Allow guest OS to access graphics adapter directly-Collection of common programming errors

I/O hardware Virtualization especially for graphics card is made using technology called IOMMU. AMD has published a specification for IOMMU technology in the HyperTransport architecture. Intel has published a specification for IOMMU technology as Virtualization Technology for Directed I/O, abbreviated VT-d.

With virtualization, guest operating systems can use hardware that is not specifically made for virtualization. An example for IOMMU is Graphics Address Remapping Table (GART) used by AGP and PCI Express graphics cards. Higher performance hardware such as graphics cards use DMA to access memory directly; in a virtual environment all the memory addresses are remapped by the virtual machine software, which causes DMA devices to fail. The IOMMU handles this remapping, allowing for the native device drivers to be used in a guest operating system.

Most of the Virtualization softwares supports hardware acceleration for OpenGL and some of them provides experimental Direct3D acceleration such as VMWare. Products from VMware, Citrix and VirtualBox etc. provides hardware accelaration