[Bug] VM exits on boot with AVF backend on Pixel 8a

[ongyx]

Description

On a fresh installation, attempting to launch the VM using the AVF backend on a Pixel 8a (akita) causes the VM to exit on boot.

Steps to Reproduce

Steps to reproduce the behavior:

1. Install Podroid and finish the intial setup
2. Try to launch the VM using AVF
3. See error message

Expected Behavior

The VM launches.

Actual Behavior

The message VM exited during boot (reason=5).

Diagnostic Log

log.txt

Additional Context

In the AVF source code, error 5 corresponds to the constant STOP_REASON_REBOOT, suggesting it could be some kind of kernel panic in the VM. I'm not sure if it's possible to get logs from inside the VM itself to diagnose the issue?

[ExTV]

Thanks for the detailed report — log + akita fingerprint + reason=5 is exactly the info I needed.

Strong hypothesis: the v1.2.0 build points the guest console at virtio-console (console=hvc0 + setConsoleInputDevice("hvc0")) for TUI throughput. crosvm on Pixel 10 exposes hvc0; the AVF revision on Pixel 8/8a apparently does not, so the guest can't find the console device and reboots before any output is captured — which matches STOP_REASON_REBOOT (5) plus the empty console.log you sent.

I just shipped a diagnostic-only prerelease: v1.2.1. AvfEngine now writes guest console bytes to console.log (it didn't before — separate gap that masked this).

Could you:

1. Install v1.2.1 over v1.2.0 (same signing key — in-place update, your settings + storage are preserved).
2. Settings → Advanced → "Kernel extra cmdline": remove loglevel=1 quiet for this run (otherwise the panic message gets suppressed).
3. Hit Start once, let it fail, then Export diagnostic and attach the new log here. The console.log section should now contain the actual kernel panic.

Workaround while you wait: Settings → Advanced → Backend → QEMU (TCG). That path is software-emulated (slower) but doesn't go anywhere near hvc0.

[ExTV]

hi check the new version and report back if it worked for u

[ongyx]

Strange, there's still no output from the VM: log (2).txt

[ExTV]

Check out my latest release

[ongyx]

No dice, the VM still doesn't boot:
log (4).txt

[ExTV]

Thanks - the v1.2.2 log narrows it down a lot.

The console capture is actually working now: the export writes console.log on every AVF boot. The reason it still looks empty is that the guest resets before it prints anything - it dies ~960 ms after start with STOP_REASON_REBOOT and zero console bytes. (The "no console.log" line in the export is misleading - it also shows when the file is present but empty, which is your case. I'll fix that wording.)

Empty console + sub-second reboot means the VM is resetting before the virtio-console device (hvc0) comes up in early boot, which is exactly why no panic text ever reaches the log. On Pixel 10 the guest gets far enough to reach hvc0; akita's hypervisor apparently doesn't.

One experiment I'd like you to try (this is a real behavioral change, not just diagnostics):

1. Settings -> CPU cores -> 1
2. Confirm Backend is still AVF
3. Hit Start, let it settle, then Export diagnostic and attach the new log

Why: with more than 1 core we hand AVF MATCH_HOST, which on the Tensor G3 is a 9-core heterogeneous (big.LITTLE) topology. Secondary-CPU bringup happens very early in boot - before the console is up - so if crosvm on akita trips there, a single vCPU sidesteps it. If it boots with 1 core, we've found the trigger.

If 1 core doesn't change anything, the next step is on me: a prerelease that routes early boot output to the serial UART with earlycon so we can finally capture the panic itself (the current build only captures hvc0, which is too late).

Stopgap meanwhile: Settings -> Advanced -> Backend -> QEMU (TCG) still works (software-emulated, slower) if you just need the container runtime.

[ongyx]

Yup, I can confirm the VM boots with 1 vCPU! Not sure why it crashes with multiple vCPUs though: log (5).txt

[ExTV]

Thats a great news i will work on this more then report back .

[Vazgen005]

Can confirm. Same problem on Pixel 8 Pro