sk_vm_switch_entry() stops being the Stage-2 placeholder bounce and becomes
every switch participant's own idle loop: it drains one of its own
kernel-Hermes messages per pass, on its own native stack (driven by the drain's
return value, so a non-consuming drain cannot spin), and when nothing is
drained it marks the VM parked_idle and yields back. It is entirely OS-driven,
with no VM-side yield word. sk_hermes_drain_checkpoint() gains a per-VM
hermes_draining guard so a payload's own in-word checkpoint cannot drain a
second message inside the first. Still inert in normal operation: nothing
marks work until Stage C.
Finding fixed here: amd64 sk_vm_switch_prime built the first-entry frame at
top-56, entering with rsp 16-aligned instead of the SysV-required 8 mod 16, so
the first aligned SSE spill in a callee took #GP (logs/20260923-142526, kept).
It had been latent since SXXVIII Stage 2 because the placeholder never called
anything. The frame is now at top-64 with a zeroed pad slot. aarch64 and
riscv64 were already correct.
Evidence: a temporary kernel_main probe (reverted, not in this commit) queued
two messages to Hestia, the first calling a colon word, and switched into her.
It passed on all three ISAs: 0 pending, parked_idle, depth 0, context saved on
her own stack, SB-SEQ=12 (drained one at a time, not nested), ledger and
stadium_conserved restored. Formal acceptance without the probe on all three
ISAs: dict_hash identical and unchanged, zero UNKNOWN WORD or faults, and the
live WIREBIND mint -> USE -> 1 2 + . -> 3 relay.
FABRIC-3.8.md also records Captain Bob's rulings that no VM-side word ever gives
up control and that multitasking is a compudynamic hybrid, and opens SS3.12
(VM frames for per-VM execution state).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Replaces the global g_vm_interpret_depth test at both execute_colon_word()
checkpoints (kernel-Hermes drain, switch-signal take) with
sk_vm_owns_outermost_frame(vm): the VM physically owns the stack
(sk_vm_switch_current_vm() == vm), is at its own outermost vm_interpret()
frame (new per-VM VM.interpret_depth), and is not compiling. Once VMs
interleave on their own native stacks, a global depth count across all VMs
no longer means "this VM owns this stack"; this is the invariant it was
approximating. The global and the old function stay until Stage I.
Acceptance, all three ISAs, foreground with the framebuffer visible, coupled
disk images reset before each: zero UNKNOWN WORD, zero self-test failures,
dict_hash identical across ISAs and unchanged from the pre-Stage-A boot, and
the live WIREBIND mint -> attach -> USE -> 1 2 + . -> 3 relay with
stadium_conserved(self)=true. Logs: 20260923-140120 (amd64), -140654
(aarch64), -141303 (riscv64).
FABRIC-3.8.md also records Captain Bob's ruling that preemption comes from
the compudynamics, not the timer: principle 5 is corrected and the design
question is opened as SS3.11, to be ruled before Stage C.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The per-ISA amd64 campaign (12345 3 S" amd64" DOE) was stopped ~49 min in,
zero trials complete: its harness drives workers by synchronous VM-EXEC on
Hera's stack, so the concurrency factor counted resident VMs while execution
stayed serialized. Tracing further showed the v2.1.0 reshuffle stops short of
real concurrency: kernel-Hermes never publishes eligibility (no mark_work in
sk_hermes_send_one), the switch trampoline is still the Stage-2 placeholder,
delivery to passive VMs still goes through the idle pump, only Tripod/WIREBIND
VMs are switch participants, and the stack-ownership gate is a single global.
FABRIC-3.8.md records the gap analysis and a staged A-I design, each stage its
own commit and 3-arch acceptance. FABRIC-3.md SXXXV.16 points to it. Logs and
extracted CSVs from today's boots and the stopped run are kept as audit
artifacts.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
