I have a blogged about this before – but we maintain a list of all updates / hotfixes that have been released for Hyper-V on Windows Server 2008 R2. We update this list regularly – and have just rolled out the latest updates. You can review the list here:
You should make sure to check this article regularly as we are always updating it.
We also have a similar list that we provide for Hyper-V on Windows Server 2008: