[feat] hma connector supports GPU buffer MR for GPUDirct RDMA

[relat-ivity]

Purpose

Enable the HMA connector to provide GPU KV buffer address and size metadata to UCM stores, following the existing ucm_connector registration logic in PR #958.

Modifications

• hma_connector.py: Collects GPU buffer addresses and sizes of the vLLM KV cache, and passes them to UCM store for GDR pre-registration.

Test

[ygwpz]

Follow-up Review - PR #981

Previous Concerns: All Addressed ✅

All 7 concerns from the previous review have been successfully addressed:

1. ✅ Data integrity assertion (Line 167-169): Added assert len(buffer_addrs) == len(buffer_sizes)
2. ✅ Code clarity (Line 29-30): Added comment explaining GPU buffer purpose
3. ✅ Debug logging (Line 119-125): Added logging for GPU buffer registration
4. ✅ Redundant int() conversion (Line 171): Simplified key creation
5. ✅ Type safety (Line 112-116): Added validation for non-empty lists
6. ✅ Overflow protection (Line 46): Changed to safe sum calculation
7. ✅ Warning for missing layouts (Line 159-163): Added logging instead of silent skip

New Observations (Minor - L3-L5)

Three minor suggestions for code quality improvements. See inline comments below.

Summary

The new commits thoroughly address all previous concerns with appropriate safeguards, logging, and validation. The implementation is now more robust and maintainable. Good work!

The three minor suggestions below are optional improvements that could be addressed in a follow-up PR if desired.