From: James Morse <james.morse@arm.com>
To: Marc Zyngier <maz@kernel.org>
Cc: kvm@vger.kernel.org, Suzuki K Poulose <suzuki.poulose@arm.com>,
Christoffer Dall <Christoffer.Dall@arm.com>,
stable@vger.kernel.org,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/3] KVM: arm/arm64: Properly handle faulting of device mappings
Date: Thu, 12 Dec 2019 15:35:10 +0000 [thread overview]
Message-ID: <98c0018d-1a32-c775-04c2-36440221709e@arm.com> (raw)
In-Reply-To: <20191211165651.7889-2-maz@kernel.org>
Hi Marc,
On 11/12/2019 16:56, Marc Zyngier wrote:
> A device mapping is normally always mapped at Stage-2, since there
> is very little gain in having it faulted in.
>
> Nonetheless, it is possible to end-up in a situation where the device
> mapping has been removed from Stage-2 (userspace munmaped the VFIO
> region, and the MMU notifier did its job), but present in a userspace
> mapping (userpace has mapped it back at the same address). In such
> a situation, the device mapping will be demand-paged as the guest
> performs memory accesses.
>
> This requires to be careful when dealing with mapping size, cache
> management, and to handle potential execution of a device mapping.
Reviewed-by: James Morse <james.morse@arm.com>
Thanks,
James
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next prev parent reply other threads:[~2019-12-12 15:35 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-11 16:56 [PATCH 0/3] KVM: arm/arm64: user_mem_abort() assorted fixes Marc Zyngier
2019-12-11 16:56 ` [PATCH 1/3] KVM: arm/arm64: Properly handle faulting of device mappings Marc Zyngier
2019-12-11 17:53 ` Alexandru Elisei
2019-12-11 18:01 ` Marc Zyngier
2019-12-12 15:35 ` James Morse [this message]
2019-12-13 8:29 ` Christoffer Dall
2019-12-13 9:28 ` Marc Zyngier
2019-12-13 11:14 ` Christoffer Dall
2019-12-16 10:31 ` Marc Zyngier
2019-12-18 15:13 ` Christoffer Dall
2019-12-11 16:56 ` [PATCH 2/3] KVM: arm/arm64: Re-check VMA on detecting a poisoned page Marc Zyngier
2019-12-12 11:33 ` Marc Zyngier
2019-12-12 15:34 ` James Morse
2019-12-12 15:40 ` Marc Zyngier
2019-12-13 9:25 ` Christoffer Dall
2019-12-13 9:22 ` Christoffer Dall
2019-12-16 18:29 ` James Morse
2019-12-11 16:56 ` [PATCH 3/3] KVM: arm/arm64: Drop spurious message when faulting on a non-existent mapping Marc Zyngier
2019-12-13 9:26 ` Christoffer Dall
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