Very simple that the vif interface name is the base on the domain id:
# virsh list --all
Id Name State
0 Domain-0 running
12 xen_vm127 running
13 xen_vm126 running
14 xen_vm125 running
16 xen_vm123 running
17 xen_vm124 running
:~ # ip a
23: vif12.0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master br1 state UNKNOWN group default qlen 512
link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
24: vif13.0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master br1 state UNKNOWN group default qlen 512
link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
25: vif14.0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master br1 state UNKNOWN group default qlen 512
link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
27: vif16.0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master br1 state UNKNOWN group default qlen 512
link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
28: vif17.0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master br1 state UNKNOWN group default qlen 512
link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ffenter code here