Re: [PATCH 8/8] x86_64: Support for new UV apic

Yinghai Lu
2008-03-31T02:23:26Z

On Sun, Mar 30, 2008 at 7:12 PM, Jack Steiner <steiner@sgi.com> wrote:
> > > Did you test it on non UV_X2APIC box?
> >
> > anyway the read_apic_id is totally wrong, even for your UV_X2APIC box.
> > because id=apic_read(APIC_ID) will have apic_id at bits [31,24], and
> > id |= __get_cpu_var(x2apic_extra_bits) is assuming that is on bits [5,0]
> >
> > so you even didn't test in your UV_X2APIC box!
> >
>
> It works fine on UV_X2APIX boxes because the double shift does
> not occur. However, support for UV_X2APIC is dependent on
> x2apic code that is not yet in the tree. Once the APIC
> is switched into x2apic mode, the apicid is located in the LOW
> bits of the apicid register, not the HIGH bits.

oh, so that will need have new version GET_APIC_ID too.

YH