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LithosAnanke/src/starkernel
Robert Allan JamesandClaude Sonnet 5 b301317902
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xHCI: drive Port Reset on port reuse; WIREBIND: kill the console VM too (FABRIC-3.md §XI.5)
Two independent bugs that together caused a reliable hotplug wedge:
reusing an xHCI port for a second identity right after an unclean
detach of a first would leave no further hotplug events reaching the
guest at all.

Bug 1 (xhci.c/xhci_driver.h): the xHCI driver never drove PORTSC.PR --
a known, named gap since Milestone 2e (the code's own comment flagged
it, PORTSC_PR/PRC were defined but never referenced). A port's first
connect each boot reads PED already set, so skipping the reset
happened to work; a second device on the same port after a prior
disconnect reads PED clear, and Address Device reliably failed without
an explicit reset cycle. New XHCI_CONN_AWAIT_PORT_RESET state drives
PR and waits for PED to read set before proceeding to Enable Slot.

Bug 2 (capsule_wirebind.c): capsule_wirebind_eject()/unclean_detach()
compared g_repl_active_vm against the *user* VM's pointer
(g_wirebind_attached_vm_id tracks that one, not the console VM) --
never equal, since USE/g_repl_active_vm always points at the console
VM. The guard never fired and the console VM was never killed at all,
only orphaned -- paired to a dead user VM but still the REPL's active
session. New wirebind_teardown_console() helper resolves and tears
down the console VM by its own tracked bare username.

Verified live on amd64: the exact repro (identity 01 on port 2,
unclean detach, identity 02 on the same port immediately after) --
previously wedged with "xhci: address device failed" and no further
hotplug activity; now attaches cleanly and fast, both VMs' KILL
messages appear, console is immediately interactive on the new
identity. Three-arch clean qemu acceptance passed, all clean on the
first attempt.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014Ec88YKxxhZGG1RNnune78
2026-09-09 22:11:09 -04:00
..
2026-09-01 12:07:32 -04:00

src/starkernel/

LithosAnanke — the bare-metal UEFI kernel that boots StarForth directly on hardware (amd64/aarch64/riscv64). Built only via Makefile.starkernel; the only valid acceptance test is the three-arch QEMU boot (see .claude/CLAUDE.md), never make test.

  • kernel_main.c — kernel entry point, driving the boot milestones (console init, PMM, VMM, interrupts, timers, kmalloc heap, VM bootstrap).
  • repl.c — kernel REPL.
  • doe_log.c — kernel-side DoE (Design of Experiments) metrics logging.

Subdirectories:

  • arch/{amd64,aarch64,riscv64}/ — per-architecture support (APIC/GIC/ PLIC interrupt controller, timers, boot/ISR assembly).
  • boot/ — UEFI loader, ELF loading, kernel command-line parsing.
  • capsule/ — capsule birth/run/load/validate pipeline.
  • hal/ — hardware-abstraction-layer implementation (console, framebuffer, VT100, memory, host services).
  • hash/ — XXHash64 content-addressing implementation.
  • math/ — kernel-build Q48.16 fixed-point arithmetic.
  • memory/ — physical/virtual memory managers and the kernel heap.
  • pci/ — PCI bus enumeration.
  • virtio/ — VirtIO block device driver.
  • vm/ — kernel VM subsystem (bootstrap, core interpreter, parity logging, capsule arena).

See include/starkernel/README.md for the corresponding headers.