Received-SPF: pass (google.com: domain of linux-kernel+bounces-202612-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
Date: Wed, 5 Jun 2024 13:31:38 +0100
From: Mark Brown <broonie@kernel.org>
To: Marc Zyngier <maz@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Oliver Upton <oliver.upton@linux.dev>,
	James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Fuad Tabba <tabba@google.com>, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev
Subject: Re: [PATCH 2/4] arm64/fpsimd: Discover maximum vector length
 implemented by any CPU
Message-ID: <1875ba4e-02c7-4331-b9c6-7ab68d2157b3@sirena.org.uk>
References: <20240605-kvm-arm64-fix-pkvm-sve-vl-v1-0-680d6b43b4c1@kernel.org>
 <20240605-kvm-arm64-fix-pkvm-sve-vl-v1-2-680d6b43b4c1@kernel.org>
 <86bk4flh9b.wl-maz@kernel.org>
Precedence: bulk
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha512;
	protocol="application/pgp-signature"; boundary="ysVZwPn+MwR2sALq"
Content-Disposition: inline
In-Reply-To: <86bk4flh9b.wl-maz@kernel.org>


--ysVZwPn+MwR2sALq
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline

On Wed, Jun 05, 2024 at 01:13:20PM +0100, Marc Zyngier wrote:
> Mark Brown <broonie@kernel.org> wrote:

> > +	/*
> > +	 * pKVM allocates and uses storage for host state based on the
> > +	 * largest per-PE VL, reject new PEs with a larger maximum.
> > +	 */
> > +	if (is_protected_kvm_enabled()) {
> > +		if (max_vl > info->max_cpu_vl) {
> > +			pr_warn("%s: cpu%d: would increase maximum VL\n",
> > +				info->name, smp_processor_id());
> > +			return -EINVAL;
> > +		}
> > +	}

> Once protected mode is enabled, no new CPU can be booted (see
> psci_relay.c::psci_cpu_on()).

Ah, that's a bit easier.  Might still be worth keeping the check just in
case that changes or we acquire some further use of this value but it's
not currently needed and the comment could be updated.

--ysVZwPn+MwR2sALq
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----

iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmZgWqkACgkQJNaLcl1U
h9AyJQf+MY+KJBHvUdEZTyWsyWafn1JsdBv59+XpSqS/no1XW//XIGvcCvJvQ9/I
/d+4iNDJO5KfECkTL2Zsp4w0k5ogpe14dxnNoSAk6coLY1C9O/QlVZveuR96VMEQ
kFIqT86CC8zZ53FMJkiSPSvh4xCot2/jVaDEIZ7Hc6XTy4iAWZCcmt0NS4TYtIpf
QtvfMeVCkKft6/Na8pjSWKlKkiNRxPbNxaXFBsKXdeltidzOuXdX/JS4J0QtANjo
byDIxgwAy453h+6JGn5/9lqtVP/33/ZGAqqakPPhxVZRfg09C8+RuT/GVcs8r6Xz
SAo4rWVbNS9hGnQxwuEOvSpQnnx/EQ==
=kQnc
-----END PGP SIGNATURE-----

--ysVZwPn+MwR2sALq--