Description of problem:
Using virt-manager to creating a new VM with Windows 8.1 as guest defaults to rtl8139 as the default network adapter. If you choose to customize the configuration on the last page of the 'New VM' wizard and select 'UEFI x86_64' as firmware, the VM will never boot, not even to an EFI shell. Using virtio as NIC instead works fine. See also additional info.

Version-Release number of selected component (if applicable):
libvirt: 1.2.18.2
virt-manager: 1.3.2

How reproducible:


Steps to Reproduce:
0. Get edk2 firmware on fedora: https://fedoraproject.org/wiki/Using_UEFI_with_QEMU#Installing_.27UEFI_for_QEMU.27_nightly_builds
1. Create new VM with virt-manager
2. Select Windows 8.1 as OS version
3. When you get to the final page of the 'New VM' wizard, follow this paragraph: https://fedoraproject.org/wiki/Using_UEFI_with_QEMU#virt-manager 

Actual results:
The VM is stuck with a white solid bar just after start up. You can get into the boot menu but even starting an EFI shell from there will not work.

Expected results:
Boot up something...

Additional info:
https://fedoraproject.org/wiki/Using_UEFI_with_QEMU
If you choose virtio or e1000 as network adapter, the VM boots fine. I understand that this is not a supported configuration since it does not ship with fedora but an external repository is needed, if it's not possible to change the default network adapter used with windows 8.1 then add a warning on the fedoraproject page I linked, this thing does not throw any error at you, it has been really a matter of luck finding that the issue was the network adapter.