Microsoft has released a whitepaper titled: "Running SQL Server with Hyper-V Dynamic Memory". The paper which contains 39 pages covers how to configure Dynamic Memory, introduced with the release of Windows Server 2008 R2 Service Pack 1, when running SQL Server workloads on top of Hyper-V.
For testing the scenarios a two-node IBM x3850 X5 Server with Windows Server 2008 R2 failover cluster was used, with 32 physical processor cores and 128 GB of RAM. Storage was provided by a dedicated HDS AMS2500 storage system.