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Date:   Tue, 9 Feb 2021 12:23:04 +0000
From:   Will Deacon <will@kernel.org>
To:     Quentin Perret <qperret@google.com>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Marc Zyngier <maz@kernel.org>,
        James Morse <james.morse@arm.com>,
        Julien Thierry <julien.thierry.kdev@gmail.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Rob Herring <robh+dt@kernel.org>,
        Frank Rowand <frowand.list@gmail.com>,
        devicetree@vger.kernel.org, android-kvm@google.com,
        linux-kernel@vger.kernel.org, kernel-team@android.com,
        kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org,
        Fuad Tabba <tabba@google.com>,
        Mark Rutland <mark.rutland@arm.com>,
        David Brazdil <dbrazdil@google.com>
Subject: Re: [RFC PATCH v2 16/26] KVM: arm64: Prepare Hyp memory protection
Message-ID: <20210209122303.GA27058@willie-the-truck>
References: <20210108121524.656872-1-qperret@google.com>
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 <20210203143709.GA18907@willie-the-truck>
 <YBvQrHdbiNTSLQq6@google.com>
 <YCJdPXuGr9kCIKVM@google.com>
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On Tue, Feb 09, 2021 at 10:00:29AM +0000, Quentin Perret wrote:
> On Thursday 04 Feb 2021 at 10:47:08 (+0000), Quentin Perret wrote:
> > On Wednesday 03 Feb 2021 at 14:37:10 (+0000), Will Deacon wrote:
> > > > +static void handle___pkvm_init(struct kvm_cpu_context *host_ctxt)
> > > > +{
> > > > +	DECLARE_REG(phys_addr_t, phys, host_ctxt, 1);
> > > > +	DECLARE_REG(unsigned long, size, host_ctxt, 2);
> > > > +	DECLARE_REG(unsigned long, nr_cpus, host_ctxt, 3);
> > > > +	DECLARE_REG(unsigned long *, per_cpu_base, host_ctxt, 4);
> > > > +
> > > > +	cpu_reg(host_ctxt, 1) = __pkvm_init(phys, size, nr_cpus, per_cpu_base);
> > > 
> > > __pkvm_init() doesn't return, so I think this assignment back into host_ctxt
> > > is confusing.
> > 
> > Very good point, I'll get rid of this.
> 
> Actually not, I think I'll leave it like that. __pkvm_init can return an
> error, which is why I did this in the first place And it is useful for
> debugging to have it propagated back to the host.

Good point, but please add a comment!

Will