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Date: Wed, 11 Sep 2024 16:51:28 +0100
From: Joey Gouly <joey.gouly@arm.com>
To: Marc Zyngier <maz@kernel.org>
Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
	kvm@vger.kernel.org, James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Oliver Upton <oliver.upton@linux.dev>,
	Zenghui Yu <yuzenghui@huawei.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Mark Brown <broonie@kernel.org>
Subject: Re: [PATCH v3 18/24] KVM: arm64: Split S1 permission evaluation into
 direct and hierarchical parts
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References: <20240911135151.401193-1-maz@kernel.org>
 <20240911135151.401193-19-maz@kernel.org>
 <20240911141513.GA1080224@e124191.cambridge.arm.com>
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In-Reply-To: <86o74u6vzu.wl-maz@kernel.org>

On Wed, Sep 11, 2024 at 04:38:45PM +0100, Marc Zyngier wrote:
> On Wed, 11 Sep 2024 15:15:13 +0100,
> Joey Gouly <joey.gouly@arm.com> wrote:
> > 
> > On Wed, Sep 11, 2024 at 02:51:45PM +0100, Marc Zyngier wrote:
> 
> [...]
> 
> > > +static void compute_s1_hierarchical_permissions(struct kvm_vcpu *vcpu,
> > > +						struct s1_walk_info *wi,
> > > +						struct s1_walk_result *wr,
> > > +						struct s1_perms *s1p)
> > > +{
> > 
> > How about:
> > 
> > 	if (wi->hpd)
> > 		return;
> 
> I was hoping not to add anything like this, because all the table bits
> are 0 (we simply don't collect them), and thus don't have any effect.

I just thought it was more obvious that they wouldn't apply in this case, don't
feel super strongly about it.

> 
> Or did you spot any edge case where that would result in in a
> different set of permissions?
> 
> Thanks,
> 
> 	M.
> 

Thanks,
Joey