How to turn on VT-d in Xen 1 ) cd xen-unstable.hg 2 ) make install 3 ) make linux-2.6-xen-config CONFIGMODE=menuconfig 4 ) change XEN->"PCI-device backend driver" from "M" to "*". 5 ) make linux-2.6-xen-build 6 ) make linux-2.6-xen-install 7 ) depmod 2.6.18.8-xen 8 ) mkinitrd -v -f --with=ahci --with=aacraid --with=sd_mod --with=scsi_mod initrd-2.6.18-xen.img 2.6.18.8-xen 9 ) cp initrd-2.6.18-xen.