From: Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>
To: Andreas Herrmann
<andreas.herrmann-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
Cc: "iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org"
<iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>,
Rob Herring <robherring2-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
"linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org"
<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>
Subject: Re: [PATCH 3/5] iommu/arm-smmu: Introduce stream ID masking
Date: Tue, 8 Oct 2013 16:10:07 +0100 [thread overview]
Message-ID: <20131008151007.GD21189@mudshark.cambridge.arm.com> (raw)
In-Reply-To: <1381224444-27303-4-git-send-email-andreas.herrmann-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
On Tue, Oct 08, 2013 at 10:27:22AM +0100, Andreas Herrmann wrote:
> Ie. use a mask based on smr_mask_bits to map all stream IDs of an SMMU
> to one context.
>
> This behaviour is controlled per SMMU node with DT property
> "arm,smmu-mask-stream-ids" and is only allowed if just a single master
> is attached to an SMMU. If the option is specified, all stream-ids
> that are provided in DT for the single master have no relevance.
>
> This is useful/convenient if a master has more than 8 stream-ids or if
> not all stream-ids are known for a master device.
Hmmm, this really scares me. What's the use-case? I worry about people
inadvertently putting devices into an iommu domain because they happen to be
included in a mask. Your solution seems to be targetting a single master
with lots of IDs -- is this a PCI RC?
Will
next prev parent reply other threads:[~2013-10-08 15:10 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-08 9:27 [PATCH 0/5] iommu/arm-smmu: Misc modifications to support SMMUs on Calxeda ECX-2000 Andreas Herrmann
[not found] ` <1381224444-27303-1-git-send-email-andreas.herrmann-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
2013-10-08 9:27 ` [PATCH 1/5] iommu/arm-smmu: Introduce driver option handling Andreas Herrmann
[not found] ` <1381224444-27303-2-git-send-email-andreas.herrmann-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
2013-10-08 15:06 ` Will Deacon
[not found] ` <20131008150613.GC21189-MRww78TxoiP5vMa5CHWGZ34zcgK1vI+I0E9HWUfgJXw@public.gmane.org>
2013-10-08 15:16 ` Andreas Herrmann
2013-10-08 9:27 ` [PATCH 2/5] iommu/arm-smmu: Introduce bus notifier block Andreas Herrmann
2013-10-08 9:27 ` [PATCH 3/5] iommu/arm-smmu: Introduce stream ID masking Andreas Herrmann
[not found] ` <1381224444-27303-4-git-send-email-andreas.herrmann-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
2013-10-08 15:10 ` Will Deacon [this message]
[not found] ` <20131008151007.GD21189-MRww78TxoiP5vMa5CHWGZ34zcgK1vI+I0E9HWUfgJXw@public.gmane.org>
2013-10-08 15:20 ` Andreas Herrmann
2013-10-08 16:40 ` Andreas Herrmann
2013-10-08 16:59 ` Will Deacon
[not found] ` <20131008165920.GG21189-MRww78TxoiP5vMa5CHWGZ34zcgK1vI+I0E9HWUfgJXw@public.gmane.org>
2013-10-08 18:18 ` Sethi Varun-B16395
2013-10-08 18:43 ` Rob Herring
[not found] ` <52545266.6010400-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-10-09 10:09 ` Will Deacon
[not found] ` <20131009100917.GB5985-MRww78TxoiP5vMa5CHWGZ34zcgK1vI+I0E9HWUfgJXw@public.gmane.org>
2013-10-09 23:10 ` Andreas Herrmann
2013-10-09 22:55 ` Andreas Herrmann
2013-10-08 9:27 ` [PATCH 4/5] iommu/arm-smmu: Support buggy implementations where all config accesses are secure Andreas Herrmann
2013-10-08 9:27 ` [PATCH 5/5] ARM: dts: Add nodes for SMMUs on Calxeda ECX-2000 Andreas Herrmann
2013-10-08 10:31 ` [PATCH] documentation/iommu: Update description of ARM System MMU binding Andreas Herrmann
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