qemu, starting a serial console in Linux for login

Does anyone know the options for getting a login prompt on a serial console in Linux when running under qemu?

I tried using -nographic, but I only get the GRUB menu and never reach a login prompt. I believe the approach using -serial requires specifying a kernel image directly, which is not what I'm trying to do.

I think this is instead a matter of passing the correct kernel command-line arguments from GRUB, such as console=ttyS0.