Description of problem:

VM can start with mac address as "00:00:00:00:00:00"

Version-Release number of selected component (if applicable):

libvirt-9.5.0-3.el9.x86_64

How reproducible:

100%

Steps to Reproduce:

1. Prepare a vm xml with interface set with mac address as "00:00:00:00:00:00";

   # cat rhel.xml | grep /interface -B5
       <interface type='network'>
         <mac address='00:00:00:00:00:00'/>
         <source network='default'/>
         <model type='virtio'/>
         <address type='pci' domain='0x0000' bus='0x07' slot='0x00' function='0x0'/>
       </interface>
   
   # Define and start the vm, it starts successfully;
   # virsh define rhel.xml
   Domain 'rhel' defined from rhel.xml
   # virsh start rhel
   Domain 'rhel' started
   

2. Check the mac address on vm, it is a random mac; but the live xml keeps as "00:00:00:00:00:00";
   The network works well on the guest.

   [root@guest]# ip addr show enp7s0
   2: enp7s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
       link/ether 52:54:00:12:34:56 brd ff:ff:ff:ff:ff:ff
       inet 192.168.122.76/24 brd 192.168.122.255 scope global dynamic noprefixroute enp7s0
          valid_lft 3586sec preferred_lft 3586sec
       inet6 fe80::3910:d1e9:6a5c:7906/64 scope link noprefixroute
          valid_lft forever preferred_lft forever
   
   [root@host]# virsh domiflist rhel
    Interface   Type      Source    Model    MAC
   -------------------------------------------------------------
    vnet1       network   default   virtio   00:00:00:00:00:00
   
   [root@host]# ip l show vnet1
   56: vnet1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master virbr0 state UNKNOWN mode DEFAULT group default qlen 1000
       link/ether fe:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
   

Actual results:

VM can start with a mac address as "00:00:00:00:00:00", which causes the mac address from "virsh domiflist" will be inconsistent with the mac address in the guest OS.

Expected results:

The vm can not start if it set with an invalid mac address

Additional info: