->mmu.root_hpa = INVALID_PAGE;
698 }
699
700 static void mmu_alloc_roots(struct kvm_vcpu *vcpu)
701 {
702         int i;
703         gfn_t root_gfn;
704         struct kvm_mmu_page *page;
705
706         root_gfn = vcpu->cr3 >> PAGE_SHIFT;
707
708 #ifdef CONFIG_X86_64
709         if (vcpu->mmu.shadow_root_level == PT64_ROOT_LEVEL) {
710                 hpa_t root = vcpu->mmu.root_hpa;
711
712                 ASSERT(!VALID_PAGE(root));
713                 root = kvm_mmu_get_page(vcpu, root_gfn, 0,
714                                         PT64_ROOT_LEVEL, 0, NULL)->page_hpa;
715                 page = page_header(root);
716                 ++page->root_count;
717                 vcpu->mmu.root_hpa = root;
718                 return;
719         }
720 #endif
721         for (i = 0; i < 4; ++i) {
722                 hpa_t root = vcpu->mmu.pae_root[i];
723
724                 ASSERT(!VALID_PAGE(root));
725                 if (vcpu->mmu.root_level == PT32E_ROOT_LEVEL)
726                         root_gfn = vcpu->pdptrs[i] >> PAGE_SHIFT;
727                 else if (vcpu->mmu.root_level == 0)
728                         root_gfn = 0;
729                 root = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
730                                         PT32_ROOT_LEVEL, !is_paging(vcpu),
731                                         NULL)->page_hpa;
732                 page = page_header(root);
733                 ++page->root_count;
734                 vcpu->mmu.pae_root[i] = root | PT_PRESENT_MASK;
735         }
736         vcpu->mmu.root_hpa = __pa(vcpu->mmu.pae_root);
737 }
738
739 static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr)
740 {
741         return vaddr;
742 }
743
744 static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
745                                u32 error_code)
746 {
747         gpa_t addr = gva;
748         hpa_t paddr;
749
750         ASSERT(vcpu);
751         ASSERT(VALID_PAGE(vcpu->mmu.root_hpa));
752
753
754         paddr = gpa_to_hpa(vcpu , addr & PT64_BASE_ADDR_MASK);
755
756         if (is_error_hpa(paddr))
757                 return 1;
758
759         return nonpaging_map(vcpu, addr & PAGE_MASK, paddr);
760 }
761
762 static void nonpaging_free(struct kvm_vcpu *vcpu)
763 {
764         mmu_free_roots(vcpu);
765 }
766
767 static int nonpaging_init_context(struct kvm_vcpu *vcpu)
768 {
769         struct kvm_mmu *context = &vcpu->mmu;
770
771         context->new_cr3 = nonpaging_new_cr3;
772         context->page_fault = nonpaging_page_fault;
773         context->gva_to_gpa = nonpaging_gva_to_gpa;
774         context->free = nonpaging_free;
775         context->root_level = 0;
776         context->shadow_root_level = PT32E_ROOT_LEVEL;
777         mmu_alloc_roots(vcpu);
778         ASSERT(VALID_PAGE(context->root_hpa));
779         kvm_arch_ops->set_cr3(vcpu, context->root_hpa);
780         return 0;
781 }
782
783 static void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
784 {
785         ++kvm_stat.tlb_flush;
786         kvm_arch_ops->tlb_flush(vcpu);
787 }
788
789 static void paging_new_cr3(struct kvm_vcpu *vcpu)
790 {
791         pgprintk("%s: cr3 %lx\n", __FUNCTION__, vcpu->cr3);
792         mmu_free_roots(vcpu);
793         mmu_alloc_roots(vcpu);
794         kvm_mmu_flush_tlb(vcpu);
795         kvm_arch_ops->set_cr3(vcpu, vcpu->mmu.root_hpa);
796 }
797
798 static void mark_pagetable_nonglobal(void *shadow_pte)
799 {
800         page_header(__pa(shadow_pte))->global = 0;
801 }
802
803 static inline void set_pte_common(struct kvm_vcpu *vcpu,
804                              u64 *shadow_pte,
805                              gpa_t gaddr,
806                              int dirty,
807                              u64 access_bits,
808                              gfn_t gfn)
809 {
810         hpa_t paddr;
811
812         *shadow_pte |= access_bits << PT_SHADOW_BITS_OFFSET;
813         if (!dirty)
814                 access_bits &= ~PT_WRITABLE_MASK;
815
816         paddr = gpa_to_hpa(vcpu, gaddr & PT64_BASE_ADDR_MASK);
817
818         *shadow_pte |= access_bits;
819
820         if (!(*shadow_pte & PT_GLOBAL_MASK))
821                 mark_pagetable_nonglobal(shadow_pte);
822
823         if (is_error_hpa(paddr)) {
824                 *shadow_pte |= gaddr;
825                 *shadow_pte |= PT_SHADOW_IO_MARK;
826                 *shadow_pte &= ~PT_PRESENT_MASK;
827                 return;
828         }
829
830         *shadow_pte |= paddr;
831
832         if (access_bits & PT_WRITABLE_MASK) {
833                 struct kvm_mmu_page *shadow;
834
835                 shadow = kvm_mmu_lookup_page(vcpu, gfn);
836                 if (shadow) {
837                         pgprintk("%s: found shadow page for %lx, marking ro\n",
838                                  __FUNCTION__, gfn);
839                         access_bits &= ~PT_WRITABLE_MASK;
840                         *shadow_pte &= ~PT_WRITABLE_MASK;
841                 }
842         }
843
844         if (access_bits & PT_WRITABLE_MASK)
845                 mark_page_dirty(vcpu->kvm, gaddr >> PAGE_SHIFT);
846
847         page_header_update_slot(vcpu->kvm, shadow_pte, gaddr);
848         rmap_add(vcpu->kvm, shadow_pte);
849 }
850
851 static void inject_page_fault(struct kvm_vcpu *vcpu,
852                               u64 addr,
853                               u32 err_code)
854 {
855         kvm_arch_ops->inject_page_fault(vcpu, addr, err_code);
856 }
857
858 static inline int fix_read_pf(u64 *shadow_ent)
859 {
860         if ((*shadow_ent & PT_SHADOW_USER_MASK) &&
861             !(*shadow_ent & PT_USER_MASK)) {
862                 /*
863                  * If supervisor write protect is disabled, we shadow kernel
864                  * pages as user pages so we can trap the write access.
865                  */
866                 *shadow_ent |= PT_USER_MASK;
867                 *shadow_ent &= ~PT_WRITABLE_MASK;
868
869                 return 1;
870
871         }
872         return 0;
873 }
874
875 static int may_access(u64 pte, int write, int user)
876 {
877
878         if (user && !(pte & PT_USER_MASK))
879                 return 0;
880         if (write && !(pte & PT_WRITABLE_MASK))
881                 return 0;
882         return 1;
883 }
884
885 static void paging_free(struct kvm_vcpu *vcpu)
886 {
887         nonpaging_free(vcpu);
888 }
889
890 #define PTTYPE 64
891 #include "paging_tmpl.h"
892 #undef PTTYPE
893
894 #define PTTYPE 32
895 #include "paging_tmpl.h"
896 #undef PTTYPE
897
898 static int paging64_init_context_common(struct kvm_vcpu *vcpu, int level)
899 {
900         struct kvm_mmu *context = &vcpu->mmu;
901
902         ASSERT(is_pae(vcpu));
903         context->new_cr3 = paging_new_cr3;
904         context->page_fault = paging64_page_fault;
905         context->gva_to_gpa = paging64_gva_to_gpa;
906         context->free = paging_free;
907         context->root_level = level;
908         context->shadow_root_level = level;
909         mmu_alloc_roots(vcpu);
910         ASSERT(VALID_PAGE(context->root_hpa));
911         kvm_arch_ops->set_cr3(vcpu, context->root_hpa |
912                     (vcpu->cr3 & (CR3_PCD_MASK | CR3_WPT_MASK)));
913         return 0;
914 }
915
916 static int paging64_init_context(struct kvm_vcpu *vcpu)
917 {
918         return paging64_init_context_common(vcpu, PT64_ROOT_LEVEL);
919 }
920
921 static int paging32_init_context(struct kvm_vcpu *vcpu)
922 {
923         struct kvm_mmu *context = &vcpu->mmu;
924
925         context->new_cr3 = paging_new_cr3;
926         context->page_fault = paging32_page_fault;
927         context->gva_to_gpa = paging32_gva_to_gpa;
928         context->free = paging_free;
929         context->root_level = PT32_ROOT_LEVEL;
930         context->shadow_root_level = PT32E_ROOT_LEVEL;
931         mmu_alloc_roots(vcpu);
932         ASSERT(VALID_PAGE(context->root_hpa));
933         kvm_arch_ops->set_cr3(vcpu, context->root_hpa |
934                     (vcpu->cr3 & (CR3_PCD_MASK | CR3_WPT_MASK)));
935         return 0;
936 }
937
938 static int paging32E_init_context(struct kvm_vcpu *vcpu)
939 {
940         return paging64_init_context_common(vcpu, PT32E_ROOT_LEVEL);
941 }
942
943 static int init_kvm_mmu(struct kvm_vcpu *vcpu)
944 {
945         ASSERT(vcpu);
946         ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));
947
948         if (!is_paging(vcpu))
949                 return nonpaging_init_context(vcpu);
950         else if (is_long_mode(vcpu))
951                 return paging64_init_context(vcpu);
952         else if (is_pae(vcpu))
953                 return paging32E_init_context(vcpu);
954         else
955                 return paging32_init_context(vcpu);
956 }
957
958 static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
959 {
960         ASSERT(vcpu);
961         if (VALID_PAGE(vcpu->mmu.root_hpa)) {
962                 vcpu->mmu.free(vcpu);
963                 vcpu->mmu.root_hpa = INVALID_PAGE;
964         }
965 }
966
967 int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
968 {
969         destroy_kvm_mmu(vcpu);
970         return init_kvm_mmu(vcpu);
971 }
972
973 void kvm_mmu_pre_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes)
974 {
975         gfn_t gfn = gpa >> PAGE_SHIFT;
976         struct kvm_mmu_page *page;
977         struct kvm_mmu_page *child;
978         struct hlist_node *node, *n;
979         struct hlist_head *bucket;
980         unsigned index;
981         u64 *spte;
982         u64 pte;
983         unsigned offset = offset_in_page(gpa);
984         unsigned pte_size;
985         unsigned page_offset;
986         unsigned misaligned;
987         int level;
988         int flooded = 0;
989
990         pgprintk("%s: gpa %llx bytes %d\n", __FUNCTION__, gpa, bytes);
991         if (gfn == vcpu->last_pt_write_gfn) {
992                 ++vcpu->last_pt_write_count;
993                 if (vcpu->last_pt_write_count >= 3)
994                         flooded = 1;
995         } else {
996                 vcpu->last_pt_write_gfn = gfn;
997                 vcpu->last_pt_write_count = 1;
998         }
999         index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
1000         bucket = &vcpu->kvm->mmu_page_hash[index];
1001         hlist_for_each_entry_safe(page, node, n, bucket, hash_link) {
1002                 if (page->gfn != gfn || page->role.metaphysical)
1003                         continue;
1004                 pte_size = page->role.glevels == PT32_ROOT_LEVEL ? 4 : 8;
1005                 misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
1006                 if (misaligned || flooded) {
1007                         /*
1008                          * Misaligned accesses are too much trouble to fix
1009                          * up; also, they usually indicate a page is not used
1010                          * as a page table.
1011                          *
1012                          * If we're seeing too many writes to a page,
1013                          * it may no longer be a page table, or we may be
1014                          * forking, in which case it is better to unmap the
1015                          * page.
1016                          */
1017                         pgprintk("misaligned: gpa %llx bytes %d role %x\n",
1018                                  gpa, bytes, page->role.word);
1019                         kvm_mmu_zap_page(vcpu, page);
1020                         continue;
1021                 }
1022                 page_offset = offset;
1023                 level = page->role.level;
1024                 if (page->role.glevels == PT32_ROOT_LEVEL) {
1025                         page_offset <<= 1;          /* 32->64 */
1026                         page_offset &= ~PAGE_MASK;
1027                 }
1028                 spte = __va(page->page_hpa);
1029                 spte += page_offset / sizeof(*spte);
1030                 pte = *spte;
1031                 if (is_present_pte(pte)) {
1032                         if (level == PT_PAGE_TABLE_LEVEL)
1033                                 rmap_remove(vcpu->kvm, spte);
1034                         else {
1035                                 child = page_header(pte & PT64_BASE_ADDR_MASK);
1036                                 mmu_page_remove_parent_pte(child, spte);
1037                         }
1038                 }
1039                 *spte = 0;
1040         }
1041 }
1042
1043 void kvm_mmu_post_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes)
1044 {
1045 }
1046
1047 int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
1048 {
1049         gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, gva);
1050
1051         return kvm_mmu_unprotect_page(vcpu, gpa >> PAGE_SHIFT);
1052 }
1053
1054 void kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
1055 {
1056         while (vcpu->kvm->n_free_mmu_pages < KVM_REFILL_PAGES) {
1057                 struct kvm_mmu_page *page;
1058
1059                 page = container_of(vcpu->kvm->active_mmu_pages.prev,
1060                                     struct kvm_mmu_page, link);
1061                 kvm_mmu_zap_page(vcpu, page);
1062         }
1063 }
1064 EXPORT_SYMBOL_GPL(kvm_mmu_free_some_pages);
1065
1066 static void free_mmu_pages(struct kvm_vcpu *vcpu)
1067 {
1068         struct kvm_mmu_page *page;
1069
1070         while (!list_empty(&vcpu->kvm->active_mmu_pages)) {
1071                 page = container_of(vcpu->kvm->active_mmu_pages.next,
1072                                     struct kvm_mmu_page, link);
1073                 kvm_mmu_zap_page(vcpu, page);
1074         }
1075         while (!list_empty(&vcpu->free_pages)) {
1076                 page = list_entry(vcpu->free_pages.next,
1077                                   struct kvm_mmu_page, link);
1078                 list_del(&page->link);
1079                 __free_page(pfn_to_page(page->page_hpa >> PAGE_SHIFT));
1080                 page->page_hpa = INVALID_PAGE;
1081         }
1082         free_page((unsigned long)vcpu->mmu.pae_root);
1083 }
1084
1085 static int alloc_mmu_pages(struct kvm_vcpu *vcpu)
1086 {
1087         struct page *page;
1088         int i;
1089
1090         ASSERT(vcpu);
1091
1092         for (i = 0; i < KVM_NUM_MMU_PAGES; i++) {
1093                 struct kvm_mmu_page *page_header = &vcpu->page_header_buf[i];
1094
1095                 INIT_LIST_HEAD(&page_header->link);
1096                 if ((page = alloc_page(GFP_KERNEL)) == NULL)
1097                         goto error_1;
1098                 page->private = (unsigned long)page_header;
1099                 page_header->page_hpa = (hpa_t)page_to_pfn(page) << PAGE_SHIFT;
1100                 memset(__va(page_header->page_hpa), 0, PAGE_SIZE);
1101                 list_add(&page_header->link, &vcpu->free_pages);
1102                 ++vcpu->kvm->n_free_mmu_pages;
1103         }
1104
1105         /*
1106          * When emulating 32-bit mode, cr3 is only 32 bits even on x86_64.
1107          * Therefore we need to allocate shadow page tables in the first
1108          * 4GB of memory, which happens to fit the DMA32 zone.
1109          */
1110         page = alloc_page(GFP_KERNEL | __GFP_DMA32);
1111         if (!page)
1112                 goto error_1;
1113         vcpu->mmu.pae_root = page_address(page);
1114         for (i = 0; i < 4; ++i)
1115                 vcpu->mmu.pae_root[i] = INVALID_PAGE;
1116
1117         return 0;
1118
1119 error_1:
1120         free_mmu_pages(vcpu);
1121         return -ENOMEM;
1122 }
1123
1124 int kvm_mmu_create(struct kvm_vcpu *vcpu)
1125 {
1126         ASSERT(vcpu);
1127         ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));
1128         ASSERT(list_empty(&vcpu->free_pages));
1129
1130         return alloc_mmu_pages(vcpu);
1131 }
1132
1133 int kvm_mmu_setup(struct kvm_vcpu *vcpu)
1134 {
1135         ASSERT(vcpu);
1136         ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));
1137         ASSERT(!list_empty(&vcpu->free_pages));
1138
1139         return init_kvm_mmu(vcpu);
1140 }
1141
1142 void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
1143 {
1144         ASSERT(vcpu);
1145
1146         destroy_kvm_mmu(vcpu);
1147         free_mmu_pages(vcpu);
1148 }
1149
1150 void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
1151 {
1152         struct kvm_mmu_page *page;
1153
1154         list_for_each_entry(page, &kvm->active_mmu_pages, link) {
1155                 int i;
1156                 u64 *pt;
1157
1158                 if (!test_bit(slot, &page->slot_bitmap))
1159                         continue;
1160
1161                 pt = __va(page->page_hpa);
1162                 for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
1163                         /* avoid RMW */
1164                         if (pt[i] & PT_WRITABLE_MASK) {
1165                                 rmap_remove(kvm, &pt[i]);
1166                                 pt[i] &= ~PT_WRITABLE_MASK;
1167                         }
1168         }
1169 }