VFIO platform and AMBA device passthrough
Kernel infrastructure that lets a host hand a memory-mapped ARM or ARM64 platform device (and, historically, ARM AMBA bus devices) directly to a virtual machine or userspace driver, instead of binding it to a normal in-kernel driver. It is the platform-bus counterpart to the better-known PCI passthrough path and is mainly used in embedded virtualization and specialized appliance setups.
recommendation
Worth keeping but documenting its niche because the generic VFIO platform code is still actively maintained — it received reviewed feature work as recently as November 2025 — and remains the standard way to hand ARM/ARM64 platform devices to virtual machines or userspace drivers. However, two pieces inside this tree, the AMBA bus glue (CONFIG_VFIO_AMBA) and the AMD XGBE reset helper, are now explicitly marked deprecated in mainline and are on track for eventual removal, so packagers should expect those sub-options to disappear while the core stays.
repository signals
sources
- lore.kernel.org
Core vfio/platform code was still receiving reviewed feature work in November 2025, indicating active upstream maintenance rather than abandonment.
- lore.kernel.org
A second November 2025 patch in the same series updated vfio/platform APIs, reinforcing that the generic platform VFIO path is still being evolved.
- docs.kernel.org
Kernel documentation describes VFIO as current infrastructure for VM device assignment and userspace drivers, which supports ongoing niche deployment of VFIO-backed devices.
- cateee.net
LKDDb shows CONFIG_VFIO_PLATFORM still present through 6.19 and 7.0-rc+HEAD as generic support for any platform device.
- cateee.net
LKDDb shows CONFIG_VFIO_AMBA is now marked DEPRECATED and slated for future removal.
- cateee.net
One reset helper under this subtree, CONFIG_VFIO_PLATFORM_AMDXGBE_RESET, is also marked DEPRECATED in recent kernels.
codex reasoning notes (technical)
MCP lore_activity on vfio_platform.c and vfio_platform_common.c showed active 2025 feature patches with review tags and no removal signal in the sampled core-file history. Local shell inspection of drivers/vfio/platform/Kconfig and reset/Kconfig showed only subparts are explicitly marked DEPRECATED: vfio-amba and reset helpers. Web search provided docs.kernel.org VFIO docs and cateee LKDDb pages confirming current presence of CONFIG_VFIO_PLATFORM and deprecation status of the AMBA/reset subdrivers. Result: keep the directory, but annotate/split around deprecated subcomponents rather than deprecating the active generic vfio-platform core.