Microsoft has published pages that list the hotfixes that have been published for Windows Server 2012 R2 Hyper-V and Failover Clustering. You can find them here:
- Hyper-V: Update List for Windows Server 2012 R2
- Recommended hotfixes and updates for Windows Server 2012 R2-based failover clusters
- List of currently available hotfixes for the File Services technologies in Windows Server 2012 R2
Make sure you wait a month before deploying (let someone else do the testing for you) and then use tools like Cluster Aware Updating (CAU) do the heavy lifting.
EDIT: I just added the link to the updates for file services. You’ll want those if implementing SMB 3.0 storage. You’ll find the updates for R2 on the bottom of the page (shared with WS2012).