Hi Christian, here's the requested data below. This is with Xenial and Ocata. It has worked with Xenial and Mitaka.

ubuntu@phanpy:~$ virsh capabilities
<capabilities>

  <host>
    <uuid>12ded42d-2831-44a4-b0ba-cc3af3481077</uuid>
    <cpu>
      <arch>aarch64</arch>
      <topology sockets='1' cores='48' threads='1'/>
      <pages unit='KiB' size='4'/>
      <pages unit='KiB' size='2048'/>
    </cpu>
    <power_management/>
    <migration_features>
      <live/>
      <uri_transports>
        <uri_transport>tcp</uri_transport>
        <uri_transport>rdma</uri_transport>
      </uri_transports>
    </migration_features>
    <topology>
      <cells num='1'>
        <cell id='0'>
          <memory unit='KiB'>131989624</memory>
          <pages unit='KiB' size='4'>32997406</pages>
          <pages unit='KiB' size='2048'>0</pages>
          <distances>
            <sibling id='0' value='10'/>
          </distances>
          <cpus num='48'>
            <cpu id='0' socket_id='0' core_id='0' siblings='0'/>
            <cpu id='1' socket_id='0' core_id='1' siblings='1'/>
            <cpu id='2' socket_id='0' core_id='2' siblings='2'/>
            <cpu id='3' socket_id='0' core_id='3' siblings='3'/>
            <cpu id='4' socket_id='0' core_id='4' siblings='4'/>
            <cpu id='5' socket_id='0' core_id='5' siblings='5'/>
            <cpu id='6' socket_id='0' core_id='6' siblings='6'/>
            <cpu id='7' socket_id='0' core_id='7' siblings='7'/>
            <cpu id='8' socket_id='0' core_id='8' siblings='8'/>
            <cpu id='9' socket_id='0' core_id='9' siblings='9'/>
            <cpu id='10' socket_id='0' core_id='10' siblings='10'/>
            <cpu id='11' socket_id='0' core_id='11' siblings='11'/>
            <cpu id='12' socket_id='0' core_id='12' siblings='12'/>
            <cpu id='13' socket_id='0' core_id='13' siblings='13'/>
            <cpu id='14' socket_id='0' core_id='14' siblings='14'/>
            <cpu id='15' socket_id='0' core_id='15' siblings='15'/>
            <cpu id='16' socket_id='0' core_id='16' siblings='16'/>
            <cpu id='17' socket_id='0' core_id='17' siblings='17'/>
            <cpu id='18' socket_id='0' core_id='18' siblings='18'/>
            <cpu id='19' socket_id='0' core_id='19' siblings='19'/>
            <cpu id='20' socket_id='0' core_id='20' siblings='20'/>
            <cpu id='21' socket_id='0' core_id='21' siblings='21'/>
            <cpu id='22' socket_id='0' core_id='22' siblings='22'/>
            <cpu id='23' socket_id='0' core_id='23' siblings='23'/>
            <cpu id='24' socket_id='0' core_id='24' siblings='24'/>
            <cpu id='25' socket_id='0' core_id='25' siblings='25'/>
            <cpu id='26' socket_id='0' core_id='26' siblings='26'/>
            <cpu id='27' socket_id='0' core_id='27' siblings='27'/>
            <cpu id='28' socket_id='0' core_id='28' siblings='28'/>
            <cpu id='29' socket_id='0' core_id='29' siblings='29'/>
            <cpu id='30' socket_id='0' core_id='30' siblings='30'/>
            <cpu id='31' socket_id='0' core_id='31' siblings='31'/>
            <cpu id='32' socket_id='0' core_id='32' siblings='32'/>
            <cpu id='33' socket_id='0' core_id='33' siblings='33'/>
            <cpu id='34' socket_id='0' core_id='34' siblings='34'/>
            <cpu id='35' socket_id='0' core_id='35' siblings='35'/>
            <cpu id='36' socket_id='0' core_id='36' siblings='36'/>
            <cpu id='37' socket_id='0' core_id='37' siblings='37'/>
            <cpu id='38' socket_id='0' core_id='38' siblings='38'/>
            <cpu id='39' socket_id='0' core_id='39' siblings='39'/>
            <cpu id='40' socket_id='0' core_id='40' siblings='40'/>
            <cpu id='41' socket_id='0' core_id='41' siblings='41'/>
            <cpu id='42' socket_id='0' core_id='42' siblings='42'/>
            <cpu id='43' socket_id='0' core_id='43' siblings='43'/>
            <cpu id='44' socket_id='0' core_id='44' siblings='44'/>
            <cpu id='45' socket_id='0' core_id='45' siblings='45'/>
            <cpu id='46' socket_id='0' core_id='46' siblings='46'/>
            <cpu id='47' socket_id='0' core_id='47' siblings='47'/>
          </cpus>
        </cell>
      </cells>
    </topology>
    <secmodel>
      <model>apparmor</model>
      <doi>0</doi>
    </secmodel>
    <secmodel>
      <model>dac</model>
      <doi>0</doi>
      <baselabel type='kvm'>+64055:+117</baselabel>
      <baselabel type='qemu'>+64055:+117</baselabel>
    </secmodel>
  </host>

  <guest>
    <os_type>hvm</os_type>
    <arch name='armv7l'>
      <wordsize>32</wordsize>
      <emulator>/usr/bin/qemu-system-arm</emulator>
      <machine maxCpus='1'>integratorcp</machine>
      <machine maxCpus='2'>nuri</machine>
      <machine maxCpus='1'>verdex</machine>
      <machine maxCpus='1'>ast2500-evb</machine>
      <machine maxCpus='2'>smdkc210</machine>
      <machine maxCpus='1'>collie</machine>
      <machine maxCpus='1'>imx25-pdk</machine>
      <machine maxCpus='1'>spitz</machine>
      <machine maxCpus='4'>realview-pbx-a9</machine>
      <machine maxCpus='1'>realview-eb</machine>
      <machine maxCpus='1'>versatilepb</machine>
      <machine maxCpus='1'>realview-pb-a8</machine>
      <machine maxCpus='1'>musicpal</machine>
      <machine maxCpus='1'>z2</machine>
      <machine maxCpus='1'>akita</machine>
      <machine maxCpus='255'>virt-2.7</machine>
      <machine maxCpus='1'>kzm</machine>
      <machine maxCpus='255'>virt-2.8</machine>
      <machine canonical='virt-2.8' maxCpus='255'>virt</machine>
      <machine maxCpus='4'>realview-eb-mpcore</machine>
      <machine maxCpus='1'>sx1</machine>
      <machine maxCpus='1'>sx1-v1</machine>
      <machine maxCpus='255'>virt-2.6</machine>
      <machine maxCpus='1'>cubieboard</machine>
      <machine maxCpus='4'>highbank</machine>
      <machine maxCpus='4'>raspi2</machine>
      <machine maxCpus='1'>netduino2</machine>
      <machine maxCpus='1'>terrier</machine>
      <machine maxCpus='1'>n810</machine>
      <machine maxCpus='1'>mainstone</machine>
      <machine maxCpus='1'>palmetto-bmc</machine>
      <machine maxCpus='4'>sabrelite</machine>
      <machine maxCpus='4'>midway</machine>
      <machine maxCpus='1'>cheetah</machine>
      <machine maxCpus='1'>tosa</machine>
      <machine maxCpus='1'>borzoi</machine>
      <machine maxCpus='1'>versatileab</machine>
      <machine maxCpus='1'>lm3s6965evb</machine>
      <machine maxCpus='1'>n800</machine>
      <machine maxCpus='1'>connex</machine>
      <machine maxCpus='1'>xilinx-zynq-a9</machine>
      <machine maxCpus='4'>vexpress-a9</machine>
      <machine maxCpus='4'>vexpress-a15</machine>
      <machine maxCpus='1'>canon-a1100</machine>
      <machine maxCpus='1'>lm3s811evb</machine>
      <domain type='qemu'/>
      <domain type='kvm'>
        <emulator>/usr/bin/qemu-system-aarch64</emulator>
        <machine maxCpus='1'>integratorcp</machine>
        <machine maxCpus='2'>nuri</machine>
        <machine maxCpus='1'>verdex</machine>
        <machine maxCpus='1'>ast2500-evb</machine>
        <machine maxCpus='2'>smdkc210</machine>
        <machine maxCpus='1'>collie</machine>
        <machine maxCpus='1'>imx25-pdk</machine>
        <machine maxCpus='1'>spitz</machine>
        <machine maxCpus='4'>realview-pbx-a9</machine>
        <machine maxCpus='1'>realview-eb</machine>
        <machine maxCpus='1'>versatilepb</machine>
        <machine maxCpus='1'>realview-pb-a8</machine>
        <machine maxCpus='1'>musicpal</machine>
        <machine maxCpus='1'>z2</machine>
        <machine maxCpus='1'>akita</machine>
        <machine maxCpus='255'>virt-2.7</machine>
        <machine maxCpus='1'>kzm</machine>
        <machine maxCpus='255'>virt-2.8</machine>
        <machine canonical='virt-2.8' maxCpus='255'>virt</machine>
        <machine maxCpus='4'>realview-eb-mpcore</machine>
        <machine maxCpus='1'>sx1</machine>
        <machine maxCpus='1'>sx1-v1</machine>
        <machine maxCpus='255'>virt-2.6</machine>
        <machine maxCpus='1'>cubieboard</machine>
        <machine maxCpus='4'>highbank</machine>
        <machine maxCpus='4'>raspi2</machine>
        <machine maxCpus='1'>netduino2</machine>
        <machine maxCpus='1'>terrier</machine>
        <machine maxCpus='1'>n810</machine>
        <machine maxCpus='1'>mainstone</machine>
        <machine maxCpus='1'>palmetto-bmc</machine>
        <machine maxCpus='4'>sabrelite</machine>
        <machine maxCpus='4'>midway</machine>
        <machine maxCpus='1'>cheetah</machine>
        <machine maxCpus='1'>tosa</machine>
        <machine maxCpus='1'>borzoi</machine>
        <machine maxCpus='1'>versatileab</machine>
        <machine maxCpus='1'>lm3s6965evb</machine>
        <machine maxCpus='1'>n800</machine>
        <machine maxCpus='1'>connex</machine>
        <machine maxCpus='1'>xilinx-zynq-a9</machine>
        <machine maxCpus='1'>xlnx-ep108</machine>
        <machine maxCpus='4'>vexpress-a9</machine>
        <machine maxCpus='4'>vexpress-a15</machine>
        <machine maxCpus='1'>xlnx-zcu102</machine>
        <machine maxCpus='1'>canon-a1100</machine>
        <machine maxCpus='1'>lm3s811evb</machine>
      </domain>
    </arch>
    <features>
      <cpuselection/>
      <deviceboot/>
      <disksnapshot default='on' toggle='no'/>
    </features>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='aarch64'>
      <wordsize>64</wordsize>
      <emulator>/usr/bin/qemu-system-aarch64</emulator>
      <machine maxCpus='1'>integratorcp</machine>
      <machine maxCpus='2'>nuri</machine>
      <machine maxCpus='1'>verdex</machine>
      <machine maxCpus='1'>ast2500-evb</machine>
      <machine maxCpus='2'>smdkc210</machine>
      <machine maxCpus='1'>collie</machine>
      <machine maxCpus='1'>imx25-pdk</machine>
      <machine maxCpus='1'>spitz</machine>
      <machine maxCpus='4'>realview-pbx-a9</machine>
      <machine maxCpus='1'>realview-eb</machine>
      <machine maxCpus='1'>versatilepb</machine>
      <machine maxCpus='1'>realview-pb-a8</machine>
      <machine maxCpus='1'>musicpal</machine>
      <machine maxCpus='1'>z2</machine>
      <machine maxCpus='1'>akita</machine>
      <machine maxCpus='255'>virt-2.7</machine>
      <machine maxCpus='1'>kzm</machine>
      <machine maxCpus='255'>virt-2.8</machine>
      <machine canonical='virt-2.8' maxCpus='255'>virt</machine>
      <machine maxCpus='4'>realview-eb-mpcore</machine>
      <machine maxCpus='1'>sx1</machine>
      <machine maxCpus='1'>sx1-v1</machine>
      <machine maxCpus='255'>virt-2.6</machine>
      <machine maxCpus='1'>cubieboard</machine>
      <machine maxCpus='4'>highbank</machine>
      <machine maxCpus='4'>raspi2</machine>
      <machine maxCpus='1'>netduino2</machine>
      <machine maxCpus='1'>terrier</machine>
      <machine maxCpus='1'>n810</machine>
      <machine maxCpus='1'>mainstone</machine>
      <machine maxCpus='1'>palmetto-bmc</machine>
      <machine maxCpus='4'>sabrelite</machine>
      <machine maxCpus='4'>midway</machine>
      <machine maxCpus='1'>cheetah</machine>
      <machine maxCpus='1'>tosa</machine>
      <machine maxCpus='1'>borzoi</machine>
      <machine maxCpus='1'>versatileab</machine>
      <machine maxCpus='1'>lm3s6965evb</machine>
      <machine maxCpus='1'>n800</machine>
      <machine maxCpus='1'>connex</machine>
      <machine maxCpus='1'>xilinx-zynq-a9</machine>
      <machine maxCpus='1'>xlnx-ep108</machine>
      <machine maxCpus='4'>vexpress-a9</machine>
      <machine maxCpus='4'>vexpress-a15</machine>
      <machine maxCpus='1'>xlnx-zcu102</machine>
      <machine maxCpus='1'>canon-a1100</machine>
      <machine maxCpus='1'>lm3s811evb</machine>
      <domain type='qemu'/>
      <domain type='kvm'>
        <emulator>/usr/bin/kvm</emulator>
        <machine maxCpus='1'>integratorcp</machine>
        <machine maxCpus='2'>nuri</machine>
        <machine maxCpus='1'>verdex</machine>
        <machine maxCpus='1'>ast2500-evb</machine>
        <machine maxCpus='2'>smdkc210</machine>
        <machine maxCpus='1'>collie</machine>
        <machine maxCpus='1'>imx25-pdk</machine>
        <machine maxCpus='1'>spitz</machine>
        <machine maxCpus='4'>realview-pbx-a9</machine>
        <machine maxCpus='1'>realview-eb</machine>
        <machine maxCpus='1'>versatilepb</machine>
        <machine maxCpus='1'>realview-pb-a8</machine>
        <machine maxCpus='1'>musicpal</machine>
        <machine maxCpus='1'>z2</machine>
        <machine maxCpus='1'>akita</machine>
        <machine maxCpus='255'>virt-2.7</machine>
        <machine maxCpus='1'>kzm</machine>
        <machine maxCpus='255'>virt-2.8</machine>
        <machine canonical='virt-2.8' maxCpus='255'>virt</machine>
        <machine maxCpus='4'>realview-eb-mpcore</machine>
        <machine maxCpus='1'>sx1</machine>
        <machine maxCpus='1'>sx1-v1</machine>
        <machine maxCpus='255'>virt-2.6</machine>
        <machine maxCpus='1'>cubieboard</machine>
        <machine maxCpus='4'>highbank</machine>
        <machine maxCpus='4'>raspi2</machine>
        <machine maxCpus='1'>netduino2</machine>
        <machine maxCpus='1'>terrier</machine>
        <machine maxCpus='1'>n810</machine>
        <machine maxCpus='1'>mainstone</machine>
        <machine maxCpus='1'>palmetto-bmc</machine>
        <machine maxCpus='4'>sabrelite</machine>
        <machine maxCpus='4'>midway</machine>
        <machine maxCpus='1'>cheetah</machine>
        <machine maxCpus='1'>tosa</machine>
        <machine maxCpus='1'>borzoi</machine>
        <machine maxCpus='1'>versatileab</machine>
        <machine maxCpus='1'>lm3s6965evb</machine>
        <machine maxCpus='1'>n800</machine>
        <machine maxCpus='1'>connex</machine>
        <machine maxCpus='1'>xilinx-zynq-a9</machine>
        <machine maxCpus='1'>xlnx-ep108</machine>
        <machine maxCpus='4'>vexpress-a9</machine>
        <machine maxCpus='4'>vexpress-a15</machine>
        <machine maxCpus='1'>xlnx-zcu102</machine>
        <machine maxCpus='1'>canon-a1100</machine>
        <machine maxCpus='1'>lm3s811evb</machine>
      </domain>
    </arch>
    <features>
      <cpuselection/>
      <deviceboot/>
      <disksnapshot default='on' toggle='no'/>
    </features>
  </guest>

</capabilities>