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Groups > linux.kernel > #1448763
| From | Mitchel Humpherys <mitchelh@codeaurora.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v3 0/6] Add support for privileged mappings |
| Date | 2016-07-22 22:40 +0200 |
| Message-ID | <rXPoK-2cw-3@gated-at.bofh.it> (permalink) |
| References | <rWJY5-fG-19@gated-at.bofh.it> <rXLXQ-8gM-13@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Fri, Jul 22 2016 at 05:51:07 PM, Will Deacon <will.deacon@arm.com> wrote: > On Tue, Jul 19, 2016 at 01:36:49PM -0700, Mitchel Humpherys wrote: >> The following patch to the ARM SMMU driver: >> >> commit d346180e70b91b3d5a1ae7e5603e65593d4622bc >> Author: Robin Murphy <robin.murphy@arm.com> >> Date: Tue Jan 26 18:06:34 2016 +0000 >> >> iommu/arm-smmu: Treat all device transactions as unprivileged >> >> started forcing all SMMU transactions to come through as "unprivileged". >> The rationale given was that: >> >> (1) There is no way in the IOMMU API to even request privileged mappings. >> >> (2) It's difficult to implement a DMA mapper that correctly models the >> ARM VMSAv8 behavior of unprivileged-writeable => >> privileged-execute-never. >> >> This series rectifies (1) by introducing an IOMMU API for privileged >> mappings and implements it in io-pgtable-arm. >> >> This series rectifies (2) by introducing a new dma attribute >> (DMA_ATTR_PRIVILEGED) for users of the DMA API that need privileged >> mappings which are inaccessible to lesser-privileged execution levels, and >> implements it in the arm64 IOMMU DMA mapper. The one known user (pl330.c) >> is converted over to the new attribute. >> >> Jordan and Jeremy can provide more info on the use case if needed, but the >> high level is that it's a security feature to prevent attacks such as [1]. > > This all looks good to me: > > Acked-by: Will Deacon <will.deacon@arm.com> > > It looks pretty fiddly to merge, however. How are you planning to get > this upstream? Fiddly in what way? Do you mean in relation to "dma-mapping: Use unsigned long for dma_attrs" [1]? I admit I wasn't aware of that activity until Robin mentioned it. It looks like it's merged on next/master, shall I rebase/rework on that and resend? [1] https://lkml.org/lkml/2016/7/13/198 -Mitch -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
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[PATCH v3 0/6] Add support for privileged mappings Mitchel Humpherys <mitchelh@codeaurora.org> - 2016-07-19 22:40 +0200
[PATCH v3 3/6] common: DMA-mapping: add DMA_ATTR_PRIVILEGED attribute Mitchel Humpherys <mitchelh@codeaurora.org> - 2016-07-19 22:40 +0200
[PATCH v3 1/6] iommu: add IOMMU_PRIV attribute Mitchel Humpherys <mitchelh@codeaurora.org> - 2016-07-19 22:40 +0200
[PATCH v3 2/6] iommu/io-pgtable-arm: add support for the IOMMU_PRIV flag Mitchel Humpherys <mitchelh@codeaurora.org> - 2016-07-19 22:40 +0200
Re: [PATCH v3 0/6] Add support for privileged mappings Will Deacon <will.deacon@arm.com> - 2016-07-22 19:00 +0200
Re: [PATCH v3 0/6] Add support for privileged mappings Mitchel Humpherys <mitchelh@codeaurora.org> - 2016-07-22 22:40 +0200
Re: [PATCH v3 0/6] Add support for privileged mappings Will Deacon <will.deacon@arm.com> - 2016-07-25 12:00 +0200
Re: [PATCH v3 0/6] Add support for privileged mappings Mitchel Humpherys <mitchelh@codeaurora.org> - 2016-07-25 21:10 +0200
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