From: marc.zyngier@arm.com (Marc Zyngier)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] KVM: arm/arm64: vgic: Fix GICC_PMR uaccess on GICv3 and clarify ABI
Date: Wed, 22 Mar 2017 09:58:36 +0000 [thread overview]
Message-ID: <15b51bbf-aeb9-fe7c-1c64-66a4c40faa91@arm.com> (raw)
In-Reply-To: <20170321210522.8362-1-cdall@linaro.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...
prev parent reply other threads:[~2017-03-22 9:58 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-21 21:05 [PATCH] KVM: arm/arm64: vgic: Fix GICC_PMR uaccess on GICv3 and clarify ABI Christoffer Dall
2017-03-22 9:58 ` Marc Zyngier [this message]
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