If you run Red Hat Enterprise Linux (RHEL) as a guest OS on Hyper-V, you will be interested to know that Red Hat certifies Hyper-V as a supported hypervisor for running RHEL. The support services you get from Red Hat via your RHEL subscription are fully available when running RHEL in an on-premises installation of Hyper-V.
Microsoft recently obtained certification for the RHEL 7.0 release on Windows Server 2008 R2 Hyper-V, Windows Server 2012 Hyper-V, and Windows Server 2012 R2 Hyper-V. The 2012 R2 Hyper-V certification includes both Generation 1 and Generation 2 VMs.
Earlier versions of RHEL are also certified by Red Hat, including RHEL 5.9 and later, and RHEL 6.4 and later. Both the 32-bit and 64-bit versions are certified.