Items still outstanding: * ~~Making sure large guests can't exhaust dom0 memory~~ * Passthrough for DomUs when using a PVH dom0 * SRIOV support for dom0 * ~~Serial console based on PCI card for PVH dom0 (a.k.a. handle hidden devices).~~ * ~~Handing through video information (?)~~ * Add vPCI support to BAR resize PCI capability.