RE: [PATCH v2 08/25] KVM: VMX: Initialize VMCS FRED fields

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+#ifdef CONFIG_X86_64

is this #ifdeffery neccesary?

Yes, otherwise build fails on 32 bit.

I assume kvm_cpu_cap_has(X86_FEATURE_FRED) is always false for !CONFIG_X86_64. Looks most of FRED changes in core kernel don't have such #ifdeffery.

Because it's not a compile time false, instead false from runtime.

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• /* Per-CPU FRED MSRs */
  

Please explain why these six MSRs are updated here and why only they are updated in this comment.

The explanation is kind of implicit "per-CPU", I will make it more explicit.

Thanks! Xin