x86/kvm: use Enlightened VMCS when running on Hyper-V
Enlightened VMCS is just a structure in memory, the main benefit besides avoiding somewhat slower VMREAD/VMWRITE is using clean field mask: we tell the underlying hypervisor which fields were modified since VMEXIT so there's no need to inspect them all. Tight CPUID loop test shows significant speedup: Before: 18890 cycles After: 8304 cycles Static key is being used to avoid performance penalty for non-Hyper-V deployments. Signed-off-by:Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by:
Radim Krčmář <rkrcmar@redhat.com> Signed-off-by:
Radim Krčmář <rkrcmar@redhat.com>
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5431390b
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