KVM: x86: Introduce kvm_cpu_caps to replace runtime CPUID masking

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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>

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This commit is contained in:

Sean Christopherson 2020-03-02 15:56:41 -08:00 • committed by Paolo Bonzini

parent 9e6d01c2d9

commit 66a6950f99

4 changed files with 151 additions and 108 deletions

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233

arch/x86/kvm/cpuid.c

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22

arch/x86/kvm/cpuid.h

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2

arch/x86/kvm/svm.c

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2

arch/x86/kvm/vmx/vmx.c

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