Re: [PATCH] x86/smpboot: Make logical package management more robust

Borislav Petkov
2016-12-08T09:14:00Z

On Thu, Dec 08, 2016 at 10:04:25AM +0100, Thomas Gleixner wrote:
> The logical package management has several issues:
>
> - The APIC ids provided by ACPI are not required to be the same as the
> initial APIC id which can be retrieved by CPUID. The APIC ids provided
> by ACPI are those which are written by the BIOS into the APIC. The
> initial id is set by hardware and can not be changed. The hardware
> provided ids contain the real hardware package information.
>
> Especially AMD sets the effective APIC id different from the hardware id
> as they need to reserve space for the IOAPIC ids starting at id 0.
>
> As a consequence those machines trigger the currently active firmware
> bug printouts in dmesg, These are obviously wrong.
>
> - Virtual machines have their own interesting way of enumerating APICs and
> packages which are not reliably covered by the current implementation.
>
> The sizing of the mapping array has been tweaked to be generously large to
> handle systems which provide a wrong core count when HT is disabled so the
> whole magic which checks for space in the physical hotplug case is not
> needed anymore.
>
> Simplify the whole machinery and do the mapping when the CPU starts and the
> CPUID derived physical package information is available. This solves the
> observed problems on AMD machines and works for the virtualization issues
> as well.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Already

Tested-by: Borislav Petkov <bp@suse.de>

Thanks!

--
Regards/Gruss,
Boris.

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