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From:   Brian Gerst <brgerst@gmail.com>
Date:   Thu, 23 Mar 2023 10:23:02 -0400
Message-ID: <CAMzpN2guz4HTQ8uir9Q=xrUpCYyBfuG2zGSJsakaqY7_OvxCPQ@mail.gmail.com>
Subject: Re: [PATCH v16 8/8] x86/smpboot: Allow parallel bringup for SEV-ES
To:     David Woodhouse <dwmw2@infradead.org>
Cc:     Borislav Petkov <bp@alien8.de>,
        Usama Arif <usama.arif@bytedance.com>, tglx@linutronix.de,
        kim.phillips@amd.com, piotrgorski@cachyos.org,
        oleksandr@natalenko.name, arjan@linux.intel.com, mingo@redhat.com,
        dave.hansen@linux.intel.com, hpa@zytor.com, x86@kernel.org,
        pbonzini@redhat.com, paulmck@kernel.org,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        rcu@vger.kernel.org, mimoja@mimoja.de, hewenliang4@huawei.com,
        thomas.lendacky@amd.com, seanjc@google.com, pmenzel@molgen.mpg.de,
        fam.zheng@bytedance.com, punit.agrawal@bytedance.com,
        simon.evans@bytedance.com, liangma@liangbit.com,
        gpiccoli@igalia.com, Sabin Rapan <sabrapan@amazon.com>
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On Thu, Mar 23, 2023 at 5:04=E2=80=AFAM David Woodhouse <dwmw2@infradead.or=
g> wrote:
>
> On Thu, 2023-03-23 at 09:51 +0100, Borislav Petkov wrote:
> > On Thu, Mar 23, 2023 at 08:32:49AM +0000, David Woodhouse wrote:
> > > and maybe find some other stuff to cargo-cult to make it safe to run
> > > C code that early...
> >
> > I'm trying to have less shit asm, not more if possible. We've been
> > aiming to convert stuff to C for years.
>
> Absolutely, I understand. There are a few hoops we have to jump through
> to be able to run C code this early, but it's worth it.
>
> > WTF are you calling cargo-cult?
>
> Off the top of my head, I don't actually *remember* all the hoops we
> have to jump through to run C code this early.

Making sure that the stack protector is either disabled or properly
set up, and disabling any instrumentation/profiling/debug crap that
isn't initialized yet.

--
Brian Gerst