If using VirtualBpx, see this serverfault question. Select Bridged Adapter in the Network→Adapter settings.
If using KVM, see this serverfault question and this unix.stackexchange question. This is significantly more complicated than the VirtualBox approach.
There is also this at golinuxcloud for using virt-manager. This refers to here for setting up a bridge. One suggestion there is nmtui which is a text UI for doing this sort of thing. Then with the bridge set up, you can add the bridge as a Virtual Network Adapter.
