1.使用物理机光驱

<disk type='block' device='cdrom'>
<driver name='qemu' type='raw'/>
<source dev='/dev/sr0'/>
<target dev='hdc' bus='ide'>
<readonly/>
</disk>

2.使用iso安装

<os>
<type arch='x86_64' machine='pc-1.1'>hvm</type>
<boot dev='cdrom'/>
<boot dev='hd'/>
</os>

<disk type='file' device='cdrom'>
<driver name='qemu' type='raw'/>
<source file='/home/cloud/ubuntu.iso'/>
<target dev='hdc' bus='ide'/>
<readonly/>
</disk>

3.使用物理硬盘

<disk type='block' device='disk'>
<driver name='qemu' type='raw'/>
<source dev='/dev/sda'/>
<target dev='hda' bus='ide'/>
</disk>

4.嵌套kvm

http://www.google.com/url?sa=t&rct=j&q=%20kvm_intel%20not%20loadable%20in%20nested&source=web&cd=5&cad=rja&ved=0CEUQFjAE&url=http%3a%2f%2fkashyapc.wordpress.com%2f2012%2f01%2f14%2fnested-virtualization-with-kvm-intel%2f&ei=5jXaUaW3E8iUiQeGz4GIDg&usg=AFQjCNHauihEhS4GW31533yKGKB2N4lDcQ&bvm=bv.48705608,d.aGc

http://www.rdoxenham.com/?p=275

<cpu match='exact'>
  <model>Westmere</model>
 <feature policy='require' name='vmx'/>
</cpu>