Re: GUIX 0.7 under QEMU/KVM with virtio

[Assaf Gordon]

Hi,

Thanks for the help.
Some more details (replying out of order):

On 10/04/2014 04:42 PM, Ludovic Courtès wrote:

> > Is there a way to fix this? force the kernel to load virto driver?
>
> Currently all the drivers needed to mount the root partition must be
> explicitly loaded in the initrd.  So yes, you would need to have the
> virtio modules loaded from the initrd (info "(guix) Initial RAM Disk"):
>
>    (operating-system
>      ...
>      (initrd (lambda (file-systems . rest)
>                (apply base-initrd file-systems
>                       #:extra-modules '("virtio.ko" "virtio_ring.ko"
>                                         "virtio_blk.ko")
>                       rest))))
 
Two more things were needed:
1. adding"virtio_pci.ko" and "virtio_net.ko"  to the list of drivers.
2. Labeling "/dev/vda1" as "gnu-disk-image" (when doing "mkfs.ext4 -L").
   This wasn't needed to boot from "/dev/sda1", but was needed to use 
"/dev/vda1".
   Perhaps some hard-coded thing ?

With these, the VM boots with virtio disk and network.
> > After boot (before setup), I'm trying to get a login prompt on the serial port 
> > (which QEMU's redirect to the terminal).
> > I can do the following:
> >     echo "hello" > /dev/ttyS0   => appears on the terminal
> >
> > I can also boot with "console=ttyS0,9600n8" (in the GRUB command line), and the 
> > kernel messages appear on the console.
> > However, I can't get a login prompt on the serial console.
> >
> > I tried variations of:
> >     agetty -L 9600 ttyS0 linux
> >
> > But they all exit after a timeout of few seconds, and no prompt appears on the 
> > serial console.
> > Any ideas ?
>
> I haven’t tried agetty, but it seems to have a hard-coded default login
> program of “/bin/login”, which doesn’t exist here.  Could you try
> invoking it with -l $(guix build shadow)/bin/login ?
>
> Alternately you could try adding a mingetty service to the
> configuration:
>
>    (operating-system
>      ...
>      (services (cons (mingetty-service "ttyS0")
>                      %base-services)))

I still can't get serial console to work, perhaps needs more fidgeting.
Trying "mingetty ttyS0" from the command line fails with:
    ttyS0: no controlling tty: Operation not permitted
So I'm not sure 'mingetty' is the way to go.

I'm not well-versed in scheme, so it will take me some more time to figure 
things out...

-Assaf