GUIX 0.7 under QEMU/KVM with virtio

[Assaf Gordon <assafgordon@gmail.com>]

Hello Guix Developers,

I'm experimenting in using Guix under QEMU/KVM.

I've read these:
https://lists.gnu.org/archive/html/guix-devel/2014-09/msg00326.html
http://lists.gnu.org/archive/html/guix-devel/2014-09/msg00149.html

First,
I can provide another recipe:
   ## On Host
   $ wget ftp://alpha.gnu.org/gnu/guix/gnu-usb-install-0.7.x86_64.xz
   $ unxz gnu-usb-install-0.7.x86_64.xz
   $ qemu-img create -q -f qcow2 guix.qcow2 5G
   $ qemu-system-x86_64 --enable-kvm \
        -m 1024 \
        -net nic,model=virtio -net user \
        -boot menu=on \
        -hda gnu-usb-install-0.7.x86_64 \
        -drive file=guix.qcow2,if=virtio,media=disk,index=0 \
        -serial mon:stdio \
        -vga std

   ## Inside guest:
   1. Press F12 (quickly) for QEMU Boot menu
   2. Choose "1" for QEMU ATA DISK 750MB SIZE (which is the USB image)
   3. GRUB Loads, boots into Guix shell
   4. The USB drive is "/dev/sda1"
   5. The Disk image is "/dev/vda" (unpartitioned)
   6. Parition with fdisk:
      # fdisk /dev/vda
      press n (new partition)
      press p (primary partition)
      (use defaults for all values)
      a (activate parition)
      1 (parition number)
      w (write changes)
   7. Create File system
      #  mkfs.ext4 -L guix /dev/vda1
   8. Follow instructions at
      http://www.gnu.org/software/guix/manual/html_node/System-Installation.html
      # dhclient eth0
      # mount /dev/vda1 /mnt
      # deco start cow-store /mnt
      # guix system init /mnt/etc/config.scm /mnt
      (my 'config.scm' attached below)


Second,
I can confirm Nate's observation that using QEMU's "-usbdrive" option for the USB image causes everything to be VERY slow.
not sure why.
Using "-hda" for the USB image is much better.


Third,
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 ?


Fourth,
Sadly, after installation is complete, and after rebooting, the system fails to load from "/dev/vda1" (drops to "early boot guile").
Based on the kernel messages, it seems the "virtio_blk" driver is not loaded, and so "/dev/vda" is not available.
If I then switch QEMU parameters from "-drive if=virtio" to "-drive if=ide" the system loads fine (also requires changing grub's "--root" parameter).

Is there a way to fix this? force the kernel to load virto driver?




Regards,
  - Assaf


=== config.scm, adapted for "/dev/vda" ====
(use-modules (gnu))

(operating-system
   (host-name "guix07")
   (timezone "Europe/Paris")
   (locale "en_US.UTF-8")
   (bootloader (grub-configuration (device "/dev/vda")))
   (file-systems (cons (file-system
                         (device "/dev/vda1")
                         (mount-point "/")
                         (type "ext4"))
                       %base-file-systems))
   (users (list (user-account
                 (name "miles")
                 (group "users")
                 (supplementary-groups '("wheel"))
                 (home-directory "/home/miles")))))
=================