Re: [PATCH v6 00/90] x86: Introduce a centralized CPUID data model

[Borislav Petkov]

On Mon, Apr 27, 2026 at 08:45:23PM +0200, Ahmed S. Darwish wrote:
> * Keep the current synthetic CPUID(0x4c780001) and CPUID(0x4c780002)
>   bitfield listings, with their hardware-backed scattered bits, as is.
>   Mark them as "v1" instead of setting them in stone.

Except that they're already cast in stone:

https://gitlab.com/x86-cpuid.org/x86-cpuid-db/-/blob/tip/db/xml/leaf_4c780001.xml

and that 02 one.

I don't want any of that to be in any database - this is Linux-internal only
and needs to go from there and nothing should depend on it.

So, instead of taking this and then converting stuff ontop, the proper thing
to do would be:

- rip out the linux-specific leafs from the cpuid db
- keep both facilities in the kernel for querying and convert the hardware
  leafs to the new method but use the old method for querying the synthetic
  leafs. I'm sure we can multiplex between the two in cpu_feature_enabled()

- then start converting the synthetic ones to hidden, Linux-specific ones

Ok?

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette