Yesterday Citrix released under GPL2 open source license a new component of its Project Satori, the software stack for paravirtualized Linux guest OSes that run on Microsoft Hyper-V.
The core of this software has been already released by Microsoft under the name of Linux Integration Components in September 2008.
It included the hypercall adapter for Hyper-V, the optimized disc driver (called StorVSC) and the optimized network driver (called NetVSC).
The package missed an optimized mouse driver (called InputVSC) that implies poor performance when the Hyper-V console is remotely accessed and the use tries to interact with the Guest OS from inside it.
The InputVSC driver is now available here.