Re: Dont record local apic ids when they are disabled in MADT

[Andi Kleen <ak@suse.de>]

On Thursday 26 January 2006 15:10, Ashok Raj wrote:
> On Thu, Jan 26, 2006 at 02:55:11PM +0100, Andi Kleen wrote:
> > On Thursday 26 January 2006 14:48, Ashok Raj wrote:
> > > Hi Andrew,
> > > 
> > > We had added additional_cpus=xx for x86_64, but apparently there were some
> > > BIOSs that had duplicate apic ids when they were reported disabled.
> > > 
> > > It seems fair not to record them, this was causing some bad behaviour due to
> > > the duplicate apic id. More details in the bugzilla recorded in the log.
> > 
> > This means CPU hotplug will require additional non existing code again - or who
> > will set up the APIC IDs etc. for the new CPUs then?
> 
> 
> The ACPI hotplug code already would refresh this apic id when the notify
> for CPU hotplug is processed. 

How? All the code who could do this is __init.

> (although i would say we tested this only on ia64 so far, the code is 
> generic to x86_64 as well, but i havent gone around testing physical hotplug
> via emulation patches we have internally)

I doubt it will work on x86-64.

And you're breaking the CPU hotplug spec in Documentation/x86-64/cpu-hotplug-spec.
I think the BIOS bugs need to be workarounded without breaking that.


-Andi