Mine

memory=256
vcpus=1
uuid="c72279c6-6568-039f-aeb6-703d81c0aa85"
on_crash="destroy"
on_poweroff="destroy"
on_reboot="restart"
localtime=0

builder="hvm"
device_model="/usr/lib/xen/bin/qemu-dm"
kernel="/usr/lib/xen/boot/hvmloader"
boot="c"
disk=[ 'file:/var/lib/xen/images/debian/disk0,hda,w', 'phy:/dev/cdrom,hdc:cdrom,r', ]
vif=[ 'mac=00:16:3e:62:5d:55,model=rtl8139,type=ioemu', ]
pci = ['f,4,0']
vnc=1
vncunused=1
apic=0
acpi=1
pae=1