1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef ARCH_X86_KVM_REVERSE_CPUID_H 3 #define ARCH_X86_KVM_REVERSE_CPUID_H 4 5 #include <uapi/asm/kvm.h> 6 #include <asm/cpufeature.h> 7 #include <asm/cpufeatures.h> 8 9 /* 10 * Hardware-defined CPUID leafs that are either scattered by the kernel or are 11 * unknown to the kernel, but need to be directly used by KVM. Note, these 12 * word values conflict with the kernel's "bug" caps, but KVM doesn't use those. 13 */ 14 enum kvm_only_cpuid_leafs { 15 CPUID_12_EAX = NCAPINTS, 16 CPUID_7_1_EDX, 17 CPUID_8000_0007_EDX, 18 CPUID_8000_0022_EAX, 19 CPUID_7_2_EDX, 20 NR_KVM_CPU_CAPS, 21 22 NKVMCAPINTS = NR_KVM_CPU_CAPS - NCAPINTS, 23 }; 24 25 /* 26 * Define a KVM-only feature flag. 27 * 28 * For features that are scattered by cpufeatures.h, __feature_translate() also 29 * needs to be updated to translate the kernel-defined feature into the 30 * KVM-defined feature. 31 * 32 * For features that are 100% KVM-only, i.e. not defined by cpufeatures.h, 33 * forego the intermediate KVM_X86_FEATURE and directly define X86_FEATURE_* so 34 * that X86_FEATURE_* can be used in KVM. No __feature_translate() handling is 35 * needed in this case. 36 */ 37 #define KVM_X86_FEATURE(w, f) ((w)*32 + (f)) 38 39 /* Intel-defined SGX sub-features, CPUID level 0x12 (EAX). */ 40 #define KVM_X86_FEATURE_SGX1 KVM_X86_FEATURE(CPUID_12_EAX, 0) 41 #define KVM_X86_FEATURE_SGX2 KVM_X86_FEATURE(CPUID_12_EAX, 1) 42 #define KVM_X86_FEATURE_SGX_EDECCSSA KVM_X86_FEATURE(CPUID_12_EAX, 11) 43 44 /* Intel-defined sub-features, CPUID level 0x00000007:1 (EDX) */ 45 #define X86_FEATURE_AVX_VNNI_INT8 KVM_X86_FEATURE(CPUID_7_1_EDX, 4) 46 #define X86_FEATURE_AVX_NE_CONVERT KVM_X86_FEATURE(CPUID_7_1_EDX, 5) 47 #define X86_FEATURE_AMX_COMPLEX KVM_X86_FEATURE(CPUID_7_1_EDX, 8) 48 #define X86_FEATURE_PREFETCHITI KVM_X86_FEATURE(CPUID_7_1_EDX, 14) 49 50 /* Intel-defined sub-features, CPUID level 0x00000007:2 (EDX) */ 51 #define X86_FEATURE_INTEL_PSFD KVM_X86_FEATURE(CPUID_7_2_EDX, 0) 52 #define X86_FEATURE_IPRED_CTRL KVM_X86_FEATURE(CPUID_7_2_EDX, 1) 53 #define KVM_X86_FEATURE_RRSBA_CTRL KVM_X86_FEATURE(CPUID_7_2_EDX, 2) 54 #define X86_FEATURE_DDPD_U KVM_X86_FEATURE(CPUID_7_2_EDX, 3) 55 #define X86_FEATURE_BHI_CTRL KVM_X86_FEATURE(CPUID_7_2_EDX, 4) 56 #define X86_FEATURE_MCDT_NO KVM_X86_FEATURE(CPUID_7_2_EDX, 5) 57 58 /* CPUID level 0x80000007 (EDX). */ 59 #define KVM_X86_FEATURE_CONSTANT_TSC KVM_X86_FEATURE(CPUID_8000_0007_EDX, 8) 60 61 /* CPUID level 0x80000022 (EAX) */ 62 #define KVM_X86_FEATURE_PERFMON_V2 KVM_X86_FEATURE(CPUID_8000_0022_EAX, 0) 63 64 struct cpuid_reg { 65 u32 function; 66 u32 index; 67 int reg; 68 }; 69 70 static const struct cpuid_reg reverse_cpuid[] = { 71 [CPUID_1_EDX] = { 1, 0, CPUID_EDX}, 72 [CPUID_8000_0001_EDX] = {0x80000001, 0, CPUID_EDX}, 73 [CPUID_8086_0001_EDX] = {0x80860001, 0, CPUID_EDX}, 74 [CPUID_1_ECX] = { 1, 0, CPUID_ECX}, 75 [CPUID_C000_0001_EDX] = {0xc0000001, 0, CPUID_EDX}, 76 [CPUID_8000_0001_ECX] = {0x80000001, 0, CPUID_ECX}, 77 [CPUID_7_0_EBX] = { 7, 0, CPUID_EBX}, 78 [CPUID_D_1_EAX] = { 0xd, 1, CPUID_EAX}, 79 [CPUID_8000_0008_EBX] = {0x80000008, 0, CPUID_EBX}, 80 [CPUID_6_EAX] = { 6, 0, CPUID_EAX}, 81 [CPUID_8000_000A_EDX] = {0x8000000a, 0, CPUID_EDX}, 82 [CPUID_7_ECX] = { 7, 0, CPUID_ECX}, 83 [CPUID_8000_0007_EBX] = {0x80000007, 0, CPUID_EBX}, 84 [CPUID_7_EDX] = { 7, 0, CPUID_EDX}, 85 [CPUID_7_1_EAX] = { 7, 1, CPUID_EAX}, 86 [CPUID_12_EAX] = {0x00000012, 0, CPUID_EAX}, 87 [CPUID_8000_001F_EAX] = {0x8000001f, 0, CPUID_EAX}, 88 [CPUID_7_1_EDX] = { 7, 1, CPUID_EDX}, 89 [CPUID_8000_0007_EDX] = {0x80000007, 0, CPUID_EDX}, 90 [CPUID_8000_0021_EAX] = {0x80000021, 0, CPUID_EAX}, 91 [CPUID_8000_0022_EAX] = {0x80000022, 0, CPUID_EAX}, 92 [CPUID_7_2_EDX] = { 7, 2, CPUID_EDX}, 93 }; 94 95 /* 96 * Reverse CPUID and its derivatives can only be used for hardware-defined 97 * feature words, i.e. words whose bits directly correspond to a CPUID leaf. 98 * Retrieving a feature bit or masking guest CPUID from a Linux-defined word 99 * is nonsensical as the bit number/mask is an arbitrary software-defined value 100 * and can't be used by KVM to query/control guest capabilities. And obviously 101 * the leaf being queried must have an entry in the lookup table. 102 */ 103 static __always_inline void reverse_cpuid_check(unsigned int x86_leaf) 104 { 105 BUILD_BUG_ON(x86_leaf == CPUID_LNX_1); 106 BUILD_BUG_ON(x86_leaf == CPUID_LNX_2); 107 BUILD_BUG_ON(x86_leaf == CPUID_LNX_3); 108 BUILD_BUG_ON(x86_leaf == CPUID_LNX_4); 109 BUILD_BUG_ON(x86_leaf >= ARRAY_SIZE(reverse_cpuid)); 110 BUILD_BUG_ON(reverse_cpuid[x86_leaf].function == 0); 111 } 112 113 /* 114 * Translate feature bits that are scattered in the kernel's cpufeatures word 115 * into KVM feature words that align with hardware's definitions. 116 */ 117 static __always_inline u32 __feature_translate(int x86_feature) 118 { 119 #define KVM_X86_TRANSLATE_FEATURE(f) \ 120 case X86_FEATURE_##f: return KVM_X86_FEATURE_##f 121 122 switch (x86_feature) { 123 KVM_X86_TRANSLATE_FEATURE(SGX1); 124 KVM_X86_TRANSLATE_FEATURE(SGX2); 125 KVM_X86_TRANSLATE_FEATURE(SGX_EDECCSSA); 126 KVM_X86_TRANSLATE_FEATURE(CONSTANT_TSC); 127 KVM_X86_TRANSLATE_FEATURE(PERFMON_V2); 128 KVM_X86_TRANSLATE_FEATURE(RRSBA_CTRL); 129 default: 130 return x86_feature; 131 } 132 } 133 134 static __always_inline u32 __feature_leaf(int x86_feature) 135 { 136 return __feature_translate(x86_feature) / 32; 137 } 138 139 /* 140 * Retrieve the bit mask from an X86_FEATURE_* definition. Features contain 141 * the hardware defined bit number (stored in bits 4:0) and a software defined 142 * "word" (stored in bits 31:5). The word is used to index into arrays of 143 * bit masks that hold the per-cpu feature capabilities, e.g. this_cpu_has(). 144 */ 145 static __always_inline u32 __feature_bit(int x86_feature) 146 { 147 x86_feature = __feature_translate(x86_feature); 148 149 reverse_cpuid_check(x86_feature / 32); 150 return 1 << (x86_feature & 31); 151 } 152 153 #define feature_bit(name) __feature_bit(X86_FEATURE_##name) 154 155 static __always_inline struct cpuid_reg x86_feature_cpuid(unsigned int x86_feature) 156 { 157 unsigned int x86_leaf = __feature_leaf(x86_feature); 158 159 reverse_cpuid_check(x86_leaf); 160 return reverse_cpuid[x86_leaf]; 161 } 162 163 static __always_inline u32 *__cpuid_entry_get_reg(struct kvm_cpuid_entry2 *entry, 164 u32 reg) 165 { 166 switch (reg) { 167 case CPUID_EAX: 168 return &entry->eax; 169 case CPUID_EBX: 170 return &entry->ebx; 171 case CPUID_ECX: 172 return &entry->ecx; 173 case CPUID_EDX: 174 return &entry->edx; 175 default: 176 BUILD_BUG(); 177 return NULL; 178 } 179 } 180 181 static __always_inline u32 *cpuid_entry_get_reg(struct kvm_cpuid_entry2 *entry, 182 unsigned int x86_feature) 183 { 184 const struct cpuid_reg cpuid = x86_feature_cpuid(x86_feature); 185 186 return __cpuid_entry_get_reg(entry, cpuid.reg); 187 } 188 189 static __always_inline u32 cpuid_entry_get(struct kvm_cpuid_entry2 *entry, 190 unsigned int x86_feature) 191 { 192 u32 *reg = cpuid_entry_get_reg(entry, x86_feature); 193 194 return *reg & __feature_bit(x86_feature); 195 } 196 197 static __always_inline bool cpuid_entry_has(struct kvm_cpuid_entry2 *entry, 198 unsigned int x86_feature) 199 { 200 return cpuid_entry_get(entry, x86_feature); 201 } 202 203 static __always_inline void cpuid_entry_clear(struct kvm_cpuid_entry2 *entry, 204 unsigned int x86_feature) 205 { 206 u32 *reg = cpuid_entry_get_reg(entry, x86_feature); 207 208 *reg &= ~__feature_bit(x86_feature); 209 } 210 211 static __always_inline void cpuid_entry_set(struct kvm_cpuid_entry2 *entry, 212 unsigned int x86_feature) 213 { 214 u32 *reg = cpuid_entry_get_reg(entry, x86_feature); 215 216 *reg |= __feature_bit(x86_feature); 217 } 218 219 static __always_inline void cpuid_entry_change(struct kvm_cpuid_entry2 *entry, 220 unsigned int x86_feature, 221 bool set) 222 { 223 u32 *reg = cpuid_entry_get_reg(entry, x86_feature); 224 225 /* 226 * Open coded instead of using cpuid_entry_{clear,set}() to coerce the 227 * compiler into using CMOV instead of Jcc when possible. 228 */ 229 if (set) 230 *reg |= __feature_bit(x86_feature); 231 else 232 *reg &= ~__feature_bit(x86_feature); 233 } 234 235 #endif /* ARCH_X86_KVM_REVERSE_CPUID_H */ 236