hotplug_gpu: updated since hotunplug is not supported for NVIDIA GPUs

[rh-jugraham]

Summary by CodeRabbit

• Tests

  • Simplified GPU hotplug test flow by removing unsupported hot‑unplug steps, focusing on hotplug validation only.
  • Reduces flaky results and false failures with NVIDIA GPUs.

• Documentation

  • Clarified that hot‑unplug is not supported for NVIDIA GPUs.
  • Updated test logs/messages to reflect hotplug‑only behavior.

[coderabbitai]

Walkthrough

Removed NVIDIA GPU hot-unplug/replug validation from the hotplug GPU test. The test now performs hotplug, driver validation, and final exclusivity checks only. Documentation/log text updated to reflect lack of hot-unplug support. Unused import removed.

Changes

Cohort / File(s)	Summary of Changes
GPU hotplug test simplification libvirt/tests/src/gpu/hotplug_gpu.py	Removed unplug/replug workflow and related GPU state checks; retained hotplug, driver validation, and exclusivity check. Updated logs/docs to state NVIDIA hot-unplug not supported. Cleaned imports (removed vm_xml).

Sequence Diagram(s)

sequenceDiagram
  autonumber
  participant T as Test Runner
  participant L as libvirt/Host
  participant G as Guest VM
  participant D as NVIDIA Driver

  rect rgb(235, 245, 255)
  note over T,L: Current flow (hotplug-only)
  T->>L: Attach GPU (hostdev) to VM
  L-->>G: Device appears in guest
  T->>G: Validate via nvidia-smi / driver presence
  T->>L: Final exclusivity check
  end

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sequenceDiagram
  autonumber
  participant T as Test Runner
  participant L as libvirt/Host
  participant G as Guest VM
  participant D as NVIDIA Driver

  rect rgb(255, 240, 240)
  note over T,L: Removed flow (unplug/replug)
  T->>L: Detach GPU (hostdev) from VM
  L-->>G: Device removed event
  T-x G: (Removed) Validate device absence
  T-x L: (Removed) Re-attach GPU and re-validate
  end

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Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

I hop through logs with nimble cheer,
Hotplug stays, unplug’s not here.
GPUs snug in virtual dens,
Drivers nod with tidy grins.
Imports trimmed, the path is clean—
Thump-thump! a lean and focused scene.
Carrot commits: crisp and keen.

Pre-merge checks and finishing touches

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title Check	✅ Passed	The title directly references the primary change, namely updating the hotplug_gpu test due to unsupported hot-unplug support for NVIDIA GPUs, which matches the removal of the unplug/replug workflow in the changeset.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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📜 Recent review details

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📥 Commits

Reviewing files that changed from the base of the PR and between 0ada0bf and 835a3e8.

📒 Files selected for processing (1)

• libvirt/tests/src/gpu/hotplug_gpu.py (1 hunks)

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (4)

• GitHub Check: Python 3.11
• GitHub Check: Python 3.9
• GitHub Check: Python 3.12
• GitHub Check: Python 3.8

🔇 Additional comments (2)

libvirt/tests/src/gpu/hotplug_gpu.py (2)

11-12: LGTM: Clear documentation of NVIDIA GPU limitation.

The updated docstring accurately reflects that hot-unplug is not supported for NVIDIA GPUs, properly setting expectations for the test scope.

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27-38: All hot-unplug code removed; only a docstring note remains
The only reference to “hotunplug” is the docstring in hotplug_gpu.py, which appropriately notes that hot-unplug isn’t supported. No further changes required.

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[Yingshun]

The device will be hotplugged in Line 29, these lines can be removed I think.

[Yingshun]

I would suggest keeping this check.