My customer has already purchased 30 Windows 8.1 Retail licenses (the Basic edition, as in "non-Pro") and installed 30 virtual Windows 8.1 guest computers hosted on a Linux Qemu/KVM server.

The primary use for the whole setup is serving an old non-terminal server capable E-Examinations-Software running in the guests to Zero clients.

These Linux-based Thin/Zero Clients are running a VNC or SPICE client which connect to the VNC or SPICE listening port of the KVM hypervisor guest instances.

Now there has been some discussion regarding the licensing compliance of this whole setup.

I know that the Windows 8.1 EULA (contrary to Windows 7 Home Editions) explicitly allows the installation on a virtualized computer (Additional Terms - 1.e) but it does not mention anything regarding a Remote Desktop Server side, obviously because RDP access is not possible in non-Pro Windows Editions.

Since the VNC or SPICE "Remote Desktop Connection" is not performed to the guest but instead to the Hypervisor software we're pretty confident that no additional RDS CALs or VDA/SA subscriptions whatsoever are necessary. 

I'd be grateful for any confirmation or comments if this setup is fine from Microsoft's licensing point of view !

Hi vfocker,

For the liscense issue, it is recommended to make a phone call directly.
Contact Us
https://www.microsoft.com/Licensing/servicecenter/Help/Contact.aspx

Best regards

Seriously? You're redirecting me to the "Microsoft Volume Licensing Service Center" ?

Hi vfocker,

Considering you have 30 machines and it should be a small business environment. We could try to ask for support here.

Best regards