Hi Alex, On Wed, Jul 09, 2014 at 03:13:04PM +0100, Alex Williamson wrote: > On Wed, 2014-07-09 at 14:26 +0100, Will Deacon wrote: > > pci_find_dma_isolation_root doesn't exist in any of the trees I have. Alex, > > is this queued anywhere and do I actually need it? > > That function was in the v3 DMA alias series, in v4 it got replaced. > iommu_group_get_for_pci_dev() is the common function for finding or > creating a group for a device and pci_for_each_dma_alias() is the > interface to walk each alias in a PCI topology. The pci_ interface is > in 3.16-rc and the iommu_ pieces are current in next via the iommu tree. > > > The purpose of this code is to find the requester ID of a device as it > > appears at the host controller. At this point, we can map it (via firmware > > tables that are TBD) to a Stream ID for the SMMU. It looks to me like > > pci_for_each_dma_alias walks over non-transparent PCI bridges correctly, so > > the callback I provide just updates the alias until the walk has completed. > > Yep, that's the intended usage. There are cases in VT-d where it wants > to add context entries for every alias and cases elsewhere that we just > want the final alias. pci_for_each_dma_alias() is meant to fit both use > cases. Thanks,
I'm looking at moving the arm-smmu driver over to using iommu_group_get_for_dev, but I've hit a slight snag. Once I have the group, I actually need to get hold of the alias for that group, since that will be converted into a StreamID used to program the SMMU. I can do this by open-coding my own version of iommu_group_get_for_pci_dev, but that's pretty horrible. What's the best way to get hold of the alias for a given group? Cheers, Will _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
