I converted qcow2 image to raw and changed I/O bus to VirtIO for a VM. now I can't boot that VM. I Installed VirtIO driver with following command:
mkinitrd --with virtio_pci --with virtio_blk -f /boot/initrd-$(uname -r).img $(uname -r) and these are related kernel modules:
virtio_balloon 11329 0 virtio_blk 11593 3 virtio_pci 11845 0 virtio_ring 8513 1 virtio_pci virtio 9541 3 virtio_balloon,virtio_blk,virtio_pci and this is what happens during boot-up.

I also changed /boot/grub/device.map from "(hd0) /dev/sda" to "(hd0) /dev/vda"
but problem still exists. any ideas how to fix this ?
This is my default option to boot:
title CentOS (2.6.18-308.13.1.el5) root (hd0,0) kernel /vmlinuz-2.6.18-308.13.1.el5 ro root=/dev/VolGroup00/LogVol00 initrd /initrd-2.6.18-308.13.1.el5.img