Re: [tip: x86/urgent] x86/apic: Don't access the APIC when disabling X2APIC

* tip-bot2 for Thomas Gleixner tip-bot2@linutronix.de wrote:

• apic_set_fixmap();

• /*

• * Don't reread the APIC ID as it was already done from
  

• * check_x2apic() and the apic driver still is a x2APIC variant,
  

• * which fails to do the read after x2APIC was disabled.
  

• */
  

• apic_set_fixmap(false);

JFYI, I amended the commit with the fixlet below, to avoid the inevitable followup trivial patch:

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index b229648b7a18..803dcfb0e346 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1795,7 +1795,7 @@ static __init void x2apic_disable(void) __x2apic_disable(); /* * Don't reread the APIC ID as it was already done from - * check_x2apic() and the apic driver still is a x2APIC variant, + * check_x2apic() and the APIC driver still is a x2APIC variant, * which fails to do the read after x2APIC was disabled. */ apic_set_fixmap(false);

Thanks,

Ingo