Como ativar a rede para o xen guest

Question

Eu tenho um muito estranho. A configuração é um host do Ubuntu 16.04, com o xen instalado. Estou usando o virt-manager no meu mac para gerenciar as máquinas. Eu adicionei uma rede em ponte, então tentei adicionar uma máquina virtual. Quando eu configurar a configuração da máquina, selecione a rede em ponte e clique em Concluir. Recebo o erro: Unable to complete install: 'internal error: libxenlight failed to create new domain 'mattermost''

O que estou perdendo?

Eu tenho outra máquina, com configuração e configuração idênticas, e os convidados estão bem e trabalham sem nenhuma configuração.

Algumas exportações:

sudo lshw -class network
*-network
   description: Ethernet interface
   product: NetLink BCM57788 Gigabit Ethernet PCIe
   vendor: Broadcom Corporation
   physical id: 0
   bus info: pci@0000:03:00.0
   logical name: enp3s0
   version: 01
   serial: 78:2b:cb:9a:04:9d
   size: 1Gbit/s
   capacity: 1Gbit/s
   width: 64 bits
   clock: 33MHz
   capabilities: pm msi pciexpress bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation
   configuration: autonegotiation=on broadcast=yes driver=tg3 driverversion=3.137 duplex=full firmware=sb ip=10.0.1.172 latency=0 link=yes multicast=yes port=MII speed=1Gbit/s
   resources: irq:91 memory:fe500000-fe50ffff
*-network DISABLED
   description: Ethernet interface
   physical id: 1
   logical name: virbr0-nic
   serial: 52:54:00:ef:54:1f
   size: 10Mbit/s
   capabilities: ethernet physical
   configuration: autonegotiation=off broadcast=yes driver=tun driverversion=1.6 duplex=full link=no multicast=yes port=twisted pair speed=10Mbit/s


gyula@arse_end_of_the_network:~$ cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

auto enp3s0
iface enp3s0 inet dhcp

iface xenbr0 inet dhcp
  bridge_ports enp3s0


gyula@arse_end_of_the_network:~$ ifconfig -a
enp3s0    Link encap:Ethernet  HWaddr 78:2b:cb:9a:04:9d
      inet addr:10.0.1.172  Bcast:10.0.1.255  Mask:255.255.255.0
      inet6 addr: fe80::7a2b:cbff:fe9a:49d/64 Scope:Link
      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
      RX packets:39905 errors:0 dropped:11 overruns:0 frame:0
      TX packets:45206 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1000
      RX bytes:5644162 (5.6 MB)  TX bytes:45211362 (45.2 MB)
      Interrupt:19

lo        Link encap:Local Loopback
      inet addr:127.0.0.1  Mask:255.0.0.0
      inet6 addr: ::1/128 Scope:Host
      UP LOOPBACK RUNNING  MTU:65536  Metric:1
      RX packets:64987 errors:0 dropped:0 overruns:0 frame:0
      TX packets:64987 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1
      RX bytes:84775586 (84.7 MB)  TX bytes:84775586 (84.7 MB)

virbr0    Link encap:Ethernet  HWaddr 52:54:00:ef:54:1f
      inet addr:192.168.122.1  Bcast:192.168.122.255          
Mask:255.255.255.0
      UP BROADCAST MULTICAST  MTU:1500  Metric:1
      RX packets:0 errors:0 dropped:0 overruns:0 frame:0
      TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1000
      RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

virbr0-nic Link encap:Ethernet  HWaddr 52:54:00:ef:54:1f
      BROADCAST MULTICAST  MTU:1500  Metric:1
      RX packets:0 errors:0 dropped:0 overruns:0 frame:0
      TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1000
      RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)