On Tue, Aug 27, 2024 at 12:51:30PM -0300, Jason Gunthorpe wrote: > This brings support for the IOMMFD ioctls: > > - IOMMU_GET_HW_INFO > - IOMMU_HWPT_ALLOC_NEST_PARENT > - IOMMU_DOMAIN_NESTED > - ops->enforce_cache_coherency() > > This is quite straightforward as the nested STE can just be built in the > special NESTED domain op and fed through the generic update machinery. > > The design allows the user provided STE fragment to control several > aspects of the translation, including putting the STE into a "virtual > bypass" or a aborting state. This duplicates functionality available by > other means, but it allows trivially preserving the VMID in the STE as we > eventually move towards the VIOMMU owning the VMID. > > Nesting support requires the system to either support S2FWB or the > stronger CANWBS ACPI flag. This is to ensure the VM cannot bypass the > cache and view incoherent data, currently VFIO lacks any cache flushing > that would make this safe. > > Yan has a series to add some of the needed infrastructure for VFIO cache > flushing here: > > https://lore.kernel.org/linux-iommu/20240507061802.20184-1-yan.y.zhao@xxxxxxxxx/ > > Which may someday allow relaxing this further. > > Remove VFIO_TYPE1_NESTING_IOMMU since it was never used and superseded by > this. > > This is the first series in what will be several to complete nesting > support. At least: > - IOMMU_RESV_SW_MSI related fixups > https://lore.kernel.org/linux-iommu/cover.1722644866.git.nicolinc@xxxxxxxxxx/ > - VIOMMU object support to allow ATS and CD invalidations > https://lore.kernel.org/linux-iommu/cover.1723061377.git.nicolinc@xxxxxxxxxx/ > - vCMDQ hypervisor support for direct invalidation queue assignment > https://lore.kernel.org/linux-iommu/cover.1712978212.git.nicolinc@xxxxxxxxxx/ > - KVM pinned VMID using VIOMMU for vBTM > https://lore.kernel.org/linux-iommu/20240208151837.35068-1-shameerali.kolothum.thodi@xxxxxxxxxx/ > - Cross instance S2 sharing > - Virtual Machine Structure using VIOMMU (for vMPAM?) > - Fault forwarding support through IOMMUFD's fault fd for vSVA > > The VIOMMU series is essential to allow the invalidations to be processed > for the CD as well. > > It is enough to allow qemu work to progress. > > This is on github: https://github.com/jgunthorpe/linux/commits/smmuv3_nesting > > v2: As mentioned above, the VIOMMU series would be required to test the entire nesting feature, which now has a v2 rebasing on this series. I tested it with a paring QEMU branch. Please refer to: https://lore.kernel.org/linux-iommu/cover.1724776335.git.nicolinc@xxxxxxxxxx/ Also, there is another new VIRQ series on top of the VIOMMU one and this nesting series. And I tested it too. Please refer to: https://lore.kernel.org/linux-iommu/cover.1724777091.git.nicolinc@xxxxxxxxxx/ With that, Tested-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
