Running a QEMU Linux guest



QEMU provides 2 window buffers when invoked with “-nographic”

  • the QEMU monitor

can use this for various control/debugging operations (see QEMU documentation)

  • the guest’s serial port (typically /dev/ttyS0)

allows you to log in to QEMU guest, and to see console output
NOTE: you won’t be able to log in to your Linux guest unless the guest’s file system has been configured to support this (see below)

Important key sequences to know:

Ctrl-a c
switch between serial port and QEMU monitor window buffers

Ctrl-a x
terminate QEMU
alternate method: enter “quit” in the QEMU monitor window buffer

Ctrl-a s
save disk data back to file (overrides “-snapshot” option)

To enable logins via the guest’s serial port:
ensure the Linux guest’s /etc/inittab file has a line like the following:
T0:23:respawn:/sbin/getty -L ttyS0 38400 vt100
this tells Linux to listen for logins on /dev/ttyS0
there was already a line like this in the filesystem I was using, but it was commented out

To login to a Linux guest
Ubuntu provides default user of “root”, with no password (i.e. just hit enter when prompted)
NOTE: this process can vary, depending on the Linux distribution your guest’s file system has


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