linux-kernel - Re: [PATCH v15 04/12] x86/smpboot: Reference count on smpboot_setup_warm_reset

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Message-ID: <8D6C2EC1-7B53-410B-84C3-A1991A71DEB7@infradead.org>
Date:   Tue, 21 Mar 2023 11:43:58 +0000
From:   David Woodhouse <dwmw2@...radead.org>
To:     Borislav Petkov <bp@...en8.de>,
        Usama Arif <usama.arif@...edance.com>
CC:     tglx@...utronix.de, kim.phillips@....com, brgerst@...il.com,
        piotrgorski@...hyos.org, oleksandr@...alenko.name,
        arjan@...ux.intel.com, mingo@...hat.com,
        dave.hansen@...ux.intel.com, hpa@...or.com, x86@...nel.org,
        pbonzini@...hat.com, paulmck@...nel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        rcu@...r.kernel.org, mimoja@...oja.de, hewenliang4@...wei.com,
        thomas.lendacky@....com, seanjc@...gle.com, pmenzel@...gen.mpg.de,
        fam.zheng@...edance.com, punit.agrawal@...edance.com,
        simon.evans@...edance.com, liangma@...ngbit.com,
        gpiccoli@...lia.com, David Woodhouse <dwmw@...zon.co.uk>
Subject: Re: [PATCH v15 04/12] x86/smpboot: Reference count on smpboot_setup_warm_reset_vector()



On 21 March 2023 11:41:15 GMT, Borislav Petkov <bp@...en8.de> wrote:
>On Thu, Mar 16, 2023 at 10:21:01PM +0000, Usama Arif wrote:
>> From: David Woodhouse <dwmw@...zon.co.uk>
>> 
>> When bringing up a secondary CPU from do_boot_cpu(), the warm reset flag
>> is set in CMOS and the starting IP for the trampoline written inside the
>> BDA at 0x467. Once the CPU is running, the CMOS flag is unset and the
>> value in the BDA cleared.
>> 
>> To allow for parallel bringup of CPUs, add a reference count to track the
>> number of CPUs currently bring brought up, and clear the state only when
>
>s/bring //

"being", I think.