Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[sfrench/cifs-2.6.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  * Copyright 2010 Red Hat, Inc. and/or its affiliates.
11  *
12  * Authors:
13  *   Yaniv Kamay  <yaniv@qumranet.com>
14  *   Avi Kivity   <avi@qumranet.com>
15  *
16  * This work is licensed under the terms of the GNU GPL, version 2.  See
17  * the COPYING file in the top-level directory.
18  *
19  */
20
21 #include "irq.h"
22 #include "mmu.h"
23 #include "x86.h"
24 #include "kvm_cache_regs.h"
25 #include "cpuid.h"
26
27 #include <linux/kvm_host.h>
28 #include <linux/types.h>
29 #include <linux/string.h>
30 #include <linux/mm.h>
31 #include <linux/highmem.h>
32 #include <linux/moduleparam.h>
33 #include <linux/export.h>
34 #include <linux/swap.h>
35 #include <linux/hugetlb.h>
36 #include <linux/compiler.h>
37 #include <linux/srcu.h>
38 #include <linux/slab.h>
39 #include <linux/sched/signal.h>
40 #include <linux/uaccess.h>
41 #include <linux/hash.h>
42 #include <linux/kern_levels.h>
43
44 #include <asm/page.h>
45 #include <asm/pat.h>
46 #include <asm/cmpxchg.h>
47 #include <asm/io.h>
48 #include <asm/vmx.h>
49 #include <asm/kvm_page_track.h>
50 #include "trace.h"
51
52 /*
53  * When setting this variable to true it enables Two-Dimensional-Paging
54  * where the hardware walks 2 page tables:
55  * 1. the guest-virtual to guest-physical
56  * 2. while doing 1. it walks guest-physical to host-physical
57  * If the hardware supports that we don't need to do shadow paging.
58  */
59 bool tdp_enabled = false;
60
61 enum {
62         AUDIT_PRE_PAGE_FAULT,
63         AUDIT_POST_PAGE_FAULT,
64         AUDIT_PRE_PTE_WRITE,
65         AUDIT_POST_PTE_WRITE,
66         AUDIT_PRE_SYNC,
67         AUDIT_POST_SYNC
68 };
69
70 #undef MMU_DEBUG
71
72 #ifdef MMU_DEBUG
73 static bool dbg = 0;
74 module_param(dbg, bool, 0644);
75
76 #define pgprintk(x...) do { if (dbg) printk(x); } while (0)
77 #define rmap_printk(x...) do { if (dbg) printk(x); } while (0)
78 #define MMU_WARN_ON(x) WARN_ON(x)
79 #else
80 #define pgprintk(x...) do { } while (0)
81 #define rmap_printk(x...) do { } while (0)
82 #define MMU_WARN_ON(x) do { } while (0)
83 #endif
84
85 #define PTE_PREFETCH_NUM                8
86
87 #define PT_FIRST_AVAIL_BITS_SHIFT 10
88 #define PT64_SECOND_AVAIL_BITS_SHIFT 52
89
90 #define PT64_LEVEL_BITS 9
91
92 #define PT64_LEVEL_SHIFT(level) \
93                 (PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS)
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_LVL_OFFSET_MASK(level) \
105         (PT32_BASE_ADDR_MASK & ((1ULL << (PAGE_SHIFT + (((level) - 1) \
106                                                 * PT32_LEVEL_BITS))) - 1))
107
108 #define PT32_INDEX(address, level)\
109         (((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))
110
111
112 #define PT64_BASE_ADDR_MASK __sme_clr((((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1)))
113 #define PT64_DIR_BASE_ADDR_MASK \
114         (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))
115 #define PT64_LVL_ADDR_MASK(level) \
116         (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + (((level) - 1) \
117                                                 * PT64_LEVEL_BITS))) - 1))
118 #define PT64_LVL_OFFSET_MASK(level) \
119         (PT64_BASE_ADDR_MASK & ((1ULL << (PAGE_SHIFT + (((level) - 1) \
120                                                 * PT64_LEVEL_BITS))) - 1))
121
122 #define PT32_BASE_ADDR_MASK PAGE_MASK
123 #define PT32_DIR_BASE_ADDR_MASK \
124         (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
125 #define PT32_LVL_ADDR_MASK(level) \
126         (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + (((level) - 1) \
127                                             * PT32_LEVEL_BITS))) - 1))
128
129 #define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | shadow_user_mask \
130                         | shadow_x_mask | shadow_nx_mask | shadow_me_mask)
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 /* The mask for the R/X bits in EPT PTEs */
138 #define PT64_EPT_READABLE_MASK                  0x1ull
139 #define PT64_EPT_EXECUTABLE_MASK                0x4ull
140
141 #include <trace/events/kvm.h>
142
143 #define CREATE_TRACE_POINTS
144 #include "mmutrace.h"
145
146 #define SPTE_HOST_WRITEABLE     (1ULL << PT_FIRST_AVAIL_BITS_SHIFT)
147 #define SPTE_MMU_WRITEABLE      (1ULL << (PT_FIRST_AVAIL_BITS_SHIFT + 1))
148
149 #define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)
150
151 /* make pte_list_desc fit well in cache line */
152 #define PTE_LIST_EXT 3
153
154 /*
155  * Return values of handle_mmio_page_fault and mmu.page_fault:
156  * RET_PF_RETRY: let CPU fault again on the address.
157  * RET_PF_EMULATE: mmio page fault, emulate the instruction directly.
158  *
159  * For handle_mmio_page_fault only:
160  * RET_PF_INVALID: the spte is invalid, let the real page fault path update it.
161  */
162 enum {
163         RET_PF_RETRY = 0,
164         RET_PF_EMULATE = 1,
165         RET_PF_INVALID = 2,
166 };
167
168 struct pte_list_desc {
169         u64 *sptes[PTE_LIST_EXT];
170         struct pte_list_desc *more;
171 };
172
173 struct kvm_shadow_walk_iterator {
174         u64 addr;
175         hpa_t shadow_addr;
176         u64 *sptep;
177         int level;
178         unsigned index;
179 };
180
181 #define for_each_shadow_entry(_vcpu, _addr, _walker)    \
182         for (shadow_walk_init(&(_walker), _vcpu, _addr);        \
183              shadow_walk_okay(&(_walker));                      \
184              shadow_walk_next(&(_walker)))
185
186 #define for_each_shadow_entry_lockless(_vcpu, _addr, _walker, spte)     \
187         for (shadow_walk_init(&(_walker), _vcpu, _addr);                \
188              shadow_walk_okay(&(_walker)) &&                            \
189                 ({ spte = mmu_spte_get_lockless(_walker.sptep); 1; });  \
190              __shadow_walk_next(&(_walker), spte))
191
192 static struct kmem_cache *pte_list_desc_cache;
193 static struct kmem_cache *mmu_page_header_cache;
194 static struct percpu_counter kvm_total_used_mmu_pages;
195
196 static u64 __read_mostly shadow_nx_mask;
197 static u64 __read_mostly shadow_x_mask; /* mutual exclusive with nx_mask */
198 static u64 __read_mostly shadow_user_mask;
199 static u64 __read_mostly shadow_accessed_mask;
200 static u64 __read_mostly shadow_dirty_mask;
201 static u64 __read_mostly shadow_mmio_mask;
202 static u64 __read_mostly shadow_mmio_value;
203 static u64 __read_mostly shadow_present_mask;
204 static u64 __read_mostly shadow_me_mask;
205
206 /*
207  * SPTEs used by MMUs without A/D bits are marked with shadow_acc_track_value.
208  * Non-present SPTEs with shadow_acc_track_value set are in place for access
209  * tracking.
210  */
211 static u64 __read_mostly shadow_acc_track_mask;
212 static const u64 shadow_acc_track_value = SPTE_SPECIAL_MASK;
213
214 /*
215  * The mask/shift to use for saving the original R/X bits when marking the PTE
216  * as not-present for access tracking purposes. We do not save the W bit as the
217  * PTEs being access tracked also need to be dirty tracked, so the W bit will be
218  * restored only when a write is attempted to the page.
219  */
220 static const u64 shadow_acc_track_saved_bits_mask = PT64_EPT_READABLE_MASK |
221                                                     PT64_EPT_EXECUTABLE_MASK;
222 static const u64 shadow_acc_track_saved_bits_shift = PT64_SECOND_AVAIL_BITS_SHIFT;
223
224 static void mmu_spte_set(u64 *sptep, u64 spte);
225 static void mmu_free_roots(struct kvm_vcpu *vcpu);
226
227 void kvm_mmu_set_mmio_spte_mask(u64 mmio_mask, u64 mmio_value)
228 {
229         BUG_ON((mmio_mask & mmio_value) != mmio_value);
230         shadow_mmio_value = mmio_value | SPTE_SPECIAL_MASK;
231         shadow_mmio_mask = mmio_mask | SPTE_SPECIAL_MASK;
232 }
233 EXPORT_SYMBOL_GPL(kvm_mmu_set_mmio_spte_mask);
234
235 static inline bool sp_ad_disabled(struct kvm_mmu_page *sp)
236 {
237         return sp->role.ad_disabled;
238 }
239
240 static inline bool spte_ad_enabled(u64 spte)
241 {
242         MMU_WARN_ON((spte & shadow_mmio_mask) == shadow_mmio_value);
243         return !(spte & shadow_acc_track_value);
244 }
245
246 static inline u64 spte_shadow_accessed_mask(u64 spte)
247 {
248         MMU_WARN_ON((spte & shadow_mmio_mask) == shadow_mmio_value);
249         return spte_ad_enabled(spte) ? shadow_accessed_mask : 0;
250 }
251
252 static inline u64 spte_shadow_dirty_mask(u64 spte)
253 {
254         MMU_WARN_ON((spte & shadow_mmio_mask) == shadow_mmio_value);
255         return spte_ad_enabled(spte) ? shadow_dirty_mask : 0;
256 }
257
258 static inline bool is_access_track_spte(u64 spte)
259 {
260         return !spte_ad_enabled(spte) && (spte & shadow_acc_track_mask) == 0;
261 }
262
263 /*
264  * the low bit of the generation number is always presumed to be zero.
265  * This disables mmio caching during memslot updates.  The concept is
266  * similar to a seqcount but instead of retrying the access we just punt
267  * and ignore the cache.
268  *
269  * spte bits 3-11 are used as bits 1-9 of the generation number,
270  * the bits 52-61 are used as bits 10-19 of the generation number.
271  */
272 #define MMIO_SPTE_GEN_LOW_SHIFT         2
273 #define MMIO_SPTE_GEN_HIGH_SHIFT        52
274
275 #define MMIO_GEN_SHIFT                  20
276 #define MMIO_GEN_LOW_SHIFT              10
277 #define MMIO_GEN_LOW_MASK               ((1 << MMIO_GEN_LOW_SHIFT) - 2)
278 #define MMIO_GEN_MASK                   ((1 << MMIO_GEN_SHIFT) - 1)
279
280 static u64 generation_mmio_spte_mask(unsigned int gen)
281 {
282         u64 mask;
283
284         WARN_ON(gen & ~MMIO_GEN_MASK);
285
286         mask = (gen & MMIO_GEN_LOW_MASK) << MMIO_SPTE_GEN_LOW_SHIFT;
287         mask |= ((u64)gen >> MMIO_GEN_LOW_SHIFT) << MMIO_SPTE_GEN_HIGH_SHIFT;
288         return mask;
289 }
290
291 static unsigned int get_mmio_spte_generation(u64 spte)
292 {
293         unsigned int gen;
294
295         spte &= ~shadow_mmio_mask;
296
297         gen = (spte >> MMIO_SPTE_GEN_LOW_SHIFT) & MMIO_GEN_LOW_MASK;
298         gen |= (spte >> MMIO_SPTE_GEN_HIGH_SHIFT) << MMIO_GEN_LOW_SHIFT;
299         return gen;
300 }
301
302 static unsigned int kvm_current_mmio_generation(struct kvm_vcpu *vcpu)
303 {
304         return kvm_vcpu_memslots(vcpu)->generation & MMIO_GEN_MASK;
305 }
306
307 static void mark_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, u64 gfn,
308                            unsigned access)
309 {
310         unsigned int gen = kvm_current_mmio_generation(vcpu);
311         u64 mask = generation_mmio_spte_mask(gen);
312
313         access &= ACC_WRITE_MASK | ACC_USER_MASK;
314         mask |= shadow_mmio_value | access | gfn << PAGE_SHIFT;
315
316         trace_mark_mmio_spte(sptep, gfn, access, gen);
317         mmu_spte_set(sptep, mask);
318 }
319
320 static bool is_mmio_spte(u64 spte)
321 {
322         return (spte & shadow_mmio_mask) == shadow_mmio_value;
323 }
324
325 static gfn_t get_mmio_spte_gfn(u64 spte)
326 {
327         u64 mask = generation_mmio_spte_mask(MMIO_GEN_MASK) | shadow_mmio_mask;
328         return (spte & ~mask) >> PAGE_SHIFT;
329 }
330
331 static unsigned get_mmio_spte_access(u64 spte)
332 {
333         u64 mask = generation_mmio_spte_mask(MMIO_GEN_MASK) | shadow_mmio_mask;
334         return (spte & ~mask) & ~PAGE_MASK;
335 }
336
337 static bool set_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, gfn_t gfn,
338                           kvm_pfn_t pfn, unsigned access)
339 {
340         if (unlikely(is_noslot_pfn(pfn))) {
341                 mark_mmio_spte(vcpu, sptep, gfn, access);
342                 return true;
343         }
344
345         return false;
346 }
347
348 static bool check_mmio_spte(struct kvm_vcpu *vcpu, u64 spte)
349 {
350         unsigned int kvm_gen, spte_gen;
351
352         kvm_gen = kvm_current_mmio_generation(vcpu);
353         spte_gen = get_mmio_spte_generation(spte);
354
355         trace_check_mmio_spte(spte, kvm_gen, spte_gen);
356         return likely(kvm_gen == spte_gen);
357 }
358
359 /*
360  * Sets the shadow PTE masks used by the MMU.
361  *
362  * Assumptions:
363  *  - Setting either @accessed_mask or @dirty_mask requires setting both
364  *  - At least one of @accessed_mask or @acc_track_mask must be set
365  */
366 void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
367                 u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 p_mask,
368                 u64 acc_track_mask, u64 me_mask)
369 {
370         BUG_ON(!dirty_mask != !accessed_mask);
371         BUG_ON(!accessed_mask && !acc_track_mask);
372         BUG_ON(acc_track_mask & shadow_acc_track_value);
373
374         shadow_user_mask = user_mask;
375         shadow_accessed_mask = accessed_mask;
376         shadow_dirty_mask = dirty_mask;
377         shadow_nx_mask = nx_mask;
378         shadow_x_mask = x_mask;
379         shadow_present_mask = p_mask;
380         shadow_acc_track_mask = acc_track_mask;
381         shadow_me_mask = me_mask;
382 }
383 EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);
384
385 static void kvm_mmu_clear_all_pte_masks(void)
386 {
387         shadow_user_mask = 0;
388         shadow_accessed_mask = 0;
389         shadow_dirty_mask = 0;
390         shadow_nx_mask = 0;
391         shadow_x_mask = 0;
392         shadow_mmio_mask = 0;
393         shadow_present_mask = 0;
394         shadow_acc_track_mask = 0;
395 }
396
397 static int is_cpuid_PSE36(void)
398 {
399         return 1;
400 }
401
402 static int is_nx(struct kvm_vcpu *vcpu)
403 {
404         return vcpu->arch.efer & EFER_NX;
405 }
406
407 static int is_shadow_present_pte(u64 pte)
408 {
409         return (pte != 0) && !is_mmio_spte(pte);
410 }
411
412 static int is_large_pte(u64 pte)
413 {
414         return pte & PT_PAGE_SIZE_MASK;
415 }
416
417 static int is_last_spte(u64 pte, int level)
418 {
419         if (level == PT_PAGE_TABLE_LEVEL)
420                 return 1;
421         if (is_large_pte(pte))
422                 return 1;
423         return 0;
424 }
425
426 static bool is_executable_pte(u64 spte)
427 {
428         return (spte & (shadow_x_mask | shadow_nx_mask)) == shadow_x_mask;
429 }
430
431 static kvm_pfn_t spte_to_pfn(u64 pte)
432 {
433         return (pte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
434 }
435
436 static gfn_t pse36_gfn_delta(u32 gpte)
437 {
438         int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT;
439
440         return (gpte & PT32_DIR_PSE36_MASK) << shift;
441 }
442
443 #ifdef CONFIG_X86_64
444 static void __set_spte(u64 *sptep, u64 spte)
445 {
446         WRITE_ONCE(*sptep, spte);
447 }
448
449 static void __update_clear_spte_fast(u64 *sptep, u64 spte)
450 {
451         WRITE_ONCE(*sptep, spte);
452 }
453
454 static u64 __update_clear_spte_slow(u64 *sptep, u64 spte)
455 {
456         return xchg(sptep, spte);
457 }
458
459 static u64 __get_spte_lockless(u64 *sptep)
460 {
461         return READ_ONCE(*sptep);
462 }
463 #else
464 union split_spte {
465         struct {
466                 u32 spte_low;
467                 u32 spte_high;
468         };
469         u64 spte;
470 };
471
472 static void count_spte_clear(u64 *sptep, u64 spte)
473 {
474         struct kvm_mmu_page *sp =  page_header(__pa(sptep));
475
476         if (is_shadow_present_pte(spte))
477                 return;
478
479         /* Ensure the spte is completely set before we increase the count */
480         smp_wmb();
481         sp->clear_spte_count++;
482 }
483
484 static void __set_spte(u64 *sptep, u64 spte)
485 {
486         union split_spte *ssptep, sspte;
487
488         ssptep = (union split_spte *)sptep;
489         sspte = (union split_spte)spte;
490
491         ssptep->spte_high = sspte.spte_high;
492
493         /*
494          * If we map the spte from nonpresent to present, We should store
495          * the high bits firstly, then set present bit, so cpu can not
496          * fetch this spte while we are setting the spte.
497          */
498         smp_wmb();
499
500         WRITE_ONCE(ssptep->spte_low, sspte.spte_low);
501 }
502
503 static void __update_clear_spte_fast(u64 *sptep, u64 spte)
504 {
505         union split_spte *ssptep, sspte;
506
507         ssptep = (union split_spte *)sptep;
508         sspte = (union split_spte)spte;
509
510         WRITE_ONCE(ssptep->spte_low, sspte.spte_low);
511
512         /*
513          * If we map the spte from present to nonpresent, we should clear
514          * present bit firstly to avoid vcpu fetch the old high bits.
515          */
516         smp_wmb();
517
518         ssptep->spte_high = sspte.spte_high;
519         count_spte_clear(sptep, spte);
520 }
521
522 static u64 __update_clear_spte_slow(u64 *sptep, u64 spte)
523 {
524         union split_spte *ssptep, sspte, orig;
525
526         ssptep = (union split_spte *)sptep;
527         sspte = (union split_spte)spte;
528
529         /* xchg acts as a barrier before the setting of the high bits */
530         orig.spte_low = xchg(&ssptep->spte_low, sspte.spte_low);
531         orig.spte_high = ssptep->spte_high;
532         ssptep->spte_high = sspte.spte_high;
533         count_spte_clear(sptep, spte);
534
535         return orig.spte;
536 }
537
538 /*
539  * The idea using the light way get the spte on x86_32 guest is from
540  * gup_get_pte(arch/x86/mm/gup.c).
541  *
542  * An spte tlb flush may be pending, because kvm_set_pte_rmapp
543  * coalesces them and we are running out of the MMU lock.  Therefore
544  * we need to protect against in-progress updates of the spte.
545  *
546  * Reading the spte while an update is in progress may get the old value
547  * for the high part of the spte.  The race is fine for a present->non-present
548  * change (because the high part of the spte is ignored for non-present spte),
549  * but for a present->present change we must reread the spte.
550  *
551  * All such changes are done in two steps (present->non-present and
552  * non-present->present), hence it is enough to count the number of
553  * present->non-present updates: if it changed while reading the spte,
554  * we might have hit the race.  This is done using clear_spte_count.
555  */
556 static u64 __get_spte_lockless(u64 *sptep)
557 {
558         struct kvm_mmu_page *sp =  page_header(__pa(sptep));
559         union split_spte spte, *orig = (union split_spte *)sptep;
560         int count;
561
562 retry:
563         count = sp->clear_spte_count;
564         smp_rmb();
565
566         spte.spte_low = orig->spte_low;
567         smp_rmb();
568
569         spte.spte_high = orig->spte_high;
570         smp_rmb();
571
572         if (unlikely(spte.spte_low != orig->spte_low ||
573               count != sp->clear_spte_count))
574                 goto retry;
575
576         return spte.spte;
577 }
578 #endif
579
580 static bool spte_can_locklessly_be_made_writable(u64 spte)
581 {
582         return (spte & (SPTE_HOST_WRITEABLE | SPTE_MMU_WRITEABLE)) ==
583                 (SPTE_HOST_WRITEABLE | SPTE_MMU_WRITEABLE);
584 }
585
586 static bool spte_has_volatile_bits(u64 spte)
587 {
588         if (!is_shadow_present_pte(spte))
589                 return false;
590
591         /*
592          * Always atomically update spte if it can be updated
593          * out of mmu-lock, it can ensure dirty bit is not lost,
594          * also, it can help us to get a stable is_writable_pte()
595          * to ensure tlb flush is not missed.
596          */
597         if (spte_can_locklessly_be_made_writable(spte) ||
598             is_access_track_spte(spte))
599                 return true;
600
601         if (spte_ad_enabled(spte)) {
602                 if ((spte & shadow_accessed_mask) == 0 ||
603                     (is_writable_pte(spte) && (spte & shadow_dirty_mask) == 0))
604                         return true;
605         }
606
607         return false;
608 }
609
610 static bool is_accessed_spte(u64 spte)
611 {
612         u64 accessed_mask = spte_shadow_accessed_mask(spte);
613
614         return accessed_mask ? spte & accessed_mask
615                              : !is_access_track_spte(spte);
616 }
617
618 static bool is_dirty_spte(u64 spte)
619 {
620         u64 dirty_mask = spte_shadow_dirty_mask(spte);
621
622         return dirty_mask ? spte & dirty_mask : spte & PT_WRITABLE_MASK;
623 }
624
625 /* Rules for using mmu_spte_set:
626  * Set the sptep from nonpresent to present.
627  * Note: the sptep being assigned *must* be either not present
628  * or in a state where the hardware will not attempt to update
629  * the spte.
630  */
631 static void mmu_spte_set(u64 *sptep, u64 new_spte)
632 {
633         WARN_ON(is_shadow_present_pte(*sptep));
634         __set_spte(sptep, new_spte);
635 }
636
637 /*
638  * Update the SPTE (excluding the PFN), but do not track changes in its
639  * accessed/dirty status.
640  */
641 static u64 mmu_spte_update_no_track(u64 *sptep, u64 new_spte)
642 {
643         u64 old_spte = *sptep;
644
645         WARN_ON(!is_shadow_present_pte(new_spte));
646
647         if (!is_shadow_present_pte(old_spte)) {
648                 mmu_spte_set(sptep, new_spte);
649                 return old_spte;
650         }
651
652         if (!spte_has_volatile_bits(old_spte))
653                 __update_clear_spte_fast(sptep, new_spte);
654         else
655                 old_spte = __update_clear_spte_slow(sptep, new_spte);
656
657         WARN_ON(spte_to_pfn(old_spte) != spte_to_pfn(new_spte));
658
659         return old_spte;
660 }
661
662 /* Rules for using mmu_spte_update:
663  * Update the state bits, it means the mapped pfn is not changed.
664  *
665  * Whenever we overwrite a writable spte with a read-only one we
666  * should flush remote TLBs. Otherwise rmap_write_protect
667  * will find a read-only spte, even though the writable spte
668  * might be cached on a CPU's TLB, the return value indicates this
669  * case.
670  *
671  * Returns true if the TLB needs to be flushed
672  */
673 static bool mmu_spte_update(u64 *sptep, u64 new_spte)
674 {
675         bool flush = false;
676         u64 old_spte = mmu_spte_update_no_track(sptep, new_spte);
677
678         if (!is_shadow_present_pte(old_spte))
679                 return false;
680
681         /*
682          * For the spte updated out of mmu-lock is safe, since
683          * we always atomically update it, see the comments in
684          * spte_has_volatile_bits().
685          */
686         if (spte_can_locklessly_be_made_writable(old_spte) &&
687               !is_writable_pte(new_spte))
688                 flush = true;
689
690         /*
691          * Flush TLB when accessed/dirty states are changed in the page tables,
692          * to guarantee consistency between TLB and page tables.
693          */
694
695         if (is_accessed_spte(old_spte) && !is_accessed_spte(new_spte)) {
696                 flush = true;
697                 kvm_set_pfn_accessed(spte_to_pfn(old_spte));
698         }
699
700         if (is_dirty_spte(old_spte) && !is_dirty_spte(new_spte)) {
701                 flush = true;
702                 kvm_set_pfn_dirty(spte_to_pfn(old_spte));
703         }
704
705         return flush;
706 }
707
708 /*
709  * Rules for using mmu_spte_clear_track_bits:
710  * It sets the sptep from present to nonpresent, and track the
711  * state bits, it is used to clear the last level sptep.
712  * Returns non-zero if the PTE was previously valid.
713  */
714 static int mmu_spte_clear_track_bits(u64 *sptep)
715 {
716         kvm_pfn_t pfn;
717         u64 old_spte = *sptep;
718
719         if (!spte_has_volatile_bits(old_spte))
720                 __update_clear_spte_fast(sptep, 0ull);
721         else
722                 old_spte = __update_clear_spte_slow(sptep, 0ull);
723
724         if (!is_shadow_present_pte(old_spte))
725                 return 0;
726
727         pfn = spte_to_pfn(old_spte);
728
729         /*
730          * KVM does not hold the refcount of the page used by
731          * kvm mmu, before reclaiming the page, we should
732          * unmap it from mmu first.
733          */
734         WARN_ON(!kvm_is_reserved_pfn(pfn) && !page_count(pfn_to_page(pfn)));
735
736         if (is_accessed_spte(old_spte))
737                 kvm_set_pfn_accessed(pfn);
738
739         if (is_dirty_spte(old_spte))
740                 kvm_set_pfn_dirty(pfn);
741
742         return 1;
743 }
744
745 /*
746  * Rules for using mmu_spte_clear_no_track:
747  * Directly clear spte without caring the state bits of sptep,
748  * it is used to set the upper level spte.
749  */
750 static void mmu_spte_clear_no_track(u64 *sptep)
751 {
752         __update_clear_spte_fast(sptep, 0ull);
753 }
754
755 static u64 mmu_spte_get_lockless(u64 *sptep)
756 {
757         return __get_spte_lockless(sptep);
758 }
759
760 static u64 mark_spte_for_access_track(u64 spte)
761 {
762         if (spte_ad_enabled(spte))
763                 return spte & ~shadow_accessed_mask;
764
765         if (is_access_track_spte(spte))
766                 return spte;
767
768         /*
769          * Making an Access Tracking PTE will result in removal of write access
770          * from the PTE. So, verify that we will be able to restore the write
771          * access in the fast page fault path later on.
772          */
773         WARN_ONCE((spte & PT_WRITABLE_MASK) &&
774                   !spte_can_locklessly_be_made_writable(spte),
775                   "kvm: Writable SPTE is not locklessly dirty-trackable\n");
776
777         WARN_ONCE(spte & (shadow_acc_track_saved_bits_mask <<
778                           shadow_acc_track_saved_bits_shift),
779                   "kvm: Access Tracking saved bit locations are not zero\n");
780
781         spte |= (spte & shadow_acc_track_saved_bits_mask) <<
782                 shadow_acc_track_saved_bits_shift;
783         spte &= ~shadow_acc_track_mask;
784
785         return spte;
786 }
787
788 /* Restore an acc-track PTE back to a regular PTE */
789 static u64 restore_acc_track_spte(u64 spte)
790 {
791         u64 new_spte = spte;
792         u64 saved_bits = (spte >> shadow_acc_track_saved_bits_shift)
793                          & shadow_acc_track_saved_bits_mask;
794
795         WARN_ON_ONCE(spte_ad_enabled(spte));
796         WARN_ON_ONCE(!is_access_track_spte(spte));
797
798         new_spte &= ~shadow_acc_track_mask;
799         new_spte &= ~(shadow_acc_track_saved_bits_mask <<
800                       shadow_acc_track_saved_bits_shift);
801         new_spte |= saved_bits;
802
803         return new_spte;
804 }
805
806 /* Returns the Accessed status of the PTE and resets it at the same time. */
807 static bool mmu_spte_age(u64 *sptep)
808 {
809         u64 spte = mmu_spte_get_lockless(sptep);
810
811         if (!is_accessed_spte(spte))
812                 return false;
813
814         if (spte_ad_enabled(spte)) {
815                 clear_bit((ffs(shadow_accessed_mask) - 1),
816                           (unsigned long *)sptep);
817         } else {
818                 /*
819                  * Capture the dirty status of the page, so that it doesn't get
820                  * lost when the SPTE is marked for access tracking.
821                  */
822                 if (is_writable_pte(spte))
823                         kvm_set_pfn_dirty(spte_to_pfn(spte));
824
825                 spte = mark_spte_for_access_track(spte);
826                 mmu_spte_update_no_track(sptep, spte);
827         }
828
829         return true;
830 }
831
832 static void walk_shadow_page_lockless_begin(struct kvm_vcpu *vcpu)
833 {
834         /*
835          * Prevent page table teardown by making any free-er wait during
836          * kvm_flush_remote_tlbs() IPI to all active vcpus.
837          */
838         local_irq_disable();
839
840         /*
841          * Make sure a following spte read is not reordered ahead of the write
842          * to vcpu->mode.
843          */
844         smp_store_mb(vcpu->mode, READING_SHADOW_PAGE_TABLES);
845 }
846
847 static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu)
848 {
849         /*
850          * Make sure the write to vcpu->mode is not reordered in front of
851          * reads to sptes.  If it does, kvm_commit_zap_page() can see us
852          * OUTSIDE_GUEST_MODE and proceed to free the shadow page table.
853          */
854         smp_store_release(&vcpu->mode, OUTSIDE_GUEST_MODE);
855         local_irq_enable();
856 }
857
858 static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
859                                   struct kmem_cache *base_cache, int min)
860 {
861         void *obj;
862
863         if (cache->nobjs >= min)
864                 return 0;
865         while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
866                 obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
867                 if (!obj)
868                         return -ENOMEM;
869                 cache->objects[cache->nobjs++] = obj;
870         }
871         return 0;
872 }
873
874 static int mmu_memory_cache_free_objects(struct kvm_mmu_memory_cache *cache)
875 {
876         return cache->nobjs;
877 }
878
879 static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc,
880                                   struct kmem_cache *cache)
881 {
882         while (mc->nobjs)
883                 kmem_cache_free(cache, mc->objects[--mc->nobjs]);
884 }
885
886 static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
887                                        int min)
888 {
889         void *page;
890
891         if (cache->nobjs >= min)
892                 return 0;
893         while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
894                 page = (void *)__get_free_page(GFP_KERNEL);
895                 if (!page)
896                         return -ENOMEM;
897                 cache->objects[cache->nobjs++] = page;
898         }
899         return 0;
900 }
901
902 static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
903 {
904         while (mc->nobjs)
905                 free_page((unsigned long)mc->objects[--mc->nobjs]);
906 }
907
908 static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
909 {
910         int r;
911
912         r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
913                                    pte_list_desc_cache, 8 + PTE_PREFETCH_NUM);
914         if (r)
915                 goto out;
916         r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
917         if (r)
918                 goto out;
919         r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
920                                    mmu_page_header_cache, 4);
921 out:
922         return r;
923 }
924
925 static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
926 {
927         mmu_free_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
928                                 pte_list_desc_cache);
929         mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache);
930         mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache,
931                                 mmu_page_header_cache);
932 }
933
934 static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
935 {
936         void *p;
937
938         BUG_ON(!mc->nobjs);
939         p = mc->objects[--mc->nobjs];
940         return p;
941 }
942
943 static struct pte_list_desc *mmu_alloc_pte_list_desc(struct kvm_vcpu *vcpu)
944 {
945         return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_list_desc_cache);
946 }
947
948 static void mmu_free_pte_list_desc(struct pte_list_desc *pte_list_desc)
949 {
950         kmem_cache_free(pte_list_desc_cache, pte_list_desc);
951 }
952
953 static gfn_t kvm_mmu_page_get_gfn(struct kvm_mmu_page *sp, int index)
954 {
955         if (!sp->role.direct)
956                 return sp->gfns[index];
957
958         return sp->gfn + (index << ((sp->role.level - 1) * PT64_LEVEL_BITS));
959 }
960
961 static void kvm_mmu_page_set_gfn(struct kvm_mmu_page *sp, int index, gfn_t gfn)
962 {
963         if (sp->role.direct)
964                 BUG_ON(gfn != kvm_mmu_page_get_gfn(sp, index));
965         else
966                 sp->gfns[index] = gfn;
967 }
968
969 /*
970  * Return the pointer to the large page information for a given gfn,
971  * handling slots that are not large page aligned.
972  */
973 static struct kvm_lpage_info *lpage_info_slot(gfn_t gfn,
974                                               struct kvm_memory_slot *slot,
975                                               int level)
976 {
977         unsigned long idx;
978
979         idx = gfn_to_index(gfn, slot->base_gfn, level);
980         return &slot->arch.lpage_info[level - 2][idx];
981 }
982
983 static void update_gfn_disallow_lpage_count(struct kvm_memory_slot *slot,
984                                             gfn_t gfn, int count)
985 {
986         struct kvm_lpage_info *linfo;
987         int i;
988
989         for (i = PT_DIRECTORY_LEVEL; i <= PT_MAX_HUGEPAGE_LEVEL; ++i) {
990                 linfo = lpage_info_slot(gfn, slot, i);
991                 linfo->disallow_lpage += count;
992                 WARN_ON(linfo->disallow_lpage < 0);
993         }
994 }
995
996 void kvm_mmu_gfn_disallow_lpage(struct kvm_memory_slot *slot, gfn_t gfn)
997 {
998         update_gfn_disallow_lpage_count(slot, gfn, 1);
999 }
1000
1001 void kvm_mmu_gfn_allow_lpage(struct kvm_memory_slot *slot, gfn_t gfn)
1002 {
1003         update_gfn_disallow_lpage_count(slot, gfn, -1);
1004 }
1005
1006 static void account_shadowed(struct kvm *kvm, struct kvm_mmu_page *sp)
1007 {
1008         struct kvm_memslots *slots;
1009         struct kvm_memory_slot *slot;
1010         gfn_t gfn;
1011
1012         kvm->arch.indirect_shadow_pages++;
1013         gfn = sp->gfn;
1014         slots = kvm_memslots_for_spte_role(kvm, sp->role);
1015         slot = __gfn_to_memslot(slots, gfn);
1016
1017         /* the non-leaf shadow pages are keeping readonly. */
1018         if (sp->role.level > PT_PAGE_TABLE_LEVEL)
1019                 return kvm_slot_page_track_add_page(kvm, slot, gfn,
1020                                                     KVM_PAGE_TRACK_WRITE);
1021
1022         kvm_mmu_gfn_disallow_lpage(slot, gfn);
1023 }
1024
1025 static void unaccount_shadowed(struct kvm *kvm, struct kvm_mmu_page *sp)
1026 {
1027         struct kvm_memslots *slots;
1028         struct kvm_memory_slot *slot;
1029         gfn_t gfn;
1030
1031         kvm->arch.indirect_shadow_pages--;
1032         gfn = sp->gfn;
1033         slots = kvm_memslots_for_spte_role(kvm, sp->role);
1034         slot = __gfn_to_memslot(slots, gfn);
1035         if (sp->role.level > PT_PAGE_TABLE_LEVEL)
1036                 return kvm_slot_page_track_remove_page(kvm, slot, gfn,
1037                                                        KVM_PAGE_TRACK_WRITE);
1038
1039         kvm_mmu_gfn_allow_lpage(slot, gfn);
1040 }
1041
1042 static bool __mmu_gfn_lpage_is_disallowed(gfn_t gfn, int level,
1043                                           struct kvm_memory_slot *slot)
1044 {
1045         struct kvm_lpage_info *linfo;
1046
1047         if (slot) {
1048                 linfo = lpage_info_slot(gfn, slot, level);
1049                 return !!linfo->disallow_lpage;
1050         }
1051
1052         return true;
1053 }
1054
1055 static bool mmu_gfn_lpage_is_disallowed(struct kvm_vcpu *vcpu, gfn_t gfn,
1056                                         int level)
1057 {
1058         struct kvm_memory_slot *slot;
1059
1060         slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
1061         return __mmu_gfn_lpage_is_disallowed(gfn, level, slot);
1062 }
1063
1064 static int host_mapping_level(struct kvm *kvm, gfn_t gfn)
1065 {
1066         unsigned long page_size;
1067         int i, ret = 0;
1068
1069         page_size = kvm_host_page_size(kvm, gfn);
1070
1071         for (i = PT_PAGE_TABLE_LEVEL; i <= PT_MAX_HUGEPAGE_LEVEL; ++i) {
1072                 if (page_size >= KVM_HPAGE_SIZE(i))
1073                         ret = i;
1074                 else
1075                         break;
1076         }
1077
1078         return ret;
1079 }
1080
1081 static inline bool memslot_valid_for_gpte(struct kvm_memory_slot *slot,
1082                                           bool no_dirty_log)
1083 {
1084         if (!slot || slot->flags & KVM_MEMSLOT_INVALID)
1085                 return false;
1086         if (no_dirty_log && slot->dirty_bitmap)
1087                 return false;
1088
1089         return true;
1090 }
1091
1092 static struct kvm_memory_slot *
1093 gfn_to_memslot_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t gfn,
1094                             bool no_dirty_log)
1095 {
1096         struct kvm_memory_slot *slot;
1097
1098         slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
1099         if (!memslot_valid_for_gpte(slot, no_dirty_log))
1100                 slot = NULL;
1101
1102         return slot;
1103 }
1104
1105 static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn,
1106                          bool *force_pt_level)
1107 {
1108         int host_level, level, max_level;
1109         struct kvm_memory_slot *slot;
1110
1111         if (unlikely(*force_pt_level))
1112                 return PT_PAGE_TABLE_LEVEL;
1113
1114         slot = kvm_vcpu_gfn_to_memslot(vcpu, large_gfn);
1115         *force_pt_level = !memslot_valid_for_gpte(slot, true);
1116         if (unlikely(*force_pt_level))
1117                 return PT_PAGE_TABLE_LEVEL;
1118
1119         host_level = host_mapping_level(vcpu->kvm, large_gfn);
1120
1121         if (host_level == PT_PAGE_TABLE_LEVEL)
1122                 return host_level;
1123
1124         max_level = min(kvm_x86_ops->get_lpage_level(), host_level);
1125
1126         for (level = PT_DIRECTORY_LEVEL; level <= max_level; ++level)
1127                 if (__mmu_gfn_lpage_is_disallowed(large_gfn, level, slot))
1128                         break;
1129
1130         return level - 1;
1131 }
1132
1133 /*
1134  * About rmap_head encoding:
1135  *
1136  * If the bit zero of rmap_head->val is clear, then it points to the only spte
1137  * in this rmap chain. Otherwise, (rmap_head->val & ~1) points to a struct
1138  * pte_list_desc containing more mappings.
1139  */
1140
1141 /*
1142  * Returns the number of pointers in the rmap chain, not counting the new one.
1143  */
1144 static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte,
1145                         struct kvm_rmap_head *rmap_head)
1146 {
1147         struct pte_list_desc *desc;
1148         int i, count = 0;
1149
1150         if (!rmap_head->val) {
1151                 rmap_printk("pte_list_add: %p %llx 0->1\n", spte, *spte);
1152                 rmap_head->val = (unsigned long)spte;
1153         } else if (!(rmap_head->val & 1)) {
1154                 rmap_printk("pte_list_add: %p %llx 1->many\n", spte, *spte);
1155                 desc = mmu_alloc_pte_list_desc(vcpu);
1156                 desc->sptes[0] = (u64 *)rmap_head->val;
1157                 desc->sptes[1] = spte;
1158                 rmap_head->val = (unsigned long)desc | 1;
1159                 ++count;
1160         } else {
1161                 rmap_printk("pte_list_add: %p %llx many->many\n", spte, *spte);
1162                 desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
1163                 while (desc->sptes[PTE_LIST_EXT-1] && desc->more) {
1164                         desc = desc->more;
1165                         count += PTE_LIST_EXT;
1166                 }
1167                 if (desc->sptes[PTE_LIST_EXT-1]) {
1168                         desc->more = mmu_alloc_pte_list_desc(vcpu);
1169                         desc = desc->more;
1170                 }
1171                 for (i = 0; desc->sptes[i]; ++i)
1172                         ++count;
1173                 desc->sptes[i] = spte;
1174         }
1175         return count;
1176 }
1177
1178 static void
1179 pte_list_desc_remove_entry(struct kvm_rmap_head *rmap_head,
1180                            struct pte_list_desc *desc, int i,
1181                            struct pte_list_desc *prev_desc)
1182 {
1183         int j;
1184
1185         for (j = PTE_LIST_EXT - 1; !desc->sptes[j] && j > i; --j)
1186                 ;
1187         desc->sptes[i] = desc->sptes[j];
1188         desc->sptes[j] = NULL;
1189         if (j != 0)
1190                 return;
1191         if (!prev_desc && !desc->more)
1192                 rmap_head->val = (unsigned long)desc->sptes[0];
1193         else
1194                 if (prev_desc)
1195                         prev_desc->more = desc->more;
1196                 else
1197                         rmap_head->val = (unsigned long)desc->more | 1;
1198         mmu_free_pte_list_desc(desc);
1199 }
1200
1201 static void pte_list_remove(u64 *spte, struct kvm_rmap_head *rmap_head)
1202 {
1203         struct pte_list_desc *desc;
1204         struct pte_list_desc *prev_desc;
1205         int i;
1206
1207         if (!rmap_head->val) {
1208                 printk(KERN_ERR "pte_list_remove: %p 0->BUG\n", spte);
1209                 BUG();
1210         } else if (!(rmap_head->val & 1)) {
1211                 rmap_printk("pte_list_remove:  %p 1->0\n", spte);
1212                 if ((u64 *)rmap_head->val != spte) {
1213                         printk(KERN_ERR "pte_list_remove:  %p 1->BUG\n", spte);
1214                         BUG();
1215                 }
1216                 rmap_head->val = 0;
1217         } else {
1218                 rmap_printk("pte_list_remove:  %p many->many\n", spte);
1219                 desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
1220                 prev_desc = NULL;
1221                 while (desc) {
1222                         for (i = 0; i < PTE_LIST_EXT && desc->sptes[i]; ++i) {
1223                                 if (desc->sptes[i] == spte) {
1224                                         pte_list_desc_remove_entry(rmap_head,
1225                                                         desc, i, prev_desc);
1226                                         return;
1227                                 }
1228                         }
1229                         prev_desc = desc;
1230                         desc = desc->more;
1231                 }
1232                 pr_err("pte_list_remove: %p many->many\n", spte);
1233                 BUG();
1234         }
1235 }
1236
1237 static struct kvm_rmap_head *__gfn_to_rmap(gfn_t gfn, int level,
1238                                            struct kvm_memory_slot *slot)
1239 {
1240         unsigned long idx;
1241
1242         idx = gfn_to_index(gfn, slot->base_gfn, level);
1243         return &slot->arch.rmap[level - PT_PAGE_TABLE_LEVEL][idx];
1244 }
1245
1246 static struct kvm_rmap_head *gfn_to_rmap(struct kvm *kvm, gfn_t gfn,
1247                                          struct kvm_mmu_page *sp)
1248 {
1249         struct kvm_memslots *slots;
1250         struct kvm_memory_slot *slot;
1251
1252         slots = kvm_memslots_for_spte_role(kvm, sp->role);
1253         slot = __gfn_to_memslot(slots, gfn);
1254         return __gfn_to_rmap(gfn, sp->role.level, slot);
1255 }
1256
1257 static bool rmap_can_add(struct kvm_vcpu *vcpu)
1258 {
1259         struct kvm_mmu_memory_cache *cache;
1260
1261         cache = &vcpu->arch.mmu_pte_list_desc_cache;
1262         return mmu_memory_cache_free_objects(cache);
1263 }
1264
1265 static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
1266 {
1267         struct kvm_mmu_page *sp;
1268         struct kvm_rmap_head *rmap_head;
1269
1270         sp = page_header(__pa(spte));
1271         kvm_mmu_page_set_gfn(sp, spte - sp->spt, gfn);
1272         rmap_head = gfn_to_rmap(vcpu->kvm, gfn, sp);
1273         return pte_list_add(vcpu, spte, rmap_head);
1274 }
1275
1276 static void rmap_remove(struct kvm *kvm, u64 *spte)
1277 {
1278         struct kvm_mmu_page *sp;
1279         gfn_t gfn;
1280         struct kvm_rmap_head *rmap_head;
1281
1282         sp = page_header(__pa(spte));
1283         gfn = kvm_mmu_page_get_gfn(sp, spte - sp->spt);
1284         rmap_head = gfn_to_rmap(kvm, gfn, sp);
1285         pte_list_remove(spte, rmap_head);
1286 }
1287
1288 /*
1289  * Used by the following functions to iterate through the sptes linked by a
1290  * rmap.  All fields are private and not assumed to be used outside.
1291  */
1292 struct rmap_iterator {
1293         /* private fields */
1294         struct pte_list_desc *desc;     /* holds the sptep if not NULL */
1295         int pos;                        /* index of the sptep */
1296 };
1297
1298 /*
1299  * Iteration must be started by this function.  This should also be used after
1300  * removing/dropping sptes from the rmap link because in such cases the
1301  * information in the itererator may not be valid.
1302  *
1303  * Returns sptep if found, NULL otherwise.
1304  */
1305 static u64 *rmap_get_first(struct kvm_rmap_head *rmap_head,
1306                            struct rmap_iterator *iter)
1307 {
1308         u64 *sptep;
1309
1310         if (!rmap_head->val)
1311                 return NULL;
1312
1313         if (!(rmap_head->val & 1)) {
1314                 iter->desc = NULL;
1315                 sptep = (u64 *)rmap_head->val;
1316                 goto out;
1317         }
1318
1319         iter->desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
1320         iter->pos = 0;
1321         sptep = iter->desc->sptes[iter->pos];
1322 out:
1323         BUG_ON(!is_shadow_present_pte(*sptep));
1324         return sptep;
1325 }
1326
1327 /*
1328  * Must be used with a valid iterator: e.g. after rmap_get_first().
1329  *
1330  * Returns sptep if found, NULL otherwise.
1331  */
1332 static u64 *rmap_get_next(struct rmap_iterator *iter)
1333 {
1334         u64 *sptep;
1335
1336         if (iter->desc) {
1337                 if (iter->pos < PTE_LIST_EXT - 1) {
1338                         ++iter->pos;
1339                         sptep = iter->desc->sptes[iter->pos];
1340                         if (sptep)
1341                                 goto out;
1342                 }
1343
1344                 iter->desc = iter->desc->more;
1345
1346                 if (iter->desc) {
1347                         iter->pos = 0;
1348                         /* desc->sptes[0] cannot be NULL */
1349                         sptep = iter->desc->sptes[iter->pos];
1350                         goto out;
1351                 }
1352         }
1353
1354         return NULL;
1355 out:
1356         BUG_ON(!is_shadow_present_pte(*sptep));
1357         return sptep;
1358 }
1359
1360 #define for_each_rmap_spte(_rmap_head_, _iter_, _spte_)                 \
1361         for (_spte_ = rmap_get_first(_rmap_head_, _iter_);              \
1362              _spte_; _spte_ = rmap_get_next(_iter_))
1363
1364 static void drop_spte(struct kvm *kvm, u64 *sptep)
1365 {
1366         if (mmu_spte_clear_track_bits(sptep))
1367                 rmap_remove(kvm, sptep);
1368 }
1369
1370
1371 static bool __drop_large_spte(struct kvm *kvm, u64 *sptep)
1372 {
1373         if (is_large_pte(*sptep)) {
1374                 WARN_ON(page_header(__pa(sptep))->role.level ==
1375                         PT_PAGE_TABLE_LEVEL);
1376                 drop_spte(kvm, sptep);
1377                 --kvm->stat.lpages;
1378                 return true;
1379         }
1380
1381         return false;
1382 }
1383
1384 static void drop_large_spte(struct kvm_vcpu *vcpu, u64 *sptep)
1385 {
1386         if (__drop_large_spte(vcpu->kvm, sptep))
1387                 kvm_flush_remote_tlbs(vcpu->kvm);
1388 }
1389
1390 /*
1391  * Write-protect on the specified @sptep, @pt_protect indicates whether
1392  * spte write-protection is caused by protecting shadow page table.
1393  *
1394  * Note: write protection is difference between dirty logging and spte
1395  * protection:
1396  * - for dirty logging, the spte can be set to writable at anytime if
1397  *   its dirty bitmap is properly set.
1398  * - for spte protection, the spte can be writable only after unsync-ing
1399  *   shadow page.
1400  *
1401  * Return true if tlb need be flushed.
1402  */
1403 static bool spte_write_protect(u64 *sptep, bool pt_protect)
1404 {
1405         u64 spte = *sptep;
1406
1407         if (!is_writable_pte(spte) &&
1408               !(pt_protect && spte_can_locklessly_be_made_writable(spte)))
1409                 return false;
1410
1411         rmap_printk("rmap_write_protect: spte %p %llx\n", sptep, *sptep);
1412
1413         if (pt_protect)
1414                 spte &= ~SPTE_MMU_WRITEABLE;
1415         spte = spte & ~PT_WRITABLE_MASK;
1416
1417         return mmu_spte_update(sptep, spte);
1418 }
1419
1420 static bool __rmap_write_protect(struct kvm *kvm,
1421                                  struct kvm_rmap_head *rmap_head,
1422                                  bool pt_protect)
1423 {
1424         u64 *sptep;
1425         struct rmap_iterator iter;
1426         bool flush = false;
1427
1428         for_each_rmap_spte(rmap_head, &iter, sptep)
1429                 flush |= spte_write_protect(sptep, pt_protect);
1430
1431         return flush;
1432 }
1433
1434 static bool spte_clear_dirty(u64 *sptep)
1435 {
1436         u64 spte = *sptep;
1437
1438         rmap_printk("rmap_clear_dirty: spte %p %llx\n", sptep, *sptep);
1439
1440         spte &= ~shadow_dirty_mask;
1441
1442         return mmu_spte_update(sptep, spte);
1443 }
1444
1445 static bool wrprot_ad_disabled_spte(u64 *sptep)
1446 {
1447         bool was_writable = test_and_clear_bit(PT_WRITABLE_SHIFT,
1448                                                (unsigned long *)sptep);
1449         if (was_writable)
1450                 kvm_set_pfn_dirty(spte_to_pfn(*sptep));
1451
1452         return was_writable;
1453 }
1454
1455 /*
1456  * Gets the GFN ready for another round of dirty logging by clearing the
1457  *      - D bit on ad-enabled SPTEs, and
1458  *      - W bit on ad-disabled SPTEs.
1459  * Returns true iff any D or W bits were cleared.
1460  */
1461 static bool __rmap_clear_dirty(struct kvm *kvm, struct kvm_rmap_head *rmap_head)
1462 {
1463         u64 *sptep;
1464         struct rmap_iterator iter;
1465         bool flush = false;
1466
1467         for_each_rmap_spte(rmap_head, &iter, sptep)
1468                 if (spte_ad_enabled(*sptep))
1469                         flush |= spte_clear_dirty(sptep);
1470                 else
1471                         flush |= wrprot_ad_disabled_spte(sptep);
1472
1473         return flush;
1474 }
1475
1476 static bool spte_set_dirty(u64 *sptep)
1477 {
1478         u64 spte = *sptep;
1479
1480         rmap_printk("rmap_set_dirty: spte %p %llx\n", sptep, *sptep);
1481
1482         spte |= shadow_dirty_mask;
1483
1484         return mmu_spte_update(sptep, spte);
1485 }
1486
1487 static bool __rmap_set_dirty(struct kvm *kvm, struct kvm_rmap_head *rmap_head)
1488 {
1489         u64 *sptep;
1490         struct rmap_iterator iter;
1491         bool flush = false;
1492
1493         for_each_rmap_spte(rmap_head, &iter, sptep)
1494                 if (spte_ad_enabled(*sptep))
1495                         flush |= spte_set_dirty(sptep);
1496
1497         return flush;
1498 }
1499
1500 /**
1501  * kvm_mmu_write_protect_pt_masked - write protect selected PT level pages
1502  * @kvm: kvm instance
1503  * @slot: slot to protect
1504  * @gfn_offset: start of the BITS_PER_LONG pages we care about
1505  * @mask: indicates which pages we should protect
1506  *
1507  * Used when we do not need to care about huge page mappings: e.g. during dirty
1508  * logging we do not have any such mappings.
1509  */
1510 static void kvm_mmu_write_protect_pt_masked(struct kvm *kvm,
1511                                      struct kvm_memory_slot *slot,
1512                                      gfn_t gfn_offset, unsigned long mask)
1513 {
1514         struct kvm_rmap_head *rmap_head;
1515
1516         while (mask) {
1517                 rmap_head = __gfn_to_rmap(slot->base_gfn + gfn_offset + __ffs(mask),
1518                                           PT_PAGE_TABLE_LEVEL, slot);
1519                 __rmap_write_protect(kvm, rmap_head, false);
1520
1521                 /* clear the first set bit */
1522                 mask &= mask - 1;
1523         }
1524 }
1525
1526 /**
1527  * kvm_mmu_clear_dirty_pt_masked - clear MMU D-bit for PT level pages, or write
1528  * protect the page if the D-bit isn't supported.
1529  * @kvm: kvm instance
1530  * @slot: slot to clear D-bit
1531  * @gfn_offset: start of the BITS_PER_LONG pages we care about
1532  * @mask: indicates which pages we should clear D-bit
1533  *
1534  * Used for PML to re-log the dirty GPAs after userspace querying dirty_bitmap.
1535  */
1536 void kvm_mmu_clear_dirty_pt_masked(struct kvm *kvm,
1537                                      struct kvm_memory_slot *slot,
1538                                      gfn_t gfn_offset, unsigned long mask)
1539 {
1540         struct kvm_rmap_head *rmap_head;
1541
1542         while (mask) {
1543                 rmap_head = __gfn_to_rmap(slot->base_gfn + gfn_offset + __ffs(mask),
1544                                           PT_PAGE_TABLE_LEVEL, slot);
1545                 __rmap_clear_dirty(kvm, rmap_head);
1546
1547                 /* clear the first set bit */
1548                 mask &= mask - 1;
1549         }
1550 }
1551 EXPORT_SYMBOL_GPL(kvm_mmu_clear_dirty_pt_masked);
1552
1553 /**
1554  * kvm_arch_mmu_enable_log_dirty_pt_masked - enable dirty logging for selected
1555  * PT level pages.
1556  *
1557  * It calls kvm_mmu_write_protect_pt_masked to write protect selected pages to
1558  * enable dirty logging for them.
1559  *
1560  * Used when we do not need to care about huge page mappings: e.g. during dirty
1561  * logging we do not have any such mappings.
1562  */
1563 void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
1564                                 struct kvm_memory_slot *slot,
1565                                 gfn_t gfn_offset, unsigned long mask)
1566 {
1567         if (kvm_x86_ops->enable_log_dirty_pt_masked)
1568                 kvm_x86_ops->enable_log_dirty_pt_masked(kvm, slot, gfn_offset,
1569                                 mask);
1570         else
1571                 kvm_mmu_write_protect_pt_masked(kvm, slot, gfn_offset, mask);
1572 }
1573
1574 /**
1575  * kvm_arch_write_log_dirty - emulate dirty page logging
1576  * @vcpu: Guest mode vcpu
1577  *
1578  * Emulate arch specific page modification logging for the
1579  * nested hypervisor
1580  */
1581 int kvm_arch_write_log_dirty(struct kvm_vcpu *vcpu)
1582 {
1583         if (kvm_x86_ops->write_log_dirty)
1584                 return kvm_x86_ops->write_log_dirty(vcpu);
1585
1586         return 0;
1587 }
1588
1589 bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
1590                                     struct kvm_memory_slot *slot, u64 gfn)
1591 {
1592         struct kvm_rmap_head *rmap_head;
1593         int i;
1594         bool write_protected = false;
1595
1596         for (i = PT_PAGE_TABLE_LEVEL; i <= PT_MAX_HUGEPAGE_LEVEL; ++i) {
1597                 rmap_head = __gfn_to_rmap(gfn, i, slot);
1598                 write_protected |= __rmap_write_protect(kvm, rmap_head, true);
1599         }
1600
1601         return write_protected;
1602 }
1603
1604 static bool rmap_write_protect(struct kvm_vcpu *vcpu, u64 gfn)
1605 {
1606         struct kvm_memory_slot *slot;
1607
1608         slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
1609         return kvm_mmu_slot_gfn_write_protect(vcpu->kvm, slot, gfn);
1610 }
1611
1612 static bool kvm_zap_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head)
1613 {
1614         u64 *sptep;
1615         struct rmap_iterator iter;
1616         bool flush = false;
1617
1618         while ((sptep = rmap_get_first(rmap_head, &iter))) {
1619                 rmap_printk("%s: spte %p %llx.\n", __func__, sptep, *sptep);
1620
1621                 drop_spte(kvm, sptep);
1622                 flush = true;
1623         }
1624
1625         return flush;
1626 }
1627
1628 static int kvm_unmap_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
1629                            struct kvm_memory_slot *slot, gfn_t gfn, int level,
1630                            unsigned long data)
1631 {
1632         return kvm_zap_rmapp(kvm, rmap_head);
1633 }
1634
1635 static int kvm_set_pte_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
1636                              struct kvm_memory_slot *slot, gfn_t gfn, int level,
1637                              unsigned long data)
1638 {
1639         u64 *sptep;
1640         struct rmap_iterator iter;
1641         int need_flush = 0;
1642         u64 new_spte;
1643         pte_t *ptep = (pte_t *)data;
1644         kvm_pfn_t new_pfn;
1645
1646         WARN_ON(pte_huge(*ptep));
1647         new_pfn = pte_pfn(*ptep);
1648
1649 restart:
1650         for_each_rmap_spte(rmap_head, &iter, sptep) {
1651                 rmap_printk("kvm_set_pte_rmapp: spte %p %llx gfn %llx (%d)\n",
1652                             sptep, *sptep, gfn, level);
1653
1654                 need_flush = 1;
1655
1656                 if (pte_write(*ptep)) {
1657                         drop_spte(kvm, sptep);
1658                         goto restart;
1659                 } else {
1660                         new_spte = *sptep & ~PT64_BASE_ADDR_MASK;
1661                         new_spte |= (u64)new_pfn << PAGE_SHIFT;
1662
1663                         new_spte &= ~PT_WRITABLE_MASK;
1664                         new_spte &= ~SPTE_HOST_WRITEABLE;
1665
1666                         new_spte = mark_spte_for_access_track(new_spte);
1667
1668                         mmu_spte_clear_track_bits(sptep);
1669                         mmu_spte_set(sptep, new_spte);
1670                 }
1671         }
1672
1673         if (need_flush)
1674                 kvm_flush_remote_tlbs(kvm);
1675
1676         return 0;
1677 }
1678
1679 struct slot_rmap_walk_iterator {
1680         /* input fields. */
1681         struct kvm_memory_slot *slot;
1682         gfn_t start_gfn;
1683         gfn_t end_gfn;
1684         int start_level;
1685         int end_level;
1686
1687         /* output fields. */
1688         gfn_t gfn;
1689         struct kvm_rmap_head *rmap;
1690         int level;
1691
1692         /* private field. */
1693         struct kvm_rmap_head *end_rmap;
1694 };
1695
1696 static void
1697 rmap_walk_init_level(struct slot_rmap_walk_iterator *iterator, int level)
1698 {
1699         iterator->level = level;
1700         iterator->gfn = iterator->start_gfn;
1701         iterator->rmap = __gfn_to_rmap(iterator->gfn, level, iterator->slot);
1702         iterator->end_rmap = __gfn_to_rmap(iterator->end_gfn, level,
1703                                            iterator->slot);
1704 }
1705
1706 static void
1707 slot_rmap_walk_init(struct slot_rmap_walk_iterator *iterator,
1708                     struct kvm_memory_slot *slot, int start_level,
1709                     int end_level, gfn_t start_gfn, gfn_t end_gfn)
1710 {
1711         iterator->slot = slot;
1712         iterator->start_level = start_level;
1713         iterator->end_level = end_level;
1714         iterator->start_gfn = start_gfn;
1715         iterator->end_gfn = end_gfn;
1716
1717         rmap_walk_init_level(iterator, iterator->start_level);
1718 }
1719
1720 static bool slot_rmap_walk_okay(struct slot_rmap_walk_iterator *iterator)
1721 {
1722         return !!iterator->rmap;
1723 }
1724
1725 static void slot_rmap_walk_next(struct slot_rmap_walk_iterator *iterator)
1726 {
1727         if (++iterator->rmap <= iterator->end_rmap) {
1728                 iterator->gfn += (1UL << KVM_HPAGE_GFN_SHIFT(iterator->level));
1729                 return;
1730         }
1731
1732         if (++iterator->level > iterator->end_level) {
1733                 iterator->rmap = NULL;
1734                 return;
1735         }
1736
1737         rmap_walk_init_level(iterator, iterator->level);
1738 }
1739
1740 #define for_each_slot_rmap_range(_slot_, _start_level_, _end_level_,    \
1741            _start_gfn, _end_gfn, _iter_)                                \
1742         for (slot_rmap_walk_init(_iter_, _slot_, _start_level_,         \
1743                                  _end_level_, _start_gfn, _end_gfn);    \
1744              slot_rmap_walk_okay(_iter_);                               \
1745              slot_rmap_walk_next(_iter_))
1746
1747 static int kvm_handle_hva_range(struct kvm *kvm,
1748                                 unsigned long start,
1749                                 unsigned long end,
1750                                 unsigned long data,
1751                                 int (*handler)(struct kvm *kvm,
1752                                                struct kvm_rmap_head *rmap_head,
1753                                                struct kvm_memory_slot *slot,
1754                                                gfn_t gfn,
1755                                                int level,
1756                                                unsigned long data))
1757 {
1758         struct kvm_memslots *slots;
1759         struct kvm_memory_slot *memslot;
1760         struct slot_rmap_walk_iterator iterator;
1761         int ret = 0;
1762         int i;
1763
1764         for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
1765                 slots = __kvm_memslots(kvm, i);
1766                 kvm_for_each_memslot(memslot, slots) {
1767                         unsigned long hva_start, hva_end;
1768                         gfn_t gfn_start, gfn_end;
1769
1770                         hva_start = max(start, memslot->userspace_addr);
1771                         hva_end = min(end, memslot->userspace_addr +
1772                                       (memslot->npages << PAGE_SHIFT));
1773                         if (hva_start >= hva_end)
1774                                 continue;
1775                         /*
1776                          * {gfn(page) | page intersects with [hva_start, hva_end)} =
1777                          * {gfn_start, gfn_start+1, ..., gfn_end-1}.
1778                          */
1779                         gfn_start = hva_to_gfn_memslot(hva_start, memslot);
1780                         gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot);
1781
1782                         for_each_slot_rmap_range(memslot, PT_PAGE_TABLE_LEVEL,
1783                                                  PT_MAX_HUGEPAGE_LEVEL,
1784                                                  gfn_start, gfn_end - 1,
1785                                                  &iterator)
1786                                 ret |= handler(kvm, iterator.rmap, memslot,
1787                                                iterator.gfn, iterator.level, data);
1788                 }
1789         }
1790
1791         return ret;
1792 }
1793
1794 static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
1795                           unsigned long data,
1796                           int (*handler)(struct kvm *kvm,
1797                                          struct kvm_rmap_head *rmap_head,
1798                                          struct kvm_memory_slot *slot,
1799                                          gfn_t gfn, int level,
1800                                          unsigned long data))
1801 {
1802         return kvm_handle_hva_range(kvm, hva, hva + 1, data, handler);
1803 }
1804
1805 int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
1806 {
1807         return kvm_handle_hva(kvm, hva, 0, kvm_unmap_rmapp);
1808 }
1809
1810 int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end)
1811 {
1812         return kvm_handle_hva_range(kvm, start, end, 0, kvm_unmap_rmapp);
1813 }
1814
1815 void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
1816 {
1817         kvm_handle_hva(kvm, hva, (unsigned long)&pte, kvm_set_pte_rmapp);
1818 }
1819
1820 static int kvm_age_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
1821                          struct kvm_memory_slot *slot, gfn_t gfn, int level,
1822                          unsigned long data)
1823 {
1824         u64 *sptep;
1825         struct rmap_iterator uninitialized_var(iter);
1826         int young = 0;
1827
1828         for_each_rmap_spte(rmap_head, &iter, sptep)
1829                 young |= mmu_spte_age(sptep);
1830
1831         trace_kvm_age_page(gfn, level, slot, young);
1832         return young;
1833 }
1834
1835 static int kvm_test_age_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
1836                               struct kvm_memory_slot *slot, gfn_t gfn,
1837                               int level, unsigned long data)
1838 {
1839         u64 *sptep;
1840         struct rmap_iterator iter;
1841
1842         for_each_rmap_spte(rmap_head, &iter, sptep)
1843                 if (is_accessed_spte(*sptep))
1844                         return 1;
1845         return 0;
1846 }
1847
1848 #define RMAP_RECYCLE_THRESHOLD 1000
1849
1850 static void rmap_recycle(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
1851 {
1852         struct kvm_rmap_head *rmap_head;
1853         struct kvm_mmu_page *sp;
1854
1855         sp = page_header(__pa(spte));
1856
1857         rmap_head = gfn_to_rmap(vcpu->kvm, gfn, sp);
1858
1859         kvm_unmap_rmapp(vcpu->kvm, rmap_head, NULL, gfn, sp->role.level, 0);
1860         kvm_flush_remote_tlbs(vcpu->kvm);
1861 }
1862
1863 int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end)
1864 {
1865         return kvm_handle_hva_range(kvm, start, end, 0, kvm_age_rmapp);
1866 }
1867
1868 int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
1869 {
1870         return kvm_handle_hva(kvm, hva, 0, kvm_test_age_rmapp);
1871 }
1872
1873 #ifdef MMU_DEBUG
1874 static int is_empty_shadow_page(u64 *spt)
1875 {
1876         u64 *pos;
1877         u64 *end;
1878
1879         for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
1880                 if (is_shadow_present_pte(*pos)) {
1881                         printk(KERN_ERR "%s: %p %llx\n", __func__,
1882                                pos, *pos);
1883                         return 0;
1884                 }
1885         return 1;
1886 }
1887 #endif
1888
1889 /*
1890  * This value is the sum of all of the kvm instances's
1891  * kvm->arch.n_used_mmu_pages values.  We need a global,
1892  * aggregate version in order to make the slab shrinker
1893  * faster
1894  */
1895 static inline void kvm_mod_used_mmu_pages(struct kvm *kvm, int nr)
1896 {
1897         kvm->arch.n_used_mmu_pages += nr;
1898         percpu_counter_add(&kvm_total_used_mmu_pages, nr);
1899 }
1900
1901 static void kvm_mmu_free_page(struct kvm_mmu_page *sp)
1902 {
1903         MMU_WARN_ON(!is_empty_shadow_page(sp->spt));
1904         hlist_del(&sp->hash_link);
1905         list_del(&sp->link);
1906         free_page((unsigned long)sp->spt);
1907         if (!sp->role.direct)
1908                 free_page((unsigned long)sp->gfns);
1909         kmem_cache_free(mmu_page_header_cache, sp);
1910 }
1911
1912 static unsigned kvm_page_table_hashfn(gfn_t gfn)
1913 {
1914         return hash_64(gfn, KVM_MMU_HASH_SHIFT);
1915 }
1916
1917 static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
1918                                     struct kvm_mmu_page *sp, u64 *parent_pte)
1919 {
1920         if (!parent_pte)
1921                 return;
1922
1923         pte_list_add(vcpu, parent_pte, &sp->parent_ptes);
1924 }
1925
1926 static void mmu_page_remove_parent_pte(struct kvm_mmu_page *sp,
1927                                        u64 *parent_pte)
1928 {
1929         pte_list_remove(parent_pte, &sp->parent_ptes);
1930 }
1931
1932 static void drop_parent_pte(struct kvm_mmu_page *sp,
1933                             u64 *parent_pte)
1934 {
1935         mmu_page_remove_parent_pte(sp, parent_pte);
1936         mmu_spte_clear_no_track(parent_pte);
1937 }
1938
1939 static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, int direct)
1940 {
1941         struct kvm_mmu_page *sp;
1942
1943         sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache);
1944         sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
1945         if (!direct)
1946                 sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
1947         set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
1948
1949         /*
1950          * The active_mmu_pages list is the FIFO list, do not move the
1951          * page until it is zapped. kvm_zap_obsolete_pages depends on
1952          * this feature. See the comments in kvm_zap_obsolete_pages().
1953          */
1954         list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
1955         kvm_mod_used_mmu_pages(vcpu->kvm, +1);
1956         return sp;
1957 }
1958
1959 static void mark_unsync(u64 *spte);
1960 static void kvm_mmu_mark_parents_unsync(struct kvm_mmu_page *sp)
1961 {
1962         u64 *sptep;
1963         struct rmap_iterator iter;
1964
1965         for_each_rmap_spte(&sp->parent_ptes, &iter, sptep) {
1966                 mark_unsync(sptep);
1967         }
1968 }
1969
1970 static void mark_unsync(u64 *spte)
1971 {
1972         struct kvm_mmu_page *sp;
1973         unsigned int index;
1974
1975         sp = page_header(__pa(spte));
1976         index = spte - sp->spt;
1977         if (__test_and_set_bit(index, sp->unsync_child_bitmap))
1978                 return;
1979         if (sp->unsync_children++)
1980                 return;
1981         kvm_mmu_mark_parents_unsync(sp);
1982 }
1983
1984 static int nonpaging_sync_page(struct kvm_vcpu *vcpu,
1985                                struct kvm_mmu_page *sp)
1986 {
1987         return 0;
1988 }
1989
1990 static void nonpaging_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
1991 {
1992 }
1993
1994 static void nonpaging_update_pte(struct kvm_vcpu *vcpu,
1995                                  struct kvm_mmu_page *sp, u64 *spte,
1996                                  const void *pte)
1997 {
1998         WARN_ON(1);
1999 }
2000
2001 #define KVM_PAGE_ARRAY_NR 16
2002
2003 struct kvm_mmu_pages {
2004         struct mmu_page_and_offset {
2005                 struct kvm_mmu_page *sp;
2006                 unsigned int idx;
2007         } page[KVM_PAGE_ARRAY_NR];
2008         unsigned int nr;
2009 };
2010
2011 static int mmu_pages_add(struct kvm_mmu_pages *pvec, struct kvm_mmu_page *sp,
2012                          int idx)
2013 {
2014         int i;
2015
2016         if (sp->unsync)
2017                 for (i=0; i < pvec->nr; i++)
2018                         if (pvec->page[i].sp == sp)
2019                                 return 0;
2020
2021         pvec->page[pvec->nr].sp = sp;
2022         pvec->page[pvec->nr].idx = idx;
2023         pvec->nr++;
2024         return (pvec->nr == KVM_PAGE_ARRAY_NR);
2025 }
2026
2027 static inline void clear_unsync_child_bit(struct kvm_mmu_page *sp, int idx)
2028 {
2029         --sp->unsync_children;
2030         WARN_ON((int)sp->unsync_children < 0);
2031         __clear_bit(idx, sp->unsync_child_bitmap);
2032 }
2033
2034 static int __mmu_unsync_walk(struct kvm_mmu_page *sp,
2035                            struct kvm_mmu_pages *pvec)
2036 {
2037         int i, ret, nr_unsync_leaf = 0;
2038
2039         for_each_set_bit(i, sp->unsync_child_bitmap, 512) {
2040                 struct kvm_mmu_page *child;
2041                 u64 ent = sp->spt[i];
2042
2043                 if (!is_shadow_present_pte(ent) || is_large_pte(ent)) {
2044                         clear_unsync_child_bit(sp, i);
2045                         continue;
2046                 }
2047
2048                 child = page_header(ent & PT64_BASE_ADDR_MASK);
2049
2050                 if (child->unsync_children) {
2051                         if (mmu_pages_add(pvec, child, i))
2052                                 return -ENOSPC;
2053
2054                         ret = __mmu_unsync_walk(child, pvec);
2055                         if (!ret) {
2056                                 clear_unsync_child_bit(sp, i);
2057                                 continue;
2058                         } else if (ret > 0) {
2059                                 nr_unsync_leaf += ret;
2060                         } else
2061                                 return ret;
2062                 } else if (child->unsync) {
2063                         nr_unsync_leaf++;
2064                         if (mmu_pages_add(pvec, child, i))
2065                                 return -ENOSPC;
2066                 } else
2067                         clear_unsync_child_bit(sp, i);
2068         }
2069
2070         return nr_unsync_leaf;
2071 }
2072
2073 #define INVALID_INDEX (-1)
2074
2075 static int mmu_unsync_walk(struct kvm_mmu_page *sp,
2076                            struct kvm_mmu_pages *pvec)
2077 {
2078         pvec->nr = 0;
2079         if (!sp->unsync_children)
2080                 return 0;
2081
2082         mmu_pages_add(pvec, sp, INVALID_INDEX);
2083         return __mmu_unsync_walk(sp, pvec);
2084 }
2085
2086 static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
2087 {
2088         WARN_ON(!sp->unsync);
2089         trace_kvm_mmu_sync_page(sp);
2090         sp->unsync = 0;
2091         --kvm->stat.mmu_unsync;
2092 }
2093
2094 static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
2095                                     struct list_head *invalid_list);
2096 static void kvm_mmu_commit_zap_page(struct kvm *kvm,
2097                                     struct list_head *invalid_list);
2098
2099 /*
2100  * NOTE: we should pay more attention on the zapped-obsolete page
2101  * (is_obsolete_sp(sp) && sp->role.invalid) when you do hash list walk
2102  * since it has been deleted from active_mmu_pages but still can be found
2103  * at hast list.
2104  *
2105  * for_each_valid_sp() has skipped that kind of pages.
2106  */
2107 #define for_each_valid_sp(_kvm, _sp, _gfn)                              \
2108         hlist_for_each_entry(_sp,                                       \
2109           &(_kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(_gfn)], hash_link) \
2110                 if (is_obsolete_sp((_kvm), (_sp)) || (_sp)->role.invalid) {    \
2111                 } else
2112
2113 #define for_each_gfn_indirect_valid_sp(_kvm, _sp, _gfn)                 \
2114         for_each_valid_sp(_kvm, _sp, _gfn)                              \
2115                 if ((_sp)->gfn != (_gfn) || (_sp)->role.direct) {} else
2116
2117 /* @sp->gfn should be write-protected at the call site */
2118 static bool __kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
2119                             struct list_head *invalid_list)
2120 {
2121         if (sp->role.cr4_pae != !!is_pae(vcpu)) {
2122                 kvm_mmu_prepare_zap_page(vcpu->kvm, sp, invalid_list);
2123                 return false;
2124         }
2125
2126         if (vcpu->arch.mmu.sync_page(vcpu, sp) == 0) {
2127                 kvm_mmu_prepare_zap_page(vcpu->kvm, sp, invalid_list);
2128                 return false;
2129         }
2130
2131         return true;
2132 }
2133
2134 static void kvm_mmu_flush_or_zap(struct kvm_vcpu *vcpu,
2135                                  struct list_head *invalid_list,
2136                                  bool remote_flush, bool local_flush)
2137 {
2138         if (!list_empty(invalid_list)) {
2139                 kvm_mmu_commit_zap_page(vcpu->kvm, invalid_list);
2140                 return;
2141         }
2142
2143         if (remote_flush)
2144                 kvm_flush_remote_tlbs(vcpu->kvm);
2145         else if (local_flush)
2146                 kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
2147 }
2148
2149 #ifdef CONFIG_KVM_MMU_AUDIT
2150 #include "mmu_audit.c"
2151 #else
2152 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, int point) { }
2153 static void mmu_audit_disable(void) { }
2154 #endif
2155
2156 static bool is_obsolete_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
2157 {
2158         return unlikely(sp->mmu_valid_gen != kvm->arch.mmu_valid_gen);
2159 }
2160
2161 static bool kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
2162                          struct list_head *invalid_list)
2163 {
2164         kvm_unlink_unsync_page(vcpu->kvm, sp);
2165         return __kvm_sync_page(vcpu, sp, invalid_list);
2166 }
2167
2168 /* @gfn should be write-protected at the call site */
2169 static bool kvm_sync_pages(struct kvm_vcpu *vcpu, gfn_t gfn,
2170                            struct list_head *invalid_list)
2171 {
2172         struct kvm_mmu_page *s;
2173         bool ret = false;
2174
2175         for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn) {
2176                 if (!s->unsync)
2177                         continue;
2178
2179                 WARN_ON(s->role.level != PT_PAGE_TABLE_LEVEL);
2180                 ret |= kvm_sync_page(vcpu, s, invalid_list);
2181         }
2182
2183         return ret;
2184 }
2185
2186 struct mmu_page_path {
2187         struct kvm_mmu_page *parent[PT64_ROOT_MAX_LEVEL];
2188         unsigned int idx[PT64_ROOT_MAX_LEVEL];
2189 };
2190
2191 #define for_each_sp(pvec, sp, parents, i)                       \
2192                 for (i = mmu_pages_first(&pvec, &parents);      \
2193                         i < pvec.nr && ({ sp = pvec.page[i].sp; 1;});   \
2194                         i = mmu_pages_next(&pvec, &parents, i))
2195
2196 static int mmu_pages_next(struct kvm_mmu_pages *pvec,
2197                           struct mmu_page_path *parents,
2198                           int i)
2199 {
2200         int n;
2201
2202         for (n = i+1; n < pvec->nr; n++) {
2203                 struct kvm_mmu_page *sp = pvec->page[n].sp;
2204                 unsigned idx = pvec->page[n].idx;
2205                 int level = sp->role.level;
2206
2207                 parents->idx[level-1] = idx;
2208                 if (level == PT_PAGE_TABLE_LEVEL)
2209                         break;
2210
2211                 parents->parent[level-2] = sp;
2212         }
2213
2214         return n;
2215 }
2216
2217 static int mmu_pages_first(struct kvm_mmu_pages *pvec,
2218                            struct mmu_page_path *parents)
2219 {
2220         struct kvm_mmu_page *sp;
2221         int level;
2222
2223         if (pvec->nr == 0)
2224                 return 0;
2225
2226         WARN_ON(pvec->page[0].idx != INVALID_INDEX);
2227
2228         sp = pvec->page[0].sp;
2229         level = sp->role.level;
2230         WARN_ON(level == PT_PAGE_TABLE_LEVEL);
2231
2232         parents->parent[level-2] = sp;
2233
2234         /* Also set up a sentinel.  Further entries in pvec are all
2235          * children of sp, so this element is never overwritten.
2236          */
2237         parents->parent[level-1] = NULL;
2238         return mmu_pages_next(pvec, parents, 0);
2239 }
2240
2241 static void mmu_pages_clear_parents(struct mmu_page_path *parents)
2242 {
2243         struct kvm_mmu_page *sp;
2244         unsigned int level = 0;
2245
2246         do {
2247                 unsigned int idx = parents->idx[level];
2248                 sp = parents->parent[level];
2249                 if (!sp)
2250                         return;
2251
2252                 WARN_ON(idx == INVALID_INDEX);
2253                 clear_unsync_child_bit(sp, idx);
2254                 level++;
2255         } while (!sp->unsync_children);
2256 }
2257
2258 static void mmu_sync_children(struct kvm_vcpu *vcpu,
2259                               struct kvm_mmu_page *parent)
2260 {
2261         int i;
2262         struct kvm_mmu_page *sp;
2263         struct mmu_page_path parents;
2264         struct kvm_mmu_pages pages;
2265         LIST_HEAD(invalid_list);
2266         bool flush = false;
2267
2268         while (mmu_unsync_walk(parent, &pages)) {
2269                 bool protected = false;
2270
2271                 for_each_sp(pages, sp, parents, i)
2272                         protected |= rmap_write_protect(vcpu, sp->gfn);
2273
2274                 if (protected) {
2275                         kvm_flush_remote_tlbs(vcpu->kvm);
2276                         flush = false;
2277                 }
2278
2279                 for_each_sp(pages, sp, parents, i) {
2280                         flush |= kvm_sync_page(vcpu, sp, &invalid_list);
2281                         mmu_pages_clear_parents(&parents);
2282                 }
2283                 if (need_resched() || spin_needbreak(&vcpu->kvm->mmu_lock)) {
2284                         kvm_mmu_flush_or_zap(vcpu, &invalid_list, false, flush);
2285                         cond_resched_lock(&vcpu->kvm->mmu_lock);
2286                         flush = false;
2287                 }
2288         }
2289
2290         kvm_mmu_flush_or_zap(vcpu, &invalid_list, false, flush);
2291 }
2292
2293 static void __clear_sp_write_flooding_count(struct kvm_mmu_page *sp)
2294 {
2295         atomic_set(&sp->write_flooding_count,  0);
2296 }
2297
2298 static void clear_sp_write_flooding_count(u64 *spte)
2299 {
2300         struct kvm_mmu_page *sp =  page_header(__pa(spte));
2301
2302         __clear_sp_write_flooding_count(sp);
2303 }
2304
2305 static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
2306                                              gfn_t gfn,
2307                                              gva_t gaddr,
2308                                              unsigned level,
2309                                              int direct,
2310                                              unsigned access)
2311 {
2312         union kvm_mmu_page_role role;
2313         unsigned quadrant;
2314         struct kvm_mmu_page *sp;
2315         bool need_sync = false;
2316         bool flush = false;
2317         int collisions = 0;
2318         LIST_HEAD(invalid_list);
2319
2320         role = vcpu->arch.mmu.base_role;
2321         role.level = level;
2322         role.direct = direct;
2323         if (role.direct)
2324                 role.cr4_pae = 0;
2325         role.access = access;
2326         if (!vcpu->arch.mmu.direct_map
2327             && vcpu->arch.mmu.root_level <= PT32_ROOT_LEVEL) {
2328                 quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
2329                 quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
2330                 role.quadrant = quadrant;
2331         }
2332         for_each_valid_sp(vcpu->kvm, sp, gfn) {
2333                 if (sp->gfn != gfn) {
2334                         collisions++;
2335                         continue;
2336                 }
2337
2338                 if (!need_sync && sp->unsync)
2339                         need_sync = true;
2340
2341                 if (sp->role.word != role.word)
2342                         continue;
2343
2344                 if (sp->unsync) {
2345                         /* The page is good, but __kvm_sync_page might still end
2346                          * up zapping it.  If so, break in order to rebuild it.
2347                          */
2348                         if (!__kvm_sync_page(vcpu, sp, &invalid_list))
2349                                 break;
2350
2351                         WARN_ON(!list_empty(&invalid_list));
2352                         kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
2353                 }
2354
2355                 if (sp->unsync_children)
2356                         kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);
2357
2358                 __clear_sp_write_flooding_count(sp);
2359                 trace_kvm_mmu_get_page(sp, false);
2360                 goto out;
2361         }
2362
2363         ++vcpu->kvm->stat.mmu_cache_miss;
2364
2365         sp = kvm_mmu_alloc_page(vcpu, direct);
2366
2367         sp->gfn = gfn;
2368         sp->role = role;
2369         hlist_add_head(&sp->hash_link,
2370                 &vcpu->kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]);
2371         if (!direct) {
2372                 /*
2373                  * we should do write protection before syncing pages
2374                  * otherwise the content of the synced shadow page may
2375                  * be inconsistent with guest page table.
2376                  */
2377                 account_shadowed(vcpu->kvm, sp);
2378                 if (level == PT_PAGE_TABLE_LEVEL &&
2379                       rmap_write_protect(vcpu, gfn))
2380                         kvm_flush_remote_tlbs(vcpu->kvm);
2381
2382                 if (level > PT_PAGE_TABLE_LEVEL && need_sync)
2383                         flush |= kvm_sync_pages(vcpu, gfn, &invalid_list);
2384         }
2385         sp->mmu_valid_gen = vcpu->kvm->arch.mmu_valid_gen;
2386         clear_page(sp->spt);
2387         trace_kvm_mmu_get_page(sp, true);
2388
2389         kvm_mmu_flush_or_zap(vcpu, &invalid_list, false, flush);
2390 out:
2391         if (collisions > vcpu->kvm->stat.max_mmu_page_hash_collisions)
2392                 vcpu->kvm->stat.max_mmu_page_hash_collisions = collisions;
2393         return sp;
2394 }
2395
2396 static void shadow_walk_init(struct kvm_shadow_walk_iterator *iterator,
2397                              struct kvm_vcpu *vcpu, u64 addr)
2398 {
2399         iterator->addr = addr;
2400         iterator->shadow_addr = vcpu->arch.mmu.root_hpa;
2401         iterator->level = vcpu->arch.mmu.shadow_root_level;
2402
2403         if (iterator->level == PT64_ROOT_4LEVEL &&
2404             vcpu->arch.mmu.root_level < PT64_ROOT_4LEVEL &&
2405             !vcpu->arch.mmu.direct_map)
2406                 --iterator->level;
2407
2408         if (iterator->level == PT32E_ROOT_LEVEL) {
2409                 iterator->shadow_addr
2410                         = vcpu->arch.mmu.pae_root[(addr >> 30) & 3];
2411                 iterator->shadow_addr &= PT64_BASE_ADDR_MASK;
2412                 --iterator->level;
2413                 if (!iterator->shadow_addr)
2414                         iterator->level = 0;
2415         }
2416 }
2417
2418 static bool shadow_walk_okay(struct kvm_shadow_walk_iterator *iterator)
2419 {
2420         if (iterator->level < PT_PAGE_TABLE_LEVEL)
2421                 return false;
2422
2423         iterator->index = SHADOW_PT_INDEX(iterator->addr, iterator->level);
2424         iterator->sptep = ((u64 *)__va(iterator->shadow_addr)) + iterator->index;
2425         return true;
2426 }
2427
2428 static void __shadow_walk_next(struct kvm_shadow_walk_iterator *iterator,
2429                                u64 spte)
2430 {
2431         if (is_last_spte(spte, iterator->level)) {
2432                 iterator->level = 0;
2433                 return;
2434         }
2435
2436         iterator->shadow_addr = spte & PT64_BASE_ADDR_MASK;
2437         --iterator->level;
2438 }
2439
2440 static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator)
2441 {
2442         __shadow_walk_next(iterator, *iterator->sptep);
2443 }
2444
2445 static void link_shadow_page(struct kvm_vcpu *vcpu, u64 *sptep,
2446                              struct kvm_mmu_page *sp)
2447 {
2448         u64 spte;
2449
2450         BUILD_BUG_ON(VMX_EPT_WRITABLE_MASK != PT_WRITABLE_MASK);
2451
2452         spte = __pa(sp->spt) | shadow_present_mask | PT_WRITABLE_MASK |
2453                shadow_user_mask | shadow_x_mask | shadow_me_mask;
2454
2455         if (sp_ad_disabled(sp))
2456                 spte |= shadow_acc_track_value;
2457         else
2458                 spte |= shadow_accessed_mask;
2459
2460         mmu_spte_set(sptep, spte);
2461
2462         mmu_page_add_parent_pte(vcpu, sp, sptep);
2463
2464         if (sp->unsync_children || sp->unsync)
2465                 mark_unsync(sptep);
2466 }
2467
2468 static void validate_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep,
2469                                    unsigned direct_access)
2470 {
2471         if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep)) {
2472                 struct kvm_mmu_page *child;
2473
2474                 /*
2475                  * For the direct sp, if the guest pte's dirty bit
2476                  * changed form clean to dirty, it will corrupt the
2477                  * sp's access: allow writable in the read-only sp,
2478                  * so we should update the spte at this point to get
2479                  * a new sp with the correct access.
2480                  */
2481                 child = page_header(*sptep & PT64_BASE_ADDR_MASK);
2482                 if (child->role.access == direct_access)
2483                         return;
2484
2485                 drop_parent_pte(child, sptep);
2486                 kvm_flush_remote_tlbs(vcpu->kvm);
2487         }
2488 }
2489
2490 static bool mmu_page_zap_pte(struct kvm *kvm, struct kvm_mmu_page *sp,
2491                              u64 *spte)
2492 {
2493         u64 pte;
2494         struct kvm_mmu_page *child;
2495
2496         pte = *spte;
2497         if (is_shadow_present_pte(pte)) {
2498                 if (is_last_spte(pte, sp->role.level)) {
2499                         drop_spte(kvm, spte);
2500                         if (is_large_pte(pte))
2501                                 --kvm->stat.lpages;
2502                 } else {
2503                         child = page_header(pte & PT64_BASE_ADDR_MASK);
2504                         drop_parent_pte(child, spte);
2505                 }
2506                 return true;
2507         }
2508
2509         if (is_mmio_spte(pte))
2510                 mmu_spte_clear_no_track(spte);
2511
2512         return false;
2513 }
2514
2515 static void kvm_mmu_page_unlink_children(struct kvm *kvm,
2516                                          struct kvm_mmu_page *sp)
2517 {
2518         unsigned i;
2519
2520         for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
2521                 mmu_page_zap_pte(kvm, sp, sp->spt + i);
2522 }
2523
2524 static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp)
2525 {
2526         u64 *sptep;
2527         struct rmap_iterator iter;
2528
2529         while ((sptep = rmap_get_first(&sp->parent_ptes, &iter)))
2530                 drop_parent_pte(sp, sptep);
2531 }
2532
2533 static int mmu_zap_unsync_children(struct kvm *kvm,
2534                                    struct kvm_mmu_page *parent,
2535                                    struct list_head *invalid_list)
2536 {
2537         int i, zapped = 0;
2538         struct mmu_page_path parents;
2539         struct kvm_mmu_pages pages;
2540
2541         if (parent->role.level == PT_PAGE_TABLE_LEVEL)
2542                 return 0;
2543
2544         while (mmu_unsync_walk(parent, &pages)) {
2545                 struct kvm_mmu_page *sp;
2546
2547                 for_each_sp(pages, sp, parents, i) {
2548                         kvm_mmu_prepare_zap_page(kvm, sp, invalid_list);
2549                         mmu_pages_clear_parents(&parents);
2550                         zapped++;
2551                 }
2552         }
2553
2554         return zapped;
2555 }
2556
2557 static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
2558                                     struct list_head *invalid_list)
2559 {
2560         int ret;
2561
2562         trace_kvm_mmu_prepare_zap_page(sp);
2563         ++kvm->stat.mmu_shadow_zapped;
2564         ret = mmu_zap_unsync_children(kvm, sp, invalid_list);
2565         kvm_mmu_page_unlink_children(kvm, sp);
2566         kvm_mmu_unlink_parents(kvm, sp);
2567
2568         if (!sp->role.invalid && !sp->role.direct)
2569                 unaccount_shadowed(kvm, sp);
2570
2571         if (sp->unsync)
2572                 kvm_unlink_unsync_page(kvm, sp);
2573         if (!sp->root_count) {
2574                 /* Count self */
2575                 ret++;
2576                 list_move(&sp->link, invalid_list);
2577                 kvm_mod_used_mmu_pages(kvm, -1);
2578         } else {
2579                 list_move(&sp->link, &kvm->arch.active_mmu_pages);
2580
2581                 /*
2582                  * The obsolete pages can not be used on any vcpus.
2583                  * See the comments in kvm_mmu_invalidate_zap_all_pages().
2584                  */
2585                 if (!sp->role.invalid && !is_obsolete_sp(kvm, sp))
2586                         kvm_reload_remote_mmus(kvm);
2587         }
2588
2589         sp->role.invalid = 1;
2590         return ret;
2591 }
2592
2593 static void kvm_mmu_commit_zap_page(struct kvm *kvm,
2594                                     struct list_head *invalid_list)
2595 {
2596         struct kvm_mmu_page *sp, *nsp;
2597
2598         if (list_empty(invalid_list))
2599                 return;
2600
2601         /*
2602          * We need to make sure everyone sees our modifications to
2603          * the page tables and see changes to vcpu->mode here. The barrier
2604          * in the kvm_flush_remote_tlbs() achieves this. This pairs
2605          * with vcpu_enter_guest and walk_shadow_page_lockless_begin/end.
2606          *
2607          * In addition, kvm_flush_remote_tlbs waits for all vcpus to exit
2608          * guest mode and/or lockless shadow page table walks.
2609          */
2610         kvm_flush_remote_tlbs(kvm);
2611
2612         list_for_each_entry_safe(sp, nsp, invalid_list, link) {
2613                 WARN_ON(!sp->role.invalid || sp->root_count);
2614                 kvm_mmu_free_page(sp);
2615         }
2616 }
2617
2618 static bool prepare_zap_oldest_mmu_page(struct kvm *kvm,
2619                                         struct list_head *invalid_list)
2620 {
2621         struct kvm_mmu_page *sp;
2622
2623         if (list_empty(&kvm->arch.active_mmu_pages))
2624                 return false;
2625
2626         sp = list_last_entry(&kvm->arch.active_mmu_pages,
2627                              struct kvm_mmu_page, link);
2628         return kvm_mmu_prepare_zap_page(kvm, sp, invalid_list);
2629 }
2630
2631 /*
2632  * Changing the number of mmu pages allocated to the vm
2633  * Note: if goal_nr_mmu_pages is too small, you will get dead lock
2634  */
2635 void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int goal_nr_mmu_pages)
2636 {
2637         LIST_HEAD(invalid_list);
2638
2639         spin_lock(&kvm->mmu_lock);
2640
2641         if (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages) {
2642                 /* Need to free some mmu pages to achieve the goal. */
2643                 while (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages)
2644                         if (!prepare_zap_oldest_mmu_page(kvm, &invalid_list))
2645                                 break;
2646
2647                 kvm_mmu_commit_zap_page(kvm, &invalid_list);
2648                 goal_nr_mmu_pages = kvm->arch.n_used_mmu_pages;
2649         }
2650
2651         kvm->arch.n_max_mmu_pages = goal_nr_mmu_pages;
2652
2653         spin_unlock(&kvm->mmu_lock);
2654 }
2655
2656 int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
2657 {
2658         struct kvm_mmu_page *sp;
2659         LIST_HEAD(invalid_list);
2660         int r;
2661
2662         pgprintk("%s: looking for gfn %llx\n", __func__, gfn);
2663         r = 0;
2664         spin_lock(&kvm->mmu_lock);
2665         for_each_gfn_indirect_valid_sp(kvm, sp, gfn) {
2666                 pgprintk("%s: gfn %llx role %x\n", __func__, gfn,
2667                          sp->role.word);
2668                 r = 1;
2669                 kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
2670         }
2671         kvm_mmu_commit_zap_page(kvm, &invalid_list);
2672         spin_unlock(&kvm->mmu_lock);
2673
2674         return r;
2675 }
2676 EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page);
2677
2678 static void kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
2679 {
2680         trace_kvm_mmu_unsync_page(sp);
2681         ++vcpu->kvm->stat.mmu_unsync;
2682         sp->unsync = 1;
2683
2684         kvm_mmu_mark_parents_unsync(sp);
2685 }
2686
2687 static bool mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn,
2688                                    bool can_unsync)
2689 {
2690         struct kvm_mmu_page *sp;
2691
2692         if (kvm_page_track_is_active(vcpu, gfn, KVM_PAGE_TRACK_WRITE))
2693                 return true;
2694
2695         for_each_gfn_indirect_valid_sp(vcpu->kvm, sp, gfn) {
2696                 if (!can_unsync)
2697                         return true;
2698
2699                 if (sp->unsync)
2700                         continue;
2701
2702                 WARN_ON(sp->role.level != PT_PAGE_TABLE_LEVEL);
2703                 kvm_unsync_page(vcpu, sp);
2704         }
2705
2706         return false;
2707 }
2708
2709 static bool kvm_is_mmio_pfn(kvm_pfn_t pfn)
2710 {
2711         if (pfn_valid(pfn))
2712                 return !is_zero_pfn(pfn) && PageReserved(pfn_to_page(pfn)) &&
2713                         /*
2714                          * Some reserved pages, such as those from NVDIMM
2715                          * DAX devices, are not for MMIO, and can be mapped
2716                          * with cached memory type for better performance.
2717                          * However, the above check misconceives those pages
2718                          * as MMIO, and results in KVM mapping them with UC
2719                          * memory type, which would hurt the performance.
2720                          * Therefore, we check the host memory type in addition
2721                          * and only treat UC/UC-/WC pages as MMIO.
2722                          */
2723                         (!pat_enabled() || pat_pfn_immune_to_uc_mtrr(pfn));
2724
2725         return true;
2726 }
2727
2728 static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
2729                     unsigned pte_access, int level,
2730                     gfn_t gfn, kvm_pfn_t pfn, bool speculative,
2731                     bool can_unsync, bool host_writable)
2732 {
2733         u64 spte = 0;
2734         int ret = 0;
2735         struct kvm_mmu_page *sp;
2736
2737         if (set_mmio_spte(vcpu, sptep, gfn, pfn, pte_access))
2738                 return 0;
2739
2740         sp = page_header(__pa(sptep));
2741         if (sp_ad_disabled(sp))
2742                 spte |= shadow_acc_track_value;
2743
2744         /*
2745          * For the EPT case, shadow_present_mask is 0 if hardware
2746          * supports exec-only page table entries.  In that case,
2747          * ACC_USER_MASK and shadow_user_mask are used to represent
2748          * read access.  See FNAME(gpte_access) in paging_tmpl.h.
2749          */
2750         spte |= shadow_present_mask;
2751         if (!speculative)
2752                 spte |= spte_shadow_accessed_mask(spte);
2753
2754         if (pte_access & ACC_EXEC_MASK)
2755                 spte |= shadow_x_mask;
2756         else
2757                 spte |= shadow_nx_mask;
2758
2759         if (pte_access & ACC_USER_MASK)
2760                 spte |= shadow_user_mask;
2761
2762         if (level > PT_PAGE_TABLE_LEVEL)
2763                 spte |= PT_PAGE_SIZE_MASK;
2764         if (tdp_enabled)
2765                 spte |= kvm_x86_ops->get_mt_mask(vcpu, gfn,
2766                         kvm_is_mmio_pfn(pfn));
2767
2768         if (host_writable)
2769                 spte |= SPTE_HOST_WRITEABLE;
2770         else
2771                 pte_access &= ~ACC_WRITE_MASK;
2772
2773         spte |= (u64)pfn << PAGE_SHIFT;
2774         spte |= shadow_me_mask;
2775
2776         if (pte_access & ACC_WRITE_MASK) {
2777
2778                 /*
2779                  * Other vcpu creates new sp in the window between
2780                  * mapping_level() and acquiring mmu-lock. We can
2781                  * allow guest to retry the access, the mapping can
2782                  * be fixed if guest refault.
2783                  */
2784                 if (level > PT_PAGE_TABLE_LEVEL &&
2785                     mmu_gfn_lpage_is_disallowed(vcpu, gfn, level))
2786                         goto done;
2787
2788                 spte |= PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE;
2789
2790                 /*
2791                  * Optimization: for pte sync, if spte was writable the hash
2792                  * lookup is unnecessary (and expensive). Write protection
2793                  * is responsibility of mmu_get_page / kvm_sync_page.
2794                  * Same reasoning can be applied to dirty page accounting.
2795                  */
2796                 if (!can_unsync && is_writable_pte(*sptep))
2797                         goto set_pte;
2798
2799                 if (mmu_need_write_protect(vcpu, gfn, can_unsync)) {
2800                         pgprintk("%s: found shadow page for %llx, marking ro\n",
2801                                  __func__, gfn);
2802                         ret = 1;
2803                         pte_access &= ~ACC_WRITE_MASK;
2804                         spte &= ~(PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE);
2805                 }
2806         }
2807
2808         if (pte_access & ACC_WRITE_MASK) {
2809                 kvm_vcpu_mark_page_dirty(vcpu, gfn);
2810                 spte |= spte_shadow_dirty_mask(spte);
2811         }
2812
2813         if (speculative)
2814                 spte = mark_spte_for_access_track(spte);
2815
2816 set_pte:
2817         if (mmu_spte_update(sptep, spte))
2818                 kvm_flush_remote_tlbs(vcpu->kvm);
2819 done:
2820         return ret;
2821 }
2822
2823 static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access,
2824                         int write_fault, int level, gfn_t gfn, kvm_pfn_t pfn,
2825                         bool speculative, bool host_writable)
2826 {
2827         int was_rmapped = 0;
2828         int rmap_count;
2829         int ret = RET_PF_RETRY;
2830
2831         pgprintk("%s: spte %llx write_fault %d gfn %llx\n", __func__,
2832                  *sptep, write_fault, gfn);
2833
2834         if (is_shadow_present_pte(*sptep)) {
2835                 /*
2836                  * If we overwrite a PTE page pointer with a 2MB PMD, unlink
2837                  * the parent of the now unreachable PTE.
2838                  */
2839                 if (level > PT_PAGE_TABLE_LEVEL &&
2840                     !is_large_pte(*sptep)) {
2841                         struct kvm_mmu_page *child;
2842                         u64 pte = *sptep;
2843
2844                         child = page_header(pte & PT64_BASE_ADDR_MASK);
2845                         drop_parent_pte(child, sptep);
2846                         kvm_flush_remote_tlbs(vcpu->kvm);
2847                 } else if (pfn != spte_to_pfn(*sptep)) {
2848                         pgprintk("hfn old %llx new %llx\n",
2849                                  spte_to_pfn(*sptep), pfn);
2850                         drop_spte(vcpu->kvm, sptep);
2851                         kvm_flush_remote_tlbs(vcpu->kvm);
2852                 } else
2853                         was_rmapped = 1;
2854         }
2855
2856         if (set_spte(vcpu, sptep, pte_access, level, gfn, pfn, speculative,
2857               true, host_writable)) {
2858                 if (write_fault)
2859                         ret = RET_PF_EMULATE;
2860                 kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
2861         }
2862
2863         if (unlikely(is_mmio_spte(*sptep)))
2864                 ret = RET_PF_EMULATE;
2865
2866         pgprintk("%s: setting spte %llx\n", __func__, *sptep);
2867         pgprintk("instantiating %s PTE (%s) at %llx (%llx) addr %p\n",
2868                  is_large_pte(*sptep)? "2MB" : "4kB",
2869                  *sptep & PT_WRITABLE_MASK ? "RW" : "R", gfn,
2870                  *sptep, sptep);
2871         if (!was_rmapped && is_large_pte(*sptep))
2872                 ++vcpu->kvm->stat.lpages;
2873
2874         if (is_shadow_present_pte(*sptep)) {
2875                 if (!was_rmapped) {
2876                         rmap_count = rmap_add(vcpu, sptep, gfn);
2877                         if (rmap_count > RMAP_RECYCLE_THRESHOLD)
2878                                 rmap_recycle(vcpu, sptep, gfn);
2879                 }
2880         }
2881
2882         kvm_release_pfn_clean(pfn);
2883
2884         return ret;
2885 }
2886
2887 static kvm_pfn_t pte_prefetch_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn,
2888                                      bool no_dirty_log)
2889 {
2890         struct kvm_memory_slot *slot;
2891
2892         slot = gfn_to_memslot_dirty_bitmap(vcpu, gfn, no_dirty_log);
2893         if (!slot)
2894                 return KVM_PFN_ERR_FAULT;
2895
2896         return gfn_to_pfn_memslot_atomic(slot, gfn);
2897 }
2898
2899 static int direct_pte_prefetch_many(struct kvm_vcpu *vcpu,
2900                                     struct kvm_mmu_page *sp,
2901                                     u64 *start, u64 *end)
2902 {
2903         struct page *pages[PTE_PREFETCH_NUM];
2904         struct kvm_memory_slot *slot;
2905         unsigned access = sp->role.access;
2906         int i, ret;
2907         gfn_t gfn;
2908
2909         gfn = kvm_mmu_page_get_gfn(sp, start - sp->spt);
2910         slot = gfn_to_memslot_dirty_bitmap(vcpu, gfn, access & ACC_WRITE_MASK);
2911         if (!slot)
2912                 return -1;
2913
2914         ret = gfn_to_page_many_atomic(slot, gfn, pages, end - start);
2915         if (ret <= 0)
2916                 return -1;
2917
2918         for (i = 0; i < ret; i++, gfn++, start++)
2919                 mmu_set_spte(vcpu, start, access, 0, sp->role.level, gfn,
2920                              page_to_pfn(pages[i]), true, true);
2921
2922         return 0;
2923 }
2924
2925 static void __direct_pte_prefetch(struct kvm_vcpu *vcpu,
2926                                   struct kvm_mmu_page *sp, u64 *sptep)
2927 {
2928         u64 *spte, *start = NULL;
2929         int i;
2930
2931         WARN_ON(!sp->role.direct);
2932
2933         i = (sptep - sp->spt) & ~(PTE_PREFETCH_NUM - 1);
2934         spte = sp->spt + i;
2935
2936         for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) {
2937                 if (is_shadow_present_pte(*spte) || spte == sptep) {
2938                         if (!start)
2939                                 continue;
2940                         if (direct_pte_prefetch_many(vcpu, sp, start, spte) < 0)
2941                                 break;
2942                         start = NULL;
2943                 } else if (!start)
2944                         start = spte;
2945         }
2946 }
2947
2948 static void direct_pte_prefetch(struct kvm_vcpu *vcpu, u64 *sptep)
2949 {
2950         struct kvm_mmu_page *sp;
2951
2952         sp = page_header(__pa(sptep));
2953
2954         /*
2955          * Without accessed bits, there's no way to distinguish between
2956          * actually accessed translations and prefetched, so disable pte
2957          * prefetch if accessed bits aren't available.
2958          */
2959         if (sp_ad_disabled(sp))
2960                 return;
2961
2962         if (sp->role.level > PT_PAGE_TABLE_LEVEL)
2963                 return;
2964
2965         __direct_pte_prefetch(vcpu, sp, sptep);
2966 }
2967
2968 static int __direct_map(struct kvm_vcpu *vcpu, int write, int map_writable,
2969                         int level, gfn_t gfn, kvm_pfn_t pfn, bool prefault)
2970 {
2971         struct kvm_shadow_walk_iterator iterator;
2972         struct kvm_mmu_page *sp;
2973         int emulate = 0;
2974         gfn_t pseudo_gfn;
2975
2976         if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
2977                 return 0;
2978
2979         for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
2980                 if (iterator.level == level) {
2981                         emulate = mmu_set_spte(vcpu, iterator.sptep, ACC_ALL,
2982                                                write, level, gfn, pfn, prefault,
2983                                                map_writable);
2984                         direct_pte_prefetch(vcpu, iterator.sptep);
2985                         ++vcpu->stat.pf_fixed;
2986                         break;
2987                 }
2988
2989                 drop_large_spte(vcpu, iterator.sptep);
2990                 if (!is_shadow_present_pte(*iterator.sptep)) {
2991                         u64 base_addr = iterator.addr;
2992
2993                         base_addr &= PT64_LVL_ADDR_MASK(iterator.level);
2994                         pseudo_gfn = base_addr >> PAGE_SHIFT;
2995                         sp = kvm_mmu_get_page(vcpu, pseudo_gfn, iterator.addr,
2996                                               iterator.level - 1, 1, ACC_ALL);
2997
2998                         link_shadow_page(vcpu, iterator.sptep, sp);
2999                 }
3000         }
3001         return emulate;
3002 }
3003
3004 static void kvm_send_hwpoison_signal(unsigned long address, struct task_struct *tsk)
3005 {
3006         siginfo_t info;
3007
3008         info.si_signo   = SIGBUS;
3009         info.si_errno   = 0;
3010         info.si_code    = BUS_MCEERR_AR;
3011         info.si_addr    = (void __user *)address;
3012         info.si_addr_lsb = PAGE_SHIFT;
3013
3014         send_sig_info(SIGBUS, &info, tsk);
3015 }
3016
3017 static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_t pfn)
3018 {
3019         /*
3020          * Do not cache the mmio info caused by writing the readonly gfn
3021          * into the spte otherwise read access on readonly gfn also can
3022          * caused mmio page fault and treat it as mmio access.
3023          */
3024         if (pfn == KVM_PFN_ERR_RO_FAULT)
3025                 return RET_PF_EMULATE;
3026
3027         if (pfn == KVM_PFN_ERR_HWPOISON) {
3028                 kvm_send_hwpoison_signal(kvm_vcpu_gfn_to_hva(vcpu, gfn), current);
3029                 return RET_PF_RETRY;
3030         }
3031
3032         return -EFAULT;
3033 }
3034
3035 static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu,
3036                                         gfn_t *gfnp, kvm_pfn_t *pfnp,
3037                                         int *levelp)
3038 {
3039         kvm_pfn_t pfn = *pfnp;
3040         gfn_t gfn = *gfnp;
3041         int level = *levelp;
3042
3043         /*
3044          * Check if it's a transparent hugepage. If this would be an
3045          * hugetlbfs page, level wouldn't be set to
3046          * PT_PAGE_TABLE_LEVEL and there would be no adjustment done
3047          * here.
3048          */
3049         if (!is_error_noslot_pfn(pfn) && !kvm_is_reserved_pfn(pfn) &&
3050             level == PT_PAGE_TABLE_LEVEL &&
3051             PageTransCompoundMap(pfn_to_page(pfn)) &&
3052             !mmu_gfn_lpage_is_disallowed(vcpu, gfn, PT_DIRECTORY_LEVEL)) {
3053                 unsigned long mask;
3054                 /*
3055                  * mmu_notifier_retry was successful and we hold the
3056                  * mmu_lock here, so the pmd can't become splitting
3057                  * from under us, and in turn
3058                  * __split_huge_page_refcount() can't run from under
3059                  * us and we can safely transfer the refcount from
3060                  * PG_tail to PG_head as we switch the pfn to tail to
3061                  * head.
3062                  */
3063                 *levelp = level = PT_DIRECTORY_LEVEL;
3064                 mask = KVM_PAGES_PER_HPAGE(level) - 1;
3065                 VM_BUG_ON((gfn & mask) != (pfn & mask));
3066                 if (pfn & mask) {
3067                         gfn &= ~mask;
3068                         *gfnp = gfn;
3069                         kvm_release_pfn_clean(pfn);
3070                         pfn &= ~mask;
3071                         kvm_get_pfn(pfn);
3072                         *pfnp = pfn;
3073                 }
3074         }
3075 }
3076
3077 static bool handle_abnormal_pfn(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,
3078                                 kvm_pfn_t pfn, unsigned access, int *ret_val)
3079 {
3080         /* The pfn is invalid, report the error! */
3081         if (unlikely(is_error_pfn(pfn))) {
3082                 *ret_val = kvm_handle_bad_page(vcpu, gfn, pfn);
3083                 return true;
3084         }
3085
3086         if (unlikely(is_noslot_pfn(pfn)))
3087                 vcpu_cache_mmio_info(vcpu, gva, gfn, access);
3088
3089         return false;
3090 }
3091
3092 static bool page_fault_can_be_fast(u32 error_code)
3093 {
3094         /*
3095          * Do not fix the mmio spte with invalid generation number which
3096          * need to be updated by slow page fault path.
3097          */
3098         if (unlikely(error_code & PFERR_RSVD_MASK))
3099                 return false;
3100
3101         /* See if the page fault is due to an NX violation */
3102         if (unlikely(((error_code & (PFERR_FETCH_MASK | PFERR_PRESENT_MASK))
3103                       == (PFERR_FETCH_MASK | PFERR_PRESENT_MASK))))
3104                 return false;
3105
3106         /*
3107          * #PF can be fast if:
3108          * 1. The shadow page table entry is not present, which could mean that
3109          *    the fault is potentially caused by access tracking (if enabled).
3110          * 2. The shadow page table entry is present and the fault
3111          *    is caused by write-protect, that means we just need change the W
3112          *    bit of the spte which can be done out of mmu-lock.
3113          *
3114          * However, if access tracking is disabled we know that a non-present
3115          * page must be a genuine page fault where we have to create a new SPTE.
3116          * So, if access tracking is disabled, we return true only for write
3117          * accesses to a present page.
3118          */
3119
3120         return shadow_acc_track_mask != 0 ||
3121                ((error_code & (PFERR_WRITE_MASK | PFERR_PRESENT_MASK))
3122                 == (PFERR_WRITE_MASK | PFERR_PRESENT_MASK));
3123 }
3124
3125 /*
3126  * Returns true if the SPTE was fixed successfully. Otherwise,
3127  * someone else modified the SPTE from its original value.
3128  */
3129 static bool
3130 fast_pf_fix_direct_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
3131                         u64 *sptep, u64 old_spte, u64 new_spte)
3132 {
3133         gfn_t gfn;
3134
3135         WARN_ON(!sp->role.direct);
3136
3137         /*
3138          * Theoretically we could also set dirty bit (and flush TLB) here in
3139          * order to eliminate unnecessary PML logging. See comments in
3140          * set_spte. But fast_page_fault is very unlikely to happen with PML
3141          * enabled, so we do not do this. This might result in the same GPA
3142          * to be logged in PML buffer again when the write really happens, and
3143          * eventually to be called by mark_page_dirty twice. But it's also no
3144          * harm. This also avoids the TLB flush needed after setting dirty bit
3145          * so non-PML cases won't be impacted.
3146          *
3147          * Compare with set_spte where instead shadow_dirty_mask is set.
3148          */
3149         if (cmpxchg64(sptep, old_spte, new_spte) != old_spte)
3150                 return false;
3151
3152         if (is_writable_pte(new_spte) && !is_writable_pte(old_spte)) {
3153                 /*
3154                  * The gfn of direct spte is stable since it is
3155                  * calculated by sp->gfn.
3156                  */
3157                 gfn = kvm_mmu_page_get_gfn(sp, sptep - sp->spt);
3158                 kvm_vcpu_mark_page_dirty(vcpu, gfn);
3159         }
3160
3161         return true;
3162 }
3163
3164 static bool is_access_allowed(u32 fault_err_code, u64 spte)
3165 {
3166         if (fault_err_code & PFERR_FETCH_MASK)
3167                 return is_executable_pte(spte);
3168
3169         if (fault_err_code & PFERR_WRITE_MASK)
3170                 return is_writable_pte(spte);
3171
3172         /* Fault was on Read access */
3173         return spte & PT_PRESENT_MASK;
3174 }
3175
3176 /*
3177  * Return value:
3178  * - true: let the vcpu to access on the same address again.
3179  * - false: let the real page fault path to fix it.
3180  */
3181 static bool fast_page_fault(struct kvm_vcpu *vcpu, gva_t gva, int level,
3182                             u32 error_code)
3183 {
3184         struct kvm_shadow_walk_iterator iterator;
3185         struct kvm_mmu_page *sp;
3186         bool fault_handled = false;
3187         u64 spte = 0ull;
3188         uint retry_count = 0;
3189
3190         if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
3191                 return false;
3192
3193         if (!page_fault_can_be_fast(error_code))
3194                 return false;
3195
3196         walk_shadow_page_lockless_begin(vcpu);
3197
3198         do {
3199                 u64 new_spte;
3200
3201                 for_each_shadow_entry_lockless(vcpu, gva, iterator, spte)
3202                         if (!is_shadow_present_pte(spte) ||
3203                             iterator.level < level)
3204                                 break;
3205
3206                 sp = page_header(__pa(iterator.sptep));
3207                 if (!is_last_spte(spte, sp->role.level))
3208                         break;
3209
3210                 /*
3211                  * Check whether the memory access that caused the fault would
3212                  * still cause it if it were to be performed right now. If not,
3213                  * then this is a spurious fault caused by TLB lazily flushed,
3214                  * or some other CPU has already fixed the PTE after the
3215                  * current CPU took the fault.
3216                  *
3217                  * Need not check the access of upper level table entries since
3218                  * they are always ACC_ALL.
3219                  */
3220                 if (is_access_allowed(error_code, spte)) {
3221                         fault_handled = true;
3222                         break;
3223                 }
3224
3225                 new_spte = spte;
3226
3227                 if (is_access_track_spte(spte))
3228                         new_spte = restore_acc_track_spte(new_spte);
3229
3230                 /*
3231                  * Currently, to simplify the code, write-protection can
3232                  * be removed in the fast path only if the SPTE was
3233                  * write-protected for dirty-logging or access tracking.
3234                  */
3235                 if ((error_code & PFERR_WRITE_MASK) &&
3236                     spte_can_locklessly_be_made_writable(spte))
3237                 {
3238                         new_spte |= PT_WRITABLE_MASK;
3239
3240                         /*
3241                          * Do not fix write-permission on the large spte.  Since
3242                          * we only dirty the first page into the dirty-bitmap in
3243                          * fast_pf_fix_direct_spte(), other pages are missed
3244                          * if its slot has dirty logging enabled.
3245                          *
3246                          * Instead, we let the slow page fault path create a
3247                          * normal spte to fix the access.
3248                          *
3249                          * See the comments in kvm_arch_commit_memory_region().
3250                          */
3251                         if (sp->role.level > PT_PAGE_TABLE_LEVEL)
3252                                 break;
3253                 }
3254
3255                 /* Verify that the fault can be handled in the fast path */
3256                 if (new_spte == spte ||
3257                     !is_access_allowed(error_code, new_spte))
3258                         break;
3259
3260                 /*
3261                  * Currently, fast page fault only works for direct mapping
3262                  * since the gfn is not stable for indirect shadow page. See
3263                  * Documentation/virtual/kvm/locking.txt to get more detail.
3264                  */
3265                 fault_handled = fast_pf_fix_direct_spte(vcpu, sp,
3266                                                         iterator.sptep, spte,
3267                                                         new_spte);
3268                 if (fault_handled)
3269                         break;
3270
3271                 if (++retry_count > 4) {
3272                         printk_once(KERN_WARNING
3273                                 "kvm: Fast #PF retrying more than 4 times.\n");
3274                         break;
3275                 }
3276
3277         } while (true);
3278
3279         trace_fast_page_fault(vcpu, gva, error_code, iterator.sptep,
3280                               spte, fault_handled);
3281         walk_shadow_page_lockless_end(vcpu);
3282
3283         return fault_handled;
3284 }
3285
3286 static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
3287                          gva_t gva, kvm_pfn_t *pfn, bool write, bool *writable);
3288 static int make_mmu_pages_available(struct kvm_vcpu *vcpu);
3289
3290 static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,
3291                          gfn_t gfn, bool prefault)
3292 {
3293         int r;
3294         int level;
3295         bool force_pt_level = false;
3296         kvm_pfn_t pfn;
3297         unsigned long mmu_seq;
3298         bool map_writable, write = error_code & PFERR_WRITE_MASK;
3299
3300         level = mapping_level(vcpu, gfn, &force_pt_level);
3301         if (likely(!force_pt_level)) {
3302                 /*
3303                  * This path builds a PAE pagetable - so we can map
3304                  * 2mb pages at maximum. Therefore check if the level
3305                  * is larger than that.
3306                  */
3307                 if (level > PT_DIRECTORY_LEVEL)
3308                         level = PT_DIRECTORY_LEVEL;
3309
3310                 gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
3311         }
3312
3313         if (fast_page_fault(vcpu, v, level, error_code))
3314                 return RET_PF_RETRY;
3315
3316         mmu_seq = vcpu->kvm->mmu_notifier_seq;
3317         smp_rmb();
3318
3319         if (try_async_pf(vcpu, prefault, gfn, v, &pfn, write, &map_writable))
3320                 return RET_PF_RETRY;
3321
3322         if (handle_abnormal_pfn(vcpu, v, gfn, pfn, ACC_ALL, &r))
3323                 return r;
3324
3325         spin_lock(&vcpu->kvm->mmu_lock);
3326         if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
3327                 goto out_unlock;
3328         if (make_mmu_pages_available(vcpu) < 0)
3329                 goto out_unlock;
3330         if (likely(!force_pt_level))
3331                 transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level);
3332         r = __direct_map(vcpu, write, map_writable, level, gfn, pfn, prefault);
3333         spin_unlock(&vcpu->kvm->mmu_lock);
3334
3335         return r;
3336
3337 out_unlock:
3338         spin_unlock(&vcpu->kvm->mmu_lock);
3339         kvm_release_pfn_clean(pfn);
3340         return RET_PF_RETRY;
3341 }
3342
3343
3344 static void mmu_free_roots(struct kvm_vcpu *vcpu)
3345 {
3346         int i;
3347         struct kvm_mmu_page *sp;
3348         LIST_HEAD(invalid_list);
3349
3350         if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
3351                 return;
3352
3353         if (vcpu->arch.mmu.shadow_root_level >= PT64_ROOT_4LEVEL &&
3354             (vcpu->arch.mmu.root_level >= PT64_ROOT_4LEVEL ||
3355              vcpu->arch.mmu.direct_map)) {
3356                 hpa_t root = vcpu->arch.mmu.root_hpa;
3357
3358                 spin_lock(&vcpu->kvm->mmu_lock);
3359                 sp = page_header(root);
3360                 --sp->root_count;
3361                 if (!sp->root_count && sp->role.invalid) {
3362                         kvm_mmu_prepare_zap_page(vcpu->kvm, sp, &invalid_list);
3363                         kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
3364                 }
3365                 spin_unlock(&vcpu->kvm->mmu_lock);
3366                 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
3367                 return;
3368         }
3369
3370         spin_lock(&vcpu->kvm->mmu_lock);
3371         for (i = 0; i < 4; ++i) {
3372                 hpa_t root = vcpu->arch.mmu.pae_root[i];
3373
3374                 if (root) {
3375                         root &= PT64_BASE_ADDR_MASK;
3376                         sp = page_header(root);
3377                         --sp->root_count;
3378                         if (!sp->root_count && sp->role.invalid)
3379                                 kvm_mmu_prepare_zap_page(vcpu->kvm, sp,
3380                                                          &invalid_list);
3381                 }
3382                 vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
3383         }
3384         kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
3385         spin_unlock(&vcpu->kvm->mmu_lock);
3386         vcpu->arch.mmu.root_hpa = INVALID_PAGE;
3387 }
3388
3389 static