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kubevirtci: Add fake SR-IOV vGPU kernel module for testing - #16717

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oshoval:fake-sriov-vgpu-driver
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kubevirtci: Add fake SR-IOV vGPU kernel module for testing#16717
oshoval wants to merge 1 commit into
kubevirt:mainfrom
oshoval:fake-sriov-vgpu-driver

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@oshoval

@oshoval oshoval commented Feb 2, 2026 •
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What this PR does

Add a kernel module that creates fake PCI devices in /sys/bus/pci/devices/ to simulate NVIDIA SR-IOV Virtual Functions with vGPU profiles assigned.

This enables testing of PR #16710's vGPU VF discovery logic without requiring real GPU hardware. The module:
Note: didn't test e2d, just device creation.

  • Creates a virtual PCI bus at domain 0001
  • Registers fake PCI devices with NVIDIA Tesla T4 vendor/device IDs
  • Provides nvidia/current_vgpu_type sysfs attribute for vGPU profile detection
  • Devices appear as real PCI devices visible to virt-handler

Usage:
cd kubevirtci/cluster-up/cluster/kind-1.33-vgpu/fake-sriov-vgpu make # or use container build sudo ./setup-fake-sriov.sh setup

Devices will appear at /sys/bus/pci/devices/0001:00:XX.X with:

  • vendor: 0x10de (NVIDIA)
  • device: 0x1eb8 (Tesla T4)
  • nvidia/current_vgpu_type: configurable vGPU profile

References

Why we need it and why it was done in this way

The following tradeoffs were made:

The following alternatives were considered:

Links to places where the discussion took place:

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@oshoval @cursoragent
kubevirtci: Add fake SR-IOV vGPU kernel module for testing
229cde7 
Add a kernel module that creates fake PCI devices in /sys/bus/pci/devices/
to simulate NVIDIA SR-IOV Virtual Functions with vGPU profiles assigned.

This enables testing of PR kubevirt#16710's vGPU VF discovery logic without
requiring real GPU hardware. The module:

- Creates a virtual PCI bus at domain 0001
- Registers fake PCI devices with NVIDIA Tesla T4 vendor/device IDs
- Provides nvidia/current_vgpu_type sysfs attribute for vGPU profile detection
- Devices appear as real PCI devices visible to virt-handler

Usage:
  cd kubevirtci/cluster-up/cluster/kind-1.33-vgpu/fake-sriov-vgpu
  make  # or use container build
  sudo ./setup-fake-sriov.sh setup

Devices will appear at /sys/bus/pci/devices/0001:00:XX.X with:
- vendor: 0x10de (NVIDIA)
- device: 0x1eb8 (Tesla T4)
- nvidia/current_vgpu_type: configurable vGPU profile

Signed-off-by: oshoval <[email protected]>
Co-authored-by: Cursor <[email protected]>
@kubevirt-bot

kubevirt-bot commented Feb 2, 2026

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Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

@kubevirt-bot kubevirt-bot added do-not-merge/work-in-progress Indicates that a PR should not merge because it is a work in progress. release-note-none Denotes a PR that doesn't merit a release note. dco-signoff: yes Indicates the PR's author has DCO signed all their commits. sig/buildsystem Denotes an issue or PR that relates to changes in the build system. size/XXL labels Feb 2, 2026
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kubevirt-bot commented Feb 2, 2026

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[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
Once this PR has been reviewed and has the lgtm label, please assign brianmcarey for approval. For more information see the Code Review Process.

The full list of commands accepted by this bot can be found here.

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@oshoval

oshoval commented Feb 2, 2026

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$ sudo ./setup-fake-sriov.sh setup
[INFO] Loading fake-sriov-vgpu module...
[INFO] Module loaded successfully
[INFO] Creating 4 fake VF devices...
[INFO] Created VF: slot=0 func=0 (vgpu_type=256)
[INFO] Created VF: slot=1 func=0 (vgpu_type=256)
[INFO] Created VF: slot=2 func=0 (vgpu_type=256)
[INFO] Created VF: slot=3 func=0 (vgpu_type=256)
[INFO] Created 4 VF devices

[INFO] === Fake SR-IOV vGPU Status ===

Loaded modules:
fake_sriov_vgpu        24576  0

Created VFs:
0001:00:00.0 vgpu_type=256
0001:00:01.0 vgpu_type=256
0001:00:02.0 vgpu_type=256
0001:00:03.0 vgpu_type=256

PCI devices (fake domain 0001):
lrwxrwxrwx. 1 root root 0 Feb  2 10:15 0001:00:00.0 -> ../../../devices/pci0001:00/0001:00:00.0
lrwxrwxrwx. 1 root root 0 Feb  2 10:15 0001:00:01.0 -> ../../../devices/pci0001:00/0001:00:01.0
lrwxrwxrwx. 1 root root 0 Feb  2 10:15 0001:00:02.0 -> ../../../devices/pci0001:00/0001:00:02.0
lrwxrwxrwx. 1 root root 0 Feb  2 10:15 0001:00:03.0 -> ../../../devices/pci0001:00/0001:00:03.0

Example VF: /sys/bus/pci/devices/0001:00:00.0
  vendor: 0x10de
  device: 0x1eb8
  nvidia/current_vgpu_type: 256

@kubevirt-bot

kubevirt-bot commented Feb 18, 2026

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@oshoval: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name Commit Details Required Rerun command
pull-kubevirt-e2e-k8s-1.35-sig-compute-migrations 229cde7 link true /test pull-kubevirt-e2e-k8s-1.35-sig-compute-migrations
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@oshoval

oshoval commented Apr 29, 2026 •
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closing for now,
since there arent enough reviewers + need to be brave to use the kernel module,
it is off the table atm

will be glad if desired to open it in the future

@oshoval oshoval closed this Apr 29, 2026
@lexfrei lexfrei mentioned this pull request May 12, 2026
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@dollierp dollierp mentioned this pull request Jul 29, 2026
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