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KVM: MMU: optimize set_spte for page sync
[deliverable/linux.git] / arch / x86 / 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 "mmu.h"
21
22 #include <linux/kvm_host.h>
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 #include <linux/swap.h>
29 #include <linux/hugetlb.h>
30 #include <linux/compiler.h>
31
32 #include <asm/page.h>
33 #include <asm/cmpxchg.h>
34 #include <asm/io.h>
35 #include <asm/vmx.h>
36
37 /*
38 * When setting this variable to true it enables Two-Dimensional-Paging
39 * where the hardware walks 2 page tables:
40 * 1. the guest-virtual to guest-physical
41 * 2. while doing 1. it walks guest-physical to host-physical
42 * If the hardware supports that we don't need to do shadow paging.
43 */
44 bool tdp_enabled = false;
45
46 #undef MMU_DEBUG
47
48 #undef AUDIT
49
50 #ifdef AUDIT
51 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg);
52 #else
53 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg) {}
54 #endif
55
56 #ifdef MMU_DEBUG
57
58 #define pgprintk(x...) do { if (dbg) printk(x); } while (0)
59 #define rmap_printk(x...) do { if (dbg) printk(x); } while (0)
60
61 #else
62
63 #define pgprintk(x...) do { } while (0)
64 #define rmap_printk(x...) do { } while (0)
65
66 #endif
67
68 #if defined(MMU_DEBUG) || defined(AUDIT)
69 static int dbg = 0;
70 module_param(dbg, bool, 0644);
71 #endif
72
73 static int oos_shadow = 1;
74 module_param(oos_shadow, bool, 0644);
75
76 #ifndef MMU_DEBUG
77 #define ASSERT(x) do { } while (0)
78 #else
79 #define ASSERT(x) \
80 if (!(x)) { \
81 printk(KERN_WARNING "assertion failed %s:%d: %s\n", \
82 __FILE__, __LINE__, #x); \
83 }
84 #endif
85
86 #define PT_FIRST_AVAIL_BITS_SHIFT 9
87 #define PT64_SECOND_AVAIL_BITS_SHIFT 52
88
89 #define VALID_PAGE(x) ((x) != INVALID_PAGE)
90
91 #define PT64_LEVEL_BITS 9
92
93 #define PT64_LEVEL_SHIFT(level) \
94 (PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS)
95
96 #define PT64_LEVEL_MASK(level) \
97 (((1ULL << PT64_LEVEL_BITS) - 1) << PT64_LEVEL_SHIFT(level))
98
99 #define PT64_INDEX(address, level)\
100 (((address) >> PT64_LEVEL_SHIFT(level)) & ((1 << PT64_LEVEL_BITS) - 1))
101
102
103 #define PT32_LEVEL_BITS 10
104
105 #define PT32_LEVEL_SHIFT(level) \
106 (PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS)
107
108 #define PT32_LEVEL_MASK(level) \
109 (((1ULL << PT32_LEVEL_BITS) - 1) << PT32_LEVEL_SHIFT(level))
110
111 #define PT32_INDEX(address, level)\
112 (((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))
113
114
115 #define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))
116 #define PT64_DIR_BASE_ADDR_MASK \
117 (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))
118
119 #define PT32_BASE_ADDR_MASK PAGE_MASK
120 #define PT32_DIR_BASE_ADDR_MASK \
121 (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
122
123 #define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK \
124 | PT64_NX_MASK)
125
126 #define PFERR_PRESENT_MASK (1U << 0)
127 #define PFERR_WRITE_MASK (1U << 1)
128 #define PFERR_USER_MASK (1U << 2)
129 #define PFERR_FETCH_MASK (1U << 4)
130
131 #define PT_DIRECTORY_LEVEL 2
132 #define PT_PAGE_TABLE_LEVEL 1
133
134 #define RMAP_EXT 4
135
136 #define ACC_EXEC_MASK 1
137 #define ACC_WRITE_MASK PT_WRITABLE_MASK
138 #define ACC_USER_MASK PT_USER_MASK
139 #define ACC_ALL (ACC_EXEC_MASK | ACC_WRITE_MASK | ACC_USER_MASK)
140
141 #define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)
142
143 struct kvm_rmap_desc {
144 u64 *shadow_ptes[RMAP_EXT];
145 struct kvm_rmap_desc *more;
146 };
147
148 struct kvm_shadow_walk {
149 int (*entry)(struct kvm_shadow_walk *walk, struct kvm_vcpu *vcpu,
150 u64 addr, u64 *spte, int level);
151 };
152
153 struct kvm_unsync_walk {
154 int (*entry) (struct kvm_mmu_page *sp, struct kvm_unsync_walk *walk);
155 };
156
157 typedef int (*mmu_parent_walk_fn) (struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp);
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 static u64 __read_mostly shadow_base_present_pte;
166 static u64 __read_mostly shadow_nx_mask;
167 static u64 __read_mostly shadow_x_mask; /* mutual exclusive with nx_mask */
168 static u64 __read_mostly shadow_user_mask;
169 static u64 __read_mostly shadow_accessed_mask;
170 static u64 __read_mostly shadow_dirty_mask;
171 static u64 __read_mostly shadow_mt_mask;
172
173 void kvm_mmu_set_nonpresent_ptes(u64 trap_pte, u64 notrap_pte)
174 {
175 shadow_trap_nonpresent_pte = trap_pte;
176 shadow_notrap_nonpresent_pte = notrap_pte;
177 }
178 EXPORT_SYMBOL_GPL(kvm_mmu_set_nonpresent_ptes);
179
180 void kvm_mmu_set_base_ptes(u64 base_pte)
181 {
182 shadow_base_present_pte = base_pte;
183 }
184 EXPORT_SYMBOL_GPL(kvm_mmu_set_base_ptes);
185
186 void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
187 u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 mt_mask)
188 {
189 shadow_user_mask = user_mask;
190 shadow_accessed_mask = accessed_mask;
191 shadow_dirty_mask = dirty_mask;
192 shadow_nx_mask = nx_mask;
193 shadow_x_mask = x_mask;
194 shadow_mt_mask = mt_mask;
195 }
196 EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);
197
198 static int is_write_protection(struct kvm_vcpu *vcpu)
199 {
200 return vcpu->arch.cr0 & X86_CR0_WP;
201 }
202
203 static int is_cpuid_PSE36(void)
204 {
205 return 1;
206 }
207
208 static int is_nx(struct kvm_vcpu *vcpu)
209 {
210 return vcpu->arch.shadow_efer & EFER_NX;
211 }
212
213 static int is_present_pte(unsigned long pte)
214 {
215 return pte & PT_PRESENT_MASK;
216 }
217
218 static int is_shadow_present_pte(u64 pte)
219 {
220 return pte != shadow_trap_nonpresent_pte
221 && pte != shadow_notrap_nonpresent_pte;
222 }
223
224 static int is_large_pte(u64 pte)
225 {
226 return pte & PT_PAGE_SIZE_MASK;
227 }
228
229 static int is_writeble_pte(unsigned long pte)
230 {
231 return pte & PT_WRITABLE_MASK;
232 }
233
234 static int is_dirty_pte(unsigned long pte)
235 {
236 return pte & shadow_dirty_mask;
237 }
238
239 static int is_rmap_pte(u64 pte)
240 {
241 return is_shadow_present_pte(pte);
242 }
243
244 static pfn_t spte_to_pfn(u64 pte)
245 {
246 return (pte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
247 }
248
249 static gfn_t pse36_gfn_delta(u32 gpte)
250 {
251 int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT;
252
253 return (gpte & PT32_DIR_PSE36_MASK) << shift;
254 }
255
256 static void set_shadow_pte(u64 *sptep, u64 spte)
257 {
258 #ifdef CONFIG_X86_64
259 set_64bit((unsigned long *)sptep, spte);
260 #else
261 set_64bit((unsigned long long *)sptep, spte);
262 #endif
263 }
264
265 static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
266 struct kmem_cache *base_cache, int min)
267 {
268 void *obj;
269
270 if (cache->nobjs >= min)
271 return 0;
272 while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
273 obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
274 if (!obj)
275 return -ENOMEM;
276 cache->objects[cache->nobjs++] = obj;
277 }
278 return 0;
279 }
280
281 static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
282 {
283 while (mc->nobjs)
284 kfree(mc->objects[--mc->nobjs]);
285 }
286
287 static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
288 int min)
289 {
290 struct page *page;
291
292 if (cache->nobjs >= min)
293 return 0;
294 while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
295 page = alloc_page(GFP_KERNEL);
296 if (!page)
297 return -ENOMEM;
298 set_page_private(page, 0);
299 cache->objects[cache->nobjs++] = page_address(page);
300 }
301 return 0;
302 }
303
304 static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
305 {
306 while (mc->nobjs)
307 free_page((unsigned long)mc->objects[--mc->nobjs]);
308 }
309
310 static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
311 {
312 int r;
313
314 r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_chain_cache,
315 pte_chain_cache, 4);
316 if (r)
317 goto out;
318 r = mmu_topup_memory_cache(&vcpu->arch.mmu_rmap_desc_cache,
319 rmap_desc_cache, 4);
320 if (r)
321 goto out;
322 r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
323 if (r)
324 goto out;
325 r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
326 mmu_page_header_cache, 4);
327 out:
328 return r;
329 }
330
331 static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
332 {
333 mmu_free_memory_cache(&vcpu->arch.mmu_pte_chain_cache);
334 mmu_free_memory_cache(&vcpu->arch.mmu_rmap_desc_cache);
335 mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache);
336 mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache);
337 }
338
339 static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc,
340 size_t size)
341 {
342 void *p;
343
344 BUG_ON(!mc->nobjs);
345 p = mc->objects[--mc->nobjs];
346 memset(p, 0, size);
347 return p;
348 }
349
350 static struct kvm_pte_chain *mmu_alloc_pte_chain(struct kvm_vcpu *vcpu)
351 {
352 return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_chain_cache,
353 sizeof(struct kvm_pte_chain));
354 }
355
356 static void mmu_free_pte_chain(struct kvm_pte_chain *pc)
357 {
358 kfree(pc);
359 }
360
361 static struct kvm_rmap_desc *mmu_alloc_rmap_desc(struct kvm_vcpu *vcpu)
362 {
363 return mmu_memory_cache_alloc(&vcpu->arch.mmu_rmap_desc_cache,
364 sizeof(struct kvm_rmap_desc));
365 }
366
367 static void mmu_free_rmap_desc(struct kvm_rmap_desc *rd)
368 {
369 kfree(rd);
370 }
371
372 /*
373 * Return the pointer to the largepage write count for a given
374 * gfn, handling slots that are not large page aligned.
375 */
376 static int *slot_largepage_idx(gfn_t gfn, struct kvm_memory_slot *slot)
377 {
378 unsigned long idx;
379
380 idx = (gfn / KVM_PAGES_PER_HPAGE) -
381 (slot->base_gfn / KVM_PAGES_PER_HPAGE);
382 return &slot->lpage_info[idx].write_count;
383 }
384
385 static void account_shadowed(struct kvm *kvm, gfn_t gfn)
386 {
387 int *write_count;
388
389 gfn = unalias_gfn(kvm, gfn);
390 write_count = slot_largepage_idx(gfn,
391 gfn_to_memslot_unaliased(kvm, gfn));
392 *write_count += 1;
393 }
394
395 static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn)
396 {
397 int *write_count;
398
399 gfn = unalias_gfn(kvm, gfn);
400 write_count = slot_largepage_idx(gfn,
401 gfn_to_memslot_unaliased(kvm, gfn));
402 *write_count -= 1;
403 WARN_ON(*write_count < 0);
404 }
405
406 static int has_wrprotected_page(struct kvm *kvm, gfn_t gfn)
407 {
408 struct kvm_memory_slot *slot;
409 int *largepage_idx;
410
411 gfn = unalias_gfn(kvm, gfn);
412 slot = gfn_to_memslot_unaliased(kvm, gfn);
413 if (slot) {
414 largepage_idx = slot_largepage_idx(gfn, slot);
415 return *largepage_idx;
416 }
417
418 return 1;
419 }
420
421 static int host_largepage_backed(struct kvm *kvm, gfn_t gfn)
422 {
423 struct vm_area_struct *vma;
424 unsigned long addr;
425 int ret = 0;
426
427 addr = gfn_to_hva(kvm, gfn);
428 if (kvm_is_error_hva(addr))
429 return ret;
430
431 down_read(&current->mm->mmap_sem);
432 vma = find_vma(current->mm, addr);
433 if (vma && is_vm_hugetlb_page(vma))
434 ret = 1;
435 up_read(&current->mm->mmap_sem);
436
437 return ret;
438 }
439
440 static int is_largepage_backed(struct kvm_vcpu *vcpu, gfn_t large_gfn)
441 {
442 struct kvm_memory_slot *slot;
443
444 if (has_wrprotected_page(vcpu->kvm, large_gfn))
445 return 0;
446
447 if (!host_largepage_backed(vcpu->kvm, large_gfn))
448 return 0;
449
450 slot = gfn_to_memslot(vcpu->kvm, large_gfn);
451 if (slot && slot->dirty_bitmap)
452 return 0;
453
454 return 1;
455 }
456
457 /*
458 * Take gfn and return the reverse mapping to it.
459 * Note: gfn must be unaliased before this function get called
460 */
461
462 static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int lpage)
463 {
464 struct kvm_memory_slot *slot;
465 unsigned long idx;
466
467 slot = gfn_to_memslot(kvm, gfn);
468 if (!lpage)
469 return &slot->rmap[gfn - slot->base_gfn];
470
471 idx = (gfn / KVM_PAGES_PER_HPAGE) -
472 (slot->base_gfn / KVM_PAGES_PER_HPAGE);
473
474 return &slot->lpage_info[idx].rmap_pde;
475 }
476
477 /*
478 * Reverse mapping data structures:
479 *
480 * If rmapp bit zero is zero, then rmapp point to the shadw page table entry
481 * that points to page_address(page).
482 *
483 * If rmapp bit zero is one, (then rmap & ~1) points to a struct kvm_rmap_desc
484 * containing more mappings.
485 */
486 static void rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn, int lpage)
487 {
488 struct kvm_mmu_page *sp;
489 struct kvm_rmap_desc *desc;
490 unsigned long *rmapp;
491 int i;
492
493 if (!is_rmap_pte(*spte))
494 return;
495 gfn = unalias_gfn(vcpu->kvm, gfn);
496 sp = page_header(__pa(spte));
497 sp->gfns[spte - sp->spt] = gfn;
498 rmapp = gfn_to_rmap(vcpu->kvm, gfn, lpage);
499 if (!*rmapp) {
500 rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte);
501 *rmapp = (unsigned long)spte;
502 } else if (!(*rmapp & 1)) {
503 rmap_printk("rmap_add: %p %llx 1->many\n", spte, *spte);
504 desc = mmu_alloc_rmap_desc(vcpu);
505 desc->shadow_ptes[0] = (u64 *)*rmapp;
506 desc->shadow_ptes[1] = spte;
507 *rmapp = (unsigned long)desc | 1;
508 } else {
509 rmap_printk("rmap_add: %p %llx many->many\n", spte, *spte);
510 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
511 while (desc->shadow_ptes[RMAP_EXT-1] && desc->more)
512 desc = desc->more;
513 if (desc->shadow_ptes[RMAP_EXT-1]) {
514 desc->more = mmu_alloc_rmap_desc(vcpu);
515 desc = desc->more;
516 }
517 for (i = 0; desc->shadow_ptes[i]; ++i)
518 ;
519 desc->shadow_ptes[i] = spte;
520 }
521 }
522
523 static void rmap_desc_remove_entry(unsigned long *rmapp,
524 struct kvm_rmap_desc *desc,
525 int i,
526 struct kvm_rmap_desc *prev_desc)
527 {
528 int j;
529
530 for (j = RMAP_EXT - 1; !desc->shadow_ptes[j] && j > i; --j)
531 ;
532 desc->shadow_ptes[i] = desc->shadow_ptes[j];
533 desc->shadow_ptes[j] = NULL;
534 if (j != 0)
535 return;
536 if (!prev_desc && !desc->more)
537 *rmapp = (unsigned long)desc->shadow_ptes[0];
538 else
539 if (prev_desc)
540 prev_desc->more = desc->more;
541 else
542 *rmapp = (unsigned long)desc->more | 1;
543 mmu_free_rmap_desc(desc);
544 }
545
546 static void rmap_remove(struct kvm *kvm, u64 *spte)
547 {
548 struct kvm_rmap_desc *desc;
549 struct kvm_rmap_desc *prev_desc;
550 struct kvm_mmu_page *sp;
551 pfn_t pfn;
552 unsigned long *rmapp;
553 int i;
554
555 if (!is_rmap_pte(*spte))
556 return;
557 sp = page_header(__pa(spte));
558 pfn = spte_to_pfn(*spte);
559 if (*spte & shadow_accessed_mask)
560 kvm_set_pfn_accessed(pfn);
561 if (is_writeble_pte(*spte))
562 kvm_release_pfn_dirty(pfn);
563 else
564 kvm_release_pfn_clean(pfn);
565 rmapp = gfn_to_rmap(kvm, sp->gfns[spte - sp->spt], is_large_pte(*spte));
566 if (!*rmapp) {
567 printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte);
568 BUG();
569 } else if (!(*rmapp & 1)) {
570 rmap_printk("rmap_remove: %p %llx 1->0\n", spte, *spte);
571 if ((u64 *)*rmapp != spte) {
572 printk(KERN_ERR "rmap_remove: %p %llx 1->BUG\n",
573 spte, *spte);
574 BUG();
575 }
576 *rmapp = 0;
577 } else {
578 rmap_printk("rmap_remove: %p %llx many->many\n", spte, *spte);
579 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
580 prev_desc = NULL;
581 while (desc) {
582 for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i)
583 if (desc->shadow_ptes[i] == spte) {
584 rmap_desc_remove_entry(rmapp,
585 desc, i,
586 prev_desc);
587 return;
588 }
589 prev_desc = desc;
590 desc = desc->more;
591 }
592 BUG();
593 }
594 }
595
596 static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte)
597 {
598 struct kvm_rmap_desc *desc;
599 struct kvm_rmap_desc *prev_desc;
600 u64 *prev_spte;
601 int i;
602
603 if (!*rmapp)
604 return NULL;
605 else if (!(*rmapp & 1)) {
606 if (!spte)
607 return (u64 *)*rmapp;
608 return NULL;
609 }
610 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
611 prev_desc = NULL;
612 prev_spte = NULL;
613 while (desc) {
614 for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i) {
615 if (prev_spte == spte)
616 return desc->shadow_ptes[i];
617 prev_spte = desc->shadow_ptes[i];
618 }
619 desc = desc->more;
620 }
621 return NULL;
622 }
623
624 static void rmap_write_protect(struct kvm *kvm, u64 gfn)
625 {
626 unsigned long *rmapp;
627 u64 *spte;
628 int write_protected = 0;
629
630 gfn = unalias_gfn(kvm, gfn);
631 rmapp = gfn_to_rmap(kvm, gfn, 0);
632
633 spte = rmap_next(kvm, rmapp, NULL);
634 while (spte) {
635 BUG_ON(!spte);
636 BUG_ON(!(*spte & PT_PRESENT_MASK));
637 rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
638 if (is_writeble_pte(*spte)) {
639 set_shadow_pte(spte, *spte & ~PT_WRITABLE_MASK);
640 write_protected = 1;
641 }
642 spte = rmap_next(kvm, rmapp, spte);
643 }
644 if (write_protected) {
645 pfn_t pfn;
646
647 spte = rmap_next(kvm, rmapp, NULL);
648 pfn = spte_to_pfn(*spte);
649 kvm_set_pfn_dirty(pfn);
650 }
651
652 /* check for huge page mappings */
653 rmapp = gfn_to_rmap(kvm, gfn, 1);
654 spte = rmap_next(kvm, rmapp, NULL);
655 while (spte) {
656 BUG_ON(!spte);
657 BUG_ON(!(*spte & PT_PRESENT_MASK));
658 BUG_ON((*spte & (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK)) != (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK));
659 pgprintk("rmap_write_protect(large): spte %p %llx %lld\n", spte, *spte, gfn);
660 if (is_writeble_pte(*spte)) {
661 rmap_remove(kvm, spte);
662 --kvm->stat.lpages;
663 set_shadow_pte(spte, shadow_trap_nonpresent_pte);
664 spte = NULL;
665 write_protected = 1;
666 }
667 spte = rmap_next(kvm, rmapp, spte);
668 }
669
670 if (write_protected)
671 kvm_flush_remote_tlbs(kvm);
672 }
673
674 static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp)
675 {
676 u64 *spte;
677 int need_tlb_flush = 0;
678
679 while ((spte = rmap_next(kvm, rmapp, NULL))) {
680 BUG_ON(!(*spte & PT_PRESENT_MASK));
681 rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", spte, *spte);
682 rmap_remove(kvm, spte);
683 set_shadow_pte(spte, shadow_trap_nonpresent_pte);
684 need_tlb_flush = 1;
685 }
686 return need_tlb_flush;
687 }
688
689 static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
690 int (*handler)(struct kvm *kvm, unsigned long *rmapp))
691 {
692 int i;
693 int retval = 0;
694
695 /*
696 * If mmap_sem isn't taken, we can look the memslots with only
697 * the mmu_lock by skipping over the slots with userspace_addr == 0.
698 */
699 for (i = 0; i < kvm->nmemslots; i++) {
700 struct kvm_memory_slot *memslot = &kvm->memslots[i];
701 unsigned long start = memslot->userspace_addr;
702 unsigned long end;
703
704 /* mmu_lock protects userspace_addr */
705 if (!start)
706 continue;
707
708 end = start + (memslot->npages << PAGE_SHIFT);
709 if (hva >= start && hva < end) {
710 gfn_t gfn_offset = (hva - start) >> PAGE_SHIFT;
711 retval |= handler(kvm, &memslot->rmap[gfn_offset]);
712 retval |= handler(kvm,
713 &memslot->lpage_info[
714 gfn_offset /
715 KVM_PAGES_PER_HPAGE].rmap_pde);
716 }
717 }
718
719 return retval;
720 }
721
722 int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
723 {
724 return kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
725 }
726
727 static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp)
728 {
729 u64 *spte;
730 int young = 0;
731
732 /* always return old for EPT */
733 if (!shadow_accessed_mask)
734 return 0;
735
736 spte = rmap_next(kvm, rmapp, NULL);
737 while (spte) {
738 int _young;
739 u64 _spte = *spte;
740 BUG_ON(!(_spte & PT_PRESENT_MASK));
741 _young = _spte & PT_ACCESSED_MASK;
742 if (_young) {
743 young = 1;
744 clear_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte);
745 }
746 spte = rmap_next(kvm, rmapp, spte);
747 }
748 return young;
749 }
750
751 int kvm_age_hva(struct kvm *kvm, unsigned long hva)
752 {
753 return kvm_handle_hva(kvm, hva, kvm_age_rmapp);
754 }
755
756 #ifdef MMU_DEBUG
757 static int is_empty_shadow_page(u64 *spt)
758 {
759 u64 *pos;
760 u64 *end;
761
762 for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
763 if (is_shadow_present_pte(*pos)) {
764 printk(KERN_ERR "%s: %p %llx\n", __func__,
765 pos, *pos);
766 return 0;
767 }
768 return 1;
769 }
770 #endif
771
772 static void kvm_mmu_free_page(struct kvm *kvm, struct kvm_mmu_page *sp)
773 {
774 ASSERT(is_empty_shadow_page(sp->spt));
775 list_del(&sp->link);
776 __free_page(virt_to_page(sp->spt));
777 __free_page(virt_to_page(sp->gfns));
778 kfree(sp);
779 ++kvm->arch.n_free_mmu_pages;
780 }
781
782 static unsigned kvm_page_table_hashfn(gfn_t gfn)
783 {
784 return gfn & ((1 << KVM_MMU_HASH_SHIFT) - 1);
785 }
786
787 static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
788 u64 *parent_pte)
789 {
790 struct kvm_mmu_page *sp;
791
792 sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache, sizeof *sp);
793 sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
794 sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
795 set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
796 list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
797 ASSERT(is_empty_shadow_page(sp->spt));
798 bitmap_zero(sp->slot_bitmap, KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS);
799 sp->multimapped = 0;
800 sp->parent_pte = parent_pte;
801 --vcpu->kvm->arch.n_free_mmu_pages;
802 return sp;
803 }
804
805 static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
806 struct kvm_mmu_page *sp, u64 *parent_pte)
807 {
808 struct kvm_pte_chain *pte_chain;
809 struct hlist_node *node;
810 int i;
811
812 if (!parent_pte)
813 return;
814 if (!sp->multimapped) {
815 u64 *old = sp->parent_pte;
816
817 if (!old) {
818 sp->parent_pte = parent_pte;
819 return;
820 }
821 sp->multimapped = 1;
822 pte_chain = mmu_alloc_pte_chain(vcpu);
823 INIT_HLIST_HEAD(&sp->parent_ptes);
824 hlist_add_head(&pte_chain->link, &sp->parent_ptes);
825 pte_chain->parent_ptes[0] = old;
826 }
827 hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link) {
828 if (pte_chain->parent_ptes[NR_PTE_CHAIN_ENTRIES-1])
829 continue;
830 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i)
831 if (!pte_chain->parent_ptes[i]) {
832 pte_chain->parent_ptes[i] = parent_pte;
833 return;
834 }
835 }
836 pte_chain = mmu_alloc_pte_chain(vcpu);
837 BUG_ON(!pte_chain);
838 hlist_add_head(&pte_chain->link, &sp->parent_ptes);
839 pte_chain->parent_ptes[0] = parent_pte;
840 }
841
842 static void mmu_page_remove_parent_pte(struct kvm_mmu_page *sp,
843 u64 *parent_pte)
844 {
845 struct kvm_pte_chain *pte_chain;
846 struct hlist_node *node;
847 int i;
848
849 if (!sp->multimapped) {
850 BUG_ON(sp->parent_pte != parent_pte);
851 sp->parent_pte = NULL;
852 return;
853 }
854 hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
855 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
856 if (!pte_chain->parent_ptes[i])
857 break;
858 if (pte_chain->parent_ptes[i] != parent_pte)
859 continue;
860 while (i + 1 < NR_PTE_CHAIN_ENTRIES
861 && pte_chain->parent_ptes[i + 1]) {
862 pte_chain->parent_ptes[i]
863 = pte_chain->parent_ptes[i + 1];
864 ++i;
865 }
866 pte_chain->parent_ptes[i] = NULL;
867 if (i == 0) {
868 hlist_del(&pte_chain->link);
869 mmu_free_pte_chain(pte_chain);
870 if (hlist_empty(&sp->parent_ptes)) {
871 sp->multimapped = 0;
872 sp->parent_pte = NULL;
873 }
874 }
875 return;
876 }
877 BUG();
878 }
879
880
881 static void mmu_parent_walk(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
882 mmu_parent_walk_fn fn)
883 {
884 struct kvm_pte_chain *pte_chain;
885 struct hlist_node *node;
886 struct kvm_mmu_page *parent_sp;
887 int i;
888
889 if (!sp->multimapped && sp->parent_pte) {
890 parent_sp = page_header(__pa(sp->parent_pte));
891 fn(vcpu, parent_sp);
892 mmu_parent_walk(vcpu, parent_sp, fn);
893 return;
894 }
895 hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
896 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
897 if (!pte_chain->parent_ptes[i])
898 break;
899 parent_sp = page_header(__pa(pte_chain->parent_ptes[i]));
900 fn(vcpu, parent_sp);
901 mmu_parent_walk(vcpu, parent_sp, fn);
902 }
903 }
904
905 static void kvm_mmu_update_unsync_bitmap(u64 *spte)
906 {
907 unsigned int index;
908 struct kvm_mmu_page *sp = page_header(__pa(spte));
909
910 index = spte - sp->spt;
911 __set_bit(index, sp->unsync_child_bitmap);
912 sp->unsync_children = 1;
913 }
914
915 static void kvm_mmu_update_parents_unsync(struct kvm_mmu_page *sp)
916 {
917 struct kvm_pte_chain *pte_chain;
918 struct hlist_node *node;
919 int i;
920
921 if (!sp->parent_pte)
922 return;
923
924 if (!sp->multimapped) {
925 kvm_mmu_update_unsync_bitmap(sp->parent_pte);
926 return;
927 }
928
929 hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
930 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
931 if (!pte_chain->parent_ptes[i])
932 break;
933 kvm_mmu_update_unsync_bitmap(pte_chain->parent_ptes[i]);
934 }
935 }
936
937 static int unsync_walk_fn(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
938 {
939 sp->unsync_children = 1;
940 kvm_mmu_update_parents_unsync(sp);
941 return 1;
942 }
943
944 static void kvm_mmu_mark_parents_unsync(struct kvm_vcpu *vcpu,
945 struct kvm_mmu_page *sp)
946 {
947 mmu_parent_walk(vcpu, sp, unsync_walk_fn);
948 kvm_mmu_update_parents_unsync(sp);
949 }
950
951 static void nonpaging_prefetch_page(struct kvm_vcpu *vcpu,
952 struct kvm_mmu_page *sp)
953 {
954 int i;
955
956 for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
957 sp->spt[i] = shadow_trap_nonpresent_pte;
958 }
959
960 static int nonpaging_sync_page(struct kvm_vcpu *vcpu,
961 struct kvm_mmu_page *sp)
962 {
963 return 1;
964 }
965
966 static void nonpaging_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
967 {
968 }
969
970 #define for_each_unsync_children(bitmap, idx) \
971 for (idx = find_first_bit(bitmap, 512); \
972 idx < 512; \
973 idx = find_next_bit(bitmap, 512, idx+1))
974
975 static int mmu_unsync_walk(struct kvm_mmu_page *sp,
976 struct kvm_unsync_walk *walker)
977 {
978 int i, ret;
979
980 if (!sp->unsync_children)
981 return 0;
982
983 for_each_unsync_children(sp->unsync_child_bitmap, i) {
984 u64 ent = sp->spt[i];
985
986 if (is_shadow_present_pte(ent)) {
987 struct kvm_mmu_page *child;
988 child = page_header(ent & PT64_BASE_ADDR_MASK);
989
990 if (child->unsync_children) {
991 ret = mmu_unsync_walk(child, walker);
992 if (ret)
993 return ret;
994 __clear_bit(i, sp->unsync_child_bitmap);
995 }
996
997 if (child->unsync) {
998 ret = walker->entry(child, walker);
999 __clear_bit(i, sp->unsync_child_bitmap);
1000 if (ret)
1001 return ret;
1002 }
1003 }
1004 }
1005
1006 if (find_first_bit(sp->unsync_child_bitmap, 512) == 512)
1007 sp->unsync_children = 0;
1008
1009 return 0;
1010 }
1011
1012 static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm *kvm, gfn_t gfn)
1013 {
1014 unsigned index;
1015 struct hlist_head *bucket;
1016 struct kvm_mmu_page *sp;
1017 struct hlist_node *node;
1018
1019 pgprintk("%s: looking for gfn %lx\n", __func__, gfn);
1020 index = kvm_page_table_hashfn(gfn);
1021 bucket = &kvm->arch.mmu_page_hash[index];
1022 hlist_for_each_entry(sp, node, bucket, hash_link)
1023 if (sp->gfn == gfn && !sp->role.metaphysical
1024 && !sp->role.invalid) {
1025 pgprintk("%s: found role %x\n",
1026 __func__, sp->role.word);
1027 return sp;
1028 }
1029 return NULL;
1030 }
1031
1032 static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
1033 {
1034 WARN_ON(!sp->unsync);
1035 sp->unsync = 0;
1036 --kvm->stat.mmu_unsync;
1037 }
1038
1039 static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp);
1040
1041 static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
1042 {
1043 if (sp->role.glevels != vcpu->arch.mmu.root_level) {
1044 kvm_mmu_zap_page(vcpu->kvm, sp);
1045 return 1;
1046 }
1047
1048 rmap_write_protect(vcpu->kvm, sp->gfn);
1049 kvm_unlink_unsync_page(vcpu->kvm, sp);
1050 if (vcpu->arch.mmu.sync_page(vcpu, sp)) {
1051 kvm_mmu_zap_page(vcpu->kvm, sp);
1052 return 1;
1053 }
1054
1055 kvm_mmu_flush_tlb(vcpu);
1056 return 0;
1057 }
1058
1059 struct sync_walker {
1060 struct kvm_vcpu *vcpu;
1061 struct kvm_unsync_walk walker;
1062 };
1063
1064 static int mmu_sync_fn(struct kvm_mmu_page *sp, struct kvm_unsync_walk *walk)
1065 {
1066 struct sync_walker *sync_walk = container_of(walk, struct sync_walker,
1067 walker);
1068 struct kvm_vcpu *vcpu = sync_walk->vcpu;
1069
1070 kvm_sync_page(vcpu, sp);
1071 return (need_resched() || spin_needbreak(&vcpu->kvm->mmu_lock));
1072 }
1073
1074 static void mmu_sync_children(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
1075 {
1076 struct sync_walker walker = {
1077 .walker = { .entry = mmu_sync_fn, },
1078 .vcpu = vcpu,
1079 };
1080
1081 while (mmu_unsync_walk(sp, &walker.walker))
1082 cond_resched_lock(&vcpu->kvm->mmu_lock);
1083 }
1084
1085 static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
1086 gfn_t gfn,
1087 gva_t gaddr,
1088 unsigned level,
1089 int metaphysical,
1090 unsigned access,
1091 u64 *parent_pte)
1092 {
1093 union kvm_mmu_page_role role;
1094 unsigned index;
1095 unsigned quadrant;
1096 struct hlist_head *bucket;
1097 struct kvm_mmu_page *sp;
1098 struct hlist_node *node, *tmp;
1099
1100 role.word = 0;
1101 role.glevels = vcpu->arch.mmu.root_level;
1102 role.level = level;
1103 role.metaphysical = metaphysical;
1104 role.access = access;
1105 if (vcpu->arch.mmu.root_level <= PT32_ROOT_LEVEL) {
1106 quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
1107 quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
1108 role.quadrant = quadrant;
1109 }
1110 pgprintk("%s: looking gfn %lx role %x\n", __func__,
1111 gfn, role.word);
1112 index = kvm_page_table_hashfn(gfn);
1113 bucket = &vcpu->kvm->arch.mmu_page_hash[index];
1114 hlist_for_each_entry_safe(sp, node, tmp, bucket, hash_link)
1115 if (sp->gfn == gfn) {
1116 if (sp->unsync)
1117 if (kvm_sync_page(vcpu, sp))
1118 continue;
1119
1120 if (sp->role.word != role.word)
1121 continue;
1122
1123 mmu_page_add_parent_pte(vcpu, sp, parent_pte);
1124 if (sp->unsync_children) {
1125 set_bit(KVM_REQ_MMU_SYNC, &vcpu->requests);
1126 kvm_mmu_mark_parents_unsync(vcpu, sp);
1127 }
1128 pgprintk("%s: found\n", __func__);
1129 return sp;
1130 }
1131 ++vcpu->kvm->stat.mmu_cache_miss;
1132 sp = kvm_mmu_alloc_page(vcpu, parent_pte);
1133 if (!sp)
1134 return sp;
1135 pgprintk("%s: adding gfn %lx role %x\n", __func__, gfn, role.word);
1136 sp->gfn = gfn;
1137 sp->role = role;
1138 hlist_add_head(&sp->hash_link, bucket);
1139 if (!metaphysical) {
1140 rmap_write_protect(vcpu->kvm, gfn);
1141 account_shadowed(vcpu->kvm, gfn);
1142 }
1143 if (shadow_trap_nonpresent_pte != shadow_notrap_nonpresent_pte)
1144 vcpu->arch.mmu.prefetch_page(vcpu, sp);
1145 else
1146 nonpaging_prefetch_page(vcpu, sp);
1147 return sp;
1148 }
1149
1150 static int walk_shadow(struct kvm_shadow_walk *walker,
1151 struct kvm_vcpu *vcpu, u64 addr)
1152 {
1153 hpa_t shadow_addr;
1154 int level;
1155 int r;
1156 u64 *sptep;
1157 unsigned index;
1158
1159 shadow_addr = vcpu->arch.mmu.root_hpa;
1160 level = vcpu->arch.mmu.shadow_root_level;
1161 if (level == PT32E_ROOT_LEVEL) {
1162 shadow_addr = vcpu->arch.mmu.pae_root[(addr >> 30) & 3];
1163 shadow_addr &= PT64_BASE_ADDR_MASK;
1164 --level;
1165 }
1166
1167 while (level >= PT_PAGE_TABLE_LEVEL) {
1168 index = SHADOW_PT_INDEX(addr, level);
1169 sptep = ((u64 *)__va(shadow_addr)) + index;
1170 r = walker->entry(walker, vcpu, addr, sptep, level);
1171 if (r)
1172 return r;
1173 shadow_addr = *sptep & PT64_BASE_ADDR_MASK;
1174 --level;
1175 }
1176 return 0;
1177 }
1178
1179 static void kvm_mmu_page_unlink_children(struct kvm *kvm,
1180 struct kvm_mmu_page *sp)
1181 {
1182 unsigned i;
1183 u64 *pt;
1184 u64 ent;
1185
1186 pt = sp->spt;
1187
1188 if (sp->role.level == PT_PAGE_TABLE_LEVEL) {
1189 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
1190 if (is_shadow_present_pte(pt[i]))
1191 rmap_remove(kvm, &pt[i]);
1192 pt[i] = shadow_trap_nonpresent_pte;
1193 }
1194 return;
1195 }
1196
1197 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
1198 ent = pt[i];
1199
1200 if (is_shadow_present_pte(ent)) {
1201 if (!is_large_pte(ent)) {
1202 ent &= PT64_BASE_ADDR_MASK;
1203 mmu_page_remove_parent_pte(page_header(ent),
1204 &pt[i]);
1205 } else {
1206 --kvm->stat.lpages;
1207 rmap_remove(kvm, &pt[i]);
1208 }
1209 }
1210 pt[i] = shadow_trap_nonpresent_pte;
1211 }
1212 }
1213
1214 static void kvm_mmu_put_page(struct kvm_mmu_page *sp, u64 *parent_pte)
1215 {
1216 mmu_page_remove_parent_pte(sp, parent_pte);
1217 }
1218
1219 static void kvm_mmu_reset_last_pte_updated(struct kvm *kvm)
1220 {
1221 int i;
1222
1223 for (i = 0; i < KVM_MAX_VCPUS; ++i)
1224 if (kvm->vcpus[i])
1225 kvm->vcpus[i]->arch.last_pte_updated = NULL;
1226 }
1227
1228 static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp)
1229 {
1230 u64 *parent_pte;
1231
1232 while (sp->multimapped || sp->parent_pte) {
1233 if (!sp->multimapped)
1234 parent_pte = sp->parent_pte;
1235 else {
1236 struct kvm_pte_chain *chain;
1237
1238 chain = container_of(sp->parent_ptes.first,
1239 struct kvm_pte_chain, link);
1240 parent_pte = chain->parent_ptes[0];
1241 }
1242 BUG_ON(!parent_pte);
1243 kvm_mmu_put_page(sp, parent_pte);
1244 set_shadow_pte(parent_pte, shadow_trap_nonpresent_pte);
1245 }
1246 }
1247
1248 struct zap_walker {
1249 struct kvm_unsync_walk walker;
1250 struct kvm *kvm;
1251 int zapped;
1252 };
1253
1254 static int mmu_zap_fn(struct kvm_mmu_page *sp, struct kvm_unsync_walk *walk)
1255 {
1256 struct zap_walker *zap_walk = container_of(walk, struct zap_walker,
1257 walker);
1258 kvm_mmu_zap_page(zap_walk->kvm, sp);
1259 zap_walk->zapped = 1;
1260 return 0;
1261 }
1262
1263 static int mmu_zap_unsync_children(struct kvm *kvm, struct kvm_mmu_page *sp)
1264 {
1265 struct zap_walker walker = {
1266 .walker = { .entry = mmu_zap_fn, },
1267 .kvm = kvm,
1268 .zapped = 0,
1269 };
1270
1271 if (sp->role.level == PT_PAGE_TABLE_LEVEL)
1272 return 0;
1273 mmu_unsync_walk(sp, &walker.walker);
1274 return walker.zapped;
1275 }
1276
1277 static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp)
1278 {
1279 int ret;
1280 ++kvm->stat.mmu_shadow_zapped;
1281 ret = mmu_zap_unsync_children(kvm, sp);
1282 kvm_mmu_page_unlink_children(kvm, sp);
1283 kvm_mmu_unlink_parents(kvm, sp);
1284 kvm_flush_remote_tlbs(kvm);
1285 if (!sp->role.invalid && !sp->role.metaphysical)
1286 unaccount_shadowed(kvm, sp->gfn);
1287 if (sp->unsync)
1288 kvm_unlink_unsync_page(kvm, sp);
1289 if (!sp->root_count) {
1290 hlist_del(&sp->hash_link);
1291 kvm_mmu_free_page(kvm, sp);
1292 } else {
1293 sp->role.invalid = 1;
1294 list_move(&sp->link, &kvm->arch.active_mmu_pages);
1295 kvm_reload_remote_mmus(kvm);
1296 }
1297 kvm_mmu_reset_last_pte_updated(kvm);
1298 return ret;
1299 }
1300
1301 /*
1302 * Changing the number of mmu pages allocated to the vm
1303 * Note: if kvm_nr_mmu_pages is too small, you will get dead lock
1304 */
1305 void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages)
1306 {
1307 /*
1308 * If we set the number of mmu pages to be smaller be than the
1309 * number of actived pages , we must to free some mmu pages before we
1310 * change the value
1311 */
1312
1313 if ((kvm->arch.n_alloc_mmu_pages - kvm->arch.n_free_mmu_pages) >
1314 kvm_nr_mmu_pages) {
1315 int n_used_mmu_pages = kvm->arch.n_alloc_mmu_pages
1316 - kvm->arch.n_free_mmu_pages;
1317
1318 while (n_used_mmu_pages > kvm_nr_mmu_pages) {
1319 struct kvm_mmu_page *page;
1320
1321 page = container_of(kvm->arch.active_mmu_pages.prev,
1322 struct kvm_mmu_page, link);
1323 kvm_mmu_zap_page(kvm, page);
1324 n_used_mmu_pages--;
1325 }
1326 kvm->arch.n_free_mmu_pages = 0;
1327 }
1328 else
1329 kvm->arch.n_free_mmu_pages += kvm_nr_mmu_pages
1330 - kvm->arch.n_alloc_mmu_pages;
1331
1332 kvm->arch.n_alloc_mmu_pages = kvm_nr_mmu_pages;
1333 }
1334
1335 static int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
1336 {
1337 unsigned index;
1338 struct hlist_head *bucket;
1339 struct kvm_mmu_page *sp;
1340 struct hlist_node *node, *n;
1341 int r;
1342
1343 pgprintk("%s: looking for gfn %lx\n", __func__, gfn);
1344 r = 0;
1345 index = kvm_page_table_hashfn(gfn);
1346 bucket = &kvm->arch.mmu_page_hash[index];
1347 hlist_for_each_entry_safe(sp, node, n, bucket, hash_link)
1348 if (sp->gfn == gfn && !sp->role.metaphysical) {
1349 pgprintk("%s: gfn %lx role %x\n", __func__, gfn,
1350 sp->role.word);
1351 r = 1;
1352 if (kvm_mmu_zap_page(kvm, sp))
1353 n = bucket->first;
1354 }
1355 return r;
1356 }
1357
1358 static void mmu_unshadow(struct kvm *kvm, gfn_t gfn)
1359 {
1360 struct kvm_mmu_page *sp;
1361
1362 while ((sp = kvm_mmu_lookup_page(kvm, gfn)) != NULL) {
1363 pgprintk("%s: zap %lx %x\n", __func__, gfn, sp->role.word);
1364 kvm_mmu_zap_page(kvm, sp);
1365 }
1366 }
1367
1368 static void page_header_update_slot(struct kvm *kvm, void *pte, gfn_t gfn)
1369 {
1370 int slot = memslot_id(kvm, gfn_to_memslot(kvm, gfn));
1371 struct kvm_mmu_page *sp = page_header(__pa(pte));
1372
1373 __set_bit(slot, sp->slot_bitmap);
1374 }
1375
1376 static void mmu_convert_notrap(struct kvm_mmu_page *sp)
1377 {
1378 int i;
1379 u64 *pt = sp->spt;
1380
1381 if (shadow_trap_nonpresent_pte == shadow_notrap_nonpresent_pte)
1382 return;
1383
1384 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
1385 if (pt[i] == shadow_notrap_nonpresent_pte)
1386 set_shadow_pte(&pt[i], shadow_trap_nonpresent_pte);
1387 }
1388 }
1389
1390 struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva)
1391 {
1392 struct page *page;
1393
1394 gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva);
1395
1396 if (gpa == UNMAPPED_GVA)
1397 return NULL;
1398
1399 page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);
1400
1401 return page;
1402 }
1403
1404 /*
1405 * The function is based on mtrr_type_lookup() in
1406 * arch/x86/kernel/cpu/mtrr/generic.c
1407 */
1408 static int get_mtrr_type(struct mtrr_state_type *mtrr_state,
1409 u64 start, u64 end)
1410 {
1411 int i;
1412 u64 base, mask;
1413 u8 prev_match, curr_match;
1414 int num_var_ranges = KVM_NR_VAR_MTRR;
1415
1416 if (!mtrr_state->enabled)
1417 return 0xFF;
1418
1419 /* Make end inclusive end, instead of exclusive */
1420 end--;
1421
1422 /* Look in fixed ranges. Just return the type as per start */
1423 if (mtrr_state->have_fixed && (start < 0x100000)) {
1424 int idx;
1425
1426 if (start < 0x80000) {
1427 idx = 0;
1428 idx += (start >> 16);
1429 return mtrr_state->fixed_ranges[idx];
1430 } else if (start < 0xC0000) {
1431 idx = 1 * 8;
1432 idx += ((start - 0x80000) >> 14);
1433 return mtrr_state->fixed_ranges[idx];
1434 } else if (start < 0x1000000) {
1435 idx = 3 * 8;
1436 idx += ((start - 0xC0000) >> 12);
1437 return mtrr_state->fixed_ranges[idx];
1438 }
1439 }
1440
1441 /*
1442 * Look in variable ranges
1443 * Look of multiple ranges matching this address and pick type
1444 * as per MTRR precedence
1445 */
1446 if (!(mtrr_state->enabled & 2))
1447 return mtrr_state->def_type;
1448
1449 prev_match = 0xFF;
1450 for (i = 0; i < num_var_ranges; ++i) {
1451 unsigned short start_state, end_state;
1452
1453 if (!(mtrr_state->var_ranges[i].mask_lo & (1 << 11)))
1454 continue;
1455
1456 base = (((u64)mtrr_state->var_ranges[i].base_hi) << 32) +
1457 (mtrr_state->var_ranges[i].base_lo & PAGE_MASK);
1458 mask = (((u64)mtrr_state->var_ranges[i].mask_hi) << 32) +
1459 (mtrr_state->var_ranges[i].mask_lo & PAGE_MASK);
1460
1461 start_state = ((start & mask) == (base & mask));
1462 end_state = ((end & mask) == (base & mask));
1463 if (start_state != end_state)
1464 return 0xFE;
1465
1466 if ((start & mask) != (base & mask))
1467 continue;
1468
1469 curr_match = mtrr_state->var_ranges[i].base_lo & 0xff;
1470 if (prev_match == 0xFF) {
1471 prev_match = curr_match;
1472 continue;
1473 }
1474
1475 if (prev_match == MTRR_TYPE_UNCACHABLE ||
1476 curr_match == MTRR_TYPE_UNCACHABLE)
1477 return MTRR_TYPE_UNCACHABLE;
1478
1479 if ((prev_match == MTRR_TYPE_WRBACK &&
1480 curr_match == MTRR_TYPE_WRTHROUGH) ||
1481 (prev_match == MTRR_TYPE_WRTHROUGH &&
1482 curr_match == MTRR_TYPE_WRBACK)) {
1483 prev_match = MTRR_TYPE_WRTHROUGH;
1484 curr_match = MTRR_TYPE_WRTHROUGH;
1485 }
1486
1487 if (prev_match != curr_match)
1488 return MTRR_TYPE_UNCACHABLE;
1489 }
1490
1491 if (prev_match != 0xFF)
1492 return prev_match;
1493
1494 return mtrr_state->def_type;
1495 }
1496
1497 static u8 get_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)
1498 {
1499 u8 mtrr;
1500
1501 mtrr = get_mtrr_type(&vcpu->arch.mtrr_state, gfn << PAGE_SHIFT,
1502 (gfn << PAGE_SHIFT) + PAGE_SIZE);
1503 if (mtrr == 0xfe || mtrr == 0xff)
1504 mtrr = MTRR_TYPE_WRBACK;
1505 return mtrr;
1506 }
1507
1508 static int kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
1509 {
1510 unsigned index;
1511 struct hlist_head *bucket;
1512 struct kvm_mmu_page *s;
1513 struct hlist_node *node, *n;
1514
1515 index = kvm_page_table_hashfn(sp->gfn);
1516 bucket = &vcpu->kvm->arch.mmu_page_hash[index];
1517 /* don't unsync if pagetable is shadowed with multiple roles */
1518 hlist_for_each_entry_safe(s, node, n, bucket, hash_link) {
1519 if (s->gfn != sp->gfn || s->role.metaphysical)
1520 continue;
1521 if (s->role.word != sp->role.word)
1522 return 1;
1523 }
1524 kvm_mmu_mark_parents_unsync(vcpu, sp);
1525 ++vcpu->kvm->stat.mmu_unsync;
1526 sp->unsync = 1;
1527 mmu_convert_notrap(sp);
1528 return 0;
1529 }
1530
1531 static int mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn,
1532 bool can_unsync)
1533 {
1534 struct kvm_mmu_page *shadow;
1535
1536 shadow = kvm_mmu_lookup_page(vcpu->kvm, gfn);
1537 if (shadow) {
1538 if (shadow->role.level != PT_PAGE_TABLE_LEVEL)
1539 return 1;
1540 if (shadow->unsync)
1541 return 0;
1542 if (can_unsync && oos_shadow)
1543 return kvm_unsync_page(vcpu, shadow);
1544 return 1;
1545 }
1546 return 0;
1547 }
1548
1549 static int set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
1550 unsigned pte_access, int user_fault,
1551 int write_fault, int dirty, int largepage,
1552 gfn_t gfn, pfn_t pfn, bool speculative,
1553 bool can_unsync)
1554 {
1555 u64 spte;
1556 int ret = 0;
1557 u64 mt_mask = shadow_mt_mask;
1558
1559 /*
1560 * We don't set the accessed bit, since we sometimes want to see
1561 * whether the guest actually used the pte (in order to detect
1562 * demand paging).
1563 */
1564 spte = shadow_base_present_pte | shadow_dirty_mask;
1565 if (!speculative)
1566 spte |= shadow_accessed_mask;
1567 if (!dirty)
1568 pte_access &= ~ACC_WRITE_MASK;
1569 if (pte_access & ACC_EXEC_MASK)
1570 spte |= shadow_x_mask;
1571 else
1572 spte |= shadow_nx_mask;
1573 if (pte_access & ACC_USER_MASK)
1574 spte |= shadow_user_mask;
1575 if (largepage)
1576 spte |= PT_PAGE_SIZE_MASK;
1577 if (mt_mask) {
1578 mt_mask = get_memory_type(vcpu, gfn) <<
1579 kvm_x86_ops->get_mt_mask_shift();
1580 spte |= mt_mask;
1581 }
1582
1583 spte |= (u64)pfn << PAGE_SHIFT;
1584
1585 if ((pte_access & ACC_WRITE_MASK)
1586 || (write_fault && !is_write_protection(vcpu) && !user_fault)) {
1587
1588 if (largepage && has_wrprotected_page(vcpu->kvm, gfn)) {
1589 ret = 1;
1590 spte = shadow_trap_nonpresent_pte;
1591 goto set_pte;
1592 }
1593
1594 spte |= PT_WRITABLE_MASK;
1595
1596 /*
1597 * Optimization: for pte sync, if spte was writable the hash
1598 * lookup is unnecessary (and expensive). Write protection
1599 * is responsibility of mmu_get_page / kvm_sync_page.
1600 * Same reasoning can be applied to dirty page accounting.
1601 */
1602 if (!can_unsync && is_writeble_pte(*shadow_pte))
1603 goto set_pte;
1604
1605 if (mmu_need_write_protect(vcpu, gfn, can_unsync)) {
1606 pgprintk("%s: found shadow page for %lx, marking ro\n",
1607 __func__, gfn);
1608 ret = 1;
1609 pte_access &= ~ACC_WRITE_MASK;
1610 if (is_writeble_pte(spte))
1611 spte &= ~PT_WRITABLE_MASK;
1612 }
1613 }
1614
1615 if (pte_access & ACC_WRITE_MASK)
1616 mark_page_dirty(vcpu->kvm, gfn);
1617
1618 set_pte:
1619 set_shadow_pte(shadow_pte, spte);
1620 return ret;
1621 }
1622
1623 static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
1624 unsigned pt_access, unsigned pte_access,
1625 int user_fault, int write_fault, int dirty,
1626 int *ptwrite, int largepage, gfn_t gfn,
1627 pfn_t pfn, bool speculative)
1628 {
1629 int was_rmapped = 0;
1630 int was_writeble = is_writeble_pte(*shadow_pte);
1631
1632 pgprintk("%s: spte %llx access %x write_fault %d"
1633 " user_fault %d gfn %lx\n",
1634 __func__, *shadow_pte, pt_access,
1635 write_fault, user_fault, gfn);
1636
1637 if (is_rmap_pte(*shadow_pte)) {
1638 /*
1639 * If we overwrite a PTE page pointer with a 2MB PMD, unlink
1640 * the parent of the now unreachable PTE.
1641 */
1642 if (largepage && !is_large_pte(*shadow_pte)) {
1643 struct kvm_mmu_page *child;
1644 u64 pte = *shadow_pte;
1645
1646 child = page_header(pte & PT64_BASE_ADDR_MASK);
1647 mmu_page_remove_parent_pte(child, shadow_pte);
1648 } else if (pfn != spte_to_pfn(*shadow_pte)) {
1649 pgprintk("hfn old %lx new %lx\n",
1650 spte_to_pfn(*shadow_pte), pfn);
1651 rmap_remove(vcpu->kvm, shadow_pte);
1652 } else {
1653 if (largepage)
1654 was_rmapped = is_large_pte(*shadow_pte);
1655 else
1656 was_rmapped = 1;
1657 }
1658 }
1659 if (set_spte(vcpu, shadow_pte, pte_access, user_fault, write_fault,
1660 dirty, largepage, gfn, pfn, speculative, true)) {
1661 if (write_fault)
1662 *ptwrite = 1;
1663 kvm_x86_ops->tlb_flush(vcpu);
1664 }
1665
1666 pgprintk("%s: setting spte %llx\n", __func__, *shadow_pte);
1667 pgprintk("instantiating %s PTE (%s) at %ld (%llx) addr %p\n",
1668 is_large_pte(*shadow_pte)? "2MB" : "4kB",
1669 is_present_pte(*shadow_pte)?"RW":"R", gfn,
1670 *shadow_pte, shadow_pte);
1671 if (!was_rmapped && is_large_pte(*shadow_pte))
1672 ++vcpu->kvm->stat.lpages;
1673
1674 page_header_update_slot(vcpu->kvm, shadow_pte, gfn);
1675 if (!was_rmapped) {
1676 rmap_add(vcpu, shadow_pte, gfn, largepage);
1677 if (!is_rmap_pte(*shadow_pte))
1678 kvm_release_pfn_clean(pfn);
1679 } else {
1680 if (was_writeble)
1681 kvm_release_pfn_dirty(pfn);
1682 else
1683 kvm_release_pfn_clean(pfn);
1684 }
1685 if (speculative) {
1686 vcpu->arch.last_pte_updated = shadow_pte;
1687 vcpu->arch.last_pte_gfn = gfn;
1688 }
1689 }
1690
1691 static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
1692 {
1693 }
1694
1695 struct direct_shadow_walk {
1696 struct kvm_shadow_walk walker;
1697 pfn_t pfn;
1698 int write;
1699 int largepage;
1700 int pt_write;
1701 };
1702
1703 static int direct_map_entry(struct kvm_shadow_walk *_walk,
1704 struct kvm_vcpu *vcpu,
1705 u64 addr, u64 *sptep, int level)
1706 {
1707 struct direct_shadow_walk *walk =
1708 container_of(_walk, struct direct_shadow_walk, walker);
1709 struct kvm_mmu_page *sp;
1710 gfn_t pseudo_gfn;
1711 gfn_t gfn = addr >> PAGE_SHIFT;
1712
1713 if (level == PT_PAGE_TABLE_LEVEL
1714 || (walk->largepage && level == PT_DIRECTORY_LEVEL)) {
1715 mmu_set_spte(vcpu, sptep, ACC_ALL, ACC_ALL,
1716 0, walk->write, 1, &walk->pt_write,
1717 walk->largepage, gfn, walk->pfn, false);
1718 ++vcpu->stat.pf_fixed;
1719 return 1;
1720 }
1721
1722 if (*sptep == shadow_trap_nonpresent_pte) {
1723 pseudo_gfn = (addr & PT64_DIR_BASE_ADDR_MASK) >> PAGE_SHIFT;
1724 sp = kvm_mmu_get_page(vcpu, pseudo_gfn, (gva_t)addr, level - 1,
1725 1, ACC_ALL, sptep);
1726 if (!sp) {
1727 pgprintk("nonpaging_map: ENOMEM\n");
1728 kvm_release_pfn_clean(walk->pfn);
1729 return -ENOMEM;
1730 }
1731
1732 set_shadow_pte(sptep,
1733 __pa(sp->spt)
1734 | PT_PRESENT_MASK | PT_WRITABLE_MASK
1735 | shadow_user_mask | shadow_x_mask);
1736 }
1737 return 0;
1738 }
1739
1740 static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
1741 int largepage, gfn_t gfn, pfn_t pfn)
1742 {
1743 int r;
1744 struct direct_shadow_walk walker = {
1745 .walker = { .entry = direct_map_entry, },
1746 .pfn = pfn,
1747 .largepage = largepage,
1748 .write = write,
1749 .pt_write = 0,
1750 };
1751
1752 r = walk_shadow(&walker.walker, vcpu, gfn << PAGE_SHIFT);
1753 if (r < 0)
1754 return r;
1755 return walker.pt_write;
1756 }
1757
1758 static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
1759 {
1760 int r;
1761 int largepage = 0;
1762 pfn_t pfn;
1763 unsigned long mmu_seq;
1764
1765 if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
1766 gfn &= ~(KVM_PAGES_PER_HPAGE-1);
1767 largepage = 1;
1768 }
1769
1770 mmu_seq = vcpu->kvm->mmu_notifier_seq;
1771 smp_rmb();
1772 pfn = gfn_to_pfn(vcpu->kvm, gfn);
1773
1774 /* mmio */
1775 if (is_error_pfn(pfn)) {
1776 kvm_release_pfn_clean(pfn);
1777 return 1;
1778 }
1779
1780 spin_lock(&vcpu->kvm->mmu_lock);
1781 if (mmu_notifier_retry(vcpu, mmu_seq))
1782 goto out_unlock;
1783 kvm_mmu_free_some_pages(vcpu);
1784 r = __direct_map(vcpu, v, write, largepage, gfn, pfn);
1785 spin_unlock(&vcpu->kvm->mmu_lock);
1786
1787
1788 return r;
1789
1790 out_unlock:
1791 spin_unlock(&vcpu->kvm->mmu_lock);
1792 kvm_release_pfn_clean(pfn);
1793 return 0;
1794 }
1795
1796
1797 static void mmu_free_roots(struct kvm_vcpu *vcpu)
1798 {
1799 int i;
1800 struct kvm_mmu_page *sp;
1801
1802 if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
1803 return;
1804 spin_lock(&vcpu->kvm->mmu_lock);
1805 if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
1806 hpa_t root = vcpu->arch.mmu.root_hpa;
1807
1808 sp = page_header(root);
1809 --sp->root_count;
1810 if (!sp->root_count && sp->role.invalid)
1811 kvm_mmu_zap_page(vcpu->kvm, sp);
1812 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
1813 spin_unlock(&vcpu->kvm->mmu_lock);
1814 return;
1815 }
1816 for (i = 0; i < 4; ++i) {
1817 hpa_t root = vcpu->arch.mmu.pae_root[i];
1818
1819 if (root) {
1820 root &= PT64_BASE_ADDR_MASK;
1821 sp = page_header(root);
1822 --sp->root_count;
1823 if (!sp->root_count && sp->role.invalid)
1824 kvm_mmu_zap_page(vcpu->kvm, sp);
1825 }
1826 vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
1827 }
1828 spin_unlock(&vcpu->kvm->mmu_lock);
1829 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
1830 }
1831
1832 static void mmu_alloc_roots(struct kvm_vcpu *vcpu)
1833 {
1834 int i;
1835 gfn_t root_gfn;
1836 struct kvm_mmu_page *sp;
1837 int metaphysical = 0;
1838
1839 root_gfn = vcpu->arch.cr3 >> PAGE_SHIFT;
1840
1841 if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
1842 hpa_t root = vcpu->arch.mmu.root_hpa;
1843
1844 ASSERT(!VALID_PAGE(root));
1845 if (tdp_enabled)
1846 metaphysical = 1;
1847 sp = kvm_mmu_get_page(vcpu, root_gfn, 0,
1848 PT64_ROOT_LEVEL, metaphysical,
1849 ACC_ALL, NULL);
1850 root = __pa(sp->spt);
1851 ++sp->root_count;
1852 vcpu->arch.mmu.root_hpa = root;
1853 return;
1854 }
1855 metaphysical = !is_paging(vcpu);
1856 if (tdp_enabled)
1857 metaphysical = 1;
1858 for (i = 0; i < 4; ++i) {
1859 hpa_t root = vcpu->arch.mmu.pae_root[i];
1860
1861 ASSERT(!VALID_PAGE(root));
1862 if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
1863 if (!is_present_pte(vcpu->arch.pdptrs[i])) {
1864 vcpu->arch.mmu.pae_root[i] = 0;
1865 continue;
1866 }
1867 root_gfn = vcpu->arch.pdptrs[i] >> PAGE_SHIFT;
1868 } else if (vcpu->arch.mmu.root_level == 0)
1869 root_gfn = 0;
1870 sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
1871 PT32_ROOT_LEVEL, metaphysical,
1872 ACC_ALL, NULL);
1873 root = __pa(sp->spt);
1874 ++sp->root_count;
1875 vcpu->arch.mmu.pae_root[i] = root | PT_PRESENT_MASK;
1876 }
1877 vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
1878 }
1879
1880 static void mmu_sync_roots(struct kvm_vcpu *vcpu)
1881 {
1882 int i;
1883 struct kvm_mmu_page *sp;
1884
1885 if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
1886 return;
1887 if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
1888 hpa_t root = vcpu->arch.mmu.root_hpa;
1889 sp = page_header(root);
1890 mmu_sync_children(vcpu, sp);
1891 return;
1892 }
1893 for (i = 0; i < 4; ++i) {
1894 hpa_t root = vcpu->arch.mmu.pae_root[i];
1895
1896 if (root) {
1897 root &= PT64_BASE_ADDR_MASK;
1898 sp = page_header(root);
1899 mmu_sync_children(vcpu, sp);
1900 }
1901 }
1902 }
1903
1904 void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
1905 {
1906 spin_lock(&vcpu->kvm->mmu_lock);
1907 mmu_sync_roots(vcpu);
1908 spin_unlock(&vcpu->kvm->mmu_lock);
1909 }
1910
1911 static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr)
1912 {
1913 return vaddr;
1914 }
1915
1916 static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
1917 u32 error_code)
1918 {
1919 gfn_t gfn;
1920 int r;
1921
1922 pgprintk("%s: gva %lx error %x\n", __func__, gva, error_code);
1923 r = mmu_topup_memory_caches(vcpu);
1924 if (r)
1925 return r;
1926
1927 ASSERT(vcpu);
1928 ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
1929
1930 gfn = gva >> PAGE_SHIFT;
1931
1932 return nonpaging_map(vcpu, gva & PAGE_MASK,
1933 error_code & PFERR_WRITE_MASK, gfn);
1934 }
1935
1936 static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
1937 u32 error_code)
1938 {
1939 pfn_t pfn;
1940 int r;
1941 int largepage = 0;
1942 gfn_t gfn = gpa >> PAGE_SHIFT;
1943 unsigned long mmu_seq;
1944
1945 ASSERT(vcpu);
1946 ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
1947
1948 r = mmu_topup_memory_caches(vcpu);
1949 if (r)
1950 return r;
1951
1952 if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
1953 gfn &= ~(KVM_PAGES_PER_HPAGE-1);
1954 largepage = 1;
1955 }
1956 mmu_seq = vcpu->kvm->mmu_notifier_seq;
1957 smp_rmb();
1958 pfn = gfn_to_pfn(vcpu->kvm, gfn);
1959 if (is_error_pfn(pfn)) {
1960 kvm_release_pfn_clean(pfn);
1961 return 1;
1962 }
1963 spin_lock(&vcpu->kvm->mmu_lock);
1964 if (mmu_notifier_retry(vcpu, mmu_seq))
1965 goto out_unlock;
1966 kvm_mmu_free_some_pages(vcpu);
1967 r = __direct_map(vcpu, gpa, error_code & PFERR_WRITE_MASK,
1968 largepage, gfn, pfn);
1969 spin_unlock(&vcpu->kvm->mmu_lock);
1970
1971 return r;
1972
1973 out_unlock:
1974 spin_unlock(&vcpu->kvm->mmu_lock);
1975 kvm_release_pfn_clean(pfn);
1976 return 0;
1977 }
1978
1979 static void nonpaging_free(struct kvm_vcpu *vcpu)
1980 {
1981 mmu_free_roots(vcpu);
1982 }
1983
1984 static int nonpaging_init_context(struct kvm_vcpu *vcpu)
1985 {
1986 struct kvm_mmu *context = &vcpu->arch.mmu;
1987
1988 context->new_cr3 = nonpaging_new_cr3;
1989 context->page_fault = nonpaging_page_fault;
1990 context->gva_to_gpa = nonpaging_gva_to_gpa;
1991 context->free = nonpaging_free;
1992 context->prefetch_page = nonpaging_prefetch_page;
1993 context->sync_page = nonpaging_sync_page;
1994 context->invlpg = nonpaging_invlpg;
1995 context->root_level = 0;
1996 context->shadow_root_level = PT32E_ROOT_LEVEL;
1997 context->root_hpa = INVALID_PAGE;
1998 return 0;
1999 }
2000
2001 void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
2002 {
2003 ++vcpu->stat.tlb_flush;
2004 kvm_x86_ops->tlb_flush(vcpu);
2005 }
2006
2007 static void paging_new_cr3(struct kvm_vcpu *vcpu)
2008 {
2009 pgprintk("%s: cr3 %lx\n", __func__, vcpu->arch.cr3);
2010 mmu_free_roots(vcpu);
2011 }
2012
2013 static void inject_page_fault(struct kvm_vcpu *vcpu,
2014 u64 addr,
2015 u32 err_code)
2016 {
2017 kvm_inject_page_fault(vcpu, addr, err_code);
2018 }
2019
2020 static void paging_free(struct kvm_vcpu *vcpu)
2021 {
2022 nonpaging_free(vcpu);
2023 }
2024
2025 #define PTTYPE 64
2026 #include "paging_tmpl.h"
2027 #undef PTTYPE
2028
2029 #define PTTYPE 32
2030 #include "paging_tmpl.h"
2031 #undef PTTYPE
2032
2033 static int paging64_init_context_common(struct kvm_vcpu *vcpu, int level)
2034 {
2035 struct kvm_mmu *context = &vcpu->arch.mmu;
2036
2037 ASSERT(is_pae(vcpu));
2038 context->new_cr3 = paging_new_cr3;
2039 context->page_fault = paging64_page_fault;
2040 context->gva_to_gpa = paging64_gva_to_gpa;
2041 context->prefetch_page = paging64_prefetch_page;
2042 context->sync_page = paging64_sync_page;
2043 context->invlpg = paging64_invlpg;
2044 context->free = paging_free;
2045 context->root_level = level;
2046 context->shadow_root_level = level;
2047 context->root_hpa = INVALID_PAGE;
2048 return 0;
2049 }
2050
2051 static int paging64_init_context(struct kvm_vcpu *vcpu)
2052 {
2053 return paging64_init_context_common(vcpu, PT64_ROOT_LEVEL);
2054 }
2055
2056 static int paging32_init_context(struct kvm_vcpu *vcpu)
2057 {
2058 struct kvm_mmu *context = &vcpu->arch.mmu;
2059
2060 context->new_cr3 = paging_new_cr3;
2061 context->page_fault = paging32_page_fault;
2062 context->gva_to_gpa = paging32_gva_to_gpa;
2063 context->free = paging_free;
2064 context->prefetch_page = paging32_prefetch_page;
2065 context->sync_page = paging32_sync_page;
2066 context->invlpg = paging32_invlpg;
2067 context->root_level = PT32_ROOT_LEVEL;
2068 context->shadow_root_level = PT32E_ROOT_LEVEL;
2069 context->root_hpa = INVALID_PAGE;
2070 return 0;
2071 }
2072
2073 static int paging32E_init_context(struct kvm_vcpu *vcpu)
2074 {
2075 return paging64_init_context_common(vcpu, PT32E_ROOT_LEVEL);
2076 }
2077
2078 static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
2079 {
2080 struct kvm_mmu *context = &vcpu->arch.mmu;
2081
2082 context->new_cr3 = nonpaging_new_cr3;
2083 context->page_fault = tdp_page_fault;
2084 context->free = nonpaging_free;
2085 context->prefetch_page = nonpaging_prefetch_page;
2086 context->sync_page = nonpaging_sync_page;
2087 context->invlpg = nonpaging_invlpg;
2088 context->shadow_root_level = kvm_x86_ops->get_tdp_level();
2089 context->root_hpa = INVALID_PAGE;
2090
2091 if (!is_paging(vcpu)) {
2092 context->gva_to_gpa = nonpaging_gva_to_gpa;
2093 context->root_level = 0;
2094 } else if (is_long_mode(vcpu)) {
2095 context->gva_to_gpa = paging64_gva_to_gpa;
2096 context->root_level = PT64_ROOT_LEVEL;
2097 } else if (is_pae(vcpu)) {
2098 context->gva_to_gpa = paging64_gva_to_gpa;
2099 context->root_level = PT32E_ROOT_LEVEL;
2100 } else {
2101 context->gva_to_gpa = paging32_gva_to_gpa;
2102 context->root_level = PT32_ROOT_LEVEL;
2103 }
2104
2105 return 0;
2106 }
2107
2108 static int init_kvm_softmmu(struct kvm_vcpu *vcpu)
2109 {
2110 ASSERT(vcpu);
2111 ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
2112
2113 if (!is_paging(vcpu))
2114 return nonpaging_init_context(vcpu);
2115 else if (is_long_mode(vcpu))
2116 return paging64_init_context(vcpu);
2117 else if (is_pae(vcpu))
2118 return paging32E_init_context(vcpu);
2119 else
2120 return paging32_init_context(vcpu);
2121 }
2122
2123 static int init_kvm_mmu(struct kvm_vcpu *vcpu)
2124 {
2125 vcpu->arch.update_pte.pfn = bad_pfn;
2126
2127 if (tdp_enabled)
2128 return init_kvm_tdp_mmu(vcpu);
2129 else
2130 return init_kvm_softmmu(vcpu);
2131 }
2132
2133 static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
2134 {
2135 ASSERT(vcpu);
2136 if (VALID_PAGE(vcpu->arch.mmu.root_hpa)) {
2137 vcpu->arch.mmu.free(vcpu);
2138 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
2139 }
2140 }
2141
2142 int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
2143 {
2144 destroy_kvm_mmu(vcpu);
2145 return init_kvm_mmu(vcpu);
2146 }
2147 EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
2148
2149 int kvm_mmu_load(struct kvm_vcpu *vcpu)
2150 {
2151 int r;
2152
2153 r = mmu_topup_memory_caches(vcpu);
2154 if (r)
2155 goto out;
2156 spin_lock(&vcpu->kvm->mmu_lock);
2157 kvm_mmu_free_some_pages(vcpu);
2158 mmu_alloc_roots(vcpu);
2159 mmu_sync_roots(vcpu);
2160 spin_unlock(&vcpu->kvm->mmu_lock);
2161 kvm_x86_ops->set_cr3(vcpu, vcpu->arch.mmu.root_hpa);
2162 kvm_mmu_flush_tlb(vcpu);
2163 out:
2164 return r;
2165 }
2166 EXPORT_SYMBOL_GPL(kvm_mmu_load);
2167
2168 void kvm_mmu_unload(struct kvm_vcpu *vcpu)
2169 {
2170 mmu_free_roots(vcpu);
2171 }
2172
2173 static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
2174 struct kvm_mmu_page *sp,
2175 u64 *spte)
2176 {
2177 u64 pte;
2178 struct kvm_mmu_page *child;
2179
2180 pte = *spte;
2181 if (is_shadow_present_pte(pte)) {
2182 if (sp->role.level == PT_PAGE_TABLE_LEVEL ||
2183 is_large_pte(pte))
2184 rmap_remove(vcpu->kvm, spte);
2185 else {
2186 child = page_header(pte & PT64_BASE_ADDR_MASK);
2187 mmu_page_remove_parent_pte(child, spte);
2188 }
2189 }
2190 set_shadow_pte(spte, shadow_trap_nonpresent_pte);
2191 if (is_large_pte(pte))
2192 --vcpu->kvm->stat.lpages;
2193 }
2194
2195 static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
2196 struct kvm_mmu_page *sp,
2197 u64 *spte,
2198 const void *new)
2199 {
2200 if (sp->role.level != PT_PAGE_TABLE_LEVEL) {
2201 if (!vcpu->arch.update_pte.largepage ||
2202 sp->role.glevels == PT32_ROOT_LEVEL) {
2203 ++vcpu->kvm->stat.mmu_pde_zapped;
2204 return;
2205 }
2206 }
2207
2208 ++vcpu->kvm->stat.mmu_pte_updated;
2209 if (sp->role.glevels == PT32_ROOT_LEVEL)
2210 paging32_update_pte(vcpu, sp, spte, new);
2211 else
2212 paging64_update_pte(vcpu, sp, spte, new);
2213 }
2214
2215 static bool need_remote_flush(u64 old, u64 new)
2216 {
2217 if (!is_shadow_present_pte(old))
2218 return false;
2219 if (!is_shadow_present_pte(new))
2220 return true;
2221 if ((old ^ new) & PT64_BASE_ADDR_MASK)
2222 return true;
2223 old ^= PT64_NX_MASK;
2224 new ^= PT64_NX_MASK;
2225 return (old & ~new & PT64_PERM_MASK) != 0;
2226 }
2227
2228 static void mmu_pte_write_flush_tlb(struct kvm_vcpu *vcpu, u64 old, u64 new)
2229 {
2230 if (need_remote_flush(old, new))
2231 kvm_flush_remote_tlbs(vcpu->kvm);
2232 else
2233 kvm_mmu_flush_tlb(vcpu);
2234 }
2235
2236 static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu)
2237 {
2238 u64 *spte = vcpu->arch.last_pte_updated;
2239
2240 return !!(spte && (*spte & shadow_accessed_mask));
2241 }
2242
2243 static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
2244 const u8 *new, int bytes)
2245 {
2246 gfn_t gfn;
2247 int r;
2248 u64 gpte = 0;
2249 pfn_t pfn;
2250
2251 vcpu->arch.update_pte.largepage = 0;
2252
2253 if (bytes != 4 && bytes != 8)
2254 return;
2255
2256 /*
2257 * Assume that the pte write on a page table of the same type
2258 * as the current vcpu paging mode. This is nearly always true
2259 * (might be false while changing modes). Note it is verified later
2260 * by update_pte().
2261 */
2262 if (is_pae(vcpu)) {
2263 /* Handle a 32-bit guest writing two halves of a 64-bit gpte */
2264 if ((bytes == 4) && (gpa % 4 == 0)) {
2265 r = kvm_read_guest(vcpu->kvm, gpa & ~(u64)7, &gpte, 8);
2266 if (r)
2267 return;
2268 memcpy((void *)&gpte + (gpa % 8), new, 4);
2269 } else if ((bytes == 8) && (gpa % 8 == 0)) {
2270 memcpy((void *)&gpte, new, 8);
2271 }
2272 } else {
2273 if ((bytes == 4) && (gpa % 4 == 0))
2274 memcpy((void *)&gpte, new, 4);
2275 }
2276 if (!is_present_pte(gpte))
2277 return;
2278 gfn = (gpte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
2279
2280 if (is_large_pte(gpte) && is_largepage_backed(vcpu, gfn)) {
2281 gfn &= ~(KVM_PAGES_PER_HPAGE-1);
2282 vcpu->arch.update_pte.largepage = 1;
2283 }
2284 vcpu->arch.update_pte.mmu_seq = vcpu->kvm->mmu_notifier_seq;
2285 smp_rmb();
2286 pfn = gfn_to_pfn(vcpu->kvm, gfn);
2287
2288 if (is_error_pfn(pfn)) {
2289 kvm_release_pfn_clean(pfn);
2290 return;
2291 }
2292 vcpu->arch.update_pte.gfn = gfn;
2293 vcpu->arch.update_pte.pfn = pfn;
2294 }
2295
2296 static void kvm_mmu_access_page(struct kvm_vcpu *vcpu, gfn_t gfn)
2297 {
2298 u64 *spte = vcpu->arch.last_pte_updated;
2299
2300 if (spte
2301 && vcpu->arch.last_pte_gfn == gfn
2302 && shadow_accessed_mask
2303 && !(*spte & shadow_accessed_mask)
2304 && is_shadow_present_pte(*spte))
2305 set_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte);
2306 }
2307
2308 void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
2309 const u8 *new, int bytes)
2310 {
2311 gfn_t gfn = gpa >> PAGE_SHIFT;
2312 struct kvm_mmu_page *sp;
2313 struct hlist_node *node, *n;
2314 struct hlist_head *bucket;
2315 unsigned index;
2316 u64 entry, gentry;
2317 u64 *spte;
2318 unsigned offset = offset_in_page(gpa);
2319 unsigned pte_size;
2320 unsigned page_offset;
2321 unsigned misaligned;
2322 unsigned quadrant;
2323 int level;
2324 int flooded = 0;
2325 int npte;
2326 int r;
2327
2328 pgprintk("%s: gpa %llx bytes %d\n", __func__, gpa, bytes);
2329 mmu_guess_page_from_pte_write(vcpu, gpa, new, bytes);
2330 spin_lock(&vcpu->kvm->mmu_lock);
2331 kvm_mmu_access_page(vcpu, gfn);
2332 kvm_mmu_free_some_pages(vcpu);
2333 ++vcpu->kvm->stat.mmu_pte_write;
2334 kvm_mmu_audit(vcpu, "pre pte write");
2335 if (gfn == vcpu->arch.last_pt_write_gfn
2336 && !last_updated_pte_accessed(vcpu)) {
2337 ++vcpu->arch.last_pt_write_count;
2338 if (vcpu->arch.last_pt_write_count >= 3)
2339 flooded = 1;
2340 } else {
2341 vcpu->arch.last_pt_write_gfn = gfn;
2342 vcpu->arch.last_pt_write_count = 1;
2343 vcpu->arch.last_pte_updated = NULL;
2344 }
2345 index = kvm_page_table_hashfn(gfn);
2346 bucket = &vcpu->kvm->arch.mmu_page_hash[index];
2347 hlist_for_each_entry_safe(sp, node, n, bucket, hash_link) {
2348 if (sp->gfn != gfn || sp->role.metaphysical || sp->role.invalid)
2349 continue;
2350 pte_size = sp->role.glevels == PT32_ROOT_LEVEL ? 4 : 8;
2351 misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
2352 misaligned |= bytes < 4;
2353 if (misaligned || flooded) {
2354 /*
2355 * Misaligned accesses are too much trouble to fix
2356 * up; also, they usually indicate a page is not used
2357 * as a page table.
2358 *
2359 * If we're seeing too many writes to a page,
2360 * it may no longer be a page table, or we may be
2361 * forking, in which case it is better to unmap the
2362 * page.
2363 */
2364 pgprintk("misaligned: gpa %llx bytes %d role %x\n",
2365 gpa, bytes, sp->role.word);
2366 if (kvm_mmu_zap_page(vcpu->kvm, sp))
2367 n = bucket->first;
2368 ++vcpu->kvm->stat.mmu_flooded;
2369 continue;
2370 }
2371 page_offset = offset;
2372 level = sp->role.level;
2373 npte = 1;
2374 if (sp->role.glevels == PT32_ROOT_LEVEL) {
2375 page_offset <<= 1; /* 32->64 */
2376 /*
2377 * A 32-bit pde maps 4MB while the shadow pdes map
2378 * only 2MB. So we need to double the offset again
2379 * and zap two pdes instead of one.
2380 */
2381 if (level == PT32_ROOT_LEVEL) {
2382 page_offset &= ~7; /* kill rounding error */
2383 page_offset <<= 1;
2384 npte = 2;
2385 }
2386 quadrant = page_offset >> PAGE_SHIFT;
2387 page_offset &= ~PAGE_MASK;
2388 if (quadrant != sp->role.quadrant)
2389 continue;
2390 }
2391 spte = &sp->spt[page_offset / sizeof(*spte)];
2392 if ((gpa & (pte_size - 1)) || (bytes < pte_size)) {
2393 gentry = 0;
2394 r = kvm_read_guest_atomic(vcpu->kvm,
2395 gpa & ~(u64)(pte_size - 1),
2396 &gentry, pte_size);
2397 new = (const void *)&gentry;
2398 if (r < 0)
2399 new = NULL;
2400 }
2401 while (npte--) {
2402 entry = *spte;
2403 mmu_pte_write_zap_pte(vcpu, sp, spte);
2404 if (new)
2405 mmu_pte_write_new_pte(vcpu, sp, spte, new);
2406 mmu_pte_write_flush_tlb(vcpu, entry, *spte);
2407 ++spte;
2408 }
2409 }
2410 kvm_mmu_audit(vcpu, "post pte write");
2411 spin_unlock(&vcpu->kvm->mmu_lock);
2412 if (!is_error_pfn(vcpu->arch.update_pte.pfn)) {
2413 kvm_release_pfn_clean(vcpu->arch.update_pte.pfn);
2414 vcpu->arch.update_pte.pfn = bad_pfn;
2415 }
2416 }
2417
2418 int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
2419 {
2420 gpa_t gpa;
2421 int r;
2422
2423 gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva);
2424
2425 spin_lock(&vcpu->kvm->mmu_lock);
2426 r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
2427 spin_unlock(&vcpu->kvm->mmu_lock);
2428 return r;
2429 }
2430 EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page_virt);
2431
2432 void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
2433 {
2434 while (vcpu->kvm->arch.n_free_mmu_pages < KVM_REFILL_PAGES) {
2435 struct kvm_mmu_page *sp;
2436
2437 sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev,
2438 struct kvm_mmu_page, link);
2439 kvm_mmu_zap_page(vcpu->kvm, sp);
2440 ++vcpu->kvm->stat.mmu_recycled;
2441 }
2442 }
2443
2444 int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code)
2445 {
2446 int r;
2447 enum emulation_result er;
2448
2449 r = vcpu->arch.mmu.page_fault(vcpu, cr2, error_code);
2450 if (r < 0)
2451 goto out;
2452
2453 if (!r) {
2454 r = 1;
2455 goto out;
2456 }
2457
2458 r = mmu_topup_memory_caches(vcpu);
2459 if (r)
2460 goto out;
2461
2462 er = emulate_instruction(vcpu, vcpu->run, cr2, error_code, 0);
2463
2464 switch (er) {
2465 case EMULATE_DONE:
2466 return 1;
2467 case EMULATE_DO_MMIO:
2468 ++vcpu->stat.mmio_exits;
2469 return 0;
2470 case EMULATE_FAIL:
2471 kvm_report_emulation_failure(vcpu, "pagetable");
2472 return 1;
2473 default:
2474 BUG();
2475 }
2476 out:
2477 return r;
2478 }
2479 EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);
2480
2481 void kvm_mmu_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
2482 {
2483 spin_lock(&vcpu->kvm->mmu_lock);
2484 vcpu->arch.mmu.invlpg(vcpu, gva);
2485 spin_unlock(&vcpu->kvm->mmu_lock);
2486 kvm_mmu_flush_tlb(vcpu);
2487 ++vcpu->stat.invlpg;
2488 }
2489 EXPORT_SYMBOL_GPL(kvm_mmu_invlpg);
2490
2491 void kvm_enable_tdp(void)
2492 {
2493 tdp_enabled = true;
2494 }
2495 EXPORT_SYMBOL_GPL(kvm_enable_tdp);
2496
2497 void kvm_disable_tdp(void)
2498 {
2499 tdp_enabled = false;
2500 }
2501 EXPORT_SYMBOL_GPL(kvm_disable_tdp);
2502
2503 static void free_mmu_pages(struct kvm_vcpu *vcpu)
2504 {
2505 struct kvm_mmu_page *sp;
2506
2507 while (!list_empty(&vcpu->kvm->arch.active_mmu_pages)) {
2508 sp = container_of(vcpu->kvm->arch.active_mmu_pages.next,
2509 struct kvm_mmu_page, link);
2510 kvm_mmu_zap_page(vcpu->kvm, sp);
2511 cond_resched();
2512 }
2513 free_page((unsigned long)vcpu->arch.mmu.pae_root);
2514 }
2515
2516 static int alloc_mmu_pages(struct kvm_vcpu *vcpu)
2517 {
2518 struct page *page;
2519 int i;
2520
2521 ASSERT(vcpu);
2522
2523 if (vcpu->kvm->arch.n_requested_mmu_pages)
2524 vcpu->kvm->arch.n_free_mmu_pages =
2525 vcpu->kvm->arch.n_requested_mmu_pages;
2526 else
2527 vcpu->kvm->arch.n_free_mmu_pages =
2528 vcpu->kvm->arch.n_alloc_mmu_pages;
2529 /*
2530 * When emulating 32-bit mode, cr3 is only 32 bits even on x86_64.
2531 * Therefore we need to allocate shadow page tables in the first
2532 * 4GB of memory, which happens to fit the DMA32 zone.
2533 */
2534 page = alloc_page(GFP_KERNEL | __GFP_DMA32);
2535 if (!page)
2536 goto error_1;
2537 vcpu->arch.mmu.pae_root = page_address(page);
2538 for (i = 0; i < 4; ++i)
2539 vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
2540
2541 return 0;
2542
2543 error_1:
2544 free_mmu_pages(vcpu);
2545 return -ENOMEM;
2546 }
2547
2548 int kvm_mmu_create(struct kvm_vcpu *vcpu)
2549 {
2550 ASSERT(vcpu);
2551 ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
2552
2553 return alloc_mmu_pages(vcpu);
2554 }
2555
2556 int kvm_mmu_setup(struct kvm_vcpu *vcpu)
2557 {
2558 ASSERT(vcpu);
2559 ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
2560
2561 return init_kvm_mmu(vcpu);
2562 }
2563
2564 void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
2565 {
2566 ASSERT(vcpu);
2567
2568 destroy_kvm_mmu(vcpu);
2569 free_mmu_pages(vcpu);
2570 mmu_free_memory_caches(vcpu);
2571 }
2572
2573 void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
2574 {
2575 struct kvm_mmu_page *sp;
2576
2577 spin_lock(&kvm->mmu_lock);
2578 list_for_each_entry(sp, &kvm->arch.active_mmu_pages, link) {
2579 int i;
2580 u64 *pt;
2581
2582 if (!test_bit(slot, sp->slot_bitmap))
2583 continue;
2584
2585 pt = sp->spt;
2586 for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
2587 /* avoid RMW */
2588 if (pt[i] & PT_WRITABLE_MASK)
2589 pt[i] &= ~PT_WRITABLE_MASK;
2590 }
2591 kvm_flush_remote_tlbs(kvm);
2592 spin_unlock(&kvm->mmu_lock);
2593 }
2594
2595 void kvm_mmu_zap_all(struct kvm *kvm)
2596 {
2597 struct kvm_mmu_page *sp, *node;
2598
2599 spin_lock(&kvm->mmu_lock);
2600 list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link)
2601 if (kvm_mmu_zap_page(kvm, sp))
2602 node = container_of(kvm->arch.active_mmu_pages.next,
2603 struct kvm_mmu_page, link);
2604 spin_unlock(&kvm->mmu_lock);
2605
2606 kvm_flush_remote_tlbs(kvm);
2607 }
2608
2609 static void kvm_mmu_remove_one_alloc_mmu_page(struct kvm *kvm)
2610 {
2611 struct kvm_mmu_page *page;
2612
2613 page = container_of(kvm->arch.active_mmu_pages.prev,
2614 struct kvm_mmu_page, link);
2615 kvm_mmu_zap_page(kvm, page);
2616 }
2617
2618 static int mmu_shrink(int nr_to_scan, gfp_t gfp_mask)
2619 {
2620 struct kvm *kvm;
2621 struct kvm *kvm_freed = NULL;
2622 int cache_count = 0;
2623
2624 spin_lock(&kvm_lock);
2625
2626 list_for_each_entry(kvm, &vm_list, vm_list) {
2627 int npages;
2628
2629 if (!down_read_trylock(&kvm->slots_lock))
2630 continue;
2631 spin_lock(&kvm->mmu_lock);
2632 npages = kvm->arch.n_alloc_mmu_pages -
2633 kvm->arch.n_free_mmu_pages;
2634 cache_count += npages;
2635 if (!kvm_freed && nr_to_scan > 0 && npages > 0) {
2636 kvm_mmu_remove_one_alloc_mmu_page(kvm);
2637 cache_count--;
2638 kvm_freed = kvm;
2639 }
2640 nr_to_scan--;
2641
2642 spin_unlock(&kvm->mmu_lock);
2643 up_read(&kvm->slots_lock);
2644 }
2645 if (kvm_freed)
2646 list_move_tail(&kvm_freed->vm_list, &vm_list);
2647
2648 spin_unlock(&kvm_lock);
2649
2650 return cache_count;
2651 }
2652
2653 static struct shrinker mmu_shrinker = {
2654 .shrink = mmu_shrink,
2655 .seeks = DEFAULT_SEEKS * 10,
2656 };
2657
2658 static void mmu_destroy_caches(void)
2659 {
2660 if (pte_chain_cache)
2661 kmem_cache_destroy(pte_chain_cache);
2662 if (rmap_desc_cache)
2663 kmem_cache_destroy(rmap_desc_cache);
2664 if (mmu_page_header_cache)
2665 kmem_cache_destroy(mmu_page_header_cache);
2666 }
2667
2668 void kvm_mmu_module_exit(void)
2669 {
2670 mmu_destroy_caches();
2671 unregister_shrinker(&mmu_shrinker);
2672 }
2673
2674 int kvm_mmu_module_init(void)
2675 {
2676 pte_chain_cache = kmem_cache_create("kvm_pte_chain",
2677 sizeof(struct kvm_pte_chain),
2678 0, 0, NULL);
2679 if (!pte_chain_cache)
2680 goto nomem;
2681 rmap_desc_cache = kmem_cache_create("kvm_rmap_desc",
2682 sizeof(struct kvm_rmap_desc),
2683 0, 0, NULL);
2684 if (!rmap_desc_cache)
2685 goto nomem;
2686
2687 mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
2688 sizeof(struct kvm_mmu_page),
2689 0, 0, NULL);
2690 if (!mmu_page_header_cache)
2691 goto nomem;
2692
2693 register_shrinker(&mmu_shrinker);
2694
2695 return 0;
2696
2697 nomem:
2698 mmu_destroy_caches();
2699 return -ENOMEM;
2700 }
2701
2702 /*
2703 * Caculate mmu pages needed for kvm.
2704 */
2705 unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
2706 {
2707 int i;
2708 unsigned int nr_mmu_pages;
2709 unsigned int nr_pages = 0;
2710
2711 for (i = 0; i < kvm->nmemslots; i++)
2712 nr_pages += kvm->memslots[i].npages;
2713
2714 nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000;
2715 nr_mmu_pages = max(nr_mmu_pages,
2716 (unsigned int) KVM_MIN_ALLOC_MMU_PAGES);
2717
2718 return nr_mmu_pages;
2719 }
2720
2721 static void *pv_mmu_peek_buffer(struct kvm_pv_mmu_op_buffer *buffer,
2722 unsigned len)
2723 {
2724 if (len > buffer->len)
2725 return NULL;
2726 return buffer->ptr;
2727 }
2728
2729 static void *pv_mmu_read_buffer(struct kvm_pv_mmu_op_buffer *buffer,
2730 unsigned len)
2731 {
2732 void *ret;
2733
2734 ret = pv_mmu_peek_buffer(buffer, len);
2735 if (!ret)
2736 return ret;
2737 buffer->ptr += len;
2738 buffer->len -= len;
2739 buffer->processed += len;
2740 return ret;
2741 }
2742
2743 static int kvm_pv_mmu_write(struct kvm_vcpu *vcpu,
2744 gpa_t addr, gpa_t value)
2745 {
2746 int bytes = 8;
2747 int r;
2748
2749 if (!is_long_mode(vcpu) && !is_pae(vcpu))
2750 bytes = 4;
2751
2752 r = mmu_topup_memory_caches(vcpu);
2753 if (r)
2754 return r;
2755
2756 if (!emulator_write_phys(vcpu, addr, &value, bytes))
2757 return -EFAULT;
2758
2759 return 1;
2760 }
2761
2762 static int kvm_pv_mmu_flush_tlb(struct kvm_vcpu *vcpu)
2763 {
2764 kvm_x86_ops->tlb_flush(vcpu);
2765 set_bit(KVM_REQ_MMU_SYNC, &vcpu->requests);
2766 return 1;
2767 }
2768
2769 static int kvm_pv_mmu_release_pt(struct kvm_vcpu *vcpu, gpa_t addr)
2770 {
2771 spin_lock(&vcpu->kvm->mmu_lock);
2772 mmu_unshadow(vcpu->kvm, addr >> PAGE_SHIFT);
2773 spin_unlock(&vcpu->kvm->mmu_lock);
2774 return 1;
2775 }
2776
2777 static int kvm_pv_mmu_op_one(struct kvm_vcpu *vcpu,
2778 struct kvm_pv_mmu_op_buffer *buffer)
2779 {
2780 struct kvm_mmu_op_header *header;
2781
2782 header = pv_mmu_peek_buffer(buffer, sizeof *header);
2783 if (!header)
2784 return 0;
2785 switch (header->op) {
2786 case KVM_MMU_OP_WRITE_PTE: {
2787 struct kvm_mmu_op_write_pte *wpte;
2788
2789 wpte = pv_mmu_read_buffer(buffer, sizeof *wpte);
2790 if (!wpte)
2791 return 0;
2792 return kvm_pv_mmu_write(vcpu, wpte->pte_phys,
2793 wpte->pte_val);
2794 }
2795 case KVM_MMU_OP_FLUSH_TLB: {
2796 struct kvm_mmu_op_flush_tlb *ftlb;
2797
2798 ftlb = pv_mmu_read_buffer(buffer, sizeof *ftlb);
2799 if (!ftlb)
2800 return 0;
2801 return kvm_pv_mmu_flush_tlb(vcpu);
2802 }
2803 case KVM_MMU_OP_RELEASE_PT: {
2804 struct kvm_mmu_op_release_pt *rpt;
2805
2806 rpt = pv_mmu_read_buffer(buffer, sizeof *rpt);
2807 if (!rpt)
2808 return 0;
2809 return kvm_pv_mmu_release_pt(vcpu, rpt->pt_phys);
2810 }
2811 default: return 0;
2812 }
2813 }
2814
2815 int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes,
2816 gpa_t addr, unsigned long *ret)
2817 {
2818 int r;
2819 struct kvm_pv_mmu_op_buffer *buffer = &vcpu->arch.mmu_op_buffer;
2820
2821 buffer->ptr = buffer->buf;
2822 buffer->len = min_t(unsigned long, bytes, sizeof buffer->buf);
2823 buffer->processed = 0;
2824
2825 r = kvm_read_guest(vcpu->kvm, addr, buffer->buf, buffer->len);
2826 if (r)
2827 goto out;
2828
2829 while (buffer->len) {
2830 r = kvm_pv_mmu_op_one(vcpu, buffer);
2831 if (r < 0)
2832 goto out;
2833 if (r == 0)
2834 break;
2835 }
2836
2837 r = 1;
2838 out:
2839 *ret = buffer->processed;
2840 return r;
2841 }
2842
2843 #ifdef AUDIT
2844
2845 static const char *audit_msg;
2846
2847 static gva_t canonicalize(gva_t gva)
2848 {
2849 #ifdef CONFIG_X86_64
2850 gva = (long long)(gva << 16) >> 16;
2851 #endif
2852 return gva;
2853 }
2854
2855 static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
2856 gva_t va, int level)
2857 {
2858 u64 *pt = __va(page_pte & PT64_BASE_ADDR_MASK);
2859 int i;
2860 gva_t va_delta = 1ul << (PAGE_SHIFT + 9 * (level - 1));
2861
2862 for (i = 0; i < PT64_ENT_PER_PAGE; ++i, va += va_delta) {
2863 u64 ent = pt[i];
2864
2865 if (ent == shadow_trap_nonpresent_pte)
2866 continue;
2867
2868 va = canonicalize(va);
2869 if (level > 1) {
2870 if (ent == shadow_notrap_nonpresent_pte)
2871 printk(KERN_ERR "audit: (%s) nontrapping pte"
2872 " in nonleaf level: levels %d gva %lx"
2873 " level %d pte %llx\n", audit_msg,
2874 vcpu->arch.mmu.root_level, va, level, ent);
2875
2876 audit_mappings_page(vcpu, ent, va, level - 1);
2877 } else {
2878 gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, va);
2879 hpa_t hpa = (hpa_t)gpa_to_pfn(vcpu, gpa) << PAGE_SHIFT;
2880
2881 if (is_shadow_present_pte(ent)
2882 && (ent & PT64_BASE_ADDR_MASK) != hpa)
2883 printk(KERN_ERR "xx audit error: (%s) levels %d"
2884 " gva %lx gpa %llx hpa %llx ent %llx %d\n",
2885 audit_msg, vcpu->arch.mmu.root_level,
2886 va, gpa, hpa, ent,
2887 is_shadow_present_pte(ent));
2888 else if (ent == shadow_notrap_nonpresent_pte
2889 && !is_error_hpa(hpa))
2890 printk(KERN_ERR "audit: (%s) notrap shadow,"
2891 " valid guest gva %lx\n", audit_msg, va);
2892 kvm_release_pfn_clean(pfn);
2893
2894 }
2895 }
2896 }
2897
2898 static void audit_mappings(struct kvm_vcpu *vcpu)
2899 {
2900 unsigned i;
2901
2902 if (vcpu->arch.mmu.root_level == 4)
2903 audit_mappings_page(vcpu, vcpu->arch.mmu.root_hpa, 0, 4);
2904 else
2905 for (i = 0; i < 4; ++i)
2906 if (vcpu->arch.mmu.pae_root[i] & PT_PRESENT_MASK)
2907 audit_mappings_page(vcpu,
2908 vcpu->arch.mmu.pae_root[i],
2909 i << 30,
2910 2);
2911 }
2912
2913 static int count_rmaps(struct kvm_vcpu *vcpu)
2914 {
2915 int nmaps = 0;
2916 int i, j, k;
2917
2918 for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
2919 struct kvm_memory_slot *m = &vcpu->kvm->memslots[i];
2920 struct kvm_rmap_desc *d;
2921
2922 for (j = 0; j < m->npages; ++j) {
2923 unsigned long *rmapp = &m->rmap[j];
2924
2925 if (!*rmapp)
2926 continue;
2927 if (!(*rmapp & 1)) {
2928 ++nmaps;
2929 continue;
2930 }
2931 d = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
2932 while (d) {
2933 for (k = 0; k < RMAP_EXT; ++k)
2934 if (d->shadow_ptes[k])
2935 ++nmaps;
2936 else
2937 break;
2938 d = d->more;
2939 }
2940 }
2941 }
2942 return nmaps;
2943 }
2944
2945 static int count_writable_mappings(struct kvm_vcpu *vcpu)
2946 {
2947 int nmaps = 0;
2948 struct kvm_mmu_page *sp;
2949 int i;
2950
2951 list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
2952 u64 *pt = sp->spt;
2953
2954 if (sp->role.level != PT_PAGE_TABLE_LEVEL)
2955 continue;
2956
2957 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
2958 u64 ent = pt[i];
2959
2960 if (!(ent & PT_PRESENT_MASK))
2961 continue;
2962 if (!(ent & PT_WRITABLE_MASK))
2963 continue;
2964 ++nmaps;
2965 }
2966 }
2967 return nmaps;
2968 }
2969
2970 static void audit_rmap(struct kvm_vcpu *vcpu)
2971 {
2972 int n_rmap = count_rmaps(vcpu);
2973 int n_actual = count_writable_mappings(vcpu);
2974
2975 if (n_rmap != n_actual)
2976 printk(KERN_ERR "%s: (%s) rmap %d actual %d\n",
2977 __func__, audit_msg, n_rmap, n_actual);
2978 }
2979
2980 static void audit_write_protection(struct kvm_vcpu *vcpu)
2981 {
2982 struct kvm_mmu_page *sp;
2983 struct kvm_memory_slot *slot;
2984 unsigned long *rmapp;
2985 gfn_t gfn;
2986
2987 list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
2988 if (sp->role.metaphysical)
2989 continue;
2990
2991 gfn = unalias_gfn(vcpu->kvm, sp->gfn);
2992 slot = gfn_to_memslot_unaliased(vcpu->kvm, sp->gfn);
2993 rmapp = &slot->rmap[gfn - slot->base_gfn];
2994 if (*rmapp)
2995 printk(KERN_ERR "%s: (%s) shadow page has writable"
2996 " mappings: gfn %lx role %x\n",
2997 __func__, audit_msg, sp->gfn,
2998 sp->role.word);
2999 }
3000 }
3001
3002 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg)
3003 {
3004 int olddbg = dbg;
3005
3006 dbg = 0;
3007 audit_msg = msg;
3008 audit_rmap(vcpu);
3009 audit_write_protection(vcpu);
3010 audit_mappings(vcpu);
3011 dbg = olddbg;
3012 }
3013
3014 #endif
Linux kernel - Deliverables
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