QEMU 10's virtserialport on a socket chardev (server=on,wait=off)
silently drops guest→host bytes. Reproduced cleanly: writes from
inside the guest to /dev/vport<N>p<M> succeed (no errno) but the
connected client socket receives 0 bytes. Same bug whether the
client is a single recv loop, multiple threads, TCP or UNIX socket,
or whether QEMU runs as server vs client. virtconsole on the same
socket works fine — only virtserialport is broken.
Workaround: use `pipe` chardev (a pair of named FIFOs created
beforehand by qemu_manager). guest→host through .out flows reliably
in QEMU 10 — verified with manual test: 'echo PIPE_TEST > /dev/vport1p1'
in the guest produces 'PIPE_TEST\n' immediately on the host side.
Changes:
- qemu_manager._boot: allocate a temp basename, mkfifo .in + .out,
pass to QEMU as 'pipe,path=<base>'.
- qemu_manager._connect_gpio: open both FIFOs O_RDWR | O_NONBLOCK on
host side (O_RDWR keeps the FIFOs open even when guest hasn't
opened its side yet), wire .out into asyncio via loop.add_reader.
- qemu_manager._reply_gpio / _send_gpio: write to .in fd via os.write.
- qemu_manager._handle_gpio_line: extended Phase 1 GPIO-only parser
into a full Phase 2 mux: GPIO/GPIO_SETUP/GPIO_IN/PWM_*/I2C/SPI/UART
with appropriate replies.
- qemu_manager._shutdown: close FDs + unlink the FIFOs.
- manifest.json: bump raspberry-pi-3-virt rootfs to 2026.05+phase2-shims
(the new rootfs ships the velxio shim Python modules under
/usr/lib/velxio-shims/).
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