<os> <type>hvm</type> <loader>/usr/lib/xen/boot/hvmloader</loader> <boot dev='network'/> <boot dev='cdrom'/> <boot dev='hd'/> <bootmenu enable='yes'/> </os>
Which means the boot order is:
boot from network like PXE boot
boot from CD-ROM if no PXE boot
boot from local hard disk if no PXE boot nor bootable CD
加上以上配置后,F12 可以选择启动顺序