Messages in this thread |  | | Subject | Re: [tip:x86/apic] x86/acpi: Introduce persistent storage for cpuid <-> apicid mapping | From | Dou Liyang <> | Date | Sat, 8 Oct 2016 13:22:56 +0800 |
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Hi tglx,
At 10/07/2016 09:00 PM, Thomas Gleixner wrote: > On Fri, 7 Oct 2016, Thomas Gleixner wrote: >> On Fri, 7 Oct 2016, Dou Liyang wrote: >>> Is it possible that the "-1/oxffffffff" could appear in the MADT which is one >>> of the ACPI tables? >> >> According to the SDM the x2apic id is a 32bit ID, so 0xffffffff is a >> legitimate value.
Yes, I see.
> > The ACPI spec says that bit 0 of the x2apic flags field tells whether the > logical processor is present or not. So the proper check for x2apic is that > flag. > > The lapic structure has the same flag, but the kernel ignores the flags for > both lapic and x2apic.
It seems the kernel uses the flags in this sentence:
enabled = processor->lapic_flags & ACPI_MADT_ENABLED;
> > I'm going to apply the minimal fix of checking for id == 0xff in > acpi_lapic_parse() for now, but this needs to be revisited and fixed > proper.
Yes, I will do it.
Thanks
Dou.
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