1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __KVM_X86_MMU_H 3 #define __KVM_X86_MMU_H 4 5 #include <linux/kvm_host.h> 6 #include "kvm_cache_regs.h" 7 #include "cpuid.h" 8 9 extern bool __read_mostly enable_mmio_caching; 10 11 #define PT_WRITABLE_SHIFT 1 12 #define PT_USER_SHIFT 2 13 14 #define PT_PRESENT_MASK (1ULL << 0) 15 #define PT_WRITABLE_MASK (1ULL << PT_WRITABLE_SHIFT) 16 #define PT_USER_MASK (1ULL << PT_USER_SHIFT) 17 #define PT_PWT_MASK (1ULL << 3) 18 #define PT_PCD_MASK (1ULL << 4) 19 #define PT_ACCESSED_SHIFT 5 20 #define PT_ACCESSED_MASK (1ULL << PT_ACCESSED_SHIFT) 21 #define PT_DIRTY_SHIFT 6 22 #define PT_DIRTY_MASK (1ULL << PT_DIRTY_SHIFT) 23 #define PT_PAGE_SIZE_SHIFT 7 24 #define PT_PAGE_SIZE_MASK (1ULL << PT_PAGE_SIZE_SHIFT) 25 #define PT_PAT_MASK (1ULL << 7) 26 #define PT_GLOBAL_MASK (1ULL << 8) 27 #define PT64_NX_SHIFT 63 28 #define PT64_NX_MASK (1ULL << PT64_NX_SHIFT) 29 30 #define PT_PAT_SHIFT 7 31 #define PT_DIR_PAT_SHIFT 12 32 #define PT_DIR_PAT_MASK (1ULL << PT_DIR_PAT_SHIFT) 33 34 #define PT64_ROOT_5LEVEL 5 35 #define PT64_ROOT_4LEVEL 4 36 #define PT32_ROOT_LEVEL 2 37 #define PT32E_ROOT_LEVEL 3 38 39 #define KVM_MMU_CR4_ROLE_BITS (X86_CR4_PSE | X86_CR4_PAE | X86_CR4_LA57 | \ 40 X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_PKE) 41 42 #define KVM_MMU_CR0_ROLE_BITS (X86_CR0_PG | X86_CR0_WP) 43 #define KVM_MMU_EFER_ROLE_BITS (EFER_LME | EFER_NX) 44 45 static __always_inline u64 rsvd_bits(int s, int e) 46 { 47 BUILD_BUG_ON(__builtin_constant_p(e) && __builtin_constant_p(s) && e < s); 48 49 if (__builtin_constant_p(e)) 50 BUILD_BUG_ON(e > 63); 51 else 52 e &= 63; 53 54 if (e < s) 55 return 0; 56 57 return ((2ULL << (e - s)) - 1) << s; 58 } 59 60 /* 61 * The number of non-reserved physical address bits irrespective of features 62 * that repurpose legal bits, e.g. MKTME. 63 */ 64 extern u8 __read_mostly shadow_phys_bits; 65 66 static inline gfn_t kvm_mmu_max_gfn(void) 67 { 68 /* 69 * Note that this uses the host MAXPHYADDR, not the guest's. 70 * EPT/NPT cannot support GPAs that would exceed host.MAXPHYADDR; 71 * assuming KVM is running on bare metal, guest accesses beyond 72 * host.MAXPHYADDR will hit a #PF(RSVD) and never cause a vmexit 73 * (either EPT Violation/Misconfig or #NPF), and so KVM will never 74 * install a SPTE for such addresses. If KVM is running as a VM 75 * itself, on the other hand, it might see a MAXPHYADDR that is less 76 * than hardware's real MAXPHYADDR. Using the host MAXPHYADDR 77 * disallows such SPTEs entirely and simplifies the TDP MMU. 78 */ 79 int max_gpa_bits = likely(tdp_enabled) ? shadow_phys_bits : 52; 80 81 return (1ULL << (max_gpa_bits - PAGE_SHIFT)) - 1; 82 } 83 84 static inline u8 kvm_get_shadow_phys_bits(void) 85 { 86 /* 87 * boot_cpu_data.x86_phys_bits is reduced when MKTME or SME are detected 88 * in CPU detection code, but the processor treats those reduced bits as 89 * 'keyID' thus they are not reserved bits. Therefore KVM needs to look at 90 * the physical address bits reported by CPUID. 91 */ 92 if (likely(boot_cpu_data.extended_cpuid_level >= 0x80000008)) 93 return cpuid_eax(0x80000008) & 0xff; 94 95 /* 96 * Quite weird to have VMX or SVM but not MAXPHYADDR; probably a VM with 97 * custom CPUID. Proceed with whatever the kernel found since these features 98 * aren't virtualizable (SME/SEV also require CPUIDs higher than 0x80000008). 99 */ 100 return boot_cpu_data.x86_phys_bits; 101 } 102 103 void kvm_mmu_set_mmio_spte_mask(u64 mmio_value, u64 mmio_mask, u64 access_mask); 104 void kvm_mmu_set_me_spte_mask(u64 me_value, u64 me_mask); 105 void kvm_mmu_set_ept_masks(bool has_ad_bits, bool has_exec_only); 106 107 void kvm_init_mmu(struct kvm_vcpu *vcpu); 108 void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, unsigned long cr0, 109 unsigned long cr4, u64 efer, gpa_t nested_cr3); 110 void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly, 111 int huge_page_level, bool accessed_dirty, 112 gpa_t new_eptp); 113 bool kvm_can_do_async_pf(struct kvm_vcpu *vcpu); 114 int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code, 115 u64 fault_address, char *insn, int insn_len); 116 void __kvm_mmu_refresh_passthrough_bits(struct kvm_vcpu *vcpu, 117 struct kvm_mmu *mmu); 118 119 int kvm_mmu_load(struct kvm_vcpu *vcpu); 120 void kvm_mmu_unload(struct kvm_vcpu *vcpu); 121 void kvm_mmu_free_obsolete_roots(struct kvm_vcpu *vcpu); 122 void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu); 123 void kvm_mmu_sync_prev_roots(struct kvm_vcpu *vcpu); 124 125 static inline int kvm_mmu_reload(struct kvm_vcpu *vcpu) 126 { 127 if (likely(vcpu->arch.mmu->root.hpa != INVALID_PAGE)) 128 return 0; 129 130 return kvm_mmu_load(vcpu); 131 } 132 133 static inline unsigned long kvm_get_pcid(struct kvm_vcpu *vcpu, gpa_t cr3) 134 { 135 BUILD_BUG_ON((X86_CR3_PCID_MASK & PAGE_MASK) != 0); 136 137 return kvm_is_cr4_bit_set(vcpu, X86_CR4_PCIDE) 138 ? cr3 & X86_CR3_PCID_MASK 139 : 0; 140 } 141 142 static inline unsigned long kvm_get_active_pcid(struct kvm_vcpu *vcpu) 143 { 144 return kvm_get_pcid(vcpu, kvm_read_cr3(vcpu)); 145 } 146 147 static inline void kvm_mmu_load_pgd(struct kvm_vcpu *vcpu) 148 { 149 u64 root_hpa = vcpu->arch.mmu->root.hpa; 150 151 if (!VALID_PAGE(root_hpa)) 152 return; 153 154 static_call(kvm_x86_load_mmu_pgd)(vcpu, root_hpa, 155 vcpu->arch.mmu->root_role.level); 156 } 157 158 static inline void kvm_mmu_refresh_passthrough_bits(struct kvm_vcpu *vcpu, 159 struct kvm_mmu *mmu) 160 { 161 /* 162 * When EPT is enabled, KVM may passthrough CR0.WP to the guest, i.e. 163 * @mmu's snapshot of CR0.WP and thus all related paging metadata may 164 * be stale. Refresh CR0.WP and the metadata on-demand when checking 165 * for permission faults. Exempt nested MMUs, i.e. MMUs for shadowing 166 * nEPT and nNPT, as CR0.WP is ignored in both cases. Note, KVM does 167 * need to refresh nested_mmu, a.k.a. the walker used to translate L2 168 * GVAs to GPAs, as that "MMU" needs to honor L2's CR0.WP. 169 */ 170 if (!tdp_enabled || mmu == &vcpu->arch.guest_mmu) 171 return; 172 173 __kvm_mmu_refresh_passthrough_bits(vcpu, mmu); 174 } 175 176 /* 177 * Check if a given access (described through the I/D, W/R and U/S bits of a 178 * page fault error code pfec) causes a permission fault with the given PTE 179 * access rights (in ACC_* format). 180 * 181 * Return zero if the access does not fault; return the page fault error code 182 * if the access faults. 183 */ 184 static inline u8 permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, 185 unsigned pte_access, unsigned pte_pkey, 186 u64 access) 187 { 188 /* strip nested paging fault error codes */ 189 unsigned int pfec = access; 190 unsigned long rflags = static_call(kvm_x86_get_rflags)(vcpu); 191 192 /* 193 * For explicit supervisor accesses, SMAP is disabled if EFLAGS.AC = 1. 194 * For implicit supervisor accesses, SMAP cannot be overridden. 195 * 196 * SMAP works on supervisor accesses only, and not_smap can 197 * be set or not set when user access with neither has any bearing 198 * on the result. 199 * 200 * We put the SMAP checking bit in place of the PFERR_RSVD_MASK bit; 201 * this bit will always be zero in pfec, but it will be one in index 202 * if SMAP checks are being disabled. 203 */ 204 u64 implicit_access = access & PFERR_IMPLICIT_ACCESS; 205 bool not_smap = ((rflags & X86_EFLAGS_AC) | implicit_access) == X86_EFLAGS_AC; 206 int index = (pfec + (not_smap << PFERR_RSVD_BIT)) >> 1; 207 u32 errcode = PFERR_PRESENT_MASK; 208 bool fault; 209 210 kvm_mmu_refresh_passthrough_bits(vcpu, mmu); 211 212 fault = (mmu->permissions[index] >> pte_access) & 1; 213 214 WARN_ON(pfec & (PFERR_PK_MASK | PFERR_RSVD_MASK)); 215 if (unlikely(mmu->pkru_mask)) { 216 u32 pkru_bits, offset; 217 218 /* 219 * PKRU defines 32 bits, there are 16 domains and 2 220 * attribute bits per domain in pkru. pte_pkey is the 221 * index of the protection domain, so pte_pkey * 2 is 222 * is the index of the first bit for the domain. 223 */ 224 pkru_bits = (vcpu->arch.pkru >> (pte_pkey * 2)) & 3; 225 226 /* clear present bit, replace PFEC.RSVD with ACC_USER_MASK. */ 227 offset = (pfec & ~1) + 228 ((pte_access & PT_USER_MASK) << (PFERR_RSVD_BIT - PT_USER_SHIFT)); 229 230 pkru_bits &= mmu->pkru_mask >> offset; 231 errcode |= -pkru_bits & PFERR_PK_MASK; 232 fault |= (pkru_bits != 0); 233 } 234 235 return -(u32)fault & errcode; 236 } 237 238 void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end); 239 240 int kvm_arch_write_log_dirty(struct kvm_vcpu *vcpu); 241 242 int kvm_mmu_post_init_vm(struct kvm *kvm); 243 void kvm_mmu_pre_destroy_vm(struct kvm *kvm); 244 245 static inline bool kvm_shadow_root_allocated(struct kvm *kvm) 246 { 247 /* 248 * Read shadow_root_allocated before related pointers. Hence, threads 249 * reading shadow_root_allocated in any lock context are guaranteed to 250 * see the pointers. Pairs with smp_store_release in 251 * mmu_first_shadow_root_alloc. 252 */ 253 return smp_load_acquire(&kvm->arch.shadow_root_allocated); 254 } 255 256 #ifdef CONFIG_X86_64 257 extern bool tdp_mmu_enabled; 258 #else 259 #define tdp_mmu_enabled false 260 #endif 261 262 static inline bool kvm_memslots_have_rmaps(struct kvm *kvm) 263 { 264 return !tdp_mmu_enabled || kvm_shadow_root_allocated(kvm); 265 } 266 267 static inline gfn_t gfn_to_index(gfn_t gfn, gfn_t base_gfn, int level) 268 { 269 /* KVM_HPAGE_GFN_SHIFT(PG_LEVEL_4K) must be 0. */ 270 return (gfn >> KVM_HPAGE_GFN_SHIFT(level)) - 271 (base_gfn >> KVM_HPAGE_GFN_SHIFT(level)); 272 } 273 274 static inline unsigned long 275 __kvm_mmu_slot_lpages(struct kvm_memory_slot *slot, unsigned long npages, 276 int level) 277 { 278 return gfn_to_index(slot->base_gfn + npages - 1, 279 slot->base_gfn, level) + 1; 280 } 281 282 static inline unsigned long 283 kvm_mmu_slot_lpages(struct kvm_memory_slot *slot, int level) 284 { 285 return __kvm_mmu_slot_lpages(slot, slot->npages, level); 286 } 287 288 static inline void kvm_update_page_stats(struct kvm *kvm, int level, int count) 289 { 290 atomic64_add(count, &kvm->stat.pages[level - 1]); 291 } 292 293 gpa_t translate_nested_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u64 access, 294 struct x86_exception *exception); 295 296 static inline gpa_t kvm_translate_gpa(struct kvm_vcpu *vcpu, 297 struct kvm_mmu *mmu, 298 gpa_t gpa, u64 access, 299 struct x86_exception *exception) 300 { 301 if (mmu != &vcpu->arch.nested_mmu) 302 return gpa; 303 return translate_nested_gpa(vcpu, gpa, access, exception); 304 } 305 #endif 306