The new features and enhancements in Release 3.1.1 include:
Support for Storport miniport driver, which delivers improved performance compared to SCSI port driver.
For features introduced in the previous 2.0 release, see the Oracle VM Windows Paravirtual (PV) Drivers 2.0: New Features whitepaper at: http://www.oracle.com/us/technologies/virtualization/oraclevm/winpv20-newfeatures-wp-080929.pdf