Re: [PATCH v2] x86/acpi/boot: Do not register processors that cannot be onlined for x2apic

Borislav Petkov
2023-01-05T22:22:16Z

On Thu, Jan 05, 2023 at 06:09:59PM +0100, Rafael J. Wysocki wrote:
> On Thu, Jan 5, 2023 at 5:11 AM Kishon Vijay Abraham I <kvijayab@amd.com> wrote:
> >
> > Section 5.2.12.12 Processor Local x2APIC Structure in the ACPI v6.5
> > spec mandates that both "enabled" and "online capable" Local APIC Flags
> > should be used to determine if the processor is usable or not.
> >
> > However, Linux doesn't use the "online capable" flag for x2APIC to
> > determine if the processor is usable. As a result, cpu_possible_mask has
> > incorrect value and results in more memory getting allocated for per_cpu
> > variables than it is going to be used.
> >
> > Make sure Linux parses both "enabled" and "online capable" flags for
> > x2APIC to correctly determine if the processor is usable.
> >
> > Fixes: aa06e20f1be6 ("x86/ACPI: Don't add CPUs that are not online capable")
> > Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
> > Reported-by: Leo Duran <leo.duran@amd.com>
> > Signed-off-by: Kishon Vijay Abraham I <kvijayab@amd.com>
>
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Are you saying, I should take it through tip?

--
Regards/Gruss,
Boris.