1 // SPDX-License-Identifier: GPL-2.0-only
3 * Kernel-based Virtual Machine driver for Linux
5 * This module enables machines with Intel VT-x extensions to run virtual
6 * machines without emulation or binary translation.
10 * Copyright (C) 2006 Qumranet, Inc.
11 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
14 * Yaniv Kamay <yaniv@qumranet.com>
15 * Avi Kivity <avi@qumranet.com>
21 #include "mmu_internal.h"
24 #include "kvm_cache_regs.h"
25 #include "kvm_emulate.h"
29 #include <linux/kvm_host.h>
30 #include <linux/types.h>
31 #include <linux/string.h>
33 #include <linux/highmem.h>
34 #include <linux/moduleparam.h>
35 #include <linux/export.h>
36 #include <linux/swap.h>
37 #include <linux/hugetlb.h>
38 #include <linux/compiler.h>
39 #include <linux/srcu.h>
40 #include <linux/slab.h>
41 #include <linux/sched/signal.h>
42 #include <linux/uaccess.h>
43 #include <linux/hash.h>
44 #include <linux/kern_levels.h>
45 #include <linux/kthread.h>
48 #include <asm/memtype.h>
49 #include <asm/cmpxchg.h>
51 #include <asm/set_memory.h>
53 #include <asm/kvm_page_track.h>
58 extern bool itlb_multihit_kvm_mitigation;
60 int __read_mostly nx_huge_pages = -1;
61 static uint __read_mostly nx_huge_pages_recovery_period_ms;
62 #ifdef CONFIG_PREEMPT_RT
63 /* Recovery can cause latency spikes, disable it for PREEMPT_RT. */
64 static uint __read_mostly nx_huge_pages_recovery_ratio = 0;
66 static uint __read_mostly nx_huge_pages_recovery_ratio = 60;
69 static int set_nx_huge_pages(const char *val, const struct kernel_param *kp);
70 static int set_nx_huge_pages_recovery_param(const char *val, const struct kernel_param *kp);
72 static const struct kernel_param_ops nx_huge_pages_ops = {
73 .set = set_nx_huge_pages,
74 .get = param_get_bool,
77 static const struct kernel_param_ops nx_huge_pages_recovery_param_ops = {
78 .set = set_nx_huge_pages_recovery_param,
79 .get = param_get_uint,
82 module_param_cb(nx_huge_pages, &nx_huge_pages_ops, &nx_huge_pages, 0644);
83 __MODULE_PARM_TYPE(nx_huge_pages, "bool");
84 module_param_cb(nx_huge_pages_recovery_ratio, &nx_huge_pages_recovery_param_ops,
85 &nx_huge_pages_recovery_ratio, 0644);
86 __MODULE_PARM_TYPE(nx_huge_pages_recovery_ratio, "uint");
87 module_param_cb(nx_huge_pages_recovery_period_ms, &nx_huge_pages_recovery_param_ops,
88 &nx_huge_pages_recovery_period_ms, 0644);
89 __MODULE_PARM_TYPE(nx_huge_pages_recovery_period_ms, "uint");
91 static bool __read_mostly force_flush_and_sync_on_reuse;
92 module_param_named(flush_on_reuse, force_flush_and_sync_on_reuse, bool, 0644);
95 * When setting this variable to true it enables Two-Dimensional-Paging
96 * where the hardware walks 2 page tables:
97 * 1. the guest-virtual to guest-physical
98 * 2. while doing 1. it walks guest-physical to host-physical
99 * If the hardware supports that we don't need to do shadow paging.
101 bool tdp_enabled = false;
103 static int max_huge_page_level __read_mostly;
104 static int tdp_root_level __read_mostly;
105 static int max_tdp_level __read_mostly;
109 module_param(dbg, bool, 0644);
112 #define PTE_PREFETCH_NUM 8
114 #define PT32_LEVEL_BITS 10
116 #define PT32_LEVEL_SHIFT(level) \
117 (PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS)
119 #define PT32_LVL_OFFSET_MASK(level) \
120 (PT32_BASE_ADDR_MASK & ((1ULL << (PAGE_SHIFT + (((level) - 1) \
121 * PT32_LEVEL_BITS))) - 1))
123 #define PT32_INDEX(address, level)\
124 (((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))
127 #define PT32_BASE_ADDR_MASK PAGE_MASK
128 #define PT32_DIR_BASE_ADDR_MASK \
129 (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
130 #define PT32_LVL_ADDR_MASK(level) \
131 (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + (((level) - 1) \
132 * PT32_LEVEL_BITS))) - 1))
134 #include <trace/events/kvm.h>
136 /* make pte_list_desc fit well in cache lines */
137 #define PTE_LIST_EXT 14
140 * Slight optimization of cacheline layout, by putting `more' and `spte_count'
141 * at the start; then accessing it will only use one single cacheline for
142 * either full (entries==PTE_LIST_EXT) case or entries<=6.
144 struct pte_list_desc {
145 struct pte_list_desc *more;
147 * Stores number of entries stored in the pte_list_desc. No need to be
148 * u64 but just for easier alignment. When PTE_LIST_EXT, means full.
151 u64 *sptes[PTE_LIST_EXT];
154 struct kvm_shadow_walk_iterator {
162 #define for_each_shadow_entry_using_root(_vcpu, _root, _addr, _walker) \
163 for (shadow_walk_init_using_root(&(_walker), (_vcpu), \
165 shadow_walk_okay(&(_walker)); \
166 shadow_walk_next(&(_walker)))
168 #define for_each_shadow_entry(_vcpu, _addr, _walker) \
169 for (shadow_walk_init(&(_walker), _vcpu, _addr); \
170 shadow_walk_okay(&(_walker)); \
171 shadow_walk_next(&(_walker)))
173 #define for_each_shadow_entry_lockless(_vcpu, _addr, _walker, spte) \
174 for (shadow_walk_init(&(_walker), _vcpu, _addr); \
175 shadow_walk_okay(&(_walker)) && \
176 ({ spte = mmu_spte_get_lockless(_walker.sptep); 1; }); \
177 __shadow_walk_next(&(_walker), spte))
179 static struct kmem_cache *pte_list_desc_cache;
180 struct kmem_cache *mmu_page_header_cache;
181 static struct percpu_counter kvm_total_used_mmu_pages;
183 static void mmu_spte_set(u64 *sptep, u64 spte);
185 struct kvm_mmu_role_regs {
186 const unsigned long cr0;
187 const unsigned long cr4;
191 #define CREATE_TRACE_POINTS
192 #include "mmutrace.h"
195 * Yes, lot's of underscores. They're a hint that you probably shouldn't be
196 * reading from the role_regs. Once the root_role is constructed, it becomes
197 * the single source of truth for the MMU's state.
199 #define BUILD_MMU_ROLE_REGS_ACCESSOR(reg, name, flag) \
200 static inline bool __maybe_unused \
201 ____is_##reg##_##name(const struct kvm_mmu_role_regs *regs) \
203 return !!(regs->reg & flag); \
205 BUILD_MMU_ROLE_REGS_ACCESSOR(cr0, pg, X86_CR0_PG);
206 BUILD_MMU_ROLE_REGS_ACCESSOR(cr0, wp, X86_CR0_WP);
207 BUILD_MMU_ROLE_REGS_ACCESSOR(cr4, pse, X86_CR4_PSE);
208 BUILD_MMU_ROLE_REGS_ACCESSOR(cr4, pae, X86_CR4_PAE);
209 BUILD_MMU_ROLE_REGS_ACCESSOR(cr4, smep, X86_CR4_SMEP);
210 BUILD_MMU_ROLE_REGS_ACCESSOR(cr4, smap, X86_CR4_SMAP);
211 BUILD_MMU_ROLE_REGS_ACCESSOR(cr4, pke, X86_CR4_PKE);
212 BUILD_MMU_ROLE_REGS_ACCESSOR(cr4, la57, X86_CR4_LA57);
213 BUILD_MMU_ROLE_REGS_ACCESSOR(efer, nx, EFER_NX);
214 BUILD_MMU_ROLE_REGS_ACCESSOR(efer, lma, EFER_LMA);
217 * The MMU itself (with a valid role) is the single source of truth for the
218 * MMU. Do not use the regs used to build the MMU/role, nor the vCPU. The
219 * regs don't account for dependencies, e.g. clearing CR4 bits if CR0.PG=1,
220 * and the vCPU may be incorrect/irrelevant.
222 #define BUILD_MMU_ROLE_ACCESSOR(base_or_ext, reg, name) \
223 static inline bool __maybe_unused is_##reg##_##name(struct kvm_mmu *mmu) \
225 return !!(mmu->cpu_role. base_or_ext . reg##_##name); \
227 BUILD_MMU_ROLE_ACCESSOR(base, cr0, wp);
228 BUILD_MMU_ROLE_ACCESSOR(ext, cr4, pse);
229 BUILD_MMU_ROLE_ACCESSOR(ext, cr4, smep);
230 BUILD_MMU_ROLE_ACCESSOR(ext, cr4, smap);
231 BUILD_MMU_ROLE_ACCESSOR(ext, cr4, pke);
232 BUILD_MMU_ROLE_ACCESSOR(ext, cr4, la57);
233 BUILD_MMU_ROLE_ACCESSOR(base, efer, nx);
234 BUILD_MMU_ROLE_ACCESSOR(ext, efer, lma);
236 static inline bool is_cr0_pg(struct kvm_mmu *mmu)
238 return mmu->cpu_role.base.level > 0;
241 static inline bool is_cr4_pae(struct kvm_mmu *mmu)
243 return !mmu->cpu_role.base.has_4_byte_gpte;
246 static struct kvm_mmu_role_regs vcpu_to_role_regs(struct kvm_vcpu *vcpu)
248 struct kvm_mmu_role_regs regs = {
249 .cr0 = kvm_read_cr0_bits(vcpu, KVM_MMU_CR0_ROLE_BITS),
250 .cr4 = kvm_read_cr4_bits(vcpu, KVM_MMU_CR4_ROLE_BITS),
251 .efer = vcpu->arch.efer,
257 static inline bool kvm_available_flush_tlb_with_range(void)
259 return kvm_x86_ops.tlb_remote_flush_with_range;
262 static void kvm_flush_remote_tlbs_with_range(struct kvm *kvm,
263 struct kvm_tlb_range *range)
267 if (range && kvm_x86_ops.tlb_remote_flush_with_range)
268 ret = static_call(kvm_x86_tlb_remote_flush_with_range)(kvm, range);
271 kvm_flush_remote_tlbs(kvm);
274 void kvm_flush_remote_tlbs_with_address(struct kvm *kvm,
275 u64 start_gfn, u64 pages)
277 struct kvm_tlb_range range;
279 range.start_gfn = start_gfn;
282 kvm_flush_remote_tlbs_with_range(kvm, &range);
285 static void mark_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, u64 gfn,
288 u64 spte = make_mmio_spte(vcpu, gfn, access);
290 trace_mark_mmio_spte(sptep, gfn, spte);
291 mmu_spte_set(sptep, spte);
294 static gfn_t get_mmio_spte_gfn(u64 spte)
296 u64 gpa = spte & shadow_nonpresent_or_rsvd_lower_gfn_mask;
298 gpa |= (spte >> SHADOW_NONPRESENT_OR_RSVD_MASK_LEN)
299 & shadow_nonpresent_or_rsvd_mask;
301 return gpa >> PAGE_SHIFT;
304 static unsigned get_mmio_spte_access(u64 spte)
306 return spte & shadow_mmio_access_mask;
309 static bool check_mmio_spte(struct kvm_vcpu *vcpu, u64 spte)
311 u64 kvm_gen, spte_gen, gen;
313 gen = kvm_vcpu_memslots(vcpu)->generation;
314 if (unlikely(gen & KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS))
317 kvm_gen = gen & MMIO_SPTE_GEN_MASK;
318 spte_gen = get_mmio_spte_generation(spte);
320 trace_check_mmio_spte(spte, kvm_gen, spte_gen);
321 return likely(kvm_gen == spte_gen);
324 static int is_cpuid_PSE36(void)
329 static gfn_t pse36_gfn_delta(u32 gpte)
331 int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT;
333 return (gpte & PT32_DIR_PSE36_MASK) << shift;
337 static void __set_spte(u64 *sptep, u64 spte)
339 WRITE_ONCE(*sptep, spte);
342 static void __update_clear_spte_fast(u64 *sptep, u64 spte)
344 WRITE_ONCE(*sptep, spte);
347 static u64 __update_clear_spte_slow(u64 *sptep, u64 spte)
349 return xchg(sptep, spte);
352 static u64 __get_spte_lockless(u64 *sptep)
354 return READ_ONCE(*sptep);
365 static void count_spte_clear(u64 *sptep, u64 spte)
367 struct kvm_mmu_page *sp = sptep_to_sp(sptep);
369 if (is_shadow_present_pte(spte))
372 /* Ensure the spte is completely set before we increase the count */
374 sp->clear_spte_count++;
377 static void __set_spte(u64 *sptep, u64 spte)
379 union split_spte *ssptep, sspte;
381 ssptep = (union split_spte *)sptep;
382 sspte = (union split_spte)spte;
384 ssptep->spte_high = sspte.spte_high;
387 * If we map the spte from nonpresent to present, We should store
388 * the high bits firstly, then set present bit, so cpu can not
389 * fetch this spte while we are setting the spte.
393 WRITE_ONCE(ssptep->spte_low, sspte.spte_low);
396 static void __update_clear_spte_fast(u64 *sptep, u64 spte)
398 union split_spte *ssptep, sspte;
400 ssptep = (union split_spte *)sptep;
401 sspte = (union split_spte)spte;
403 WRITE_ONCE(ssptep->spte_low, sspte.spte_low);
406 * If we map the spte from present to nonpresent, we should clear
407 * present bit firstly to avoid vcpu fetch the old high bits.
411 ssptep->spte_high = sspte.spte_high;
412 count_spte_clear(sptep, spte);
415 static u64 __update_clear_spte_slow(u64 *sptep, u64 spte)
417 union split_spte *ssptep, sspte, orig;
419 ssptep = (union split_spte *)sptep;
420 sspte = (union split_spte)spte;
422 /* xchg acts as a barrier before the setting of the high bits */
423 orig.spte_low = xchg(&ssptep->spte_low, sspte.spte_low);
424 orig.spte_high = ssptep->spte_high;
425 ssptep->spte_high = sspte.spte_high;
426 count_spte_clear(sptep, spte);
432 * The idea using the light way get the spte on x86_32 guest is from
433 * gup_get_pte (mm/gup.c).
435 * An spte tlb flush may be pending, because kvm_set_pte_rmapp
436 * coalesces them and we are running out of the MMU lock. Therefore
437 * we need to protect against in-progress updates of the spte.
439 * Reading the spte while an update is in progress may get the old value
440 * for the high part of the spte. The race is fine for a present->non-present
441 * change (because the high part of the spte is ignored for non-present spte),
442 * but for a present->present change we must reread the spte.
444 * All such changes are done in two steps (present->non-present and
445 * non-present->present), hence it is enough to count the number of
446 * present->non-present updates: if it changed while reading the spte,
447 * we might have hit the race. This is done using clear_spte_count.
449 static u64 __get_spte_lockless(u64 *sptep)
451 struct kvm_mmu_page *sp = sptep_to_sp(sptep);
452 union split_spte spte, *orig = (union split_spte *)sptep;
456 count = sp->clear_spte_count;
459 spte.spte_low = orig->spte_low;
462 spte.spte_high = orig->spte_high;
465 if (unlikely(spte.spte_low != orig->spte_low ||
466 count != sp->clear_spte_count))
473 /* Rules for using mmu_spte_set:
474 * Set the sptep from nonpresent to present.
475 * Note: the sptep being assigned *must* be either not present
476 * or in a state where the hardware will not attempt to update
479 static void mmu_spte_set(u64 *sptep, u64 new_spte)
481 WARN_ON(is_shadow_present_pte(*sptep));
482 __set_spte(sptep, new_spte);
486 * Update the SPTE (excluding the PFN), but do not track changes in its
487 * accessed/dirty status.
489 static u64 mmu_spte_update_no_track(u64 *sptep, u64 new_spte)
491 u64 old_spte = *sptep;
493 WARN_ON(!is_shadow_present_pte(new_spte));
494 check_spte_writable_invariants(new_spte);
496 if (!is_shadow_present_pte(old_spte)) {
497 mmu_spte_set(sptep, new_spte);
501 if (!spte_has_volatile_bits(old_spte))
502 __update_clear_spte_fast(sptep, new_spte);
504 old_spte = __update_clear_spte_slow(sptep, new_spte);
506 WARN_ON(spte_to_pfn(old_spte) != spte_to_pfn(new_spte));
511 /* Rules for using mmu_spte_update:
512 * Update the state bits, it means the mapped pfn is not changed.
514 * Whenever an MMU-writable SPTE is overwritten with a read-only SPTE, remote
515 * TLBs must be flushed. Otherwise rmap_write_protect will find a read-only
516 * spte, even though the writable spte might be cached on a CPU's TLB.
518 * Returns true if the TLB needs to be flushed
520 static bool mmu_spte_update(u64 *sptep, u64 new_spte)
523 u64 old_spte = mmu_spte_update_no_track(sptep, new_spte);
525 if (!is_shadow_present_pte(old_spte))
529 * For the spte updated out of mmu-lock is safe, since
530 * we always atomically update it, see the comments in
531 * spte_has_volatile_bits().
533 if (is_mmu_writable_spte(old_spte) &&
534 !is_writable_pte(new_spte))
538 * Flush TLB when accessed/dirty states are changed in the page tables,
539 * to guarantee consistency between TLB and page tables.
542 if (is_accessed_spte(old_spte) && !is_accessed_spte(new_spte)) {
544 kvm_set_pfn_accessed(spte_to_pfn(old_spte));
547 if (is_dirty_spte(old_spte) && !is_dirty_spte(new_spte)) {
549 kvm_set_pfn_dirty(spte_to_pfn(old_spte));
556 * Rules for using mmu_spte_clear_track_bits:
557 * It sets the sptep from present to nonpresent, and track the
558 * state bits, it is used to clear the last level sptep.
559 * Returns the old PTE.
561 static int mmu_spte_clear_track_bits(struct kvm *kvm, u64 *sptep)
564 u64 old_spte = *sptep;
565 int level = sptep_to_sp(sptep)->role.level;
567 if (!is_shadow_present_pte(old_spte) ||
568 !spte_has_volatile_bits(old_spte))
569 __update_clear_spte_fast(sptep, 0ull);
571 old_spte = __update_clear_spte_slow(sptep, 0ull);
573 if (!is_shadow_present_pte(old_spte))
576 kvm_update_page_stats(kvm, level, -1);
578 pfn = spte_to_pfn(old_spte);
581 * KVM does not hold the refcount of the page used by
582 * kvm mmu, before reclaiming the page, we should
583 * unmap it from mmu first.
585 WARN_ON(!kvm_is_reserved_pfn(pfn) && !page_count(pfn_to_page(pfn)));
587 if (is_accessed_spte(old_spte))
588 kvm_set_pfn_accessed(pfn);
590 if (is_dirty_spte(old_spte))
591 kvm_set_pfn_dirty(pfn);
597 * Rules for using mmu_spte_clear_no_track:
598 * Directly clear spte without caring the state bits of sptep,
599 * it is used to set the upper level spte.
601 static void mmu_spte_clear_no_track(u64 *sptep)
603 __update_clear_spte_fast(sptep, 0ull);
606 static u64 mmu_spte_get_lockless(u64 *sptep)
608 return __get_spte_lockless(sptep);
611 /* Returns the Accessed status of the PTE and resets it at the same time. */
612 static bool mmu_spte_age(u64 *sptep)
614 u64 spte = mmu_spte_get_lockless(sptep);
616 if (!is_accessed_spte(spte))
619 if (spte_ad_enabled(spte)) {
620 clear_bit((ffs(shadow_accessed_mask) - 1),
621 (unsigned long *)sptep);
624 * Capture the dirty status of the page, so that it doesn't get
625 * lost when the SPTE is marked for access tracking.
627 if (is_writable_pte(spte))
628 kvm_set_pfn_dirty(spte_to_pfn(spte));
630 spte = mark_spte_for_access_track(spte);
631 mmu_spte_update_no_track(sptep, spte);
637 static void walk_shadow_page_lockless_begin(struct kvm_vcpu *vcpu)
639 if (is_tdp_mmu(vcpu->arch.mmu)) {
640 kvm_tdp_mmu_walk_lockless_begin();
643 * Prevent page table teardown by making any free-er wait during
644 * kvm_flush_remote_tlbs() IPI to all active vcpus.
649 * Make sure a following spte read is not reordered ahead of the write
652 smp_store_mb(vcpu->mode, READING_SHADOW_PAGE_TABLES);
656 static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu)
658 if (is_tdp_mmu(vcpu->arch.mmu)) {
659 kvm_tdp_mmu_walk_lockless_end();
662 * Make sure the write to vcpu->mode is not reordered in front of
663 * reads to sptes. If it does, kvm_mmu_commit_zap_page() can see us
664 * OUTSIDE_GUEST_MODE and proceed to free the shadow page table.
666 smp_store_release(&vcpu->mode, OUTSIDE_GUEST_MODE);
671 static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu, bool maybe_indirect)
675 /* 1 rmap, 1 parent PTE per level, and the prefetched rmaps. */
676 r = kvm_mmu_topup_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
677 1 + PT64_ROOT_MAX_LEVEL + PTE_PREFETCH_NUM);
680 r = kvm_mmu_topup_memory_cache(&vcpu->arch.mmu_shadow_page_cache,
681 PT64_ROOT_MAX_LEVEL);
684 if (maybe_indirect) {
685 r = kvm_mmu_topup_memory_cache(&vcpu->arch.mmu_gfn_array_cache,
686 PT64_ROOT_MAX_LEVEL);
690 return kvm_mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
691 PT64_ROOT_MAX_LEVEL);
694 static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
696 kvm_mmu_free_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache);
697 kvm_mmu_free_memory_cache(&vcpu->arch.mmu_shadow_page_cache);
698 kvm_mmu_free_memory_cache(&vcpu->arch.mmu_gfn_array_cache);
699 kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache);
702 static struct pte_list_desc *mmu_alloc_pte_list_desc(struct kvm_vcpu *vcpu)
704 return kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_list_desc_cache);
707 static void mmu_free_pte_list_desc(struct pte_list_desc *pte_list_desc)
709 kmem_cache_free(pte_list_desc_cache, pte_list_desc);
712 static gfn_t kvm_mmu_page_get_gfn(struct kvm_mmu_page *sp, int index)
714 if (sp->role.passthrough)
717 if (!sp->role.direct)
718 return sp->gfns[index];
720 return sp->gfn + (index << ((sp->role.level - 1) * PT64_LEVEL_BITS));
723 static void kvm_mmu_page_set_gfn(struct kvm_mmu_page *sp, int index, gfn_t gfn)
725 if (sp->role.passthrough) {
726 WARN_ON_ONCE(gfn != sp->gfn);
730 if (!sp->role.direct) {
731 sp->gfns[index] = gfn;
735 if (WARN_ON(gfn != kvm_mmu_page_get_gfn(sp, index)))
736 pr_err_ratelimited("gfn mismatch under direct page %llx "
737 "(expected %llx, got %llx)\n",
739 kvm_mmu_page_get_gfn(sp, index), gfn);
743 * Return the pointer to the large page information for a given gfn,
744 * handling slots that are not large page aligned.
746 static struct kvm_lpage_info *lpage_info_slot(gfn_t gfn,
747 const struct kvm_memory_slot *slot, int level)
751 idx = gfn_to_index(gfn, slot->base_gfn, level);
752 return &slot->arch.lpage_info[level - 2][idx];
755 static void update_gfn_disallow_lpage_count(const struct kvm_memory_slot *slot,
756 gfn_t gfn, int count)
758 struct kvm_lpage_info *linfo;
761 for (i = PG_LEVEL_2M; i <= KVM_MAX_HUGEPAGE_LEVEL; ++i) {
762 linfo = lpage_info_slot(gfn, slot, i);
763 linfo->disallow_lpage += count;
764 WARN_ON(linfo->disallow_lpage < 0);
768 void kvm_mmu_gfn_disallow_lpage(const struct kvm_memory_slot *slot, gfn_t gfn)
770 update_gfn_disallow_lpage_count(slot, gfn, 1);
773 void kvm_mmu_gfn_allow_lpage(const struct kvm_memory_slot *slot, gfn_t gfn)
775 update_gfn_disallow_lpage_count(slot, gfn, -1);
778 static void account_shadowed(struct kvm *kvm, struct kvm_mmu_page *sp)
780 struct kvm_memslots *slots;
781 struct kvm_memory_slot *slot;
784 kvm->arch.indirect_shadow_pages++;
786 slots = kvm_memslots_for_spte_role(kvm, sp->role);
787 slot = __gfn_to_memslot(slots, gfn);
789 /* the non-leaf shadow pages are keeping readonly. */
790 if (sp->role.level > PG_LEVEL_4K)
791 return kvm_slot_page_track_add_page(kvm, slot, gfn,
792 KVM_PAGE_TRACK_WRITE);
794 kvm_mmu_gfn_disallow_lpage(slot, gfn);
797 void account_huge_nx_page(struct kvm *kvm, struct kvm_mmu_page *sp)
799 if (sp->lpage_disallowed)
802 ++kvm->stat.nx_lpage_splits;
803 list_add_tail(&sp->lpage_disallowed_link,
804 &kvm->arch.lpage_disallowed_mmu_pages);
805 sp->lpage_disallowed = true;
808 static void unaccount_shadowed(struct kvm *kvm, struct kvm_mmu_page *sp)
810 struct kvm_memslots *slots;
811 struct kvm_memory_slot *slot;
814 kvm->arch.indirect_shadow_pages--;
816 slots = kvm_memslots_for_spte_role(kvm, sp->role);
817 slot = __gfn_to_memslot(slots, gfn);
818 if (sp->role.level > PG_LEVEL_4K)
819 return kvm_slot_page_track_remove_page(kvm, slot, gfn,
820 KVM_PAGE_TRACK_WRITE);
822 kvm_mmu_gfn_allow_lpage(slot, gfn);
825 void unaccount_huge_nx_page(struct kvm *kvm, struct kvm_mmu_page *sp)
827 --kvm->stat.nx_lpage_splits;
828 sp->lpage_disallowed = false;
829 list_del(&sp->lpage_disallowed_link);
832 static struct kvm_memory_slot *
833 gfn_to_memslot_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t gfn,
836 struct kvm_memory_slot *slot;
838 slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
839 if (!slot || slot->flags & KVM_MEMSLOT_INVALID)
841 if (no_dirty_log && kvm_slot_dirty_track_enabled(slot))
848 * About rmap_head encoding:
850 * If the bit zero of rmap_head->val is clear, then it points to the only spte
851 * in this rmap chain. Otherwise, (rmap_head->val & ~1) points to a struct
852 * pte_list_desc containing more mappings.
856 * Returns the number of pointers in the rmap chain, not counting the new one.
858 static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte,
859 struct kvm_rmap_head *rmap_head)
861 struct pte_list_desc *desc;
864 if (!rmap_head->val) {
865 rmap_printk("%p %llx 0->1\n", spte, *spte);
866 rmap_head->val = (unsigned long)spte;
867 } else if (!(rmap_head->val & 1)) {
868 rmap_printk("%p %llx 1->many\n", spte, *spte);
869 desc = mmu_alloc_pte_list_desc(vcpu);
870 desc->sptes[0] = (u64 *)rmap_head->val;
871 desc->sptes[1] = spte;
872 desc->spte_count = 2;
873 rmap_head->val = (unsigned long)desc | 1;
876 rmap_printk("%p %llx many->many\n", spte, *spte);
877 desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
878 while (desc->spte_count == PTE_LIST_EXT) {
879 count += PTE_LIST_EXT;
881 desc->more = mmu_alloc_pte_list_desc(vcpu);
883 desc->spte_count = 0;
888 count += desc->spte_count;
889 desc->sptes[desc->spte_count++] = spte;
895 pte_list_desc_remove_entry(struct kvm_rmap_head *rmap_head,
896 struct pte_list_desc *desc, int i,
897 struct pte_list_desc *prev_desc)
899 int j = desc->spte_count - 1;
901 desc->sptes[i] = desc->sptes[j];
902 desc->sptes[j] = NULL;
904 if (desc->spte_count)
906 if (!prev_desc && !desc->more)
910 prev_desc->more = desc->more;
912 rmap_head->val = (unsigned long)desc->more | 1;
913 mmu_free_pte_list_desc(desc);
916 static void __pte_list_remove(u64 *spte, struct kvm_rmap_head *rmap_head)
918 struct pte_list_desc *desc;
919 struct pte_list_desc *prev_desc;
922 if (!rmap_head->val) {
923 pr_err("%s: %p 0->BUG\n", __func__, spte);
925 } else if (!(rmap_head->val & 1)) {
926 rmap_printk("%p 1->0\n", spte);
927 if ((u64 *)rmap_head->val != spte) {
928 pr_err("%s: %p 1->BUG\n", __func__, spte);
933 rmap_printk("%p many->many\n", spte);
934 desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
937 for (i = 0; i < desc->spte_count; ++i) {
938 if (desc->sptes[i] == spte) {
939 pte_list_desc_remove_entry(rmap_head,
947 pr_err("%s: %p many->many\n", __func__, spte);
952 static void pte_list_remove(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
955 mmu_spte_clear_track_bits(kvm, sptep);
956 __pte_list_remove(sptep, rmap_head);
959 /* Return true if rmap existed, false otherwise */
960 static bool pte_list_destroy(struct kvm *kvm, struct kvm_rmap_head *rmap_head)
962 struct pte_list_desc *desc, *next;
968 if (!(rmap_head->val & 1)) {
969 mmu_spte_clear_track_bits(kvm, (u64 *)rmap_head->val);
973 desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
975 for (; desc; desc = next) {
976 for (i = 0; i < desc->spte_count; i++)
977 mmu_spte_clear_track_bits(kvm, desc->sptes[i]);
979 mmu_free_pte_list_desc(desc);
982 /* rmap_head is meaningless now, remember to reset it */
987 unsigned int pte_list_count(struct kvm_rmap_head *rmap_head)
989 struct pte_list_desc *desc;
990 unsigned int count = 0;
994 else if (!(rmap_head->val & 1))
997 desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
1000 count += desc->spte_count;
1007 static struct kvm_rmap_head *gfn_to_rmap(gfn_t gfn, int level,
1008 const struct kvm_memory_slot *slot)
1012 idx = gfn_to_index(gfn, slot->base_gfn, level);
1013 return &slot->arch.rmap[level - PG_LEVEL_4K][idx];
1016 static bool rmap_can_add(struct kvm_vcpu *vcpu)
1018 struct kvm_mmu_memory_cache *mc;
1020 mc = &vcpu->arch.mmu_pte_list_desc_cache;
1021 return kvm_mmu_memory_cache_nr_free_objects(mc);
1024 static void rmap_remove(struct kvm *kvm, u64 *spte)
1026 struct kvm_memslots *slots;
1027 struct kvm_memory_slot *slot;
1028 struct kvm_mmu_page *sp;
1030 struct kvm_rmap_head *rmap_head;
1032 sp = sptep_to_sp(spte);
1033 gfn = kvm_mmu_page_get_gfn(sp, spte - sp->spt);
1036 * Unlike rmap_add, rmap_remove does not run in the context of a vCPU
1037 * so we have to determine which memslots to use based on context
1038 * information in sp->role.
1040 slots = kvm_memslots_for_spte_role(kvm, sp->role);
1042 slot = __gfn_to_memslot(slots, gfn);
1043 rmap_head = gfn_to_rmap(gfn, sp->role.level, slot);
1045 __pte_list_remove(spte, rmap_head);
1049 * Used by the following functions to iterate through the sptes linked by a
1050 * rmap. All fields are private and not assumed to be used outside.
1052 struct rmap_iterator {
1053 /* private fields */
1054 struct pte_list_desc *desc; /* holds the sptep if not NULL */
1055 int pos; /* index of the sptep */
1059 * Iteration must be started by this function. This should also be used after
1060 * removing/dropping sptes from the rmap link because in such cases the
1061 * information in the iterator may not be valid.
1063 * Returns sptep if found, NULL otherwise.
1065 static u64 *rmap_get_first(struct kvm_rmap_head *rmap_head,
1066 struct rmap_iterator *iter)
1070 if (!rmap_head->val)
1073 if (!(rmap_head->val & 1)) {
1075 sptep = (u64 *)rmap_head->val;
1079 iter->desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
1081 sptep = iter->desc->sptes[iter->pos];
1083 BUG_ON(!is_shadow_present_pte(*sptep));
1088 * Must be used with a valid iterator: e.g. after rmap_get_first().
1090 * Returns sptep if found, NULL otherwise.
1092 static u64 *rmap_get_next(struct rmap_iterator *iter)
1097 if (iter->pos < PTE_LIST_EXT - 1) {
1099 sptep = iter->desc->sptes[iter->pos];
1104 iter->desc = iter->desc->more;
1108 /* desc->sptes[0] cannot be NULL */
1109 sptep = iter->desc->sptes[iter->pos];
1116 BUG_ON(!is_shadow_present_pte(*sptep));
1120 #define for_each_rmap_spte(_rmap_head_, _iter_, _spte_) \
1121 for (_spte_ = rmap_get_first(_rmap_head_, _iter_); \
1122 _spte_; _spte_ = rmap_get_next(_iter_))
1124 static void drop_spte(struct kvm *kvm, u64 *sptep)
1126 u64 old_spte = mmu_spte_clear_track_bits(kvm, sptep);
1128 if (is_shadow_present_pte(old_spte))
1129 rmap_remove(kvm, sptep);
1133 static bool __drop_large_spte(struct kvm *kvm, u64 *sptep)
1135 if (is_large_pte(*sptep)) {
1136 WARN_ON(sptep_to_sp(sptep)->role.level == PG_LEVEL_4K);
1137 drop_spte(kvm, sptep);
1144 static void drop_large_spte(struct kvm_vcpu *vcpu, u64 *sptep)
1146 if (__drop_large_spte(vcpu->kvm, sptep)) {
1147 struct kvm_mmu_page *sp = sptep_to_sp(sptep);
1149 kvm_flush_remote_tlbs_with_address(vcpu->kvm, sp->gfn,
1150 KVM_PAGES_PER_HPAGE(sp->role.level));
1155 * Write-protect on the specified @sptep, @pt_protect indicates whether
1156 * spte write-protection is caused by protecting shadow page table.
1158 * Note: write protection is difference between dirty logging and spte
1160 * - for dirty logging, the spte can be set to writable at anytime if
1161 * its dirty bitmap is properly set.
1162 * - for spte protection, the spte can be writable only after unsync-ing
1165 * Return true if tlb need be flushed.
1167 static bool spte_write_protect(u64 *sptep, bool pt_protect)
1171 if (!is_writable_pte(spte) &&
1172 !(pt_protect && is_mmu_writable_spte(spte)))
1175 rmap_printk("spte %p %llx\n", sptep, *sptep);
1178 spte &= ~shadow_mmu_writable_mask;
1179 spte = spte & ~PT_WRITABLE_MASK;
1181 return mmu_spte_update(sptep, spte);
1184 static bool rmap_write_protect(struct kvm_rmap_head *rmap_head,
1188 struct rmap_iterator iter;
1191 for_each_rmap_spte(rmap_head, &iter, sptep)
1192 flush |= spte_write_protect(sptep, pt_protect);
1197 static bool spte_clear_dirty(u64 *sptep)
1201 rmap_printk("spte %p %llx\n", sptep, *sptep);
1203 MMU_WARN_ON(!spte_ad_enabled(spte));
1204 spte &= ~shadow_dirty_mask;
1205 return mmu_spte_update(sptep, spte);
1208 static bool spte_wrprot_for_clear_dirty(u64 *sptep)
1210 bool was_writable = test_and_clear_bit(PT_WRITABLE_SHIFT,
1211 (unsigned long *)sptep);
1212 if (was_writable && !spte_ad_enabled(*sptep))
1213 kvm_set_pfn_dirty(spte_to_pfn(*sptep));
1215 return was_writable;
1219 * Gets the GFN ready for another round of dirty logging by clearing the
1220 * - D bit on ad-enabled SPTEs, and
1221 * - W bit on ad-disabled SPTEs.
1222 * Returns true iff any D or W bits were cleared.
1224 static bool __rmap_clear_dirty(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
1225 const struct kvm_memory_slot *slot)
1228 struct rmap_iterator iter;
1231 for_each_rmap_spte(rmap_head, &iter, sptep)
1232 if (spte_ad_need_write_protect(*sptep))
1233 flush |= spte_wrprot_for_clear_dirty(sptep);
1235 flush |= spte_clear_dirty(sptep);
1241 * kvm_mmu_write_protect_pt_masked - write protect selected PT level pages
1242 * @kvm: kvm instance
1243 * @slot: slot to protect
1244 * @gfn_offset: start of the BITS_PER_LONG pages we care about
1245 * @mask: indicates which pages we should protect
1247 * Used when we do not need to care about huge page mappings.
1249 static void kvm_mmu_write_protect_pt_masked(struct kvm *kvm,
1250 struct kvm_memory_slot *slot,
1251 gfn_t gfn_offset, unsigned long mask)
1253 struct kvm_rmap_head *rmap_head;
1255 if (is_tdp_mmu_enabled(kvm))
1256 kvm_tdp_mmu_clear_dirty_pt_masked(kvm, slot,
1257 slot->base_gfn + gfn_offset, mask, true);
1259 if (!kvm_memslots_have_rmaps(kvm))
1263 rmap_head = gfn_to_rmap(slot->base_gfn + gfn_offset + __ffs(mask),
1265 rmap_write_protect(rmap_head, false);
1267 /* clear the first set bit */
1273 * kvm_mmu_clear_dirty_pt_masked - clear MMU D-bit for PT level pages, or write
1274 * protect the page if the D-bit isn't supported.
1275 * @kvm: kvm instance
1276 * @slot: slot to clear D-bit
1277 * @gfn_offset: start of the BITS_PER_LONG pages we care about
1278 * @mask: indicates which pages we should clear D-bit
1280 * Used for PML to re-log the dirty GPAs after userspace querying dirty_bitmap.
1282 static void kvm_mmu_clear_dirty_pt_masked(struct kvm *kvm,
1283 struct kvm_memory_slot *slot,
1284 gfn_t gfn_offset, unsigned long mask)
1286 struct kvm_rmap_head *rmap_head;
1288 if (is_tdp_mmu_enabled(kvm))
1289 kvm_tdp_mmu_clear_dirty_pt_masked(kvm, slot,
1290 slot->base_gfn + gfn_offset, mask, false);
1292 if (!kvm_memslots_have_rmaps(kvm))
1296 rmap_head = gfn_to_rmap(slot->base_gfn + gfn_offset + __ffs(mask),
1298 __rmap_clear_dirty(kvm, rmap_head, slot);
1300 /* clear the first set bit */
1306 * kvm_arch_mmu_enable_log_dirty_pt_masked - enable dirty logging for selected
1309 * It calls kvm_mmu_write_protect_pt_masked to write protect selected pages to
1310 * enable dirty logging for them.
1312 * We need to care about huge page mappings: e.g. during dirty logging we may
1313 * have such mappings.
1315 void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
1316 struct kvm_memory_slot *slot,
1317 gfn_t gfn_offset, unsigned long mask)
1320 * Huge pages are NOT write protected when we start dirty logging in
1321 * initially-all-set mode; must write protect them here so that they
1322 * are split to 4K on the first write.
1324 * The gfn_offset is guaranteed to be aligned to 64, but the base_gfn
1325 * of memslot has no such restriction, so the range can cross two large
1328 if (kvm_dirty_log_manual_protect_and_init_set(kvm)) {
1329 gfn_t start = slot->base_gfn + gfn_offset + __ffs(mask);
1330 gfn_t end = slot->base_gfn + gfn_offset + __fls(mask);
1332 if (READ_ONCE(eager_page_split))
1333 kvm_mmu_try_split_huge_pages(kvm, slot, start, end, PG_LEVEL_4K);
1335 kvm_mmu_slot_gfn_write_protect(kvm, slot, start, PG_LEVEL_2M);
1337 /* Cross two large pages? */
1338 if (ALIGN(start << PAGE_SHIFT, PMD_SIZE) !=
1339 ALIGN(end << PAGE_SHIFT, PMD_SIZE))
1340 kvm_mmu_slot_gfn_write_protect(kvm, slot, end,
1344 /* Now handle 4K PTEs. */
1345 if (kvm_x86_ops.cpu_dirty_log_size)
1346 kvm_mmu_clear_dirty_pt_masked(kvm, slot, gfn_offset, mask);
1348 kvm_mmu_write_protect_pt_masked(kvm, slot, gfn_offset, mask);
1351 int kvm_cpu_dirty_log_size(void)
1353 return kvm_x86_ops.cpu_dirty_log_size;
1356 bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
1357 struct kvm_memory_slot *slot, u64 gfn,
1360 struct kvm_rmap_head *rmap_head;
1362 bool write_protected = false;
1364 if (kvm_memslots_have_rmaps(kvm)) {
1365 for (i = min_level; i <= KVM_MAX_HUGEPAGE_LEVEL; ++i) {
1366 rmap_head = gfn_to_rmap(gfn, i, slot);
1367 write_protected |= rmap_write_protect(rmap_head, true);
1371 if (is_tdp_mmu_enabled(kvm))
1373 kvm_tdp_mmu_write_protect_gfn(kvm, slot, gfn, min_level);
1375 return write_protected;
1378 static bool kvm_vcpu_write_protect_gfn(struct kvm_vcpu *vcpu, u64 gfn)
1380 struct kvm_memory_slot *slot;
1382 slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
1383 return kvm_mmu_slot_gfn_write_protect(vcpu->kvm, slot, gfn, PG_LEVEL_4K);
1386 static bool kvm_zap_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
1387 const struct kvm_memory_slot *slot)
1389 return pte_list_destroy(kvm, rmap_head);
1392 static bool kvm_unmap_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
1393 struct kvm_memory_slot *slot, gfn_t gfn, int level,
1396 return kvm_zap_rmapp(kvm, rmap_head, slot);
1399 static bool kvm_set_pte_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
1400 struct kvm_memory_slot *slot, gfn_t gfn, int level,
1404 struct rmap_iterator iter;
1405 bool need_flush = false;
1409 WARN_ON(pte_huge(pte));
1410 new_pfn = pte_pfn(pte);
1413 for_each_rmap_spte(rmap_head, &iter, sptep) {
1414 rmap_printk("spte %p %llx gfn %llx (%d)\n",
1415 sptep, *sptep, gfn, level);
1419 if (pte_write(pte)) {
1420 pte_list_remove(kvm, rmap_head, sptep);
1423 new_spte = kvm_mmu_changed_pte_notifier_make_spte(
1426 mmu_spte_clear_track_bits(kvm, sptep);
1427 mmu_spte_set(sptep, new_spte);
1431 if (need_flush && kvm_available_flush_tlb_with_range()) {
1432 kvm_flush_remote_tlbs_with_address(kvm, gfn, 1);
1439 struct slot_rmap_walk_iterator {
1441 const struct kvm_memory_slot *slot;
1447 /* output fields. */
1449 struct kvm_rmap_head *rmap;
1452 /* private field. */
1453 struct kvm_rmap_head *end_rmap;
1457 rmap_walk_init_level(struct slot_rmap_walk_iterator *iterator, int level)
1459 iterator->level = level;
1460 iterator->gfn = iterator->start_gfn;
1461 iterator->rmap = gfn_to_rmap(iterator->gfn, level, iterator->slot);
1462 iterator->end_rmap = gfn_to_rmap(iterator->end_gfn, level, iterator->slot);
1466 slot_rmap_walk_init(struct slot_rmap_walk_iterator *iterator,
1467 const struct kvm_memory_slot *slot, int start_level,
1468 int end_level, gfn_t start_gfn, gfn_t end_gfn)
1470 iterator->slot = slot;
1471 iterator->start_level = start_level;
1472 iterator->end_level = end_level;
1473 iterator->start_gfn = start_gfn;
1474 iterator->end_gfn = end_gfn;
1476 rmap_walk_init_level(iterator, iterator->start_level);
1479 static bool slot_rmap_walk_okay(struct slot_rmap_walk_iterator *iterator)
1481 return !!iterator->rmap;
1484 static void slot_rmap_walk_next(struct slot_rmap_walk_iterator *iterator)
1486 while (++iterator->rmap <= iterator->end_rmap) {
1487 iterator->gfn += (1UL << KVM_HPAGE_GFN_SHIFT(iterator->level));
1489 if (iterator->rmap->val)
1493 if (++iterator->level > iterator->end_level) {
1494 iterator->rmap = NULL;
1498 rmap_walk_init_level(iterator, iterator->level);
1501 #define for_each_slot_rmap_range(_slot_, _start_level_, _end_level_, \
1502 _start_gfn, _end_gfn, _iter_) \
1503 for (slot_rmap_walk_init(_iter_, _slot_, _start_level_, \
1504 _end_level_, _start_gfn, _end_gfn); \
1505 slot_rmap_walk_okay(_iter_); \
1506 slot_rmap_walk_next(_iter_))
1508 typedef bool (*rmap_handler_t)(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
1509 struct kvm_memory_slot *slot, gfn_t gfn,
1510 int level, pte_t pte);
1512 static __always_inline bool kvm_handle_gfn_range(struct kvm *kvm,
1513 struct kvm_gfn_range *range,
1514 rmap_handler_t handler)
1516 struct slot_rmap_walk_iterator iterator;
1519 for_each_slot_rmap_range(range->slot, PG_LEVEL_4K, KVM_MAX_HUGEPAGE_LEVEL,
1520 range->start, range->end - 1, &iterator)
1521 ret |= handler(kvm, iterator.rmap, range->slot, iterator.gfn,
1522 iterator.level, range->pte);
1527 bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
1531 if (kvm_memslots_have_rmaps(kvm))
1532 flush = kvm_handle_gfn_range(kvm, range, kvm_unmap_rmapp);
1534 if (is_tdp_mmu_enabled(kvm))
1535 flush = kvm_tdp_mmu_unmap_gfn_range(kvm, range, flush);
1540 bool kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
1544 if (kvm_memslots_have_rmaps(kvm))
1545 flush = kvm_handle_gfn_range(kvm, range, kvm_set_pte_rmapp);
1547 if (is_tdp_mmu_enabled(kvm))
1548 flush |= kvm_tdp_mmu_set_spte_gfn(kvm, range);
1553 static bool kvm_age_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
1554 struct kvm_memory_slot *slot, gfn_t gfn, int level,
1558 struct rmap_iterator iter;
1561 for_each_rmap_spte(rmap_head, &iter, sptep)
1562 young |= mmu_spte_age(sptep);
1567 static bool kvm_test_age_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
1568 struct kvm_memory_slot *slot, gfn_t gfn,
1569 int level, pte_t unused)
1572 struct rmap_iterator iter;
1574 for_each_rmap_spte(rmap_head, &iter, sptep)
1575 if (is_accessed_spte(*sptep))
1580 #define RMAP_RECYCLE_THRESHOLD 1000
1582 static void rmap_add(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot,
1583 u64 *spte, gfn_t gfn)
1585 struct kvm_mmu_page *sp;
1586 struct kvm_rmap_head *rmap_head;
1589 sp = sptep_to_sp(spte);
1590 kvm_mmu_page_set_gfn(sp, spte - sp->spt, gfn);
1591 rmap_head = gfn_to_rmap(gfn, sp->role.level, slot);
1592 rmap_count = pte_list_add(vcpu, spte, rmap_head);
1594 if (rmap_count > RMAP_RECYCLE_THRESHOLD) {
1595 kvm_unmap_rmapp(vcpu->kvm, rmap_head, NULL, gfn, sp->role.level, __pte(0));
1596 kvm_flush_remote_tlbs_with_address(
1597 vcpu->kvm, sp->gfn, KVM_PAGES_PER_HPAGE(sp->role.level));
1601 bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
1605 if (kvm_memslots_have_rmaps(kvm))
1606 young = kvm_handle_gfn_range(kvm, range, kvm_age_rmapp);
1608 if (is_tdp_mmu_enabled(kvm))
1609 young |= kvm_tdp_mmu_age_gfn_range(kvm, range);
1614 bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
1618 if (kvm_memslots_have_rmaps(kvm))
1619 young = kvm_handle_gfn_range(kvm, range, kvm_test_age_rmapp);
1621 if (is_tdp_mmu_enabled(kvm))
1622 young |= kvm_tdp_mmu_test_age_gfn(kvm, range);
1628 static int is_empty_shadow_page(u64 *spt)
1633 for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
1634 if (is_shadow_present_pte(*pos)) {
1635 printk(KERN_ERR "%s: %p %llx\n", __func__,
1644 * This value is the sum of all of the kvm instances's
1645 * kvm->arch.n_used_mmu_pages values. We need a global,
1646 * aggregate version in order to make the slab shrinker
1649 static inline void kvm_mod_used_mmu_pages(struct kvm *kvm, long nr)
1651 kvm->arch.n_used_mmu_pages += nr;
1652 percpu_counter_add(&kvm_total_used_mmu_pages, nr);
1655 static void kvm_mmu_free_page(struct kvm_mmu_page *sp)
1657 MMU_WARN_ON(!is_empty_shadow_page(sp->spt));
1658 hlist_del(&sp->hash_link);
1659 list_del(&sp->link);
1660 free_page((unsigned long)sp->spt);
1661 if (!sp->role.direct)
1662 free_page((unsigned long)sp->gfns);
1663 kmem_cache_free(mmu_page_header_cache, sp);
1666 static unsigned kvm_page_table_hashfn(gfn_t gfn)
1668 return hash_64(gfn, KVM_MMU_HASH_SHIFT);
1671 static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
1672 struct kvm_mmu_page *sp, u64 *parent_pte)
1677 pte_list_add(vcpu, parent_pte, &sp->parent_ptes);
1680 static void mmu_page_remove_parent_pte(struct kvm_mmu_page *sp,
1683 __pte_list_remove(parent_pte, &sp->parent_ptes);
1686 static void drop_parent_pte(struct kvm_mmu_page *sp,
1689 mmu_page_remove_parent_pte(sp, parent_pte);
1690 mmu_spte_clear_no_track(parent_pte);
1693 static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, int direct)
1695 struct kvm_mmu_page *sp;
1697 sp = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache);
1698 sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache);
1700 sp->gfns = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_gfn_array_cache);
1701 set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
1704 * active_mmu_pages must be a FIFO list, as kvm_zap_obsolete_pages()
1705 * depends on valid pages being added to the head of the list. See
1706 * comments in kvm_zap_obsolete_pages().
1708 sp->mmu_valid_gen = vcpu->kvm->arch.mmu_valid_gen;
1709 list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
1710 kvm_mod_used_mmu_pages(vcpu->kvm, +1);
1714 static void mark_unsync(u64 *spte);
1715 static void kvm_mmu_mark_parents_unsync(struct kvm_mmu_page *sp)
1718 struct rmap_iterator iter;
1720 for_each_rmap_spte(&sp->parent_ptes, &iter, sptep) {
1725 static void mark_unsync(u64 *spte)
1727 struct kvm_mmu_page *sp;
1730 sp = sptep_to_sp(spte);
1731 index = spte - sp->spt;
1732 if (__test_and_set_bit(index, sp->unsync_child_bitmap))
1734 if (sp->unsync_children++)
1736 kvm_mmu_mark_parents_unsync(sp);
1739 static int nonpaging_sync_page(struct kvm_vcpu *vcpu,
1740 struct kvm_mmu_page *sp)
1745 #define KVM_PAGE_ARRAY_NR 16
1747 struct kvm_mmu_pages {
1748 struct mmu_page_and_offset {
1749 struct kvm_mmu_page *sp;
1751 } page[KVM_PAGE_ARRAY_NR];
1755 static int mmu_pages_add(struct kvm_mmu_pages *pvec, struct kvm_mmu_page *sp,
1761 for (i=0; i < pvec->nr; i++)
1762 if (pvec->page[i].sp == sp)
1765 pvec->page[pvec->nr].sp = sp;
1766 pvec->page[pvec->nr].idx = idx;
1768 return (pvec->nr == KVM_PAGE_ARRAY_NR);
1771 static inline void clear_unsync_child_bit(struct kvm_mmu_page *sp, int idx)
1773 --sp->unsync_children;
1774 WARN_ON((int)sp->unsync_children < 0);
1775 __clear_bit(idx, sp->unsync_child_bitmap);
1778 static int __mmu_unsync_walk(struct kvm_mmu_page *sp,
1779 struct kvm_mmu_pages *pvec)
1781 int i, ret, nr_unsync_leaf = 0;
1783 for_each_set_bit(i, sp->unsync_child_bitmap, 512) {
1784 struct kvm_mmu_page *child;
1785 u64 ent = sp->spt[i];
1787 if (!is_shadow_present_pte(ent) || is_large_pte(ent)) {
1788 clear_unsync_child_bit(sp, i);
1792 child = to_shadow_page(ent & PT64_BASE_ADDR_MASK);
1794 if (child->unsync_children) {
1795 if (mmu_pages_add(pvec, child, i))
1798 ret = __mmu_unsync_walk(child, pvec);
1800 clear_unsync_child_bit(sp, i);
1802 } else if (ret > 0) {
1803 nr_unsync_leaf += ret;
1806 } else if (child->unsync) {
1808 if (mmu_pages_add(pvec, child, i))
1811 clear_unsync_child_bit(sp, i);
1814 return nr_unsync_leaf;
1817 #define INVALID_INDEX (-1)
1819 static int mmu_unsync_walk(struct kvm_mmu_page *sp,
1820 struct kvm_mmu_pages *pvec)
1823 if (!sp->unsync_children)
1826 mmu_pages_add(pvec, sp, INVALID_INDEX);
1827 return __mmu_unsync_walk(sp, pvec);
1830 static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
1832 WARN_ON(!sp->unsync);
1833 trace_kvm_mmu_sync_page(sp);
1835 --kvm->stat.mmu_unsync;
1838 static bool kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
1839 struct list_head *invalid_list);
1840 static void kvm_mmu_commit_zap_page(struct kvm *kvm,
1841 struct list_head *invalid_list);
1843 static bool sp_has_gptes(struct kvm_mmu_page *sp)
1845 if (sp->role.direct)
1848 if (sp->role.passthrough)
1854 #define for_each_valid_sp(_kvm, _sp, _list) \
1855 hlist_for_each_entry(_sp, _list, hash_link) \
1856 if (is_obsolete_sp((_kvm), (_sp))) { \
1859 #define for_each_gfn_valid_sp_with_gptes(_kvm, _sp, _gfn) \
1860 for_each_valid_sp(_kvm, _sp, \
1861 &(_kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(_gfn)]) \
1862 if ((_sp)->gfn != (_gfn) || !sp_has_gptes(_sp)) {} else
1864 static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
1865 struct list_head *invalid_list)
1867 int ret = vcpu->arch.mmu->sync_page(vcpu, sp);
1870 kvm_mmu_prepare_zap_page(vcpu->kvm, sp, invalid_list);
1874 static bool kvm_mmu_remote_flush_or_zap(struct kvm *kvm,
1875 struct list_head *invalid_list,
1878 if (!remote_flush && list_empty(invalid_list))
1881 if (!list_empty(invalid_list))
1882 kvm_mmu_commit_zap_page(kvm, invalid_list);
1884 kvm_flush_remote_tlbs(kvm);
1888 static bool is_obsolete_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
1890 if (sp->role.invalid)
1893 /* TDP MMU pages due not use the MMU generation. */
1894 return !sp->tdp_mmu_page &&
1895 unlikely(sp->mmu_valid_gen != kvm->arch.mmu_valid_gen);
1898 struct mmu_page_path {
1899 struct kvm_mmu_page *parent[PT64_ROOT_MAX_LEVEL];
1900 unsigned int idx[PT64_ROOT_MAX_LEVEL];
1903 #define for_each_sp(pvec, sp, parents, i) \
1904 for (i = mmu_pages_first(&pvec, &parents); \
1905 i < pvec.nr && ({ sp = pvec.page[i].sp; 1;}); \
1906 i = mmu_pages_next(&pvec, &parents, i))
1908 static int mmu_pages_next(struct kvm_mmu_pages *pvec,
1909 struct mmu_page_path *parents,
1914 for (n = i+1; n < pvec->nr; n++) {
1915 struct kvm_mmu_page *sp = pvec->page[n].sp;
1916 unsigned idx = pvec->page[n].idx;
1917 int level = sp->role.level;
1919 parents->idx[level-1] = idx;
1920 if (level == PG_LEVEL_4K)
1923 parents->parent[level-2] = sp;
1929 static int mmu_pages_first(struct kvm_mmu_pages *pvec,
1930 struct mmu_page_path *parents)
1932 struct kvm_mmu_page *sp;
1938 WARN_ON(pvec->page[0].idx != INVALID_INDEX);
1940 sp = pvec->page[0].sp;
1941 level = sp->role.level;
1942 WARN_ON(level == PG_LEVEL_4K);
1944 parents->parent[level-2] = sp;
1946 /* Also set up a sentinel. Further entries in pvec are all
1947 * children of sp, so this element is never overwritten.
1949 parents->parent[level-1] = NULL;
1950 return mmu_pages_next(pvec, parents, 0);
1953 static void mmu_pages_clear_parents(struct mmu_page_path *parents)
1955 struct kvm_mmu_page *sp;
1956 unsigned int level = 0;
1959 unsigned int idx = parents->idx[level];
1960 sp = parents->parent[level];
1964 WARN_ON(idx == INVALID_INDEX);
1965 clear_unsync_child_bit(sp, idx);
1967 } while (!sp->unsync_children);
1970 static int mmu_sync_children(struct kvm_vcpu *vcpu,
1971 struct kvm_mmu_page *parent, bool can_yield)
1974 struct kvm_mmu_page *sp;
1975 struct mmu_page_path parents;
1976 struct kvm_mmu_pages pages;
1977 LIST_HEAD(invalid_list);
1980 while (mmu_unsync_walk(parent, &pages)) {
1981 bool protected = false;
1983 for_each_sp(pages, sp, parents, i)
1984 protected |= kvm_vcpu_write_protect_gfn(vcpu, sp->gfn);
1987 kvm_mmu_remote_flush_or_zap(vcpu->kvm, &invalid_list, true);
1991 for_each_sp(pages, sp, parents, i) {
1992 kvm_unlink_unsync_page(vcpu->kvm, sp);
1993 flush |= kvm_sync_page(vcpu, sp, &invalid_list) > 0;
1994 mmu_pages_clear_parents(&parents);
1996 if (need_resched() || rwlock_needbreak(&vcpu->kvm->mmu_lock)) {
1997 kvm_mmu_remote_flush_or_zap(vcpu->kvm, &invalid_list, flush);
1999 kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);
2003 cond_resched_rwlock_write(&vcpu->kvm->mmu_lock);
2008 kvm_mmu_remote_flush_or_zap(vcpu->kvm, &invalid_list, flush);
2012 static void __clear_sp_write_flooding_count(struct kvm_mmu_page *sp)
2014 atomic_set(&sp->write_flooding_count, 0);
2017 static void clear_sp_write_flooding_count(u64 *spte)
2019 __clear_sp_write_flooding_count(sptep_to_sp(spte));
2022 static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
2027 unsigned int access)
2029 bool direct_mmu = vcpu->arch.mmu->root_role.direct;
2030 union kvm_mmu_page_role role;
2031 struct hlist_head *sp_list;
2033 struct kvm_mmu_page *sp;
2036 LIST_HEAD(invalid_list);
2038 role = vcpu->arch.mmu->root_role;
2040 role.direct = direct;
2041 role.access = access;
2042 if (role.has_4_byte_gpte) {
2043 quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
2044 quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
2045 role.quadrant = quadrant;
2047 if (level <= vcpu->arch.mmu->cpu_role.base.level)
2048 role.passthrough = 0;
2050 sp_list = &vcpu->kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)];
2051 for_each_valid_sp(vcpu->kvm, sp, sp_list) {
2052 if (sp->gfn != gfn) {
2057 if (sp->role.word != role.word) {
2059 * If the guest is creating an upper-level page, zap
2060 * unsync pages for the same gfn. While it's possible
2061 * the guest is using recursive page tables, in all
2062 * likelihood the guest has stopped using the unsync
2063 * page and is installing a completely unrelated page.
2064 * Unsync pages must not be left as is, because the new
2065 * upper-level page will be write-protected.
2067 if (level > PG_LEVEL_4K && sp->unsync)
2068 kvm_mmu_prepare_zap_page(vcpu->kvm, sp,
2074 goto trace_get_page;
2078 * The page is good, but is stale. kvm_sync_page does
2079 * get the latest guest state, but (unlike mmu_unsync_children)
2080 * it doesn't write-protect the page or mark it synchronized!
2081 * This way the validity of the mapping is ensured, but the
2082 * overhead of write protection is not incurred until the
2083 * guest invalidates the TLB mapping. This allows multiple
2084 * SPs for a single gfn to be unsync.
2086 * If the sync fails, the page is zapped. If so, break
2087 * in order to rebuild it.
2089 ret = kvm_sync_page(vcpu, sp, &invalid_list);
2093 WARN_ON(!list_empty(&invalid_list));
2095 kvm_flush_remote_tlbs(vcpu->kvm);
2098 __clear_sp_write_flooding_count(sp);
2101 trace_kvm_mmu_get_page(sp, false);
2105 ++vcpu->kvm->stat.mmu_cache_miss;
2107 sp = kvm_mmu_alloc_page(vcpu, direct);
2111 hlist_add_head(&sp->hash_link, sp_list);
2112 if (sp_has_gptes(sp)) {
2113 account_shadowed(vcpu->kvm, sp);
2114 if (level == PG_LEVEL_4K && kvm_vcpu_write_protect_gfn(vcpu, gfn))
2115 kvm_flush_remote_tlbs_with_address(vcpu->kvm, gfn, 1);
2117 trace_kvm_mmu_get_page(sp, true);
2119 kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
2121 if (collisions > vcpu->kvm->stat.max_mmu_page_hash_collisions)
2122 vcpu->kvm->stat.max_mmu_page_hash_collisions = collisions;
2126 static void shadow_walk_init_using_root(struct kvm_shadow_walk_iterator *iterator,
2127 struct kvm_vcpu *vcpu, hpa_t root,
2130 iterator->addr = addr;
2131 iterator->shadow_addr = root;
2132 iterator->level = vcpu->arch.mmu->root_role.level;
2134 if (iterator->level >= PT64_ROOT_4LEVEL &&
2135 vcpu->arch.mmu->cpu_role.base.level < PT64_ROOT_4LEVEL &&
2136 !vcpu->arch.mmu->root_role.direct)
2137 iterator->level = PT32E_ROOT_LEVEL;
2139 if (iterator->level == PT32E_ROOT_LEVEL) {
2141 * prev_root is currently only used for 64-bit hosts. So only
2142 * the active root_hpa is valid here.
2144 BUG_ON(root != vcpu->arch.mmu->root.hpa);
2146 iterator->shadow_addr
2147 = vcpu->arch.mmu->pae_root[(addr >> 30) & 3];
2148 iterator->shadow_addr &= PT64_BASE_ADDR_MASK;
2150 if (!iterator->shadow_addr)
2151 iterator->level = 0;
2155 static void shadow_walk_init(struct kvm_shadow_walk_iterator *iterator,
2156 struct kvm_vcpu *vcpu, u64 addr)
2158 shadow_walk_init_using_root(iterator, vcpu, vcpu->arch.mmu->root.hpa,
2162 static bool shadow_walk_okay(struct kvm_shadow_walk_iterator *iterator)
2164 if (iterator->level < PG_LEVEL_4K)
2167 iterator->index = SHADOW_PT_INDEX(iterator->addr, iterator->level);
2168 iterator->sptep = ((u64 *)__va(iterator->shadow_addr)) + iterator->index;
2172 static void __shadow_walk_next(struct kvm_shadow_walk_iterator *iterator,
2175 if (!is_shadow_present_pte(spte) || is_last_spte(spte, iterator->level)) {
2176 iterator->level = 0;
2180 iterator->shadow_addr = spte & PT64_BASE_ADDR_MASK;
2184 static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator)
2186 __shadow_walk_next(iterator, *iterator->sptep);
2189 static void link_shadow_page(struct kvm_vcpu *vcpu, u64 *sptep,
2190 struct kvm_mmu_page *sp)
2194 BUILD_BUG_ON(VMX_EPT_WRITABLE_MASK != PT_WRITABLE_MASK);
2196 spte = make_nonleaf_spte(sp->spt, sp_ad_disabled(sp));
2198 mmu_spte_set(sptep, spte);
2200 mmu_page_add_parent_pte(vcpu, sp, sptep);
2202 if (sp->unsync_children || sp->unsync)
2206 static void validate_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep,
2207 unsigned direct_access)
2209 if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep)) {
2210 struct kvm_mmu_page *child;
2213 * For the direct sp, if the guest pte's dirty bit
2214 * changed form clean to dirty, it will corrupt the
2215 * sp's access: allow writable in the read-only sp,
2216 * so we should update the spte at this point to get
2217 * a new sp with the correct access.
2219 child = to_shadow_page(*sptep & PT64_BASE_ADDR_MASK);
2220 if (child->role.access == direct_access)
2223 drop_parent_pte(child, sptep);
2224 kvm_flush_remote_tlbs_with_address(vcpu->kvm, child->gfn, 1);
2228 /* Returns the number of zapped non-leaf child shadow pages. */
2229 static int mmu_page_zap_pte(struct kvm *kvm, struct kvm_mmu_page *sp,
2230 u64 *spte, struct list_head *invalid_list)
2233 struct kvm_mmu_page *child;
2236 if (is_shadow_present_pte(pte)) {
2237 if (is_last_spte(pte, sp->role.level)) {
2238 drop_spte(kvm, spte);
2240 child = to_shadow_page(pte & PT64_BASE_ADDR_MASK);
2241 drop_parent_pte(child, spte);
2244 * Recursively zap nested TDP SPs, parentless SPs are
2245 * unlikely to be used again in the near future. This
2246 * avoids retaining a large number of stale nested SPs.
2248 if (tdp_enabled && invalid_list &&
2249 child->role.guest_mode && !child->parent_ptes.val)
2250 return kvm_mmu_prepare_zap_page(kvm, child,
2253 } else if (is_mmio_spte(pte)) {
2254 mmu_spte_clear_no_track(spte);
2259 static int kvm_mmu_page_unlink_children(struct kvm *kvm,
2260 struct kvm_mmu_page *sp,
2261 struct list_head *invalid_list)
2266 for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
2267 zapped += mmu_page_zap_pte(kvm, sp, sp->spt + i, invalid_list);
2272 static void kvm_mmu_unlink_parents(struct kvm_mmu_page *sp)
2275 struct rmap_iterator iter;
2277 while ((sptep = rmap_get_first(&sp->parent_ptes, &iter)))
2278 drop_parent_pte(sp, sptep);
2281 static int mmu_zap_unsync_children(struct kvm *kvm,
2282 struct kvm_mmu_page *parent,
2283 struct list_head *invalid_list)
2286 struct mmu_page_path parents;
2287 struct kvm_mmu_pages pages;
2289 if (parent->role.level == PG_LEVEL_4K)
2292 while (mmu_unsync_walk(parent, &pages)) {
2293 struct kvm_mmu_page *sp;
2295 for_each_sp(pages, sp, parents, i) {
2296 kvm_mmu_prepare_zap_page(kvm, sp, invalid_list);
2297 mmu_pages_clear_parents(&parents);
2305 static bool __kvm_mmu_prepare_zap_page(struct kvm *kvm,
2306 struct kvm_mmu_page *sp,
2307 struct list_head *invalid_list,
2310 bool list_unstable, zapped_root = false;
2312 trace_kvm_mmu_prepare_zap_page(sp);
2313 ++kvm->stat.mmu_shadow_zapped;
2314 *nr_zapped = mmu_zap_unsync_children(kvm, sp, invalid_list);
2315 *nr_zapped += kvm_mmu_page_unlink_children(kvm, sp, invalid_list);
2316 kvm_mmu_unlink_parents(sp);
2318 /* Zapping children means active_mmu_pages has become unstable. */
2319 list_unstable = *nr_zapped;
2321 if (!sp->role.invalid && sp_has_gptes(sp))
2322 unaccount_shadowed(kvm, sp);
2325 kvm_unlink_unsync_page(kvm, sp);
2326 if (!sp->root_count) {
2331 * Already invalid pages (previously active roots) are not on
2332 * the active page list. See list_del() in the "else" case of
2335 if (sp->role.invalid)
2336 list_add(&sp->link, invalid_list);
2338 list_move(&sp->link, invalid_list);
2339 kvm_mod_used_mmu_pages(kvm, -1);
2342 * Remove the active root from the active page list, the root
2343 * will be explicitly freed when the root_count hits zero.
2345 list_del(&sp->link);
2348 * Obsolete pages cannot be used on any vCPUs, see the comment
2349 * in kvm_mmu_zap_all_fast(). Note, is_obsolete_sp() also
2350 * treats invalid shadow pages as being obsolete.
2352 zapped_root = !is_obsolete_sp(kvm, sp);
2355 if (sp->lpage_disallowed)
2356 unaccount_huge_nx_page(kvm, sp);
2358 sp->role.invalid = 1;
2361 * Make the request to free obsolete roots after marking the root
2362 * invalid, otherwise other vCPUs may not see it as invalid.
2365 kvm_make_all_cpus_request(kvm, KVM_REQ_MMU_FREE_OBSOLETE_ROOTS);
2366 return list_unstable;
2369 static bool kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
2370 struct list_head *invalid_list)
2374 __kvm_mmu_prepare_zap_page(kvm, sp, invalid_list, &nr_zapped);
2378 static void kvm_mmu_commit_zap_page(struct kvm *kvm,
2379 struct list_head *invalid_list)
2381 struct kvm_mmu_page *sp, *nsp;
2383 if (list_empty(invalid_list))
2387 * We need to make sure everyone sees our modifications to
2388 * the page tables and see changes to vcpu->mode here. The barrier
2389 * in the kvm_flush_remote_tlbs() achieves this. This pairs
2390 * with vcpu_enter_guest and walk_shadow_page_lockless_begin/end.
2392 * In addition, kvm_flush_remote_tlbs waits for all vcpus to exit
2393 * guest mode and/or lockless shadow page table walks.
2395 kvm_flush_remote_tlbs(kvm);
2397 list_for_each_entry_safe(sp, nsp, invalid_list, link) {
2398 WARN_ON(!sp->role.invalid || sp->root_count);
2399 kvm_mmu_free_page(sp);
2403 static unsigned long kvm_mmu_zap_oldest_mmu_pages(struct kvm *kvm,
2404 unsigned long nr_to_zap)
2406 unsigned long total_zapped = 0;
2407 struct kvm_mmu_page *sp, *tmp;
2408 LIST_HEAD(invalid_list);
2412 if (list_empty(&kvm->arch.active_mmu_pages))
2416 list_for_each_entry_safe_reverse(sp, tmp, &kvm->arch.active_mmu_pages, link) {
2418 * Don't zap active root pages, the page itself can't be freed
2419 * and zapping it will just force vCPUs to realloc and reload.
2424 unstable = __kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list,
2426 total_zapped += nr_zapped;
2427 if (total_zapped >= nr_to_zap)
2434 kvm_mmu_commit_zap_page(kvm, &invalid_list);
2436 kvm->stat.mmu_recycled += total_zapped;
2437 return total_zapped;
2440 static inline unsigned long kvm_mmu_available_pages(struct kvm *kvm)
2442 if (kvm->arch.n_max_mmu_pages > kvm->arch.n_used_mmu_pages)
2443 return kvm->arch.n_max_mmu_pages -
2444 kvm->arch.n_used_mmu_pages;
2449 static int make_mmu_pages_available(struct kvm_vcpu *vcpu)
2451 unsigned long avail = kvm_mmu_available_pages(vcpu->kvm);
2453 if (likely(avail >= KVM_MIN_FREE_MMU_PAGES))
2456 kvm_mmu_zap_oldest_mmu_pages(vcpu->kvm, KVM_REFILL_PAGES - avail);
2459 * Note, this check is intentionally soft, it only guarantees that one
2460 * page is available, while the caller may end up allocating as many as
2461 * four pages, e.g. for PAE roots or for 5-level paging. Temporarily
2462 * exceeding the (arbitrary by default) limit will not harm the host,
2463 * being too aggressive may unnecessarily kill the guest, and getting an
2464 * exact count is far more trouble than it's worth, especially in the
2467 if (!kvm_mmu_available_pages(vcpu->kvm))
2473 * Changing the number of mmu pages allocated to the vm
2474 * Note: if goal_nr_mmu_pages is too small, you will get dead lock
2476 void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned long goal_nr_mmu_pages)
2478 write_lock(&kvm->mmu_lock);
2480 if (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages) {
2481 kvm_mmu_zap_oldest_mmu_pages(kvm, kvm->arch.n_used_mmu_pages -
2484 goal_nr_mmu_pages = kvm->arch.n_used_mmu_pages;
2487 kvm->arch.n_max_mmu_pages = goal_nr_mmu_pages;
2489 write_unlock(&kvm->mmu_lock);
2492 int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
2494 struct kvm_mmu_page *sp;
2495 LIST_HEAD(invalid_list);
2498 pgprintk("%s: looking for gfn %llx\n", __func__, gfn);
2500 write_lock(&kvm->mmu_lock);
2501 for_each_gfn_valid_sp_with_gptes(kvm, sp, gfn) {
2502 pgprintk("%s: gfn %llx role %x\n", __func__, gfn,
2505 kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
2507 kvm_mmu_commit_zap_page(kvm, &invalid_list);
2508 write_unlock(&kvm->mmu_lock);
2513 static int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
2518 if (vcpu->arch.mmu->root_role.direct)
2521 gpa = kvm_mmu_gva_to_gpa_read(vcpu, gva, NULL);
2523 r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
2528 static void kvm_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
2530 trace_kvm_mmu_unsync_page(sp);
2531 ++kvm->stat.mmu_unsync;
2534 kvm_mmu_mark_parents_unsync(sp);
2538 * Attempt to unsync any shadow pages that can be reached by the specified gfn,
2539 * KVM is creating a writable mapping for said gfn. Returns 0 if all pages
2540 * were marked unsync (or if there is no shadow page), -EPERM if the SPTE must
2541 * be write-protected.
2543 int mmu_try_to_unsync_pages(struct kvm *kvm, const struct kvm_memory_slot *slot,
2544 gfn_t gfn, bool can_unsync, bool prefetch)
2546 struct kvm_mmu_page *sp;
2547 bool locked = false;
2550 * Force write-protection if the page is being tracked. Note, the page
2551 * track machinery is used to write-protect upper-level shadow pages,
2552 * i.e. this guards the role.level == 4K assertion below!
2554 if (kvm_slot_page_track_is_active(kvm, slot, gfn, KVM_PAGE_TRACK_WRITE))
2558 * The page is not write-tracked, mark existing shadow pages unsync
2559 * unless KVM is synchronizing an unsync SP (can_unsync = false). In
2560 * that case, KVM must complete emulation of the guest TLB flush before
2561 * allowing shadow pages to become unsync (writable by the guest).
2563 for_each_gfn_valid_sp_with_gptes(kvm, sp, gfn) {
2574 * TDP MMU page faults require an additional spinlock as they
2575 * run with mmu_lock held for read, not write, and the unsync
2576 * logic is not thread safe. Take the spinklock regardless of
2577 * the MMU type to avoid extra conditionals/parameters, there's
2578 * no meaningful penalty if mmu_lock is held for write.
2582 spin_lock(&kvm->arch.mmu_unsync_pages_lock);
2585 * Recheck after taking the spinlock, a different vCPU
2586 * may have since marked the page unsync. A false
2587 * positive on the unprotected check above is not
2588 * possible as clearing sp->unsync _must_ hold mmu_lock
2589 * for write, i.e. unsync cannot transition from 0->1
2590 * while this CPU holds mmu_lock for read (or write).
2592 if (READ_ONCE(sp->unsync))
2596 WARN_ON(sp->role.level != PG_LEVEL_4K);
2597 kvm_unsync_page(kvm, sp);
2600 spin_unlock(&kvm->arch.mmu_unsync_pages_lock);
2603 * We need to ensure that the marking of unsync pages is visible
2604 * before the SPTE is updated to allow writes because
2605 * kvm_mmu_sync_roots() checks the unsync flags without holding
2606 * the MMU lock and so can race with this. If the SPTE was updated
2607 * before the page had been marked as unsync-ed, something like the
2608 * following could happen:
2611 * ---------------------------------------------------------------------
2612 * 1.2 Host updates SPTE
2614 * 2.1 Guest writes a GPTE for GVA X.
2615 * (GPTE being in the guest page table shadowed
2616 * by the SP from CPU 1.)
2617 * This reads SPTE during the page table walk.
2618 * Since SPTE.W is read as 1, there is no
2621 * 2.2 Guest issues TLB flush.
2622 * That causes a VM Exit.
2624 * 2.3 Walking of unsync pages sees sp->unsync is
2625 * false and skips the page.
2627 * 2.4 Guest accesses GVA X.
2628 * Since the mapping in the SP was not updated,
2629 * so the old mapping for GVA X incorrectly
2633 * (sp->unsync = true)
2635 * The write barrier below ensures that 1.1 happens before 1.2 and thus
2636 * the situation in 2.4 does not arise. It pairs with the read barrier
2637 * in is_unsync_root(), placed between 2.1's load of SPTE.W and 2.3.
2644 static int mmu_set_spte(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot,
2645 u64 *sptep, unsigned int pte_access, gfn_t gfn,
2646 kvm_pfn_t pfn, struct kvm_page_fault *fault)
2648 struct kvm_mmu_page *sp = sptep_to_sp(sptep);
2649 int level = sp->role.level;
2650 int was_rmapped = 0;
2651 int ret = RET_PF_FIXED;
2656 /* Prefetching always gets a writable pfn. */
2657 bool host_writable = !fault || fault->map_writable;
2658 bool prefetch = !fault || fault->prefetch;
2659 bool write_fault = fault && fault->write;
2661 pgprintk("%s: spte %llx write_fault %d gfn %llx\n", __func__,
2662 *sptep, write_fault, gfn);
2664 if (unlikely(is_noslot_pfn(pfn))) {
2665 vcpu->stat.pf_mmio_spte_created++;
2666 mark_mmio_spte(vcpu, sptep, gfn, pte_access);
2667 return RET_PF_EMULATE;
2670 if (is_shadow_present_pte(*sptep)) {
2672 * If we overwrite a PTE page pointer with a 2MB PMD, unlink
2673 * the parent of the now unreachable PTE.
2675 if (level > PG_LEVEL_4K && !is_large_pte(*sptep)) {
2676 struct kvm_mmu_page *child;
2679 child = to_shadow_page(pte & PT64_BASE_ADDR_MASK);
2680 drop_parent_pte(child, sptep);
2682 } else if (pfn != spte_to_pfn(*sptep)) {
2683 pgprintk("hfn old %llx new %llx\n",
2684 spte_to_pfn(*sptep), pfn);
2685 drop_spte(vcpu->kvm, sptep);
2691 wrprot = make_spte(vcpu, sp, slot, pte_access, gfn, pfn, *sptep, prefetch,
2692 true, host_writable, &spte);
2694 if (*sptep == spte) {
2695 ret = RET_PF_SPURIOUS;
2697 flush |= mmu_spte_update(sptep, spte);
2698 trace_kvm_mmu_set_spte(level, gfn, sptep);
2703 ret = RET_PF_EMULATE;
2707 kvm_flush_remote_tlbs_with_address(vcpu->kvm, gfn,
2708 KVM_PAGES_PER_HPAGE(level));
2710 pgprintk("%s: setting spte %llx\n", __func__, *sptep);
2713 WARN_ON_ONCE(ret == RET_PF_SPURIOUS);
2714 kvm_update_page_stats(vcpu->kvm, level, 1);
2715 rmap_add(vcpu, slot, sptep, gfn);
2721 static int direct_pte_prefetch_many(struct kvm_vcpu *vcpu,
2722 struct kvm_mmu_page *sp,
2723 u64 *start, u64 *end)
2725 struct page *pages[PTE_PREFETCH_NUM];
2726 struct kvm_memory_slot *slot;
2727 unsigned int access = sp->role.access;
2731 gfn = kvm_mmu_page_get_gfn(sp, start - sp->spt);
2732 slot = gfn_to_memslot_dirty_bitmap(vcpu, gfn, access & ACC_WRITE_MASK);
2736 ret = gfn_to_page_many_atomic(slot, gfn, pages, end - start);
2740 for (i = 0; i < ret; i++, gfn++, start++) {
2741 mmu_set_spte(vcpu, slot, start, access, gfn,
2742 page_to_pfn(pages[i]), NULL);
2749 static void __direct_pte_prefetch(struct kvm_vcpu *vcpu,
2750 struct kvm_mmu_page *sp, u64 *sptep)
2752 u64 *spte, *start = NULL;
2755 WARN_ON(!sp->role.direct);
2757 i = (sptep - sp->spt) & ~(PTE_PREFETCH_NUM - 1);
2760 for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) {
2761 if (is_shadow_present_pte(*spte) || spte == sptep) {
2764 if (direct_pte_prefetch_many(vcpu, sp, start, spte) < 0)
2771 direct_pte_prefetch_many(vcpu, sp, start, spte);
2774 static void direct_pte_prefetch(struct kvm_vcpu *vcpu, u64 *sptep)
2776 struct kvm_mmu_page *sp;
2778 sp = sptep_to_sp(sptep);
2781 * Without accessed bits, there's no way to distinguish between
2782 * actually accessed translations and prefetched, so disable pte
2783 * prefetch if accessed bits aren't available.
2785 if (sp_ad_disabled(sp))
2788 if (sp->role.level > PG_LEVEL_4K)
2792 * If addresses are being invalidated, skip prefetching to avoid
2793 * accidentally prefetching those addresses.
2795 if (unlikely(vcpu->kvm->mmu_notifier_count))
2798 __direct_pte_prefetch(vcpu, sp, sptep);
2801 static int host_pfn_mapping_level(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
2802 const struct kvm_memory_slot *slot)
2805 unsigned long flags;
2806 int level = PG_LEVEL_4K;
2812 if (!PageCompound(pfn_to_page(pfn)) && !kvm_is_zone_device_pfn(pfn))
2816 * Note, using the already-retrieved memslot and __gfn_to_hva_memslot()
2817 * is not solely for performance, it's also necessary to avoid the
2818 * "writable" check in __gfn_to_hva_many(), which will always fail on
2819 * read-only memslots due to gfn_to_hva() assuming writes. Earlier
2820 * page fault steps have already verified the guest isn't writing a
2821 * read-only memslot.
2823 hva = __gfn_to_hva_memslot(slot, gfn);
2826 * Lookup the mapping level in the current mm. The information
2827 * may become stale soon, but it is safe to use as long as
2828 * 1) mmu_notifier_retry was checked after taking mmu_lock, and
2829 * 2) mmu_lock is taken now.
2831 * We still need to disable IRQs to prevent concurrent tear down
2834 local_irq_save(flags);
2836 pgd = READ_ONCE(*pgd_offset(kvm->mm, hva));
2840 p4d = READ_ONCE(*p4d_offset(&pgd, hva));
2841 if (p4d_none(p4d) || !p4d_present(p4d))
2844 pud = READ_ONCE(*pud_offset(&p4d, hva));
2845 if (pud_none(pud) || !pud_present(pud))
2848 if (pud_large(pud)) {
2849 level = PG_LEVEL_1G;
2853 pmd = READ_ONCE(*pmd_offset(&pud, hva));
2854 if (pmd_none(pmd) || !pmd_present(pmd))
2858 level = PG_LEVEL_2M;
2861 local_irq_restore(flags);
2865 int kvm_mmu_max_mapping_level(struct kvm *kvm,
2866 const struct kvm_memory_slot *slot, gfn_t gfn,
2867 kvm_pfn_t pfn, int max_level)
2869 struct kvm_lpage_info *linfo;
2872 max_level = min(max_level, max_huge_page_level);
2873 for ( ; max_level > PG_LEVEL_4K; max_level--) {
2874 linfo = lpage_info_slot(gfn, slot, max_level);
2875 if (!linfo->disallow_lpage)
2879 if (max_level == PG_LEVEL_4K)
2882 host_level = host_pfn_mapping_level(kvm, gfn, pfn, slot);
2883 return min(host_level, max_level);
2886 void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
2888 struct kvm_memory_slot *slot = fault->slot;
2891 fault->huge_page_disallowed = fault->exec && fault->nx_huge_page_workaround_enabled;
2893 if (unlikely(fault->max_level == PG_LEVEL_4K))
2896 if (is_error_noslot_pfn(fault->pfn) || kvm_is_reserved_pfn(fault->pfn))
2899 if (kvm_slot_dirty_track_enabled(slot))
2903 * Enforce the iTLB multihit workaround after capturing the requested
2904 * level, which will be used to do precise, accurate accounting.
2906 fault->req_level = kvm_mmu_max_mapping_level(vcpu->kvm, slot,
2907 fault->gfn, fault->pfn,
2909 if (fault->req_level == PG_LEVEL_4K || fault->huge_page_disallowed)
2913 * mmu_notifier_retry() was successful and mmu_lock is held, so
2914 * the pmd can't be split from under us.
2916 fault->goal_level = fault->req_level;
2917 mask = KVM_PAGES_PER_HPAGE(fault->goal_level) - 1;
2918 VM_BUG_ON((fault->gfn & mask) != (fault->pfn & mask));
2919 fault->pfn &= ~mask;
2922 void disallowed_hugepage_adjust(struct kvm_page_fault *fault, u64 spte, int cur_level)
2924 if (cur_level > PG_LEVEL_4K &&
2925 cur_level == fault->goal_level &&
2926 is_shadow_present_pte(spte) &&
2927 !is_large_pte(spte)) {
2929 * A small SPTE exists for this pfn, but FNAME(fetch)
2930 * and __direct_map would like to create a large PTE
2931 * instead: just force them to go down another level,
2932 * patching back for them into pfn the next 9 bits of
2935 u64 page_mask = KVM_PAGES_PER_HPAGE(cur_level) -
2936 KVM_PAGES_PER_HPAGE(cur_level - 1);
2937 fault->pfn |= fault->gfn & page_mask;
2938 fault->goal_level--;
2942 static int __direct_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
2944 struct kvm_shadow_walk_iterator it;
2945 struct kvm_mmu_page *sp;
2947 gfn_t base_gfn = fault->gfn;
2949 kvm_mmu_hugepage_adjust(vcpu, fault);
2951 trace_kvm_mmu_spte_requested(fault);
2952 for_each_shadow_entry(vcpu, fault->addr, it) {
2954 * We cannot overwrite existing page tables with an NX
2955 * large page, as the leaf could be executable.
2957 if (fault->nx_huge_page_workaround_enabled)
2958 disallowed_hugepage_adjust(fault, *it.sptep, it.level);
2960 base_gfn = fault->gfn & ~(KVM_PAGES_PER_HPAGE(it.level) - 1);
2961 if (it.level == fault->goal_level)
2964 drop_large_spte(vcpu, it.sptep);
2965 if (is_shadow_present_pte(*it.sptep))
2968 sp = kvm_mmu_get_page(vcpu, base_gfn, it.addr,
2969 it.level - 1, true, ACC_ALL);
2971 link_shadow_page(vcpu, it.sptep, sp);
2972 if (fault->is_tdp && fault->huge_page_disallowed &&
2973 fault->req_level >= it.level)
2974 account_huge_nx_page(vcpu->kvm, sp);
2977 if (WARN_ON_ONCE(it.level != fault->goal_level))
2980 ret = mmu_set_spte(vcpu, fault->slot, it.sptep, ACC_ALL,
2981 base_gfn, fault->pfn, fault);
2982 if (ret == RET_PF_SPURIOUS)
2985 direct_pte_prefetch(vcpu, it.sptep);
2989 static void kvm_send_hwpoison_signal(unsigned long address, struct task_struct *tsk)
2991 send_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, PAGE_SHIFT, tsk);
2994 static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_t pfn)
2997 * Do not cache the mmio info caused by writing the readonly gfn
2998 * into the spte otherwise read access on readonly gfn also can
2999 * caused mmio page fault and treat it as mmio access.
3001 if (pfn == KVM_PFN_ERR_RO_FAULT)
3002 return RET_PF_EMULATE;
3004 if (pfn == KVM_PFN_ERR_HWPOISON) {
3005 kvm_send_hwpoison_signal(kvm_vcpu_gfn_to_hva(vcpu, gfn), current);
3006 return RET_PF_RETRY;
3012 static int handle_abnormal_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
3013 unsigned int access)
3015 /* The pfn is invalid, report the error! */
3016 if (unlikely(is_error_pfn(fault->pfn)))
3017 return kvm_handle_bad_page(vcpu, fault->gfn, fault->pfn);
3019 if (unlikely(!fault->slot)) {
3020 gva_t gva = fault->is_tdp ? 0 : fault->addr;
3022 vcpu_cache_mmio_info(vcpu, gva, fault->gfn,
3023 access & shadow_mmio_access_mask);
3025 * If MMIO caching is disabled, emulate immediately without
3026 * touching the shadow page tables as attempting to install an
3027 * MMIO SPTE will just be an expensive nop. Do not cache MMIO
3028 * whose gfn is greater than host.MAXPHYADDR, any guest that
3029 * generates such gfns is running nested and is being tricked
3030 * by L0 userspace (you can observe gfn > L1.MAXPHYADDR if
3031 * and only if L1's MAXPHYADDR is inaccurate with respect to
3034 if (unlikely(!enable_mmio_caching) ||
3035 unlikely(fault->gfn > kvm_mmu_max_gfn()))
3036 return RET_PF_EMULATE;
3039 return RET_PF_CONTINUE;
3042 static bool page_fault_can_be_fast(struct kvm_page_fault *fault)
3045 * Page faults with reserved bits set, i.e. faults on MMIO SPTEs, only
3046 * reach the common page fault handler if the SPTE has an invalid MMIO
3047 * generation number. Refreshing the MMIO generation needs to go down
3048 * the slow path. Note, EPT Misconfigs do NOT set the PRESENT flag!
3054 * #PF can be fast if:
3056 * 1. The shadow page table entry is not present and A/D bits are
3057 * disabled _by KVM_, which could mean that the fault is potentially
3058 * caused by access tracking (if enabled). If A/D bits are enabled
3059 * by KVM, but disabled by L1 for L2, KVM is forced to disable A/D
3060 * bits for L2 and employ access tracking, but the fast page fault
3061 * mechanism only supports direct MMUs.
3062 * 2. The shadow page table entry is present, the access is a write,
3063 * and no reserved bits are set (MMIO SPTEs cannot be "fixed"), i.e.
3064 * the fault was caused by a write-protection violation. If the
3065 * SPTE is MMU-writable (determined later), the fault can be fixed
3066 * by setting the Writable bit, which can be done out of mmu_lock.
3068 if (!fault->present)
3069 return !kvm_ad_enabled();
3072 * Note, instruction fetches and writes are mutually exclusive, ignore
3075 return fault->write;
3079 * Returns true if the SPTE was fixed successfully. Otherwise,
3080 * someone else modified the SPTE from its original value.
3083 fast_pf_fix_direct_spte(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
3084 u64 *sptep, u64 old_spte, u64 new_spte)
3087 * Theoretically we could also set dirty bit (and flush TLB) here in
3088 * order to eliminate unnecessary PML logging. See comments in
3089 * set_spte. But fast_page_fault is very unlikely to happen with PML
3090 * enabled, so we do not do this. This might result in the same GPA
3091 * to be logged in PML buffer again when the write really happens, and
3092 * eventually to be called by mark_page_dirty twice. But it's also no
3093 * harm. This also avoids the TLB flush needed after setting dirty bit
3094 * so non-PML cases won't be impacted.
3096 * Compare with set_spte where instead shadow_dirty_mask is set.
3098 if (cmpxchg64(sptep, old_spte, new_spte) != old_spte)
3101 if (is_writable_pte(new_spte) && !is_writable_pte(old_spte))
3102 mark_page_dirty_in_slot(vcpu->kvm, fault->slot, fault->gfn);
3107 static bool is_access_allowed(struct kvm_page_fault *fault, u64 spte)
3110 return is_executable_pte(spte);
3113 return is_writable_pte(spte);
3115 /* Fault was on Read access */
3116 return spte & PT_PRESENT_MASK;
3120 * Returns the last level spte pointer of the shadow page walk for the given
3121 * gpa, and sets *spte to the spte value. This spte may be non-preset. If no
3122 * walk could be performed, returns NULL and *spte does not contain valid data.
3125 * - Must be called between walk_shadow_page_lockless_{begin,end}.
3126 * - The returned sptep must not be used after walk_shadow_page_lockless_end.
3128 static u64 *fast_pf_get_last_sptep(struct kvm_vcpu *vcpu, gpa_t gpa, u64 *spte)
3130 struct kvm_shadow_walk_iterator iterator;
3134 for_each_shadow_entry_lockless(vcpu, gpa, iterator, old_spte) {
3135 sptep = iterator.sptep;
3143 * Returns one of RET_PF_INVALID, RET_PF_FIXED or RET_PF_SPURIOUS.
3145 static int fast_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
3147 struct kvm_mmu_page *sp;
3148 int ret = RET_PF_INVALID;
3151 uint retry_count = 0;
3153 if (!page_fault_can_be_fast(fault))
3156 walk_shadow_page_lockless_begin(vcpu);
3161 if (is_tdp_mmu(vcpu->arch.mmu))
3162 sptep = kvm_tdp_mmu_fast_pf_get_last_sptep(vcpu, fault->addr, &spte);
3164 sptep = fast_pf_get_last_sptep(vcpu, fault->addr, &spte);
3166 if (!is_shadow_present_pte(spte))
3169 sp = sptep_to_sp(sptep);
3170 if (!is_last_spte(spte, sp->role.level))
3174 * Check whether the memory access that caused the fault would
3175 * still cause it if it were to be performed right now. If not,
3176 * then this is a spurious fault caused by TLB lazily flushed,
3177 * or some other CPU has already fixed the PTE after the
3178 * current CPU took the fault.
3180 * Need not check the access of upper level table entries since
3181 * they are always ACC_ALL.
3183 if (is_access_allowed(fault, spte)) {
3184 ret = RET_PF_SPURIOUS;
3191 * KVM only supports fixing page faults outside of MMU lock for
3192 * direct MMUs, nested MMUs are always indirect, and KVM always
3193 * uses A/D bits for non-nested MMUs. Thus, if A/D bits are
3194 * enabled, the SPTE can't be an access-tracked SPTE.
3196 if (unlikely(!kvm_ad_enabled()) && is_access_track_spte(spte))
3197 new_spte = restore_acc_track_spte(new_spte);
3200 * To keep things simple, only SPTEs that are MMU-writable can
3201 * be made fully writable outside of mmu_lock, e.g. only SPTEs
3202 * that were write-protected for dirty-logging or access
3203 * tracking are handled here. Don't bother checking if the
3204 * SPTE is writable to prioritize running with A/D bits enabled.
3205 * The is_access_allowed() check above handles the common case
3206 * of the fault being spurious, and the SPTE is known to be
3207 * shadow-present, i.e. except for access tracking restoration
3208 * making the new SPTE writable, the check is wasteful.
3210 if (fault->write && is_mmu_writable_spte(spte)) {
3211 new_spte |= PT_WRITABLE_MASK;
3214 * Do not fix write-permission on the large spte when
3215 * dirty logging is enabled. Since we only dirty the
3216 * first page into the dirty-bitmap in
3217 * fast_pf_fix_direct_spte(), other pages are missed
3218 * if its slot has dirty logging enabled.
3220 * Instead, we let the slow page fault path create a
3221 * normal spte to fix the access.
3223 if (sp->role.level > PG_LEVEL_4K &&
3224 kvm_slot_dirty_track_enabled(fault->slot))
3228 /* Verify that the fault can be handled in the fast path */
3229 if (new_spte == spte ||
3230 !is_access_allowed(fault, new_spte))
3234 * Currently, fast page fault only works for direct mapping
3235 * since the gfn is not stable for indirect shadow page. See
3236 * Documentation/virt/kvm/locking.rst to get more detail.
3238 if (fast_pf_fix_direct_spte(vcpu, fault, sptep, spte, new_spte)) {
3243 if (++retry_count > 4) {
3244 printk_once(KERN_WARNING
3245 "kvm: Fast #PF retrying more than 4 times.\n");
3251 trace_fast_page_fault(vcpu, fault, sptep, spte, ret);
3252 walk_shadow_page_lockless_end(vcpu);
3254 if (ret != RET_PF_INVALID)
3255 vcpu->stat.pf_fast++;
3260 static void mmu_free_root_page(struct kvm *kvm, hpa_t *root_hpa,
3261 struct list_head *invalid_list)
3263 struct kvm_mmu_page *sp;
3265 if (!VALID_PAGE(*root_hpa))
3268 sp = to_shadow_page(*root_hpa & PT64_BASE_ADDR_MASK);
3272 if (is_tdp_mmu_page(sp))
3273 kvm_tdp_mmu_put_root(kvm, sp, false);
3274 else if (!--sp->root_count && sp->role.invalid)
3275 kvm_mmu_prepare_zap_page(kvm, sp, invalid_list);
3277 *root_hpa = INVALID_PAGE;
3280 /* roots_to_free must be some combination of the KVM_MMU_ROOT_* flags */
3281 void kvm_mmu_free_roots(struct kvm *kvm, struct kvm_mmu *mmu,
3282 ulong roots_to_free)
3285 LIST_HEAD(invalid_list);
3286 bool free_active_root;
3288 BUILD_BUG_ON(KVM_MMU_NUM_PREV_ROOTS >= BITS_PER_LONG);
3290 /* Before acquiring the MMU lock, see if we need to do any real work. */
3291 free_active_root = (roots_to_free & KVM_MMU_ROOT_CURRENT)
3292 && VALID_PAGE(mmu->root.hpa);
3294 if (!free_active_root) {
3295 for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++)
3296 if ((roots_to_free & KVM_MMU_ROOT_PREVIOUS(i)) &&
3297 VALID_PAGE(mmu->prev_roots[i].hpa))
3300 if (i == KVM_MMU_NUM_PREV_ROOTS)
3304 write_lock(&kvm->mmu_lock);
3306 for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++)
3307 if (roots_to_free & KVM_MMU_ROOT_PREVIOUS(i))
3308 mmu_free_root_page(kvm, &mmu->prev_roots[i].hpa,
3311 if (free_active_root) {
3312 if (to_shadow_page(mmu->root.hpa)) {
3313 mmu_free_root_page(kvm, &mmu->root.hpa, &invalid_list);
3314 } else if (mmu->pae_root) {
3315 for (i = 0; i < 4; ++i) {
3316 if (!IS_VALID_PAE_ROOT(mmu->pae_root[i]))
3319 mmu_free_root_page(kvm, &mmu->pae_root[i],
3321 mmu->pae_root[i] = INVALID_PAE_ROOT;
3324 mmu->root.hpa = INVALID_PAGE;
3328 kvm_mmu_commit_zap_page(kvm, &invalid_list);
3329 write_unlock(&kvm->mmu_lock);
3331 EXPORT_SYMBOL_GPL(kvm_mmu_free_roots);
3333 void kvm_mmu_free_guest_mode_roots(struct kvm *kvm, struct kvm_mmu *mmu)
3335 unsigned long roots_to_free = 0;
3340 * This should not be called while L2 is active, L2 can't invalidate
3341 * _only_ its own roots, e.g. INVVPID unconditionally exits.
3343 WARN_ON_ONCE(mmu->root_role.guest_mode);
3345 for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) {
3346 root_hpa = mmu->prev_roots[i].hpa;
3347 if (!VALID_PAGE(root_hpa))
3350 if (!to_shadow_page(root_hpa) ||
3351 to_shadow_page(root_hpa)->role.guest_mode)
3352 roots_to_free |= KVM_MMU_ROOT_PREVIOUS(i);
3355 kvm_mmu_free_roots(kvm, mmu, roots_to_free);
3357 EXPORT_SYMBOL_GPL(kvm_mmu_free_guest_mode_roots);
3360 static int mmu_check_root(struct kvm_vcpu *vcpu, gfn_t root_gfn)
3364 if (!kvm_vcpu_is_visible_gfn(vcpu, root_gfn)) {
3365 kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
3372 static hpa_t mmu_alloc_root(struct kvm_vcpu *vcpu, gfn_t gfn, gva_t gva,
3373 u8 level, bool direct)
3375 struct kvm_mmu_page *sp;
3377 sp = kvm_mmu_get_page(vcpu, gfn, gva, level, direct, ACC_ALL);
3380 return __pa(sp->spt);
3383 static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
3385 struct kvm_mmu *mmu = vcpu->arch.mmu;
3386 u8 shadow_root_level = mmu->root_role.level;
3391 write_lock(&vcpu->kvm->mmu_lock);
3392 r = make_mmu_pages_available(vcpu);
3396 if (is_tdp_mmu_enabled(vcpu->kvm)) {
3397 root = kvm_tdp_mmu_get_vcpu_root_hpa(vcpu);
3398 mmu->root.hpa = root;
3399 } else if (shadow_root_level >= PT64_ROOT_4LEVEL) {
3400 root = mmu_alloc_root(vcpu, 0, 0, shadow_root_level, true);
3401 mmu->root.hpa = root;
3402 } else if (shadow_root_level == PT32E_ROOT_LEVEL) {
3403 if (WARN_ON_ONCE(!mmu->pae_root)) {
3408 for (i = 0; i < 4; ++i) {
3409 WARN_ON_ONCE(IS_VALID_PAE_ROOT(mmu->pae_root[i]));
3411 root = mmu_alloc_root(vcpu, i << (30 - PAGE_SHIFT),
3412 i << 30, PT32_ROOT_LEVEL, true);
3413 mmu->pae_root[i] = root | PT_PRESENT_MASK |
3416 mmu->root.hpa = __pa(mmu->pae_root);
3418 WARN_ONCE(1, "Bad TDP root level = %d\n", shadow_root_level);
3423 /* root.pgd is ignored for direct MMUs. */
3426 write_unlock(&vcpu->kvm->mmu_lock);
3430 static int mmu_first_shadow_root_alloc(struct kvm *kvm)
3432 struct kvm_memslots *slots;
3433 struct kvm_memory_slot *slot;
3437 * Check if this is the first shadow root being allocated before
3440 if (kvm_shadow_root_allocated(kvm))
3443 mutex_lock(&kvm->slots_arch_lock);
3445 /* Recheck, under the lock, whether this is the first shadow root. */
3446 if (kvm_shadow_root_allocated(kvm))
3450 * Check if anything actually needs to be allocated, e.g. all metadata
3451 * will be allocated upfront if TDP is disabled.
3453 if (kvm_memslots_have_rmaps(kvm) &&
3454 kvm_page_track_write_tracking_enabled(kvm))
3457 for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
3458 slots = __kvm_memslots(kvm, i);
3459 kvm_for_each_memslot(slot, bkt, slots) {
3461 * Both of these functions are no-ops if the target is
3462 * already allocated, so unconditionally calling both
3463 * is safe. Intentionally do NOT free allocations on
3464 * failure to avoid having to track which allocations
3465 * were made now versus when the memslot was created.
3466 * The metadata is guaranteed to be freed when the slot
3467 * is freed, and will be kept/used if userspace retries
3468 * KVM_RUN instead of killing the VM.
3470 r = memslot_rmap_alloc(slot, slot->npages);
3473 r = kvm_page_track_write_tracking_alloc(slot);
3480 * Ensure that shadow_root_allocated becomes true strictly after
3481 * all the related pointers are set.
3484 smp_store_release(&kvm->arch.shadow_root_allocated, true);
3487 mutex_unlock(&kvm->slots_arch_lock);
3491 static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
3493 struct kvm_mmu *mmu = vcpu->arch.mmu;
3494 u64 pdptrs[4], pm_mask;
3495 gfn_t root_gfn, root_pgd;
3500 root_pgd = mmu->get_guest_pgd(vcpu);
3501 root_gfn = root_pgd >> PAGE_SHIFT;
3503 if (mmu_check_root(vcpu, root_gfn))
3507 * On SVM, reading PDPTRs might access guest memory, which might fault
3508 * and thus might sleep. Grab the PDPTRs before acquiring mmu_lock.
3510 if (mmu->cpu_role.base.level == PT32E_ROOT_LEVEL) {
3511 for (i = 0; i < 4; ++i) {
3512 pdptrs[i] = mmu->get_pdptr(vcpu, i);
3513 if (!(pdptrs[i] & PT_PRESENT_MASK))
3516 if (mmu_check_root(vcpu, pdptrs[i] >> PAGE_SHIFT))
3521 r = mmu_first_shadow_root_alloc(vcpu->kvm);
3525 write_lock(&vcpu->kvm->mmu_lock);
3526 r = make_mmu_pages_available(vcpu);
3531 * Do we shadow a long mode page table? If so we need to
3532 * write-protect the guests page table root.
3534 if (mmu->cpu_role.base.level >= PT64_ROOT_4LEVEL) {
3535 root = mmu_alloc_root(vcpu, root_gfn, 0,
3536 mmu->root_role.level, false);
3537 mmu->root.hpa = root;
3541 if (WARN_ON_ONCE(!mmu->pae_root)) {
3547 * We shadow a 32 bit page table. This may be a legacy 2-level
3548 * or a PAE 3-level page table. In either case we need to be aware that
3549 * the shadow page table may be a PAE or a long mode page table.
3551 pm_mask = PT_PRESENT_MASK | shadow_me_value;
3552 if (mmu->root_role.level >= PT64_ROOT_4LEVEL) {
3553 pm_mask |= PT_ACCESSED_MASK | PT_WRITABLE_MASK | PT_USER_MASK;
3555 if (WARN_ON_ONCE(!mmu->pml4_root)) {
3559 mmu->pml4_root[0] = __pa(mmu->pae_root) | pm_mask;
3561 if (mmu->root_role.level == PT64_ROOT_5LEVEL) {
3562 if (WARN_ON_ONCE(!mmu->pml5_root)) {
3566 mmu->pml5_root[0] = __pa(mmu->pml4_root) | pm_mask;
3570 for (i = 0; i < 4; ++i) {
3571 WARN_ON_ONCE(IS_VALID_PAE_ROOT(mmu->pae_root[i]));
3573 if (mmu->cpu_role.base.level == PT32E_ROOT_LEVEL) {
3574 if (!(pdptrs[i] & PT_PRESENT_MASK)) {
3575 mmu->pae_root[i] = INVALID_PAE_ROOT;
3578 root_gfn = pdptrs[i] >> PAGE_SHIFT;
3581 root = mmu_alloc_root(vcpu, root_gfn, i << 30,
3582 PT32_ROOT_LEVEL, false);
3583 mmu->pae_root[i] = root | pm_mask;
3586 if (mmu->root_role.level == PT64_ROOT_5LEVEL)
3587 mmu->root.hpa = __pa(mmu->pml5_root);
3588 else if (mmu->root_role.level == PT64_ROOT_4LEVEL)
3589 mmu->root.hpa = __pa(mmu->pml4_root);
3591 mmu->root.hpa = __pa(mmu->pae_root);
3594 mmu->root.pgd = root_pgd;
3596 write_unlock(&vcpu->kvm->mmu_lock);
3601 static int mmu_alloc_special_roots(struct kvm_vcpu *vcpu)
3603 struct kvm_mmu *mmu = vcpu->arch.mmu;
3604 bool need_pml5 = mmu->root_role.level > PT64_ROOT_4LEVEL;
3605 u64 *pml5_root = NULL;
3606 u64 *pml4_root = NULL;
3610 * When shadowing 32-bit or PAE NPT with 64-bit NPT, the PML4 and PDP
3611 * tables are allocated and initialized at root creation as there is no
3612 * equivalent level in the guest's NPT to shadow. Allocate the tables
3613 * on demand, as running a 32-bit L1 VMM on 64-bit KVM is very rare.
3615 if (mmu->root_role.direct ||
3616 mmu->cpu_role.base.level >= PT64_ROOT_4LEVEL ||
3617 mmu->root_role.level < PT64_ROOT_4LEVEL)
3621 * NPT, the only paging mode that uses this horror, uses a fixed number
3622 * of levels for the shadow page tables, e.g. all MMUs are 4-level or
3623 * all MMus are 5-level. Thus, this can safely require that pml5_root
3624 * is allocated if the other roots are valid and pml5 is needed, as any
3625 * prior MMU would also have required pml5.
3627 if (mmu->pae_root && mmu->pml4_root && (!need_pml5 || mmu->pml5_root))
3631 * The special roots should always be allocated in concert. Yell and
3632 * bail if KVM ends up in a state where only one of the roots is valid.
3634 if (WARN_ON_ONCE(!tdp_enabled || mmu->pae_root || mmu->pml4_root ||
3635 (need_pml5 && mmu->pml5_root)))
3639 * Unlike 32-bit NPT, the PDP table doesn't need to be in low mem, and
3640 * doesn't need to be decrypted.
3642 pae_root = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT);
3646 #ifdef CONFIG_X86_64
3647 pml4_root = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT);
3652 pml5_root = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT);
3658 mmu->pae_root = pae_root;
3659 mmu->pml4_root = pml4_root;
3660 mmu->pml5_root = pml5_root;
3664 #ifdef CONFIG_X86_64
3666 free_page((unsigned long)pml4_root);
3668 free_page((unsigned long)pae_root);
3673 static bool is_unsync_root(hpa_t root)
3675 struct kvm_mmu_page *sp;
3677 if (!VALID_PAGE(root))
3681 * The read barrier orders the CPU's read of SPTE.W during the page table
3682 * walk before the reads of sp->unsync/sp->unsync_children here.
3684 * Even if another CPU was marking the SP as unsync-ed simultaneously,
3685 * any guest page table changes are not guaranteed to be visible anyway
3686 * until this VCPU issues a TLB flush strictly after those changes are
3687 * made. We only need to ensure that the other CPU sets these flags
3688 * before any actual changes to the page tables are made. The comments
3689 * in mmu_try_to_unsync_pages() describe what could go wrong if this
3690 * requirement isn't satisfied.
3693 sp = to_shadow_page(root);
3696 * PAE roots (somewhat arbitrarily) aren't backed by shadow pages, the
3697 * PDPTEs for a given PAE root need to be synchronized individually.
3699 if (WARN_ON_ONCE(!sp))
3702 if (sp->unsync || sp->unsync_children)
3708 void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
3711 struct kvm_mmu_page *sp;
3713 if (vcpu->arch.mmu->root_role.direct)
3716 if (!VALID_PAGE(vcpu->arch.mmu->root.hpa))
3719 vcpu_clear_mmio_info(vcpu, MMIO_GVA_ANY);
3721 if (vcpu->arch.mmu->cpu_role.base.level >= PT64_ROOT_4LEVEL) {
3722 hpa_t root = vcpu->arch.mmu->root.hpa;
3723 sp = to_shadow_page(root);
3725 if (!is_unsync_root(root))
3728 write_lock(&vcpu->kvm->mmu_lock);
3729 mmu_sync_children(vcpu, sp, true);
3730 write_unlock(&vcpu->kvm->mmu_lock);
3734 write_lock(&vcpu->kvm->mmu_lock);
3736 for (i = 0; i < 4; ++i) {
3737 hpa_t root = vcpu->arch.mmu->pae_root[i];
3739 if (IS_VALID_PAE_ROOT(root)) {
3740 root &= PT64_BASE_ADDR_MASK;
3741 sp = to_shadow_page(root);
3742 mmu_sync_children(vcpu, sp, true);
3746 write_unlock(&vcpu->kvm->mmu_lock);
3749 void kvm_mmu_sync_prev_roots(struct kvm_vcpu *vcpu)
3751 unsigned long roots_to_free = 0;
3754 for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++)
3755 if (is_unsync_root(vcpu->arch.mmu->prev_roots[i].hpa))
3756 roots_to_free |= KVM_MMU_ROOT_PREVIOUS(i);
3758 /* sync prev_roots by simply freeing them */
3759 kvm_mmu_free_roots(vcpu->kvm, vcpu->arch.mmu, roots_to_free);
3762 static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
3763 gpa_t vaddr, u64 access,
3764 struct x86_exception *exception)
3767 exception->error_code = 0;
3768 return kvm_translate_gpa(vcpu, mmu, vaddr, access, exception);
3771 static bool mmio_info_in_cache(struct kvm_vcpu *vcpu, u64 addr, bool direct)
3774 * A nested guest cannot use the MMIO cache if it is using nested
3775 * page tables, because cr2 is a nGPA while the cache stores GPAs.
3777 if (mmu_is_nested(vcpu))
3781 return vcpu_match_mmio_gpa(vcpu, addr);
3783 return vcpu_match_mmio_gva(vcpu, addr);
3787 * Return the level of the lowest level SPTE added to sptes.
3788 * That SPTE may be non-present.
3790 * Must be called between walk_shadow_page_lockless_{begin,end}.
3792 static int get_walk(struct kvm_vcpu *vcpu, u64 addr, u64 *sptes, int *root_level)
3794 struct kvm_shadow_walk_iterator iterator;
3798 for (shadow_walk_init(&iterator, vcpu, addr),
3799 *root_level = iterator.level;
3800 shadow_walk_okay(&iterator);
3801 __shadow_walk_next(&iterator, spte)) {
3802 leaf = iterator.level;
3803 spte = mmu_spte_get_lockless(iterator.sptep);
3811 /* return true if reserved bit(s) are detected on a valid, non-MMIO SPTE. */
3812 static bool get_mmio_spte(struct kvm_vcpu *vcpu, u64 addr, u64 *sptep)
3814 u64 sptes[PT64_ROOT_MAX_LEVEL + 1];
3815 struct rsvd_bits_validate *rsvd_check;
3816 int root, leaf, level;
3817 bool reserved = false;
3819 walk_shadow_page_lockless_begin(vcpu);
3821 if (is_tdp_mmu(vcpu->arch.mmu))
3822 leaf = kvm_tdp_mmu_get_walk(vcpu, addr, sptes, &root);
3824 leaf = get_walk(vcpu, addr, sptes, &root);
3826 walk_shadow_page_lockless_end(vcpu);
3828 if (unlikely(leaf < 0)) {
3833 *sptep = sptes[leaf];
3836 * Skip reserved bits checks on the terminal leaf if it's not a valid
3837 * SPTE. Note, this also (intentionally) skips MMIO SPTEs, which, by
3838 * design, always have reserved bits set. The purpose of the checks is
3839 * to detect reserved bits on non-MMIO SPTEs. i.e. buggy SPTEs.
3841 if (!is_shadow_present_pte(sptes[leaf]))
3844 rsvd_check = &vcpu->arch.mmu->shadow_zero_check;
3846 for (level = root; level >= leaf; level--)
3847 reserved |= is_rsvd_spte(rsvd_check, sptes[level], level);
3850 pr_err("%s: reserved bits set on MMU-present spte, addr 0x%llx, hierarchy:\n",
3852 for (level = root; level >= leaf; level--)
3853 pr_err("------ spte = 0x%llx level = %d, rsvd bits = 0x%llx",
3854 sptes[level], level,
3855 get_rsvd_bits(rsvd_check, sptes[level], level));
3861 static int handle_mmio_page_fault(struct kvm_vcpu *vcpu, u64 addr, bool direct)
3866 if (mmio_info_in_cache(vcpu, addr, direct))
3867 return RET_PF_EMULATE;
3869 reserved = get_mmio_spte(vcpu, addr, &spte);
3870 if (WARN_ON(reserved))
3873 if (is_mmio_spte(spte)) {
3874 gfn_t gfn = get_mmio_spte_gfn(spte);
3875 unsigned int access = get_mmio_spte_access(spte);
3877 if (!check_mmio_spte(vcpu, spte))
3878 return RET_PF_INVALID;
3883 trace_handle_mmio_page_fault(addr, gfn, access);
3884 vcpu_cache_mmio_info(vcpu, addr, gfn, access);
3885 return RET_PF_EMULATE;
3889 * If the page table is zapped by other cpus, let CPU fault again on
3892 return RET_PF_RETRY;
3895 static bool page_fault_handle_page_track(struct kvm_vcpu *vcpu,
3896 struct kvm_page_fault *fault)
3898 if (unlikely(fault->rsvd))
3901 if (!fault->present || !fault->write)
3905 * guest is writing the page which is write tracked which can
3906 * not be fixed by page fault handler.
3908 if (kvm_slot_page_track_is_active(vcpu->kvm, fault->slot, fault->gfn, KVM_PAGE_TRACK_WRITE))
3914 static void shadow_page_table_clear_flood(struct kvm_vcpu *vcpu, gva_t addr)
3916 struct kvm_shadow_walk_iterator iterator;
3919 walk_shadow_page_lockless_begin(vcpu);
3920 for_each_shadow_entry_lockless(vcpu, addr, iterator, spte)
3921 clear_sp_write_flooding_count(iterator.sptep);
3922 walk_shadow_page_lockless_end(vcpu);
3925 static u32 alloc_apf_token(struct kvm_vcpu *vcpu)
3927 /* make sure the token value is not 0 */
3928 u32 id = vcpu->arch.apf.id;
3931 vcpu->arch.apf.id = 1;
3933 return (vcpu->arch.apf.id++ << 12) | vcpu->vcpu_id;
3936 static bool kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
3939 struct kvm_arch_async_pf arch;
3941 arch.token = alloc_apf_token(vcpu);
3943 arch.direct_map = vcpu->arch.mmu->root_role.direct;
3944 arch.cr3 = vcpu->arch.mmu->get_guest_pgd(vcpu);
3946 return kvm_setup_async_pf(vcpu, cr2_or_gpa,
3947 kvm_vcpu_gfn_to_hva(vcpu, gfn), &arch);
3950 void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work)
3954 if ((vcpu->arch.mmu->root_role.direct != work->arch.direct_map) ||
3958 r = kvm_mmu_reload(vcpu);
3962 if (!vcpu->arch.mmu->root_role.direct &&
3963 work->arch.cr3 != vcpu->arch.mmu->get_guest_pgd(vcpu))
3966 kvm_mmu_do_page_fault(vcpu, work->cr2_or_gpa, 0, true);
3969 static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
3971 struct kvm_memory_slot *slot = fault->slot;
3975 * Retry the page fault if the gfn hit a memslot that is being deleted
3976 * or moved. This ensures any existing SPTEs for the old memslot will
3977 * be zapped before KVM inserts a new MMIO SPTE for the gfn.
3979 if (slot && (slot->flags & KVM_MEMSLOT_INVALID))
3980 return RET_PF_RETRY;
3982 if (!kvm_is_visible_memslot(slot)) {
3983 /* Don't expose private memslots to L2. */
3984 if (is_guest_mode(vcpu)) {
3986 fault->pfn = KVM_PFN_NOSLOT;
3987 fault->map_writable = false;
3988 return RET_PF_CONTINUE;
3991 * If the APIC access page exists but is disabled, go directly
3992 * to emulation without caching the MMIO access or creating a
3993 * MMIO SPTE. That way the cache doesn't need to be purged
3994 * when the AVIC is re-enabled.
3996 if (slot && slot->id == APIC_ACCESS_PAGE_PRIVATE_MEMSLOT &&
3997 !kvm_apicv_activated(vcpu->kvm))
3998 return RET_PF_EMULATE;
4002 fault->pfn = __gfn_to_pfn_memslot(slot, fault->gfn, false, &async,
4003 fault->write, &fault->map_writable,
4006 return RET_PF_CONTINUE; /* *pfn has correct page already */
4008 if (!fault->prefetch && kvm_can_do_async_pf(vcpu)) {
4009 trace_kvm_try_async_get_page(fault->addr, fault->gfn);
4010 if (kvm_find_async_pf_gfn(vcpu, fault->gfn)) {
4011 trace_kvm_async_pf_doublefault(fault->addr, fault->gfn);
4012 kvm_make_request(KVM_REQ_APF_HALT, vcpu);
4013 return RET_PF_RETRY;
4014 } else if (kvm_arch_setup_async_pf(vcpu, fault->addr, fault->gfn)) {
4015 return RET_PF_RETRY;
4019 fault->pfn = __gfn_to_pfn_memslot(slot, fault->gfn, false, NULL,
4020 fault->write, &fault->map_writable,
4022 return RET_PF_CONTINUE;
4026 * Returns true if the page fault is stale and needs to be retried, i.e. if the
4027 * root was invalidated by a memslot update or a relevant mmu_notifier fired.
4029 static bool is_page_fault_stale(struct kvm_vcpu *vcpu,
4030 struct kvm_page_fault *fault, int mmu_seq)
4032 struct kvm_mmu_page *sp = to_shadow_page(vcpu->arch.mmu->root.hpa);
4034 /* Special roots, e.g. pae_root, are not backed by shadow pages. */
4035 if (sp && is_obsolete_sp(vcpu->kvm, sp))
4039 * Roots without an associated shadow page are considered invalid if
4040 * there is a pending request to free obsolete roots. The request is
4041 * only a hint that the current root _may_ be obsolete and needs to be
4042 * reloaded, e.g. if the guest frees a PGD that KVM is tracking as a
4043 * previous root, then __kvm_mmu_prepare_zap_page() signals all vCPUs
4044 * to reload even if no vCPU is actively using the root.
4046 if (!sp && kvm_test_request(KVM_REQ_MMU_FREE_OBSOLETE_ROOTS, vcpu))
4049 return fault->slot &&
4050 mmu_notifier_retry_hva(vcpu->kvm, mmu_seq, fault->hva);
4053 static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
4055 bool is_tdp_mmu_fault = is_tdp_mmu(vcpu->arch.mmu);
4057 unsigned long mmu_seq;
4060 fault->gfn = fault->addr >> PAGE_SHIFT;
4061 fault->slot = kvm_vcpu_gfn_to_memslot(vcpu, fault->gfn);
4063 if (page_fault_handle_page_track(vcpu, fault))
4064 return RET_PF_EMULATE;
4066 r = fast_page_fault(vcpu, fault);
4067 if (r != RET_PF_INVALID)
4070 r = mmu_topup_memory_caches(vcpu, false);
4074 mmu_seq = vcpu->kvm->mmu_notifier_seq;
4077 r = kvm_faultin_pfn(vcpu, fault);
4078 if (r != RET_PF_CONTINUE)
4081 r = handle_abnormal_pfn(vcpu, fault, ACC_ALL);
4082 if (r != RET_PF_CONTINUE)
4087 if (is_tdp_mmu_fault)
4088 read_lock(&vcpu->kvm->mmu_lock);
4090 write_lock(&vcpu->kvm->mmu_lock);
4092 if (is_page_fault_stale(vcpu, fault, mmu_seq))
4095 r = make_mmu_pages_available(vcpu);
4099 if (is_tdp_mmu_fault)
4100 r = kvm_tdp_mmu_map(vcpu, fault);
4102 r = __direct_map(vcpu, fault);
4105 if (is_tdp_mmu_fault)
4106 read_unlock(&vcpu->kvm->mmu_lock);
4108 write_unlock(&vcpu->kvm->mmu_lock);
4109 kvm_release_pfn_clean(fault->pfn);
4113 static int nonpaging_page_fault(struct kvm_vcpu *vcpu,
4114 struct kvm_page_fault *fault)
4116 pgprintk("%s: gva %lx error %x\n", __func__, fault->addr, fault->error_code);
4118 /* This path builds a PAE pagetable, we can map 2mb pages at maximum. */
4119 fault->max_level = PG_LEVEL_2M;
4120 return direct_page_fault(vcpu, fault);
4123 int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code,
4124 u64 fault_address, char *insn, int insn_len)
4127 u32 flags = vcpu->arch.apf.host_apf_flags;
4129 #ifndef CONFIG_X86_64
4130 /* A 64-bit CR2 should be impossible on 32-bit KVM. */
4131 if (WARN_ON_ONCE(fault_address >> 32))
4135 vcpu->arch.l1tf_flush_l1d = true;
4137 trace_kvm_page_fault(fault_address, error_code);
4139 if (kvm_event_needs_reinjection(vcpu))
4140 kvm_mmu_unprotect_page_virt(vcpu, fault_address);
4141 r = kvm_mmu_page_fault(vcpu, fault_address, error_code, insn,
4143 } else if (flags & KVM_PV_REASON_PAGE_NOT_PRESENT) {
4144 vcpu->arch.apf.host_apf_flags = 0;
4145 local_irq_disable();
4146 kvm_async_pf_task_wait_schedule(fault_address);
4149 WARN_ONCE(1, "Unexpected host async PF flags: %x\n", flags);
4154 EXPORT_SYMBOL_GPL(kvm_handle_page_fault);
4156 int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
4158 while (fault->max_level > PG_LEVEL_4K) {
4159 int page_num = KVM_PAGES_PER_HPAGE(fault->max_level);
4160 gfn_t base = (fault->addr >> PAGE_SHIFT) & ~(page_num - 1);
4162 if (kvm_mtrr_check_gfn_range_consistency(vcpu, base, page_num))
4168 return direct_page_fault(vcpu, fault);
4171 static void nonpaging_init_context(struct kvm_mmu *context)
4173 context->page_fault = nonpaging_page_fault;
4174 context->gva_to_gpa = nonpaging_gva_to_gpa;
4175 context->sync_page = nonpaging_sync_page;
4176 context->invlpg = NULL;
4179 static inline bool is_root_usable(struct kvm_mmu_root_info *root, gpa_t pgd,
4180 union kvm_mmu_page_role role)
4182 return (role.direct || pgd == root->pgd) &&
4183 VALID_PAGE(root->hpa) &&
4184 role.word == to_shadow_page(root->hpa)->role.word;
4188 * Find out if a previously cached root matching the new pgd/role is available,
4189 * and insert the current root as the MRU in the cache.
4190 * If a matching root is found, it is assigned to kvm_mmu->root and
4192 * If no match is found, kvm_mmu->root is left invalid, the LRU root is
4193 * evicted to make room for the current root, and false is returned.
4195 static bool cached_root_find_and_keep_current(struct kvm *kvm, struct kvm_mmu *mmu,
4197 union kvm_mmu_page_role new_role)
4201 if (is_root_usable(&mmu->root, new_pgd, new_role))
4204 for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) {
4206 * The swaps end up rotating the cache like this:
4207 * C 0 1 2 3 (on entry to the function)
4211 * 3 C 0 1 2 (on exit from the loop)
4213 swap(mmu->root, mmu->prev_roots[i]);
4214 if (is_root_usable(&mmu->root, new_pgd, new_role))
4218 kvm_mmu_free_roots(kvm, mmu, KVM_MMU_ROOT_CURRENT);
4223 * Find out if a previously cached root matching the new pgd/role is available.
4224 * On entry, mmu->root is invalid.
4225 * If a matching root is found, it is assigned to kvm_mmu->root, the LRU entry
4226 * of the cache becomes invalid, and true is returned.
4227 * If no match is found, kvm_mmu->root is left invalid and false is returned.
4229 static bool cached_root_find_without_current(struct kvm *kvm, struct kvm_mmu *mmu,
4231 union kvm_mmu_page_role new_role)
4235 for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++)
4236 if (is_root_usable(&mmu->prev_roots[i], new_pgd, new_role))
4242 swap(mmu->root, mmu->prev_roots[i]);
4243 /* Bubble up the remaining roots. */
4244 for (; i < KVM_MMU_NUM_PREV_ROOTS - 1; i++)
4245 mmu->prev_roots[i] = mmu->prev_roots[i + 1];
4246 mmu->prev_roots[i].hpa = INVALID_PAGE;
4250 static bool fast_pgd_switch(struct kvm *kvm, struct kvm_mmu *mmu,
4251 gpa_t new_pgd, union kvm_mmu_page_role new_role)
4254 * For now, limit the caching to 64-bit hosts+VMs in order to avoid
4255 * having to deal with PDPTEs. We may add support for 32-bit hosts/VMs
4256 * later if necessary.
4258 if (VALID_PAGE(mmu->root.hpa) && !to_shadow_page(mmu->root.hpa))
4259 kvm_mmu_free_roots(kvm, mmu, KVM_MMU_ROOT_CURRENT);
4261 if (VALID_PAGE(mmu->root.hpa))
4262 return cached_root_find_and_keep_current(kvm, mmu, new_pgd, new_role);
4264 return cached_root_find_without_current(kvm, mmu, new_pgd, new_role);
4267 void kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd)
4269 struct kvm_mmu *mmu = vcpu->arch.mmu;
4270 union kvm_mmu_page_role new_role = mmu->root_role;
4272 if (!fast_pgd_switch(vcpu->kvm, mmu, new_pgd, new_role)) {
4273 /* kvm_mmu_ensure_valid_pgd will set up a new root. */
4278 * It's possible that the cached previous root page is obsolete because
4279 * of a change in the MMU generation number. However, changing the
4280 * generation number is accompanied by KVM_REQ_MMU_FREE_OBSOLETE_ROOTS,
4281 * which will free the root set here and allocate a new one.
4283 kvm_make_request(KVM_REQ_LOAD_MMU_PGD, vcpu);
4285 if (force_flush_and_sync_on_reuse) {
4286 kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);
4287 kvm_make_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu);
4291 * The last MMIO access's GVA and GPA are cached in the VCPU. When
4292 * switching to a new CR3, that GVA->GPA mapping may no longer be
4293 * valid. So clear any cached MMIO info even when we don't need to sync
4294 * the shadow page tables.
4296 vcpu_clear_mmio_info(vcpu, MMIO_GVA_ANY);
4299 * If this is a direct root page, it doesn't have a write flooding
4300 * count. Otherwise, clear the write flooding count.
4302 if (!new_role.direct)
4303 __clear_sp_write_flooding_count(
4304 to_shadow_page(vcpu->arch.mmu->root.hpa));
4306 EXPORT_SYMBOL_GPL(kvm_mmu_new_pgd);
4308 static unsigned long get_cr3(struct kvm_vcpu *vcpu)
4310 return kvm_read_cr3(vcpu);
4313 static bool sync_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, gfn_t gfn,
4314 unsigned int access)
4316 if (unlikely(is_mmio_spte(*sptep))) {
4317 if (gfn != get_mmio_spte_gfn(*sptep)) {
4318 mmu_spte_clear_no_track(sptep);
4322 mark_mmio_spte(vcpu, sptep, gfn, access);
4329 #define PTTYPE_EPT 18 /* arbitrary */
4330 #define PTTYPE PTTYPE_EPT
4331 #include "paging_tmpl.h"
4335 #include "paging_tmpl.h"
4339 #include "paging_tmpl.h"
4343 __reset_rsvds_bits_mask(struct rsvd_bits_validate *rsvd_check,
4344 u64 pa_bits_rsvd, int level, bool nx, bool gbpages,
4347 u64 gbpages_bit_rsvd = 0;
4348 u64 nonleaf_bit8_rsvd = 0;
4351 rsvd_check->bad_mt_xwr = 0;
4354 gbpages_bit_rsvd = rsvd_bits(7, 7);
4356 if (level == PT32E_ROOT_LEVEL)
4357 high_bits_rsvd = pa_bits_rsvd & rsvd_bits(0, 62);
4359 high_bits_rsvd = pa_bits_rsvd & rsvd_bits(0, 51);
4361 /* Note, NX doesn't exist in PDPTEs, this is handled below. */
4363 high_bits_rsvd |= rsvd_bits(63, 63);
4366 * Non-leaf PML4Es and PDPEs reserve bit 8 (which would be the G bit for
4367 * leaf entries) on AMD CPUs only.
4370 nonleaf_bit8_rsvd = rsvd_bits(8, 8);
4373 case PT32_ROOT_LEVEL:
4374 /* no rsvd bits for 2 level 4K page table entries */
4375 rsvd_check->rsvd_bits_mask[0][1] = 0;
4376 rsvd_check->rsvd_bits_mask[0][0] = 0;
4377 rsvd_check->rsvd_bits_mask[1][0] =
4378 rsvd_check->rsvd_bits_mask[0][0];
4381 rsvd_check->rsvd_bits_mask[1][1] = 0;
4385 if (is_cpuid_PSE36())
4386 /* 36bits PSE 4MB page */
4387 rsvd_check->rsvd_bits_mask[1][1] = rsvd_bits(17, 21);
4389 /* 32 bits PSE 4MB page */
4390 rsvd_check->rsvd_bits_mask[1][1] = rsvd_bits(13, 21);
4392 case PT32E_ROOT_LEVEL:
4393 rsvd_check->rsvd_bits_mask[0][2] = rsvd_bits(63, 63) |
4396 rsvd_bits(1, 2); /* PDPTE */
4397 rsvd_check->rsvd_bits_mask[0][1] = high_bits_rsvd; /* PDE */
4398 rsvd_check->rsvd_bits_mask[0][0] = high_bits_rsvd; /* PTE */
4399 rsvd_check->rsvd_bits_mask[1][1] = high_bits_rsvd |
4400 rsvd_bits(13, 20); /* large page */
4401 rsvd_check->rsvd_bits_mask[1][0] =
4402 rsvd_check->rsvd_bits_mask[0][0];
4404 case PT64_ROOT_5LEVEL:
4405 rsvd_check->rsvd_bits_mask[0][4] = high_bits_rsvd |
4408 rsvd_check->rsvd_bits_mask[1][4] =
4409 rsvd_check->rsvd_bits_mask[0][4];
4411 case PT64_ROOT_4LEVEL:
4412 rsvd_check->rsvd_bits_mask[0][3] = high_bits_rsvd |
4415 rsvd_check->rsvd_bits_mask[0][2] = high_bits_rsvd |
4417 rsvd_check->rsvd_bits_mask[0][1] = high_bits_rsvd;
4418 rsvd_check->rsvd_bits_mask[0][0] = high_bits_rsvd;
4419 rsvd_check->rsvd_bits_mask[1][3] =
4420 rsvd_check->rsvd_bits_mask[0][3];
4421 rsvd_check->rsvd_bits_mask[1][2] = high_bits_rsvd |
4424 rsvd_check->rsvd_bits_mask[1][1] = high_bits_rsvd |
4425 rsvd_bits(13, 20); /* large page */
4426 rsvd_check->rsvd_bits_mask[1][0] =
4427 rsvd_check->rsvd_bits_mask[0][0];
4432 static bool guest_can_use_gbpages(struct kvm_vcpu *vcpu)
4435 * If TDP is enabled, let the guest use GBPAGES if they're supported in
4436 * hardware. The hardware page walker doesn't let KVM disable GBPAGES,
4437 * i.e. won't treat them as reserved, and KVM doesn't redo the GVA->GPA
4438 * walk for performance and complexity reasons. Not to mention KVM
4439 * _can't_ solve the problem because GVA->GPA walks aren't visible to
4440 * KVM once a TDP translation is installed. Mimic hardware behavior so
4441 * that KVM's is at least consistent, i.e. doesn't randomly inject #PF.
4443 return tdp_enabled ? boot_cpu_has(X86_FEATURE_GBPAGES) :
4444 guest_cpuid_has(vcpu, X86_FEATURE_GBPAGES);
4447 static void reset_guest_rsvds_bits_mask(struct kvm_vcpu *vcpu,
4448 struct kvm_mmu *context)
4450 __reset_rsvds_bits_mask(&context->guest_rsvd_check,
4451 vcpu->arch.reserved_gpa_bits,
4452 context->cpu_role.base.level, is_efer_nx(context),
4453 guest_can_use_gbpages(vcpu),
4454 is_cr4_pse(context),
4455 guest_cpuid_is_amd_or_hygon(vcpu));
4459 __reset_rsvds_bits_mask_ept(struct rsvd_bits_validate *rsvd_check,
4460 u64 pa_bits_rsvd, bool execonly, int huge_page_level)
4462 u64 high_bits_rsvd = pa_bits_rsvd & rsvd_bits(0, 51);
4463 u64 large_1g_rsvd = 0, large_2m_rsvd = 0;
4466 if (huge_page_level < PG_LEVEL_1G)
4467 large_1g_rsvd = rsvd_bits(7, 7);
4468 if (huge_page_level < PG_LEVEL_2M)
4469 large_2m_rsvd = rsvd_bits(7, 7);
4471 rsvd_check->rsvd_bits_mask[0][4] = high_bits_rsvd | rsvd_bits(3, 7);
4472 rsvd_check->rsvd_bits_mask[0][3] = high_bits_rsvd | rsvd_bits(3, 7);
4473 rsvd_check->rsvd_bits_mask[0][2] = high_bits_rsvd | rsvd_bits(3, 6) | large_1g_rsvd;
4474 rsvd_check->rsvd_bits_mask[0][1] = high_bits_rsvd | rsvd_bits(3, 6) | large_2m_rsvd;
4475 rsvd_check->rsvd_bits_mask[0][0] = high_bits_rsvd;
4478 rsvd_check->rsvd_bits_mask[1][4] = rsvd_check->rsvd_bits_mask[0][4];
4479 rsvd_check->rsvd_bits_mask[1][3] = rsvd_check->rsvd_bits_mask[0][3];
4480 rsvd_check->rsvd_bits_mask[1][2] = high_bits_rsvd | rsvd_bits(12, 29) | large_1g_rsvd;
4481 rsvd_check->rsvd_bits_mask[1][1] = high_bits_rsvd | rsvd_bits(12, 20) | large_2m_rsvd;
4482 rsvd_check->rsvd_bits_mask[1][0] = rsvd_check->rsvd_bits_mask[0][0];
4484 bad_mt_xwr = 0xFFull << (2 * 8); /* bits 3..5 must not be 2 */
4485 bad_mt_xwr |= 0xFFull << (3 * 8); /* bits 3..5 must not be 3 */
4486 bad_mt_xwr |= 0xFFull << (7 * 8); /* bits 3..5 must not be 7 */
4487 bad_mt_xwr |= REPEAT_BYTE(1ull << 2); /* bits 0..2 must not be 010 */
4488 bad_mt_xwr |= REPEAT_BYTE(1ull << 6); /* bits 0..2 must not be 110 */
4490 /* bits 0..2 must not be 100 unless VMX capabilities allow it */
4491 bad_mt_xwr |= REPEAT_BYTE(1ull << 4);
4493 rsvd_check->bad_mt_xwr = bad_mt_xwr;
4496 static void reset_rsvds_bits_mask_ept(struct kvm_vcpu *vcpu,
4497 struct kvm_mmu *context, bool execonly, int huge_page_level)
4499 __reset_rsvds_bits_mask_ept(&context->guest_rsvd_check,
4500 vcpu->arch.reserved_gpa_bits, execonly,
4504 static inline u64 reserved_hpa_bits(void)
4506 return rsvd_bits(shadow_phys_bits, 63);
4510 * the page table on host is the shadow page table for the page
4511 * table in guest or amd nested guest, its mmu features completely
4512 * follow the features in guest.
4514 static void reset_shadow_zero_bits_mask(struct kvm_vcpu *vcpu,
4515 struct kvm_mmu *context)
4517 /* @amd adds a check on bit of SPTEs, which KVM shouldn't use anyways. */
4519 /* KVM doesn't use 2-level page tables for the shadow MMU. */
4520 bool is_pse = false;
4521 struct rsvd_bits_validate *shadow_zero_check;
4524 WARN_ON_ONCE(context->root_role.level < PT32E_ROOT_LEVEL);
4526 shadow_zero_check = &context->shadow_zero_check;
4527 __reset_rsvds_bits_mask(shadow_zero_check, reserved_hpa_bits(),
4528 context->root_role.level,
4529 context->root_role.efer_nx,
4530 guest_can_use_gbpages(vcpu), is_pse, is_amd);
4532 if (!shadow_me_mask)
4535 for (i = context->root_role.level; --i >= 0;) {
4537 * So far shadow_me_value is a constant during KVM's life
4538 * time. Bits in shadow_me_value are allowed to be set.
4539 * Bits in shadow_me_mask but not in shadow_me_value are
4540 * not allowed to be set.
4542 shadow_zero_check->rsvd_bits_mask[0][i] |= shadow_me_mask;
4543 shadow_zero_check->rsvd_bits_mask[1][i] |= shadow_me_mask;
4544 shadow_zero_check->rsvd_bits_mask[0][i] &= ~shadow_me_value;
4545 shadow_zero_check->rsvd_bits_mask[1][i] &= ~shadow_me_value;
4550 static inline bool boot_cpu_is_amd(void)
4552 WARN_ON_ONCE(!tdp_enabled);
4553 return shadow_x_mask == 0;
4557 * the direct page table on host, use as much mmu features as
4558 * possible, however, kvm currently does not do execution-protection.
4561 reset_tdp_shadow_zero_bits_mask(struct kvm_mmu *context)
4563 struct rsvd_bits_validate *shadow_zero_check;
4566 shadow_zero_check = &context->shadow_zero_check;
4568 if (boot_cpu_is_amd())
4569 __reset_rsvds_bits_mask(shadow_zero_check, reserved_hpa_bits(),
4570 context->root_role.level, false,
4571 boot_cpu_has(X86_FEATURE_GBPAGES),
4574 __reset_rsvds_bits_mask_ept(shadow_zero_check,
4575 reserved_hpa_bits(), false,
4576 max_huge_page_level);
4578 if (!shadow_me_mask)
4581 for (i = context->root_role.level; --i >= 0;) {
4582 shadow_zero_check->rsvd_bits_mask[0][i] &= ~shadow_me_mask;
4583 shadow_zero_check->rsvd_bits_mask[1][i] &= ~shadow_me_mask;
4588 * as the comments in reset_shadow_zero_bits_mask() except it
4589 * is the shadow page table for intel nested guest.
4592 reset_ept_shadow_zero_bits_mask(struct kvm_mmu *context, bool execonly)
4594 __reset_rsvds_bits_mask_ept(&context->shadow_zero_check,
4595 reserved_hpa_bits(), execonly,
4596 max_huge_page_level);
4599 #define BYTE_MASK(access) \
4600 ((1 & (access) ? 2 : 0) | \
4601 (2 & (access) ? 4 : 0) | \
4602 (3 & (access) ? 8 : 0) | \
4603 (4 & (access) ? 16 : 0) | \
4604 (5 & (access) ? 32 : 0) | \
4605 (6 & (access) ? 64 : 0) | \
4606 (7 & (access) ? 128 : 0))
4609 static void update_permission_bitmask(struct kvm_mmu *mmu, bool ept)
4613 const u8 x = BYTE_MASK(ACC_EXEC_MASK);
4614 const u8 w = BYTE_MASK(ACC_WRITE_MASK);
4615 const u8 u = BYTE_MASK(ACC_USER_MASK);
4617 bool cr4_smep = is_cr4_smep(mmu);
4618 bool cr4_smap = is_cr4_smap(mmu);
4619 bool cr0_wp = is_cr0_wp(mmu);
4620 bool efer_nx = is_efer_nx(mmu);
4622 for (byte = 0; byte < ARRAY_SIZE(mmu->permissions); ++byte) {
4623 unsigned pfec = byte << 1;
4626 * Each "*f" variable has a 1 bit for each UWX value
4627 * that causes a fault with the given PFEC.
4630 /* Faults from writes to non-writable pages */
4631 u8 wf = (pfec & PFERR_WRITE_MASK) ? (u8)~w : 0;
4632 /* Faults from user mode accesses to supervisor pages */
4633 u8 uf = (pfec & PFERR_USER_MASK) ? (u8)~u : 0;
4634 /* Faults from fetches of non-executable pages*/
4635 u8 ff = (pfec & PFERR_FETCH_MASK) ? (u8)~x : 0;
4636 /* Faults from kernel mode fetches of user pages */
4638 /* Faults from kernel mode accesses of user pages */
4642 /* Faults from kernel mode accesses to user pages */
4643 u8 kf = (pfec & PFERR_USER_MASK) ? 0 : u;
4645 /* Not really needed: !nx will cause pte.nx to fault */
4649 /* Allow supervisor writes if !cr0.wp */
4651 wf = (pfec & PFERR_USER_MASK) ? wf : 0;
4653 /* Disallow supervisor fetches of user code if cr4.smep */
4655 smepf = (pfec & PFERR_FETCH_MASK) ? kf : 0;
4658 * SMAP:kernel-mode data accesses from user-mode
4659 * mappings should fault. A fault is considered
4660 * as a SMAP violation if all of the following
4661 * conditions are true:
4662 * - X86_CR4_SMAP is set in CR4
4663 * - A user page is accessed
4664 * - The access is not a fetch
4665 * - The access is supervisor mode
4666 * - If implicit supervisor access or X86_EFLAGS_AC is clear
4668 * Here, we cover the first four conditions.
4669 * The fifth is computed dynamically in permission_fault();
4670 * PFERR_RSVD_MASK bit will be set in PFEC if the access is
4671 * *not* subject to SMAP restrictions.
4674 smapf = (pfec & (PFERR_RSVD_MASK|PFERR_FETCH_MASK)) ? 0 : kf;
4677 mmu->permissions[byte] = ff | uf | wf | smepf | smapf;
4682 * PKU is an additional mechanism by which the paging controls access to
4683 * user-mode addresses based on the value in the PKRU register. Protection
4684 * key violations are reported through a bit in the page fault error code.
4685 * Unlike other bits of the error code, the PK bit is not known at the
4686 * call site of e.g. gva_to_gpa; it must be computed directly in
4687 * permission_fault based on two bits of PKRU, on some machine state (CR4,
4688 * CR0, EFER, CPL), and on other bits of the error code and the page tables.
4690 * In particular the following conditions come from the error code, the
4691 * page tables and the machine state:
4692 * - PK is always zero unless CR4.PKE=1 and EFER.LMA=1
4693 * - PK is always zero if RSVD=1 (reserved bit set) or F=1 (instruction fetch)
4694 * - PK is always zero if U=0 in the page tables
4695 * - PKRU.WD is ignored if CR0.WP=0 and the access is a supervisor access.
4697 * The PKRU bitmask caches the result of these four conditions. The error
4698 * code (minus the P bit) and the page table's U bit form an index into the
4699 * PKRU bitmask. Two bits of the PKRU bitmask are then extracted and ANDed
4700 * with the two bits of the PKRU register corresponding to the protection key.
4701 * For the first three conditions above the bits will be 00, thus masking
4702 * away both AD and WD. For all reads or if the last condition holds, WD
4703 * only will be masked away.
4705 static void update_pkru_bitmask(struct kvm_mmu *mmu)
4712 if (!is_cr4_pke(mmu))
4715 wp = is_cr0_wp(mmu);
4717 for (bit = 0; bit < ARRAY_SIZE(mmu->permissions); ++bit) {
4718 unsigned pfec, pkey_bits;
4719 bool check_pkey, check_write, ff, uf, wf, pte_user;
4722 ff = pfec & PFERR_FETCH_MASK;
4723 uf = pfec & PFERR_USER_MASK;
4724 wf = pfec & PFERR_WRITE_MASK;
4726 /* PFEC.RSVD is replaced by ACC_USER_MASK. */
4727 pte_user = pfec & PFERR_RSVD_MASK;
4730 * Only need to check the access which is not an
4731 * instruction fetch and is to a user page.
4733 check_pkey = (!ff && pte_user);
4735 * write access is controlled by PKRU if it is a
4736 * user access or CR0.WP = 1.
4738 check_write = check_pkey && wf && (uf || wp);
4740 /* PKRU.AD stops both read and write access. */
4741 pkey_bits = !!check_pkey;
4742 /* PKRU.WD stops write access. */
4743 pkey_bits |= (!!check_write) << 1;
4745 mmu->pkru_mask |= (pkey_bits & 3) << pfec;
4749 static void reset_guest_paging_metadata(struct kvm_vcpu *vcpu,
4750 struct kvm_mmu *mmu)
4752 if (!is_cr0_pg(mmu))
4755 reset_guest_rsvds_bits_mask(vcpu, mmu);
4756 update_permission_bitmask(mmu, false);
4757 update_pkru_bitmask(mmu);
4760 static void paging64_init_context(struct kvm_mmu *context)
4762 context->page_fault = paging64_page_fault;
4763 context->gva_to_gpa = paging64_gva_to_gpa;
4764 context->sync_page = paging64_sync_page;
4765 context->invlpg = paging64_invlpg;
4768 static void paging32_init_context(struct kvm_mmu *context)
4770 context->page_fault = paging32_page_fault;
4771 context->gva_to_gpa = paging32_gva_to_gpa;
4772 context->sync_page = paging32_sync_page;
4773 context->invlpg = paging32_invlpg;
4776 static union kvm_cpu_role
4777 kvm_calc_cpu_role(struct kvm_vcpu *vcpu, const struct kvm_mmu_role_regs *regs)
4779 union kvm_cpu_role role = {0};
4781 role.base.access = ACC_ALL;
4782 role.base.smm = is_smm(vcpu);
4783 role.base.guest_mode = is_guest_mode(vcpu);
4786 if (!____is_cr0_pg(regs)) {
4787 role.base.direct = 1;
4791 role.base.efer_nx = ____is_efer_nx(regs);
4792 role.base.cr0_wp = ____is_cr0_wp(regs);
4793 role.base.smep_andnot_wp = ____is_cr4_smep(regs) && !____is_cr0_wp(regs);
4794 role.base.smap_andnot_wp = ____is_cr4_smap(regs) && !____is_cr0_wp(regs);
4795 role.base.has_4_byte_gpte = !____is_cr4_pae(regs);
4797 if (____is_efer_lma(regs))
4798 role.base.level = ____is_cr4_la57(regs) ? PT64_ROOT_5LEVEL
4800 else if (____is_cr4_pae(regs))
4801 role.base.level = PT32E_ROOT_LEVEL;
4803 role.base.level = PT32_ROOT_LEVEL;
4805 role.ext.cr4_smep = ____is_cr4_smep(regs);
4806 role.ext.cr4_smap = ____is_cr4_smap(regs);
4807 role.ext.cr4_pse = ____is_cr4_pse(regs);
4809 /* PKEY and LA57 are active iff long mode is active. */
4810 role.ext.cr4_pke = ____is_efer_lma(regs) && ____is_cr4_pke(regs);
4811 role.ext.cr4_la57 = ____is_efer_lma(regs) && ____is_cr4_la57(regs);
4812 role.ext.efer_lma = ____is_efer_lma(regs);
4816 static inline int kvm_mmu_get_tdp_level(struct kvm_vcpu *vcpu)
4818 /* tdp_root_level is architecture forced level, use it if nonzero */
4820 return tdp_root_level;
4822 /* Use 5-level TDP if and only if it's useful/necessary. */
4823 if (max_tdp_level == 5 && cpuid_maxphyaddr(vcpu) <= 48)
4826 return max_tdp_level;
4829 static union kvm_mmu_page_role
4830 kvm_calc_tdp_mmu_root_page_role(struct kvm_vcpu *vcpu,
4831 union kvm_cpu_role cpu_role)
4833 union kvm_mmu_page_role role = {0};
4835 role.access = ACC_ALL;
4837 role.efer_nx = true;
4838 role.smm = cpu_role.base.smm;
4839 role.guest_mode = cpu_role.base.guest_mode;
4840 role.ad_disabled = !kvm_ad_enabled();
4841 role.level = kvm_mmu_get_tdp_level(vcpu);
4843 role.has_4_byte_gpte = false;
4848 static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu,
4849 union kvm_cpu_role cpu_role)
4851 struct kvm_mmu *context = &vcpu->arch.root_mmu;
4852 union kvm_mmu_page_role root_role = kvm_calc_tdp_mmu_root_page_role(vcpu, cpu_role);
4854 if (cpu_role.as_u64 == context->cpu_role.as_u64 &&
4855 root_role.word == context->root_role.word)
4858 context->cpu_role.as_u64 = cpu_role.as_u64;
4859 context->root_role.word = root_role.word;
4860 context->page_fault = kvm_tdp_page_fault;
4861 context->sync_page = nonpaging_sync_page;
4862 context->invlpg = NULL;
4863 context->get_guest_pgd = get_cr3;
4864 context->get_pdptr = kvm_pdptr_read;
4865 context->inject_page_fault = kvm_inject_page_fault;
4867 if (!is_cr0_pg(context))
4868 context->gva_to_gpa = nonpaging_gva_to_gpa;
4869 else if (is_cr4_pae(context))
4870 context->gva_to_gpa = paging64_gva_to_gpa;
4872 context->gva_to_gpa = paging32_gva_to_gpa;
4874 reset_guest_paging_metadata(vcpu, context);
4875 reset_tdp_shadow_zero_bits_mask(context);
4878 static void shadow_mmu_init_context(struct kvm_vcpu *vcpu, struct kvm_mmu *context,
4879 union kvm_cpu_role cpu_role,
4880 union kvm_mmu_page_role root_role)
4882 if (cpu_role.as_u64 == context->cpu_role.as_u64 &&
4883 root_role.word == context->root_role.word)
4886 context->cpu_role.as_u64 = cpu_role.as_u64;
4887 context->root_role.word = root_role.word;
4889 if (!is_cr0_pg(context))
4890 nonpaging_init_context(context);
4891 else if (is_cr4_pae(context))
4892 paging64_init_context(context);
4894 paging32_init_context(context);
4896 reset_guest_paging_metadata(vcpu, context);
4897 reset_shadow_zero_bits_mask(vcpu, context);
4900 static void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu,
4901 union kvm_cpu_role cpu_role)
4903 struct kvm_mmu *context = &vcpu->arch.root_mmu;
4904 union kvm_mmu_page_role root_role;
4906 root_role = cpu_role.base;
4908 /* KVM uses PAE paging whenever the guest isn't using 64-bit paging. */
4909 root_role.level = max_t(u32, root_role.level, PT32E_ROOT_LEVEL);
4912 * KVM forces EFER.NX=1 when TDP is disabled, reflect it in the MMU role.
4913 * KVM uses NX when TDP is disabled to handle a variety of scenarios,
4914 * notably for huge SPTEs if iTLB multi-hit mitigation is enabled and
4915 * to generate correct permissions for CR0.WP=0/CR4.SMEP=1/EFER.NX=0.
4916 * The iTLB multi-hit workaround can be toggled at any time, so assume
4917 * NX can be used by any non-nested shadow MMU to avoid having to reset
4920 root_role.efer_nx = true;
4922 shadow_mmu_init_context(vcpu, context, cpu_role, root_role);
4925 void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, unsigned long cr0,
4926 unsigned long cr4, u64 efer, gpa_t nested_cr3)
4928 struct kvm_mmu *context = &vcpu->arch.guest_mmu;
4929 struct kvm_mmu_role_regs regs = {
4931 .cr4 = cr4 & ~X86_CR4_PKE,
4934 union kvm_cpu_role cpu_role = kvm_calc_cpu_role(vcpu, ®s);
4935 union kvm_mmu_page_role root_role;
4937 /* NPT requires CR0.PG=1. */
4938 WARN_ON_ONCE(cpu_role.base.direct);
4940 root_role = cpu_role.base;
4941 root_role.level = kvm_mmu_get_tdp_level(vcpu);
4942 if (root_role.level == PT64_ROOT_5LEVEL &&
4943 cpu_role.base.level == PT64_ROOT_4LEVEL)
4944 root_role.passthrough = 1;
4946 shadow_mmu_init_context(vcpu, context, cpu_role, root_role);
4947 kvm_mmu_new_pgd(vcpu, nested_cr3);
4949 EXPORT_SYMBOL_GPL(kvm_init_shadow_npt_mmu);
4951 static union kvm_cpu_role
4952 kvm_calc_shadow_ept_root_page_role(struct kvm_vcpu *vcpu, bool accessed_dirty,
4953 bool execonly, u8 level)
4955 union kvm_cpu_role role = {0};
4958 * KVM does not support SMM transfer monitors, and consequently does not
4959 * support the "entry to SMM" control either. role.base.smm is always 0.
4961 WARN_ON_ONCE(is_smm(vcpu));
4962 role.base.level = level;
4963 role.base.has_4_byte_gpte = false;
4964 role.base.direct = false;
4965 role.base.ad_disabled = !accessed_dirty;
4966 role.base.guest_mode = true;
4967 role.base.access = ACC_ALL;
4970 role.ext.execonly = execonly;
4976 void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
4977 int huge_page_level, bool accessed_dirty,
4980 struct kvm_mmu *context = &vcpu->arch.guest_mmu;
4981 u8 level = vmx_eptp_page_walk_level(new_eptp);
4982 union kvm_cpu_role new_mode =
4983 kvm_calc_shadow_ept_root_page_role(vcpu, accessed_dirty,
4986 if (new_mode.as_u64 != context->cpu_role.as_u64) {
4987 /* EPT, and thus nested EPT, does not consume CR0, CR4, nor EFER. */
4988 context->cpu_role.as_u64 = new_mode.as_u64;
4989 context->root_role.word = new_mode.base.word;
4991 context->page_fault = ept_page_fault;
4992 context->gva_to_gpa = ept_gva_to_gpa;
4993 context->sync_page = ept_sync_page;
4994 context->invlpg = ept_invlpg;
4996 update_permission_bitmask(context, true);
4997 context->pkru_mask = 0;
4998 reset_rsvds_bits_mask_ept(vcpu, context, execonly, huge_page_level);
4999 reset_ept_shadow_zero_bits_mask(context, execonly);
5002 kvm_mmu_new_pgd(vcpu, new_eptp);
5004 EXPORT_SYMBOL_GPL(kvm_init_shadow_ept_mmu);
5006 static void init_kvm_softmmu(struct kvm_vcpu *vcpu,
5007 union kvm_cpu_role cpu_role)
5009 struct kvm_mmu *context = &vcpu->arch.root_mmu;
5011 kvm_init_shadow_mmu(vcpu, cpu_role);
5013 context->get_guest_pgd = get_cr3;
5014 context->get_pdptr = kvm_pdptr_read;
5015 context->inject_page_fault = kvm_inject_page_fault;
5018 static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu,
5019 union kvm_cpu_role new_mode)
5021 struct kvm_mmu *g_context = &vcpu->arch.nested_mmu;
5023 if (new_mode.as_u64 == g_context->cpu_role.as_u64)
5026 g_context->cpu_role.as_u64 = new_mode.as_u64;
5027 g_context->get_guest_pgd = get_cr3;
5028 g_context->get_pdptr = kvm_pdptr_read;
5029 g_context->inject_page_fault = kvm_inject_page_fault;
5032 * L2 page tables are never shadowed, so there is no need to sync
5035 g_context->invlpg = NULL;
5038 * Note that arch.mmu->gva_to_gpa translates l2_gpa to l1_gpa using
5039 * L1's nested page tables (e.g. EPT12). The nested translation
5040 * of l2_gva to l1_gpa is done by arch.nested_mmu.gva_to_gpa using
5041 * L2's page tables as the first level of translation and L1's
5042 * nested page tables as the second level of translation. Basically
5043 * the gva_to_gpa functions between mmu and nested_mmu are swapped.
5045 if (!is_paging(vcpu))
5046 g_context->gva_to_gpa = nonpaging_gva_to_gpa;
5047 else if (is_long_mode(vcpu))
5048 g_context->gva_to_gpa = paging64_gva_to_gpa;
5049 else if (is_pae(vcpu))
5050 g_context->gva_to_gpa = paging64_gva_to_gpa;
5052 g_context->gva_to_gpa = paging32_gva_to_gpa;
5054 reset_guest_paging_metadata(vcpu, g_context);
5057 void kvm_init_mmu(struct kvm_vcpu *vcpu)
5059 struct kvm_mmu_role_regs regs = vcpu_to_role_regs(vcpu);
5060 union kvm_cpu_role cpu_role = kvm_calc_cpu_role(vcpu, ®s);
5062 if (mmu_is_nested(vcpu))
5063 init_kvm_nested_mmu(vcpu, cpu_role);
5064 else if (tdp_enabled)
5065 init_kvm_tdp_mmu(vcpu, cpu_role);
5067 init_kvm_softmmu(vcpu, cpu_role);
5069 EXPORT_SYMBOL_GPL(kvm_init_mmu);
5071 void kvm_mmu_after_set_cpuid(struct kvm_vcpu *vcpu)
5074 * Invalidate all MMU roles to force them to reinitialize as CPUID
5075 * information is factored into reserved bit calculations.
5077 * Correctly handling multiple vCPU models with respect to paging and
5078 * physical address properties) in a single VM would require tracking
5079 * all relevant CPUID information in kvm_mmu_page_role. That is very
5080 * undesirable as it would increase the memory requirements for
5081 * gfn_track (see struct kvm_mmu_page_role comments). For now that
5082 * problem is swept under the rug; KVM's CPUID API is horrific and
5083 * it's all but impossible to solve it without introducing a new API.
5085 vcpu->arch.root_mmu.root_role.word = 0;
5086 vcpu->arch.guest_mmu.root_role.word = 0;
5087 vcpu->arch.nested_mmu.root_role.word = 0;
5088 vcpu->arch.root_mmu.cpu_role.ext.valid = 0;
5089 vcpu->arch.guest_mmu.cpu_role.ext.valid = 0;
5090 vcpu->arch.nested_mmu.cpu_role.ext.valid = 0;
5091 kvm_mmu_reset_context(vcpu);
5094 * Changing guest CPUID after KVM_RUN is forbidden, see the comment in
5095 * kvm_arch_vcpu_ioctl().
5097 KVM_BUG_ON(vcpu->arch.last_vmentry_cpu != -1, vcpu->kvm);
5100 void kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
5102 kvm_mmu_unload(vcpu);
5105 EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
5107 int kvm_mmu_load(struct kvm_vcpu *vcpu)
5111 r = mmu_topup_memory_caches(vcpu, !vcpu->arch.mmu->root_role.direct);
5114 r = mmu_alloc_special_roots(vcpu);
5117 if (vcpu->arch.mmu->root_role.direct)
5118 r = mmu_alloc_direct_roots(vcpu);
5120 r = mmu_alloc_shadow_roots(vcpu);
5124 kvm_mmu_sync_roots(vcpu);
5126 kvm_mmu_load_pgd(vcpu);
5129 * Flush any TLB entries for the new root, the provenance of the root
5130 * is unknown. Even if KVM ensures there are no stale TLB entries
5131 * for a freed root, in theory another hypervisor could have left
5132 * stale entries. Flushing on alloc also allows KVM to skip the TLB
5133 * flush when freeing a root (see kvm_tdp_mmu_put_root()).
5135 static_call(kvm_x86_flush_tlb_current)(vcpu);
5140 void kvm_mmu_unload(struct kvm_vcpu *vcpu)
5142 struct kvm *kvm = vcpu->kvm;
5144 kvm_mmu_free_roots(kvm, &vcpu->arch.root_mmu, KVM_MMU_ROOTS_ALL);
5145 WARN_ON(VALID_PAGE(vcpu->arch.root_mmu.root.hpa));
5146 kvm_mmu_free_roots(kvm, &vcpu->arch.guest_mmu, KVM_MMU_ROOTS_ALL);
5147 WARN_ON(VALID_PAGE(vcpu->arch.guest_mmu.root.hpa));
5148 vcpu_clear_mmio_info(vcpu, MMIO_GVA_ANY);
5151 static bool is_obsolete_root(struct kvm *kvm, hpa_t root_hpa)
5153 struct kvm_mmu_page *sp;
5155 if (!VALID_PAGE(root_hpa))
5159 * When freeing obsolete roots, treat roots as obsolete if they don't
5160 * have an associated shadow page. This does mean KVM will get false
5161 * positives and free roots that don't strictly need to be freed, but
5162 * such false positives are relatively rare:
5164 * (a) only PAE paging and nested NPT has roots without shadow pages
5165 * (b) remote reloads due to a memslot update obsoletes _all_ roots
5166 * (c) KVM doesn't track previous roots for PAE paging, and the guest
5167 * is unlikely to zap an in-use PGD.
5169 sp = to_shadow_page(root_hpa);
5170 return !sp || is_obsolete_sp(kvm, sp);
5173 static void __kvm_mmu_free_obsolete_roots(struct kvm *kvm, struct kvm_mmu *mmu)
5175 unsigned long roots_to_free = 0;
5178 if (is_obsolete_root(kvm, mmu->root.hpa))
5179 roots_to_free |= KVM_MMU_ROOT_CURRENT;
5181 for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) {
5182 if (is_obsolete_root(kvm, mmu->root.hpa))
5183 roots_to_free |= KVM_MMU_ROOT_PREVIOUS(i);
5187 kvm_mmu_free_roots(kvm, mmu, roots_to_free);
5190 void kvm_mmu_free_obsolete_roots(struct kvm_vcpu *vcpu)
5192 __kvm_mmu_free_obsolete_roots(vcpu->kvm, &vcpu->arch.root_mmu);
5193 __kvm_mmu_free_obsolete_roots(vcpu->kvm, &vcpu->arch.guest_mmu);
5196 static bool need_remote_flush(u64 old, u64 new)
5198 if (!is_shadow_present_pte(old))
5200 if (!is_shadow_present_pte(new))
5202 if ((old ^ new) & PT64_BASE_ADDR_MASK)
5204 old ^= shadow_nx_mask;
5205 new ^= shadow_nx_mask;
5206 return (old & ~new & PT64_PERM_MASK) != 0;
5209 static u64 mmu_pte_write_fetch_gpte(struct kvm_vcpu *vcpu, gpa_t *gpa,
5216 * Assume that the pte write on a page table of the same type
5217 * as the current vcpu paging mode since we update the sptes only
5218 * when they have the same mode.
5220 if (is_pae(vcpu) && *bytes == 4) {
5221 /* Handle a 32-bit guest writing two halves of a 64-bit gpte */
5226 if (*bytes == 4 || *bytes == 8) {
5227 r = kvm_vcpu_read_guest_atomic(vcpu, *gpa, &gentry, *bytes);
5236 * If we're seeing too many writes to a page, it may no longer be a page table,
5237 * or we may be forking, in which case it is better to unmap the page.
5239 static bool detect_write_flooding(struct kvm_mmu_page *sp)
5242 * Skip write-flooding detected for the sp whose level is 1, because
5243 * it can become unsync, then the guest page is not write-protected.
5245 if (sp->role.level == PG_LEVEL_4K)
5248 atomic_inc(&sp->write_flooding_count);
5249 return atomic_read(&sp->write_flooding_count) >= 3;
5253 * Misaligned accesses are too much trouble to fix up; also, they usually
5254 * indicate a page is not used as a page table.
5256 static bool detect_write_misaligned(struct kvm_mmu_page *sp, gpa_t gpa,
5259 unsigned offset, pte_size, misaligned;
5261 pgprintk("misaligned: gpa %llx bytes %d role %x\n",
5262 gpa, bytes, sp->role.word);
5264 offset = offset_in_page(gpa);
5265 pte_size = sp->role.has_4_byte_gpte ? 4 : 8;
5268 * Sometimes, the OS only writes the last one bytes to update status
5269 * bits, for example, in linux, andb instruction is used in clear_bit().
5271 if (!(offset & (pte_size - 1)) && bytes == 1)
5274 misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
5275 misaligned |= bytes < 4;
5280 static u64 *get_written_sptes(struct kvm_mmu_page *sp, gpa_t gpa, int *nspte)
5282 unsigned page_offset, quadrant;
5286 page_offset = offset_in_page(gpa);
5287 level = sp->role.level;
5289 if (sp->role.has_4_byte_gpte) {
5290 page_offset <<= 1; /* 32->64 */
5292 * A 32-bit pde maps 4MB while the shadow pdes map
5293 * only 2MB. So we need to double the offset again
5294 * and zap two pdes instead of one.
5296 if (level == PT32_ROOT_LEVEL) {
5297 page_offset &= ~7; /* kill rounding error */
5301 quadrant = page_offset >> PAGE_SHIFT;
5302 page_offset &= ~PAGE_MASK;
5303 if (quadrant != sp->role.quadrant)
5307 spte = &sp->spt[page_offset / sizeof(*spte)];
5311 static void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
5312 const u8 *new, int bytes,
5313 struct kvm_page_track_notifier_node *node)
5315 gfn_t gfn = gpa >> PAGE_SHIFT;
5316 struct kvm_mmu_page *sp;
5317 LIST_HEAD(invalid_list);
5318 u64 entry, gentry, *spte;
5323 * If we don't have indirect shadow pages, it means no page is
5324 * write-protected, so we can exit simply.
5326 if (!READ_ONCE(vcpu->kvm->arch.indirect_shadow_pages))
5329 pgprintk("%s: gpa %llx bytes %d\n", __func__, gpa, bytes);
5332 * No need to care whether allocation memory is successful
5333 * or not since pte prefetch is skipped if it does not have
5334 * enough objects in the cache.
5336 mmu_topup_memory_caches(vcpu, true);
5338 write_lock(&vcpu->kvm->mmu_lock);
5340 gentry = mmu_pte_write_fetch_gpte(vcpu, &gpa, &bytes);
5342 ++vcpu->kvm->stat.mmu_pte_write;
5344 for_each_gfn_valid_sp_with_gptes(vcpu->kvm, sp, gfn) {
5345 if (detect_write_misaligned(sp, gpa, bytes) ||
5346 detect_write_flooding(sp)) {
5347 kvm_mmu_prepare_zap_page(vcpu->kvm, sp, &invalid_list);
5348 ++vcpu->kvm->stat.mmu_flooded;
5352 spte = get_written_sptes(sp, gpa, &npte);
5358 mmu_page_zap_pte(vcpu->kvm, sp, spte, NULL);
5359 if (gentry && sp->role.level != PG_LEVEL_4K)
5360 ++vcpu->kvm->stat.mmu_pde_zapped;
5361 if (need_remote_flush(entry, *spte))
5366 kvm_mmu_remote_flush_or_zap(vcpu->kvm, &invalid_list, flush);
5367 write_unlock(&vcpu->kvm->mmu_lock);
5370 int noinline kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code,
5371 void *insn, int insn_len)
5373 int r, emulation_type = EMULTYPE_PF;
5374 bool direct = vcpu->arch.mmu->root_role.direct;
5376 if (WARN_ON(!VALID_PAGE(vcpu->arch.mmu->root.hpa)))
5377 return RET_PF_RETRY;
5380 if (unlikely(error_code & PFERR_RSVD_MASK)) {
5381 r = handle_mmio_page_fault(vcpu, cr2_or_gpa, direct);
5382 if (r == RET_PF_EMULATE)
5386 if (r == RET_PF_INVALID) {
5387 r = kvm_mmu_do_page_fault(vcpu, cr2_or_gpa,
5388 lower_32_bits(error_code), false);
5389 if (KVM_BUG_ON(r == RET_PF_INVALID, vcpu->kvm))
5395 if (r != RET_PF_EMULATE)
5399 * Before emulating the instruction, check if the error code
5400 * was due to a RO violation while translating the guest page.
5401 * This can occur when using nested virtualization with nested
5402 * paging in both guests. If true, we simply unprotect the page
5403 * and resume the guest.
5405 if (vcpu->arch.mmu->root_role.direct &&
5406 (error_code & PFERR_NESTED_GUEST_PAGE) == PFERR_NESTED_GUEST_PAGE) {
5407 kvm_mmu_unprotect_page(vcpu->kvm, gpa_to_gfn(cr2_or_gpa));
5412 * vcpu->arch.mmu.page_fault returned RET_PF_EMULATE, but we can still
5413 * optimistically try to just unprotect the page and let the processor
5414 * re-execute the instruction that caused the page fault. Do not allow
5415 * retrying MMIO emulation, as it's not only pointless but could also
5416 * cause us to enter an infinite loop because the processor will keep
5417 * faulting on the non-existent MMIO address. Retrying an instruction
5418 * from a nested guest is also pointless and dangerous as we are only
5419 * explicitly shadowing L1's page tables, i.e. unprotecting something
5420 * for L1 isn't going to magically fix whatever issue cause L2 to fail.
5422 if (!mmio_info_in_cache(vcpu, cr2_or_gpa, direct) && !is_guest_mode(vcpu))
5423 emulation_type |= EMULTYPE_ALLOW_RETRY_PF;
5425 return x86_emulate_instruction(vcpu, cr2_or_gpa, emulation_type, insn,
5428 EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);
5430 void kvm_mmu_invalidate_gva(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
5431 gva_t gva, hpa_t root_hpa)
5435 /* It's actually a GPA for vcpu->arch.guest_mmu. */
5436 if (mmu != &vcpu->arch.guest_mmu) {
5437 /* INVLPG on a non-canonical address is a NOP according to the SDM. */
5438 if (is_noncanonical_address(gva, vcpu))
5441 static_call(kvm_x86_flush_tlb_gva)(vcpu, gva);
5447 if (root_hpa == INVALID_PAGE) {
5448 mmu->invlpg(vcpu, gva, mmu->root.hpa);
5451 * INVLPG is required to invalidate any global mappings for the VA,
5452 * irrespective of PCID. Since it would take us roughly similar amount
5453 * of work to determine whether any of the prev_root mappings of the VA
5454 * is marked global, or to just sync it blindly, so we might as well
5455 * just always sync it.
5457 * Mappings not reachable via the current cr3 or the prev_roots will be
5458 * synced when switching to that cr3, so nothing needs to be done here
5461 for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++)
5462 if (VALID_PAGE(mmu->prev_roots[i].hpa))
5463 mmu->invlpg(vcpu, gva, mmu->prev_roots[i].hpa);
5465 mmu->invlpg(vcpu, gva, root_hpa);
5469 void kvm_mmu_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
5471 kvm_mmu_invalidate_gva(vcpu, vcpu->arch.walk_mmu, gva, INVALID_PAGE);
5472 ++vcpu->stat.invlpg;
5474 EXPORT_SYMBOL_GPL(kvm_mmu_invlpg);
5477 void kvm_mmu_invpcid_gva(struct kvm_vcpu *vcpu, gva_t gva, unsigned long pcid)
5479 struct kvm_mmu *mmu = vcpu->arch.mmu;
5480 bool tlb_flush = false;
5483 if (pcid == kvm_get_active_pcid(vcpu)) {
5485 mmu->invlpg(vcpu, gva, mmu->root.hpa);
5489 for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) {
5490 if (VALID_PAGE(mmu->prev_roots[i].hpa) &&
5491 pcid == kvm_get_pcid(vcpu, mmu->prev_roots[i].pgd)) {
5493 mmu->invlpg(vcpu, gva, mmu->prev_roots[i].hpa);
5499 static_call(kvm_x86_flush_tlb_gva)(vcpu, gva);
5501 ++vcpu->stat.invlpg;
5504 * Mappings not reachable via the current cr3 or the prev_roots will be
5505 * synced when switching to that cr3, so nothing needs to be done here
5510 void kvm_configure_mmu(bool enable_tdp, int tdp_forced_root_level,
5511 int tdp_max_root_level, int tdp_huge_page_level)
5513 tdp_enabled = enable_tdp;
5514 tdp_root_level = tdp_forced_root_level;
5515 max_tdp_level = tdp_max_root_level;
5518 * max_huge_page_level reflects KVM's MMU capabilities irrespective
5519 * of kernel support, e.g. KVM may be capable of using 1GB pages when
5520 * the kernel is not. But, KVM never creates a page size greater than
5521 * what is used by the kernel for any given HVA, i.e. the kernel's
5522 * capabilities are ultimately consulted by kvm_mmu_hugepage_adjust().
5525 max_huge_page_level = tdp_huge_page_level;
5526 else if (boot_cpu_has(X86_FEATURE_GBPAGES))
5527 max_huge_page_level = PG_LEVEL_1G;
5529 max_huge_page_level = PG_LEVEL_2M;
5531 EXPORT_SYMBOL_GPL(kvm_configure_mmu);
5533 /* The return value indicates if tlb flush on all vcpus is needed. */
5534 typedef bool (*slot_level_handler) (struct kvm *kvm,
5535 struct kvm_rmap_head *rmap_head,
5536 const struct kvm_memory_slot *slot);
5538 /* The caller should hold mmu-lock before calling this function. */
5539 static __always_inline bool
5540 slot_handle_level_range(struct kvm *kvm, const struct kvm_memory_slot *memslot,
5541 slot_level_handler fn, int start_level, int end_level,
5542 gfn_t start_gfn, gfn_t end_gfn, bool flush_on_yield,
5545 struct slot_rmap_walk_iterator iterator;
5547 for_each_slot_rmap_range(memslot, start_level, end_level, start_gfn,
5548 end_gfn, &iterator) {
5550 flush |= fn(kvm, iterator.rmap, memslot);
5552 if (need_resched() || rwlock_needbreak(&kvm->mmu_lock)) {
5553 if (flush && flush_on_yield) {
5554 kvm_flush_remote_tlbs_with_address(kvm,
5556 iterator.gfn - start_gfn + 1);
5559 cond_resched_rwlock_write(&kvm->mmu_lock);
5566 static __always_inline bool
5567 slot_handle_level(struct kvm *kvm, const struct kvm_memory_slot *memslot,
5568 slot_level_handler fn, int start_level, int end_level,
5569 bool flush_on_yield)
5571 return slot_handle_level_range(kvm, memslot, fn, start_level,
5572 end_level, memslot->base_gfn,
5573 memslot->base_gfn + memslot->npages - 1,
5574 flush_on_yield, false);
5577 static __always_inline bool
5578 slot_handle_level_4k(struct kvm *kvm, const struct kvm_memory_slot *memslot,
5579 slot_level_handler fn, bool flush_on_yield)
5581 return slot_handle_level(kvm, memslot, fn, PG_LEVEL_4K,
5582 PG_LEVEL_4K, flush_on_yield);
5585 static void free_mmu_pages(struct kvm_mmu *mmu)
5587 if (!tdp_enabled && mmu->pae_root)
5588 set_memory_encrypted((unsigned long)mmu->pae_root, 1);
5589 free_page((unsigned long)mmu->pae_root);
5590 free_page((unsigned long)mmu->pml4_root);
5591 free_page((unsigned long)mmu->pml5_root);
5594 static int __kvm_mmu_create(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu)
5599 mmu->root.hpa = INVALID_PAGE;
5601 for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++)
5602 mmu->prev_roots[i] = KVM_MMU_ROOT_INFO_INVALID;
5604 /* vcpu->arch.guest_mmu isn't used when !tdp_enabled. */
5605 if (!tdp_enabled && mmu == &vcpu->arch.guest_mmu)
5609 * When using PAE paging, the four PDPTEs are treated as 'root' pages,
5610 * while the PDP table is a per-vCPU construct that's allocated at MMU
5611 * creation. When emulating 32-bit mode, cr3 is only 32 bits even on
5612 * x86_64. Therefore we need to allocate the PDP table in the first
5613 * 4GB of memory, which happens to fit the DMA32 zone. TDP paging
5614 * generally doesn't use PAE paging and can skip allocating the PDP
5615 * table. The main exception, handled here, is SVM's 32-bit NPT. The
5616 * other exception is for shadowing L1's 32-bit or PAE NPT on 64-bit
5617 * KVM; that horror is handled on-demand by mmu_alloc_special_roots().
5619 if (tdp_enabled && kvm_mmu_get_tdp_level(vcpu) > PT32E_ROOT_LEVEL)
5622 page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_DMA32);
5626 mmu->pae_root = page_address(page);
5629 * CR3 is only 32 bits when PAE paging is used, thus it's impossible to
5630 * get the CPU to treat the PDPTEs as encrypted. Decrypt the page so
5631 * that KVM's writes and the CPU's reads get along. Note, this is
5632 * only necessary when using shadow paging, as 64-bit NPT can get at
5633 * the C-bit even when shadowing 32-bit NPT, and SME isn't supported
5634 * by 32-bit kernels (when KVM itself uses 32-bit NPT).
5637 set_memory_decrypted((unsigned long)mmu->pae_root, 1);
5639 WARN_ON_ONCE(shadow_me_value);
5641 for (i = 0; i < 4; ++i)
5642 mmu->pae_root[i] = INVALID_PAE_ROOT;
5647 int kvm_mmu_create(struct kvm_vcpu *vcpu)
5651 vcpu->arch.mmu_pte_list_desc_cache.kmem_cache = pte_list_desc_cache;
5652 vcpu->arch.mmu_pte_list_desc_cache.gfp_zero = __GFP_ZERO;
5654 vcpu->arch.mmu_page_header_cache.kmem_cache = mmu_page_header_cache;
5655 vcpu->arch.mmu_page_header_cache.gfp_zero = __GFP_ZERO;
5657 vcpu->arch.mmu_shadow_page_cache.gfp_zero = __GFP_ZERO;
5659 vcpu->arch.mmu = &vcpu->arch.root_mmu;
5660 vcpu->arch.walk_mmu = &vcpu->arch.root_mmu;
5662 ret = __kvm_mmu_create(vcpu, &vcpu->arch.guest_mmu);
5666 ret = __kvm_mmu_create(vcpu, &vcpu->arch.root_mmu);
5668 goto fail_allocate_root;
5672 free_mmu_pages(&vcpu->arch.guest_mmu);
5676 #define BATCH_ZAP_PAGES 10
5677 static void kvm_zap_obsolete_pages(struct kvm *kvm)
5679 struct kvm_mmu_page *sp, *node;
5680 int nr_zapped, batch = 0;
5684 list_for_each_entry_safe_reverse(sp, node,
5685 &kvm->arch.active_mmu_pages, link) {
5687 * No obsolete valid page exists before a newly created page
5688 * since active_mmu_pages is a FIFO list.
5690 if (!is_obsolete_sp(kvm, sp))
5694 * Invalid pages should never land back on the list of active
5695 * pages. Skip the bogus page, otherwise we'll get stuck in an
5696 * infinite loop if the page gets put back on the list (again).
5698 if (WARN_ON(sp->role.invalid))
5702 * No need to flush the TLB since we're only zapping shadow
5703 * pages with an obsolete generation number and all vCPUS have
5704 * loaded a new root, i.e. the shadow pages being zapped cannot
5705 * be in active use by the guest.
5707 if (batch >= BATCH_ZAP_PAGES &&
5708 cond_resched_rwlock_write(&kvm->mmu_lock)) {
5713 unstable = __kvm_mmu_prepare_zap_page(kvm, sp,
5714 &kvm->arch.zapped_obsolete_pages, &nr_zapped);
5722 * Kick all vCPUs (via remote TLB flush) before freeing the page tables
5723 * to ensure KVM is not in the middle of a lockless shadow page table
5724 * walk, which may reference the pages. The remote TLB flush itself is
5725 * not required and is simply a convenient way to kick vCPUs as needed.
5726 * KVM performs a local TLB flush when allocating a new root (see
5727 * kvm_mmu_load()), and the reload in the caller ensure no vCPUs are
5728 * running with an obsolete MMU.
5730 kvm_mmu_commit_zap_page(kvm, &kvm->arch.zapped_obsolete_pages);
5734 * Fast invalidate all shadow pages and use lock-break technique
5735 * to zap obsolete pages.
5737 * It's required when memslot is being deleted or VM is being
5738 * destroyed, in these cases, we should ensure that KVM MMU does
5739 * not use any resource of the being-deleted slot or all slots
5740 * after calling the function.
5742 static void kvm_mmu_zap_all_fast(struct kvm *kvm)
5744 lockdep_assert_held(&kvm->slots_lock);
5746 write_lock(&kvm->mmu_lock);
5747 trace_kvm_mmu_zap_all_fast(kvm);
5750 * Toggle mmu_valid_gen between '0' and '1'. Because slots_lock is
5751 * held for the entire duration of zapping obsolete pages, it's
5752 * impossible for there to be multiple invalid generations associated
5753 * with *valid* shadow pages at any given time, i.e. there is exactly
5754 * one valid generation and (at most) one invalid generation.
5756 kvm->arch.mmu_valid_gen = kvm->arch.mmu_valid_gen ? 0 : 1;
5759 * In order to ensure all vCPUs drop their soon-to-be invalid roots,
5760 * invalidating TDP MMU roots must be done while holding mmu_lock for
5761 * write and in the same critical section as making the reload request,
5762 * e.g. before kvm_zap_obsolete_pages() could drop mmu_lock and yield.
5764 if (is_tdp_mmu_enabled(kvm))
5765 kvm_tdp_mmu_invalidate_all_roots(kvm);
5768 * Notify all vcpus to reload its shadow page table and flush TLB.
5769 * Then all vcpus will switch to new shadow page table with the new
5772 * Note: we need to do this under the protection of mmu_lock,
5773 * otherwise, vcpu would purge shadow page but miss tlb flush.
5775 kvm_make_all_cpus_request(kvm, KVM_REQ_MMU_FREE_OBSOLETE_ROOTS);
5777 kvm_zap_obsolete_pages(kvm);
5779 write_unlock(&kvm->mmu_lock);
5782 * Zap the invalidated TDP MMU roots, all SPTEs must be dropped before
5783 * returning to the caller, e.g. if the zap is in response to a memslot
5784 * deletion, mmu_notifier callbacks will be unable to reach the SPTEs
5785 * associated with the deleted memslot once the update completes, and
5786 * Deferring the zap until the final reference to the root is put would
5787 * lead to use-after-free.
5789 if (is_tdp_mmu_enabled(kvm))
5790 kvm_tdp_mmu_zap_invalidated_roots(kvm);
5793 static bool kvm_has_zapped_obsolete_pages(struct kvm *kvm)
5795 return unlikely(!list_empty_careful(&kvm->arch.zapped_obsolete_pages));
5798 static void kvm_mmu_invalidate_zap_pages_in_memslot(struct kvm *kvm,
5799 struct kvm_memory_slot *slot,
5800 struct kvm_page_track_notifier_node *node)
5802 kvm_mmu_zap_all_fast(kvm);
5805 int kvm_mmu_init_vm(struct kvm *kvm)
5807 struct kvm_page_track_notifier_node *node = &kvm->arch.mmu_sp_tracker;
5810 INIT_LIST_HEAD(&kvm->arch.active_mmu_pages);
5811 INIT_LIST_HEAD(&kvm->arch.zapped_obsolete_pages);
5812 INIT_LIST_HEAD(&kvm->arch.lpage_disallowed_mmu_pages);
5813 spin_lock_init(&kvm->arch.mmu_unsync_pages_lock);
5815 r = kvm_mmu_init_tdp_mmu(kvm);
5819 node->track_write = kvm_mmu_pte_write;
5820 node->track_flush_slot = kvm_mmu_invalidate_zap_pages_in_memslot;
5821 kvm_page_track_register_notifier(kvm, node);
5825 void kvm_mmu_uninit_vm(struct kvm *kvm)
5827 struct kvm_page_track_notifier_node *node = &kvm->arch.mmu_sp_tracker;
5829 kvm_page_track_unregister_notifier(kvm, node);
5831 kvm_mmu_uninit_tdp_mmu(kvm);
5834 static bool __kvm_zap_rmaps(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
5836 const struct kvm_memory_slot *memslot;
5837 struct kvm_memslots *slots;
5838 struct kvm_memslot_iter iter;
5843 if (!kvm_memslots_have_rmaps(kvm))
5846 for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
5847 slots = __kvm_memslots(kvm, i);
5849 kvm_for_each_memslot_in_gfn_range(&iter, slots, gfn_start, gfn_end) {
5850 memslot = iter.slot;
5851 start = max(gfn_start, memslot->base_gfn);
5852 end = min(gfn_end, memslot->base_gfn + memslot->npages);
5853 if (WARN_ON_ONCE(start >= end))
5856 flush = slot_handle_level_range(kvm, memslot, kvm_zap_rmapp,
5858 PG_LEVEL_4K, KVM_MAX_HUGEPAGE_LEVEL,
5859 start, end - 1, true, flush);
5867 * Invalidate (zap) SPTEs that cover GFNs from gfn_start and up to gfn_end
5868 * (not including it)
5870 void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
5875 if (WARN_ON_ONCE(gfn_end <= gfn_start))
5878 write_lock(&kvm->mmu_lock);
5880 kvm_inc_notifier_count(kvm, gfn_start, gfn_end);
5882 flush = __kvm_zap_rmaps(kvm, gfn_start, gfn_end);
5884 if (is_tdp_mmu_enabled(kvm)) {
5885 for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++)
5886 flush = kvm_tdp_mmu_zap_leafs(kvm, i, gfn_start,
5887 gfn_end, true, flush);
5891 kvm_flush_remote_tlbs_with_address(kvm, gfn_start,
5892 gfn_end - gfn_start);
5894 kvm_dec_notifier_count(kvm, gfn_start, gfn_end);
5896 write_unlock(&kvm->mmu_lock);
5899 static bool slot_rmap_write_protect(struct kvm *kvm,
5900 struct kvm_rmap_head *rmap_head,
5901 const struct kvm_memory_slot *slot)
5903 return rmap_write_protect(rmap_head, false);
5906 void kvm_mmu_slot_remove_write_access(struct kvm *kvm,
5907 const struct kvm_memory_slot *memslot,
5912 if (kvm_memslots_have_rmaps(kvm)) {
5913 write_lock(&kvm->mmu_lock);
5914 flush = slot_handle_level(kvm, memslot, slot_rmap_write_protect,
5915 start_level, KVM_MAX_HUGEPAGE_LEVEL,
5917 write_unlock(&kvm->mmu_lock);
5920 if (is_tdp_mmu_enabled(kvm)) {
5921 read_lock(&kvm->mmu_lock);
5922 flush |= kvm_tdp_mmu_wrprot_slot(kvm, memslot, start_level);
5923 read_unlock(&kvm->mmu_lock);
5927 * Flush TLBs if any SPTEs had to be write-protected to ensure that
5928 * guest writes are reflected in the dirty bitmap before the memslot
5929 * update completes, i.e. before enabling dirty logging is visible to
5932 * Perform the TLB flush outside the mmu_lock to reduce the amount of
5933 * time the lock is held. However, this does mean that another CPU can
5934 * now grab mmu_lock and encounter a write-protected SPTE while CPUs
5935 * still have a writable mapping for the associated GFN in their TLB.
5937 * This is safe but requires KVM to be careful when making decisions
5938 * based on the write-protection status of an SPTE. Specifically, KVM
5939 * also write-protects SPTEs to monitor changes to guest page tables
5940 * during shadow paging, and must guarantee no CPUs can write to those
5941 * page before the lock is dropped. As mentioned in the previous
5942 * paragraph, a write-protected SPTE is no guarantee that CPU cannot
5943 * perform writes. So to determine if a TLB flush is truly required, KVM
5944 * will clear a separate software-only bit (MMU-writable) and skip the
5945 * flush if-and-only-if this bit was already clear.
5947 * See is_writable_pte() for more details.
5950 kvm_arch_flush_remote_tlbs_memslot(kvm, memslot);
5953 /* Must be called with the mmu_lock held in write-mode. */
5954 void kvm_mmu_try_split_huge_pages(struct kvm *kvm,
5955 const struct kvm_memory_slot *memslot,
5959 if (is_tdp_mmu_enabled(kvm))
5960 kvm_tdp_mmu_try_split_huge_pages(kvm, memslot, start, end,
5961 target_level, false);
5964 * A TLB flush is unnecessary at this point for the same resons as in
5965 * kvm_mmu_slot_try_split_huge_pages().
5969 void kvm_mmu_slot_try_split_huge_pages(struct kvm *kvm,
5970 const struct kvm_memory_slot *memslot,
5973 u64 start = memslot->base_gfn;
5974 u64 end = start + memslot->npages;
5976 if (is_tdp_mmu_enabled(kvm)) {
5977 read_lock(&kvm->mmu_lock);
5978 kvm_tdp_mmu_try_split_huge_pages(kvm, memslot, start, end, target_level, true);
5979 read_unlock(&kvm->mmu_lock);
5983 * No TLB flush is necessary here. KVM will flush TLBs after
5984 * write-protecting and/or clearing dirty on the newly split SPTEs to
5985 * ensure that guest writes are reflected in the dirty log before the
5986 * ioctl to enable dirty logging on this memslot completes. Since the
5987 * split SPTEs retain the write and dirty bits of the huge SPTE, it is
5988 * safe for KVM to decide if a TLB flush is necessary based on the split
5993 static bool kvm_mmu_zap_collapsible_spte(struct kvm *kvm,
5994 struct kvm_rmap_head *rmap_head,
5995 const struct kvm_memory_slot *slot)
5998 struct rmap_iterator iter;
5999 int need_tlb_flush = 0;
6001 struct kvm_mmu_page *sp;
6004 for_each_rmap_spte(rmap_head, &iter, sptep) {
6005 sp = sptep_to_sp(sptep);
6006 pfn = spte_to_pfn(*sptep);
6009 * We cannot do huge page mapping for indirect shadow pages,
6010 * which are found on the last rmap (level = 1) when not using
6011 * tdp; such shadow pages are synced with the page table in
6012 * the guest, and the guest page table is using 4K page size
6013 * mapping if the indirect sp has level = 1.
6015 if (sp->role.direct && !kvm_is_reserved_pfn(pfn) &&
6016 sp->role.level < kvm_mmu_max_mapping_level(kvm, slot, sp->gfn,
6017 pfn, PG_LEVEL_NUM)) {
6018 pte_list_remove(kvm, rmap_head, sptep);
6020 if (kvm_available_flush_tlb_with_range())
6021 kvm_flush_remote_tlbs_with_address(kvm, sp->gfn,
6022 KVM_PAGES_PER_HPAGE(sp->role.level));
6030 return need_tlb_flush;
6033 void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm,
6034 const struct kvm_memory_slot *slot)
6036 if (kvm_memslots_have_rmaps(kvm)) {
6037 write_lock(&kvm->mmu_lock);
6039 * Zap only 4k SPTEs since the legacy MMU only supports dirty
6040 * logging at a 4k granularity and never creates collapsible
6041 * 2m SPTEs during dirty logging.
6043 if (slot_handle_level_4k(kvm, slot, kvm_mmu_zap_collapsible_spte, true))
6044 kvm_arch_flush_remote_tlbs_memslot(kvm, slot);
6045 write_unlock(&kvm->mmu_lock);
6048 if (is_tdp_mmu_enabled(kvm)) {
6049 read_lock(&kvm->mmu_lock);
6050 kvm_tdp_mmu_zap_collapsible_sptes(kvm, slot);
6051 read_unlock(&kvm->mmu_lock);
6055 void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
6056 const struct kvm_memory_slot *memslot)
6059 * All current use cases for flushing the TLBs for a specific memslot
6060 * related to dirty logging, and many do the TLB flush out of mmu_lock.
6061 * The interaction between the various operations on memslot must be
6062 * serialized by slots_locks to ensure the TLB flush from one operation
6063 * is observed by any other operation on the same memslot.
6065 lockdep_assert_held(&kvm->slots_lock);
6066 kvm_flush_remote_tlbs_with_address(kvm, memslot->base_gfn,
6070 void kvm_mmu_slot_leaf_clear_dirty(struct kvm *kvm,
6071 const struct kvm_memory_slot *memslot)
6075 if (kvm_memslots_have_rmaps(kvm)) {
6076 write_lock(&kvm->mmu_lock);
6078 * Clear dirty bits only on 4k SPTEs since the legacy MMU only
6079 * support dirty logging at a 4k granularity.
6081 flush = slot_handle_level_4k(kvm, memslot, __rmap_clear_dirty, false);
6082 write_unlock(&kvm->mmu_lock);
6085 if (is_tdp_mmu_enabled(kvm)) {
6086 read_lock(&kvm->mmu_lock);
6087 flush |= kvm_tdp_mmu_clear_dirty_slot(kvm, memslot);
6088 read_unlock(&kvm->mmu_lock);
6092 * It's also safe to flush TLBs out of mmu lock here as currently this
6093 * function is only used for dirty logging, in which case flushing TLB
6094 * out of mmu lock also guarantees no dirty pages will be lost in
6098 kvm_arch_flush_remote_tlbs_memslot(kvm, memslot);
6101 void kvm_mmu_zap_all(struct kvm *kvm)
6103 struct kvm_mmu_page *sp, *node;
6104 LIST_HEAD(invalid_list);
6107 write_lock(&kvm->mmu_lock);
6109 list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link) {
6110 if (WARN_ON(sp->role.invalid))
6112 if (__kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list, &ign))
6114 if (cond_resched_rwlock_write(&kvm->mmu_lock))
6118 kvm_mmu_commit_zap_page(kvm, &invalid_list);
6120 if (is_tdp_mmu_enabled(kvm))
6121 kvm_tdp_mmu_zap_all(kvm);
6123 write_unlock(&kvm->mmu_lock);
6126 void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen)
6128 WARN_ON(gen & KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS);
6130 gen &= MMIO_SPTE_GEN_MASK;
6133 * Generation numbers are incremented in multiples of the number of
6134 * address spaces in order to provide unique generations across all
6135 * address spaces. Strip what is effectively the address space
6136 * modifier prior to checking for a wrap of the MMIO generation so
6137 * that a wrap in any address space is detected.
6139 gen &= ~((u64)KVM_ADDRESS_SPACE_NUM - 1);
6142 * The very rare case: if the MMIO generation number has wrapped,
6143 * zap all shadow pages.
6145 if (unlikely(gen == 0)) {
6146 kvm_debug_ratelimited("kvm: zapping shadow pages for mmio generation wraparound\n");
6147 kvm_mmu_zap_all_fast(kvm);
6151 static unsigned long
6152 mmu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
6155 int nr_to_scan = sc->nr_to_scan;
6156 unsigned long freed = 0;
6158 mutex_lock(&kvm_lock);
6160 list_for_each_entry(kvm, &vm_list, vm_list) {
6162 LIST_HEAD(invalid_list);
6165 * Never scan more than sc->nr_to_scan VM instances.
6166 * Will not hit this condition practically since we do not try
6167 * to shrink more than one VM and it is very unlikely to see
6168 * !n_used_mmu_pages so many times.
6173 * n_used_mmu_pages is accessed without holding kvm->mmu_lock
6174 * here. We may skip a VM instance errorneosly, but we do not
6175 * want to shrink a VM that only started to populate its MMU
6178 if (!kvm->arch.n_used_mmu_pages &&
6179 !kvm_has_zapped_obsolete_pages(kvm))
6182 idx = srcu_read_lock(&kvm->srcu);
6183 write_lock(&kvm->mmu_lock);
6185 if (kvm_has_zapped_obsolete_pages(kvm)) {
6186 kvm_mmu_commit_zap_page(kvm,
6187 &kvm->arch.zapped_obsolete_pages);
6191 freed = kvm_mmu_zap_oldest_mmu_pages(kvm, sc->nr_to_scan);
6194 write_unlock(&kvm->mmu_lock);
6195 srcu_read_unlock(&kvm->srcu, idx);
6198 * unfair on small ones
6199 * per-vm shrinkers cry out
6200 * sadness comes quickly
6202 list_move_tail(&kvm->vm_list, &vm_list);
6206 mutex_unlock(&kvm_lock);
6210 static unsigned long
6211 mmu_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
6213 return percpu_counter_read_positive(&kvm_total_used_mmu_pages);
6216 static struct shrinker mmu_shrinker = {
6217 .count_objects = mmu_shrink_count,
6218 .scan_objects = mmu_shrink_scan,
6219 .seeks = DEFAULT_SEEKS * 10,
6222 static void mmu_destroy_caches(void)
6224 kmem_cache_destroy(pte_list_desc_cache);
6225 kmem_cache_destroy(mmu_page_header_cache);
6228 static bool get_nx_auto_mode(void)
6230 /* Return true when CPU has the bug, and mitigations are ON */
6231 return boot_cpu_has_bug(X86_BUG_ITLB_MULTIHIT) && !cpu_mitigations_off();
6234 static void __set_nx_huge_pages(bool val)
6236 nx_huge_pages = itlb_multihit_kvm_mitigation = val;
6239 static int set_nx_huge_pages(const char *val, const struct kernel_param *kp)
6241 bool old_val = nx_huge_pages;
6244 /* In "auto" mode deploy workaround only if CPU has the bug. */
6245 if (sysfs_streq(val, "off"))
6247 else if (sysfs_streq(val, "force"))
6249 else if (sysfs_streq(val, "auto"))
6250 new_val = get_nx_auto_mode();
6251 else if (strtobool(val, &new_val) < 0)
6254 __set_nx_huge_pages(new_val);
6256 if (new_val != old_val) {
6259 mutex_lock(&kvm_lock);
6261 list_for_each_entry(kvm, &vm_list, vm_list) {
6262 mutex_lock(&kvm->slots_lock);
6263 kvm_mmu_zap_all_fast(kvm);
6264 mutex_unlock(&kvm->slots_lock);
6266 wake_up_process(kvm->arch.nx_lpage_recovery_thread);
6268 mutex_unlock(&kvm_lock);
6275 * nx_huge_pages needs to be resolved to true/false when kvm.ko is loaded, as
6276 * its default value of -1 is technically undefined behavior for a boolean.
6278 void kvm_mmu_x86_module_init(void)
6280 if (nx_huge_pages == -1)
6281 __set_nx_huge_pages(get_nx_auto_mode());
6285 * The bulk of the MMU initialization is deferred until the vendor module is
6286 * loaded as many of the masks/values may be modified by VMX or SVM, i.e. need
6287 * to be reset when a potentially different vendor module is loaded.
6289 int kvm_mmu_vendor_module_init(void)
6294 * MMU roles use union aliasing which is, generally speaking, an
6295 * undefined behavior. However, we supposedly know how compilers behave
6296 * and the current status quo is unlikely to change. Guardians below are
6297 * supposed to let us know if the assumption becomes false.
6299 BUILD_BUG_ON(sizeof(union kvm_mmu_page_role) != sizeof(u32));
6300 BUILD_BUG_ON(sizeof(union kvm_mmu_extended_role) != sizeof(u32));
6301 BUILD_BUG_ON(sizeof(union kvm_cpu_role) != sizeof(u64));
6303 kvm_mmu_reset_all_pte_masks();
6305 pte_list_desc_cache = kmem_cache_create("pte_list_desc",
6306 sizeof(struct pte_list_desc),
6307 0, SLAB_ACCOUNT, NULL);
6308 if (!pte_list_desc_cache)
6311 mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
6312 sizeof(struct kvm_mmu_page),
6313 0, SLAB_ACCOUNT, NULL);
6314 if (!mmu_page_header_cache)
6317 if (percpu_counter_init(&kvm_total_used_mmu_pages, 0, GFP_KERNEL))
6320 ret = register_shrinker(&mmu_shrinker);
6327 mmu_destroy_caches();
6331 void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
6333 kvm_mmu_unload(vcpu);
6334 free_mmu_pages(&vcpu->arch.root_mmu);
6335 free_mmu_pages(&vcpu->arch.guest_mmu);
6336 mmu_free_memory_caches(vcpu);
6339 void kvm_mmu_vendor_module_exit(void)
6341 mmu_destroy_caches();
6342 percpu_counter_destroy(&kvm_total_used_mmu_pages);
6343 unregister_shrinker(&mmu_shrinker);
6347 * Calculate the effective recovery period, accounting for '0' meaning "let KVM
6348 * select a halving time of 1 hour". Returns true if recovery is enabled.
6350 static bool calc_nx_huge_pages_recovery_period(uint *period)
6353 * Use READ_ONCE to get the params, this may be called outside of the
6354 * param setters, e.g. by the kthread to compute its next timeout.
6356 bool enabled = READ_ONCE(nx_huge_pages);
6357 uint ratio = READ_ONCE(nx_huge_pages_recovery_ratio);
6359 if (!enabled || !ratio)
6362 *period = READ_ONCE(nx_huge_pages_recovery_period_ms);
6364 /* Make sure the period is not less than one second. */
6365 ratio = min(ratio, 3600u);
6366 *period = 60 * 60 * 1000 / ratio;
6371 static int set_nx_huge_pages_recovery_param(const char *val, const struct kernel_param *kp)
6373 bool was_recovery_enabled, is_recovery_enabled;
6374 uint old_period, new_period;
6377 was_recovery_enabled = calc_nx_huge_pages_recovery_period(&old_period);
6379 err = param_set_uint(val, kp);
6383 is_recovery_enabled = calc_nx_huge_pages_recovery_period(&new_period);
6385 if (is_recovery_enabled &&
6386 (!was_recovery_enabled || old_period > new_period)) {
6389 mutex_lock(&kvm_lock);
6391 list_for_each_entry(kvm, &vm_list, vm_list)
6392 wake_up_process(kvm->arch.nx_lpage_recovery_thread);
6394 mutex_unlock(&kvm_lock);
6400 static void kvm_recover_nx_lpages(struct kvm *kvm)
6402 unsigned long nx_lpage_splits = kvm->stat.nx_lpage_splits;
6404 struct kvm_mmu_page *sp;
6406 LIST_HEAD(invalid_list);
6410 rcu_idx = srcu_read_lock(&kvm->srcu);
6411 write_lock(&kvm->mmu_lock);
6414 * Zapping TDP MMU shadow pages, including the remote TLB flush, must
6415 * be done under RCU protection, because the pages are freed via RCU
6420 ratio = READ_ONCE(nx_huge_pages_recovery_ratio);
6421 to_zap = ratio ? DIV_ROUND_UP(nx_lpage_splits, ratio) : 0;
6422 for ( ; to_zap; --to_zap) {
6423 if (list_empty(&kvm->arch.lpage_disallowed_mmu_pages))
6427 * We use a separate list instead of just using active_mmu_pages
6428 * because the number of lpage_disallowed pages is expected to
6429 * be relatively small compared to the total.
6431 sp = list_first_entry(&kvm->arch.lpage_disallowed_mmu_pages,
6432 struct kvm_mmu_page,
6433 lpage_disallowed_link);
6434 WARN_ON_ONCE(!sp->lpage_disallowed);
6435 if (is_tdp_mmu_page(sp)) {
6436 flush |= kvm_tdp_mmu_zap_sp(kvm, sp);
6438 kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
6439 WARN_ON_ONCE(sp->lpage_disallowed);
6442 if (need_resched() || rwlock_needbreak(&kvm->mmu_lock)) {
6443 kvm_mmu_remote_flush_or_zap(kvm, &invalid_list, flush);
6446 cond_resched_rwlock_write(&kvm->mmu_lock);
6452 kvm_mmu_remote_flush_or_zap(kvm, &invalid_list, flush);
6456 write_unlock(&kvm->mmu_lock);
6457 srcu_read_unlock(&kvm->srcu, rcu_idx);
6460 static long get_nx_lpage_recovery_timeout(u64 start_time)
6465 enabled = calc_nx_huge_pages_recovery_period(&period);
6467 return enabled ? start_time + msecs_to_jiffies(period) - get_jiffies_64()
6468 : MAX_SCHEDULE_TIMEOUT;
6471 static int kvm_nx_lpage_recovery_worker(struct kvm *kvm, uintptr_t data)
6474 long remaining_time;
6477 start_time = get_jiffies_64();
6478 remaining_time = get_nx_lpage_recovery_timeout(start_time);
6480 set_current_state(TASK_INTERRUPTIBLE);
6481 while (!kthread_should_stop() && remaining_time > 0) {
6482 schedule_timeout(remaining_time);
6483 remaining_time = get_nx_lpage_recovery_timeout(start_time);
6484 set_current_state(TASK_INTERRUPTIBLE);
6487 set_current_state(TASK_RUNNING);
6489 if (kthread_should_stop())
6492 kvm_recover_nx_lpages(kvm);
6496 int kvm_mmu_post_init_vm(struct kvm *kvm)
6500 err = kvm_vm_create_worker_thread(kvm, kvm_nx_lpage_recovery_worker, 0,
6501 "kvm-nx-lpage-recovery",
6502 &kvm->arch.nx_lpage_recovery_thread);
6504 kthread_unpark(kvm->arch.nx_lpage_recovery_thread);
6509 void kvm_mmu_pre_destroy_vm(struct kvm *kvm)
6511 if (kvm->arch.nx_lpage_recovery_thread)
6512 kthread_stop(kvm->arch.nx_lpage_recovery_thread);