diff options
| author | Sean Christopherson <sean.j.christopherson@intel.com> | 2020-03-02 15:56:41 -0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-03-16 17:58:23 +0100 |
| commit | 66a6950f99950c77e2898e48d668eca1dac10a1e (patch) | |
| tree | 94cb49d0d7310f8e702aa659ce086e5876be4e2f /arch/x86/kvm/cpuid.h | |
| parent | 9e6d01c2d9088efb8326997cafa8580295a49435 (diff) | |
KVM: x86: Introduce kvm_cpu_caps to replace runtime CPUID masking
Calculate the CPUID masks for KVM_GET_SUPPORTED_CPUID at load time using
what is effectively a KVM-adjusted copy of boot_cpu_data, or more
precisely, the x86_capability array in boot_cpu_data.
In terms of KVM support, the vast majority of CPUID feature bits are
constant, and *all* feature support is known at KVM load time. Rather
than apply boot_cpu_data, which is effectively read-only after init,
at runtime, copy it into a KVM-specific array and use *that* to mask
CPUID registers.
In additional to consolidating the masking, kvm_cpu_caps can be adjusted
by SVM/VMX at load time and thus eliminate all feature bit manipulation
in ->set_supported_cpuid().
Opportunistically clean up a few warts:
- Replace bare "unsigned" with "unsigned int" when a feature flag is
captured in a local variable, e.g. f_nx.
- Sort the CPUID masks by function, index and register (alphabetically
for registers, i.e. EBX comes before ECX/EDX).
- Remove the superfluous /* cpuid 7.0.ecx */ comments.
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
[Call kvm_set_cpu_caps from kvm_x86_ops->hardware_setup due to fixed
GBPAGES patch. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/cpuid.h')
| -rw-r--r-- | arch/x86/kvm/cpuid.h | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h index 407dc26c0633..13374f885c81 100644 --- a/arch/x86/kvm/cpuid.h +++ b/arch/x86/kvm/cpuid.h @@ -6,6 +6,9 @@ #include <asm/cpu.h> #include <asm/processor.h> +extern u32 kvm_cpu_caps[NCAPINTS] __read_mostly; +void kvm_set_cpu_caps(void); + int kvm_update_cpuid(struct kvm_vcpu *vcpu); struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu, u32 function, u32 index); @@ -172,7 +175,8 @@ static __always_inline void cpuid_entry_mask(struct kvm_cpuid_entry2 *entry, { u32 *reg = cpuid_entry_get_reg(entry, leaf * 32); - *reg &= boot_cpu_data.x86_capability[leaf]; + BUILD_BUG_ON(leaf >= ARRAY_SIZE(kvm_cpu_caps)); + *reg &= kvm_cpu_caps[leaf]; } static __always_inline u32 *guest_cpuid_get_register(struct kvm_vcpu *vcpu, @@ -262,4 +266,20 @@ static inline bool cpuid_fault_enabled(struct kvm_vcpu *vcpu) MSR_MISC_FEATURES_ENABLES_CPUID_FAULT; } +static __always_inline void kvm_cpu_cap_clear(unsigned int x86_feature) +{ + unsigned int x86_leaf = x86_feature / 32; + + reverse_cpuid_check(x86_leaf); + kvm_cpu_caps[x86_leaf] &= ~__feature_bit(x86_feature); +} + +static __always_inline void kvm_cpu_cap_set(unsigned int x86_feature) +{ + unsigned int x86_leaf = x86_feature / 32; + + reverse_cpuid_check(x86_leaf); + kvm_cpu_caps[x86_leaf] |= __feature_bit(x86_feature); +} + #endif |