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@xxxxxx> > Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx> I can't really think of a way in which I suggested this, but it does looks like a good interface: Reviewed-by: Christoph Hellwig <hch@xxxxxx>
