Re: [PATCH v13 11/40] arm64/gcs: Provide basic EL2 setup to allow GCS usage at EL0 and EL1

From: Marc Zyngier <maz@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Nathan Chancellor <nathan@kernel.org>,
	Mark Brown <broonie@kernel.org>, Will Deacon <will@kernel.org>,
	Jonathan Corbet <corbet@lwn.net>,
	Andrew Morton <akpm@linux-foundation.org>,
	Oliver Upton <oliver.upton@linux.dev>,
	James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Arnd Bergmann <arnd@arndb.de>, Oleg Nesterov <oleg@redhat.com>,
	Eric Biederman <ebiederm@xmission.com>,
	Shuah Khan <shuah@kernel.org>,
	"Rick P. Edgecombe" <rick.p.edgecombe@intel.com>,
	Deepak Gupta <debug@rivosinc.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	Szabolcs Nagy <Szabolcs.Nagy@arm.com>,
	Kees Cook <kees@kernel.org>, "H.J. Lu" <hjl.tools@gmail.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
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	Yury Khrustalev <yury.khrustalev@arm.com>,
	Wilco Dijkstra <wilco.dijkstra@arm.com>,
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Subject: Re: [PATCH v13 11/40] arm64/gcs: Provide basic EL2 setup to allow GCS usage at EL0 and EL1
Date: Fri, 11 Oct 2024 13:55:05 +0100	[thread overview]
Message-ID: <86h69i6bpy.wl-maz@kernel.org> (raw)
In-Reply-To: <ZwgMBAhR5-5R5EYC@arm.com>

On Thu, 10 Oct 2024 18:16:52 +0100,
Catalin Marinas <catalin.marinas@arm.com> wrote:
> 
> On Thu, Oct 10, 2024 at 04:18:13PM +0100, Marc Zyngier wrote:
> > From 20c98d2647c11db1e40768f92c5998ff5d764a3a Mon Sep 17 00:00:00 2001
> > From: Marc Zyngier <maz@kernel.org>
> > Date: Thu, 10 Oct 2024 16:13:26 +0100
> > Subject: [PATCH] KVM: arm64: Shave a few bytes from the EL2 idmap code
> > 
> > Our idmap is becoming too big, to the point where it doesn't fit in
> > a 4kB page anymore.
> > 
> > There are some low-hanging fruits though, such as the el2_init_state
> > horror that is expanded 3 times in the kernel. Let's at least limit
> > ourselves to two copies, which makes the kernel link again.
> > 
> > At some point, we'll have to have a better way of doing this.
> > 
> > Reported-by: Nathan Chancellor <nathan@kernel.org>
> > Signed-off-by: Marc Zyngier <maz@kernel.org>
> > Link: https://lore.kernel.org/r/20241009204903.GA3353168@thelio-3990X
> 
> Thanks Marc for the quick fix. It looks fine to me, it will keep the
> linker quiet for a while. I pushed it to arm64 for-kernelci for the time
> being, see if anything falls apart. I'll apply it properly once it gets
> a bit more testing.

Works for me. Bu if that helps, I can also queue it as a KVM fix for
6.12, leaving the GCS branch unencumbered. Just let me know.

	M.

-- 
Without deviation from the norm, progress is not possible.