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186 lines
5.5 KiB
186 lines
5.5 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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#ifndef ARCH_X86_KVM_REVERSE_CPUID_H |
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#define ARCH_X86_KVM_REVERSE_CPUID_H |
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#include <uapi/asm/kvm.h> |
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#include <asm/cpufeature.h> |
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#include <asm/cpufeatures.h> |
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/* |
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* Hardware-defined CPUID leafs that are scattered in the kernel, but need to |
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* be directly used by KVM. Note, these word values conflict with the kernel's |
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* "bug" caps, but KVM doesn't use those. |
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*/ |
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enum kvm_only_cpuid_leafs { |
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CPUID_12_EAX = NCAPINTS, |
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NR_KVM_CPU_CAPS, |
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NKVMCAPINTS = NR_KVM_CPU_CAPS - NCAPINTS, |
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}; |
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#define KVM_X86_FEATURE(w, f) ((w)*32 + (f)) |
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/* Intel-defined SGX sub-features, CPUID level 0x12 (EAX). */ |
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#define KVM_X86_FEATURE_SGX1 KVM_X86_FEATURE(CPUID_12_EAX, 0) |
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#define KVM_X86_FEATURE_SGX2 KVM_X86_FEATURE(CPUID_12_EAX, 1) |
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struct cpuid_reg { |
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u32 function; |
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u32 index; |
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int reg; |
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}; |
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static const struct cpuid_reg reverse_cpuid[] = { |
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[CPUID_1_EDX] = { 1, 0, CPUID_EDX}, |
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[CPUID_8000_0001_EDX] = {0x80000001, 0, CPUID_EDX}, |
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[CPUID_8086_0001_EDX] = {0x80860001, 0, CPUID_EDX}, |
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[CPUID_1_ECX] = { 1, 0, CPUID_ECX}, |
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[CPUID_C000_0001_EDX] = {0xc0000001, 0, CPUID_EDX}, |
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[CPUID_8000_0001_ECX] = {0x80000001, 0, CPUID_ECX}, |
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[CPUID_7_0_EBX] = { 7, 0, CPUID_EBX}, |
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[CPUID_D_1_EAX] = { 0xd, 1, CPUID_EAX}, |
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[CPUID_8000_0008_EBX] = {0x80000008, 0, CPUID_EBX}, |
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[CPUID_6_EAX] = { 6, 0, CPUID_EAX}, |
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[CPUID_8000_000A_EDX] = {0x8000000a, 0, CPUID_EDX}, |
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[CPUID_7_ECX] = { 7, 0, CPUID_ECX}, |
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[CPUID_8000_0007_EBX] = {0x80000007, 0, CPUID_EBX}, |
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[CPUID_7_EDX] = { 7, 0, CPUID_EDX}, |
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[CPUID_7_1_EAX] = { 7, 1, CPUID_EAX}, |
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[CPUID_12_EAX] = {0x00000012, 0, CPUID_EAX}, |
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[CPUID_8000_001F_EAX] = {0x8000001f, 0, CPUID_EAX}, |
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}; |
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/* |
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* Reverse CPUID and its derivatives can only be used for hardware-defined |
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* feature words, i.e. words whose bits directly correspond to a CPUID leaf. |
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* Retrieving a feature bit or masking guest CPUID from a Linux-defined word |
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* is nonsensical as the bit number/mask is an arbitrary software-defined value |
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* and can't be used by KVM to query/control guest capabilities. And obviously |
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* the leaf being queried must have an entry in the lookup table. |
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*/ |
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static __always_inline void reverse_cpuid_check(unsigned int x86_leaf) |
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{ |
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BUILD_BUG_ON(x86_leaf == CPUID_LNX_1); |
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BUILD_BUG_ON(x86_leaf == CPUID_LNX_2); |
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BUILD_BUG_ON(x86_leaf == CPUID_LNX_3); |
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BUILD_BUG_ON(x86_leaf == CPUID_LNX_4); |
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BUILD_BUG_ON(x86_leaf >= ARRAY_SIZE(reverse_cpuid)); |
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BUILD_BUG_ON(reverse_cpuid[x86_leaf].function == 0); |
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} |
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/* |
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* Translate feature bits that are scattered in the kernel's cpufeatures word |
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* into KVM feature words that align with hardware's definitions. |
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*/ |
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static __always_inline u32 __feature_translate(int x86_feature) |
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{ |
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if (x86_feature == X86_FEATURE_SGX1) |
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return KVM_X86_FEATURE_SGX1; |
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else if (x86_feature == X86_FEATURE_SGX2) |
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return KVM_X86_FEATURE_SGX2; |
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return x86_feature; |
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} |
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static __always_inline u32 __feature_leaf(int x86_feature) |
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{ |
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return __feature_translate(x86_feature) / 32; |
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} |
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/* |
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* Retrieve the bit mask from an X86_FEATURE_* definition. Features contain |
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* the hardware defined bit number (stored in bits 4:0) and a software defined |
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* "word" (stored in bits 31:5). The word is used to index into arrays of |
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* bit masks that hold the per-cpu feature capabilities, e.g. this_cpu_has(). |
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*/ |
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static __always_inline u32 __feature_bit(int x86_feature) |
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{ |
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x86_feature = __feature_translate(x86_feature); |
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reverse_cpuid_check(x86_feature / 32); |
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return 1 << (x86_feature & 31); |
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} |
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#define feature_bit(name) __feature_bit(X86_FEATURE_##name) |
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static __always_inline struct cpuid_reg x86_feature_cpuid(unsigned int x86_feature) |
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{ |
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unsigned int x86_leaf = __feature_leaf(x86_feature); |
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reverse_cpuid_check(x86_leaf); |
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return reverse_cpuid[x86_leaf]; |
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} |
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static __always_inline u32 *__cpuid_entry_get_reg(struct kvm_cpuid_entry2 *entry, |
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u32 reg) |
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{ |
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switch (reg) { |
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case CPUID_EAX: |
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return &entry->eax; |
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case CPUID_EBX: |
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return &entry->ebx; |
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case CPUID_ECX: |
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return &entry->ecx; |
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case CPUID_EDX: |
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return &entry->edx; |
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default: |
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BUILD_BUG(); |
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return NULL; |
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} |
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} |
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static __always_inline u32 *cpuid_entry_get_reg(struct kvm_cpuid_entry2 *entry, |
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unsigned int x86_feature) |
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{ |
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const struct cpuid_reg cpuid = x86_feature_cpuid(x86_feature); |
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return __cpuid_entry_get_reg(entry, cpuid.reg); |
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} |
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static __always_inline u32 cpuid_entry_get(struct kvm_cpuid_entry2 *entry, |
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unsigned int x86_feature) |
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{ |
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u32 *reg = cpuid_entry_get_reg(entry, x86_feature); |
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return *reg & __feature_bit(x86_feature); |
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} |
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static __always_inline bool cpuid_entry_has(struct kvm_cpuid_entry2 *entry, |
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unsigned int x86_feature) |
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{ |
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return cpuid_entry_get(entry, x86_feature); |
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} |
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static __always_inline void cpuid_entry_clear(struct kvm_cpuid_entry2 *entry, |
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unsigned int x86_feature) |
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{ |
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u32 *reg = cpuid_entry_get_reg(entry, x86_feature); |
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*reg &= ~__feature_bit(x86_feature); |
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} |
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static __always_inline void cpuid_entry_set(struct kvm_cpuid_entry2 *entry, |
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unsigned int x86_feature) |
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{ |
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u32 *reg = cpuid_entry_get_reg(entry, x86_feature); |
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*reg |= __feature_bit(x86_feature); |
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} |
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static __always_inline void cpuid_entry_change(struct kvm_cpuid_entry2 *entry, |
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unsigned int x86_feature, |
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bool set) |
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{ |
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u32 *reg = cpuid_entry_get_reg(entry, x86_feature); |
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/* |
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* Open coded instead of using cpuid_entry_{clear,set}() to coerce the |
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* compiler into using CMOV instead of Jcc when possible. |
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*/ |
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if (set) |
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*reg |= __feature_bit(x86_feature); |
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else |
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*reg &= ~__feature_bit(x86_feature); |
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} |
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#endif /* ARCH_X86_KVM_REVERSE_CPUID_H */
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