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 | NR_KVM_CPU_CAPS, |
20 | |
21 | NKVMCAPINTS = NR_KVM_CPU_CAPS - NCAPINTS, |
22 | }; |
23 | |
24 | /* |
25 | * Define a KVM-only feature flag. |
26 | * |
27 | * For features that are scattered by cpufeatures.h, __feature_translate() also |
28 | * needs to be updated to translate the kernel-defined feature into the |
29 | * KVM-defined feature. |
30 | * |
31 | * For features that are 100% KVM-only, i.e. not defined by cpufeatures.h, |
32 | * forego the intermediate KVM_X86_FEATURE and directly define X86_FEATURE_* so |
33 | * that X86_FEATURE_* can be used in KVM. No __feature_translate() handling is |
34 | * needed in this case. |
35 | */ |
36 | #define KVM_X86_FEATURE(w, f) ((w)*32 + (f)) |
37 | |
38 | /* Intel-defined SGX sub-features, CPUID level 0x12 (EAX). */ |
39 | #define KVM_X86_FEATURE_SGX1 KVM_X86_FEATURE(CPUID_12_EAX, 0) |
40 | #define KVM_X86_FEATURE_SGX2 KVM_X86_FEATURE(CPUID_12_EAX, 1) |
41 | #define KVM_X86_FEATURE_SGX_EDECCSSA KVM_X86_FEATURE(CPUID_12_EAX, 11) |
42 | |
43 | /* Intel-defined sub-features, CPUID level 0x00000007:1 (EDX) */ |
44 | #define X86_FEATURE_AVX_VNNI_INT8 KVM_X86_FEATURE(CPUID_7_1_EDX, 4) |
45 | #define X86_FEATURE_AVX_NE_CONVERT KVM_X86_FEATURE(CPUID_7_1_EDX, 5) |
46 | #define X86_FEATURE_AMX_COMPLEX KVM_X86_FEATURE(CPUID_7_1_EDX, 8) |
47 | #define X86_FEATURE_PREFETCHITI KVM_X86_FEATURE(CPUID_7_1_EDX, 14) |
48 | |
49 | /* CPUID level 0x80000007 (EDX). */ |
50 | #define KVM_X86_FEATURE_CONSTANT_TSC KVM_X86_FEATURE(CPUID_8000_0007_EDX, 8) |
51 | |
52 | /* CPUID level 0x80000022 (EAX) */ |
53 | #define KVM_X86_FEATURE_PERFMON_V2 KVM_X86_FEATURE(CPUID_8000_0022_EAX, 0) |
54 | |
55 | struct cpuid_reg { |
56 | u32 function; |
57 | u32 index; |
58 | int reg; |
59 | }; |
60 | |
61 | static const struct cpuid_reg reverse_cpuid[] = { |
62 | [CPUID_1_EDX] = { 1, 0, CPUID_EDX}, |
63 | [CPUID_8000_0001_EDX] = {.function: 0x80000001, .index: 0, .reg: CPUID_EDX}, |
64 | [CPUID_8086_0001_EDX] = {.function: 0x80860001, .index: 0, .reg: CPUID_EDX}, |
65 | [CPUID_1_ECX] = { .function: 1, .index: 0, .reg: CPUID_ECX}, |
66 | [CPUID_C000_0001_EDX] = {.function: 0xc0000001, .index: 0, .reg: CPUID_EDX}, |
67 | [CPUID_8000_0001_ECX] = {.function: 0x80000001, .index: 0, .reg: CPUID_ECX}, |
68 | [CPUID_7_0_EBX] = { .function: 7, .index: 0, .reg: CPUID_EBX}, |
69 | [CPUID_D_1_EAX] = { .function: 0xd, .index: 1, .reg: CPUID_EAX}, |
70 | [CPUID_8000_0008_EBX] = {.function: 0x80000008, .index: 0, .reg: CPUID_EBX}, |
71 | [CPUID_6_EAX] = { .function: 6, .index: 0, .reg: CPUID_EAX}, |
72 | [CPUID_8000_000A_EDX] = {.function: 0x8000000a, .index: 0, .reg: CPUID_EDX}, |
73 | [CPUID_7_ECX] = { .function: 7, .index: 0, .reg: CPUID_ECX}, |
74 | [CPUID_8000_0007_EBX] = {.function: 0x80000007, .index: 0, .reg: CPUID_EBX}, |
75 | [CPUID_7_EDX] = { .function: 7, .index: 0, .reg: CPUID_EDX}, |
76 | [CPUID_7_1_EAX] = { .function: 7, .index: 1, .reg: CPUID_EAX}, |
77 | [CPUID_12_EAX] = {.function: 0x00000012, .index: 0, .reg: CPUID_EAX}, |
78 | [CPUID_8000_001F_EAX] = {.function: 0x8000001f, .index: 0, .reg: CPUID_EAX}, |
79 | [CPUID_7_1_EDX] = { .function: 7, .index: 1, .reg: CPUID_EDX}, |
80 | [CPUID_8000_0007_EDX] = {.function: 0x80000007, .index: 0, .reg: CPUID_EDX}, |
81 | [CPUID_8000_0021_EAX] = {.function: 0x80000021, .index: 0, .reg: CPUID_EAX}, |
82 | [CPUID_8000_0022_EAX] = {.function: 0x80000022, .index: 0, .reg: CPUID_EAX}, |
83 | }; |
84 | |
85 | /* |
86 | * Reverse CPUID and its derivatives can only be used for hardware-defined |
87 | * feature words, i.e. words whose bits directly correspond to a CPUID leaf. |
88 | * Retrieving a feature bit or masking guest CPUID from a Linux-defined word |
89 | * is nonsensical as the bit number/mask is an arbitrary software-defined value |
90 | * and can't be used by KVM to query/control guest capabilities. And obviously |
91 | * the leaf being queried must have an entry in the lookup table. |
92 | */ |
93 | static __always_inline void reverse_cpuid_check(unsigned int x86_leaf) |
94 | { |
95 | BUILD_BUG_ON(x86_leaf == CPUID_LNX_1); |
96 | BUILD_BUG_ON(x86_leaf == CPUID_LNX_2); |
97 | BUILD_BUG_ON(x86_leaf == CPUID_LNX_3); |
98 | BUILD_BUG_ON(x86_leaf == CPUID_LNX_4); |
99 | BUILD_BUG_ON(x86_leaf >= ARRAY_SIZE(reverse_cpuid)); |
100 | BUILD_BUG_ON(reverse_cpuid[x86_leaf].function == 0); |
101 | } |
102 | |
103 | /* |
104 | * Translate feature bits that are scattered in the kernel's cpufeatures word |
105 | * into KVM feature words that align with hardware's definitions. |
106 | */ |
107 | static __always_inline u32 __feature_translate(int x86_feature) |
108 | { |
109 | if (x86_feature == X86_FEATURE_SGX1) |
110 | return KVM_X86_FEATURE_SGX1; |
111 | else if (x86_feature == X86_FEATURE_SGX2) |
112 | return KVM_X86_FEATURE_SGX2; |
113 | else if (x86_feature == X86_FEATURE_SGX_EDECCSSA) |
114 | return KVM_X86_FEATURE_SGX_EDECCSSA; |
115 | else if (x86_feature == X86_FEATURE_CONSTANT_TSC) |
116 | return KVM_X86_FEATURE_CONSTANT_TSC; |
117 | else if (x86_feature == X86_FEATURE_PERFMON_V2) |
118 | return KVM_X86_FEATURE_PERFMON_V2; |
119 | |
120 | return x86_feature; |
121 | } |
122 | |
123 | static __always_inline u32 __feature_leaf(int x86_feature) |
124 | { |
125 | return __feature_translate(x86_feature) / 32; |
126 | } |
127 | |
128 | /* |
129 | * Retrieve the bit mask from an X86_FEATURE_* definition. Features contain |
130 | * the hardware defined bit number (stored in bits 4:0) and a software defined |
131 | * "word" (stored in bits 31:5). The word is used to index into arrays of |
132 | * bit masks that hold the per-cpu feature capabilities, e.g. this_cpu_has(). |
133 | */ |
134 | static __always_inline u32 __feature_bit(int x86_feature) |
135 | { |
136 | x86_feature = __feature_translate(x86_feature); |
137 | |
138 | reverse_cpuid_check(x86_leaf: x86_feature / 32); |
139 | return 1 << (x86_feature & 31); |
140 | } |
141 | |
142 | #define feature_bit(name) __feature_bit(X86_FEATURE_##name) |
143 | |
144 | static __always_inline struct cpuid_reg x86_feature_cpuid(unsigned int x86_feature) |
145 | { |
146 | unsigned int x86_leaf = __feature_leaf(x86_feature); |
147 | |
148 | reverse_cpuid_check(x86_leaf); |
149 | return reverse_cpuid[x86_leaf]; |
150 | } |
151 | |
152 | static __always_inline u32 *__cpuid_entry_get_reg(struct kvm_cpuid_entry2 *entry, |
153 | u32 reg) |
154 | { |
155 | switch (reg) { |
156 | case CPUID_EAX: |
157 | return &entry->eax; |
158 | case CPUID_EBX: |
159 | return &entry->ebx; |
160 | case CPUID_ECX: |
161 | return &entry->ecx; |
162 | case CPUID_EDX: |
163 | return &entry->edx; |
164 | default: |
165 | BUILD_BUG(); |
166 | return NULL; |
167 | } |
168 | } |
169 | |
170 | static __always_inline u32 *cpuid_entry_get_reg(struct kvm_cpuid_entry2 *entry, |
171 | unsigned int x86_feature) |
172 | { |
173 | const struct cpuid_reg cpuid = x86_feature_cpuid(x86_feature); |
174 | |
175 | return __cpuid_entry_get_reg(entry, reg: cpuid.reg); |
176 | } |
177 | |
178 | static __always_inline u32 cpuid_entry_get(struct kvm_cpuid_entry2 *entry, |
179 | unsigned int x86_feature) |
180 | { |
181 | u32 *reg = cpuid_entry_get_reg(entry, x86_feature); |
182 | |
183 | return *reg & __feature_bit(x86_feature); |
184 | } |
185 | |
186 | static __always_inline bool cpuid_entry_has(struct kvm_cpuid_entry2 *entry, |
187 | unsigned int x86_feature) |
188 | { |
189 | return cpuid_entry_get(entry, x86_feature); |
190 | } |
191 | |
192 | static __always_inline void cpuid_entry_clear(struct kvm_cpuid_entry2 *entry, |
193 | unsigned int x86_feature) |
194 | { |
195 | u32 *reg = cpuid_entry_get_reg(entry, x86_feature); |
196 | |
197 | *reg &= ~__feature_bit(x86_feature); |
198 | } |
199 | |
200 | static __always_inline void cpuid_entry_set(struct kvm_cpuid_entry2 *entry, |
201 | unsigned int x86_feature) |
202 | { |
203 | u32 *reg = cpuid_entry_get_reg(entry, x86_feature); |
204 | |
205 | *reg |= __feature_bit(x86_feature); |
206 | } |
207 | |
208 | static __always_inline void cpuid_entry_change(struct kvm_cpuid_entry2 *entry, |
209 | unsigned int x86_feature, |
210 | bool set) |
211 | { |
212 | u32 *reg = cpuid_entry_get_reg(entry, x86_feature); |
213 | |
214 | /* |
215 | * Open coded instead of using cpuid_entry_{clear,set}() to coerce the |
216 | * compiler into using CMOV instead of Jcc when possible. |
217 | */ |
218 | if (set) |
219 | *reg |= __feature_bit(x86_feature); |
220 | else |
221 | *reg &= ~__feature_bit(x86_feature); |
222 | } |
223 | |
224 | #endif /* ARCH_X86_KVM_REVERSE_CPUID_H */ |
225 | |