When using the Sun xVM hypervisor in a Solaris OS, fully virtualized guest domains are referred to as hardware-assisted virtual machines (HVMs). HVM + PVIO guests provide better performance through the use of PV drivers.
Releases starting with the Solaris 10 10/08 release are shipped with the Solaris PV drivers. A patch is available for Solaris 10 5/08.
For more information, see “Solaris 10 releases” in Guests That Are Known to Work in System Administration Guide: Virtualization Using the Solaris Operating System. This guide also discusses HVM-capable machines.