Files
bfe-core1106-sdk/qemu/README.md
T
NoahandClaude Fable 5.1 9b6428db47 qemu: start every panel daemon, and keep Modbus off the control channel
Stage-2 init started only warden-flared and warden-modbus from the
payload, so every daemon-backed screen (Automation, MikroTik, Mining,
RS485, Starlink, Services) sat in its "not running" state on the rig
while the bench panel showed the daemons up with nothing attached. It now
starts every warden-* daemon it finds in the panel's own S-number order
(ai, automation, modbus, mikrotik, asic, starlink, stratum, flared), each
with no arguments as start-stop-daemon runs them on the panel. flare-edge
tools/rig-pull-daemons.sh copies a panel's static binaries in.

Doing that exposed a latent alias: init pointed warden-modbus's /dev/ttyS4
at /dev/ttyS0 whenever ttyS0 existed, and with --ctl that port IS the
control channel, so Modbus polls arrived inside the wake reply and the
bridge hung. run.sh now always attaches an RS485 pci-serial (a null
chardev without --rs485), and init aliases ttyS4 to ttyS1 when warden.ctl
is on the cmdline, ttyS0 otherwise.

Verified on a boot with all eight daemons: status json reports
automation.engine, mikrotik.backend, mining.available and rs485.available
true with the Modbus scan sweeping the empty UART; six daemon-backed pages
matched screenshots of the bench panel structurally (0/256 cells differ).

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013aHKWzT5EF86RFKRMtAv9n
2026-09-08 00:47:08 -06:00

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7.3 KiB
Markdown

# The Device Simulator
A QEMU virtual machine that boots the real forward-ported kernel and real
userspace: the 86 Panel (init, daemons, networking, OTA, watchdog, display)
developed and tested with no board attached. The third simulator in the stack
(three-way split: root README), deliberately not named "sim": it runs the
whole machine above the kernel entry point on real binaries: bring your own,
or drop prebuilt payloads in `payload/`. Decision record: ADR-0006.
## The Boundary
There is no RV1106 machine model in QEMU and everything below the kernel is
closed rkbin blobs plus mask ROM, so the VM **enters at `-kernel zImage`** on
`-M virt,highmem=off` (single Cortex-A7, 256M: the RV1106G3's shape).
| Emulated / substituted | Not emulated (stays bench / `sim/` territory) |
|---|---|
| Kernel boot, init ordering, switch_root | BootROM, idblock/DDR-init, SPL, U-Boot |
| A/B *outcome* (`warden.slot=` cmdline) | Real BCB A/B selection, bootcount auto-revert |
| Storage: virtio-blk with the device's exact `blkdevparts=` layout + `/dev/block/by-name/` contract | eMMC controller itself |
| Network: virtio-net (slirp, hostfwd 22/80/28443) | GMAC, AIC8800 wifi, usb0 gadget |
| Display: virtio-gpu 720x720 via fbdev emulation | VOP/RGB666 pipeline, CH32V003 panel init, RGA blits |
| Touch: virtio-tablet (QMP `input-send-event`) | GT911 on I2C3 |
| Watchdog: i6300esb (PCI), `-action watchdog=reset` | DW watchdog @0xff5a0000, HPMCU supervisor |
| RS485: pci-serial chardev bridged to `sim/`'s `ModbusSlave` | Real UART4 timing/electrical behavior |
| RTC: PL031 (`--rtc` reproduces the no-RTC 2021-clock incident class) | The unpopulated backup-cell reality |
**"Boots/works under emulation" is never evidence of "works on silicon."**
The VM narrows which claims need a panel; on-device claims still need
on-device evidence. Conversely, the VM is the first environment that runs
production binaries on a non-RV1106 memory map: it found flare-edge #106
(fatal SIGBUS in flared's HPMCU probe) and #107 (Y2038 time_t truncation)
on its first two boots of real userspace.
Documented guest deviations from production, set by stage-2 init:
`WARDEN_FLARE_INSECURE=1` (the desk mock portal is plain HTTP) and
`WARDEN_HPMCU=0` (no mailbox SRAM on virt; flared >= flare-edge#106 fix
required, or the daemon dies of SIGBUS).
**The VM's kernel is ahead of the panels' in one way that shows in the UI.**
It is built from `build/warden_defconfig` plus `configs/virt.fragment`, so it
has `CONFIG_BRIDGE`; the vendor 5.10 kernel most panels still run does not.
A Client-mode access point is bridged to the wired uplink and needs that, so
the Wi-Fi page offers it in the VM and says "Needs Router mode: this kernel
cannot bridge" on a 5.10 panel. Both are correct for the kernel underneath.
The difference disappears as panels move to the 6.18 build, but until then a
screenshot from here is not evidence about a 5.10 panel's Wi-Fi page.
## Quick Start
```sh
# 1. kernel: canonical build boots the VM as-is; the fragment variant adds
# the scenario devices (PCI serial, watchdog, WireGuard, virtio-gpu/input)
WORK=$HOME/kbuild-out CROSS_COMPILE=arm-linux-gnueabihf- \
WARDEN_KCONFIG_FRAGMENT=qemu/configs/virt.fragment bash build/build-kernel.sh
# 2. initramfs (sha256-pinned static busybox + qemu/rootfs/) and A/B disk
bash qemu/mkinitramfs.sh
bash qemu/mkimage.sh # options: --portal-url --state K=V --fw-version
# 3. run (see run.sh header for all flags)
bash qemu/run.sh --kernel $HOME/kbuild-out/linux-6.18.46/arch/arm/boot/zImage --shell
```
Payload: drop static musl armv7 binaries into `qemu/payload/` (see its
README). Stage-2 init starts every panel daemon it finds, in the panel's own
S-number order (`warden-ai`, `warden-automation`, `warden-modbus`,
`warden-mikrotik`, `warden-asic`, `warden-starlink`, `warden-stratum`,
`warden-flared`), then `warden-ui` (the LVGL fbdev+evdev build from
flare-edge `tools/build-ui-vm.sh`). The quickest faithful payload is the
daemons a bench panel already runs: flare-edge `tools/rig-pull-daemons.sh
--host <panel>` copies them in. The RS485 UART is always present (a null
chardev without `--rs485`), so `warden-modbus` polls a port with nothing on
it, as on a panel with an empty header, and never the control channel.
The VT cursor is kept off (`vt.global_cursor_default=0`): fbcon shares the
virtio-gpu framebuffer with warden-ui and its blinking cursor would otherwise
show up in screendumps at random (issue #18).
## Scenarios
All take the virt-fragment `<zImage>`; `FLARE_EDGE=<checkout>` where noted.
| Scenario | Needs | Proves |
|---|---|---|
| `boot-smoke.sh` | - | sentinel-asserting boot; runs in CI inside kernel-build |
| `portal-scenario.sh` | `FLARE_EDGE` | real flared against the desk mock portal: authenticated check-in, desired-state pull, signed tier-1 `.wfw` download; verify/stage/APPLYING as a dry run (no `WARDEN_FW_ALLOW_APPLY`) |
| `ota-apply.sh` | `FLARE_EDGE` | the FULL apply: the `.wfw`'s bootable rootfs payload is written to rootfs_b (`run.sh --allow-apply` gates it per boot), the AvbABData in `misc` flips, and slot `_b` boots the applied version |
| `ui-shot.sh` | - | display+touch, headless: QMP-screendumps the 720x720 UI, taps the Metrics tab via `input-send-event`, asserts the frame changed (`qmp.py` is the QMP client) |
| `ui-drive.sh <script>` | - | the same rig for a SEQUENCE: boots once, runs a `qmp.py drive` script of taps/swipes/screenshots in panel pixels, and FAILS if warden-ui died on the way (stage-2 init announces the exit on the console). `tests/scripts/nav-stress.txt` is the navigation regression: it reproduces the s_row_left overflow that segfaulted the UI on returning to Settings > Apps |
| `real-image-boot.sh` | matched `rootfs.img` + `oem.img` | an ACTUAL flare-edge build (placed by `mkimage.sh --rootfs-image/--oem-image`) boots its own init chain to getty; binaries predating known fixes reproduce their bugs faithfully, a time machine for field issues |
| watchdog (`run.sh --watchdog`) | - | arm `/dev/watchdog`, don't pet: the VM resets ~30 s later (verified) |
Scenario fine print:
- OTA: the BCB slot CHOICE and the physical reset stay emulated by the
harness (ADR-0006 boundary); the VM exports `WARDEN_HARD_RESET=0` so
flared's post-apply reset surfaces as a reported error, not a /dev/mem
fault.
- Touch injection holds 200 ms: an instantaneous press+release lands inside
one LVGL poll and never clicks.
- Watchdog + a flared payload don't mix: flared pets only while the UI
heartbeat is fresh.
## Gotchas
- AF_UNIX socket paths cap at ~108 chars; keep `--rs485`/`--qmp` paths short.
- A serial port that is closed discards incoming bytes: hold ONE fd open
across write and read when scripting the guest side of the RS485 bridge.
- `highmem=off` and `-global virtio-mmio.force-legacy=false` are required
(32-bit ECAM reach; virtio-1-only gpu/input); both live ONLY in run.sh,
which every script (boot smoke included) delegates to.
- Never pass `earlyprintk`: DEBUG_UART_PHYS is the RV1106's 0xff4c0000.
## Requirements
`qemu-system-arm` (Debian 13 ships QEMU 10), `curl`, `cpio`, `mkfs.ext4`,
`gcc-arm-linux-gnueabihf` (kernel build), `python3` (+`cryptography` for the
portal scenario's `.wfw` signing). CI: the hosted `qemu-tools` job builds the
tooling; the boot smoke runs inside the (also hosted, dispatch-only)
`kernel-build` job, which apt-installs its own toolchain and qemu (ADR-0007).