Re: Possible x2apic breakage

From: Ingo Molnar
Date: Thu Jan 29 2009 - 11:16:08 EST



* Jack Steiner <steiner@xxxxxxx> wrote:

> Suresh -
>
> This popped up in Ingo's x86 tree yesterday. This appears to be breaking
> on our simulator running in x2apic mode. If I understand the code,
> this is a real breakage and not a problem in our simulator:
>
>
> arch/x86/include/asm/genapic.h
>
> static inline unsigned int read_apic_id(void)
> {
> unsigned int reg;
>
> reg = *(u32 *)(APIC_BASE + APIC_ID);
> return apic->get_apic_id(reg);
> }
>
>
> As expected, the failure occurs right after:
>
> Enabling x2apic
> Enabled x2apic and interrupt-remapping
>
> The next reference to apicid tries to read from mem instead of MSRs.

yes - Suresh sent a fix earlier today. Could you please check latest
tip/master (v2.6.29-rc3-1212-g69f3c6d or later), does it work fine in your
simulator?

And i'll also merge struct apic_ops into struct genapic - now that genapic
is unified there's no reason for the two to be separate.

Ingo
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