1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __KVM_X86_MMU_INTERNAL_H 3 #define __KVM_X86_MMU_INTERNAL_H 4 5 #include <linux/types.h> 6 #include <linux/kvm_host.h> 7 #include <asm/kvm_host.h> 8 9 #undef MMU_DEBUG 10 11 #ifdef MMU_DEBUG 12 extern bool dbg; 13 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) 17 #else 18 #define pgprintk(x...) do { } while (0) 19 #define rmap_printk(x...) do { } while (0) 20 #define MMU_WARN_ON(x) do { } while (0) 21 #endif 22 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)) 28 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)) 31 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)) 34 35 #define __PT_ENT_PER_PAGE(bits_per_level) (1 << (bits_per_level)) 36 37 /* 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. 43 */ 44 #define INVALID_PAE_ROOT 0 45 #define IS_VALID_PAE_ROOT(x) (!!(x)) 46 47 typedef u64 __rcu *tdp_ptep_t; 48 49 struct kvm_mmu_page { 50 /* 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. 53 */ 54 struct list_head link; 55 struct hlist_node hash_link; 56 57 bool tdp_mmu_page; 58 bool unsync; 59 u8 mmu_valid_gen; 60 bool lpage_disallowed; /* Can't be replaced by an equiv large page */ 61 62 /* 63 * The following two entries are used to key the shadow page in the 64 * hash table. 65 */ 66 union kvm_mmu_page_role role; 67 gfn_t gfn; 68 69 u64 *spt; 70 71 /* 72 * Stores the result of the guest translation being shadowed by each 73 * SPTE. KVM shadows two types of guest translations: nGPA -> GPA 74 * (shadow EPT/NPT) and GVA -> GPA (traditional shadow paging). In both 75 * cases the result of the translation is a GPA and a set of access 76 * constraints. 77 * 78 * The GFN is stored in the upper bits (PAGE_SHIFT) and the shadowed 79 * access permissions are stored in the lower bits. Note, for 80 * convenience and uniformity across guests, the access permissions are 81 * stored in KVM format (e.g. ACC_EXEC_MASK) not the raw guest format. 82 */ 83 u64 *shadowed_translation; 84 85 /* Currently serving as active root */ 86 union { 87 int root_count; 88 refcount_t tdp_mmu_root_count; 89 }; 90 unsigned int unsync_children; 91 union { 92 struct kvm_rmap_head parent_ptes; /* rmap pointers to parent sptes */ 93 tdp_ptep_t ptep; 94 }; 95 union { 96 DECLARE_BITMAP(unsync_child_bitmap, 512); 97 struct { 98 struct work_struct tdp_mmu_async_work; 99 void *tdp_mmu_async_data; 100 }; 101 }; 102 103 struct list_head lpage_disallowed_link; 104 #ifdef CONFIG_X86_32 105 /* 106 * Used out of the mmu-lock to avoid reading spte values while an 107 * update is in progress; see the comments in __get_spte_lockless(). 108 */ 109 int clear_spte_count; 110 #endif 111 112 /* Number of writes since the last time traversal visited this page. */ 113 atomic_t write_flooding_count; 114 115 #ifdef CONFIG_X86_64 116 /* Used for freeing the page asynchronously if it is a TDP MMU page. */ 117 struct rcu_head rcu_head; 118 #endif 119 }; 120 121 extern struct kmem_cache *mmu_page_header_cache; 122 123 static inline struct kvm_mmu_page *to_shadow_page(hpa_t shadow_page) 124 { 125 struct page *page = pfn_to_page(shadow_page >> PAGE_SHIFT); 126 127 return (struct kvm_mmu_page *)page_private(page); 128 } 129 130 static inline struct kvm_mmu_page *sptep_to_sp(u64 *sptep) 131 { 132 return to_shadow_page(__pa(sptep)); 133 } 134 135 static inline int kvm_mmu_role_as_id(union kvm_mmu_page_role role) 136 { 137 return role.smm ? 1 : 0; 138 } 139 140 static inline int kvm_mmu_page_as_id(struct kvm_mmu_page *sp) 141 { 142 return kvm_mmu_role_as_id(sp->role); 143 } 144 145 static inline bool kvm_mmu_page_ad_need_write_protect(struct kvm_mmu_page *sp) 146 { 147 /* 148 * When using the EPT page-modification log, the GPAs in the CPU dirty 149 * log would come from L2 rather than L1. Therefore, we need to rely 150 * on write protection to record dirty pages, which bypasses PML, since 151 * writes now result in a vmexit. Note, the check on CPU dirty logging 152 * being enabled is mandatory as the bits used to denote WP-only SPTEs 153 * are reserved for PAE paging (32-bit KVM). 154 */ 155 return kvm_x86_ops.cpu_dirty_log_size && sp->role.guest_mode; 156 } 157 158 int mmu_try_to_unsync_pages(struct kvm *kvm, const struct kvm_memory_slot *slot, 159 gfn_t gfn, bool can_unsync, bool prefetch); 160 161 void kvm_mmu_gfn_disallow_lpage(const struct kvm_memory_slot *slot, gfn_t gfn); 162 void kvm_mmu_gfn_allow_lpage(const struct kvm_memory_slot *slot, gfn_t gfn); 163 bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm, 164 struct kvm_memory_slot *slot, u64 gfn, 165 int min_level); 166 void kvm_flush_remote_tlbs_with_address(struct kvm *kvm, 167 u64 start_gfn, u64 pages); 168 unsigned int pte_list_count(struct kvm_rmap_head *rmap_head); 169 170 extern int nx_huge_pages; 171 static inline bool is_nx_huge_page_enabled(struct kvm *kvm) 172 { 173 return READ_ONCE(nx_huge_pages) && !kvm->arch.disable_nx_huge_pages; 174 } 175 176 struct kvm_page_fault { 177 /* arguments to kvm_mmu_do_page_fault. */ 178 const gpa_t addr; 179 const u32 error_code; 180 const bool prefetch; 181 182 /* Derived from error_code. */ 183 const bool exec; 184 const bool write; 185 const bool present; 186 const bool rsvd; 187 const bool user; 188 189 /* Derived from mmu and global state. */ 190 const bool is_tdp; 191 const bool nx_huge_page_workaround_enabled; 192 193 /* 194 * Whether a >4KB mapping can be created or is forbidden due to NX 195 * hugepages. 196 */ 197 bool huge_page_disallowed; 198 199 /* 200 * Maximum page size that can be created for this fault; input to 201 * FNAME(fetch), __direct_map and kvm_tdp_mmu_map. 202 */ 203 u8 max_level; 204 205 /* 206 * Page size that can be created based on the max_level and the 207 * page size used by the host mapping. 208 */ 209 u8 req_level; 210 211 /* 212 * Page size that will be created based on the req_level and 213 * huge_page_disallowed. 214 */ 215 u8 goal_level; 216 217 /* Shifted addr, or result of guest page table walk if addr is a gva. */ 218 gfn_t gfn; 219 220 /* The memslot containing gfn. May be NULL. */ 221 struct kvm_memory_slot *slot; 222 223 /* Outputs of kvm_faultin_pfn. */ 224 kvm_pfn_t pfn; 225 hva_t hva; 226 bool map_writable; 227 }; 228 229 int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault); 230 231 /* 232 * Return values of handle_mmio_page_fault(), mmu.page_fault(), fast_page_fault(), 233 * and of course kvm_mmu_do_page_fault(). 234 * 235 * RET_PF_CONTINUE: So far, so good, keep handling the page fault. 236 * RET_PF_RETRY: let CPU fault again on the address. 237 * RET_PF_EMULATE: mmio page fault, emulate the instruction directly. 238 * RET_PF_INVALID: the spte is invalid, let the real page fault path update it. 239 * RET_PF_FIXED: The faulting entry has been fixed. 240 * RET_PF_SPURIOUS: The faulting entry was already fixed, e.g. by another vCPU. 241 * 242 * Any names added to this enum should be exported to userspace for use in 243 * tracepoints via TRACE_DEFINE_ENUM() in mmutrace.h 244 * 245 * Note, all values must be greater than or equal to zero so as not to encroach 246 * on -errno return values. Somewhat arbitrarily use '0' for CONTINUE, which 247 * will allow for efficient machine code when checking for CONTINUE, e.g. 248 * "TEST %rax, %rax, JNZ", as all "stop!" values are non-zero. 249 */ 250 enum { 251 RET_PF_CONTINUE = 0, 252 RET_PF_RETRY, 253 RET_PF_EMULATE, 254 RET_PF_INVALID, 255 RET_PF_FIXED, 256 RET_PF_SPURIOUS, 257 }; 258 259 static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, 260 u32 err, bool prefetch) 261 { 262 struct kvm_page_fault fault = { 263 .addr = cr2_or_gpa, 264 .error_code = err, 265 .exec = err & PFERR_FETCH_MASK, 266 .write = err & PFERR_WRITE_MASK, 267 .present = err & PFERR_PRESENT_MASK, 268 .rsvd = err & PFERR_RSVD_MASK, 269 .user = err & PFERR_USER_MASK, 270 .prefetch = prefetch, 271 .is_tdp = likely(vcpu->arch.mmu->page_fault == kvm_tdp_page_fault), 272 .nx_huge_page_workaround_enabled = 273 is_nx_huge_page_enabled(vcpu->kvm), 274 275 .max_level = KVM_MAX_HUGEPAGE_LEVEL, 276 .req_level = PG_LEVEL_4K, 277 .goal_level = PG_LEVEL_4K, 278 }; 279 int r; 280 281 /* 282 * Async #PF "faults", a.k.a. prefetch faults, are not faults from the 283 * guest perspective and have already been counted at the time of the 284 * original fault. 285 */ 286 if (!prefetch) 287 vcpu->stat.pf_taken++; 288 289 if (IS_ENABLED(CONFIG_RETPOLINE) && fault.is_tdp) 290 r = kvm_tdp_page_fault(vcpu, &fault); 291 else 292 r = vcpu->arch.mmu->page_fault(vcpu, &fault); 293 294 /* 295 * Similar to above, prefetch faults aren't truly spurious, and the 296 * async #PF path doesn't do emulation. Do count faults that are fixed 297 * by the async #PF handler though, otherwise they'll never be counted. 298 */ 299 if (r == RET_PF_FIXED) 300 vcpu->stat.pf_fixed++; 301 else if (prefetch) 302 ; 303 else if (r == RET_PF_EMULATE) 304 vcpu->stat.pf_emulate++; 305 else if (r == RET_PF_SPURIOUS) 306 vcpu->stat.pf_spurious++; 307 return r; 308 } 309 310 int kvm_mmu_max_mapping_level(struct kvm *kvm, 311 const struct kvm_memory_slot *slot, gfn_t gfn, 312 int max_level); 313 void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault); 314 void disallowed_hugepage_adjust(struct kvm_page_fault *fault, u64 spte, int cur_level); 315 316 void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc); 317 318 void account_huge_nx_page(struct kvm *kvm, struct kvm_mmu_page *sp); 319 void unaccount_huge_nx_page(struct kvm *kvm, struct kvm_mmu_page *sp); 320 321 #endif /* __KVM_X86_MMU_INTERNAL_H */ 322