fix(nvlink): use GPU platform chassis serial when nvlink_info is unset.

[rtamma-nv]

This should help with auto population of nvlink_info for managed hosts that are missing that info.

Fall back to the first GPU platform_info chassis_serial from machine
topology when nvlink_info is missing or empty, so MNNVL-capable hosts
can still be grouped and have nvlink_info populated from NMX-C hello.

Related issues

#3481

Type of Change

• Add - New feature or capability
• Change - Changes in existing functionality
• Fix - Bug fixes
• Remove - Removed features or deprecated functionality
• Internal - Internal changes (refactoring, tests, docs, etc.)

Breaking Changes

• This PR contains breaking changes

Testing

• [ X] Unit tests added/updated
• Integration tests added/updated
• Manual testing performed
• No testing required (docs, internal refactor, etc.)

Additional Notes

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Enterprise

Run ID: dfb34f5c-aea9-4b0a-bd2b-eb7b4d5e4ac5

📥 Commits

Reviewing files that changed from the base of the PR and between 0e199a7 and d04a0c5.

📒 Files selected for processing (2)

• crates/api-model/src/hardware_info.rs
• crates/nvlink-manager/src/lib.rs

🚧 Files skipped from review as they are similar to previous changes (2)

• crates/api-model/src/hardware_info.rs
• crates/nvlink-manager/src/lib.rs

---

Summary by CodeRabbit

• Bug Fixes
  • Improved chassis identification by deriving a chassis serial from the first GPU’s platform information when the primary chassis serial is missing.
  • More reliably ignores blank/whitespace-only chassis serial values to improve hardware matching.
  • Enhances downstream endpoint resolution and partition monitoring by producing more accurate chassis-based snapshots when chassis data is incomplete.

Walkthrough

Changes

Chassis serial resolution

Layer / File(s)	Summary
GPU platform serial accessor crates/api-model/src/hardware_info.rs	Adds first_gpu_platform_chassis_serial(), updates GPU test helpers, and tests missing, blank, and populated serial handling.
Managed-host chassis grouping crates/nvlink-manager/src/lib.rs	Prefers a trimmed NMX-C chassis serial and falls back to the first GPU platform serial during managed-host aggregation.

Estimated code review effort: 2 (Simple) | ~10 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the main change: falling back to GPU platform chassis serial when nvlink_info is unset.
Description check	✅ Passed	The description is clearly related to the implemented NVLink fallback behavior and updated tests.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@crates/api-model/src/hardware_info.rs`:
- Around line 967-977: Convert first_gpu_platform_chassis_serial into a
table-driven test using the established value_scenarios!/scenarios! helpers,
covering no GPUs, a GPU with missing platform_info, blank or whitespace-only
serials, and a valid serial; assert each scenario’s expected Option result and
remove the current imperative setup/assertions.

In `@crates/nvlink-manager/src/lib.rs`:
- Around line 78-93: Normalize the GPU-platform fallback in
managed_host_chassis_serial the same way as the nvlink_info chassis_serial path:
trim the value, discard it if empty, and only then return it as the grouping
key. Preserve the existing NMX-C-first fallback order and use
HardwareInfo::first_gpu_platform_chassis_serial as the fallback source.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Enterprise

Run ID: b416c2f8-3ae0-4689-ac59-e07b68ab5c73

📥 Commits

Reviewing files that changed from the base of the PR and between f5044bc and 0e199a7.

📒 Files selected for processing (2)

• crates/api-model/src/hardware_info.rs
• crates/nvlink-manager/src/lib.rs

[github-actions]

🔍 Container Scan Summary

Service	Total	Critical	High	Medium	Low	Other
boot-artifacts-aarch64	3	0	0	3	0	0
boot-artifacts-x86_64	3	0	0	3	0	0
forge-admin-cli-x86_64	259	13	30	78	7	131
machine-validation-runner	807	40	234	288	36	209
machine_validation	807	40	234	288	36	209
machine_validation-aarch64	807	40	234	288	36	209
nvmetal-carbide	807	40	234	288	36	209
TOTAL	3493	173	966	1236	151	967

Per-CVE detail lives in the per-service grype-* artifacts (JSON + SARIF). Severity counts only — no CVE IDs published here.