On Tue, Apr 13, 2010 at 3:09 PM, Alexander Graf <agraf at suse.de> wrote: > no idea what the io zones are, but in general you just don't register MMIO regions. You only register memory slots and that should all be done automatically by the existing generic kvm code. Then how do you know inside KVM if the guest had a mapping to non-existing memory or a mapping to an MMIO region? Do you simply forward all accesses to 'unregistered' guest physical addresses to QEMU?