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Re: [tip:x86/apic] x86/acpi: Introduce persistent storage for cpuid <-> apicid mapping

From Thomas Gleixner <tglx@linutronix.de>
Newsgroups linux.kernel
Subject Re: [tip:x86/apic] x86/acpi: Introduce persistent storage for cpuid <-> apicid mapping
Date 2016-10-07 15:10 +0200
Message-ID <spD4v-QQ-75@gated-at.bofh.it> (permalink)
References (4 earlier) <sp8WJ-3H5-7@gated-at.bofh.it> <spbUB-5Qv-25@gated-at.bofh.it> <spooO-6tZ-13@gated-at.bofh.it> <spv6V-38J-1@gated-at.bofh.it> <spCUO-xF-9@gated-at.bofh.it>
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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.

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.

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.

Thanks,

	tglx

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Re: [tip:x86/apic] x86/acpi: Introduce persistent storage for cpuid  <-> apicid mapping Yinghai Lu <yinghai@kernel.org> - 2016-10-04 08:10 +0200
  Re: [tip:x86/apic] x86/acpi: Introduce persistent storage for cpuid  <-> apicid mapping Thomas Gleixner <tglx@linutronix.de> - 2016-10-05 16:10 +0200
    Re: [tip:x86/apic] x86/acpi: Introduce persistent storage for cpuid  <-> apicid mapping Yinghai Lu <yinghai@kernel.org> - 2016-10-06 07:00 +0200
      Re: [tip:x86/apic] x86/acpi: Introduce persistent storage for cpuid  <-> apicid mapping Dou Liyang <douly.fnst@cn.fujitsu.com> - 2016-10-06 10:10 +0200
        Re: [tip:x86/apic] x86/acpi: Introduce persistent storage for cpuid  <-> apicid mapping Yinghai Lu <yinghai@kernel.org> - 2016-10-06 23:30 +0200
          Re: [tip:x86/apic] x86/acpi: Introduce persistent storage for cpuid  <-> apicid mapping Dou Liyang <douly.fnst@cn.fujitsu.com> - 2016-10-07 06:40 +0200
            Re: [tip:x86/apic] x86/acpi: Introduce persistent storage for cpuid  <-> apicid mapping Thomas Gleixner <tglx@linutronix.de> - 2016-10-07 15:00 +0200
              Re: [tip:x86/apic] x86/acpi: Introduce persistent storage for cpuid  <-> apicid mapping Thomas Gleixner <tglx@linutronix.de> - 2016-10-07 15:10 +0200
                Re: [tip:x86/apic] x86/acpi: Introduce persistent storage for cpuid  <-> apicid mapping Yinghai Lu <yinghai@kernel.org> - 2016-10-07 21:00 +0200
                Re: [tip:x86/apic] x86/acpi: Introduce persistent storage for cpuid  <-> apicid mapping Dou Liyang <douly.fnst@cn.fujitsu.com> - 2016-10-08 07:30 +0200
          Re: [tip:x86/apic] x86/acpi: Introduce persistent storage for cpuid  <-> apicid mapping Thomas Gleixner <tglx@linutronix.de> - 2016-10-07 13:10 +0200
          Re: [tip:x86/apic] x86/acpi: Introduce persistent storage for cpuid  <-> apicid mapping Thomas Gleixner <tglx@linutronix.de> - 2016-10-07 13:10 +0200
        Re: [tip:x86/apic] x86/acpi: Introduce persistent storage for cpuid  <-> apicid mapping Thomas Gleixner <tglx@linutronix.de> - 2016-10-07 15:20 +0200
          Re: [tip:x86/apic] x86/acpi: Introduce persistent storage for cpuid  <-> apicid mapping Dou Liyang <douly.fnst@cn.fujitsu.com> - 2016-10-08 06:20 +0200

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