On Wed, Jan 22, 2014 at 03:33:52PM +0000, Will Deacon wrote: > On Wed, Jan 22, 2014 at 01:54:11PM +0000, Varun Sethi wrote: > > > > > Ok, so are you suggesting that we perform the isolation mapping in > > > > > arm_smmu_add_device and drop the notifier altogether? > > > > I think that should be fine, until we want to delay mapping creation > > > > till driver bind time. > > > > > > Is there a hard dependency on that? > > > > > Not sure, may be Andreas can answer that. > > Ok. Andreas? I would have thought doing this *earlier* shouldn't be a > problem (the DMA ops must be swizzled before the driver is probed).
Yes, I think, there is no hard dependency. (But still have to double check whether arm_smmu_add_device can be used instead of the notifier. Will finally see this when doing some tests.) > > > > But the "isolate device" property should dictate iommu group creation. > > > > > > The reason we added automatic group creation (per-device) is for VFIO, > > > which expects all devices to be in a group regardless of the device > > > isolation configuration. > > > > > IIUC, with the "isolate devices" property we ensure that there would be > > independent SMR and S2CR per device. Is that correct? > > Yes, as part of giving them independent sets of page tables. Initially these > tables don't have any valid mappings, but the dma-mapping API will populate > them in response to dma_map_*/dma_alloc/etc. > > Not sure what this has to do with us putting devices into their own > groups... > > Will Andreas _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
