Messages in this thread | | | Subject | Re: [PATCH 1/4] iommu: Add iommu_device_group callback and iommu_group sysfs entry | From | David Woodhouse <> | Date | Thu, 01 Dec 2011 23:14:17 +0000 |
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On Thu, 2011-12-01 at 07:34 -0700, Alex Williamson wrote: > > Btw, did we get a quirk for the Ricoh multi-function devices which all > > need to be in the same group because they do all their DMA from function > > zero? I think we need another similar quirk for a Marvell SATA > > controller which seems to do its AHCI DMA from its IDE function; see > > https://bugzilla.redhat.com/757166 > > No, as I mentioned, groups are currently for iommu_ops, not dma_ops,
That doesn't matter. There are multiple devices which do all their DMA from the same source-id, and which have to be handled together. It doesn't *matter* that it's a hardware bug in this case, and it's just because they're multiple PCI devices behind a PCIe bridge in the other case. The grouping code needs to handle it, whether it's for the benefit of iommu_ops, dma_ops, or both.
> though it makes sense that iommu drivers could use the group info or > create common quirk infrastructure for handling broken devices like > these.
Well, I think we mostly have a consensus that dma_ops should be implemented *using* iommu_ops; I'd rather be trying to make things *consistent* between the two rather than building up the differences.
So I'd definitely go for your "use the group info" option. It is the *same* info, and needs the *same* quirks.
-- dwmw2
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