Replaces the "Synthesized empty file" stub for cache:/* paths with a
real host-FS HostPathDevice-style mount. Each KernelState gets a fresh
per-process tmpdir under /tmp/xenia-rs-cache-<pid>-<id>/ which is
cleared on init for lockstep determinism (mirrors canary's
xenia_main.cc:649 RegisterSymbolicLink("cache:", "\\CACHE") +
HostPathDevice in xenia-canary/src/xenia/vfs/devices/host_path_device.cc).
NtCreateFile now honours create_disposition for cache: paths:
FILE_OPEN -> NOT_FOUND if missing
FILE_CREATE -> NAME_COLLISION if present
FILE_OPEN_IF -> open or create
FILE_OVERWRITE_IF -> create or truncate
FILE_OVERWRITE -> NOT_FOUND if missing, else truncate
FILE_SUPERSEDE -> create or truncate
NtReadFile / NtWriteFile / NtSetInformationFile (XFileEndOfFileInformation)
/ NtQueryInformationFile / NtQueryFullAttributesFile route through
std::fs against the per-handle host_path; non-cache paths keep their
legacy semantics (read-only disc image, synth-empty stubs).
Verified by audit-037 cascade:
- sub_82459D18 (cache-miss restore): 0 fires (was firing constantly)
- sub_8245D230 (resize/zero-fill): 0 fires (was firing constantly)
- 105+ real cache-file writes per 500M run; 4+ MB of game data persisting
to disk per boot; cache:/recent, cache:/access, cache:/d4ea*.tmp, etc.
- Lockstep deterministic at instructions=100000004 / imports=987485
across 3+ reruns (digest shifted as expected; goldens re-baselined).
- swaps=2 plateau still in place; cluster L1 unactivated. Cascade
dimension D (cluster activation) — UNKNOWN, no L1 fires.
Tests 640 -> 645 (+5 cache-specific unit tests; full workspace green).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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