virtio-snd: implement queue function lookup table

[Cuda-Chen]

Introduce a function lookup table to handle virtio-snd queues. This
prepares the device for upcoming PCM I/O receive and event features
by allowing queue ID indexing for callbacks.

• Set unimplemented PCM I/O receive and event entries to trigger a
  failed null check.
• Set control and event queue flush entries to trigger a failed null
  check as flushing is not required for these queues.

---

Summary by cubic

Added a queue operation lookup table for virtio-snd. Notify events now use the queue ID with an optional flush flag to select handlers, paving the way for PCM RX and event support.

• Refactors

  • Centralized virtio_queue_notify_handler to index handlers; removed the callback parameter.
  • Replaced macro-generated TX handlers with a shared body and two explicit handlers (normal, flush).
  • Uses index & 0x03 for queue selection; operations picked from a small table (0–3 normal, 4–7 flush).

• New Features

  • Flush routing via bit 0x04 in the index.
  • RX and event ops set to NULL to trigger a failed null check until implemented.
  • Control and event flush entries set to NULL to trigger a failed null check (flushing not required).

^{Written for commit 7afe818. Summary will update on new commits.}

[cubic-dev-ai]

3 issues found across 1 file

Prompt for AI agents (all issues)

Check if these issues are valid — if so, understand the root cause of each and fix them.


<file name="virtio-snd.c">

<violation number="1" location="virtio-snd.c:935">
P3: Typo in comment: &#39;opration&#39; should be &#39;operation&#39;.</violation>

<violation number="2" location="virtio-snd.c:949">
P3: Typos in comment: &#39;whcih&#39; should be &#39;which&#39; and &#39;net&#39; should be &#39;not&#39;.</violation>

<violation number="3" location="virtio-snd.c:1026">
P1: Potential out-of-bounds array access: `index` is masked with `&amp; 0x03` for queue selection but used directly for table lookup. If `index &gt;= 8`, this causes undefined behavior. Consider adding bounds checking: `__virtio_snd_queue_op_tbl[index &amp; 0x07]` to match the design pattern.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

1 issue found across 1 file

Prompt for AI agents (all issues)

Check if these issues are valid — if so, understand the root cause of each and fix them.


<file name="virtio-snd.c">

<violation number="1" location="virtio-snd.c:1014">
P1: Potential NULL pointer dereference: the lookup table contains NULL entries but there&#39;s no NULL check before calling the function pointer. If `index &amp; 0x07` evaluates to 1, 3, 4, 5, or 7, this will crash. The comment about &#39;trigger a compilation error&#39; is incorrect - NULL entries compile fine but crash at runtime.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[jserv]

Thank @Cuda-Chen for contributing!