Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:4 as permitted sender) client-ip=2620:137:e000::3:4;
Date:   Thu, 14 Sep 2023 11:32:12 +0100
From:   Mark Brown <broonie@kernel.org>
To:     Oliver Upton <oliver.upton@linux.dev>
Cc:     Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] KVM: arm64: Only default to enabling SVE when present
Message-ID: <d090e3db-ebed-4cc8-a1f8-a2c15f8a39b1@sirena.org.uk>
References: <20230913-kvm-arm64-fp-init-v1-1-8ce9ba1cc4c4@kernel.org>
 <ZQJODdfwZLxc9o1l@linux.dev>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha512;
        protocol="application/pgp-signature"; boundary="z0nQ7h2X83FBCQV9"
Content-Disposition: inline
In-Reply-To: <ZQJODdfwZLxc9o1l@linux.dev>
Precedence: bulk


--z0nQ7h2X83FBCQV9
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline

On Thu, Sep 14, 2023 at 12:04:29AM +0000, Oliver Upton wrote:
> On Wed, Sep 13, 2023 at 07:34:16PM +0100, Mark Brown wrote:

> > -		if (!vcpu_has_sve(vcpu) ||
> > -		    (vcpu->arch.fp_state != FP_STATE_GUEST_OWNED))
> > +		if (cpus_have_final_cap(ARM64_SVE) &&
> > +		    (!vcpu_has_sve(vcpu) ||
> > +		     (vcpu->arch.fp_state != FP_STATE_GUEST_OWNED)))

> vcpu_has_sve() already tests system_supports_sve(), so I don't believe
> this hunk is necessary.

That'll mean that the first branch of the || should always return true
on systems without SVE so we'll set CPTR_EL2_TZ, and there's also the
check for guest ownership as well.

--z0nQ7h2X83FBCQV9
Content-Type: application/pgp-signature; name="signature.asc"

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

iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmUC4SsACgkQJNaLcl1U
h9CFOQf/QechB02CRL9EgDHH6cg1JKq0BnYtRhWUwz4dRh8P9+AOR9+EGb+HsFXO
fEDX/KBk6rjyAQxOdW4h9Xeiz3FwDwzqp5bByWlQqCBahox0Hu9tVq2B592IhzOm
Iskr9i0ysKw/oJ40YgBYB2dMuAEoS3kCk3rLGhzog4N59jzt3l/NkKt4SHkhjwtE
83pIAzF+TGu2g2fzMaDRYdGyA/RobSDnxGyLrDvSRyq4PVHIAzHWhS2+e5yoNid7
tNeo65Rxjumu3e8DdGhQarWfW9Rb51cWFIGEw3SqYn73DdnV7DBxMSVPaq1McW3n
cz1MP4Y8H+8mm+6rOtv5S4/SzzfEyQ==
=Ph8R
-----END PGP SIGNATURE-----

--z0nQ7h2X83FBCQV9--