RE: [PATCH v2 11/25] KVM: x86: Add kvm_is_fred_enabled()

...

+/*

• • It's enough to check just CR4.FRED (X86_CR4_FRED) to tell if
• • a vCPU is running with FRED enabled, because:
• • 1. CR4.FRED can be set to 1 only _after_ IA32_EFER.LMA = 1.
• • 2. To leave IA-32e mode, CR4.FRED must be cleared first.
• • More details at FRED Spec 6.0 Section 4.2 Enabling in CR4.
• */

I think we can give more context here, e.g.,

Although FRED architecture applies to 64-bit mode only, there is no need to check if the CPU is in 64-bit mode (i.e., IA32_EFER.LMA and CS.L) to tell if FRED is enabled because CR4.FRED=1 implies the CPU is in 64-bit mode.

What is "more context" here?

Specifically,