GPU virtualization has become an increasingly important requirement for client virtualization and cloud. Significant challenges exists realizing the multiplexing of graphics, media and compute workloads from multiple VMs and achieving the goals of being fully functional, high performance and secure. In this presentation, we will first review existing graphics virtualization technologies, and then introduce how XenGT - an open source solution from Intel - approaches differently. Broad functionality and good performance is achieved by accelerating the native OS graphics stack in each VM with minimum hypervisor intervention. A software mediator ensures the secure multiplexing of workloads from the multiple VMs by managing the scheduling of VMs on the GPU and controlling access to privileged resources and operations.