From mboxrd@z Thu Jan  1 00:00:00 1970
From: marc.zyngier@arm.com (Marc Zyngier)
Date: Wed, 22 Mar 2017 09:58:36 +0000
Subject: [PATCH] KVM: arm/arm64: vgic: Fix GICC_PMR uaccess on GICv3 and
 clarify ABI
In-Reply-To: <20170321210522.8362-1-cdall@linaro.org>
References: <20170321210522.8362-1-cdall@linaro.org>
Message-ID: <15b51bbf-aeb9-fe7c-1c64-66a4c40faa91@arm.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On 21/03/17 21:05, Christoffer Dall wrote:
> As an oversight, for GICv2, we accidentally export the GICC_PMR register
> in the format of the GICH_VMCR.VMPriMask field in the lower 5 bits of a
> word, meaning that userspace must always use the lower 5 bits to
> communicate with the KVM device and must shift the value left by 3
> places to obtain the actual priority mask level.
> 
> Since GICv3 supports the full 8 bits of priority masking in the ICH_VMCR,
> we have to fix the value we export when emulating a GICv2 on top of a
> hardware GICv3 and exporting the emulated GICv2 state to userspace.
> 
> Take the chance to clarify this aspect of the ABI.
> 
> Signed-off-by: Christoffer Dall <cdall@linaro.org>

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>

	M.
-- 
Jazz is not dead. It just smells funny...