qemu command line for installation

[Gábor Boskovits]

Hello Laura,

I've tried to reproduce the issues you mentioned locally, and to be
honest with success :)

Issue 1: /dev/sda already partitioned:
The order of options on the command line made the installer image
/dev/sda, and it is really
partitioned.

I avoided it using explicit mapping of drives on the bus.
This then led to bad boot order, so I fixed that using bootindex.

Issue2: floppy disk errors:
This is because qemu by default creates a floppy device.

I suspended this using -nodefaults.
This then led to no video device, so I added one.

The final command looks like this:

qemu-system-x86_64 \
    -m 1024 \
    -nodefaults \
    -drive file=hda.img,format=raw,if=none,id=drive-ide0-0-0 \
    -device ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1
\
    -drive 
file=guixsd-install-0.15.0.x86_64-linux.iso,format=raw,if=none,id=drive-ide0-0-1,readonly=on
\
    -device ide-cd,bus=ide.0,unit=1,drive=drive-ide0-0-1,id=ide0-0-1,bootindex=2
\
    -device qxl-vga

This makes sure that the floppy is not created, so there are no errors
because of that,
the hdd is on /dev/sda, the installer image is read only, shown as a
cdrom, is on /dev/sr0.
On the first run the cdrom is booted, when the hdd becomes bootable
that is booted instead.
You might need to adjust the format parameters.

There is still a slight annoyance, this shows up in the starting terminal:
qemu-system-x86_64: warning: TCG doesn't support requested feature:
CPUID.01H:ECX.vmx [bit 5]
This is the result of Ubuntu configuration of their qemu package.

I decided to CC the list, so that we can discuss if these chevats are
worthy to be documented somewhere or not.

Best regards,
g_bor