On Wed, May 31, 2023 at 08:18:34PM +0000, Sean Christopherson wrote: > Assert that the to-be-checked bit passed to cpu_feature_enabled() is a > compile-time constant instead of applying the DISABLED_MASK_BIT_SET() > logic if and only if the bit is a constant. Conditioning the check on > the bit being constant instead of requiring the bit to be constant could > result in compiler specific kernel behavior, e.g. running on hardware that > supports a disabled feature would return %false if the compiler resolved > the bit to a constant, but %true if not. Uff, more mirroring CPUID inconsistencies. So *actually*, we should clear all those build-time disabled bits from x86_capability so that this doesn't happen. > All current usage of cpu_feature_enabled() specifies a hardcoded > X86_FEATURE_* flag, so this *should* be a glorified nop. Also, pls add here the exact example which prompted this as I'm sure we will forget why this was done. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette