linux-kernel - Re: [PATCH] x86/cpuid: Deal with broken firmware once more

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Date:   Thu, 10 Nov 2016 05:50:16 -0500
From:   "Charles (Chas) Williams" <ciwillia@...cade.com>
To:     "M. Vefa Bicakci" <m.v.b@...box.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>
CC:     "x86@...nel.org" <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Borislav Petkov <bp@...en8.de>
Subject: Re: [PATCH] x86/cpuid: Deal with broken firmware once more



On 11/09/2016 10:57 PM, M. Vefa Bicakci wrote:
> [    0.002000] mvb: CPU: Physical Processor ID: 0
> [    0.002000] mvb: CPU: Processor Core ID: 0
> [    0.002000] mvb: identify_cpu:1112: c: ffff880013b0a040, c->logical_proc_id: 65535
> [    0.002000] mvb: __default_cpu_present_to_apicid:612: Returning 65535! mps_cpu: 1, nr_cpu_ids: 2, cpu_present(mps_cpu): 1
> [    0.002000] smpboot: mvb: topology_update_package_map:270: cpu: 1, pkg: 4095
> [    0.002000] smpboot: APIC(ffff) Converting physical 4095 to logical package 0
> [    0.002000] smpboot: mvb: topology_update_package_map:305: cpu: 1, cpu_data(cpu).logical_proc_id: 0

This seems strange.  0xffff is BAD_APICID.  Why didn't this fail here:

         for_each_present_cpu(cpu) {
                 unsigned int apicid = apic->cpu_present_to_apicid(cpu);

                 if (apicid == BAD_APICID || !apic->apic_id_valid(apicid))  <<<<<<<<<<
                         continue;
                 if (!topology_update_package_map(apicid, cpu))
                         continue;

topology_update_package_map() should never have been called?