$ sudo virsh capabilities <capabilities> <host> <cpu> <arch>x86_64</arch> </cpu> <migration_features> <live/> <uri_transports> <uri_transport>tcp</uri_transport> </uri_transports> </migration_features> </host> <guest> <os_type>hvm</os_type> <arch name='i686'> <wordsize>32</wordsize> <emulator>/usr/bin/qemu</emulator> <machine>pc-0.11</machine> <machine canonical='pc-0.11'>pc</machine> <machine>pc-0.10</machine> <machine>isapc</machine> <domain type='qemu'> </domain> </arch> <features> <pae/> <nonpae/> <acpi default='on' toggle='yes'/> <apic default='on' toggle='no'/> </features> </guest> </capabilities>
Ok, this confirms your host OS is x86_64, but it only shows a single guest entry for i386. This is because the 'qemu' binar is the 32-bit emulator. To make x86_64 guests work, you need to install the qemu-system-x86_64 binary, or a KVM binary called 'kvm' or 'qemu-kvm'.
Once those are installed, you should see another <guest> appear in that capabilities XML
Unfortunately, I already have the 64bit emulator installed: $ which qemu-system-x86_64 /usr/local/bin/qemu-system-x86_64 $ ls -l /usr/local/bin/qemu-* -rwxr-xr-x 1 root root 217184 Jan 14 14:00 /usr/local/bin/qemu-img -rwxr-xr-x 1 root root 229120 Jan 14 14:00 /usr/local/bin/qemu-io -rwxr-xr-x 1 root root 210968 Jan 14 14:00 /usr/local/bin/qemu-nbd -rwxr-xr-x 1 root root 2323328 Jan 14 14:01 /usr/local/bin/qemu-system-x86_64 This was done by building the qemu-kvm-0.12.1.1 package from source. I am able to run this vm just fine using the qemu-system-x86_64 binary. I've tried rebuilding libvirt several times to make it aware that the proper binaries are installed, but it can't seem to find them for some reason.