To avoid QEMU being terminated on SIGINT (Ctrl+c), instead of just
stdio, supply the special parameter
QEMU includes a built-in monitor that can inspect and modify the machine state in useful ways. To enter the monitor, press
Ctrl-a c in the terminal running QEMU. Press
Ctrl-a c again to switch back to the serial console.
For a complete reference to the monitor commands, see the QEMU manual.