1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __KVM_X86_MMU_INTERNAL_H
3 #define __KVM_X86_MMU_INTERNAL_H
5 #include <linux/types.h>
6 #include <linux/kvm_host.h>
7 #include <asm/kvm_host.h>
14 #define pgprintk(x...) do { if (dbg) printk(x); } while (0)
15 #define rmap_printk(fmt, args...) do { if (dbg) printk("%s: " fmt, __func__, ## args); } while (0)
16 #define MMU_WARN_ON(x) WARN_ON(x)
18 #define pgprintk(x...) do { } while (0)
19 #define rmap_printk(x...) do { } while (0)
20 #define MMU_WARN_ON(x) do { } while (0)
23 /* Page table builder macros common to shadow (host) PTEs and guest PTEs. */
24 #define __PT_LEVEL_SHIFT(level, bits_per_level) \
25 (PAGE_SHIFT + ((level) - 1) * (bits_per_level))
26 #define __PT_INDEX(address, level, bits_per_level) \
27 (((address) >> __PT_LEVEL_SHIFT(level, bits_per_level)) & ((1 << (bits_per_level)) - 1))
29 #define __PT_LVL_ADDR_MASK(base_addr_mask, level, bits_per_level) \
30 ((base_addr_mask) & ~((1ULL << (PAGE_SHIFT + (((level) - 1) * (bits_per_level)))) - 1))
32 #define __PT_LVL_OFFSET_MASK(base_addr_mask, level, bits_per_level) \
33 ((base_addr_mask) & ((1ULL << (PAGE_SHIFT + (((level) - 1) * (bits_per_level)))) - 1))
35 #define __PT_ENT_PER_PAGE(bits_per_level) (1 << (bits_per_level))
38 * Unlike regular MMU roots, PAE "roots", a.k.a. PDPTEs/PDPTRs, have a PRESENT
39 * bit, and thus are guaranteed to be non-zero when valid. And, when a guest
40 * PDPTR is !PRESENT, its corresponding PAE root cannot be set to INVALID_PAGE,
41 * as the CPU would treat that as PRESENT PDPTR with reserved bits set. Use
42 * '0' instead of INVALID_PAGE to indicate an invalid PAE root.
44 #define INVALID_PAE_ROOT 0
45 #define IS_VALID_PAE_ROOT(x) (!!(x))
47 typedef u64 __rcu *tdp_ptep_t;
51 * Note, "link" through "spt" fit in a single 64 byte cache line on
52 * 64-bit kernels, keep it that way unless there's a reason not to.
54 struct list_head link;
55 struct hlist_node hash_link;
62 * The shadow page can't be replaced by an equivalent huge page
63 * because it is being used to map an executable page in the guest
64 * and the NX huge page mitigation is enabled.
66 bool nx_huge_page_disallowed;
69 * The following two entries are used to key the shadow page in the
72 union kvm_mmu_page_role role;
78 * Stores the result of the guest translation being shadowed by each
79 * SPTE. KVM shadows two types of guest translations: nGPA -> GPA
80 * (shadow EPT/NPT) and GVA -> GPA (traditional shadow paging). In both
81 * cases the result of the translation is a GPA and a set of access
84 * The GFN is stored in the upper bits (PAGE_SHIFT) and the shadowed
85 * access permissions are stored in the lower bits. Note, for
86 * convenience and uniformity across guests, the access permissions are
87 * stored in KVM format (e.g. ACC_EXEC_MASK) not the raw guest format.
89 u64 *shadowed_translation;
91 /* Currently serving as active root */
94 refcount_t tdp_mmu_root_count;
96 unsigned int unsync_children;
98 struct kvm_rmap_head parent_ptes; /* rmap pointers to parent sptes */
102 DECLARE_BITMAP(unsync_child_bitmap, 512);
104 struct work_struct tdp_mmu_async_work;
105 void *tdp_mmu_async_data;
110 * Tracks shadow pages that, if zapped, would allow KVM to create an NX
111 * huge page. A shadow page will have nx_huge_page_disallowed set but
112 * not be on the list if a huge page is disallowed for other reasons,
113 * e.g. because KVM is shadowing a PTE at the same gfn, the memslot
114 * isn't properly aligned, etc...
116 struct list_head possible_nx_huge_page_link;
119 * Used out of the mmu-lock to avoid reading spte values while an
120 * update is in progress; see the comments in __get_spte_lockless().
122 int clear_spte_count;
125 /* Number of writes since the last time traversal visited this page. */
126 atomic_t write_flooding_count;
129 /* Used for freeing the page asynchronously if it is a TDP MMU page. */
130 struct rcu_head rcu_head;
134 extern struct kmem_cache *mmu_page_header_cache;
136 static inline int kvm_mmu_role_as_id(union kvm_mmu_page_role role)
138 return role.smm ? 1 : 0;
141 static inline int kvm_mmu_page_as_id(struct kvm_mmu_page *sp)
143 return kvm_mmu_role_as_id(sp->role);
146 static inline bool kvm_mmu_page_ad_need_write_protect(struct kvm_mmu_page *sp)
149 * When using the EPT page-modification log, the GPAs in the CPU dirty
150 * log would come from L2 rather than L1. Therefore, we need to rely
151 * on write protection to record dirty pages, which bypasses PML, since
152 * writes now result in a vmexit. Note, the check on CPU dirty logging
153 * being enabled is mandatory as the bits used to denote WP-only SPTEs
154 * are reserved for PAE paging (32-bit KVM).
156 return kvm_x86_ops.cpu_dirty_log_size && sp->role.guest_mode;
159 static inline gfn_t gfn_round_for_level(gfn_t gfn, int level)
161 return gfn & -KVM_PAGES_PER_HPAGE(level);
164 int mmu_try_to_unsync_pages(struct kvm *kvm, const struct kvm_memory_slot *slot,
165 gfn_t gfn, bool can_unsync, bool prefetch);
167 void kvm_mmu_gfn_disallow_lpage(const struct kvm_memory_slot *slot, gfn_t gfn);
168 void kvm_mmu_gfn_allow_lpage(const struct kvm_memory_slot *slot, gfn_t gfn);
169 bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
170 struct kvm_memory_slot *slot, u64 gfn,
173 void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t start_gfn,
176 /* Flush the given page (huge or not) of guest memory. */
177 static inline void kvm_flush_remote_tlbs_gfn(struct kvm *kvm, gfn_t gfn, int level)
179 kvm_flush_remote_tlbs_range(kvm, gfn_round_for_level(gfn, level),
180 KVM_PAGES_PER_HPAGE(level));
183 unsigned int pte_list_count(struct kvm_rmap_head *rmap_head);
185 extern int nx_huge_pages;
186 static inline bool is_nx_huge_page_enabled(struct kvm *kvm)
188 return READ_ONCE(nx_huge_pages) && !kvm->arch.disable_nx_huge_pages;
191 struct kvm_page_fault {
192 /* arguments to kvm_mmu_do_page_fault. */
194 const u32 error_code;
197 /* Derived from error_code. */
204 /* Derived from mmu and global state. */
206 const bool nx_huge_page_workaround_enabled;
209 * Whether a >4KB mapping can be created or is forbidden due to NX
212 bool huge_page_disallowed;
215 * Maximum page size that can be created for this fault; input to
216 * FNAME(fetch), direct_map() and kvm_tdp_mmu_map().
221 * Page size that can be created based on the max_level and the
222 * page size used by the host mapping.
227 * Page size that will be created based on the req_level and
228 * huge_page_disallowed.
232 /* Shifted addr, or result of guest page table walk if addr is a gva. */
235 /* The memslot containing gfn. May be NULL. */
236 struct kvm_memory_slot *slot;
238 /* Outputs of kvm_faultin_pfn. */
239 unsigned long mmu_seq;
245 * Indicates the guest is trying to write a gfn that contains one or
246 * more of the PTEs used to translate the write itself, i.e. the access
247 * is changing its own translation in the guest page tables.
249 bool write_fault_to_shadow_pgtable;
252 int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault);
255 * Return values of handle_mmio_page_fault(), mmu.page_fault(), fast_page_fault(),
256 * and of course kvm_mmu_do_page_fault().
258 * RET_PF_CONTINUE: So far, so good, keep handling the page fault.
259 * RET_PF_RETRY: let CPU fault again on the address.
260 * RET_PF_EMULATE: mmio page fault, emulate the instruction directly.
261 * RET_PF_INVALID: the spte is invalid, let the real page fault path update it.
262 * RET_PF_FIXED: The faulting entry has been fixed.
263 * RET_PF_SPURIOUS: The faulting entry was already fixed, e.g. by another vCPU.
265 * Any names added to this enum should be exported to userspace for use in
266 * tracepoints via TRACE_DEFINE_ENUM() in mmutrace.h
268 * Note, all values must be greater than or equal to zero so as not to encroach
269 * on -errno return values. Somewhat arbitrarily use '0' for CONTINUE, which
270 * will allow for efficient machine code when checking for CONTINUE, e.g.
271 * "TEST %rax, %rax, JNZ", as all "stop!" values are non-zero.
282 static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
283 u32 err, bool prefetch, int *emulation_type)
285 struct kvm_page_fault fault = {
288 .exec = err & PFERR_FETCH_MASK,
289 .write = err & PFERR_WRITE_MASK,
290 .present = err & PFERR_PRESENT_MASK,
291 .rsvd = err & PFERR_RSVD_MASK,
292 .user = err & PFERR_USER_MASK,
293 .prefetch = prefetch,
294 .is_tdp = likely(vcpu->arch.mmu->page_fault == kvm_tdp_page_fault),
295 .nx_huge_page_workaround_enabled =
296 is_nx_huge_page_enabled(vcpu->kvm),
298 .max_level = KVM_MAX_HUGEPAGE_LEVEL,
299 .req_level = PG_LEVEL_4K,
300 .goal_level = PG_LEVEL_4K,
304 if (vcpu->arch.mmu->root_role.direct) {
305 fault.gfn = fault.addr >> PAGE_SHIFT;
306 fault.slot = kvm_vcpu_gfn_to_memslot(vcpu, fault.gfn);
310 * Async #PF "faults", a.k.a. prefetch faults, are not faults from the
311 * guest perspective and have already been counted at the time of the
315 vcpu->stat.pf_taken++;
317 if (IS_ENABLED(CONFIG_RETPOLINE) && fault.is_tdp)
318 r = kvm_tdp_page_fault(vcpu, &fault);
320 r = vcpu->arch.mmu->page_fault(vcpu, &fault);
322 if (fault.write_fault_to_shadow_pgtable && emulation_type)
323 *emulation_type |= EMULTYPE_WRITE_PF_TO_SP;
326 * Similar to above, prefetch faults aren't truly spurious, and the
327 * async #PF path doesn't do emulation. Do count faults that are fixed
328 * by the async #PF handler though, otherwise they'll never be counted.
330 if (r == RET_PF_FIXED)
331 vcpu->stat.pf_fixed++;
334 else if (r == RET_PF_EMULATE)
335 vcpu->stat.pf_emulate++;
336 else if (r == RET_PF_SPURIOUS)
337 vcpu->stat.pf_spurious++;
341 int kvm_mmu_max_mapping_level(struct kvm *kvm,
342 const struct kvm_memory_slot *slot, gfn_t gfn,
344 void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault);
345 void disallowed_hugepage_adjust(struct kvm_page_fault *fault, u64 spte, int cur_level);
347 void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc);
349 void track_possible_nx_huge_page(struct kvm *kvm, struct kvm_mmu_page *sp);
350 void untrack_possible_nx_huge_page(struct kvm *kvm, struct kvm_mmu_page *sp);
352 #endif /* __KVM_X86_MMU_INTERNAL_H */