On Fri, Sep 27, 2024 at 01:50:52PM +0000, Mostafa Saleh wrote: > My understanding of IOMMUFD is very little, but AFAICT, that means that > it’s assumed that each device can only have one stream ID(RID)? > > As I can see in patch 17 in arm_smmu_convert_viommu_vdev_id(), it > converts the virtual ID to a physical one using master->streams[0].id. > > Is that correct or am I missing something? > > As I am looking at similar problem for paravirtual IOMMU with pKVM, where > the UAPI would be something similar to: > > GET_NUM_END_POINTS(dev) => nr_sids > > SET_END_POINT_VSID(dev, sid_index, vsid) > > Similar to what VFIO does with IRQs. > > As a device can have many SIDs. We don't support multi SID through this interface, at least in this version. To do multi-sid you have to inform the VM of all the different pSIDs the device has and then setup the vSID/pSID translation to map them all to the HW invalidation logic. Which is alot more steps, and we have no use case right now. Multi-sid is also not something I expect to see in any modern PCI device, and this is VFIO PCI... Jason
