Claude review: gpu: nova-core: gsp: support large RPCs via continuation record

[Claude Code Review Bot <claude-review@example.com>]

Patch Review

This is the main patch. The design is solid:

1. `SplitState::new()` checks if splitting is needed and stages the payload into kernel-allocated buffers
2. `SplitCommand` wraps the original command with truncated payload for the first message
3. `ContinuationRecords` iterates over remaining payload chunks

A few observations:

**`ContinuationRecords` doesn't implement `Iterator`**: The `next()` method signature matches `Iterator` but it doesn't implement the trait. This is likely intentional since `Iterator` would require `&mut self` lifetime complications with the returned `ContinuationRecord<'_>` borrowing from `self`. The usage in `send_command` with `while let Some(...)` is fine. Consider a brief comment explaining this design choice.

**Missing `Tested-by` tag**: This is the only non-trivial patch without a `Tested-by: Zhi Wang` tag (patches 1-7 and 9 all have it). This may be intentional since the patch changed substantively in v4/v5.

**The `SplitState::MAX_FIRST_PAYLOAD` associated constant**:
```rust
const MAX_FIRST_PAYLOAD: usize = MAX_CMD_SIZE - size_of::<C::Command>();
```
This is defined as an associated constant on the generic `SplitState<C>`, which is elegant since it depends on `C::Command`. It's also exposed to tests in patch 9 via `SplitState::<TestPayload>::MAX_FIRST_PAYLOAD`, which is a nice pattern.

**Allocation strategy**: The staging buffer uses `KVVec::from_elem(0u8, ...)` which zero-initializes. The data is immediately overwritten by `init_variable_payload`, so `KVVec::with_capacity` + `resize` would save the zero-fill, but this is a minor optimization concern for a path that's only taken for large (>64KB) RPCs.

**`ContinuationRecord` uses `Command = ()`**: This means the GspMsgElement header is written but the command body is entirely variable-length payload. This matches the continuation record protocol where only the raw data matters.

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Generated by Claude Code Patch Reviewer