[arch-general] Qemu / KVM 9p rootfs not booting automatically

[H8H]

On 10/06/2015 08:55 AM, Martti Kühne wrote:
> Kernel parameter root= appears to be missing. Unless you know for
> absolutely certain that the early userspace is capable to figure out
> the root partition on its own, you'd rather put it into your
> bootloader's config.

Thanks but I don't have any bootloader config nor need any[1]. The
parameter should handle anything initramfs needs

  -append 'root=r rw rootfstype=9p rootflags=trans=virtio console=ttyS0'

In my opinion with `root=r` it defines root, where `r` is the mount_tag:

` -virtfs
local,id=r,path=/root/arch,security_model=passthrough,mount_tag=r,'

the mountpoint is /root/arch (on the hostsystem)

On the recovery shell I can type

mount -t 9p -o trans=virtio r new_root/

and `r` does exactly what I want, it mounts `r` which is /root/arch on
the host system to the `new_root` directory as a VirtFs Filesystem.

So I don't know why I does not find `r` by itself:
ERROR: device 'r' not found. Skipping fsck.
ERROR: Unable to find root device 'r'.

Do I have to 'swap' anything in here?
MODULES="9p 9pnet virtio virtio_blk virtio_pci virtio_net"
HOOKS="base udev block autodetect modconf filesystems keyboard fsck"

[1] (see section Can 9p used as root file system?)
http://blog.allenx.org/2015/07/03/virtio-9p-note/

Cheers

Chris