Re: [PATCH] x86/cpu/centaur: Disable X86_FEATURE_FSGSBASE on Zhaoxin C4600

[Dave Hansen]

On 2/28/26 09:37, Yao Zi wrote:
> Let's disable the feature on this problematic CPU and warn the user
> about the quirk. x86_model_id is used to match the platform to avoid
> unexpectedly breaking other CentaurHauls cores with conflicting
> family/model ID.

Wait a sec. There are lots of different microarchitectures with the same
family/model and no other way to identify them but the model id string?

We've used string in a handful of places, but it's an absolute last
resort. Are you *sure* there's no stepping or anything?

I kinda think we should keep this like all the other vendors and keep it
to model/family/stepping. If the vendor has grouped too many
non-vulnerable CPUs under that, then ... this is going to be a good
learning to bring back to the CPU design team.

If you're changing the CPU in a way that it's possible to regress
things, you *need* to bump the model or stepping. Period. If you don't,
the baby might get thrown out with the bathwater.

Please resend this with a normal x86_match_cpu() and x86_cpu_id[] array.