I've been looking into the parts of virtinst which try to probe the capabilities of the host directly, rather than being abstracted through libvirt (for example, opening and parsing /sys/hypervisor/properties/capabilities directly). Attached is a proposed API for probing the capabilities and supported guest architectures of the hypervisor / driver. I've implemented the virCapabilities part already. My original implementation of the guest architectures had virCapabilities containing a list of supported architectures, but that doesn't nearly cover the richness of what the underlying drivers could support, so I'm currently separating that out into a separate virConnectGetGuestArchitectures call. Let me know your opinions of this API. As an aside, the current virt-manager "choose paravirt / fullvirt" screen doesn't really capture the full, shall I say, ugliness of the possible choices for architecture, particularly when we add qemu, kqemu, and emulation in the mix. I suspect that presenting a list of architectures here, perhaps with some options to show only paravirt, show only fullvirt, show only accelerated ... Rich. -- Emerging Technologies, Red Hat http://et.redhat.com/~rjones/ 64 Baker Street, London, W1U 7DF Mobile: +44 7866 314 421 "[Negative numbers] darken the very whole doctrines of the equations and make dark of the things which are in their nature excessively obvious and simple" (Francis Maseres FRS, mathematician, 1759)