vGPU Device Manager: no SR-IOV / vendor-specific VFIO vGPU creation on Ada Lovelace / Hopper (mdev-only)

[lexfrei]

Summary

The vGPU Device Manager (nvidia-vgpu-device-manager) is built around the legacy mediated-device (mdev) framework only. On Ada Lovelace and newer GPUs (L40/L40S, RTX Ada, H100, H200, Blackwell) running the vGPU release 17/18+ host driver, the driver no longer exposes mdev — vGPU profiles are assigned per SR-IOV Virtual Function through the vendor-specific VFIO sysfs (/sys/bus/pci/devices/<VF>/nvidia/current_vgpu_type). As a result the GPU Operator has no way to create SR-IOV vGPU devices on these GPUs.

Environment

• GPU: NVIDIA H200 SXM 141GB (10de:2335)
• Host vGPU driver: 580.159.01 (NVIDIA vGPU release 18, -vgpu-kvm)
• Kernel: 6.8
• GPU Operator in sandbox mode: sandboxWorkloads.enabled=true, node label nvidia.com/gpu.workload.config=vm-vgpu
• vgpu-device-manager image v0.4.2

Problem

On this GPU /sys/bus/mdev/ does not exist by design — the driver uses the vendor-specific VFIO framework (nvidia-smi -q reports Host VGPU Mode : SR-IOV). vGPU is configured per VF: after /usr/lib/nvidia/sriov-manage -e <BDF>, each VF exposes /sys/bus/pci/devices/<VF>/nvidia/{creatable_vgpu_types, current_vgpu_type, gpu_instance_id, placement_id, ...}, and a vGPU is created by writing a type id to current_vgpu_type. There is no mdev bus for the device manager to walk, so it cannot enumerate or create vGPU devices — matching the failure reported in #591:

error getting vGPU config: error getting all vGPU devices: unable to read MDEV devices directory: open /sys/bus/mdev/devices: no such file or directory

With a host-installed driver the vgpu-device-manager init container instead blocks indefinitely on waiting for NVIDIA vGPU Manager to be setup. Either way there is no operator path to create SR-IOV vGPUs on Ada/Hopper.

The rest of the stack is ready — only operator-side creation is missing

• KubeVirt consumes these VFs. Its PCI device plugin recognizes a VF bound to the nvidia driver once current_vgpu_type != 0 and advertises it — vGPU: SRIOV support kubevirt/kubevirt#16890 (merged 2026-04-14), available in KubeVirt v1.9 (v1.9.0-beta.0; the added file pkg/virt-handler/device-manager/nvidia.go is present in v1.9.0-beta.0 but not in the v1.8.x releases / release-1.8). The design discussion in Support NVIDIA vGPU "vendor-specific VFIO framework" (SR-IOV vGPU on Ada Lovelace, Hopper, kernel 6.8+) kubevirt/kubevirt#17642 explicitly scopes vGPU profile assignment (current_vgpu_type) as a node-level concern for gpu-operator or a custom DaemonSet — i.e. exactly what this issue asks the operator to do.
• Manual creation works: sriov-manage -e + echo <type-id> > .../nvidia/current_vgpu_type yields a working, KubeVirt-consumable vGPU (validated on H200 with a whole-card profile).
• Rebinding VFs to vfio-pci is not a workaround — unbinding the VF resets current_vgpu_type to 0.

Request

Add support in vgpu-device-manager (or a dedicated component) for the vendor-specific VFIO / SR-IOV per-VF model (current_vgpu_type), so vGPU devices are declaratively created on Ada Lovelace / Hopper / Blackwell, analogous to what already works for mdev GPUs today. The downstream discovery/advertisement side is already handled by KubeVirt.

References

• error getting vGPU config: error getting all vGPU devices: unable to read MDEV devices directory: open /sys/bus/mdev/devices: no such file or directory #591 — mdev-era predecessor (2023, closed as stale); the underlying gap persists for current SR-IOV vGPU hardware.
• Support NVIDIA vGPU "vendor-specific VFIO framework" (SR-IOV vGPU on Ada Lovelace, Hopper, kernel 6.8+) kubevirt/kubevirt#17642, vGPU: SRIOV support kubevirt/kubevirt#16890 — KubeVirt-side support for the vendor-specific VFIO framework (implemented).
• Same gap tracked elsewhere: Add support for NVIDIA vGPU vendor-specific VFIO framework OpenNebula/one#6841, [BUG] vGPU SR-IOV not getting visible on nvidea l40S harvester/harvester#6487, NVIDIA vGPU fails guest driver installation cloud-hypervisor/cloud-hypervisor#7572.