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

From	Dou Liyang <douly.fnst@cn.fujitsu.com>
Newsgroups	linux.kernel
Subject	Re: [tip:x86/apic] x86/acpi: Introduce persistent storage for cpuid <-> apicid mapping
Date	2016-10-08 07:30 +0200
Message-ID	<spSmS-2SF-21@gated-at.bofh.it> (permalink)
References	(5 earlier) <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> <spD4v-QQ-75@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

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.

Thread

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

csiph-web