Re: [PATCH v6 09/90] x86/cpuid: Introduce a centralized CPUID parser

[Ahmed S. Darwish]

On Wed, 15 Apr 2026, Maciej Wieczor-Retman wrote:
>
> Also should cpuid_parser.c/.h be attached to some subsystem in
> MAINTAINERS? Not sure if it should or shouldn't but I noticed you added
> leaf_types.h before and was curious if not adding new files is
> intentional here.
>

IMHO, it should be maintained just like any other code within the x86 tree.

leaf_types.h is added to MAINTAINERS x86 CPUID database entry at the
previous patch so that I can catch anyone modifying it outside of
x86-cpuid-db.

>
> >
> ...
> >diff --git a/arch/x86/kernel/cpu/cpuid_parser.c b/arch/x86/kernel/cpu/cpuid_parser.c
> >new file mode 100644
> >index 000000000000..898b0c441431
> >--- /dev/null
> >+++ b/arch/x86/kernel/cpu/cpuid_parser.c
> ...
> >+static unsigned int cpuid_range_max_leaf(const struct cpuid_table *t, unsigned int range)
> >+{
> >+	const struct leaf_0x0_0 *l0 = __cpuid_table_subleaf(t, 0x0, 0);
> >+
> >+	switch (range) {
> >+	case CPUID_BASE_START:	return l0  ?  l0->max_std_leaf : 0;
> >+	default:		return 0;
> >+	}
> >+}
>
> Trailing statements should go on the next line, right?
>

By the end of this patch queue, this aligns well as a table:

	switch (range) {
	case CPUID_BASE_START:	return l0  ?  l0->max_std_leaf  : 0;
	case CPUID_EXT_START:	return el0 ? el0->max_ext_leaf  : 0;
	case CPUID_TMX_START:	return tl0 ? tl0->max_tra_leaf  : 0;
	case CPUID_CTR_START:	return cl0 ? cl0->max_cntr_leaf : 0;
	case CPUID_LNX_START:	return CPUID_LNX_END;
	default:		return 0;
	}

Thanks,
Ahmed