Some old and unmaintained drivers for Linux’s Virtual Function I/O (VFIO) support are being marked as deprecated for eventual removal, including the generic VFIO platform driver.
Red Hat engineer Alex Williamson who is the upstream maintainer of VFIO support and related pieces of the Linux virtualization stack has posted the patches to begin deprecating some unmaintained code. He explained in the patch series last week:
“The vfio-fsl-mc driver has been orphaned since April 2024 after the maintainer became unresponsive. More than a year later, the driver has only received community maintenance. Let’s take the next step towards removal by marking it obsolete/deprecated.
The vfio-platform and vfio-amba drivers have an active maintainer, but even the maintainer has no ability to test these drivers anymore. The hardware itself has become obsolete and despite Eric’s efforts to add support for new devices and presenting on the complexities of trying to manage and support shared resources at KVM Forum 2024, the state of the driver and ability to test it upstream has not advanced. The experiment has been useful, but seems to be reaching a conclusion. QEMU intends to remove vfio-platform support in the 10.2 release. Mark these drivers as obsolete/deprecated in the kernel as well.”
The VFIO platform driver is for generic VFIO handling for any platform device. The vfio_fsl_mc driver is for VFIO on QorIQ DPAA2 fsl-mc bus devices. The VFIO AMBA driver is for ARM AMBA devices and also deprecated is the Calxeda XGMAC reset supportm AMD XGBE reset support for their Seattle developer board, and the BCMFLEXRM reset drriver for Broadcom FlexRM reset.
There is this YouTube presentation recording from KVM Forum 2024 that goes into more detail over the planned deprecation/removal of VFIO-Platform and related unmaintained code.
Since last week no one has stepped up to maintain the code or object to its obsolete/deprecation notice so will likely be submitted as part of the next kernel cycle and then presumably its removal next year.
