Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Mon, 16 Nov 2020 17:56:36 +0000
From:   David Brazdil <dbrazdil@google.com>
To:     Marc Zyngier <maz@kernel.org>
Cc:     kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, James Morse <james.morse@arm.com>,
        Julien Thierry <julien.thierry.kdev@gmail.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>, Dennis Zhou <dennis@kernel.org>,
        Tejun Heo <tj@kernel.org>, Christoph Lameter <cl@linux.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Quentin Perret <qperret@google.com>,
        Andrew Scull <ascull@google.com>,
        Andrew Walbran <qwandor@google.com>, kernel-team@android.com
Subject: Re: [PATCH v1 10/24] kvm: arm64: Extract parts of el2_setup into a
 macro
Message-ID: <20201116175636.qmp5iws6gq7a7syi@google.com>
References: <20201109113233.9012-1-dbrazdil@google.com>
 <20201109113233.9012-11-dbrazdil@google.com>
 <a6f5d318eb7e7adde2106df068121b48@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <a6f5d318eb7e7adde2106df068121b48@kernel.org>
Precedence: bulk

Hi Marc,

> > +	 * Check for VHE being present. x2 being non-zero indicates that we
> > +	 * do have VHE, and that the kernel is intended to run at EL2.
> >  	 */
> >  	mrs	x2, id_aa64mmfr1_el1
> >  	ubfx	x2, x2, #ID_AA64MMFR1_VHE_SHIFT, #4
> > -#else
> > -	mov	x2, xzr
> > -#endif
> > +	cbz	x2, el2_setup_nvhe
> 
> What initialises x2 to zero when CONFIG_VHE is disabled?

There is no need for x2 anymore, the nVHE code just falls through. Basically:

	el2_setup:
		< check CurrentEL >
		b.eq	1f
		ret
	1:
	#ifdef CONFIG_VHE
		< check has VHE >
		cbz	el2_setup_nvhe
		< VHE setup >
		ret
	#endif
	el2_setup_nvhe:
		< nVHE setup >
		eret

-David