kvm boot debian from initramfs

kvm-initramfs.sh

#!/bin/bash
set -e
cd /tmp
mkdir testroot
debootstrap wheezy testroot http://http.debian.net/debian
chroot testroot env LC_ALL=C apt-get install --no-install-recommends linux-image-amd64
rm -rf testroot/var/cache/apt/*
ln -s bin/bash testroot/init
echo 'T0:23:respawn:/sbin/getty -L ttyS0 115200 vt100' >>testroot/etc/inittab
passwd -R "$(pwd)"/testroot -d root
echo 'testroot' >testroot/etc/hostname
echo 'auto eth0' >>testroot/etc/network/interfaces
echo 'iface eth0 inet dhcp' >>testroot/etc/network/interfaces
( cd testroot && find . -print0 | cpio --null -ov --format=newc | gzip -9 > ../testroot.gz )
kvm -m 1024 -kernel testroot/boot/vmlinuz-* -initrd testroot.gz -append 'console=ttyS0' -nographic -net nic,model=virtio -net user

# To continue with normal init, run:
# exec /sbin/init