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KVM: MMU: Move nonpaging_prefetch_page()
[linux-2.6/linux-2.6-openrd.git] / arch / x86 / kvm / mmu.c
blob62741b7c4223adf2deb0fc8deb3fa0939f0f8cc2
1 /*
2 * Kernel-based Virtual Machine driver for Linux
3 *
4 * This module enables machines with Intel VT-x extensions to run virtual
5 * machines without emulation or binary translation.
6 *
7 * MMU support
8 *
9 * Copyright (C) 2006 Qumranet, Inc.
10 *
11 * Authors:
12 * Yaniv Kamay <yaniv@qumranet.com>
13 * Avi Kivity <avi@qumranet.com>
14 *
15 * This work is licensed under the terms of the GNU GPL, version 2. See
16 * the COPYING file in the top-level directory.
17 *
18 */
19
20 #include "vmx.h"
21 #include "mmu.h"
22
23 #include <linux/kvm_host.h>
24 #include <linux/types.h>
25 #include <linux/string.h>
26 #include <linux/mm.h>
27 #include <linux/highmem.h>
28 #include <linux/module.h>
29 #include <linux/swap.h>
30 #include <linux/hugetlb.h>
31 #include <linux/compiler.h>
32
33 #include <asm/page.h>
34 #include <asm/cmpxchg.h>
35 #include <asm/io.h>
36
37 /*
38 * When setting this variable to true it enables Two-Dimensional-Paging
39 * where the hardware walks 2 page tables:
40 * 1. the guest-virtual to guest-physical
41 * 2. while doing 1. it walks guest-physical to host-physical
42 * If the hardware supports that we don't need to do shadow paging.
43 */
44 bool tdp_enabled = false;
45
46 #undef MMU_DEBUG
47
48 #undef AUDIT
49
50 #ifdef AUDIT
51 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg);
52 #else
53 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg) {}
54 #endif
55
56 #ifdef MMU_DEBUG
57
58 #define pgprintk(x...) do { if (dbg) printk(x); } while (0)
59 #define rmap_printk(x...) do { if (dbg) printk(x); } while (0)
60
61 #else
62
63 #define pgprintk(x...) do { } while (0)
64 #define rmap_printk(x...) do { } while (0)
65
66 #endif
67
68 #if defined(MMU_DEBUG) || defined(AUDIT)
69 static int dbg = 1;
70 #endif
71
72 #ifndef MMU_DEBUG
73 #define ASSERT(x) do { } while (0)
74 #else
75 #define ASSERT(x) \
76 if (!(x)) { \
77 printk(KERN_WARNING "assertion failed %s:%d: %s\n", \
78 __FILE__, __LINE__, #x); \
79 }
80 #endif
81
82 #define PT_FIRST_AVAIL_BITS_SHIFT 9
83 #define PT64_SECOND_AVAIL_BITS_SHIFT 52
84
85 #define VALID_PAGE(x) ((x) != INVALID_PAGE)
86
87 #define PT64_LEVEL_BITS 9
88
89 #define PT64_LEVEL_SHIFT(level) \
90 (PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS)
91
92 #define PT64_LEVEL_MASK(level) \
93 (((1ULL << PT64_LEVEL_BITS) - 1) << PT64_LEVEL_SHIFT(level))
94
95 #define PT64_INDEX(address, level)\
96 (((address) >> PT64_LEVEL_SHIFT(level)) & ((1 << PT64_LEVEL_BITS) - 1))
97
98
99 #define PT32_LEVEL_BITS 10
100
101 #define PT32_LEVEL_SHIFT(level) \
102 (PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS)
103
104 #define PT32_LEVEL_MASK(level) \
105 (((1ULL << PT32_LEVEL_BITS) - 1) << PT32_LEVEL_SHIFT(level))
106
107 #define PT32_INDEX(address, level)\
108 (((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))
109
110
111 #define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))
112 #define PT64_DIR_BASE_ADDR_MASK \
113 (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))
114
115 #define PT32_BASE_ADDR_MASK PAGE_MASK
116 #define PT32_DIR_BASE_ADDR_MASK \
117 (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
118
119 #define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK \
120 | PT64_NX_MASK)
121
122 #define PFERR_PRESENT_MASK (1U << 0)
123 #define PFERR_WRITE_MASK (1U << 1)
124 #define PFERR_USER_MASK (1U << 2)
125 #define PFERR_FETCH_MASK (1U << 4)
126
127 #define PT_DIRECTORY_LEVEL 2
128 #define PT_PAGE_TABLE_LEVEL 1
129
130 #define RMAP_EXT 4
131
132 #define ACC_EXEC_MASK 1
133 #define ACC_WRITE_MASK PT_WRITABLE_MASK
134 #define ACC_USER_MASK PT_USER_MASK
135 #define ACC_ALL (ACC_EXEC_MASK | ACC_WRITE_MASK | ACC_USER_MASK)
136
137 struct kvm_pv_mmu_op_buffer {
138 void *ptr;
139 unsigned len;
140 unsigned processed;
141 char buf[512] __aligned(sizeof(long));
142 };
143
144 struct kvm_rmap_desc {
145 u64 *shadow_ptes[RMAP_EXT];
146 struct kvm_rmap_desc *more;
147 };
148
149 static struct kmem_cache *pte_chain_cache;
150 static struct kmem_cache *rmap_desc_cache;
151 static struct kmem_cache *mmu_page_header_cache;
152
153 static u64 __read_mostly shadow_trap_nonpresent_pte;
154 static u64 __read_mostly shadow_notrap_nonpresent_pte;
155 static u64 __read_mostly shadow_base_present_pte;
156 static u64 __read_mostly shadow_nx_mask;
157 static u64 __read_mostly shadow_x_mask; /* mutual exclusive with nx_mask */
158 static u64 __read_mostly shadow_user_mask;
159 static u64 __read_mostly shadow_accessed_mask;
160 static u64 __read_mostly shadow_dirty_mask;
161
162 void kvm_mmu_set_nonpresent_ptes(u64 trap_pte, u64 notrap_pte)
163 {
164 shadow_trap_nonpresent_pte = trap_pte;
165 shadow_notrap_nonpresent_pte = notrap_pte;
166 }
167 EXPORT_SYMBOL_GPL(kvm_mmu_set_nonpresent_ptes);
168
169 void kvm_mmu_set_base_ptes(u64 base_pte)
170 {
171 shadow_base_present_pte = base_pte;
172 }
173 EXPORT_SYMBOL_GPL(kvm_mmu_set_base_ptes);
174
175 void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
176 u64 dirty_mask, u64 nx_mask, u64 x_mask)
177 {
178 shadow_user_mask = user_mask;
179 shadow_accessed_mask = accessed_mask;
180 shadow_dirty_mask = dirty_mask;
181 shadow_nx_mask = nx_mask;
182 shadow_x_mask = x_mask;
183 }
184 EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);
185
186 static int is_write_protection(struct kvm_vcpu *vcpu)
187 {
188 return vcpu->arch.cr0 & X86_CR0_WP;
189 }
190
191 static int is_cpuid_PSE36(void)
192 {
193 return 1;
194 }
195
196 static int is_nx(struct kvm_vcpu *vcpu)
197 {
198 return vcpu->arch.shadow_efer & EFER_NX;
199 }
200
201 static int is_present_pte(unsigned long pte)
202 {
203 return pte & PT_PRESENT_MASK;
204 }
205
206 static int is_shadow_present_pte(u64 pte)
207 {
208 return pte != shadow_trap_nonpresent_pte
209 && pte != shadow_notrap_nonpresent_pte;
210 }
211
212 static int is_large_pte(u64 pte)
213 {
214 return pte & PT_PAGE_SIZE_MASK;
215 }
216
217 static int is_writeble_pte(unsigned long pte)
218 {
219 return pte & PT_WRITABLE_MASK;
220 }
221
222 static int is_dirty_pte(unsigned long pte)
223 {
224 return pte & shadow_dirty_mask;
225 }
226
227 static int is_rmap_pte(u64 pte)
228 {
229 return is_shadow_present_pte(pte);
230 }
231
232 static pfn_t spte_to_pfn(u64 pte)
233 {
234 return (pte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
235 }
236
237 static gfn_t pse36_gfn_delta(u32 gpte)
238 {
239 int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT;
240
241 return (gpte & PT32_DIR_PSE36_MASK) << shift;
242 }
243
244 static void set_shadow_pte(u64 *sptep, u64 spte)
245 {
246 #ifdef CONFIG_X86_64
247 set_64bit((unsigned long *)sptep, spte);
248 #else
249 set_64bit((unsigned long long *)sptep, spte);
250 #endif
251 }
252
253 static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
254 struct kmem_cache *base_cache, int min)
255 {
256 void *obj;
257
258 if (cache->nobjs >= min)
259 return 0;
260 while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
261 obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
262 if (!obj)
263 return -ENOMEM;
264 cache->objects[cache->nobjs++] = obj;
265 }
266 return 0;
267 }
268
269 static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
270 {
271 while (mc->nobjs)
272 kfree(mc->objects[--mc->nobjs]);
273 }
274
275 static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
276 int min)
277 {
278 struct page *page;
279
280 if (cache->nobjs >= min)
281 return 0;
282 while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
283 page = alloc_page(GFP_KERNEL);
284 if (!page)
285 return -ENOMEM;
286 set_page_private(page, 0);
287 cache->objects[cache->nobjs++] = page_address(page);
288 }
289 return 0;
290 }
291
292 static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
293 {
294 while (mc->nobjs)
295 free_page((unsigned long)mc->objects[--mc->nobjs]);
296 }
297
298 static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
299 {
300 int r;
301
302 r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_chain_cache,
303 pte_chain_cache, 4);
304 if (r)
305 goto out;
306 r = mmu_topup_memory_cache(&vcpu->arch.mmu_rmap_desc_cache,
307 rmap_desc_cache, 1);
308 if (r)
309 goto out;
310 r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
311 if (r)
312 goto out;
313 r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
314 mmu_page_header_cache, 4);
315 out:
316 return r;
317 }
318
319 static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
320 {
321 mmu_free_memory_cache(&vcpu->arch.mmu_pte_chain_cache);
322 mmu_free_memory_cache(&vcpu->arch.mmu_rmap_desc_cache);
323 mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache);
324 mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache);
325 }
326
327 static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc,
328 size_t size)
329 {
330 void *p;
331
332 BUG_ON(!mc->nobjs);
333 p = mc->objects[--mc->nobjs];
334 memset(p, 0, size);
335 return p;
336 }
337
338 static struct kvm_pte_chain *mmu_alloc_pte_chain(struct kvm_vcpu *vcpu)
339 {
340 return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_chain_cache,
341 sizeof(struct kvm_pte_chain));
342 }
343
344 static void mmu_free_pte_chain(struct kvm_pte_chain *pc)
345 {
346 kfree(pc);
347 }
348
349 static struct kvm_rmap_desc *mmu_alloc_rmap_desc(struct kvm_vcpu *vcpu)
350 {
351 return mmu_memory_cache_alloc(&vcpu->arch.mmu_rmap_desc_cache,
352 sizeof(struct kvm_rmap_desc));
353 }
354
355 static void mmu_free_rmap_desc(struct kvm_rmap_desc *rd)
356 {
357 kfree(rd);
358 }
359
360 /*
361 * Return the pointer to the largepage write count for a given
362 * gfn, handling slots that are not large page aligned.
363 */
364 static int *slot_largepage_idx(gfn_t gfn, struct kvm_memory_slot *slot)
365 {
366 unsigned long idx;
367
368 idx = (gfn / KVM_PAGES_PER_HPAGE) -
369 (slot->base_gfn / KVM_PAGES_PER_HPAGE);
370 return &slot->lpage_info[idx].write_count;
371 }
372
373 static void account_shadowed(struct kvm *kvm, gfn_t gfn)
374 {
375 int *write_count;
376
377 write_count = slot_largepage_idx(gfn, gfn_to_memslot(kvm, gfn));
378 *write_count += 1;
379 }
380
381 static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn)
382 {
383 int *write_count;
384
385 write_count = slot_largepage_idx(gfn, gfn_to_memslot(kvm, gfn));
386 *write_count -= 1;
387 WARN_ON(*write_count < 0);
388 }
389
390 static int has_wrprotected_page(struct kvm *kvm, gfn_t gfn)
391 {
392 struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
393 int *largepage_idx;
394
395 if (slot) {
396 largepage_idx = slot_largepage_idx(gfn, slot);
397 return *largepage_idx;
398 }
399
400 return 1;
401 }
402
403 static int host_largepage_backed(struct kvm *kvm, gfn_t gfn)
404 {
405 struct vm_area_struct *vma;
406 unsigned long addr;
407
408 addr = gfn_to_hva(kvm, gfn);
409 if (kvm_is_error_hva(addr))
410 return 0;
411
412 vma = find_vma(current->mm, addr);
413 if (vma && is_vm_hugetlb_page(vma))
414 return 1;
415
416 return 0;
417 }
418
419 static int is_largepage_backed(struct kvm_vcpu *vcpu, gfn_t large_gfn)
420 {
421 struct kvm_memory_slot *slot;
422
423 if (has_wrprotected_page(vcpu->kvm, large_gfn))
424 return 0;
425
426 if (!host_largepage_backed(vcpu->kvm, large_gfn))
427 return 0;
428
429 slot = gfn_to_memslot(vcpu->kvm, large_gfn);
430 if (slot && slot->dirty_bitmap)
431 return 0;
432
433 return 1;
434 }
435
436 /*
437 * Take gfn and return the reverse mapping to it.
438 * Note: gfn must be unaliased before this function get called
439 */
440
441 static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int lpage)
442 {
443 struct kvm_memory_slot *slot;
444 unsigned long idx;
445
446 slot = gfn_to_memslot(kvm, gfn);
447 if (!lpage)
448 return &slot->rmap[gfn - slot->base_gfn];
449
450 idx = (gfn / KVM_PAGES_PER_HPAGE) -
451 (slot->base_gfn / KVM_PAGES_PER_HPAGE);
452
453 return &slot->lpage_info[idx].rmap_pde;
454 }
455
456 /*
457 * Reverse mapping data structures:
458 *
459 * If rmapp bit zero is zero, then rmapp point to the shadw page table entry
460 * that points to page_address(page).
461 *
462 * If rmapp bit zero is one, (then rmap & ~1) points to a struct kvm_rmap_desc
463 * containing more mappings.
464 */
465 static void rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn, int lpage)
466 {
467 struct kvm_mmu_page *sp;
468 struct kvm_rmap_desc *desc;
469 unsigned long *rmapp;
470 int i;
471
472 if (!is_rmap_pte(*spte))
473 return;
474 gfn = unalias_gfn(vcpu->kvm, gfn);
475 sp = page_header(__pa(spte));
476 sp->gfns[spte - sp->spt] = gfn;
477 rmapp = gfn_to_rmap(vcpu->kvm, gfn, lpage);
478 if (!*rmapp) {
479 rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte);
480 *rmapp = (unsigned long)spte;
481 } else if (!(*rmapp & 1)) {
482 rmap_printk("rmap_add: %p %llx 1->many\n", spte, *spte);
483 desc = mmu_alloc_rmap_desc(vcpu);
484 desc->shadow_ptes[0] = (u64 *)*rmapp;
485 desc->shadow_ptes[1] = spte;
486 *rmapp = (unsigned long)desc | 1;
487 } else {
488 rmap_printk("rmap_add: %p %llx many->many\n", spte, *spte);
489 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
490 while (desc->shadow_ptes[RMAP_EXT-1] && desc->more)
491 desc = desc->more;
492 if (desc->shadow_ptes[RMAP_EXT-1]) {
493 desc->more = mmu_alloc_rmap_desc(vcpu);
494 desc = desc->more;
495 }
496 for (i = 0; desc->shadow_ptes[i]; ++i)
497 ;
498 desc->shadow_ptes[i] = spte;
499 }
500 }
501
502 static void rmap_desc_remove_entry(unsigned long *rmapp,
503 struct kvm_rmap_desc *desc,
504 int i,
505 struct kvm_rmap_desc *prev_desc)
506 {
507 int j;
508
509 for (j = RMAP_EXT - 1; !desc->shadow_ptes[j] && j > i; --j)
510 ;
511 desc->shadow_ptes[i] = desc->shadow_ptes[j];
512 desc->shadow_ptes[j] = NULL;
513 if (j != 0)
514 return;
515 if (!prev_desc && !desc->more)
516 *rmapp = (unsigned long)desc->shadow_ptes[0];
517 else
518 if (prev_desc)
519 prev_desc->more = desc->more;
520 else
521 *rmapp = (unsigned long)desc->more | 1;
522 mmu_free_rmap_desc(desc);
523 }
524
525 static void rmap_remove(struct kvm *kvm, u64 *spte)
526 {
527 struct kvm_rmap_desc *desc;
528 struct kvm_rmap_desc *prev_desc;
529 struct kvm_mmu_page *sp;
530 pfn_t pfn;
531 unsigned long *rmapp;
532 int i;
533
534 if (!is_rmap_pte(*spte))
535 return;
536 sp = page_header(__pa(spte));
537 pfn = spte_to_pfn(*spte);
538 if (*spte & shadow_accessed_mask)
539 kvm_set_pfn_accessed(pfn);
540 if (is_writeble_pte(*spte))
541 kvm_release_pfn_dirty(pfn);
542 else
543 kvm_release_pfn_clean(pfn);
544 rmapp = gfn_to_rmap(kvm, sp->gfns[spte - sp->spt], is_large_pte(*spte));
545 if (!*rmapp) {
546 printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte);
547 BUG();
548 } else if (!(*rmapp & 1)) {
549 rmap_printk("rmap_remove: %p %llx 1->0\n", spte, *spte);
550 if ((u64 *)*rmapp != spte) {
551 printk(KERN_ERR "rmap_remove: %p %llx 1->BUG\n",
552 spte, *spte);
553 BUG();
554 }
555 *rmapp = 0;
556 } else {
557 rmap_printk("rmap_remove: %p %llx many->many\n", spte, *spte);
558 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
559 prev_desc = NULL;
560 while (desc) {
561 for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i)
562 if (desc->shadow_ptes[i] == spte) {
563 rmap_desc_remove_entry(rmapp,
564 desc, i,
565 prev_desc);
566 return;
567 }
568 prev_desc = desc;
569 desc = desc->more;
570 }
571 BUG();
572 }
573 }
574
575 static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte)
576 {
577 struct kvm_rmap_desc *desc;
578 struct kvm_rmap_desc *prev_desc;
579 u64 *prev_spte;
580 int i;
581
582 if (!*rmapp)
583 return NULL;
584 else if (!(*rmapp & 1)) {
585 if (!spte)
586 return (u64 *)*rmapp;
587 return NULL;
588 }
589 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
590 prev_desc = NULL;
591 prev_spte = NULL;
592 while (desc) {
593 for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i) {
594 if (prev_spte == spte)
595 return desc->shadow_ptes[i];
596 prev_spte = desc->shadow_ptes[i];
597 }
598 desc = desc->more;
599 }
600 return NULL;
601 }
602
603 static void rmap_write_protect(struct kvm *kvm, u64 gfn)
604 {
605 unsigned long *rmapp;
606 u64 *spte;
607 int write_protected = 0;
608
609 gfn = unalias_gfn(kvm, gfn);
610 rmapp = gfn_to_rmap(kvm, gfn, 0);
611
612 spte = rmap_next(kvm, rmapp, NULL);
613 while (spte) {
614 BUG_ON(!spte);
615 BUG_ON(!(*spte & PT_PRESENT_MASK));
616 rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
617 if (is_writeble_pte(*spte)) {
618 set_shadow_pte(spte, *spte & ~PT_WRITABLE_MASK);
619 write_protected = 1;
620 }
621 spte = rmap_next(kvm, rmapp, spte);
622 }
623 if (write_protected) {
624 pfn_t pfn;
625
626 spte = rmap_next(kvm, rmapp, NULL);
627 pfn = spte_to_pfn(*spte);
628 kvm_set_pfn_dirty(pfn);
629 }
630
631 /* check for huge page mappings */
632 rmapp = gfn_to_rmap(kvm, gfn, 1);
633 spte = rmap_next(kvm, rmapp, NULL);
634 while (spte) {
635 BUG_ON(!spte);
636 BUG_ON(!(*spte & PT_PRESENT_MASK));
637 BUG_ON((*spte & (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK)) != (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK));
638 pgprintk("rmap_write_protect(large): spte %p %llx %lld\n", spte, *spte, gfn);
639 if (is_writeble_pte(*spte)) {
640 rmap_remove(kvm, spte);
641 --kvm->stat.lpages;
642 set_shadow_pte(spte, shadow_trap_nonpresent_pte);
643 spte = NULL;
644 write_protected = 1;
645 }
646 spte = rmap_next(kvm, rmapp, spte);
647 }
648
649 if (write_protected)
650 kvm_flush_remote_tlbs(kvm);
651
652 account_shadowed(kvm, gfn);
653 }
654
655 #ifdef MMU_DEBUG
656 static int is_empty_shadow_page(u64 *spt)
657 {
658 u64 *pos;
659 u64 *end;
660
661 for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
662 if (is_shadow_present_pte(*pos)) {
663 printk(KERN_ERR "%s: %p %llx\n", __func__,
664 pos, *pos);
665 return 0;
666 }
667 return 1;
668 }
669 #endif
670
671 static void kvm_mmu_free_page(struct kvm *kvm, struct kvm_mmu_page *sp)
672 {
673 ASSERT(is_empty_shadow_page(sp->spt));
674 list_del(&sp->link);
675 __free_page(virt_to_page(sp->spt));
676 __free_page(virt_to_page(sp->gfns));
677 kfree(sp);
678 ++kvm->arch.n_free_mmu_pages;
679 }
680
681 static unsigned kvm_page_table_hashfn(gfn_t gfn)
682 {
683 return gfn & ((1 << KVM_MMU_HASH_SHIFT) - 1);
684 }
685
686 static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
687 u64 *parent_pte)
688 {
689 struct kvm_mmu_page *sp;
690
691 sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache, sizeof *sp);
692 sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
693 sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
694 set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
695 list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
696 ASSERT(is_empty_shadow_page(sp->spt));
697 sp->slot_bitmap = 0;
698 sp->multimapped = 0;
699 sp->parent_pte = parent_pte;
700 --vcpu->kvm->arch.n_free_mmu_pages;
701 return sp;
702 }
703
704 static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
705 struct kvm_mmu_page *sp, u64 *parent_pte)
706 {
707 struct kvm_pte_chain *pte_chain;
708 struct hlist_node *node;
709 int i;
710
711 if (!parent_pte)
712 return;
713 if (!sp->multimapped) {
714 u64 *old = sp->parent_pte;
715
716 if (!old) {
717 sp->parent_pte = parent_pte;
718 return;
719 }
720 sp->multimapped = 1;
721 pte_chain = mmu_alloc_pte_chain(vcpu);
722 INIT_HLIST_HEAD(&sp->parent_ptes);
723 hlist_add_head(&pte_chain->link, &sp->parent_ptes);
724 pte_chain->parent_ptes[0] = old;
725 }
726 hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link) {
727 if (pte_chain->parent_ptes[NR_PTE_CHAIN_ENTRIES-1])
728 continue;
729 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i)
730 if (!pte_chain->parent_ptes[i]) {
731 pte_chain->parent_ptes[i] = parent_pte;
732 return;
733 }
734 }
735 pte_chain = mmu_alloc_pte_chain(vcpu);
736 BUG_ON(!pte_chain);
737 hlist_add_head(&pte_chain->link, &sp->parent_ptes);
738 pte_chain->parent_ptes[0] = parent_pte;
739 }
740
741 static void mmu_page_remove_parent_pte(struct kvm_mmu_page *sp,
742 u64 *parent_pte)
743 {
744 struct kvm_pte_chain *pte_chain;
745 struct hlist_node *node;
746 int i;
747
748 if (!sp->multimapped) {
749 BUG_ON(sp->parent_pte != parent_pte);
750 sp->parent_pte = NULL;
751 return;
752 }
753 hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
754 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
755 if (!pte_chain->parent_ptes[i])
756 break;
757 if (pte_chain->parent_ptes[i] != parent_pte)
758 continue;
759 while (i + 1 < NR_PTE_CHAIN_ENTRIES
760 && pte_chain->parent_ptes[i + 1]) {
761 pte_chain->parent_ptes[i]
762 = pte_chain->parent_ptes[i + 1];
763 ++i;
764 }
765 pte_chain->parent_ptes[i] = NULL;
766 if (i == 0) {
767 hlist_del(&pte_chain->link);
768 mmu_free_pte_chain(pte_chain);
769 if (hlist_empty(&sp->parent_ptes)) {
770 sp->multimapped = 0;
771 sp->parent_pte = NULL;
772 }
773 }
774 return;
775 }
776 BUG();
777 }
778
779 static void nonpaging_prefetch_page(struct kvm_vcpu *vcpu,
780 struct kvm_mmu_page *sp)
781 {
782 int i;
783
784 for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
785 sp->spt[i] = shadow_trap_nonpresent_pte;
786 }
787
788 static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm *kvm, gfn_t gfn)
789 {
790 unsigned index;
791 struct hlist_head *bucket;
792 struct kvm_mmu_page *sp;
793 struct hlist_node *node;
794
795 pgprintk("%s: looking for gfn %lx\n", __func__, gfn);
796 index = kvm_page_table_hashfn(gfn);
797 bucket = &kvm->arch.mmu_page_hash[index];
798 hlist_for_each_entry(sp, node, bucket, hash_link)
799 if (sp->gfn == gfn && !sp->role.metaphysical
800 && !sp->role.invalid) {
801 pgprintk("%s: found role %x\n",
802 __func__, sp->role.word);
803 return sp;
804 }
805 return NULL;
806 }
807
808 static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
809 gfn_t gfn,
810 gva_t gaddr,
811 unsigned level,
812 int metaphysical,
813 unsigned access,
814 u64 *parent_pte)
815 {
816 union kvm_mmu_page_role role;
817 unsigned index;
818 unsigned quadrant;
819 struct hlist_head *bucket;
820 struct kvm_mmu_page *sp;
821 struct hlist_node *node;
822
823 role.word = 0;
824 role.glevels = vcpu->arch.mmu.root_level;
825 role.level = level;
826 role.metaphysical = metaphysical;
827 role.access = access;
828 if (vcpu->arch.mmu.root_level <= PT32_ROOT_LEVEL) {
829 quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
830 quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
831 role.quadrant = quadrant;
832 }
833 pgprintk("%s: looking gfn %lx role %x\n", __func__,
834 gfn, role.word);
835 index = kvm_page_table_hashfn(gfn);
836 bucket = &vcpu->kvm->arch.mmu_page_hash[index];
837 hlist_for_each_entry(sp, node, bucket, hash_link)
838 if (sp->gfn == gfn && sp->role.word == role.word) {
839 mmu_page_add_parent_pte(vcpu, sp, parent_pte);
840 pgprintk("%s: found\n", __func__);
841 return sp;
842 }
843 ++vcpu->kvm->stat.mmu_cache_miss;
844 sp = kvm_mmu_alloc_page(vcpu, parent_pte);
845 if (!sp)
846 return sp;
847 pgprintk("%s: adding gfn %lx role %x\n", __func__, gfn, role.word);
848 sp->gfn = gfn;
849 sp->role = role;
850 hlist_add_head(&sp->hash_link, bucket);
851 if (!metaphysical)
852 rmap_write_protect(vcpu->kvm, gfn);
853 vcpu->arch.mmu.prefetch_page(vcpu, sp);
854 return sp;
855 }
856
857 static void kvm_mmu_page_unlink_children(struct kvm *kvm,
858 struct kvm_mmu_page *sp)
859 {
860 unsigned i;
861 u64 *pt;
862 u64 ent;
863
864 pt = sp->spt;
865
866 if (sp->role.level == PT_PAGE_TABLE_LEVEL) {
867 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
868 if (is_shadow_present_pte(pt[i]))
869 rmap_remove(kvm, &pt[i]);
870 pt[i] = shadow_trap_nonpresent_pte;
871 }
872 kvm_flush_remote_tlbs(kvm);
873 return;
874 }
875
876 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
877 ent = pt[i];
878
879 if (is_shadow_present_pte(ent)) {
880 if (!is_large_pte(ent)) {
881 ent &= PT64_BASE_ADDR_MASK;
882 mmu_page_remove_parent_pte(page_header(ent),
883 &pt[i]);
884 } else {
885 --kvm->stat.lpages;
886 rmap_remove(kvm, &pt[i]);
887 }
888 }
889 pt[i] = shadow_trap_nonpresent_pte;
890 }
891 kvm_flush_remote_tlbs(kvm);
892 }
893
894 static void kvm_mmu_put_page(struct kvm_mmu_page *sp, u64 *parent_pte)
895 {
896 mmu_page_remove_parent_pte(sp, parent_pte);
897 }
898
899 static void kvm_mmu_reset_last_pte_updated(struct kvm *kvm)
900 {
901 int i;
902
903 for (i = 0; i < KVM_MAX_VCPUS; ++i)
904 if (kvm->vcpus[i])
905 kvm->vcpus[i]->arch.last_pte_updated = NULL;
906 }
907
908 static void kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp)
909 {
910 u64 *parent_pte;
911
912 ++kvm->stat.mmu_shadow_zapped;
913 while (sp->multimapped || sp->parent_pte) {
914 if (!sp->multimapped)
915 parent_pte = sp->parent_pte;
916 else {
917 struct kvm_pte_chain *chain;
918
919 chain = container_of(sp->parent_ptes.first,
920 struct kvm_pte_chain, link);
921 parent_pte = chain->parent_ptes[0];
922 }
923 BUG_ON(!parent_pte);
924 kvm_mmu_put_page(sp, parent_pte);
925 set_shadow_pte(parent_pte, shadow_trap_nonpresent_pte);
926 }
927 kvm_mmu_page_unlink_children(kvm, sp);
928 if (!sp->root_count) {
929 if (!sp->role.metaphysical)
930 unaccount_shadowed(kvm, sp->gfn);
931 hlist_del(&sp->hash_link);
932 kvm_mmu_free_page(kvm, sp);
933 } else {
934 list_move(&sp->link, &kvm->arch.active_mmu_pages);
935 sp->role.invalid = 1;
936 kvm_reload_remote_mmus(kvm);
937 }
938 kvm_mmu_reset_last_pte_updated(kvm);
939 }
940
941 /*
942 * Changing the number of mmu pages allocated to the vm
943 * Note: if kvm_nr_mmu_pages is too small, you will get dead lock
944 */
945 void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages)
946 {
947 /*
948 * If we set the number of mmu pages to be smaller be than the
949 * number of actived pages , we must to free some mmu pages before we
950 * change the value
951 */
952
953 if ((kvm->arch.n_alloc_mmu_pages - kvm->arch.n_free_mmu_pages) >
954 kvm_nr_mmu_pages) {
955 int n_used_mmu_pages = kvm->arch.n_alloc_mmu_pages
956 - kvm->arch.n_free_mmu_pages;
957
958 while (n_used_mmu_pages > kvm_nr_mmu_pages) {
959 struct kvm_mmu_page *page;
960
961 page = container_of(kvm->arch.active_mmu_pages.prev,
962 struct kvm_mmu_page, link);
963 kvm_mmu_zap_page(kvm, page);
964 n_used_mmu_pages--;
965 }
966 kvm->arch.n_free_mmu_pages = 0;
967 }
968 else
969 kvm->arch.n_free_mmu_pages += kvm_nr_mmu_pages
970 - kvm->arch.n_alloc_mmu_pages;
971
972 kvm->arch.n_alloc_mmu_pages = kvm_nr_mmu_pages;
973 }
974
975 static int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
976 {
977 unsigned index;
978 struct hlist_head *bucket;
979 struct kvm_mmu_page *sp;
980 struct hlist_node *node, *n;
981 int r;
982
983 pgprintk("%s: looking for gfn %lx\n", __func__, gfn);
984 r = 0;
985 index = kvm_page_table_hashfn(gfn);
986 bucket = &kvm->arch.mmu_page_hash[index];
987 hlist_for_each_entry_safe(sp, node, n, bucket, hash_link)
988 if (sp->gfn == gfn && !sp->role.metaphysical) {
989 pgprintk("%s: gfn %lx role %x\n", __func__, gfn,
990 sp->role.word);
991 kvm_mmu_zap_page(kvm, sp);
992 r = 1;
993 }
994 return r;
995 }
996
997 static void mmu_unshadow(struct kvm *kvm, gfn_t gfn)
998 {
999 struct kvm_mmu_page *sp;
1000
1001 while ((sp = kvm_mmu_lookup_page(kvm, gfn)) != NULL) {
1002 pgprintk("%s: zap %lx %x\n", __func__, gfn, sp->role.word);
1003 kvm_mmu_zap_page(kvm, sp);
1004 }
1005 }
1006
1007 static void page_header_update_slot(struct kvm *kvm, void *pte, gfn_t gfn)
1008 {
1009 int slot = memslot_id(kvm, gfn_to_memslot(kvm, gfn));
1010 struct kvm_mmu_page *sp = page_header(__pa(pte));
1011
1012 __set_bit(slot, &sp->slot_bitmap);
1013 }
1014
1015 struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva)
1016 {
1017 struct page *page;
1018
1019 gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva);
1020
1021 if (gpa == UNMAPPED_GVA)
1022 return NULL;
1023
1024 down_read(&current->mm->mmap_sem);
1025 page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);
1026 up_read(&current->mm->mmap_sem);
1027
1028 return page;
1029 }
1030
1031 static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
1032 unsigned pt_access, unsigned pte_access,
1033 int user_fault, int write_fault, int dirty,
1034 int *ptwrite, int largepage, gfn_t gfn,
1035 pfn_t pfn, bool speculative)
1036 {
1037 u64 spte;
1038 int was_rmapped = 0;
1039 int was_writeble = is_writeble_pte(*shadow_pte);
1040
1041 pgprintk("%s: spte %llx access %x write_fault %d"
1042 " user_fault %d gfn %lx\n",
1043 __func__, *shadow_pte, pt_access,
1044 write_fault, user_fault, gfn);
1045
1046 if (is_rmap_pte(*shadow_pte)) {
1047 /*
1048 * If we overwrite a PTE page pointer with a 2MB PMD, unlink
1049 * the parent of the now unreachable PTE.
1050 */
1051 if (largepage && !is_large_pte(*shadow_pte)) {
1052 struct kvm_mmu_page *child;
1053 u64 pte = *shadow_pte;
1054
1055 child = page_header(pte & PT64_BASE_ADDR_MASK);
1056 mmu_page_remove_parent_pte(child, shadow_pte);
1057 } else if (pfn != spte_to_pfn(*shadow_pte)) {
1058 pgprintk("hfn old %lx new %lx\n",
1059 spte_to_pfn(*shadow_pte), pfn);
1060 rmap_remove(vcpu->kvm, shadow_pte);
1061 } else {
1062 if (largepage)
1063 was_rmapped = is_large_pte(*shadow_pte);
1064 else
1065 was_rmapped = 1;
1066 }
1067 }
1068
1069 /*
1070 * We don't set the accessed bit, since we sometimes want to see
1071 * whether the guest actually used the pte (in order to detect
1072 * demand paging).
1073 */
1074 spte = shadow_base_present_pte | shadow_dirty_mask;
1075 if (!speculative)
1076 pte_access |= PT_ACCESSED_MASK;
1077 if (!dirty)
1078 pte_access &= ~ACC_WRITE_MASK;
1079 if (pte_access & ACC_EXEC_MASK)
1080 spte |= shadow_x_mask;
1081 else
1082 spte |= shadow_nx_mask;
1083 if (pte_access & ACC_USER_MASK)
1084 spte |= shadow_user_mask;
1085 if (largepage)
1086 spte |= PT_PAGE_SIZE_MASK;
1087
1088 spte |= (u64)pfn << PAGE_SHIFT;
1089
1090 if ((pte_access & ACC_WRITE_MASK)
1091 || (write_fault && !is_write_protection(vcpu) && !user_fault)) {
1092 struct kvm_mmu_page *shadow;
1093
1094 spte |= PT_WRITABLE_MASK;
1095
1096 shadow = kvm_mmu_lookup_page(vcpu->kvm, gfn);
1097 if (shadow ||
1098 (largepage && has_wrprotected_page(vcpu->kvm, gfn))) {
1099 pgprintk("%s: found shadow page for %lx, marking ro\n",
1100 __func__, gfn);
1101 pte_access &= ~ACC_WRITE_MASK;
1102 if (is_writeble_pte(spte)) {
1103 spte &= ~PT_WRITABLE_MASK;
1104 kvm_x86_ops->tlb_flush(vcpu);
1105 }
1106 if (write_fault)
1107 *ptwrite = 1;
1108 }
1109 }
1110
1111 if (pte_access & ACC_WRITE_MASK)
1112 mark_page_dirty(vcpu->kvm, gfn);
1113
1114 pgprintk("%s: setting spte %llx\n", __func__, spte);
1115 pgprintk("instantiating %s PTE (%s) at %d (%llx) addr %llx\n",
1116 (spte&PT_PAGE_SIZE_MASK)? "2MB" : "4kB",
1117 (spte&PT_WRITABLE_MASK)?"RW":"R", gfn, spte, shadow_pte);
1118 set_shadow_pte(shadow_pte, spte);
1119 if (!was_rmapped && (spte & PT_PAGE_SIZE_MASK)
1120 && (spte & PT_PRESENT_MASK))
1121 ++vcpu->kvm->stat.lpages;
1122
1123 page_header_update_slot(vcpu->kvm, shadow_pte, gfn);
1124 if (!was_rmapped) {
1125 rmap_add(vcpu, shadow_pte, gfn, largepage);
1126 if (!is_rmap_pte(*shadow_pte))
1127 kvm_release_pfn_clean(pfn);
1128 } else {
1129 if (was_writeble)
1130 kvm_release_pfn_dirty(pfn);
1131 else
1132 kvm_release_pfn_clean(pfn);
1133 }
1134 if (speculative) {
1135 vcpu->arch.last_pte_updated = shadow_pte;
1136 vcpu->arch.last_pte_gfn = gfn;
1137 }
1138 }
1139
1140 static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
1141 {
1142 }
1143
1144 static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
1145 int largepage, gfn_t gfn, pfn_t pfn,
1146 int level)
1147 {
1148 hpa_t table_addr = vcpu->arch.mmu.root_hpa;
1149 int pt_write = 0;
1150
1151 for (; ; level--) {
1152 u32 index = PT64_INDEX(v, level);
1153 u64 *table;
1154
1155 ASSERT(VALID_PAGE(table_addr));
1156 table = __va(table_addr);
1157
1158 if (level == 1) {
1159 mmu_set_spte(vcpu, &table[index], ACC_ALL, ACC_ALL,
1160 0, write, 1, &pt_write, 0, gfn, pfn, false);
1161 return pt_write;
1162 }
1163
1164 if (largepage && level == 2) {
1165 mmu_set_spte(vcpu, &table[index], ACC_ALL, ACC_ALL,
1166 0, write, 1, &pt_write, 1, gfn, pfn, false);
1167 return pt_write;
1168 }
1169
1170 if (table[index] == shadow_trap_nonpresent_pte) {
1171 struct kvm_mmu_page *new_table;
1172 gfn_t pseudo_gfn;
1173
1174 pseudo_gfn = (v & PT64_DIR_BASE_ADDR_MASK)
1175 >> PAGE_SHIFT;
1176 new_table = kvm_mmu_get_page(vcpu, pseudo_gfn,
1177 v, level - 1,
1178 1, ACC_ALL, &table[index]);
1179 if (!new_table) {
1180 pgprintk("nonpaging_map: ENOMEM\n");
1181 kvm_release_pfn_clean(pfn);
1182 return -ENOMEM;
1183 }
1184
1185 table[index] = __pa(new_table->spt)
1186 | PT_PRESENT_MASK | PT_WRITABLE_MASK
1187 | shadow_user_mask | shadow_x_mask;
1188 }
1189 table_addr = table[index] & PT64_BASE_ADDR_MASK;
1190 }
1191 }
1192
1193 static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
1194 {
1195 int r;
1196 int largepage = 0;
1197 pfn_t pfn;
1198
1199 down_read(&current->mm->mmap_sem);
1200 if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
1201 gfn &= ~(KVM_PAGES_PER_HPAGE-1);
1202 largepage = 1;
1203 }
1204
1205 pfn = gfn_to_pfn(vcpu->kvm, gfn);
1206 up_read(&current->mm->mmap_sem);
1207
1208 /* mmio */
1209 if (is_error_pfn(pfn)) {
1210 kvm_release_pfn_clean(pfn);
1211 return 1;
1212 }
1213
1214 spin_lock(&vcpu->kvm->mmu_lock);
1215 kvm_mmu_free_some_pages(vcpu);
1216 r = __direct_map(vcpu, v, write, largepage, gfn, pfn,
1217 PT32E_ROOT_LEVEL);
1218 spin_unlock(&vcpu->kvm->mmu_lock);
1219
1220
1221 return r;
1222 }
1223
1224
1225 static void mmu_free_roots(struct kvm_vcpu *vcpu)
1226 {
1227 int i;
1228 struct kvm_mmu_page *sp;
1229
1230 if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
1231 return;
1232 spin_lock(&vcpu->kvm->mmu_lock);
1233 if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
1234 hpa_t root = vcpu->arch.mmu.root_hpa;
1235
1236 sp = page_header(root);
1237 --sp->root_count;
1238 if (!sp->root_count && sp->role.invalid)
1239 kvm_mmu_zap_page(vcpu->kvm, sp);
1240 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
1241 spin_unlock(&vcpu->kvm->mmu_lock);
1242 return;
1243 }
1244 for (i = 0; i < 4; ++i) {
1245 hpa_t root = vcpu->arch.mmu.pae_root[i];
1246
1247 if (root) {
1248 root &= PT64_BASE_ADDR_MASK;
1249 sp = page_header(root);
1250 --sp->root_count;
1251 if (!sp->root_count && sp->role.invalid)
1252 kvm_mmu_zap_page(vcpu->kvm, sp);
1253 }
1254 vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
1255 }
1256 spin_unlock(&vcpu->kvm->mmu_lock);
1257 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
1258 }
1259
1260 static void mmu_alloc_roots(struct kvm_vcpu *vcpu)
1261 {
1262 int i;
1263 gfn_t root_gfn;
1264 struct kvm_mmu_page *sp;
1265 int metaphysical = 0;
1266
1267 root_gfn = vcpu->arch.cr3 >> PAGE_SHIFT;
1268
1269 if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
1270 hpa_t root = vcpu->arch.mmu.root_hpa;
1271
1272 ASSERT(!VALID_PAGE(root));
1273 if (tdp_enabled)
1274 metaphysical = 1;
1275 sp = kvm_mmu_get_page(vcpu, root_gfn, 0,
1276 PT64_ROOT_LEVEL, metaphysical,
1277 ACC_ALL, NULL);
1278 root = __pa(sp->spt);
1279 ++sp->root_count;
1280 vcpu->arch.mmu.root_hpa = root;
1281 return;
1282 }
1283 metaphysical = !is_paging(vcpu);
1284 if (tdp_enabled)
1285 metaphysical = 1;
1286 for (i = 0; i < 4; ++i) {
1287 hpa_t root = vcpu->arch.mmu.pae_root[i];
1288
1289 ASSERT(!VALID_PAGE(root));
1290 if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
1291 if (!is_present_pte(vcpu->arch.pdptrs[i])) {
1292 vcpu->arch.mmu.pae_root[i] = 0;
1293 continue;
1294 }
1295 root_gfn = vcpu->arch.pdptrs[i] >> PAGE_SHIFT;
1296 } else if (vcpu->arch.mmu.root_level == 0)
1297 root_gfn = 0;
1298 sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
1299 PT32_ROOT_LEVEL, metaphysical,
1300 ACC_ALL, NULL);
1301 root = __pa(sp->spt);
1302 ++sp->root_count;
1303 vcpu->arch.mmu.pae_root[i] = root | PT_PRESENT_MASK;
1304 }
1305 vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
1306 }
1307
1308 static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr)
1309 {
1310 return vaddr;
1311 }
1312
1313 static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
1314 u32 error_code)
1315 {
1316 gfn_t gfn;
1317 int r;
1318
1319 pgprintk("%s: gva %lx error %x\n", __func__, gva, error_code);
1320 r = mmu_topup_memory_caches(vcpu);
1321 if (r)
1322 return r;
1323
1324 ASSERT(vcpu);
1325 ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
1326
1327 gfn = gva >> PAGE_SHIFT;
1328
1329 return nonpaging_map(vcpu, gva & PAGE_MASK,
1330 error_code & PFERR_WRITE_MASK, gfn);
1331 }
1332
1333 static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
1334 u32 error_code)
1335 {
1336 pfn_t pfn;
1337 int r;
1338 int largepage = 0;
1339 gfn_t gfn = gpa >> PAGE_SHIFT;
1340
1341 ASSERT(vcpu);
1342 ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
1343
1344 r = mmu_topup_memory_caches(vcpu);
1345 if (r)
1346 return r;
1347
1348 down_read(&current->mm->mmap_sem);
1349 if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
1350 gfn &= ~(KVM_PAGES_PER_HPAGE-1);
1351 largepage = 1;
1352 }
1353 pfn = gfn_to_pfn(vcpu->kvm, gfn);
1354 up_read(&current->mm->mmap_sem);
1355 if (is_error_pfn(pfn)) {
1356 kvm_release_pfn_clean(pfn);
1357 return 1;
1358 }
1359 spin_lock(&vcpu->kvm->mmu_lock);
1360 kvm_mmu_free_some_pages(vcpu);
1361 r = __direct_map(vcpu, gpa, error_code & PFERR_WRITE_MASK,
1362 largepage, gfn, pfn, kvm_x86_ops->get_tdp_level());
1363 spin_unlock(&vcpu->kvm->mmu_lock);
1364
1365 return r;
1366 }
1367
1368 static void nonpaging_free(struct kvm_vcpu *vcpu)
1369 {
1370 mmu_free_roots(vcpu);
1371 }
1372
1373 static int nonpaging_init_context(struct kvm_vcpu *vcpu)
1374 {
1375 struct kvm_mmu *context = &vcpu->arch.mmu;
1376
1377 context->new_cr3 = nonpaging_new_cr3;
1378 context->page_fault = nonpaging_page_fault;
1379 context->gva_to_gpa = nonpaging_gva_to_gpa;
1380 context->free = nonpaging_free;
1381 context->prefetch_page = nonpaging_prefetch_page;
1382 context->root_level = 0;
1383 context->shadow_root_level = PT32E_ROOT_LEVEL;
1384 context->root_hpa = INVALID_PAGE;
1385 return 0;
1386 }
1387
1388 void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
1389 {
1390 ++vcpu->stat.tlb_flush;
1391 kvm_x86_ops->tlb_flush(vcpu);
1392 }
1393
1394 static void paging_new_cr3(struct kvm_vcpu *vcpu)
1395 {
1396 pgprintk("%s: cr3 %lx\n", __func__, vcpu->arch.cr3);
1397 mmu_free_roots(vcpu);
1398 }
1399
1400 static void inject_page_fault(struct kvm_vcpu *vcpu,
1401 u64 addr,
1402 u32 err_code)
1403 {
1404 kvm_inject_page_fault(vcpu, addr, err_code);
1405 }
1406
1407 static void paging_free(struct kvm_vcpu *vcpu)
1408 {
1409 nonpaging_free(vcpu);
1410 }
1411
1412 #define PTTYPE 64
1413 #include "paging_tmpl.h"
1414 #undef PTTYPE
1415
1416 #define PTTYPE 32
1417 #include "paging_tmpl.h"
1418 #undef PTTYPE
1419
1420 static int paging64_init_context_common(struct kvm_vcpu *vcpu, int level)
1421 {
1422 struct kvm_mmu *context = &vcpu->arch.mmu;
1423
1424 ASSERT(is_pae(vcpu));
1425 context->new_cr3 = paging_new_cr3;
1426 context->page_fault = paging64_page_fault;
1427 context->gva_to_gpa = paging64_gva_to_gpa;
1428 context->prefetch_page = paging64_prefetch_page;
1429 context->free = paging_free;
1430 context->root_level = level;
1431 context->shadow_root_level = level;
1432 context->root_hpa = INVALID_PAGE;
1433 return 0;
1434 }
1435
1436 static int paging64_init_context(struct kvm_vcpu *vcpu)
1437 {
1438 return paging64_init_context_common(vcpu, PT64_ROOT_LEVEL);
1439 }
1440
1441 static int paging32_init_context(struct kvm_vcpu *vcpu)
1442 {
1443 struct kvm_mmu *context = &vcpu->arch.mmu;
1444
1445 context->new_cr3 = paging_new_cr3;
1446 context->page_fault = paging32_page_fault;
1447 context->gva_to_gpa = paging32_gva_to_gpa;
1448 context->free = paging_free;
1449 context->prefetch_page = paging32_prefetch_page;
1450 context->root_level = PT32_ROOT_LEVEL;
1451 context->shadow_root_level = PT32E_ROOT_LEVEL;
1452 context->root_hpa = INVALID_PAGE;
1453 return 0;
1454 }
1455
1456 static int paging32E_init_context(struct kvm_vcpu *vcpu)
1457 {
1458 return paging64_init_context_common(vcpu, PT32E_ROOT_LEVEL);
1459 }
1460
1461 static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
1462 {
1463 struct kvm_mmu *context = &vcpu->arch.mmu;
1464
1465 context->new_cr3 = nonpaging_new_cr3;
1466 context->page_fault = tdp_page_fault;
1467 context->free = nonpaging_free;
1468 context->prefetch_page = nonpaging_prefetch_page;
1469 context->shadow_root_level = kvm_x86_ops->get_tdp_level();
1470 context->root_hpa = INVALID_PAGE;
1471
1472 if (!is_paging(vcpu)) {
1473 context->gva_to_gpa = nonpaging_gva_to_gpa;
1474 context->root_level = 0;
1475 } else if (is_long_mode(vcpu)) {
1476 context->gva_to_gpa = paging64_gva_to_gpa;
1477 context->root_level = PT64_ROOT_LEVEL;
1478 } else if (is_pae(vcpu)) {
1479 context->gva_to_gpa = paging64_gva_to_gpa;
1480 context->root_level = PT32E_ROOT_LEVEL;
1481 } else {
1482 context->gva_to_gpa = paging32_gva_to_gpa;
1483 context->root_level = PT32_ROOT_LEVEL;
1484 }
1485
1486 return 0;
1487 }
1488
1489 static int init_kvm_softmmu(struct kvm_vcpu *vcpu)
1490 {
1491 ASSERT(vcpu);
1492 ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
1493
1494 if (!is_paging(vcpu))
1495 return nonpaging_init_context(vcpu);
1496 else if (is_long_mode(vcpu))
1497 return paging64_init_context(vcpu);
1498 else if (is_pae(vcpu))
1499 return paging32E_init_context(vcpu);
1500 else
1501 return paging32_init_context(vcpu);
1502 }
1503
1504 static int init_kvm_mmu(struct kvm_vcpu *vcpu)
1505 {
1506 vcpu->arch.update_pte.pfn = bad_pfn;
1507
1508 if (tdp_enabled)
1509 return init_kvm_tdp_mmu(vcpu);
1510 else
1511 return init_kvm_softmmu(vcpu);
1512 }
1513
1514 static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
1515 {
1516 ASSERT(vcpu);
1517 if (VALID_PAGE(vcpu->arch.mmu.root_hpa)) {
1518 vcpu->arch.mmu.free(vcpu);
1519 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
1520 }
1521 }
1522
1523 int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
1524 {
1525 destroy_kvm_mmu(vcpu);
1526 return init_kvm_mmu(vcpu);
1527 }
1528 EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
1529
1530 int kvm_mmu_load(struct kvm_vcpu *vcpu)
1531 {
1532 int r;
1533
1534 r = mmu_topup_memory_caches(vcpu);
1535 if (r)
1536 goto out;
1537 spin_lock(&vcpu->kvm->mmu_lock);
1538 kvm_mmu_free_some_pages(vcpu);
1539 mmu_alloc_roots(vcpu);
1540 spin_unlock(&vcpu->kvm->mmu_lock);
1541 kvm_x86_ops->set_cr3(vcpu, vcpu->arch.mmu.root_hpa);
1542 kvm_mmu_flush_tlb(vcpu);
1543 out:
1544 return r;
1545 }
1546 EXPORT_SYMBOL_GPL(kvm_mmu_load);
1547
1548 void kvm_mmu_unload(struct kvm_vcpu *vcpu)
1549 {
1550 mmu_free_roots(vcpu);
1551 }
1552
1553 static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
1554 struct kvm_mmu_page *sp,
1555 u64 *spte)
1556 {
1557 u64 pte;
1558 struct kvm_mmu_page *child;
1559
1560 pte = *spte;
1561 if (is_shadow_present_pte(pte)) {
1562 if (sp->role.level == PT_PAGE_TABLE_LEVEL ||
1563 is_large_pte(pte))
1564 rmap_remove(vcpu->kvm, spte);
1565 else {
1566 child = page_header(pte & PT64_BASE_ADDR_MASK);
1567 mmu_page_remove_parent_pte(child, spte);
1568 }
1569 }
1570 set_shadow_pte(spte, shadow_trap_nonpresent_pte);
1571 if (is_large_pte(pte))
1572 --vcpu->kvm->stat.lpages;
1573 }
1574
1575 static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
1576 struct kvm_mmu_page *sp,
1577 u64 *spte,
1578 const void *new)
1579 {
1580 if (sp->role.level != PT_PAGE_TABLE_LEVEL) {
1581 if (!vcpu->arch.update_pte.largepage ||
1582 sp->role.glevels == PT32_ROOT_LEVEL) {
1583 ++vcpu->kvm->stat.mmu_pde_zapped;
1584 return;
1585 }
1586 }
1587
1588 ++vcpu->kvm->stat.mmu_pte_updated;
1589 if (sp->role.glevels == PT32_ROOT_LEVEL)
1590 paging32_update_pte(vcpu, sp, spte, new);
1591 else
1592 paging64_update_pte(vcpu, sp, spte, new);
1593 }
1594
1595 static bool need_remote_flush(u64 old, u64 new)
1596 {
1597 if (!is_shadow_present_pte(old))
1598 return false;
1599 if (!is_shadow_present_pte(new))
1600 return true;
1601 if ((old ^ new) & PT64_BASE_ADDR_MASK)
1602 return true;
1603 old ^= PT64_NX_MASK;
1604 new ^= PT64_NX_MASK;
1605 return (old & ~new & PT64_PERM_MASK) != 0;
1606 }
1607
1608 static void mmu_pte_write_flush_tlb(struct kvm_vcpu *vcpu, u64 old, u64 new)
1609 {
1610 if (need_remote_flush(old, new))
1611 kvm_flush_remote_tlbs(vcpu->kvm);
1612 else
1613 kvm_mmu_flush_tlb(vcpu);
1614 }
1615
1616 static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu)
1617 {
1618 u64 *spte = vcpu->arch.last_pte_updated;
1619
1620 return !!(spte && (*spte & shadow_accessed_mask));
1621 }
1622
1623 static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
1624 const u8 *new, int bytes)
1625 {
1626 gfn_t gfn;
1627 int r;
1628 u64 gpte = 0;
1629 pfn_t pfn;
1630
1631 vcpu->arch.update_pte.largepage = 0;
1632
1633 if (bytes != 4 && bytes != 8)
1634 return;
1635
1636 /*
1637 * Assume that the pte write on a page table of the same type
1638 * as the current vcpu paging mode. This is nearly always true
1639 * (might be false while changing modes). Note it is verified later
1640 * by update_pte().
1641 */
1642 if (is_pae(vcpu)) {
1643 /* Handle a 32-bit guest writing two halves of a 64-bit gpte */
1644 if ((bytes == 4) && (gpa % 4 == 0)) {
1645 r = kvm_read_guest(vcpu->kvm, gpa & ~(u64)7, &gpte, 8);
1646 if (r)
1647 return;
1648 memcpy((void *)&gpte + (gpa % 8), new, 4);
1649 } else if ((bytes == 8) && (gpa % 8 == 0)) {
1650 memcpy((void *)&gpte, new, 8);
1651 }
1652 } else {
1653 if ((bytes == 4) && (gpa % 4 == 0))
1654 memcpy((void *)&gpte, new, 4);
1655 }
1656 if (!is_present_pte(gpte))
1657 return;
1658 gfn = (gpte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
1659
1660 down_read(&current->mm->mmap_sem);
1661 if (is_large_pte(gpte) && is_largepage_backed(vcpu, gfn)) {
1662 gfn &= ~(KVM_PAGES_PER_HPAGE-1);
1663 vcpu->arch.update_pte.largepage = 1;
1664 }
1665 pfn = gfn_to_pfn(vcpu->kvm, gfn);
1666 up_read(&current->mm->mmap_sem);
1667
1668 if (is_error_pfn(pfn)) {
1669 kvm_release_pfn_clean(pfn);
1670 return;
1671 }
1672 vcpu->arch.update_pte.gfn = gfn;
1673 vcpu->arch.update_pte.pfn = pfn;
1674 }
1675
1676 static void kvm_mmu_access_page(struct kvm_vcpu *vcpu, gfn_t gfn)
1677 {
1678 u64 *spte = vcpu->arch.last_pte_updated;
1679
1680 if (spte
1681 && vcpu->arch.last_pte_gfn == gfn
1682 && shadow_accessed_mask
1683 && !(*spte & shadow_accessed_mask)
1684 && is_shadow_present_pte(*spte))
1685 set_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte);
1686 }
1687
1688 void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
1689 const u8 *new, int bytes)
1690 {
1691 gfn_t gfn = gpa >> PAGE_SHIFT;
1692 struct kvm_mmu_page *sp;
1693 struct hlist_node *node, *n;
1694 struct hlist_head *bucket;
1695 unsigned index;
1696 u64 entry, gentry;
1697 u64 *spte;
1698 unsigned offset = offset_in_page(gpa);
1699 unsigned pte_size;
1700 unsigned page_offset;
1701 unsigned misaligned;
1702 unsigned quadrant;
1703 int level;
1704 int flooded = 0;
1705 int npte;
1706 int r;
1707
1708 pgprintk("%s: gpa %llx bytes %d\n", __func__, gpa, bytes);
1709 mmu_guess_page_from_pte_write(vcpu, gpa, new, bytes);
1710 spin_lock(&vcpu->kvm->mmu_lock);
1711 kvm_mmu_access_page(vcpu, gfn);
1712 kvm_mmu_free_some_pages(vcpu);
1713 ++vcpu->kvm->stat.mmu_pte_write;
1714 kvm_mmu_audit(vcpu, "pre pte write");
1715 if (gfn == vcpu->arch.last_pt_write_gfn
1716 && !last_updated_pte_accessed(vcpu)) {
1717 ++vcpu->arch.last_pt_write_count;
1718 if (vcpu->arch.last_pt_write_count >= 3)
1719 flooded = 1;
1720 } else {
1721 vcpu->arch.last_pt_write_gfn = gfn;
1722 vcpu->arch.last_pt_write_count = 1;
1723 vcpu->arch.last_pte_updated = NULL;
1724 }
1725 index = kvm_page_table_hashfn(gfn);
1726 bucket = &vcpu->kvm->arch.mmu_page_hash[index];
1727 hlist_for_each_entry_safe(sp, node, n, bucket, hash_link) {
1728 if (sp->gfn != gfn || sp->role.metaphysical)
1729 continue;
1730 pte_size = sp->role.glevels == PT32_ROOT_LEVEL ? 4 : 8;
1731 misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
1732 misaligned |= bytes < 4;
1733 if (misaligned || flooded) {
1734 /*
1735 * Misaligned accesses are too much trouble to fix
1736 * up; also, they usually indicate a page is not used
1737 * as a page table.
1738 *
1739 * If we're seeing too many writes to a page,
1740 * it may no longer be a page table, or we may be
1741 * forking, in which case it is better to unmap the
1742 * page.
1743 */
1744 pgprintk("misaligned: gpa %llx bytes %d role %x\n",
1745 gpa, bytes, sp->role.word);
1746 kvm_mmu_zap_page(vcpu->kvm, sp);
1747 ++vcpu->kvm->stat.mmu_flooded;
1748 continue;
1749 }
1750 page_offset = offset;
1751 level = sp->role.level;
1752 npte = 1;
1753 if (sp->role.glevels == PT32_ROOT_LEVEL) {
1754 page_offset <<= 1; /* 32->64 */
1755 /*
1756 * A 32-bit pde maps 4MB while the shadow pdes map
1757 * only 2MB. So we need to double the offset again
1758 * and zap two pdes instead of one.
1759 */
1760 if (level == PT32_ROOT_LEVEL) {
1761 page_offset &= ~7; /* kill rounding error */
1762 page_offset <<= 1;
1763 npte = 2;
1764 }
1765 quadrant = page_offset >> PAGE_SHIFT;
1766 page_offset &= ~PAGE_MASK;
1767 if (quadrant != sp->role.quadrant)
1768 continue;
1769 }
1770 spte = &sp->spt[page_offset / sizeof(*spte)];
1771 if ((gpa & (pte_size - 1)) || (bytes < pte_size)) {
1772 gentry = 0;
1773 r = kvm_read_guest_atomic(vcpu->kvm,
1774 gpa & ~(u64)(pte_size - 1),
1775 &gentry, pte_size);
1776 new = (const void *)&gentry;
1777 if (r < 0)
1778 new = NULL;
1779 }
1780 while (npte--) {
1781 entry = *spte;
1782 mmu_pte_write_zap_pte(vcpu, sp, spte);
1783 if (new)
1784 mmu_pte_write_new_pte(vcpu, sp, spte, new);
1785 mmu_pte_write_flush_tlb(vcpu, entry, *spte);
1786 ++spte;
1787 }
1788 }
1789 kvm_mmu_audit(vcpu, "post pte write");
1790 spin_unlock(&vcpu->kvm->mmu_lock);
1791 if (!is_error_pfn(vcpu->arch.update_pte.pfn)) {
1792 kvm_release_pfn_clean(vcpu->arch.update_pte.pfn);
1793 vcpu->arch.update_pte.pfn = bad_pfn;
1794 }
1795 }
1796
1797 int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
1798 {
1799 gpa_t gpa;
1800 int r;
1801
1802 gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva);
1803
1804 spin_lock(&vcpu->kvm->mmu_lock);
1805 r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
1806 spin_unlock(&vcpu->kvm->mmu_lock);
1807 return r;
1808 }
1809
1810 void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
1811 {
1812 while (vcpu->kvm->arch.n_free_mmu_pages < KVM_REFILL_PAGES) {
1813 struct kvm_mmu_page *sp;
1814
1815 sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev,
1816 struct kvm_mmu_page, link);
1817 kvm_mmu_zap_page(vcpu->kvm, sp);
1818 ++vcpu->kvm->stat.mmu_recycled;
1819 }
1820 }
1821
1822 int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code)
1823 {
1824 int r;
1825 enum emulation_result er;
1826
1827 r = vcpu->arch.mmu.page_fault(vcpu, cr2, error_code);
1828 if (r < 0)
1829 goto out;
1830
1831 if (!r) {
1832 r = 1;
1833 goto out;
1834 }
1835
1836 r = mmu_topup_memory_caches(vcpu);
1837 if (r)
1838 goto out;
1839
1840 er = emulate_instruction(vcpu, vcpu->run, cr2, error_code, 0);
1841
1842 switch (er) {
1843 case EMULATE_DONE:
1844 return 1;
1845 case EMULATE_DO_MMIO:
1846 ++vcpu->stat.mmio_exits;
1847 return 0;
1848 case EMULATE_FAIL:
1849 kvm_report_emulation_failure(vcpu, "pagetable");
1850 return 1;
1851 default:
1852 BUG();
1853 }
1854 out:
1855 return r;
1856 }
1857 EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);
1858
1859 void kvm_enable_tdp(void)
1860 {
1861 tdp_enabled = true;
1862 }
1863 EXPORT_SYMBOL_GPL(kvm_enable_tdp);
1864
1865 static void free_mmu_pages(struct kvm_vcpu *vcpu)
1866 {
1867 struct kvm_mmu_page *sp;
1868
1869 while (!list_empty(&vcpu->kvm->arch.active_mmu_pages)) {
1870 sp = container_of(vcpu->kvm->arch.active_mmu_pages.next,
1871 struct kvm_mmu_page, link);
1872 kvm_mmu_zap_page(vcpu->kvm, sp);
1873 cond_resched();
1874 }
1875 free_page((unsigned long)vcpu->arch.mmu.pae_root);
1876 }
1877
1878 static int alloc_mmu_pages(struct kvm_vcpu *vcpu)
1879 {
1880 struct page *page;
1881 int i;
1882
1883 ASSERT(vcpu);
1884
1885 if (vcpu->kvm->arch.n_requested_mmu_pages)
1886 vcpu->kvm->arch.n_free_mmu_pages =
1887 vcpu->kvm->arch.n_requested_mmu_pages;
1888 else
1889 vcpu->kvm->arch.n_free_mmu_pages =
1890 vcpu->kvm->arch.n_alloc_mmu_pages;
1891 /*
1892 * When emulating 32-bit mode, cr3 is only 32 bits even on x86_64.
1893 * Therefore we need to allocate shadow page tables in the first
1894 * 4GB of memory, which happens to fit the DMA32 zone.
1895 */
1896 page = alloc_page(GFP_KERNEL | __GFP_DMA32);
1897 if (!page)
1898 goto error_1;
1899 vcpu->arch.mmu.pae_root = page_address(page);
1900 for (i = 0; i < 4; ++i)
1901 vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
1902
1903 return 0;
1904
1905 error_1:
1906 free_mmu_pages(vcpu);
1907 return -ENOMEM;
1908 }
1909
1910 int kvm_mmu_create(struct kvm_vcpu *vcpu)
1911 {
1912 ASSERT(vcpu);
1913 ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
1914
1915 return alloc_mmu_pages(vcpu);
1916 }
1917
1918 int kvm_mmu_setup(struct kvm_vcpu *vcpu)
1919 {
1920 ASSERT(vcpu);
1921 ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
1922
1923 return init_kvm_mmu(vcpu);
1924 }
1925
1926 void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
1927 {
1928 ASSERT(vcpu);
1929
1930 destroy_kvm_mmu(vcpu);
1931 free_mmu_pages(vcpu);
1932 mmu_free_memory_caches(vcpu);
1933 }
1934
1935 void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
1936 {
1937 struct kvm_mmu_page *sp;
1938
1939 list_for_each_entry(sp, &kvm->arch.active_mmu_pages, link) {
1940 int i;
1941 u64 *pt;
1942
1943 if (!test_bit(slot, &sp->slot_bitmap))
1944 continue;
1945
1946 pt = sp->spt;
1947 for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
1948 /* avoid RMW */
1949 if (pt[i] & PT_WRITABLE_MASK)
1950 pt[i] &= ~PT_WRITABLE_MASK;
1951 }
1952 }
1953
1954 void kvm_mmu_zap_all(struct kvm *kvm)
1955 {
1956 struct kvm_mmu_page *sp, *node;
1957
1958 spin_lock(&kvm->mmu_lock);
1959 list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link)
1960 kvm_mmu_zap_page(kvm, sp);
1961 spin_unlock(&kvm->mmu_lock);
1962
1963 kvm_flush_remote_tlbs(kvm);
1964 }
1965
1966 static void kvm_mmu_remove_one_alloc_mmu_page(struct kvm *kvm)
1967 {
1968 struct kvm_mmu_page *page;
1969
1970 page = container_of(kvm->arch.active_mmu_pages.prev,
1971 struct kvm_mmu_page, link);
1972 kvm_mmu_zap_page(kvm, page);
1973 }
1974
1975 static int mmu_shrink(int nr_to_scan, gfp_t gfp_mask)
1976 {
1977 struct kvm *kvm;
1978 struct kvm *kvm_freed = NULL;
1979 int cache_count = 0;
1980
1981 spin_lock(&kvm_lock);
1982
1983 list_for_each_entry(kvm, &vm_list, vm_list) {
1984 int npages;
1985
1986 spin_lock(&kvm->mmu_lock);
1987 npages = kvm->arch.n_alloc_mmu_pages -
1988 kvm->arch.n_free_mmu_pages;
1989 cache_count += npages;
1990 if (!kvm_freed && nr_to_scan > 0 && npages > 0) {
1991 kvm_mmu_remove_one_alloc_mmu_page(kvm);
1992 cache_count--;
1993 kvm_freed = kvm;
1994 }
1995 nr_to_scan--;
1996
1997 spin_unlock(&kvm->mmu_lock);
1998 }
1999 if (kvm_freed)
2000 list_move_tail(&kvm_freed->vm_list, &vm_list);
2001
2002 spin_unlock(&kvm_lock);
2003
2004 return cache_count;
2005 }
2006
2007 static struct shrinker mmu_shrinker = {
2008 .shrink = mmu_shrink,
2009 .seeks = DEFAULT_SEEKS * 10,
2010 };
2011
2012 static void mmu_destroy_caches(void)
2013 {
2014 if (pte_chain_cache)
2015 kmem_cache_destroy(pte_chain_cache);
2016 if (rmap_desc_cache)
2017 kmem_cache_destroy(rmap_desc_cache);
2018 if (mmu_page_header_cache)
2019 kmem_cache_destroy(mmu_page_header_cache);
2020 }
2021
2022 void kvm_mmu_module_exit(void)
2023 {
2024 mmu_destroy_caches();
2025 unregister_shrinker(&mmu_shrinker);
2026 }
2027
2028 int kvm_mmu_module_init(void)
2029 {
2030 pte_chain_cache = kmem_cache_create("kvm_pte_chain",
2031 sizeof(struct kvm_pte_chain),
2032 0, 0, NULL);
2033 if (!pte_chain_cache)
2034 goto nomem;
2035 rmap_desc_cache = kmem_cache_create("kvm_rmap_desc",
2036 sizeof(struct kvm_rmap_desc),
2037 0, 0, NULL);
2038 if (!rmap_desc_cache)
2039 goto nomem;
2040
2041 mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
2042 sizeof(struct kvm_mmu_page),
2043 0, 0, NULL);
2044 if (!mmu_page_header_cache)
2045 goto nomem;
2046
2047 register_shrinker(&mmu_shrinker);
2048
2049 return 0;
2050
2051 nomem:
2052 mmu_destroy_caches();
2053 return -ENOMEM;
2054 }
2055
2056 /*
2057 * Caculate mmu pages needed for kvm.
2058 */
2059 unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
2060 {
2061 int i;
2062 unsigned int nr_mmu_pages;
2063 unsigned int nr_pages = 0;
2064
2065 for (i = 0; i < kvm->nmemslots; i++)
2066 nr_pages += kvm->memslots[i].npages;
2067
2068 nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000;
2069 nr_mmu_pages = max(nr_mmu_pages,
2070 (unsigned int) KVM_MIN_ALLOC_MMU_PAGES);
2071
2072 return nr_mmu_pages;
2073 }
2074
2075 static void *pv_mmu_peek_buffer(struct kvm_pv_mmu_op_buffer *buffer,
2076 unsigned len)
2077 {
2078 if (len > buffer->len)
2079 return NULL;
2080 return buffer->ptr;
2081 }
2082
2083 static void *pv_mmu_read_buffer(struct kvm_pv_mmu_op_buffer *buffer,
2084 unsigned len)
2085 {
2086 void *ret;
2087
2088 ret = pv_mmu_peek_buffer(buffer, len);
2089 if (!ret)
2090 return ret;
2091 buffer->ptr += len;
2092 buffer->len -= len;
2093 buffer->processed += len;
2094 return ret;
2095 }
2096
2097 static int kvm_pv_mmu_write(struct kvm_vcpu *vcpu,
2098 gpa_t addr, gpa_t value)
2099 {
2100 int bytes = 8;
2101 int r;
2102
2103 if (!is_long_mode(vcpu) && !is_pae(vcpu))
2104 bytes = 4;
2105
2106 r = mmu_topup_memory_caches(vcpu);
2107 if (r)
2108 return r;
2109
2110 if (!emulator_write_phys(vcpu, addr, &value, bytes))
2111 return -EFAULT;
2112
2113 return 1;
2114 }
2115
2116 static int kvm_pv_mmu_flush_tlb(struct kvm_vcpu *vcpu)
2117 {
2118 kvm_x86_ops->tlb_flush(vcpu);
2119 return 1;
2120 }
2121
2122 static int kvm_pv_mmu_release_pt(struct kvm_vcpu *vcpu, gpa_t addr)
2123 {
2124 spin_lock(&vcpu->kvm->mmu_lock);
2125 mmu_unshadow(vcpu->kvm, addr >> PAGE_SHIFT);
2126 spin_unlock(&vcpu->kvm->mmu_lock);
2127 return 1;
2128 }
2129
2130 static int kvm_pv_mmu_op_one(struct kvm_vcpu *vcpu,
2131 struct kvm_pv_mmu_op_buffer *buffer)
2132 {
2133 struct kvm_mmu_op_header *header;
2134
2135 header = pv_mmu_peek_buffer(buffer, sizeof *header);
2136 if (!header)
2137 return 0;
2138 switch (header->op) {
2139 case KVM_MMU_OP_WRITE_PTE: {
2140 struct kvm_mmu_op_write_pte *wpte;
2141
2142 wpte = pv_mmu_read_buffer(buffer, sizeof *wpte);
2143 if (!wpte)
2144 return 0;
2145 return kvm_pv_mmu_write(vcpu, wpte->pte_phys,
2146 wpte->pte_val);
2147 }
2148 case KVM_MMU_OP_FLUSH_TLB: {
2149 struct kvm_mmu_op_flush_tlb *ftlb;
2150
2151 ftlb = pv_mmu_read_buffer(buffer, sizeof *ftlb);
2152 if (!ftlb)
2153 return 0;
2154 return kvm_pv_mmu_flush_tlb(vcpu);
2155 }
2156 case KVM_MMU_OP_RELEASE_PT: {
2157 struct kvm_mmu_op_release_pt *rpt;
2158
2159 rpt = pv_mmu_read_buffer(buffer, sizeof *rpt);
2160 if (!rpt)
2161 return 0;
2162 return kvm_pv_mmu_release_pt(vcpu, rpt->pt_phys);
2163 }
2164 default: return 0;
2165 }
2166 }
2167
2168 int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes,
2169 gpa_t addr, unsigned long *ret)
2170 {
2171 int r;
2172 struct kvm_pv_mmu_op_buffer buffer;
2173
2174 buffer.ptr = buffer.buf;
2175 buffer.len = min_t(unsigned long, bytes, sizeof buffer.buf);
2176 buffer.processed = 0;
2177
2178 r = kvm_read_guest(vcpu->kvm, addr, buffer.buf, buffer.len);
2179 if (r)
2180 goto out;
2181
2182 while (buffer.len) {
2183 r = kvm_pv_mmu_op_one(vcpu, &buffer);
2184 if (r < 0)
2185 goto out;
2186 if (r == 0)
2187 break;
2188 }
2189
2190 r = 1;
2191 out:
2192 *ret = buffer.processed;
2193 return r;
2194 }
2195
2196 #ifdef AUDIT
2197
2198 static const char *audit_msg;
2199
2200 static gva_t canonicalize(gva_t gva)
2201 {
2202 #ifdef CONFIG_X86_64
2203 gva = (long long)(gva << 16) >> 16;
2204 #endif
2205 return gva;
2206 }
2207
2208 static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
2209 gva_t va, int level)
2210 {
2211 u64 *pt = __va(page_pte & PT64_BASE_ADDR_MASK);
2212 int i;
2213 gva_t va_delta = 1ul << (PAGE_SHIFT + 9 * (level - 1));
2214
2215 for (i = 0; i < PT64_ENT_PER_PAGE; ++i, va += va_delta) {
2216 u64 ent = pt[i];
2217
2218 if (ent == shadow_trap_nonpresent_pte)
2219 continue;
2220
2221 va = canonicalize(va);
2222 if (level > 1) {
2223 if (ent == shadow_notrap_nonpresent_pte)
2224 printk(KERN_ERR "audit: (%s) nontrapping pte"
2225 " in nonleaf level: levels %d gva %lx"
2226 " level %d pte %llx\n", audit_msg,
2227 vcpu->arch.mmu.root_level, va, level, ent);
2228
2229 audit_mappings_page(vcpu, ent, va, level - 1);
2230 } else {
2231 gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, va);
2232 hpa_t hpa = (hpa_t)gpa_to_pfn(vcpu, gpa) << PAGE_SHIFT;
2233
2234 if (is_shadow_present_pte(ent)
2235 && (ent & PT64_BASE_ADDR_MASK) != hpa)
2236 printk(KERN_ERR "xx audit error: (%s) levels %d"
2237 " gva %lx gpa %llx hpa %llx ent %llx %d\n",
2238 audit_msg, vcpu->arch.mmu.root_level,
2239 va, gpa, hpa, ent,
2240 is_shadow_present_pte(ent));
2241 else if (ent == shadow_notrap_nonpresent_pte
2242 && !is_error_hpa(hpa))
2243 printk(KERN_ERR "audit: (%s) notrap shadow,"
2244 " valid guest gva %lx\n", audit_msg, va);
2245 kvm_release_pfn_clean(pfn);
2246
2247 }
2248 }
2249 }
2250
2251 static void audit_mappings(struct kvm_vcpu *vcpu)
2252 {
2253 unsigned i;
2254
2255 if (vcpu->arch.mmu.root_level == 4)
2256 audit_mappings_page(vcpu, vcpu->arch.mmu.root_hpa, 0, 4);
2257 else
2258 for (i = 0; i < 4; ++i)
2259 if (vcpu->arch.mmu.pae_root[i] & PT_PRESENT_MASK)
2260 audit_mappings_page(vcpu,
2261 vcpu->arch.mmu.pae_root[i],
2262 i << 30,
2263 2);
2264 }
2265
2266 static int count_rmaps(struct kvm_vcpu *vcpu)
2267 {
2268 int nmaps = 0;
2269 int i, j, k;
2270
2271 for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
2272 struct kvm_memory_slot *m = &vcpu->kvm->memslots[i];
2273 struct kvm_rmap_desc *d;
2274
2275 for (j = 0; j < m->npages; ++j) {
2276 unsigned long *rmapp = &m->rmap[j];
2277
2278 if (!*rmapp)
2279 continue;
2280 if (!(*rmapp & 1)) {
2281 ++nmaps;
2282 continue;
2283 }
2284 d = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
2285 while (d) {
2286 for (k = 0; k < RMAP_EXT; ++k)
2287 if (d->shadow_ptes[k])
2288 ++nmaps;
2289 else
2290 break;
2291 d = d->more;
2292 }
2293 }
2294 }
2295 return nmaps;
2296 }
2297
2298 static int count_writable_mappings(struct kvm_vcpu *vcpu)
2299 {
2300 int nmaps = 0;
2301 struct kvm_mmu_page *sp;
2302 int i;
2303
2304 list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
2305 u64 *pt = sp->spt;
2306
2307 if (sp->role.level != PT_PAGE_TABLE_LEVEL)
2308 continue;
2309
2310 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
2311 u64 ent = pt[i];
2312
2313 if (!(ent & PT_PRESENT_MASK))
2314 continue;
2315 if (!(ent & PT_WRITABLE_MASK))
2316 continue;
2317 ++nmaps;
2318 }
2319 }
2320 return nmaps;
2321 }
2322
2323 static void audit_rmap(struct kvm_vcpu *vcpu)
2324 {
2325 int n_rmap = count_rmaps(vcpu);
2326 int n_actual = count_writable_mappings(vcpu);
2327
2328 if (n_rmap != n_actual)
2329 printk(KERN_ERR "%s: (%s) rmap %d actual %d\n",
2330 __func__, audit_msg, n_rmap, n_actual);
2331 }
2332
2333 static void audit_write_protection(struct kvm_vcpu *vcpu)
2334 {
2335 struct kvm_mmu_page *sp;
2336 struct kvm_memory_slot *slot;
2337 unsigned long *rmapp;
2338 gfn_t gfn;
2339
2340 list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
2341 if (sp->role.metaphysical)
2342 continue;
2343
2344 slot = gfn_to_memslot(vcpu->kvm, sp->gfn);
2345 gfn = unalias_gfn(vcpu->kvm, sp->gfn);
2346 rmapp = &slot->rmap[gfn - slot->base_gfn];
2347 if (*rmapp)
2348 printk(KERN_ERR "%s: (%s) shadow page has writable"
2349 " mappings: gfn %lx role %x\n",
2350 __func__, audit_msg, sp->gfn,
2351 sp->role.word);
2352 }
2353 }
2354
2355 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg)
2356 {
2357 int olddbg = dbg;
2358
2359 dbg = 0;
2360 audit_msg = msg;
2361 audit_rmap(vcpu);
2362 audit_write_protection(vcpu);
2363 audit_mappings(vcpu);
2364 dbg = olddbg;
2365 }
2366
2367 #endif
linux 2.6 git repository for openrd