Robert Allan James
dc2f38a1e1
Root cause of the G.1 follow-up boot-time attach race: on pathological controller behavior the xhci_poll_events() drain loop had no hard ceiling. ERDP is written back only when the loop exits, so the controller cannot reclaim event TRBs mid-drain; if it keeps producing events the head can chase the software dequeue pointer forever. xhci_poll_events() never returns, sk_repl_idle() never reaches its bot_msc_attach_pending check, and a fresh USB BOT device that finished SET_CONFIGURATION is left flagged-but-never- attached while the guest appears hung. Fix: bound the drain to a full ring (XHCI_EVT_RING_MAX_DRAIN = 256), so xhci_poll_events() always terminates and always writes ERDP each call. Unprocessed events keep their cycle bit and are re-read next poll; nothing is dropped. On the healthy path one drain processes only the one-or-few events the controller posts per chained command, so the bound never triggers except in the pathological case it breaks. Beyond the G.1 additions: a new macro in include/starkernel/xhci.h and a bounded loop in src/starkernel/usb/xhci.c. Builds clean on amd64. Verified across six consecutive fresh QEMU boots (previously intermittently hung).
capsules/
FORTH personality files loaded by the VM at boot. A capsule is an immutable, content-addressed payload; its XXHash64 hash is its identity. Any mutation changes the hash and the birth protocol rejects the image.
Key files
| File | Type | Purpose |
|---|---|---|
init.4th |
(m) MAMA_INIT |
Default Mama VM personality — loaded at LBN 2048 |
ACL.4th |
user | Word-level ACL system; self-activating at boot |
zuse.4th |
user | Bootstrap superuser; loaded by ACL.4th |
doe.4th |
user | DoE workload words (EXEC-DOE) — opt-in |
init-0.4th … init-9.4th |
(p) |
Numbered personality variants |
init-l8-*.4th |
(p) |
L8 Jacquard mode variants (stable/volatile/diverse/temporal/transition/omni) |
hermes/init.4th |
(p) |
Hermes baby VM personality |
artemis/init.4th |
(p) |
Artemis baby VM personality |
Block namespace
Block ranges are shared across all loaded capsules — collisions cause silent word-definition overwrites.
| Range | Owner |
|---|---|
| 2048–2099 | init.4th |
| 2100–2199 | doe.4th |
| 3000–3999 | workload capsules |
| 4000+ | user-defined (ACL.4th, zuse.4th, …) |
Each block is limited to 1024 bytes. Verify with wc -c before committing.
See also
experiments/bare_metal/README.md— DoE protocols and block namespace rulesdocs/03-architecture/word-acl/DESIGN.md— ACL system designtools/mkcapsule.c— assembles capsules intocapsule_generated.c- Project root