On 12/17/19 5:52 AM, abhishek jain wrote: You aren't using libvirt, you are running the qemu-system-x86_64 command directly. Since you're not actually using libvirt in this example, this isn't the best place to ask, but based on the error message, I'd say that you are running qemu-system-x86_64 as an unprivileged user, and qemu is trying to open the device /dev/vhost-net, but can't due to the lack of privileges. If you used a libvirt-based management application to start your qemu (e.g. virsh, virt-manager, cockpit, ovirt, openstack) then they would call the libvirtd daemon, which is running with full root privileges and would open the vhost-net device, then pass that to an unprivileged qemu. If you really must continue using qemu directly, then you'll need to either stop using vhost=on, or run qemu as root (and take all the security risks associated with that).