ef93a4fa14
Source changes (dormant parity infra, retained from iterate 2.AI/2.AO): - xenia-kernel/exports.rs: nt_create_event manual_reset polarity + related event wiring - xenia-gpu/mmio_region.rs: D1MODE_VBLANK_VLINE_STATUS hardcode parity Also lands the audit-runs/ analysis notes (.md/.txt/.json digests) for the iterate 2.x VSync/0x10e8/0x1004 wedge investigation. Raw trace dumps (.jsonl/.gz/.csv/.stdout) and agent worktrees (.claude/) are gitignored as regenerable local artifacts — see memory + HANDOFF for the running findings. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
128 lines
4.5 KiB
Markdown
128 lines
4.5 KiB
Markdown
# Phase Host-Audio-Eager — Re-validation (2026-05-19)
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## Progression metric (primary gate)
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| metric | pre-fix baseline | post-fix | delta |
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|-------:|:----------------:|:--------:|:-----:|
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| **swaps** | 1 | **1** | **0** |
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| **draws** | 0 | **0** | **0** |
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**The progression metric did NOT move.** Despite landing the eager-seed
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implementation cleanly with 3× reproducibility, neither swaps nor draws
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advanced. This matches the prior agent's diagnosis: the audio worker
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ordering issue is real, but the deeper root cause is voice-struct state
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divergence — the audio callback at `0x824D6640` in ours blocks on
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`KeWaitForMultipleObjects([0x82928B04, 0x82928AE0])` immediately
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because the voice struct at `[r31+356]` reads `0x01` (ours) vs `0x00`
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(canary). Pre-seeding 8 fires lets `try_inject_audio_callback` deliver
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the first callback earlier, but the callback still blocks on the same
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guest dispatchers — fires 2-8 sit in the queue because
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`interrupts.is_in_callback()` stays true.
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## 3× determinism
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```
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73e99d60029128b4d5c3dd98e540457d82a52b8a962e7495132be2be31411aca /tmp/digest_eager_1.json
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73e99d60029128b4d5c3dd98e540457d82a52b8a962e7495132be2be31411aca /tmp/digest_eager_2.json
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73e99d60029128b4d5c3dd98e540457d82a52b8a962e7495132be2be31411aca /tmp/digest_eager_3.json
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```
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All three cold runs produce byte-identical digest JSON. The
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seed-at-register implementation is fully deterministic in lockstep
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mode (the ticker accumulator gets pre-populated synchronously inside
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the register handler, no host-thread non-determinism).
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## Digest JSON
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```json
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{
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"instructions": 50000007,
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"imports": 40390,
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"unimpl": 0,
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"draws": 0,
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"swaps": 1,
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"unique_render_targets": 0,
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"shader_blobs_live": 0,
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"texture_cache_entries": 0
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}
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```
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`imports`/`unimpl` unchanged from the C+22 baseline (40390/0).
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## Phase B invariant
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```
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image_loaded_sha256 = ea8d160e9369328a5b922258a92113efb8d7ce3e1a5c12cc521e375985c91c18
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```
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UNCHANGED — Phase B is not affected by audio-runtime changes.
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## Per-chain matched-prefix
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100M-instruction cold trace vs canary baseline
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(`xenia-rs/audit-runs/phase-d-stage1/canary-cvaroff-trunc.jsonl` —
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pre Phase D D-extension absorber, so main reads at the C+18
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102,424 value, NOT the post-D-extension 105,046).
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| chain | pre-fix | post-fix | delta | first divergence |
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|------:|--------:|---------:|------:|:-----------------|
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| canary tid=4 → ours tid=11 | 11 | **11** | 0 | (preserved) |
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| canary tid=6 → ours tid=1 | 102,424 | **102,424** | **0** | `NtQueryFullAttributesFile` (C+18-era) |
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| canary tid=7 → ours tid=2 | 32 | **32** | 0 | (preserved) |
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| canary tid=12 → ours tid=7 | 4 | **4** | 0 | C+23 idx=4 |
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| canary tid=14 → ours tid=9 | 41 | **41** | 0 | (no advance — primary target) |
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| canary tid=15 → ours tid=10 | 16 | **16** | 0 | (no advance — primary target) |
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The two primary targets (tid=14→9 and tid=15→10) were the audio worker
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guest threads spinning on the uninitialized voice struct. Their
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matched-prefix did NOT advance.
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## Kernel tests
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- Pre: 217 passed
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- Post: **221 passed** (+4 new `seed_fires_for_*` tests)
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- Failures: 0
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- All existing tests pass
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## Build
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`cargo build --release` clean. One pre-existing dead-code warning
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unrelated to this fix.
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## Total LOC
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| file | added | removed |
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|------|------:|--------:|
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| `crates/xenia-kernel/src/xaudio.rs` | 86 | 0 |
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| `crates/xenia-kernel/src/exports.rs` | 18 | 5 |
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| **total** | **104** | **5** |
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Net ~100 LOC, of which ~60 LOC are tests + doc comments. Engine logic
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delta is ~25 LOC.
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## Conclusion
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The implementation lands cleanly:
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- 3× cold-deterministic
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- Phase B unchanged
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- All tests pass
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- Sister chains preserved
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But the progression metric (swaps/draws) did NOT move. This is an
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HONEST NEGATIVE RESULT: the eager-seed approach addresses the symptom
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(ticker delays the first callback) but not the root cause (the
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callback at 0x824D6640 still blocks on guest dispatchers that only
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tid=9/10 can signal, and tid=9/10 are stuck on a voice-struct field
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that the callback would need to clear — but doesn't, because canary's
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callback takes a DIFFERENT control-flow path that doesn't reach the
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KeWaitForMultipleObjects in the first place).
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The deeper fix requires either:
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- Identifying the guest write that initializes `[r31+356]` to 0 in
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canary's boot path and ensuring ours produces the same write.
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- A true host-side audio worker thread that can run the callback
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in a host context (substantial threading-model rework).
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Both are out of scope for this session per the brief's "Don't widen
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scope" tripstone.
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