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KVM: MMU: Remove unused varialbe in rmap_next()
[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 #include "x86.h"
22 #include "kvm_cache_regs.h"
23
24 #include <linux/kvm_host.h>
25 #include <linux/types.h>
26 #include <linux/string.h>
27 #include <linux/mm.h>
28 #include <linux/highmem.h>
29 #include <linux/module.h>
30 #include <linux/swap.h>
31 #include <linux/hugetlb.h>
32 #include <linux/compiler.h>
33 #include <linux/srcu.h>
34 #include <linux/slab.h>
35
36 #include <asm/page.h>
37 #include <asm/cmpxchg.h>
38 #include <asm/io.h>
39 #include <asm/vmx.h>
40
41 /*
42 * When setting this variable to true it enables Two-Dimensional-Paging
43 * where the hardware walks 2 page tables:
44 * 1. the guest-virtual to guest-physical
45 * 2. while doing 1. it walks guest-physical to host-physical
46 * If the hardware supports that we don't need to do shadow paging.
47 */
48 bool tdp_enabled = false;
49
50 #undef MMU_DEBUG
51
52 #undef AUDIT
53
54 #ifdef AUDIT
55 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg);
56 #else
57 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg) {}
58 #endif
59
60 #ifdef MMU_DEBUG
61
62 #define pgprintk(x...) do { if (dbg) printk(x); } while (0)
63 #define rmap_printk(x...) do { if (dbg) printk(x); } while (0)
64
65 #else
66
67 #define pgprintk(x...) do { } while (0)
68 #define rmap_printk(x...) do { } while (0)
69
70 #endif
71
72 #if defined(MMU_DEBUG) || defined(AUDIT)
73 static int dbg = 0;
74 module_param(dbg, bool, 0644);
75 #endif
76
77 static int oos_shadow = 1;
78 module_param(oos_shadow, bool, 0644);
79
80 #ifndef MMU_DEBUG
81 #define ASSERT(x) do { } while (0)
82 #else
83 #define ASSERT(x) \
84 if (!(x)) { \
85 printk(KERN_WARNING "assertion failed %s:%d: %s\n", \
86 __FILE__, __LINE__, #x); \
87 }
88 #endif
89
90 #define PT_FIRST_AVAIL_BITS_SHIFT 9
91 #define PT64_SECOND_AVAIL_BITS_SHIFT 52
92
93 #define VALID_PAGE(x) ((x) != INVALID_PAGE)
94
95 #define PT64_LEVEL_BITS 9
96
97 #define PT64_LEVEL_SHIFT(level) \
98 (PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS)
99
100 #define PT64_LEVEL_MASK(level) \
101 (((1ULL << PT64_LEVEL_BITS) - 1) << PT64_LEVEL_SHIFT(level))
102
103 #define PT64_INDEX(address, level)\
104 (((address) >> PT64_LEVEL_SHIFT(level)) & ((1 << PT64_LEVEL_BITS) - 1))
105
106
107 #define PT32_LEVEL_BITS 10
108
109 #define PT32_LEVEL_SHIFT(level) \
110 (PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS)
111
112 #define PT32_LEVEL_MASK(level) \
113 (((1ULL << PT32_LEVEL_BITS) - 1) << PT32_LEVEL_SHIFT(level))
114 #define PT32_LVL_OFFSET_MASK(level) \
115 (PT32_BASE_ADDR_MASK & ((1ULL << (PAGE_SHIFT + (((level) - 1) \
116 * PT32_LEVEL_BITS))) - 1))
117
118 #define PT32_INDEX(address, level)\
119 (((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))
120
121
122 #define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))
123 #define PT64_DIR_BASE_ADDR_MASK \
124 (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))
125 #define PT64_LVL_ADDR_MASK(level) \
126 (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + (((level) - 1) \
127 * PT64_LEVEL_BITS))) - 1))
128 #define PT64_LVL_OFFSET_MASK(level) \
129 (PT64_BASE_ADDR_MASK & ((1ULL << (PAGE_SHIFT + (((level) - 1) \
130 * PT64_LEVEL_BITS))) - 1))
131
132 #define PT32_BASE_ADDR_MASK PAGE_MASK
133 #define PT32_DIR_BASE_ADDR_MASK \
134 (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
135 #define PT32_LVL_ADDR_MASK(level) \
136 (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + (((level) - 1) \
137 * PT32_LEVEL_BITS))) - 1))
138
139 #define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK \
140 | PT64_NX_MASK)
141
142 #define RMAP_EXT 4
143
144 #define ACC_EXEC_MASK 1
145 #define ACC_WRITE_MASK PT_WRITABLE_MASK
146 #define ACC_USER_MASK PT_USER_MASK
147 #define ACC_ALL (ACC_EXEC_MASK | ACC_WRITE_MASK | ACC_USER_MASK)
148
149 #include <trace/events/kvm.h>
150
151 #define CREATE_TRACE_POINTS
152 #include "mmutrace.h"
153
154 #define SPTE_HOST_WRITEABLE (1ULL << PT_FIRST_AVAIL_BITS_SHIFT)
155
156 #define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)
157
158 struct kvm_rmap_desc {
159 u64 *sptes[RMAP_EXT];
160 struct kvm_rmap_desc *more;
161 };
162
163 struct kvm_shadow_walk_iterator {
164 u64 addr;
165 hpa_t shadow_addr;
166 int level;
167 u64 *sptep;
168 unsigned index;
169 };
170
171 #define for_each_shadow_entry(_vcpu, _addr, _walker) \
172 for (shadow_walk_init(&(_walker), _vcpu, _addr); \
173 shadow_walk_okay(&(_walker)); \
174 shadow_walk_next(&(_walker)))
175
176 typedef int (*mmu_parent_walk_fn) (struct kvm_mmu_page *sp);
177
178 static struct kmem_cache *pte_chain_cache;
179 static struct kmem_cache *rmap_desc_cache;
180 static struct kmem_cache *mmu_page_header_cache;
181
182 static u64 __read_mostly shadow_trap_nonpresent_pte;
183 static u64 __read_mostly shadow_notrap_nonpresent_pte;
184 static u64 __read_mostly shadow_base_present_pte;
185 static u64 __read_mostly shadow_nx_mask;
186 static u64 __read_mostly shadow_x_mask; /* mutual exclusive with nx_mask */
187 static u64 __read_mostly shadow_user_mask;
188 static u64 __read_mostly shadow_accessed_mask;
189 static u64 __read_mostly shadow_dirty_mask;
190
191 static inline u64 rsvd_bits(int s, int e)
192 {
193 return ((1ULL << (e - s + 1)) - 1) << s;
194 }
195
196 void kvm_mmu_set_nonpresent_ptes(u64 trap_pte, u64 notrap_pte)
197 {
198 shadow_trap_nonpresent_pte = trap_pte;
199 shadow_notrap_nonpresent_pte = notrap_pte;
200 }
201 EXPORT_SYMBOL_GPL(kvm_mmu_set_nonpresent_ptes);
202
203 void kvm_mmu_set_base_ptes(u64 base_pte)
204 {
205 shadow_base_present_pte = base_pte;
206 }
207 EXPORT_SYMBOL_GPL(kvm_mmu_set_base_ptes);
208
209 void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
210 u64 dirty_mask, u64 nx_mask, u64 x_mask)
211 {
212 shadow_user_mask = user_mask;
213 shadow_accessed_mask = accessed_mask;
214 shadow_dirty_mask = dirty_mask;
215 shadow_nx_mask = nx_mask;
216 shadow_x_mask = x_mask;
217 }
218 EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);
219
220 static int is_write_protection(struct kvm_vcpu *vcpu)
221 {
222 return kvm_read_cr0_bits(vcpu, X86_CR0_WP);
223 }
224
225 static int is_cpuid_PSE36(void)
226 {
227 return 1;
228 }
229
230 static int is_nx(struct kvm_vcpu *vcpu)
231 {
232 return vcpu->arch.efer & EFER_NX;
233 }
234
235 static int is_shadow_present_pte(u64 pte)
236 {
237 return pte != shadow_trap_nonpresent_pte
238 && pte != shadow_notrap_nonpresent_pte;
239 }
240
241 static int is_large_pte(u64 pte)
242 {
243 return pte & PT_PAGE_SIZE_MASK;
244 }
245
246 static int is_writable_pte(unsigned long pte)
247 {
248 return pte & PT_WRITABLE_MASK;
249 }
250
251 static int is_dirty_gpte(unsigned long pte)
252 {
253 return pte & PT_DIRTY_MASK;
254 }
255
256 static int is_rmap_spte(u64 pte)
257 {
258 return is_shadow_present_pte(pte);
259 }
260
261 static int is_last_spte(u64 pte, int level)
262 {
263 if (level == PT_PAGE_TABLE_LEVEL)
264 return 1;
265 if (is_large_pte(pte))
266 return 1;
267 return 0;
268 }
269
270 static pfn_t spte_to_pfn(u64 pte)
271 {
272 return (pte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
273 }
274
275 static gfn_t pse36_gfn_delta(u32 gpte)
276 {
277 int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT;
278
279 return (gpte & PT32_DIR_PSE36_MASK) << shift;
280 }
281
282 static void __set_spte(u64 *sptep, u64 spte)
283 {
284 #ifdef CONFIG_X86_64
285 set_64bit((unsigned long *)sptep, spte);
286 #else
287 set_64bit((unsigned long long *)sptep, spte);
288 #endif
289 }
290
291 static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
292 struct kmem_cache *base_cache, int min)
293 {
294 void *obj;
295
296 if (cache->nobjs >= min)
297 return 0;
298 while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
299 obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
300 if (!obj)
301 return -ENOMEM;
302 cache->objects[cache->nobjs++] = obj;
303 }
304 return 0;
305 }
306
307 static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
308 {
309 while (mc->nobjs)
310 kfree(mc->objects[--mc->nobjs]);
311 }
312
313 static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
314 int min)
315 {
316 struct page *page;
317
318 if (cache->nobjs >= min)
319 return 0;
320 while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
321 page = alloc_page(GFP_KERNEL);
322 if (!page)
323 return -ENOMEM;
324 cache->objects[cache->nobjs++] = page_address(page);
325 }
326 return 0;
327 }
328
329 static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
330 {
331 while (mc->nobjs)
332 free_page((unsigned long)mc->objects[--mc->nobjs]);
333 }
334
335 static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
336 {
337 int r;
338
339 r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_chain_cache,
340 pte_chain_cache, 4);
341 if (r)
342 goto out;
343 r = mmu_topup_memory_cache(&vcpu->arch.mmu_rmap_desc_cache,
344 rmap_desc_cache, 4);
345 if (r)
346 goto out;
347 r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
348 if (r)
349 goto out;
350 r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
351 mmu_page_header_cache, 4);
352 out:
353 return r;
354 }
355
356 static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
357 {
358 mmu_free_memory_cache(&vcpu->arch.mmu_pte_chain_cache);
359 mmu_free_memory_cache(&vcpu->arch.mmu_rmap_desc_cache);
360 mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache);
361 mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache);
362 }
363
364 static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc,
365 size_t size)
366 {
367 void *p;
368
369 BUG_ON(!mc->nobjs);
370 p = mc->objects[--mc->nobjs];
371 return p;
372 }
373
374 static struct kvm_pte_chain *mmu_alloc_pte_chain(struct kvm_vcpu *vcpu)
375 {
376 return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_chain_cache,
377 sizeof(struct kvm_pte_chain));
378 }
379
380 static void mmu_free_pte_chain(struct kvm_pte_chain *pc)
381 {
382 kfree(pc);
383 }
384
385 static struct kvm_rmap_desc *mmu_alloc_rmap_desc(struct kvm_vcpu *vcpu)
386 {
387 return mmu_memory_cache_alloc(&vcpu->arch.mmu_rmap_desc_cache,
388 sizeof(struct kvm_rmap_desc));
389 }
390
391 static void mmu_free_rmap_desc(struct kvm_rmap_desc *rd)
392 {
393 kfree(rd);
394 }
395
396 /*
397 * Return the pointer to the largepage write count for a given
398 * gfn, handling slots that are not large page aligned.
399 */
400 static int *slot_largepage_idx(gfn_t gfn,
401 struct kvm_memory_slot *slot,
402 int level)
403 {
404 unsigned long idx;
405
406 idx = (gfn / KVM_PAGES_PER_HPAGE(level)) -
407 (slot->base_gfn / KVM_PAGES_PER_HPAGE(level));
408 return &slot->lpage_info[level - 2][idx].write_count;
409 }
410
411 static void account_shadowed(struct kvm *kvm, gfn_t gfn)
412 {
413 struct kvm_memory_slot *slot;
414 int *write_count;
415 int i;
416
417 gfn = unalias_gfn(kvm, gfn);
418
419 slot = gfn_to_memslot_unaliased(kvm, gfn);
420 for (i = PT_DIRECTORY_LEVEL;
421 i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
422 write_count = slot_largepage_idx(gfn, slot, i);
423 *write_count += 1;
424 }
425 }
426
427 static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn)
428 {
429 struct kvm_memory_slot *slot;
430 int *write_count;
431 int i;
432
433 gfn = unalias_gfn(kvm, gfn);
434 for (i = PT_DIRECTORY_LEVEL;
435 i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
436 slot = gfn_to_memslot_unaliased(kvm, gfn);
437 write_count = slot_largepage_idx(gfn, slot, i);
438 *write_count -= 1;
439 WARN_ON(*write_count < 0);
440 }
441 }
442
443 static int has_wrprotected_page(struct kvm *kvm,
444 gfn_t gfn,
445 int level)
446 {
447 struct kvm_memory_slot *slot;
448 int *largepage_idx;
449
450 gfn = unalias_gfn(kvm, gfn);
451 slot = gfn_to_memslot_unaliased(kvm, gfn);
452 if (slot) {
453 largepage_idx = slot_largepage_idx(gfn, slot, level);
454 return *largepage_idx;
455 }
456
457 return 1;
458 }
459
460 static int host_mapping_level(struct kvm *kvm, gfn_t gfn)
461 {
462 unsigned long page_size;
463 int i, ret = 0;
464
465 page_size = kvm_host_page_size(kvm, gfn);
466
467 for (i = PT_PAGE_TABLE_LEVEL;
468 i < (PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES); ++i) {
469 if (page_size >= KVM_HPAGE_SIZE(i))
470 ret = i;
471 else
472 break;
473 }
474
475 return ret;
476 }
477
478 static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn)
479 {
480 struct kvm_memory_slot *slot;
481 int host_level, level, max_level;
482
483 slot = gfn_to_memslot(vcpu->kvm, large_gfn);
484 if (slot && slot->dirty_bitmap)
485 return PT_PAGE_TABLE_LEVEL;
486
487 host_level = host_mapping_level(vcpu->kvm, large_gfn);
488
489 if (host_level == PT_PAGE_TABLE_LEVEL)
490 return host_level;
491
492 max_level = kvm_x86_ops->get_lpage_level() < host_level ?
493 kvm_x86_ops->get_lpage_level() : host_level;
494
495 for (level = PT_DIRECTORY_LEVEL; level <= max_level; ++level)
496 if (has_wrprotected_page(vcpu->kvm, large_gfn, level))
497 break;
498
499 return level - 1;
500 }
501
502 /*
503 * Take gfn and return the reverse mapping to it.
504 * Note: gfn must be unaliased before this function get called
505 */
506
507 static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int level)
508 {
509 struct kvm_memory_slot *slot;
510 unsigned long idx;
511
512 slot = gfn_to_memslot(kvm, gfn);
513 if (likely(level == PT_PAGE_TABLE_LEVEL))
514 return &slot->rmap[gfn - slot->base_gfn];
515
516 idx = (gfn / KVM_PAGES_PER_HPAGE(level)) -
517 (slot->base_gfn / KVM_PAGES_PER_HPAGE(level));
518
519 return &slot->lpage_info[level - 2][idx].rmap_pde;
520 }
521
522 /*
523 * Reverse mapping data structures:
524 *
525 * If rmapp bit zero is zero, then rmapp point to the shadw page table entry
526 * that points to page_address(page).
527 *
528 * If rmapp bit zero is one, (then rmap & ~1) points to a struct kvm_rmap_desc
529 * containing more mappings.
530 *
531 * Returns the number of rmap entries before the spte was added or zero if
532 * the spte was not added.
533 *
534 */
535 static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
536 {
537 struct kvm_mmu_page *sp;
538 struct kvm_rmap_desc *desc;
539 unsigned long *rmapp;
540 int i, count = 0;
541
542 if (!is_rmap_spte(*spte))
543 return count;
544 gfn = unalias_gfn(vcpu->kvm, gfn);
545 sp = page_header(__pa(spte));
546 sp->gfns[spte - sp->spt] = gfn;
547 rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);
548 if (!*rmapp) {
549 rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte);
550 *rmapp = (unsigned long)spte;
551 } else if (!(*rmapp & 1)) {
552 rmap_printk("rmap_add: %p %llx 1->many\n", spte, *spte);
553 desc = mmu_alloc_rmap_desc(vcpu);
554 desc->sptes[0] = (u64 *)*rmapp;
555 desc->sptes[1] = spte;
556 *rmapp = (unsigned long)desc | 1;
557 } else {
558 rmap_printk("rmap_add: %p %llx many->many\n", spte, *spte);
559 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
560 while (desc->sptes[RMAP_EXT-1] && desc->more) {
561 desc = desc->more;
562 count += RMAP_EXT;
563 }
564 if (desc->sptes[RMAP_EXT-1]) {
565 desc->more = mmu_alloc_rmap_desc(vcpu);
566 desc = desc->more;
567 }
568 for (i = 0; desc->sptes[i]; ++i)
569 ;
570 desc->sptes[i] = spte;
571 }
572 return count;
573 }
574
575 static void rmap_desc_remove_entry(unsigned long *rmapp,
576 struct kvm_rmap_desc *desc,
577 int i,
578 struct kvm_rmap_desc *prev_desc)
579 {
580 int j;
581
582 for (j = RMAP_EXT - 1; !desc->sptes[j] && j > i; --j)
583 ;
584 desc->sptes[i] = desc->sptes[j];
585 desc->sptes[j] = NULL;
586 if (j != 0)
587 return;
588 if (!prev_desc && !desc->more)
589 *rmapp = (unsigned long)desc->sptes[0];
590 else
591 if (prev_desc)
592 prev_desc->more = desc->more;
593 else
594 *rmapp = (unsigned long)desc->more | 1;
595 mmu_free_rmap_desc(desc);
596 }
597
598 static void rmap_remove(struct kvm *kvm, u64 *spte)
599 {
600 struct kvm_rmap_desc *desc;
601 struct kvm_rmap_desc *prev_desc;
602 struct kvm_mmu_page *sp;
603 pfn_t pfn;
604 unsigned long *rmapp;
605 int i;
606
607 if (!is_rmap_spte(*spte))
608 return;
609 sp = page_header(__pa(spte));
610 pfn = spte_to_pfn(*spte);
611 if (*spte & shadow_accessed_mask)
612 kvm_set_pfn_accessed(pfn);
613 if (is_writable_pte(*spte))
614 kvm_set_pfn_dirty(pfn);
615 rmapp = gfn_to_rmap(kvm, sp->gfns[spte - sp->spt], sp->role.level);
616 if (!*rmapp) {
617 printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte);
618 BUG();
619 } else if (!(*rmapp & 1)) {
620 rmap_printk("rmap_remove: %p %llx 1->0\n", spte, *spte);
621 if ((u64 *)*rmapp != spte) {
622 printk(KERN_ERR "rmap_remove: %p %llx 1->BUG\n",
623 spte, *spte);
624 BUG();
625 }
626 *rmapp = 0;
627 } else {
628 rmap_printk("rmap_remove: %p %llx many->many\n", spte, *spte);
629 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
630 prev_desc = NULL;
631 while (desc) {
632 for (i = 0; i < RMAP_EXT && desc->sptes[i]; ++i)
633 if (desc->sptes[i] == spte) {
634 rmap_desc_remove_entry(rmapp,
635 desc, i,
636 prev_desc);
637 return;
638 }
639 prev_desc = desc;
640 desc = desc->more;
641 }
642 pr_err("rmap_remove: %p %llx many->many\n", spte, *spte);
643 BUG();
644 }
645 }
646
647 static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte)
648 {
649 struct kvm_rmap_desc *desc;
650 u64 *prev_spte;
651 int i;
652
653 if (!*rmapp)
654 return NULL;
655 else if (!(*rmapp & 1)) {
656 if (!spte)
657 return (u64 *)*rmapp;
658 return NULL;
659 }
660 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
661 prev_spte = NULL;
662 while (desc) {
663 for (i = 0; i < RMAP_EXT && desc->sptes[i]; ++i) {
664 if (prev_spte == spte)
665 return desc->sptes[i];
666 prev_spte = desc->sptes[i];
667 }
668 desc = desc->more;
669 }
670 return NULL;
671 }
672
673 static int rmap_write_protect(struct kvm *kvm, u64 gfn)
674 {
675 unsigned long *rmapp;
676 u64 *spte;
677 int i, write_protected = 0;
678
679 gfn = unalias_gfn(kvm, gfn);
680 rmapp = gfn_to_rmap(kvm, gfn, PT_PAGE_TABLE_LEVEL);
681
682 spte = rmap_next(kvm, rmapp, NULL);
683 while (spte) {
684 BUG_ON(!spte);
685 BUG_ON(!(*spte & PT_PRESENT_MASK));
686 rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
687 if (is_writable_pte(*spte)) {
688 __set_spte(spte, *spte & ~PT_WRITABLE_MASK);
689 write_protected = 1;
690 }
691 spte = rmap_next(kvm, rmapp, spte);
692 }
693 if (write_protected) {
694 pfn_t pfn;
695
696 spte = rmap_next(kvm, rmapp, NULL);
697 pfn = spte_to_pfn(*spte);
698 kvm_set_pfn_dirty(pfn);
699 }
700
701 /* check for huge page mappings */
702 for (i = PT_DIRECTORY_LEVEL;
703 i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
704 rmapp = gfn_to_rmap(kvm, gfn, i);
705 spte = rmap_next(kvm, rmapp, NULL);
706 while (spte) {
707 BUG_ON(!spte);
708 BUG_ON(!(*spte & PT_PRESENT_MASK));
709 BUG_ON((*spte & (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK)) != (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK));
710 pgprintk("rmap_write_protect(large): spte %p %llx %lld\n", spte, *spte, gfn);
711 if (is_writable_pte(*spte)) {
712 rmap_remove(kvm, spte);
713 --kvm->stat.lpages;
714 __set_spte(spte, shadow_trap_nonpresent_pte);
715 spte = NULL;
716 write_protected = 1;
717 }
718 spte = rmap_next(kvm, rmapp, spte);
719 }
720 }
721
722 return write_protected;
723 }
724
725 static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp,
726 unsigned long data)
727 {
728 u64 *spte;
729 int need_tlb_flush = 0;
730
731 while ((spte = rmap_next(kvm, rmapp, NULL))) {
732 BUG_ON(!(*spte & PT_PRESENT_MASK));
733 rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", spte, *spte);
734 rmap_remove(kvm, spte);
735 __set_spte(spte, shadow_trap_nonpresent_pte);
736 need_tlb_flush = 1;
737 }
738 return need_tlb_flush;
739 }
740
741 static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp,
742 unsigned long data)
743 {
744 int need_flush = 0;
745 u64 *spte, new_spte;
746 pte_t *ptep = (pte_t *)data;
747 pfn_t new_pfn;
748
749 WARN_ON(pte_huge(*ptep));
750 new_pfn = pte_pfn(*ptep);
751 spte = rmap_next(kvm, rmapp, NULL);
752 while (spte) {
753 BUG_ON(!is_shadow_present_pte(*spte));
754 rmap_printk("kvm_set_pte_rmapp: spte %p %llx\n", spte, *spte);
755 need_flush = 1;
756 if (pte_write(*ptep)) {
757 rmap_remove(kvm, spte);
758 __set_spte(spte, shadow_trap_nonpresent_pte);
759 spte = rmap_next(kvm, rmapp, NULL);
760 } else {
761 new_spte = *spte &~ (PT64_BASE_ADDR_MASK);
762 new_spte |= (u64)new_pfn << PAGE_SHIFT;
763
764 new_spte &= ~PT_WRITABLE_MASK;
765 new_spte &= ~SPTE_HOST_WRITEABLE;
766 if (is_writable_pte(*spte))
767 kvm_set_pfn_dirty(spte_to_pfn(*spte));
768 __set_spte(spte, new_spte);
769 spte = rmap_next(kvm, rmapp, spte);
770 }
771 }
772 if (need_flush)
773 kvm_flush_remote_tlbs(kvm);
774
775 return 0;
776 }
777
778 static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
779 unsigned long data,
780 int (*handler)(struct kvm *kvm, unsigned long *rmapp,
781 unsigned long data))
782 {
783 int i, j;
784 int ret;
785 int retval = 0;
786 struct kvm_memslots *slots;
787
788 slots = kvm_memslots(kvm);
789
790 for (i = 0; i < slots->nmemslots; i++) {
791 struct kvm_memory_slot *memslot = &slots->memslots[i];
792 unsigned long start = memslot->userspace_addr;
793 unsigned long end;
794
795 end = start + (memslot->npages << PAGE_SHIFT);
796 if (hva >= start && hva < end) {
797 gfn_t gfn_offset = (hva - start) >> PAGE_SHIFT;
798
799 ret = handler(kvm, &memslot->rmap[gfn_offset], data);
800
801 for (j = 0; j < KVM_NR_PAGE_SIZES - 1; ++j) {
802 int idx = gfn_offset;
803 idx /= KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL + j);
804 ret |= handler(kvm,
805 &memslot->lpage_info[j][idx].rmap_pde,
806 data);
807 }
808 trace_kvm_age_page(hva, memslot, ret);
809 retval |= ret;
810 }
811 }
812
813 return retval;
814 }
815
816 int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
817 {
818 return kvm_handle_hva(kvm, hva, 0, kvm_unmap_rmapp);
819 }
820
821 void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
822 {
823 kvm_handle_hva(kvm, hva, (unsigned long)&pte, kvm_set_pte_rmapp);
824 }
825
826 static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
827 unsigned long data)
828 {
829 u64 *spte;
830 int young = 0;
831
832 /*
833 * Emulate the accessed bit for EPT, by checking if this page has
834 * an EPT mapping, and clearing it if it does. On the next access,
835 * a new EPT mapping will be established.
836 * This has some overhead, but not as much as the cost of swapping
837 * out actively used pages or breaking up actively used hugepages.
838 */
839 if (!shadow_accessed_mask)
840 return kvm_unmap_rmapp(kvm, rmapp, data);
841
842 spte = rmap_next(kvm, rmapp, NULL);
843 while (spte) {
844 int _young;
845 u64 _spte = *spte;
846 BUG_ON(!(_spte & PT_PRESENT_MASK));
847 _young = _spte & PT_ACCESSED_MASK;
848 if (_young) {
849 young = 1;
850 clear_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte);
851 }
852 spte = rmap_next(kvm, rmapp, spte);
853 }
854 return young;
855 }
856
857 #define RMAP_RECYCLE_THRESHOLD 1000
858
859 static void rmap_recycle(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
860 {
861 unsigned long *rmapp;
862 struct kvm_mmu_page *sp;
863
864 sp = page_header(__pa(spte));
865
866 gfn = unalias_gfn(vcpu->kvm, gfn);
867 rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);
868
869 kvm_unmap_rmapp(vcpu->kvm, rmapp, 0);
870 kvm_flush_remote_tlbs(vcpu->kvm);
871 }
872
873 int kvm_age_hva(struct kvm *kvm, unsigned long hva)
874 {
875 return kvm_handle_hva(kvm, hva, 0, kvm_age_rmapp);
876 }
877
878 #ifdef MMU_DEBUG
879 static int is_empty_shadow_page(u64 *spt)
880 {
881 u64 *pos;
882 u64 *end;
883
884 for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
885 if (is_shadow_present_pte(*pos)) {
886 printk(KERN_ERR "%s: %p %llx\n", __func__,
887 pos, *pos);
888 return 0;
889 }
890 return 1;
891 }
892 #endif
893
894 static void kvm_mmu_free_page(struct kvm *kvm, struct kvm_mmu_page *sp)
895 {
896 ASSERT(is_empty_shadow_page(sp->spt));
897 list_del(&sp->link);
898 __free_page(virt_to_page(sp->spt));
899 __free_page(virt_to_page(sp->gfns));
900 kfree(sp);
901 ++kvm->arch.n_free_mmu_pages;
902 }
903
904 static unsigned kvm_page_table_hashfn(gfn_t gfn)
905 {
906 return gfn & ((1 << KVM_MMU_HASH_SHIFT) - 1);
907 }
908
909 static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
910 u64 *parent_pte)
911 {
912 struct kvm_mmu_page *sp;
913
914 sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache, sizeof *sp);
915 sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
916 sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
917 set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
918 list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
919 bitmap_zero(sp->slot_bitmap, KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS);
920 sp->multimapped = 0;
921 sp->parent_pte = parent_pte;
922 --vcpu->kvm->arch.n_free_mmu_pages;
923 return sp;
924 }
925
926 static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
927 struct kvm_mmu_page *sp, u64 *parent_pte)
928 {
929 struct kvm_pte_chain *pte_chain;
930 struct hlist_node *node;
931 int i;
932
933 if (!parent_pte)
934 return;
935 if (!sp->multimapped) {
936 u64 *old = sp->parent_pte;
937
938 if (!old) {
939 sp->parent_pte = parent_pte;
940 return;
941 }
942 sp->multimapped = 1;
943 pte_chain = mmu_alloc_pte_chain(vcpu);
944 INIT_HLIST_HEAD(&sp->parent_ptes);
945 hlist_add_head(&pte_chain->link, &sp->parent_ptes);
946 pte_chain->parent_ptes[0] = old;
947 }
948 hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link) {
949 if (pte_chain->parent_ptes[NR_PTE_CHAIN_ENTRIES-1])
950 continue;
951 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i)
952 if (!pte_chain->parent_ptes[i]) {
953 pte_chain->parent_ptes[i] = parent_pte;
954 return;
955 }
956 }
957 pte_chain = mmu_alloc_pte_chain(vcpu);
958 BUG_ON(!pte_chain);
959 hlist_add_head(&pte_chain->link, &sp->parent_ptes);
960 pte_chain->parent_ptes[0] = parent_pte;
961 }
962
963 static void mmu_page_remove_parent_pte(struct kvm_mmu_page *sp,
964 u64 *parent_pte)
965 {
966 struct kvm_pte_chain *pte_chain;
967 struct hlist_node *node;
968 int i;
969
970 if (!sp->multimapped) {
971 BUG_ON(sp->parent_pte != parent_pte);
972 sp->parent_pte = NULL;
973 return;
974 }
975 hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
976 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
977 if (!pte_chain->parent_ptes[i])
978 break;
979 if (pte_chain->parent_ptes[i] != parent_pte)
980 continue;
981 while (i + 1 < NR_PTE_CHAIN_ENTRIES
982 && pte_chain->parent_ptes[i + 1]) {
983 pte_chain->parent_ptes[i]
984 = pte_chain->parent_ptes[i + 1];
985 ++i;
986 }
987 pte_chain->parent_ptes[i] = NULL;
988 if (i == 0) {
989 hlist_del(&pte_chain->link);
990 mmu_free_pte_chain(pte_chain);
991 if (hlist_empty(&sp->parent_ptes)) {
992 sp->multimapped = 0;
993 sp->parent_pte = NULL;
994 }
995 }
996 return;
997 }
998 BUG();
999 }
1000
1001
1002 static void mmu_parent_walk(struct kvm_mmu_page *sp, mmu_parent_walk_fn fn)
1003 {
1004 struct kvm_pte_chain *pte_chain;
1005 struct hlist_node *node;
1006 struct kvm_mmu_page *parent_sp;
1007 int i;
1008
1009 if (!sp->multimapped && sp->parent_pte) {
1010 parent_sp = page_header(__pa(sp->parent_pte));
1011 fn(parent_sp);
1012 mmu_parent_walk(parent_sp, fn);
1013 return;
1014 }
1015 hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
1016 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
1017 if (!pte_chain->parent_ptes[i])
1018 break;
1019 parent_sp = page_header(__pa(pte_chain->parent_ptes[i]));
1020 fn(parent_sp);
1021 mmu_parent_walk(parent_sp, fn);
1022 }
1023 }
1024
1025 static void kvm_mmu_update_unsync_bitmap(u64 *spte)
1026 {
1027 unsigned int index;
1028 struct kvm_mmu_page *sp = page_header(__pa(spte));
1029
1030 index = spte - sp->spt;
1031 if (!__test_and_set_bit(index, sp->unsync_child_bitmap))
1032 sp->unsync_children++;
1033 WARN_ON(!sp->unsync_children);
1034 }
1035
1036 static void kvm_mmu_update_parents_unsync(struct kvm_mmu_page *sp)
1037 {
1038 struct kvm_pte_chain *pte_chain;
1039 struct hlist_node *node;
1040 int i;
1041
1042 if (!sp->parent_pte)
1043 return;
1044
1045 if (!sp->multimapped) {
1046 kvm_mmu_update_unsync_bitmap(sp->parent_pte);
1047 return;
1048 }
1049
1050 hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
1051 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
1052 if (!pte_chain->parent_ptes[i])
1053 break;
1054 kvm_mmu_update_unsync_bitmap(pte_chain->parent_ptes[i]);
1055 }
1056 }
1057
1058 static int unsync_walk_fn(struct kvm_mmu_page *sp)
1059 {
1060 kvm_mmu_update_parents_unsync(sp);
1061 return 1;
1062 }
1063
1064 static void kvm_mmu_mark_parents_unsync(struct kvm_mmu_page *sp)
1065 {
1066 mmu_parent_walk(sp, unsync_walk_fn);
1067 kvm_mmu_update_parents_unsync(sp);
1068 }
1069
1070 static void nonpaging_prefetch_page(struct kvm_vcpu *vcpu,
1071 struct kvm_mmu_page *sp)
1072 {
1073 int i;
1074
1075 for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
1076 sp->spt[i] = shadow_trap_nonpresent_pte;
1077 }
1078
1079 static int nonpaging_sync_page(struct kvm_vcpu *vcpu,
1080 struct kvm_mmu_page *sp)
1081 {
1082 return 1;
1083 }
1084
1085 static void nonpaging_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
1086 {
1087 }
1088
1089 #define KVM_PAGE_ARRAY_NR 16
1090
1091 struct kvm_mmu_pages {
1092 struct mmu_page_and_offset {
1093 struct kvm_mmu_page *sp;
1094 unsigned int idx;
1095 } page[KVM_PAGE_ARRAY_NR];
1096 unsigned int nr;
1097 };
1098
1099 #define for_each_unsync_children(bitmap, idx) \
1100 for (idx = find_first_bit(bitmap, 512); \
1101 idx < 512; \
1102 idx = find_next_bit(bitmap, 512, idx+1))
1103
1104 static int mmu_pages_add(struct kvm_mmu_pages *pvec, struct kvm_mmu_page *sp,
1105 int idx)
1106 {
1107 int i;
1108
1109 if (sp->unsync)
1110 for (i=0; i < pvec->nr; i++)
1111 if (pvec->page[i].sp == sp)
1112 return 0;
1113
1114 pvec->page[pvec->nr].sp = sp;
1115 pvec->page[pvec->nr].idx = idx;
1116 pvec->nr++;
1117 return (pvec->nr == KVM_PAGE_ARRAY_NR);
1118 }
1119
1120 static int __mmu_unsync_walk(struct kvm_mmu_page *sp,
1121 struct kvm_mmu_pages *pvec)
1122 {
1123 int i, ret, nr_unsync_leaf = 0;
1124
1125 for_each_unsync_children(sp->unsync_child_bitmap, i) {
1126 u64 ent = sp->spt[i];
1127
1128 if (is_shadow_present_pte(ent) && !is_large_pte(ent)) {
1129 struct kvm_mmu_page *child;
1130 child = page_header(ent & PT64_BASE_ADDR_MASK);
1131
1132 if (child->unsync_children) {
1133 if (mmu_pages_add(pvec, child, i))
1134 return -ENOSPC;
1135
1136 ret = __mmu_unsync_walk(child, pvec);
1137 if (!ret)
1138 __clear_bit(i, sp->unsync_child_bitmap);
1139 else if (ret > 0)
1140 nr_unsync_leaf += ret;
1141 else
1142 return ret;
1143 }
1144
1145 if (child->unsync) {
1146 nr_unsync_leaf++;
1147 if (mmu_pages_add(pvec, child, i))
1148 return -ENOSPC;
1149 }
1150 }
1151 }
1152
1153 if (find_first_bit(sp->unsync_child_bitmap, 512) == 512)
1154 sp->unsync_children = 0;
1155
1156 return nr_unsync_leaf;
1157 }
1158
1159 static int mmu_unsync_walk(struct kvm_mmu_page *sp,
1160 struct kvm_mmu_pages *pvec)
1161 {
1162 if (!sp->unsync_children)
1163 return 0;
1164
1165 mmu_pages_add(pvec, sp, 0);
1166 return __mmu_unsync_walk(sp, pvec);
1167 }
1168
1169 static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm *kvm, gfn_t gfn)
1170 {
1171 unsigned index;
1172 struct hlist_head *bucket;
1173 struct kvm_mmu_page *sp;
1174 struct hlist_node *node;
1175
1176 pgprintk("%s: looking for gfn %lx\n", __func__, gfn);
1177 index = kvm_page_table_hashfn(gfn);
1178 bucket = &kvm->arch.mmu_page_hash[index];
1179 hlist_for_each_entry(sp, node, bucket, hash_link)
1180 if (sp->gfn == gfn && !sp->role.direct
1181 && !sp->role.invalid) {
1182 pgprintk("%s: found role %x\n",
1183 __func__, sp->role.word);
1184 return sp;
1185 }
1186 return NULL;
1187 }
1188
1189 static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
1190 {
1191 WARN_ON(!sp->unsync);
1192 sp->unsync = 0;
1193 --kvm->stat.mmu_unsync;
1194 }
1195
1196 static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp);
1197
1198 static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
1199 {
1200 if (sp->role.cr4_pae != !!is_pae(vcpu)) {
1201 kvm_mmu_zap_page(vcpu->kvm, sp);
1202 return 1;
1203 }
1204
1205 trace_kvm_mmu_sync_page(sp);
1206 if (rmap_write_protect(vcpu->kvm, sp->gfn))
1207 kvm_flush_remote_tlbs(vcpu->kvm);
1208 kvm_unlink_unsync_page(vcpu->kvm, sp);
1209 if (vcpu->arch.mmu.sync_page(vcpu, sp)) {
1210 kvm_mmu_zap_page(vcpu->kvm, sp);
1211 return 1;
1212 }
1213
1214 kvm_mmu_flush_tlb(vcpu);
1215 return 0;
1216 }
1217
1218 struct mmu_page_path {
1219 struct kvm_mmu_page *parent[PT64_ROOT_LEVEL-1];
1220 unsigned int idx[PT64_ROOT_LEVEL-1];
1221 };
1222
1223 #define for_each_sp(pvec, sp, parents, i) \
1224 for (i = mmu_pages_next(&pvec, &parents, -1), \
1225 sp = pvec.page[i].sp; \
1226 i < pvec.nr && ({ sp = pvec.page[i].sp; 1;}); \
1227 i = mmu_pages_next(&pvec, &parents, i))
1228
1229 static int mmu_pages_next(struct kvm_mmu_pages *pvec,
1230 struct mmu_page_path *parents,
1231 int i)
1232 {
1233 int n;
1234
1235 for (n = i+1; n < pvec->nr; n++) {
1236 struct kvm_mmu_page *sp = pvec->page[n].sp;
1237
1238 if (sp->role.level == PT_PAGE_TABLE_LEVEL) {
1239 parents->idx[0] = pvec->page[n].idx;
1240 return n;
1241 }
1242
1243 parents->parent[sp->role.level-2] = sp;
1244 parents->idx[sp->role.level-1] = pvec->page[n].idx;
1245 }
1246
1247 return n;
1248 }
1249
1250 static void mmu_pages_clear_parents(struct mmu_page_path *parents)
1251 {
1252 struct kvm_mmu_page *sp;
1253 unsigned int level = 0;
1254
1255 do {
1256 unsigned int idx = parents->idx[level];
1257
1258 sp = parents->parent[level];
1259 if (!sp)
1260 return;
1261
1262 --sp->unsync_children;
1263 WARN_ON((int)sp->unsync_children < 0);
1264 __clear_bit(idx, sp->unsync_child_bitmap);
1265 level++;
1266 } while (level < PT64_ROOT_LEVEL-1 && !sp->unsync_children);
1267 }
1268
1269 static void kvm_mmu_pages_init(struct kvm_mmu_page *parent,
1270 struct mmu_page_path *parents,
1271 struct kvm_mmu_pages *pvec)
1272 {
1273 parents->parent[parent->role.level-1] = NULL;
1274 pvec->nr = 0;
1275 }
1276
1277 static void mmu_sync_children(struct kvm_vcpu *vcpu,
1278 struct kvm_mmu_page *parent)
1279 {
1280 int i;
1281 struct kvm_mmu_page *sp;
1282 struct mmu_page_path parents;
1283 struct kvm_mmu_pages pages;
1284
1285 kvm_mmu_pages_init(parent, &parents, &pages);
1286 while (mmu_unsync_walk(parent, &pages)) {
1287 int protected = 0;
1288
1289 for_each_sp(pages, sp, parents, i)
1290 protected |= rmap_write_protect(vcpu->kvm, sp->gfn);
1291
1292 if (protected)
1293 kvm_flush_remote_tlbs(vcpu->kvm);
1294
1295 for_each_sp(pages, sp, parents, i) {
1296 kvm_sync_page(vcpu, sp);
1297 mmu_pages_clear_parents(&parents);
1298 }
1299 cond_resched_lock(&vcpu->kvm->mmu_lock);
1300 kvm_mmu_pages_init(parent, &parents, &pages);
1301 }
1302 }
1303
1304 static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
1305 gfn_t gfn,
1306 gva_t gaddr,
1307 unsigned level,
1308 int direct,
1309 unsigned access,
1310 u64 *parent_pte)
1311 {
1312 union kvm_mmu_page_role role;
1313 unsigned index;
1314 unsigned quadrant;
1315 struct hlist_head *bucket;
1316 struct kvm_mmu_page *sp;
1317 struct hlist_node *node, *tmp;
1318
1319 role = vcpu->arch.mmu.base_role;
1320 role.level = level;
1321 role.direct = direct;
1322 if (role.direct)
1323 role.cr4_pae = 0;
1324 role.access = access;
1325 if (vcpu->arch.mmu.root_level <= PT32_ROOT_LEVEL) {
1326 quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
1327 quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
1328 role.quadrant = quadrant;
1329 }
1330 index = kvm_page_table_hashfn(gfn);
1331 bucket = &vcpu->kvm->arch.mmu_page_hash[index];
1332 hlist_for_each_entry_safe(sp, node, tmp, bucket, hash_link)
1333 if (sp->gfn == gfn) {
1334 if (sp->unsync)
1335 if (kvm_sync_page(vcpu, sp))
1336 continue;
1337
1338 if (sp->role.word != role.word)
1339 continue;
1340
1341 mmu_page_add_parent_pte(vcpu, sp, parent_pte);
1342 if (sp->unsync_children) {
1343 set_bit(KVM_REQ_MMU_SYNC, &vcpu->requests);
1344 kvm_mmu_mark_parents_unsync(sp);
1345 }
1346 trace_kvm_mmu_get_page(sp, false);
1347 return sp;
1348 }
1349 ++vcpu->kvm->stat.mmu_cache_miss;
1350 sp = kvm_mmu_alloc_page(vcpu, parent_pte);
1351 if (!sp)
1352 return sp;
1353 sp->gfn = gfn;
1354 sp->role = role;
1355 hlist_add_head(&sp->hash_link, bucket);
1356 if (!direct) {
1357 if (rmap_write_protect(vcpu->kvm, gfn))
1358 kvm_flush_remote_tlbs(vcpu->kvm);
1359 account_shadowed(vcpu->kvm, gfn);
1360 }
1361 if (shadow_trap_nonpresent_pte != shadow_notrap_nonpresent_pte)
1362 vcpu->arch.mmu.prefetch_page(vcpu, sp);
1363 else
1364 nonpaging_prefetch_page(vcpu, sp);
1365 trace_kvm_mmu_get_page(sp, true);
1366 return sp;
1367 }
1368
1369 static void shadow_walk_init(struct kvm_shadow_walk_iterator *iterator,
1370 struct kvm_vcpu *vcpu, u64 addr)
1371 {
1372 iterator->addr = addr;
1373 iterator->shadow_addr = vcpu->arch.mmu.root_hpa;
1374 iterator->level = vcpu->arch.mmu.shadow_root_level;
1375 if (iterator->level == PT32E_ROOT_LEVEL) {
1376 iterator->shadow_addr
1377 = vcpu->arch.mmu.pae_root[(addr >> 30) & 3];
1378 iterator->shadow_addr &= PT64_BASE_ADDR_MASK;
1379 --iterator->level;
1380 if (!iterator->shadow_addr)
1381 iterator->level = 0;
1382 }
1383 }
1384
1385 static bool shadow_walk_okay(struct kvm_shadow_walk_iterator *iterator)
1386 {
1387 if (iterator->level < PT_PAGE_TABLE_LEVEL)
1388 return false;
1389
1390 if (iterator->level == PT_PAGE_TABLE_LEVEL)
1391 if (is_large_pte(*iterator->sptep))
1392 return false;
1393
1394 iterator->index = SHADOW_PT_INDEX(iterator->addr, iterator->level);
1395 iterator->sptep = ((u64 *)__va(iterator->shadow_addr)) + iterator->index;
1396 return true;
1397 }
1398
1399 static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator)
1400 {
1401 iterator->shadow_addr = *iterator->sptep & PT64_BASE_ADDR_MASK;
1402 --iterator->level;
1403 }
1404
1405 static void kvm_mmu_page_unlink_children(struct kvm *kvm,
1406 struct kvm_mmu_page *sp)
1407 {
1408 unsigned i;
1409 u64 *pt;
1410 u64 ent;
1411
1412 pt = sp->spt;
1413
1414 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
1415 ent = pt[i];
1416
1417 if (is_shadow_present_pte(ent)) {
1418 if (!is_last_spte(ent, sp->role.level)) {
1419 ent &= PT64_BASE_ADDR_MASK;
1420 mmu_page_remove_parent_pte(page_header(ent),
1421 &pt[i]);
1422 } else {
1423 if (is_large_pte(ent))
1424 --kvm->stat.lpages;
1425 rmap_remove(kvm, &pt[i]);
1426 }
1427 }
1428 pt[i] = shadow_trap_nonpresent_pte;
1429 }
1430 }
1431
1432 static void kvm_mmu_put_page(struct kvm_mmu_page *sp, u64 *parent_pte)
1433 {
1434 mmu_page_remove_parent_pte(sp, parent_pte);
1435 }
1436
1437 static void kvm_mmu_reset_last_pte_updated(struct kvm *kvm)
1438 {
1439 int i;
1440 struct kvm_vcpu *vcpu;
1441
1442 kvm_for_each_vcpu(i, vcpu, kvm)
1443 vcpu->arch.last_pte_updated = NULL;
1444 }
1445
1446 static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp)
1447 {
1448 u64 *parent_pte;
1449
1450 while (sp->multimapped || sp->parent_pte) {
1451 if (!sp->multimapped)
1452 parent_pte = sp->parent_pte;
1453 else {
1454 struct kvm_pte_chain *chain;
1455
1456 chain = container_of(sp->parent_ptes.first,
1457 struct kvm_pte_chain, link);
1458 parent_pte = chain->parent_ptes[0];
1459 }
1460 BUG_ON(!parent_pte);
1461 kvm_mmu_put_page(sp, parent_pte);
1462 __set_spte(parent_pte, shadow_trap_nonpresent_pte);
1463 }
1464 }
1465
1466 static int mmu_zap_unsync_children(struct kvm *kvm,
1467 struct kvm_mmu_page *parent)
1468 {
1469 int i, zapped = 0;
1470 struct mmu_page_path parents;
1471 struct kvm_mmu_pages pages;
1472
1473 if (parent->role.level == PT_PAGE_TABLE_LEVEL)
1474 return 0;
1475
1476 kvm_mmu_pages_init(parent, &parents, &pages);
1477 while (mmu_unsync_walk(parent, &pages)) {
1478 struct kvm_mmu_page *sp;
1479
1480 for_each_sp(pages, sp, parents, i) {
1481 kvm_mmu_zap_page(kvm, sp);
1482 mmu_pages_clear_parents(&parents);
1483 zapped++;
1484 }
1485 kvm_mmu_pages_init(parent, &parents, &pages);
1486 }
1487
1488 return zapped;
1489 }
1490
1491 static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp)
1492 {
1493 int ret;
1494
1495 trace_kvm_mmu_zap_page(sp);
1496 ++kvm->stat.mmu_shadow_zapped;
1497 ret = mmu_zap_unsync_children(kvm, sp);
1498 kvm_mmu_page_unlink_children(kvm, sp);
1499 kvm_mmu_unlink_parents(kvm, sp);
1500 kvm_flush_remote_tlbs(kvm);
1501 if (!sp->role.invalid && !sp->role.direct)
1502 unaccount_shadowed(kvm, sp->gfn);
1503 if (sp->unsync)
1504 kvm_unlink_unsync_page(kvm, sp);
1505 if (!sp->root_count) {
1506 hlist_del(&sp->hash_link);
1507 kvm_mmu_free_page(kvm, sp);
1508 } else {
1509 sp->role.invalid = 1;
1510 list_move(&sp->link, &kvm->arch.active_mmu_pages);
1511 kvm_reload_remote_mmus(kvm);
1512 }
1513 kvm_mmu_reset_last_pte_updated(kvm);
1514 return ret;
1515 }
1516
1517 /*
1518 * Changing the number of mmu pages allocated to the vm
1519 * Note: if kvm_nr_mmu_pages is too small, you will get dead lock
1520 */
1521 void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages)
1522 {
1523 int used_pages;
1524
1525 used_pages = kvm->arch.n_alloc_mmu_pages - kvm->arch.n_free_mmu_pages;
1526 used_pages = max(0, used_pages);
1527
1528 /*
1529 * If we set the number of mmu pages to be smaller be than the
1530 * number of actived pages , we must to free some mmu pages before we
1531 * change the value
1532 */
1533
1534 if (used_pages > kvm_nr_mmu_pages) {
1535 while (used_pages > kvm_nr_mmu_pages &&
1536 !list_empty(&kvm->arch.active_mmu_pages)) {
1537 struct kvm_mmu_page *page;
1538
1539 page = container_of(kvm->arch.active_mmu_pages.prev,
1540 struct kvm_mmu_page, link);
1541 used_pages -= kvm_mmu_zap_page(kvm, page);
1542 used_pages--;
1543 }
1544 kvm_nr_mmu_pages = used_pages;
1545 kvm->arch.n_free_mmu_pages = 0;
1546 }
1547 else
1548 kvm->arch.n_free_mmu_pages += kvm_nr_mmu_pages
1549 - kvm->arch.n_alloc_mmu_pages;
1550
1551 kvm->arch.n_alloc_mmu_pages = kvm_nr_mmu_pages;
1552 }
1553
1554 static int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
1555 {
1556 unsigned index;
1557 struct hlist_head *bucket;
1558 struct kvm_mmu_page *sp;
1559 struct hlist_node *node, *n;
1560 int r;
1561
1562 pgprintk("%s: looking for gfn %lx\n", __func__, gfn);
1563 r = 0;
1564 index = kvm_page_table_hashfn(gfn);
1565 bucket = &kvm->arch.mmu_page_hash[index];
1566 restart:
1567 hlist_for_each_entry_safe(sp, node, n, bucket, hash_link)
1568 if (sp->gfn == gfn && !sp->role.direct) {
1569 pgprintk("%s: gfn %lx role %x\n", __func__, gfn,
1570 sp->role.word);
1571 r = 1;
1572 if (kvm_mmu_zap_page(kvm, sp))
1573 goto restart;
1574 }
1575 return r;
1576 }
1577
1578 static void mmu_unshadow(struct kvm *kvm, gfn_t gfn)
1579 {
1580 unsigned index;
1581 struct hlist_head *bucket;
1582 struct kvm_mmu_page *sp;
1583 struct hlist_node *node, *nn;
1584
1585 index = kvm_page_table_hashfn(gfn);
1586 bucket = &kvm->arch.mmu_page_hash[index];
1587 restart:
1588 hlist_for_each_entry_safe(sp, node, nn, bucket, hash_link) {
1589 if (sp->gfn == gfn && !sp->role.direct
1590 && !sp->role.invalid) {
1591 pgprintk("%s: zap %lx %x\n",
1592 __func__, gfn, sp->role.word);
1593 if (kvm_mmu_zap_page(kvm, sp))
1594 goto restart;
1595 }
1596 }
1597 }
1598
1599 static void page_header_update_slot(struct kvm *kvm, void *pte, gfn_t gfn)
1600 {
1601 int slot = memslot_id(kvm, gfn);
1602 struct kvm_mmu_page *sp = page_header(__pa(pte));
1603
1604 __set_bit(slot, sp->slot_bitmap);
1605 }
1606
1607 static void mmu_convert_notrap(struct kvm_mmu_page *sp)
1608 {
1609 int i;
1610 u64 *pt = sp->spt;
1611
1612 if (shadow_trap_nonpresent_pte == shadow_notrap_nonpresent_pte)
1613 return;
1614
1615 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
1616 if (pt[i] == shadow_notrap_nonpresent_pte)
1617 __set_spte(&pt[i], shadow_trap_nonpresent_pte);
1618 }
1619 }
1620
1621 struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva)
1622 {
1623 struct page *page;
1624
1625 gpa_t gpa = kvm_mmu_gva_to_gpa_read(vcpu, gva, NULL);
1626
1627 if (gpa == UNMAPPED_GVA)
1628 return NULL;
1629
1630 page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);
1631
1632 return page;
1633 }
1634
1635 /*
1636 * The function is based on mtrr_type_lookup() in
1637 * arch/x86/kernel/cpu/mtrr/generic.c
1638 */
1639 static int get_mtrr_type(struct mtrr_state_type *mtrr_state,
1640 u64 start, u64 end)
1641 {
1642 int i;
1643 u64 base, mask;
1644 u8 prev_match, curr_match;
1645 int num_var_ranges = KVM_NR_VAR_MTRR;
1646
1647 if (!mtrr_state->enabled)
1648 return 0xFF;
1649
1650 /* Make end inclusive end, instead of exclusive */
1651 end--;
1652
1653 /* Look in fixed ranges. Just return the type as per start */
1654 if (mtrr_state->have_fixed && (start < 0x100000)) {
1655 int idx;
1656
1657 if (start < 0x80000) {
1658 idx = 0;
1659 idx += (start >> 16);
1660 return mtrr_state->fixed_ranges[idx];
1661 } else if (start < 0xC0000) {
1662 idx = 1 * 8;
1663 idx += ((start - 0x80000) >> 14);
1664 return mtrr_state->fixed_ranges[idx];
1665 } else if (start < 0x1000000) {
1666 idx = 3 * 8;
1667 idx += ((start - 0xC0000) >> 12);
1668 return mtrr_state->fixed_ranges[idx];
1669 }
1670 }
1671
1672 /*
1673 * Look in variable ranges
1674 * Look of multiple ranges matching this address and pick type
1675 * as per MTRR precedence
1676 */
1677 if (!(mtrr_state->enabled & 2))
1678 return mtrr_state->def_type;
1679
1680 prev_match = 0xFF;
1681 for (i = 0; i < num_var_ranges; ++i) {
1682 unsigned short start_state, end_state;
1683
1684 if (!(mtrr_state->var_ranges[i].mask_lo & (1 << 11)))
1685 continue;
1686
1687 base = (((u64)mtrr_state->var_ranges[i].base_hi) << 32) +
1688 (mtrr_state->var_ranges[i].base_lo & PAGE_MASK);
1689 mask = (((u64)mtrr_state->var_ranges[i].mask_hi) << 32) +
1690 (mtrr_state->var_ranges[i].mask_lo & PAGE_MASK);
1691
1692 start_state = ((start & mask) == (base & mask));
1693 end_state = ((end & mask) == (base & mask));
1694 if (start_state != end_state)
1695 return 0xFE;
1696
1697 if ((start & mask) != (base & mask))
1698 continue;
1699
1700 curr_match = mtrr_state->var_ranges[i].base_lo & 0xff;
1701 if (prev_match == 0xFF) {
1702 prev_match = curr_match;
1703 continue;
1704 }
1705
1706 if (prev_match == MTRR_TYPE_UNCACHABLE ||
1707 curr_match == MTRR_TYPE_UNCACHABLE)
1708 return MTRR_TYPE_UNCACHABLE;
1709
1710 if ((prev_match == MTRR_TYPE_WRBACK &&
1711 curr_match == MTRR_TYPE_WRTHROUGH) ||
1712 (prev_match == MTRR_TYPE_WRTHROUGH &&
1713 curr_match == MTRR_TYPE_WRBACK)) {
1714 prev_match = MTRR_TYPE_WRTHROUGH;
1715 curr_match = MTRR_TYPE_WRTHROUGH;
1716 }
1717
1718 if (prev_match != curr_match)
1719 return MTRR_TYPE_UNCACHABLE;
1720 }
1721
1722 if (prev_match != 0xFF)
1723 return prev_match;
1724
1725 return mtrr_state->def_type;
1726 }
1727
1728 u8 kvm_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)
1729 {
1730 u8 mtrr;
1731
1732 mtrr = get_mtrr_type(&vcpu->arch.mtrr_state, gfn << PAGE_SHIFT,
1733 (gfn << PAGE_SHIFT) + PAGE_SIZE);
1734 if (mtrr == 0xfe || mtrr == 0xff)
1735 mtrr = MTRR_TYPE_WRBACK;
1736 return mtrr;
1737 }
1738 EXPORT_SYMBOL_GPL(kvm_get_guest_memory_type);
1739
1740 static int kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
1741 {
1742 unsigned index;
1743 struct hlist_head *bucket;
1744 struct kvm_mmu_page *s;
1745 struct hlist_node *node, *n;
1746
1747 trace_kvm_mmu_unsync_page(sp);
1748 index = kvm_page_table_hashfn(sp->gfn);
1749 bucket = &vcpu->kvm->arch.mmu_page_hash[index];
1750 /* don't unsync if pagetable is shadowed with multiple roles */
1751 hlist_for_each_entry_safe(s, node, n, bucket, hash_link) {
1752 if (s->gfn != sp->gfn || s->role.direct)
1753 continue;
1754 if (s->role.word != sp->role.word)
1755 return 1;
1756 }
1757 ++vcpu->kvm->stat.mmu_unsync;
1758 sp->unsync = 1;
1759
1760 kvm_mmu_mark_parents_unsync(sp);
1761
1762 mmu_convert_notrap(sp);
1763 return 0;
1764 }
1765
1766 static int mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn,
1767 bool can_unsync)
1768 {
1769 struct kvm_mmu_page *shadow;
1770
1771 shadow = kvm_mmu_lookup_page(vcpu->kvm, gfn);
1772 if (shadow) {
1773 if (shadow->role.level != PT_PAGE_TABLE_LEVEL)
1774 return 1;
1775 if (shadow->unsync)
1776 return 0;
1777 if (can_unsync && oos_shadow)
1778 return kvm_unsync_page(vcpu, shadow);
1779 return 1;
1780 }
1781 return 0;
1782 }
1783
1784 static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
1785 unsigned pte_access, int user_fault,
1786 int write_fault, int dirty, int level,
1787 gfn_t gfn, pfn_t pfn, bool speculative,
1788 bool can_unsync, bool reset_host_protection)
1789 {
1790 u64 spte;
1791 int ret = 0;
1792
1793 /*
1794 * We don't set the accessed bit, since we sometimes want to see
1795 * whether the guest actually used the pte (in order to detect
1796 * demand paging).
1797 */
1798 spte = shadow_base_present_pte | shadow_dirty_mask;
1799 if (!speculative)
1800 spte |= shadow_accessed_mask;
1801 if (!dirty)
1802 pte_access &= ~ACC_WRITE_MASK;
1803 if (pte_access & ACC_EXEC_MASK)
1804 spte |= shadow_x_mask;
1805 else
1806 spte |= shadow_nx_mask;
1807 if (pte_access & ACC_USER_MASK)
1808 spte |= shadow_user_mask;
1809 if (level > PT_PAGE_TABLE_LEVEL)
1810 spte |= PT_PAGE_SIZE_MASK;
1811 if (tdp_enabled)
1812 spte |= kvm_x86_ops->get_mt_mask(vcpu, gfn,
1813 kvm_is_mmio_pfn(pfn));
1814
1815 if (reset_host_protection)
1816 spte |= SPTE_HOST_WRITEABLE;
1817
1818 spte |= (u64)pfn << PAGE_SHIFT;
1819
1820 if ((pte_access & ACC_WRITE_MASK)
1821 || (write_fault && !is_write_protection(vcpu) && !user_fault)) {
1822
1823 if (level > PT_PAGE_TABLE_LEVEL &&
1824 has_wrprotected_page(vcpu->kvm, gfn, level)) {
1825 ret = 1;
1826 spte = shadow_trap_nonpresent_pte;
1827 goto set_pte;
1828 }
1829
1830 spte |= PT_WRITABLE_MASK;
1831
1832 /*
1833 * Optimization: for pte sync, if spte was writable the hash
1834 * lookup is unnecessary (and expensive). Write protection
1835 * is responsibility of mmu_get_page / kvm_sync_page.
1836 * Same reasoning can be applied to dirty page accounting.
1837 */
1838 if (!can_unsync && is_writable_pte(*sptep))
1839 goto set_pte;
1840
1841 if (mmu_need_write_protect(vcpu, gfn, can_unsync)) {
1842 pgprintk("%s: found shadow page for %lx, marking ro\n",
1843 __func__, gfn);
1844 ret = 1;
1845 pte_access &= ~ACC_WRITE_MASK;
1846 if (is_writable_pte(spte))
1847 spte &= ~PT_WRITABLE_MASK;
1848 }
1849 }
1850
1851 if (pte_access & ACC_WRITE_MASK)
1852 mark_page_dirty(vcpu->kvm, gfn);
1853
1854 set_pte:
1855 __set_spte(sptep, spte);
1856 return ret;
1857 }
1858
1859 static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
1860 unsigned pt_access, unsigned pte_access,
1861 int user_fault, int write_fault, int dirty,
1862 int *ptwrite, int level, gfn_t gfn,
1863 pfn_t pfn, bool speculative,
1864 bool reset_host_protection)
1865 {
1866 int was_rmapped = 0;
1867 int was_writable = is_writable_pte(*sptep);
1868 int rmap_count;
1869
1870 pgprintk("%s: spte %llx access %x write_fault %d"
1871 " user_fault %d gfn %lx\n",
1872 __func__, *sptep, pt_access,
1873 write_fault, user_fault, gfn);
1874
1875 if (is_rmap_spte(*sptep)) {
1876 /*
1877 * If we overwrite a PTE page pointer with a 2MB PMD, unlink
1878 * the parent of the now unreachable PTE.
1879 */
1880 if (level > PT_PAGE_TABLE_LEVEL &&
1881 !is_large_pte(*sptep)) {
1882 struct kvm_mmu_page *child;
1883 u64 pte = *sptep;
1884
1885 child = page_header(pte & PT64_BASE_ADDR_MASK);
1886 mmu_page_remove_parent_pte(child, sptep);
1887 } else if (pfn != spte_to_pfn(*sptep)) {
1888 pgprintk("hfn old %lx new %lx\n",
1889 spte_to_pfn(*sptep), pfn);
1890 rmap_remove(vcpu->kvm, sptep);
1891 } else
1892 was_rmapped = 1;
1893 }
1894
1895 if (set_spte(vcpu, sptep, pte_access, user_fault, write_fault,
1896 dirty, level, gfn, pfn, speculative, true,
1897 reset_host_protection)) {
1898 if (write_fault)
1899 *ptwrite = 1;
1900 kvm_x86_ops->tlb_flush(vcpu);
1901 }
1902
1903 pgprintk("%s: setting spte %llx\n", __func__, *sptep);
1904 pgprintk("instantiating %s PTE (%s) at %ld (%llx) addr %p\n",
1905 is_large_pte(*sptep)? "2MB" : "4kB",
1906 *sptep & PT_PRESENT_MASK ?"RW":"R", gfn,
1907 *sptep, sptep);
1908 if (!was_rmapped && is_large_pte(*sptep))
1909 ++vcpu->kvm->stat.lpages;
1910
1911 page_header_update_slot(vcpu->kvm, sptep, gfn);
1912 if (!was_rmapped) {
1913 rmap_count = rmap_add(vcpu, sptep, gfn);
1914 kvm_release_pfn_clean(pfn);
1915 if (rmap_count > RMAP_RECYCLE_THRESHOLD)
1916 rmap_recycle(vcpu, sptep, gfn);
1917 } else {
1918 if (was_writable)
1919 kvm_release_pfn_dirty(pfn);
1920 else
1921 kvm_release_pfn_clean(pfn);
1922 }
1923 if (speculative) {
1924 vcpu->arch.last_pte_updated = sptep;
1925 vcpu->arch.last_pte_gfn = gfn;
1926 }
1927 }
1928
1929 static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
1930 {
1931 }
1932
1933 static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
1934 int level, gfn_t gfn, pfn_t pfn)
1935 {
1936 struct kvm_shadow_walk_iterator iterator;
1937 struct kvm_mmu_page *sp;
1938 int pt_write = 0;
1939 gfn_t pseudo_gfn;
1940
1941 for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
1942 if (iterator.level == level) {
1943 mmu_set_spte(vcpu, iterator.sptep, ACC_ALL, ACC_ALL,
1944 0, write, 1, &pt_write,
1945 level, gfn, pfn, false, true);
1946 ++vcpu->stat.pf_fixed;
1947 break;
1948 }
1949
1950 if (*iterator.sptep == shadow_trap_nonpresent_pte) {
1951 pseudo_gfn = (iterator.addr & PT64_DIR_BASE_ADDR_MASK) >> PAGE_SHIFT;
1952 sp = kvm_mmu_get_page(vcpu, pseudo_gfn, iterator.addr,
1953 iterator.level - 1,
1954 1, ACC_ALL, iterator.sptep);
1955 if (!sp) {
1956 pgprintk("nonpaging_map: ENOMEM\n");
1957 kvm_release_pfn_clean(pfn);
1958 return -ENOMEM;
1959 }
1960
1961 __set_spte(iterator.sptep,
1962 __pa(sp->spt)
1963 | PT_PRESENT_MASK | PT_WRITABLE_MASK
1964 | shadow_user_mask | shadow_x_mask);
1965 }
1966 }
1967 return pt_write;
1968 }
1969
1970 static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
1971 {
1972 int r;
1973 int level;
1974 pfn_t pfn;
1975 unsigned long mmu_seq;
1976
1977 level = mapping_level(vcpu, gfn);
1978
1979 /*
1980 * This path builds a PAE pagetable - so we can map 2mb pages at
1981 * maximum. Therefore check if the level is larger than that.
1982 */
1983 if (level > PT_DIRECTORY_LEVEL)
1984 level = PT_DIRECTORY_LEVEL;
1985
1986 gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
1987
1988 mmu_seq = vcpu->kvm->mmu_notifier_seq;
1989 smp_rmb();
1990 pfn = gfn_to_pfn(vcpu->kvm, gfn);
1991
1992 /* mmio */
1993 if (is_error_pfn(pfn)) {
1994 kvm_release_pfn_clean(pfn);
1995 return 1;
1996 }
1997
1998 spin_lock(&vcpu->kvm->mmu_lock);
1999 if (mmu_notifier_retry(vcpu, mmu_seq))
2000 goto out_unlock;
2001 kvm_mmu_free_some_pages(vcpu);
2002 r = __direct_map(vcpu, v, write, level, gfn, pfn);
2003 spin_unlock(&vcpu->kvm->mmu_lock);
2004
2005
2006 return r;
2007
2008 out_unlock:
2009 spin_unlock(&vcpu->kvm->mmu_lock);
2010 kvm_release_pfn_clean(pfn);
2011 return 0;
2012 }
2013
2014
2015 static void mmu_free_roots(struct kvm_vcpu *vcpu)
2016 {
2017 int i;
2018 struct kvm_mmu_page *sp;
2019
2020 if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
2021 return;
2022 spin_lock(&vcpu->kvm->mmu_lock);
2023 if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
2024 hpa_t root = vcpu->arch.mmu.root_hpa;
2025
2026 sp = page_header(root);
2027 --sp->root_count;
2028 if (!sp->root_count && sp->role.invalid)
2029 kvm_mmu_zap_page(vcpu->kvm, sp);
2030 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
2031 spin_unlock(&vcpu->kvm->mmu_lock);
2032 return;
2033 }
2034 for (i = 0; i < 4; ++i) {
2035 hpa_t root = vcpu->arch.mmu.pae_root[i];
2036
2037 if (root) {
2038 root &= PT64_BASE_ADDR_MASK;
2039 sp = page_header(root);
2040 --sp->root_count;
2041 if (!sp->root_count && sp->role.invalid)
2042 kvm_mmu_zap_page(vcpu->kvm, sp);
2043 }
2044 vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
2045 }
2046 spin_unlock(&vcpu->kvm->mmu_lock);
2047 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
2048 }
2049
2050 static int mmu_check_root(struct kvm_vcpu *vcpu, gfn_t root_gfn)
2051 {
2052 int ret = 0;
2053
2054 if (!kvm_is_visible_gfn(vcpu->kvm, root_gfn)) {
2055 set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests);
2056 ret = 1;
2057 }
2058
2059 return ret;
2060 }
2061
2062 static int mmu_alloc_roots(struct kvm_vcpu *vcpu)
2063 {
2064 int i;
2065 gfn_t root_gfn;
2066 struct kvm_mmu_page *sp;
2067 int direct = 0;
2068 u64 pdptr;
2069
2070 root_gfn = vcpu->arch.cr3 >> PAGE_SHIFT;
2071
2072 if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
2073 hpa_t root = vcpu->arch.mmu.root_hpa;
2074
2075 ASSERT(!VALID_PAGE(root));
2076 if (tdp_enabled)
2077 direct = 1;
2078 if (mmu_check_root(vcpu, root_gfn))
2079 return 1;
2080 sp = kvm_mmu_get_page(vcpu, root_gfn, 0,
2081 PT64_ROOT_LEVEL, direct,
2082 ACC_ALL, NULL);
2083 root = __pa(sp->spt);
2084 ++sp->root_count;
2085 vcpu->arch.mmu.root_hpa = root;
2086 return 0;
2087 }
2088 direct = !is_paging(vcpu);
2089 if (tdp_enabled)
2090 direct = 1;
2091 for (i = 0; i < 4; ++i) {
2092 hpa_t root = vcpu->arch.mmu.pae_root[i];
2093
2094 ASSERT(!VALID_PAGE(root));
2095 if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
2096 pdptr = kvm_pdptr_read(vcpu, i);
2097 if (!is_present_gpte(pdptr)) {
2098 vcpu->arch.mmu.pae_root[i] = 0;
2099 continue;
2100 }
2101 root_gfn = pdptr >> PAGE_SHIFT;
2102 } else if (vcpu->arch.mmu.root_level == 0)
2103 root_gfn = 0;
2104 if (mmu_check_root(vcpu, root_gfn))
2105 return 1;
2106 sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
2107 PT32_ROOT_LEVEL, direct,
2108 ACC_ALL, NULL);
2109 root = __pa(sp->spt);
2110 ++sp->root_count;
2111 vcpu->arch.mmu.pae_root[i] = root | PT_PRESENT_MASK;
2112 }
2113 vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
2114 return 0;
2115 }
2116
2117 static void mmu_sync_roots(struct kvm_vcpu *vcpu)
2118 {
2119 int i;
2120 struct kvm_mmu_page *sp;
2121
2122 if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
2123 return;
2124 if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
2125 hpa_t root = vcpu->arch.mmu.root_hpa;
2126 sp = page_header(root);
2127 mmu_sync_children(vcpu, sp);
2128 return;
2129 }
2130 for (i = 0; i < 4; ++i) {
2131 hpa_t root = vcpu->arch.mmu.pae_root[i];
2132
2133 if (root && VALID_PAGE(root)) {
2134 root &= PT64_BASE_ADDR_MASK;
2135 sp = page_header(root);
2136 mmu_sync_children(vcpu, sp);
2137 }
2138 }
2139 }
2140
2141 void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
2142 {
2143 spin_lock(&vcpu->kvm->mmu_lock);
2144 mmu_sync_roots(vcpu);
2145 spin_unlock(&vcpu->kvm->mmu_lock);
2146 }
2147
2148 static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr,
2149 u32 access, u32 *error)
2150 {
2151 if (error)
2152 *error = 0;
2153 return vaddr;
2154 }
2155
2156 static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
2157 u32 error_code)
2158 {
2159 gfn_t gfn;
2160 int r;
2161
2162 pgprintk("%s: gva %lx error %x\n", __func__, gva, error_code);
2163 r = mmu_topup_memory_caches(vcpu);
2164 if (r)
2165 return r;
2166
2167 ASSERT(vcpu);
2168 ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
2169
2170 gfn = gva >> PAGE_SHIFT;
2171
2172 return nonpaging_map(vcpu, gva & PAGE_MASK,
2173 error_code & PFERR_WRITE_MASK, gfn);
2174 }
2175
2176 static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
2177 u32 error_code)
2178 {
2179 pfn_t pfn;
2180 int r;
2181 int level;
2182 gfn_t gfn = gpa >> PAGE_SHIFT;
2183 unsigned long mmu_seq;
2184
2185 ASSERT(vcpu);
2186 ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
2187
2188 r = mmu_topup_memory_caches(vcpu);
2189 if (r)
2190 return r;
2191
2192 level = mapping_level(vcpu, gfn);
2193
2194 gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
2195
2196 mmu_seq = vcpu->kvm->mmu_notifier_seq;
2197 smp_rmb();
2198 pfn = gfn_to_pfn(vcpu->kvm, gfn);
2199 if (is_error_pfn(pfn)) {
2200 kvm_release_pfn_clean(pfn);
2201 return 1;
2202 }
2203 spin_lock(&vcpu->kvm->mmu_lock);
2204 if (mmu_notifier_retry(vcpu, mmu_seq))
2205 goto out_unlock;
2206 kvm_mmu_free_some_pages(vcpu);
2207 r = __direct_map(vcpu, gpa, error_code & PFERR_WRITE_MASK,
2208 level, gfn, pfn);
2209 spin_unlock(&vcpu->kvm->mmu_lock);
2210
2211 return r;
2212
2213 out_unlock:
2214 spin_unlock(&vcpu->kvm->mmu_lock);
2215 kvm_release_pfn_clean(pfn);
2216 return 0;
2217 }
2218
2219 static void nonpaging_free(struct kvm_vcpu *vcpu)
2220 {
2221 mmu_free_roots(vcpu);
2222 }
2223
2224 static int nonpaging_init_context(struct kvm_vcpu *vcpu)
2225 {
2226 struct kvm_mmu *context = &vcpu->arch.mmu;
2227
2228 context->new_cr3 = nonpaging_new_cr3;
2229 context->page_fault = nonpaging_page_fault;
2230 context->gva_to_gpa = nonpaging_gva_to_gpa;
2231 context->free = nonpaging_free;
2232 context->prefetch_page = nonpaging_prefetch_page;
2233 context->sync_page = nonpaging_sync_page;
2234 context->invlpg = nonpaging_invlpg;
2235 context->root_level = 0;
2236 context->shadow_root_level = PT32E_ROOT_LEVEL;
2237 context->root_hpa = INVALID_PAGE;
2238 return 0;
2239 }
2240
2241 void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
2242 {
2243 ++vcpu->stat.tlb_flush;
2244 kvm_x86_ops->tlb_flush(vcpu);
2245 }
2246
2247 static void paging_new_cr3(struct kvm_vcpu *vcpu)
2248 {
2249 pgprintk("%s: cr3 %lx\n", __func__, vcpu->arch.cr3);
2250 mmu_free_roots(vcpu);
2251 }
2252
2253 static void inject_page_fault(struct kvm_vcpu *vcpu,
2254 u64 addr,
2255 u32 err_code)
2256 {
2257 kvm_inject_page_fault(vcpu, addr, err_code);
2258 }
2259
2260 static void paging_free(struct kvm_vcpu *vcpu)
2261 {
2262 nonpaging_free(vcpu);
2263 }
2264
2265 static bool is_rsvd_bits_set(struct kvm_vcpu *vcpu, u64 gpte, int level)
2266 {
2267 int bit7;
2268
2269 bit7 = (gpte >> 7) & 1;
2270 return (gpte & vcpu->arch.mmu.rsvd_bits_mask[bit7][level-1]) != 0;
2271 }
2272
2273 #define PTTYPE 64
2274 #include "paging_tmpl.h"
2275 #undef PTTYPE
2276
2277 #define PTTYPE 32
2278 #include "paging_tmpl.h"
2279 #undef PTTYPE
2280
2281 static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu, int level)
2282 {
2283 struct kvm_mmu *context = &vcpu->arch.mmu;
2284 int maxphyaddr = cpuid_maxphyaddr(vcpu);
2285 u64 exb_bit_rsvd = 0;
2286
2287 if (!is_nx(vcpu))
2288 exb_bit_rsvd = rsvd_bits(63, 63);
2289 switch (level) {
2290 case PT32_ROOT_LEVEL:
2291 /* no rsvd bits for 2 level 4K page table entries */
2292 context->rsvd_bits_mask[0][1] = 0;
2293 context->rsvd_bits_mask[0][0] = 0;
2294 context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
2295
2296 if (!is_pse(vcpu)) {
2297 context->rsvd_bits_mask[1][1] = 0;
2298 break;
2299 }
2300
2301 if (is_cpuid_PSE36())
2302 /* 36bits PSE 4MB page */
2303 context->rsvd_bits_mask[1][1] = rsvd_bits(17, 21);
2304 else
2305 /* 32 bits PSE 4MB page */
2306 context->rsvd_bits_mask[1][1] = rsvd_bits(13, 21);
2307 break;
2308 case PT32E_ROOT_LEVEL:
2309 context->rsvd_bits_mask[0][2] =
2310 rsvd_bits(maxphyaddr, 63) |
2311 rsvd_bits(7, 8) | rsvd_bits(1, 2); /* PDPTE */
2312 context->rsvd_bits_mask[0][1] = exb_bit_rsvd |
2313 rsvd_bits(maxphyaddr, 62); /* PDE */
2314 context->rsvd_bits_mask[0][0] = exb_bit_rsvd |
2315 rsvd_bits(maxphyaddr, 62); /* PTE */
2316 context->rsvd_bits_mask[1][1] = exb_bit_rsvd |
2317 rsvd_bits(maxphyaddr, 62) |
2318 rsvd_bits(13, 20); /* large page */
2319 context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
2320 break;
2321 case PT64_ROOT_LEVEL:
2322 context->rsvd_bits_mask[0][3] = exb_bit_rsvd |
2323 rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 8);
2324 context->rsvd_bits_mask[0][2] = exb_bit_rsvd |
2325 rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 8);
2326 context->rsvd_bits_mask[0][1] = exb_bit_rsvd |
2327 rsvd_bits(maxphyaddr, 51);
2328 context->rsvd_bits_mask[0][0] = exb_bit_rsvd |
2329 rsvd_bits(maxphyaddr, 51);
2330 context->rsvd_bits_mask[1][3] = context->rsvd_bits_mask[0][3];
2331 context->rsvd_bits_mask[1][2] = exb_bit_rsvd |
2332 rsvd_bits(maxphyaddr, 51) |
2333 rsvd_bits(13, 29);
2334 context->rsvd_bits_mask[1][1] = exb_bit_rsvd |
2335 rsvd_bits(maxphyaddr, 51) |
2336 rsvd_bits(13, 20); /* large page */
2337 context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
2338 break;
2339 }
2340 }
2341
2342 static int paging64_init_context_common(struct kvm_vcpu *vcpu, int level)
2343 {
2344 struct kvm_mmu *context = &vcpu->arch.mmu;
2345
2346 ASSERT(is_pae(vcpu));
2347 context->new_cr3 = paging_new_cr3;
2348 context->page_fault = paging64_page_fault;
2349 context->gva_to_gpa = paging64_gva_to_gpa;
2350 context->prefetch_page = paging64_prefetch_page;
2351 context->sync_page = paging64_sync_page;
2352 context->invlpg = paging64_invlpg;
2353 context->free = paging_free;
2354 context->root_level = level;
2355 context->shadow_root_level = level;
2356 context->root_hpa = INVALID_PAGE;
2357 return 0;
2358 }
2359
2360 static int paging64_init_context(struct kvm_vcpu *vcpu)
2361 {
2362 reset_rsvds_bits_mask(vcpu, PT64_ROOT_LEVEL);
2363 return paging64_init_context_common(vcpu, PT64_ROOT_LEVEL);
2364 }
2365
2366 static int paging32_init_context(struct kvm_vcpu *vcpu)
2367 {
2368 struct kvm_mmu *context = &vcpu->arch.mmu;
2369
2370 reset_rsvds_bits_mask(vcpu, PT32_ROOT_LEVEL);
2371 context->new_cr3 = paging_new_cr3;
2372 context->page_fault = paging32_page_fault;
2373 context->gva_to_gpa = paging32_gva_to_gpa;
2374 context->free = paging_free;
2375 context->prefetch_page = paging32_prefetch_page;
2376 context->sync_page = paging32_sync_page;
2377 context->invlpg = paging32_invlpg;
2378 context->root_level = PT32_ROOT_LEVEL;
2379 context->shadow_root_level = PT32E_ROOT_LEVEL;
2380 context->root_hpa = INVALID_PAGE;
2381 return 0;
2382 }
2383
2384 static int paging32E_init_context(struct kvm_vcpu *vcpu)
2385 {
2386 reset_rsvds_bits_mask(vcpu, PT32E_ROOT_LEVEL);
2387 return paging64_init_context_common(vcpu, PT32E_ROOT_LEVEL);
2388 }
2389
2390 static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
2391 {
2392 struct kvm_mmu *context = &vcpu->arch.mmu;
2393
2394 context->new_cr3 = nonpaging_new_cr3;
2395 context->page_fault = tdp_page_fault;
2396 context->free = nonpaging_free;
2397 context->prefetch_page = nonpaging_prefetch_page;
2398 context->sync_page = nonpaging_sync_page;
2399 context->invlpg = nonpaging_invlpg;
2400 context->shadow_root_level = kvm_x86_ops->get_tdp_level();
2401 context->root_hpa = INVALID_PAGE;
2402
2403 if (!is_paging(vcpu)) {
2404 context->gva_to_gpa = nonpaging_gva_to_gpa;
2405 context->root_level = 0;
2406 } else if (is_long_mode(vcpu)) {
2407 reset_rsvds_bits_mask(vcpu, PT64_ROOT_LEVEL);
2408 context->gva_to_gpa = paging64_gva_to_gpa;
2409 context->root_level = PT64_ROOT_LEVEL;
2410 } else if (is_pae(vcpu)) {
2411 reset_rsvds_bits_mask(vcpu, PT32E_ROOT_LEVEL);
2412 context->gva_to_gpa = paging64_gva_to_gpa;
2413 context->root_level = PT32E_ROOT_LEVEL;
2414 } else {
2415 reset_rsvds_bits_mask(vcpu, PT32_ROOT_LEVEL);
2416 context->gva_to_gpa = paging32_gva_to_gpa;
2417 context->root_level = PT32_ROOT_LEVEL;
2418 }
2419
2420 return 0;
2421 }
2422
2423 static int init_kvm_softmmu(struct kvm_vcpu *vcpu)
2424 {
2425 int r;
2426
2427 ASSERT(vcpu);
2428 ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
2429
2430 if (!is_paging(vcpu))
2431 r = nonpaging_init_context(vcpu);
2432 else if (is_long_mode(vcpu))
2433 r = paging64_init_context(vcpu);
2434 else if (is_pae(vcpu))
2435 r = paging32E_init_context(vcpu);
2436 else
2437 r = paging32_init_context(vcpu);
2438
2439 vcpu->arch.mmu.base_role.cr4_pae = !!is_pae(vcpu);
2440
2441 return r;
2442 }
2443
2444 static int init_kvm_mmu(struct kvm_vcpu *vcpu)
2445 {
2446 vcpu->arch.update_pte.pfn = bad_pfn;
2447
2448 if (tdp_enabled)
2449 return init_kvm_tdp_mmu(vcpu);
2450 else
2451 return init_kvm_softmmu(vcpu);
2452 }
2453
2454 static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
2455 {
2456 ASSERT(vcpu);
2457 if (VALID_PAGE(vcpu->arch.mmu.root_hpa)) {
2458 vcpu->arch.mmu.free(vcpu);
2459 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
2460 }
2461 }
2462
2463 int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
2464 {
2465 destroy_kvm_mmu(vcpu);
2466 return init_kvm_mmu(vcpu);
2467 }
2468 EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
2469
2470 int kvm_mmu_load(struct kvm_vcpu *vcpu)
2471 {
2472 int r;
2473
2474 r = mmu_topup_memory_caches(vcpu);
2475 if (r)
2476 goto out;
2477 spin_lock(&vcpu->kvm->mmu_lock);
2478 kvm_mmu_free_some_pages(vcpu);
2479 r = mmu_alloc_roots(vcpu);
2480 mmu_sync_roots(vcpu);
2481 spin_unlock(&vcpu->kvm->mmu_lock);
2482 if (r)
2483 goto out;
2484 /* set_cr3() should ensure TLB has been flushed */
2485 kvm_x86_ops->set_cr3(vcpu, vcpu->arch.mmu.root_hpa);
2486 out:
2487 return r;
2488 }
2489 EXPORT_SYMBOL_GPL(kvm_mmu_load);
2490
2491 void kvm_mmu_unload(struct kvm_vcpu *vcpu)
2492 {
2493 mmu_free_roots(vcpu);
2494 }
2495
2496 static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
2497 struct kvm_mmu_page *sp,
2498 u64 *spte)
2499 {
2500 u64 pte;
2501 struct kvm_mmu_page *child;
2502
2503 pte = *spte;
2504 if (is_shadow_present_pte(pte)) {
2505 if (is_last_spte(pte, sp->role.level))
2506 rmap_remove(vcpu->kvm, spte);
2507 else {
2508 child = page_header(pte & PT64_BASE_ADDR_MASK);
2509 mmu_page_remove_parent_pte(child, spte);
2510 }
2511 }
2512 __set_spte(spte, shadow_trap_nonpresent_pte);
2513 if (is_large_pte(pte))
2514 --vcpu->kvm->stat.lpages;
2515 }
2516
2517 static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
2518 struct kvm_mmu_page *sp,
2519 u64 *spte,
2520 const void *new)
2521 {
2522 if (sp->role.level != PT_PAGE_TABLE_LEVEL) {
2523 ++vcpu->kvm->stat.mmu_pde_zapped;
2524 return;
2525 }
2526
2527 ++vcpu->kvm->stat.mmu_pte_updated;
2528 if (!sp->role.cr4_pae)
2529 paging32_update_pte(vcpu, sp, spte, new);
2530 else
2531 paging64_update_pte(vcpu, sp, spte, new);
2532 }
2533
2534 static bool need_remote_flush(u64 old, u64 new)
2535 {
2536 if (!is_shadow_present_pte(old))
2537 return false;
2538 if (!is_shadow_present_pte(new))
2539 return true;
2540 if ((old ^ new) & PT64_BASE_ADDR_MASK)
2541 return true;
2542 old ^= PT64_NX_MASK;
2543 new ^= PT64_NX_MASK;
2544 return (old & ~new & PT64_PERM_MASK) != 0;
2545 }
2546
2547 static void mmu_pte_write_flush_tlb(struct kvm_vcpu *vcpu, u64 old, u64 new)
2548 {
2549 if (need_remote_flush(old, new))
2550 kvm_flush_remote_tlbs(vcpu->kvm);
2551 else
2552 kvm_mmu_flush_tlb(vcpu);
2553 }
2554
2555 static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu)
2556 {
2557 u64 *spte = vcpu->arch.last_pte_updated;
2558
2559 return !!(spte && (*spte & shadow_accessed_mask));
2560 }
2561
2562 static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
2563 u64 gpte)
2564 {
2565 gfn_t gfn;
2566 pfn_t pfn;
2567
2568 if (!is_present_gpte(gpte))
2569 return;
2570 gfn = (gpte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
2571
2572 vcpu->arch.update_pte.mmu_seq = vcpu->kvm->mmu_notifier_seq;
2573 smp_rmb();
2574 pfn = gfn_to_pfn(vcpu->kvm, gfn);
2575
2576 if (is_error_pfn(pfn)) {
2577 kvm_release_pfn_clean(pfn);
2578 return;
2579 }
2580 vcpu->arch.update_pte.gfn = gfn;
2581 vcpu->arch.update_pte.pfn = pfn;
2582 }
2583
2584 static void kvm_mmu_access_page(struct kvm_vcpu *vcpu, gfn_t gfn)
2585 {
2586 u64 *spte = vcpu->arch.last_pte_updated;
2587
2588 if (spte
2589 && vcpu->arch.last_pte_gfn == gfn
2590 && shadow_accessed_mask
2591 && !(*spte & shadow_accessed_mask)
2592 && is_shadow_present_pte(*spte))
2593 set_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte);
2594 }
2595
2596 void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
2597 const u8 *new, int bytes,
2598 bool guest_initiated)
2599 {
2600 gfn_t gfn = gpa >> PAGE_SHIFT;
2601 struct kvm_mmu_page *sp;
2602 struct hlist_node *node, *n;
2603 struct hlist_head *bucket;
2604 unsigned index;
2605 u64 entry, gentry;
2606 u64 *spte;
2607 unsigned offset = offset_in_page(gpa);
2608 unsigned pte_size;
2609 unsigned page_offset;
2610 unsigned misaligned;
2611 unsigned quadrant;
2612 int level;
2613 int flooded = 0;
2614 int npte;
2615 int r;
2616 int invlpg_counter;
2617
2618 pgprintk("%s: gpa %llx bytes %d\n", __func__, gpa, bytes);
2619
2620 invlpg_counter = atomic_read(&vcpu->kvm->arch.invlpg_counter);
2621
2622 /*
2623 * Assume that the pte write on a page table of the same type
2624 * as the current vcpu paging mode. This is nearly always true
2625 * (might be false while changing modes). Note it is verified later
2626 * by update_pte().
2627 */
2628 if ((is_pae(vcpu) && bytes == 4) || !new) {
2629 /* Handle a 32-bit guest writing two halves of a 64-bit gpte */
2630 if (is_pae(vcpu)) {
2631 gpa &= ~(gpa_t)7;
2632 bytes = 8;
2633 }
2634 r = kvm_read_guest(vcpu->kvm, gpa, &gentry, min(bytes, 8));
2635 if (r)
2636 gentry = 0;
2637 new = (const u8 *)&gentry;
2638 }
2639
2640 switch (bytes) {
2641 case 4:
2642 gentry = *(const u32 *)new;
2643 break;
2644 case 8:
2645 gentry = *(const u64 *)new;
2646 break;
2647 default:
2648 gentry = 0;
2649 break;
2650 }
2651
2652 mmu_guess_page_from_pte_write(vcpu, gpa, gentry);
2653 spin_lock(&vcpu->kvm->mmu_lock);
2654 if (atomic_read(&vcpu->kvm->arch.invlpg_counter) != invlpg_counter)
2655 gentry = 0;
2656 kvm_mmu_access_page(vcpu, gfn);
2657 kvm_mmu_free_some_pages(vcpu);
2658 ++vcpu->kvm->stat.mmu_pte_write;
2659 kvm_mmu_audit(vcpu, "pre pte write");
2660 if (guest_initiated) {
2661 if (gfn == vcpu->arch.last_pt_write_gfn
2662 && !last_updated_pte_accessed(vcpu)) {
2663 ++vcpu->arch.last_pt_write_count;
2664 if (vcpu->arch.last_pt_write_count >= 3)
2665 flooded = 1;
2666 } else {
2667 vcpu->arch.last_pt_write_gfn = gfn;
2668 vcpu->arch.last_pt_write_count = 1;
2669 vcpu->arch.last_pte_updated = NULL;
2670 }
2671 }
2672 index = kvm_page_table_hashfn(gfn);
2673 bucket = &vcpu->kvm->arch.mmu_page_hash[index];
2674
2675 restart:
2676 hlist_for_each_entry_safe(sp, node, n, bucket, hash_link) {
2677 if (sp->gfn != gfn || sp->role.direct || sp->role.invalid)
2678 continue;
2679 pte_size = sp->role.cr4_pae ? 8 : 4;
2680 misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
2681 misaligned |= bytes < 4;
2682 if (misaligned || flooded) {
2683 /*
2684 * Misaligned accesses are too much trouble to fix
2685 * up; also, they usually indicate a page is not used
2686 * as a page table.
2687 *
2688 * If we're seeing too many writes to a page,
2689 * it may no longer be a page table, or we may be
2690 * forking, in which case it is better to unmap the
2691 * page.
2692 */
2693 pgprintk("misaligned: gpa %llx bytes %d role %x\n",
2694 gpa, bytes, sp->role.word);
2695 if (kvm_mmu_zap_page(vcpu->kvm, sp))
2696 goto restart;
2697 ++vcpu->kvm->stat.mmu_flooded;
2698 continue;
2699 }
2700 page_offset = offset;
2701 level = sp->role.level;
2702 npte = 1;
2703 if (!sp->role.cr4_pae) {
2704 page_offset <<= 1; /* 32->64 */
2705 /*
2706 * A 32-bit pde maps 4MB while the shadow pdes map
2707 * only 2MB. So we need to double the offset again
2708 * and zap two pdes instead of one.
2709 */
2710 if (level == PT32_ROOT_LEVEL) {
2711 page_offset &= ~7; /* kill rounding error */
2712 page_offset <<= 1;
2713 npte = 2;
2714 }
2715 quadrant = page_offset >> PAGE_SHIFT;
2716 page_offset &= ~PAGE_MASK;
2717 if (quadrant != sp->role.quadrant)
2718 continue;
2719 }
2720 spte = &sp->spt[page_offset / sizeof(*spte)];
2721 while (npte--) {
2722 entry = *spte;
2723 mmu_pte_write_zap_pte(vcpu, sp, spte);
2724 if (gentry)
2725 mmu_pte_write_new_pte(vcpu, sp, spte, &gentry);
2726 mmu_pte_write_flush_tlb(vcpu, entry, *spte);
2727 ++spte;
2728 }
2729 }
2730 kvm_mmu_audit(vcpu, "post pte write");
2731 spin_unlock(&vcpu->kvm->mmu_lock);
2732 if (!is_error_pfn(vcpu->arch.update_pte.pfn)) {
2733 kvm_release_pfn_clean(vcpu->arch.update_pte.pfn);
2734 vcpu->arch.update_pte.pfn = bad_pfn;
2735 }
2736 }
2737
2738 int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
2739 {
2740 gpa_t gpa;
2741 int r;
2742
2743 if (tdp_enabled)
2744 return 0;
2745
2746 gpa = kvm_mmu_gva_to_gpa_read(vcpu, gva, NULL);
2747
2748 spin_lock(&vcpu->kvm->mmu_lock);
2749 r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
2750 spin_unlock(&vcpu->kvm->mmu_lock);
2751 return r;
2752 }
2753 EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page_virt);
2754
2755 void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
2756 {
2757 while (vcpu->kvm->arch.n_free_mmu_pages < KVM_REFILL_PAGES &&
2758 !list_empty(&vcpu->kvm->arch.active_mmu_pages)) {
2759 struct kvm_mmu_page *sp;
2760
2761 sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev,
2762 struct kvm_mmu_page, link);
2763 kvm_mmu_zap_page(vcpu->kvm, sp);
2764 ++vcpu->kvm->stat.mmu_recycled;
2765 }
2766 }
2767
2768 int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code)
2769 {
2770 int r;
2771 enum emulation_result er;
2772
2773 r = vcpu->arch.mmu.page_fault(vcpu, cr2, error_code);
2774 if (r < 0)
2775 goto out;
2776
2777 if (!r) {
2778 r = 1;
2779 goto out;
2780 }
2781
2782 r = mmu_topup_memory_caches(vcpu);
2783 if (r)
2784 goto out;
2785
2786 er = emulate_instruction(vcpu, cr2, error_code, 0);
2787
2788 switch (er) {
2789 case EMULATE_DONE:
2790 return 1;
2791 case EMULATE_DO_MMIO:
2792 ++vcpu->stat.mmio_exits;
2793 return 0;
2794 case EMULATE_FAIL:
2795 vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
2796 vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
2797 vcpu->run->internal.ndata = 0;
2798 return 0;
2799 default:
2800 BUG();
2801 }
2802 out:
2803 return r;
2804 }
2805 EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);
2806
2807 void kvm_mmu_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
2808 {
2809 vcpu->arch.mmu.invlpg(vcpu, gva);
2810 kvm_mmu_flush_tlb(vcpu);
2811 ++vcpu->stat.invlpg;
2812 }
2813 EXPORT_SYMBOL_GPL(kvm_mmu_invlpg);
2814
2815 void kvm_enable_tdp(void)
2816 {
2817 tdp_enabled = true;
2818 }
2819 EXPORT_SYMBOL_GPL(kvm_enable_tdp);
2820
2821 void kvm_disable_tdp(void)
2822 {
2823 tdp_enabled = false;
2824 }
2825 EXPORT_SYMBOL_GPL(kvm_disable_tdp);
2826
2827 static void free_mmu_pages(struct kvm_vcpu *vcpu)
2828 {
2829 free_page((unsigned long)vcpu->arch.mmu.pae_root);
2830 }
2831
2832 static int alloc_mmu_pages(struct kvm_vcpu *vcpu)
2833 {
2834 struct page *page;
2835 int i;
2836
2837 ASSERT(vcpu);
2838
2839 /*
2840 * When emulating 32-bit mode, cr3 is only 32 bits even on x86_64.
2841 * Therefore we need to allocate shadow page tables in the first
2842 * 4GB of memory, which happens to fit the DMA32 zone.
2843 */
2844 page = alloc_page(GFP_KERNEL | __GFP_DMA32);
2845 if (!page)
2846 return -ENOMEM;
2847
2848 vcpu->arch.mmu.pae_root = page_address(page);
2849 for (i = 0; i < 4; ++i)
2850 vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
2851
2852 return 0;
2853 }
2854
2855 int kvm_mmu_create(struct kvm_vcpu *vcpu)
2856 {
2857 ASSERT(vcpu);
2858 ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
2859
2860 return alloc_mmu_pages(vcpu);
2861 }
2862
2863 int kvm_mmu_setup(struct kvm_vcpu *vcpu)
2864 {
2865 ASSERT(vcpu);
2866 ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
2867
2868 return init_kvm_mmu(vcpu);
2869 }
2870
2871 void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
2872 {
2873 ASSERT(vcpu);
2874
2875 destroy_kvm_mmu(vcpu);
2876 free_mmu_pages(vcpu);
2877 mmu_free_memory_caches(vcpu);
2878 }
2879
2880 void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
2881 {
2882 struct kvm_mmu_page *sp;
2883
2884 list_for_each_entry(sp, &kvm->arch.active_mmu_pages, link) {
2885 int i;
2886 u64 *pt;
2887
2888 if (!test_bit(slot, sp->slot_bitmap))
2889 continue;
2890
2891 pt = sp->spt;
2892 for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
2893 /* avoid RMW */
2894 if (pt[i] & PT_WRITABLE_MASK)
2895 pt[i] &= ~PT_WRITABLE_MASK;
2896 }
2897 kvm_flush_remote_tlbs(kvm);
2898 }
2899
2900 void kvm_mmu_zap_all(struct kvm *kvm)
2901 {
2902 struct kvm_mmu_page *sp, *node;
2903
2904 spin_lock(&kvm->mmu_lock);
2905 restart:
2906 list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link)
2907 if (kvm_mmu_zap_page(kvm, sp))
2908 goto restart;
2909
2910 spin_unlock(&kvm->mmu_lock);
2911
2912 kvm_flush_remote_tlbs(kvm);
2913 }
2914
2915 static void kvm_mmu_remove_one_alloc_mmu_page(struct kvm *kvm)
2916 {
2917 struct kvm_mmu_page *page;
2918
2919 page = container_of(kvm->arch.active_mmu_pages.prev,
2920 struct kvm_mmu_page, link);
2921 kvm_mmu_zap_page(kvm, page);
2922 }
2923
2924 static int mmu_shrink(int nr_to_scan, gfp_t gfp_mask)
2925 {
2926 struct kvm *kvm;
2927 struct kvm *kvm_freed = NULL;
2928 int cache_count = 0;
2929
2930 spin_lock(&kvm_lock);
2931
2932 list_for_each_entry(kvm, &vm_list, vm_list) {
2933 int npages, idx;
2934
2935 idx = srcu_read_lock(&kvm->srcu);
2936 spin_lock(&kvm->mmu_lock);
2937 npages = kvm->arch.n_alloc_mmu_pages -
2938 kvm->arch.n_free_mmu_pages;
2939 cache_count += npages;
2940 if (!kvm_freed && nr_to_scan > 0 && npages > 0) {
2941 kvm_mmu_remove_one_alloc_mmu_page(kvm);
2942 cache_count--;
2943 kvm_freed = kvm;
2944 }
2945 nr_to_scan--;
2946
2947 spin_unlock(&kvm->mmu_lock);
2948 srcu_read_unlock(&kvm->srcu, idx);
2949 }
2950 if (kvm_freed)
2951 list_move_tail(&kvm_freed->vm_list, &vm_list);
2952
2953 spin_unlock(&kvm_lock);
2954
2955 return cache_count;
2956 }
2957
2958 static struct shrinker mmu_shrinker = {
2959 .shrink = mmu_shrink,
2960 .seeks = DEFAULT_SEEKS * 10,
2961 };
2962
2963 static void mmu_destroy_caches(void)
2964 {
2965 if (pte_chain_cache)
2966 kmem_cache_destroy(pte_chain_cache);
2967 if (rmap_desc_cache)
2968 kmem_cache_destroy(rmap_desc_cache);
2969 if (mmu_page_header_cache)
2970 kmem_cache_destroy(mmu_page_header_cache);
2971 }
2972
2973 void kvm_mmu_module_exit(void)
2974 {
2975 mmu_destroy_caches();
2976 unregister_shrinker(&mmu_shrinker);
2977 }
2978
2979 int kvm_mmu_module_init(void)
2980 {
2981 pte_chain_cache = kmem_cache_create("kvm_pte_chain",
2982 sizeof(struct kvm_pte_chain),
2983 0, 0, NULL);
2984 if (!pte_chain_cache)
2985 goto nomem;
2986 rmap_desc_cache = kmem_cache_create("kvm_rmap_desc",
2987 sizeof(struct kvm_rmap_desc),
2988 0, 0, NULL);
2989 if (!rmap_desc_cache)
2990 goto nomem;
2991
2992 mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
2993 sizeof(struct kvm_mmu_page),
2994 0, 0, NULL);
2995 if (!mmu_page_header_cache)
2996 goto nomem;
2997
2998 register_shrinker(&mmu_shrinker);
2999
3000 return 0;
3001
3002 nomem:
3003 mmu_destroy_caches();
3004 return -ENOMEM;
3005 }
3006
3007 /*
3008 * Caculate mmu pages needed for kvm.
3009 */
3010 unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
3011 {
3012 int i;
3013 unsigned int nr_mmu_pages;
3014 unsigned int nr_pages = 0;
3015 struct kvm_memslots *slots;
3016
3017 slots = kvm_memslots(kvm);
3018
3019 for (i = 0; i < slots->nmemslots; i++)
3020 nr_pages += slots->memslots[i].npages;
3021
3022 nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000;
3023 nr_mmu_pages = max(nr_mmu_pages,
3024 (unsigned int) KVM_MIN_ALLOC_MMU_PAGES);
3025
3026 return nr_mmu_pages;
3027 }
3028
3029 static void *pv_mmu_peek_buffer(struct kvm_pv_mmu_op_buffer *buffer,
3030 unsigned len)
3031 {
3032 if (len > buffer->len)
3033 return NULL;
3034 return buffer->ptr;
3035 }
3036
3037 static void *pv_mmu_read_buffer(struct kvm_pv_mmu_op_buffer *buffer,
3038 unsigned len)
3039 {
3040 void *ret;
3041
3042 ret = pv_mmu_peek_buffer(buffer, len);
3043 if (!ret)
3044 return ret;
3045 buffer->ptr += len;
3046 buffer->len -= len;
3047 buffer->processed += len;
3048 return ret;
3049 }
3050
3051 static int kvm_pv_mmu_write(struct kvm_vcpu *vcpu,
3052 gpa_t addr, gpa_t value)
3053 {
3054 int bytes = 8;
3055 int r;
3056
3057 if (!is_long_mode(vcpu) && !is_pae(vcpu))
3058 bytes = 4;
3059
3060 r = mmu_topup_memory_caches(vcpu);
3061 if (r)
3062 return r;
3063
3064 if (!emulator_write_phys(vcpu, addr, &value, bytes))
3065 return -EFAULT;
3066
3067 return 1;
3068 }
3069
3070 static int kvm_pv_mmu_flush_tlb(struct kvm_vcpu *vcpu)
3071 {
3072 kvm_set_cr3(vcpu, vcpu->arch.cr3);
3073 return 1;
3074 }
3075
3076 static int kvm_pv_mmu_release_pt(struct kvm_vcpu *vcpu, gpa_t addr)
3077 {
3078 spin_lock(&vcpu->kvm->mmu_lock);
3079 mmu_unshadow(vcpu->kvm, addr >> PAGE_SHIFT);
3080 spin_unlock(&vcpu->kvm->mmu_lock);
3081 return 1;
3082 }
3083
3084 static int kvm_pv_mmu_op_one(struct kvm_vcpu *vcpu,
3085 struct kvm_pv_mmu_op_buffer *buffer)
3086 {
3087 struct kvm_mmu_op_header *header;
3088
3089 header = pv_mmu_peek_buffer(buffer, sizeof *header);
3090 if (!header)
3091 return 0;
3092 switch (header->op) {
3093 case KVM_MMU_OP_WRITE_PTE: {
3094 struct kvm_mmu_op_write_pte *wpte;
3095
3096 wpte = pv_mmu_read_buffer(buffer, sizeof *wpte);
3097 if (!wpte)
3098 return 0;
3099 return kvm_pv_mmu_write(vcpu, wpte->pte_phys,
3100 wpte->pte_val);
3101 }
3102 case KVM_MMU_OP_FLUSH_TLB: {
3103 struct kvm_mmu_op_flush_tlb *ftlb;
3104
3105 ftlb = pv_mmu_read_buffer(buffer, sizeof *ftlb);
3106 if (!ftlb)
3107 return 0;
3108 return kvm_pv_mmu_flush_tlb(vcpu);
3109 }
3110 case KVM_MMU_OP_RELEASE_PT: {
3111 struct kvm_mmu_op_release_pt *rpt;
3112
3113 rpt = pv_mmu_read_buffer(buffer, sizeof *rpt);
3114 if (!rpt)
3115 return 0;
3116 return kvm_pv_mmu_release_pt(vcpu, rpt->pt_phys);
3117 }
3118 default: return 0;
3119 }
3120 }
3121
3122 int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes,
3123 gpa_t addr, unsigned long *ret)
3124 {
3125 int r;
3126 struct kvm_pv_mmu_op_buffer *buffer = &vcpu->arch.mmu_op_buffer;
3127
3128 buffer->ptr = buffer->buf;
3129 buffer->len = min_t(unsigned long, bytes, sizeof buffer->buf);
3130 buffer->processed = 0;
3131
3132 r = kvm_read_guest(vcpu->kvm, addr, buffer->buf, buffer->len);
3133 if (r)
3134 goto out;
3135
3136 while (buffer->len) {
3137 r = kvm_pv_mmu_op_one(vcpu, buffer);
3138 if (r < 0)
3139 goto out;
3140 if (r == 0)
3141 break;
3142 }
3143
3144 r = 1;
3145 out:
3146 *ret = buffer->processed;
3147 return r;
3148 }
3149
3150 int kvm_mmu_get_spte_hierarchy(struct kvm_vcpu *vcpu, u64 addr, u64 sptes[4])
3151 {
3152 struct kvm_shadow_walk_iterator iterator;
3153 int nr_sptes = 0;
3154
3155 spin_lock(&vcpu->kvm->mmu_lock);
3156 for_each_shadow_entry(vcpu, addr, iterator) {
3157 sptes[iterator.level-1] = *iterator.sptep;
3158 nr_sptes++;
3159 if (!is_shadow_present_pte(*iterator.sptep))
3160 break;
3161 }
3162 spin_unlock(&vcpu->kvm->mmu_lock);
3163
3164 return nr_sptes;
3165 }
3166 EXPORT_SYMBOL_GPL(kvm_mmu_get_spte_hierarchy);
3167
3168 #ifdef AUDIT
3169
3170 static const char *audit_msg;
3171
3172 static gva_t canonicalize(gva_t gva)
3173 {
3174 #ifdef CONFIG_X86_64
3175 gva = (long long)(gva << 16) >> 16;
3176 #endif
3177 return gva;
3178 }
3179
3180
3181 typedef void (*inspect_spte_fn) (struct kvm *kvm, u64 *sptep);
3182
3183 static void __mmu_spte_walk(struct kvm *kvm, struct kvm_mmu_page *sp,
3184 inspect_spte_fn fn)
3185 {
3186 int i;
3187
3188 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
3189 u64 ent = sp->spt[i];
3190
3191 if (is_shadow_present_pte(ent)) {
3192 if (!is_last_spte(ent, sp->role.level)) {
3193 struct kvm_mmu_page *child;
3194 child = page_header(ent & PT64_BASE_ADDR_MASK);
3195 __mmu_spte_walk(kvm, child, fn);
3196 } else
3197 fn(kvm, &sp->spt[i]);
3198 }
3199 }
3200 }
3201
3202 static void mmu_spte_walk(struct kvm_vcpu *vcpu, inspect_spte_fn fn)
3203 {
3204 int i;
3205 struct kvm_mmu_page *sp;
3206
3207 if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
3208 return;
3209 if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
3210 hpa_t root = vcpu->arch.mmu.root_hpa;
3211 sp = page_header(root);
3212 __mmu_spte_walk(vcpu->kvm, sp, fn);
3213 return;
3214 }
3215 for (i = 0; i < 4; ++i) {
3216 hpa_t root = vcpu->arch.mmu.pae_root[i];
3217
3218 if (root && VALID_PAGE(root)) {
3219 root &= PT64_BASE_ADDR_MASK;
3220 sp = page_header(root);
3221 __mmu_spte_walk(vcpu->kvm, sp, fn);
3222 }
3223 }
3224 return;
3225 }
3226
3227 static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
3228 gva_t va, int level)
3229 {
3230 u64 *pt = __va(page_pte & PT64_BASE_ADDR_MASK);
3231 int i;
3232 gva_t va_delta = 1ul << (PAGE_SHIFT + 9 * (level - 1));
3233
3234 for (i = 0; i < PT64_ENT_PER_PAGE; ++i, va += va_delta) {
3235 u64 ent = pt[i];
3236
3237 if (ent == shadow_trap_nonpresent_pte)
3238 continue;
3239
3240 va = canonicalize(va);
3241 if (is_shadow_present_pte(ent) && !is_last_spte(ent, level))
3242 audit_mappings_page(vcpu, ent, va, level - 1);
3243 else {
3244 gpa_t gpa = kvm_mmu_gva_to_gpa_read(vcpu, va, NULL);
3245 gfn_t gfn = gpa >> PAGE_SHIFT;
3246 pfn_t pfn = gfn_to_pfn(vcpu->kvm, gfn);
3247 hpa_t hpa = (hpa_t)pfn << PAGE_SHIFT;
3248
3249 if (is_error_pfn(pfn)) {
3250 kvm_release_pfn_clean(pfn);
3251 continue;
3252 }
3253
3254 if (is_shadow_present_pte(ent)
3255 && (ent & PT64_BASE_ADDR_MASK) != hpa)
3256 printk(KERN_ERR "xx audit error: (%s) levels %d"
3257 " gva %lx gpa %llx hpa %llx ent %llx %d\n",
3258 audit_msg, vcpu->arch.mmu.root_level,
3259 va, gpa, hpa, ent,
3260 is_shadow_present_pte(ent));
3261 else if (ent == shadow_notrap_nonpresent_pte
3262 && !is_error_hpa(hpa))
3263 printk(KERN_ERR "audit: (%s) notrap shadow,"
3264 " valid guest gva %lx\n", audit_msg, va);
3265 kvm_release_pfn_clean(pfn);
3266
3267 }
3268 }
3269 }
3270
3271 static void audit_mappings(struct kvm_vcpu *vcpu)
3272 {
3273 unsigned i;
3274
3275 if (vcpu->arch.mmu.root_level == 4)
3276 audit_mappings_page(vcpu, vcpu->arch.mmu.root_hpa, 0, 4);
3277 else
3278 for (i = 0; i < 4; ++i)
3279 if (vcpu->arch.mmu.pae_root[i] & PT_PRESENT_MASK)
3280 audit_mappings_page(vcpu,
3281 vcpu->arch.mmu.pae_root[i],
3282 i << 30,
3283 2);
3284 }
3285
3286 static int count_rmaps(struct kvm_vcpu *vcpu)
3287 {
3288 struct kvm *kvm = vcpu->kvm;
3289 struct kvm_memslots *slots;
3290 int nmaps = 0;
3291 int i, j, k, idx;
3292
3293 idx = srcu_read_lock(&kvm->srcu);
3294 slots = kvm_memslots(kvm);
3295 for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
3296 struct kvm_memory_slot *m = &slots->memslots[i];
3297 struct kvm_rmap_desc *d;
3298
3299 for (j = 0; j < m->npages; ++j) {
3300 unsigned long *rmapp = &m->rmap[j];
3301
3302 if (!*rmapp)
3303 continue;
3304 if (!(*rmapp & 1)) {
3305 ++nmaps;
3306 continue;
3307 }
3308 d = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
3309 while (d) {
3310 for (k = 0; k < RMAP_EXT; ++k)
3311 if (d->sptes[k])
3312 ++nmaps;
3313 else
3314 break;
3315 d = d->more;
3316 }
3317 }
3318 }
3319 srcu_read_unlock(&kvm->srcu, idx);
3320 return nmaps;
3321 }
3322
3323 void inspect_spte_has_rmap(struct kvm *kvm, u64 *sptep)
3324 {
3325 unsigned long *rmapp;
3326 struct kvm_mmu_page *rev_sp;
3327 gfn_t gfn;
3328
3329 if (*sptep & PT_WRITABLE_MASK) {
3330 rev_sp = page_header(__pa(sptep));
3331 gfn = rev_sp->gfns[sptep - rev_sp->spt];
3332
3333 if (!gfn_to_memslot(kvm, gfn)) {
3334 if (!printk_ratelimit())
3335 return;
3336 printk(KERN_ERR "%s: no memslot for gfn %ld\n",
3337 audit_msg, gfn);
3338 printk(KERN_ERR "%s: index %ld of sp (gfn=%lx)\n",
3339 audit_msg, (long int)(sptep - rev_sp->spt),
3340 rev_sp->gfn);
3341 dump_stack();
3342 return;
3343 }
3344
3345 rmapp = gfn_to_rmap(kvm, rev_sp->gfns[sptep - rev_sp->spt],
3346 rev_sp->role.level);
3347 if (!*rmapp) {
3348 if (!printk_ratelimit())
3349 return;
3350 printk(KERN_ERR "%s: no rmap for writable spte %llx\n",
3351 audit_msg, *sptep);
3352 dump_stack();
3353 }
3354 }
3355
3356 }
3357
3358 void audit_writable_sptes_have_rmaps(struct kvm_vcpu *vcpu)
3359 {
3360 mmu_spte_walk(vcpu, inspect_spte_has_rmap);
3361 }
3362
3363 static void check_writable_mappings_rmap(struct kvm_vcpu *vcpu)
3364 {
3365 struct kvm_mmu_page *sp;
3366 int i;
3367
3368 list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
3369 u64 *pt = sp->spt;
3370
3371 if (sp->role.level != PT_PAGE_TABLE_LEVEL)
3372 continue;
3373
3374 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
3375 u64 ent = pt[i];
3376
3377 if (!(ent & PT_PRESENT_MASK))
3378 continue;
3379 if (!(ent & PT_WRITABLE_MASK))
3380 continue;
3381 inspect_spte_has_rmap(vcpu->kvm, &pt[i]);
3382 }
3383 }
3384 return;
3385 }
3386
3387 static void audit_rmap(struct kvm_vcpu *vcpu)
3388 {
3389 check_writable_mappings_rmap(vcpu);
3390 count_rmaps(vcpu);
3391 }
3392
3393 static void audit_write_protection(struct kvm_vcpu *vcpu)
3394 {
3395 struct kvm_mmu_page *sp;
3396 struct kvm_memory_slot *slot;
3397 unsigned long *rmapp;
3398 u64 *spte;
3399 gfn_t gfn;
3400
3401 list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
3402 if (sp->role.direct)
3403 continue;
3404 if (sp->unsync)
3405 continue;
3406
3407 gfn = unalias_gfn(vcpu->kvm, sp->gfn);
3408 slot = gfn_to_memslot_unaliased(vcpu->kvm, sp->gfn);
3409 rmapp = &slot->rmap[gfn - slot->base_gfn];
3410
3411 spte = rmap_next(vcpu->kvm, rmapp, NULL);
3412 while (spte) {
3413 if (*spte & PT_WRITABLE_MASK)
3414 printk(KERN_ERR "%s: (%s) shadow page has "
3415 "writable mappings: gfn %lx role %x\n",
3416 __func__, audit_msg, sp->gfn,
3417 sp->role.word);
3418 spte = rmap_next(vcpu->kvm, rmapp, spte);
3419 }
3420 }
3421 }
3422
3423 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg)
3424 {
3425 int olddbg = dbg;
3426
3427 dbg = 0;
3428 audit_msg = msg;
3429 audit_rmap(vcpu);
3430 audit_write_protection(vcpu);
3431 if (strcmp("pre pte write", audit_msg) != 0)
3432 audit_mappings(vcpu);
3433 audit_writable_sptes_have_rmaps(vcpu);
3434 dbg = olddbg;
3435 }
3436
3437 #endif
Linux kernel - Deliverables
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