hi, all:

my xml  define interface as following:

    <interface type='ethernet'>
      <mac address='00:04:00:41:03:11'/>
      <model type='e1000'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </interface>

when run the command:

bash-4.1# virsh start root-vsys_v77
error: Failed to start domain root-vsys_v77
error: Unable to open /dev/net/tun, is tun module loaded?: No such file or directory

is my xml define error ? how can create my vm with nic driver e1000 ?

bash-4.1# libvirtd -v    ,yum install libvirt
2020-01-02 10:00:49.261+0000: 8349: info : libvirt version: 4.5.0, package: 23.el7 (CentOS BuildSystem <http://bugs.centos.org>, 2019-08-09-00:39:08, x86-02.bsys.centos.org)
2020-01-02 10:00:49.261+0000: 8349: info : hostname: NSG
2020-01-02 10:00:49.261+0000: 8349: warning : virGetHostnameImpl:719 : getaddrinfo failed for 'NSG': Name or service not known
2020-01-02 10:00:49.263+0000: 8349: info : libvirt version: 4.5.0, package: 23.el7 (CentOS BuildSystem <http://bugs.centos.org>, 2019-08-09-00:39:08, x86-02.bsys.centos.org)
2020-01-02 10:00:49.263+0000: 8349: info : hostname: NSG
2020-01-02 10:00:49.263+0000: 8349: info : virObjectNew:248 : OBJECT_NEW: obj=0x5605a6104de0 classname=virAccessManager
2020-01-02 10:00:49.263+0000: 8349: info : virObjectNew:248 : OBJECT_NEW: obj=0x5605a60f54e0 classname=virAccessManager

my emulator is qemu-3.0 ,i download qemu source code and compiled the emulator:

bash-4.1# /usr/local/bin/qemu-system-x86_64 --version
QEMU emulator version 3.0.0
Copyright (c) 2003-2017 Fabrice Bellard and the QEMU Project developers

thanks !