Hello, The VFIO object hierarchy has some constraints because each VFIO type has a dual nature: a VFIO nature for passthrough support and a bus nature (PCI, AP, CCW, Platform) for its initial presentation. It seemed the best approach made because multi-inheritance is not feasible with QOM and both aspect of the VFIO object, passthrough and bus, require state. A QOM interface in that case is not sufficient.
One aspect of passthrough is interaction with the IOMMU. IOMMUFD support was recently added and for this purpose, we introduced an IOMMU backend framework simply based on a VFIOIOMMUOps struct. We didn't want to use QOM again because it would have exposed the various lowlevel backend objects to the QEMU machine and human interface which felt unnecessary at the time. The changes of this series introduce a VFIO_IOMMU QOM interface and its VFIOIOMMUClass to replace the current VFIOIOMMUOps. This provides better code abstraction for the type1 and sPAPR IOMMU backends and allows us to improve the vfio_connect_container() implementation. Also, QOM interfaces are not exposed at the QEMU interface level. Most important, we can now avoid compiling the sPAPR IOMMU support on targets not needing it. This saves some text in QEMU. Applies on vfio-next. Thanks, C. Changes in v2: - Removed superfluous define and struct definitions - Improved comments and commit log - Removed NULL initialization of vioc - Removed class_size initialization Cédric Le Goater (10): vfio/spapr: Extend VFIOIOMMUOps with a release handler vfio/container: Introduce vfio_legacy_setup() for further cleanups vfio/container: Initialize VFIOIOMMUOps under vfio_init_container() vfio/container: Introduce a VFIOIOMMU QOM interface vfio/container: Introduce a VFIOIOMMU legacy QOM interface vfio/container: Intoduce a new VFIOIOMMUClass::setup handler vfio/spapr: Introduce a sPAPR VFIOIOMMU QOM interface vfio/iommufd: Introduce a VFIOIOMMU iommufd QOM interface vfio/spapr: Only compile sPAPR IOMMU support when needed vfio/iommufd: Remove CONFIG_IOMMUFD usage include/hw/vfio/vfio-common.h | 2 - include/hw/vfio/vfio-container-base.h | 27 ++++- hw/vfio/common.c | 11 +- hw/vfio/container-base.c | 12 ++- hw/vfio/container.c | 146 ++++++++++++++++---------- hw/vfio/iommufd.c | 35 ++++-- hw/vfio/pci.c | 2 +- hw/vfio/spapr.c | 60 ++++++----- hw/vfio/meson.build | 2 +- 9 files changed, 197 insertions(+), 100 deletions(-) -- 2.43.0
