Robert Allan JamesandClaude Sonnet 5
b9c540a78b
Chains off the device descriptor request via a new deferred-action mechanism on xhci_dev_t (next_action/next_action_slot_id/next_action_length): a short 9-byte Configuration descriptor read learns wTotalLength, then a full read retrieves Config+Interface+Endpoint descriptors, walked for the Interface descriptor to confirm bInterfaceClass/SubClass/Protocol == Mass Storage/ SCSI/Bulk-Only Transport. The deferral exists because ringing the next doorbell synchronously inside xhci_poll_events()'s event-processing loop -- before the current event's ERDP write -- hung the guest outright (confirmed live via checkpoint logging, amd64). Fixed by moving the actual control-transfer submission to a small dispatch at the end of xhci_poll_events(), after ERDP is updated. A debug hack that shipped mid-session (forcing a repeated 9-byte read instead of chaining into the real 44-byte length, to isolate whether the hang was doorbell-ordering or length-specific) has been reverted: restored the real length and re-verified live. The doorbell-ordering fix was the whole story -- the 44-byte read completes cleanly. Verified live via QMP hotplug, all three architectures, byte-identical results: wTotalLength=0x2c, bInterfaceClass=0x08, bInterfaceSubClass=0x06, bInterfaceProtocol=0x50 -- confirmed Mass Storage/SCSI/BOT. Disconnect confirmed clean on every arch, no wedge. FABRIC-2.md Section X Milestone 2f updated with the full writeup. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01QPfdtaXs9ay1nbwuMnrscu
disk/
QEMU disk images used for Artemis (block-storage VM) persistence testing.
Mounted via Makefile.starkernel's ARTDISK variable (default
disk/artemis.img) as a virtio-blk-pci device on all three
architectures' kernel QEMU boots — not scripts/rundisk.sh, which targets
a separate, currently-unused disks/ (plural) directory for the hosted
VM's --disk-img= flag instead.
artemis.img— standard Artemis persistence test disk. Reformatted 2026-08-02: this image had been stuck in a corrupted state (validLithosAnankemagic header, but data not matching whatART-READ-TESTexpects) since before this repo's own git history begins (git logshows it already broken at the initial commit, carried over from the pre-split monorepo). Chasing down the resulting persistentFAIL: persist-readtraced to the data, not the code — the write→reboot→read round trip works correctly on a fresh image (seeartemis-debug-roundtrip.imgbelow). Reformatted by blanking the file and letting a normal boot format+write-test it; verifiedPASS: persist-readon amd64, aarch64, and riscv64 against the same image afterward (cross-arch resume, matching the arch-neutral on-disk format.claude/ARTEMIS.mdspecifies).artemis-debug-roundtrip.img— round-trip regression fixture created during that investigation. Known-good: format → self-test → write-test → reboot → resume →PASS: persist-read, confirmed 3 times in a row. Keep this in a passing state; if a future change breaks it, that's a real regression, not a stale-fixture artifact likeartemis.imgwas.artemis-persist-test.img— persistence round-trip test image (pre-existing; history/state not re-verified during the above investigation).artemis-poison.img— a separate test image (exact scenario not documented elsewhere in the repo as of this writing; name suggests an adversarial/corruption test, not confirmed).artemis-unrecognized-test.img— exercisesART-HALT-UNRECOG(.claude/ARTEMIS.mdacceptance criterion #6). Regenerated 2026-08-02: the previous copy of this file had itself been silently reformatted by a since-fixed bug in the generic block subsystem (src/block_subsystem.c) — it carried a valid low-level'STFR'/v2 header despite being meant to represent foreign disk content, direct forensic evidence of the bug described in.claude/ARTEMIS.md's Build Status item 6. Regenerated as 30MB of a repeatingPOISON-UNRECOGNIZED-DISK-TEST-FIXTURE--NOT-BLANK-NOT-STFR-NOT-ARTEMIS--ASCII pattern — deliberately neither blank, nor the block subsystem's own'STFR'magic, nor Artemis's"ARTEMIS\0"marker. Verified on amd64 and riscv64 post-fix: boot correctly halts (ARTEMIS HALT: unrecognized disk content) and the file's sha256 is now byte-for-byte identical before and after boot. Keep this fixture in this poisoned state — if a future change makes its sha256 change across a boot, that is exactly the regression this fixture exists to catch.
Note on incidental header churn: artemis.img picks up a few changed
header bytes on every ordinary boot even though no user data changes —
blk_subsys_attach_device() always records a fresh mounted_time on a
successfully recognized disk, which gets flushed at shutdown. This is
expected bookkeeping, not a bug; revert it before committing rather than
carrying timestamp noise in git history.
usb-thumbdrive-test.img— 64MB raw image backing a QEMUusb-storagedevice attached to the xHCI controller's bus (xhci0.0) for Milestone 2e/ 2h hotplug testing, added 2026-08-22. Not yet formatted with any LithosAnanke/Artemis header — at this point in the driver's development it only needs to exist as a backing store for a live Port Status Change event; formatting comes onceblkio_usb.candblk_subsys_attach_device()wiring exist (Milestone 2h).
Convention, standing as of 2026-08-22: every virtual disk/thumb-drive image
used for testing — Artemis persistence disks above, and USB Mass Storage
backing images alike — lives in this directory and is a tracked, committed
file, never scratchpad. This was already artemis.img's convention;
usb-thumbdrive-test.img and any future USB test images follow the same
rule. Confirmed no .gitignore in this repo excludes disk/*.img.
These are regenerable QEMU raw disk images, not source — see
.claude/ARTEMIS.md for the storage model they exercise.