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From: Kevin Loughlin <kevinloughlin@google.com>
Date: Thu, 14 Mar 2024 08:57:04 -0700
Message-ID: <CAGdbjm+A2UwK0yYfA+AasxqjQJBfRE3k9ubpPcaVP9KJNinxHQ@mail.gmail.com>
Subject: Re: [PATCH v3] x86/asm: Force native_apic_mem_read to use mov
To: Adam Dunlap <acdunlap@google.com>
Cc: Ard Biesheuvel <ardb@kernel.org>, Dave Hansen <dave.hansen@intel.com>, 
	Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, 
	Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org, 
	"H. Peter Anvin" <hpa@zytor.com>, Nathan Chancellor <nathan@kernel.org>, 
	Nick Desaulniers <ndesaulniers@google.com>, Bill Wendling <morbo@google.com>, 
	Justin Stitt <justinstitt@google.com>, "Peter Zijlstra (Intel)" <peterz@infradead.org>, 
	Arjan van de Ven <arjan@linux.intel.com>, Wei Liu <wei.liu@kernel.org>, linux-kernel@vger.kernel.org, 
	llvm@lists.linux.dev, Jacob Xu <jacobhxu@google.com>, Alper Gun <alpergun@google.com>, 
	Peter Gonda <pgonda@google.com>
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On Fri, Feb 9, 2024 at 10:20=E2=80=AFAM Adam Dunlap <acdunlap@google.com> w=
rote:
>
> On Fri, Feb 9, 2024 at 7:22=E2=80=AFAM Ard Biesheuvel <ardb@kernel.org> w=
rote:
> >
> > this seems like the kind of thing we'll want in -stable in case folks
> > are compiling stable kernels with new clangs.
>
> That makes sense. Note that there was another patch accepted recently
> that fixed another
> clang-with-SEV problem [1], so they should probably be backported to
> the same stable
> branches since neither is that useful without the other.
>
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?i=
d=3D1c811d403afd73f04bde82b83b24c754011bd0e8

Agreed; clang builds of SEV-SNP guests will need both this patch and
[1]. If an additional patch [2] also gets merged, we may want to do
the same for [2] as well.

[2] https://lore.kernel.org/lkml/20240313121546.2964854-1-kevinloughlin@goo=
gle.com/