Messages in this thread | | | Date | Tue, 22 Mar 2022 09:53:29 +0000 | Subject | Re: [PATCH v2 1/2] iommu: Add capability for pre-boot DMA protection | From | Robin Murphy <> |
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On 2022-03-22 09:14, Christoph Hellwig wrote: > On Fri, Mar 18, 2022 at 05:42:57PM +0000, Robin Murphy wrote: >> VT-d's dmar_platform_optin() actually represents a combination of >> properties fairly well standardised by Microsoft as "Pre-boot DMA >> Protection" and "Kernel DMA Protection"[1]. As such, we can provide >> interested consumers with an abstracted capability rather than >> driver-specific interfaces that won't scale. We name it for the former >> aspect since that's what external callers are most likely to be >> interested in; the latter is for the IOMMU layer to handle itself. >> >> Also use this as an opportunity to draw a line in the sand and add a >> new interface so as not to introduce any more callers of iommu_capable() >> which I also want to get rid of. For now it's a quick'n'dirty wrapper >> function, but will evolve to subsume the internal interface in future. >> >> [1] https://docs.microsoft.com/en-us/windows-hardware/design/device-experiences/oem-kernel-dma-protection >> >> Suggested-by: Christoph Hellwig <hch@lst.de> >> Signed-off-by: Robin Murphy <robin.murphy@arm.com> > > I can't really think of a way in which I suggested this, but it does > looks like a good interface:
Well, you were the first to say it should be abstracted[1], and since my initial thought that it could be hidden completely didn't pan out, I felt I should give you credit for being right all along :)
> Reviewed-by: Christoph Hellwig <hch@lst.de>
Thanks!
Robin.
[1] https://lore.kernel.org/linux-iommu/YjDDUUeZ%2FdvUZoDN@infradead.org/
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