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Message-ID: <4dbdd277c4b26ae4b971a910209a3279f79f6837.camel@infradead.org>
Subject: Re: [PATCH v16 8/8] x86/smpboot: Allow parallel bringup for SEV-ES
From:   David Woodhouse <dwmw2@infradead.org>
To:     Borislav Petkov <bp@alien8.de>
Cc:     Usama Arif <usama.arif@bytedance.com>, tglx@linutronix.de,
        kim.phillips@amd.com, brgerst@gmail.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>
Date:   Thu, 23 Mar 2023 09:04:11 +0000
In-Reply-To: <20230323085138.GAZBwTGly7iOlvxrD4@fat_crate.local>
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         <20230322224735.GAZBuFh9ld6FuYEyoH@fat_crate.local>
         <70628793e6777d07f27f43152df497e780925d18.camel@infradead.org>
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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...
>=20
> 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.

But there is head64.c with examples. By 'cargo cult' I refer to the
process of copying what they do even if we don't really understand it.

I spotted that it builds with -pg, and that the functions in there are
tagged with __head to put them in the .head.text section. I didn't look
much further; there might be *other* details to copy=E2=80=A6 to 'cargo cul=
t'.


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