Re: [PATCH 04/12] x86/mm: get INVLPGB count max from CPUID

[Rik van Riel]

On Fri, 2025-01-10 at 12:44 -0600, Tom Lendacky wrote:
> On 12/30/24 11:53, Rik van Riel wrote:
> > 
> > +++ b/arch/x86/kernel/cpu/amd.c
> > @@ -1135,6 +1135,14 @@ static void cpu_detect_tlb_amd(struct
> > cpuinfo_x86 *c)
> >  		tlb_lli_2m[ENTRIES] = eax & mask;
> >  
> >  	tlb_lli_4m[ENTRIES] = tlb_lli_2m[ENTRIES] >> 1;
> > +
> > +	if (c->extended_cpuid_level < 0x80000008)
> > +		return;
> 
> Can this just be based on cpu_feature_enabled(X86_FEATURE_TLBI), e.g:
> 
> 	if (cpu_feature_enabled(X86_FEATURE_TLBI))
> 		invlpgb_count_max = (cpuid_edx(0x80000008) & 0xffff)
> + 1
> 
I don't see X86_FEATURE_TLBI defined in the tip
tree. Which CPUID bit does that need to be?

> Then you can squash this and the previous patch.

Heh, I already squashed the previous commit into
what is patch 6 in this series, as requested by
Borislav :)

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