On Fri, Oct 25, 2024 at 03:54:44PM +1100, Alexey Kardashevskiy wrote: > On 22/10/24 11:20, Nicolin Chen wrote: > > Following the previous vIOMMU series, this adds another vDEVICE structure, > > representing the association from an iommufd_device to an iommufd_viommu. > > This gives the whole architecture a new "v" layer: > > _______________________________________________________________________ > > | iommufd (with vIOMMU/vDEVICE) | > > | _____________ _____________ | > > | | | | | | > > | |----------------| vIOMMU |<---| vDEVICE |<------| | > > | | | | |_____________| | | > > | | ______ | | _____________ ___|____ | > > | | | | | | | | | | | > > | | | IOAS |<---|(HWPT_PAGING)|<---| HWPT_NESTED |<--| DEVICE | | > > | | |______| |_____________| |_____________| |________| | > > |______|________|______________|__________________|_______________|_____| > > | | | | | > > ______v_____ | ______v_____ ______v_____ ___v__ > > | struct | | PFN | (paging) | | (nested) | |struct| > > |iommu_device| |------>|iommu_domain|<----|iommu_domain|<----|device| > > |____________| storage|____________| |____________| |______| > > > > This vDEVICE object is used to collect and store all vIOMMU-related device > > information/attributes in a VM. As an initial series for vDEVICE, add only > > the virt_id to the vDEVICE, which is a vIOMMU specific device ID in a VM: > > e.g. vSID of ARM SMMUv3, vDeviceID of AMD IOMMU, and vID of Intel VT-d to > > a Context Table. This virt_id helps IOMMU drivers to link the vID to a pID > > of the device against the physical IOMMU instance. This is essential for a > > vIOMMU-based invalidation, where the request contains a device's vID for a > > device cache flush, e.g. ATC invalidation. > > > > Therefore, with this vDEVICE object, support a vIOMMU-based invalidation, > > by reusing IOMMUFD_CMD_HWPT_INVALIDATE for a vIOMMU object to flush cache > > with a given driver data. > > > > As for the implementation of the series, add driver support in ARM SMMUv3 > > for a real world use case. > > > > This series is on Github: > > https://github.com/nicolinc/iommufd/commits/iommufd_viommu_p2-v4 > > > > For testing, try this "with-rmr" branch: > > https://github.com/nicolinc/iommufd/commits/iommufd_viommu_p2-v4-with-rmr > > Is there any real example of a .vdevice_alloc hook, besides the > selftests? It is not in iommufd_viommu_p2-v4-with-rmr, hence the > question. I am trying to sketch something with this new machinery and > less guessing would be nice. Thanks, No, I am actually dropping that one, and moving the vdevice struct to the private header, as there seems to be no use case: https://lore.kernel.org/linux-iommu/ZxsSYbK3gqyC84U7@Asurada-Nvidia/ https://lore.kernel.org/linux-iommu/ZxsTAANTTuQzQ9HR@Asurada-Nvidia/ Do you need vdevice_alloc in the driver for your sketch? Thanks Nicolin
