linux-kernel - Re: [patch] x86/smpboot: Disable parallel bootup if cc

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Message-ID: <871qiximen.ffs@tglx>
Date:   Tue, 30 May 2023 22:39:44 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Tom Lendacky <thomas.lendacky@....com>,
        Sean Christopherson <seanjc@...gle.com>
Cc:     "Kirill A. Shutemov" <kirill@...temov.name>,
        LKML <linux-kernel@...r.kernel.org>, x86@...nel.org,
        David Woodhouse <dwmw2@...radead.org>,
        Andrew Cooper <andrew.cooper3@...rix.com>,
        Brian Gerst <brgerst@...il.com>,
        Arjan van de Veen <arjan@...ux.intel.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Paul McKenney <paulmck@...nel.org>,
        Oleksandr Natalenko <oleksandr@...alenko.name>,
        Paul Menzel <pmenzel@...gen.mpg.de>,
        "Guilherme G. Piccoli" <gpiccoli@...lia.com>,
        Piotr Gorski <lucjan.lucjanov@...il.com>,
        Usama Arif <usama.arif@...edance.com>,
        Juergen Gross <jgross@...e.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        xen-devel@...ts.xenproject.org,
        Russell King <linux@...linux.org.uk>,
        Arnd Bergmann <arnd@...db.de>,
        linux-arm-kernel@...ts.infradead.org,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>, Guo Ren <guoren@...nel.org>,
        linux-csky@...r.kernel.org,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        linux-mips@...r.kernel.org,
        "James E.J. Bottomley" <James.Bottomley@...senpartnership.com>,
        Helge Deller <deller@....de>, linux-parisc@...r.kernel.org,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        linux-riscv@...ts.infradead.org,
        Mark Rutland <mark.rutland@....com>,
        Sabin Rapan <sabrapan@...zon.com>,
        "Michael Kelley (LINUX)" <mikelley@...rosoft.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>
Subject: Re: [patch] x86/smpboot: Disable parallel bootup if cc_vendor != NONE

On Tue, May 30 2023 at 15:03, Tom Lendacky wrote:
> On 5/30/23 14:51, Thomas Gleixner wrote:
>> That aside. From a semantical POV making this decision about parallel
>> bootup based on some magic CC encryption attribute is questionable.
>> 
>> I'm tending to just do the below and make this CC agnostic (except that
>> I couldn't find the right spot for SEV-ES to clear that flag.)
>
> Maybe in sme_sev_setup_real_mode() in arch/x86/realmode/init.c? You could 
> clear the flag within the CC_ATTR_GUEST_STATE_ENCRYPT check.

Eeew.

Can we please have a AMD SEV-ES init specific place and not hijack some
random code which has to check CC_ATTR_GUEST_STATE_ENCRYPT?

Thanks,

        tglx