Re: [patch 00/26] x64, x2apic/intr-remap: Interrupt-remapping and x2apic support

[ebiederm@xmission.com (Eric W. Biederman)]

"Yinghai Lu" <yhlu.kernel@gmail.com> writes:

> 1. wonder if x2apic can be use with uniprocessor.
>
> in APIC_init_uniprocessor, it will try to enable x2apic, but later
>
> apic_write(APIC_ID, SET_APIC_ID(boot_cpu_physical_apicid));
>
> but SET_APIC_ID is still for xapic version. so need to GET_APIC_ID,
> SET_APIC_ID for different
> genapic like 32bit.
>
> 2 check_x2apic is called in setup_arch, but it only set apic_ops,
> and genapic still not changed, aka apic_flat...
> wonder if you need to call setup_apic_routing to set genapic.
>
> otherwise read_apic_id could have use the one from apic_flat....need
> to shift......
>
> 3.or move read_apic_id to apic_ops intead...together with GET_APIC_ID too.
> but 32bit version seems like to put GET_APIC_ID with genapic...
>
> which one is better? 2 or 3

Z finish untangle SMP support from apic initialization and move the apic
initialization up into init_IRQ.

That is better but is likely the wrong short term approach.

Eric