VFIO PCI variant driver for Virtio VFs (virtio-net and virtio-block)
A specialised passthrough driver that lets hypervisors hand virtio-net and virtio-block PCIe virtual functions directly to guest VMs while still supporting features like legacy I/O access and live migration. It is used mainly with NVIDIA BlueField DPUs and similar SmartNIC hardware that exposes virtio devices via SR-IOV, and it underpins live-migration of those VFs between hosts.
recommendation
It should stay because the code is actively maintained and growing: introduced in late 2023 for virtio-net VFs, extended in early 2025 to cover virtio-block live migration, and updated again in late 2025 alongside broader VFIO API work. NVIDIA's current BlueField documentation shows it is the supported path for assigning virtio VFs to VMs and migrating them, so while overall deployment is niche, the hardware is still being sold and the driver is clearly not obsolete.
repository signals
sources
- lore.kernel.org
Initial upstream series introduced this driver for virtio-net VFs, exposing legacy I/O via VFIO rather than removing legacy-only functionality.
- lore.kernel.org
Upstream expanded the driver in 2025 to support virtio-block live migration, showing feature growth rather than obsolescence.
- lore.kernel.org
The driver received substantive VFIO API maintenance in late 2025 as part of active subsystem work.
- docs.nvidia.com
Current vendor documentation describes live migration using Virtio VF PCIe devices and VFIO on BlueField-era deployments.
- docs.nvidia.com
Current vendor deployment documentation shows SR-IOV virtio-net PF/VF provisioning and assignment of virtio VFs to VMs, indicating ongoing real-world deployment.
codex reasoning notes (technical)
Real driver confirmed locally via shell (`rg`, `sed`) in Kconfig/main.c: PCI driver with module_pci_driver() for virtio-net/block VFs. Lore evidence came from local `git -c safe.directory=... log -- drivers/vfio/pci/virtio`, which exposed canonical lore Link URLs for 2023 introduction, 2025 virtio-block enablement, and 2025 VFIO API conversion. Deployment evidence came from `web.search_query` to NVIDIA docs showing current BlueField virtio-net/VF live-migration and SR-IOV VF deployment guidance. Additional `web.search_query` against lore for removal/deprecate terms returned no hits; combined with substantive 2025 maintenance, that argues against deprecation. This is niche virtualization infrastructure, so deployments are low rather than medium/high, but it is clearly not obsolete.