Re: [PATCH v2 13/17] x86/pat: Replace Intel x86_model checks with VFM ones

[Sohil Mehta]

On 2/11/2025 1:09 PM, Dave Hansen wrote:
> On 2/11/25 11:44, Sohil Mehta wrote:
>> +	if (c->x86_vendor == X86_VENDOR_INTEL &&
>> +	    ((c->x86_vfm >= INTEL_PENTIUM_PRO && c->x86_vfm <= INTEL_PENTIUM_M_DOTHAN) ||
>> +	    (c->x86_vfm >= INTEL_P4_WILLAMETTE && c->x86_vfm <= INTEL_P4_CEDARMILL))) {
> 
> Since these are both closed checks and not open-ended, is the
> 
> 	if (c->x86_vendor == X86_VENDOR_INTEL &&
> 
> bit needed or superfluous?
> 

You are right, since it is close ended on both sides we should be able
to remove the X86_VENDOR_INTEL.

I was thinking if we should leave it there to avoid confusion. But,
INTEL_* in the VFM string is a good enough hint that the checks are
Intel specific. Also, it's not like this check is going to be modified
frequently.

> Also, super nit, can you vertically align the two range checks, please?
> 
> 	    ((c->x86_vfm >= INTEL_PENTIUM_PRO   && c->x86_vfm <=
> INTEL_PENTIUM_M_DOTHAN) ||
> 	     (c->x86_vfm >= INTEL_P4_WILLAMETTE && c->x86_vfm <=
> INTEL_P4_CEDARMILL))) {
> 
>