I think I see a bug in IsProcessorFeaturePresent related to supporting more than 64 features.
The code does “cmp ecx,0xC0” so seems to be written as if up to 192 features are now supported. If less than 0x40, it uses KUSER_SHARED_DATA::ProcessorFeatures as before.
But, the code for 0x40-0xBF …
about 1 month ago