On Sun, Aug 24 2025 at 15:38, Thomas Gleixner wrote:
>> - if (!has_topoext) {
>> + if (!cpu_feature_enabled(X86_FEATURE_XTOPOLOGY)) {
>> /*
>> * Prefer initial_apicid parsed from XTOPOLOGY leaf
>> * 0x8000026 or 0xb if available. Otherwise prefer the
>
> That's patently wrong.
>
> The leaves might be "available", but are not guaranteed to be valid. So
> FEATURE_XTOPOLOGY gives you the wrong answer.
>
> The has_topoext logic is there for a reason.
Hrm. I have to correct myself. It's set by the 0xb... parsing when that
finds a valid leaf. My memory tricked me on that.
So yes, it can be used for that, but that's a cleanup. The simple fix
should be applied first as that's trivial to backport.
