1. In a computing device executing a hypervisor hosting a trusted virtual machine and a non-trusted virtual machine, a method for preventing the non-trusted virtual machine from reading the graphical output of the trusted virtual machine, comprising: receiving, by a graphics manager executed by a processor of a computing device, a request from a trusted virtual machine executed by the computing device to render graphical data using a graphics processing unit of the computing device; assigning, by the graphics manager to the trusted virtual machine, a secure section of a memory of the graphics processing unit; rendering, by the graphics manager, graphics from the trusted virtual machine graphical data to the secure section of the graphics processing unit memory; receiving, by the graphics manager, a request from a non-trusted virtual machine executed by the computing device to read graphics rendered from the trusted virtual machine graphical data and stored in the secure section of the graphics processing unit memory; and preventing, by the graphics manager, the non-trusted virtual machine from reading the trusted virtual machine rendered graphics stored in the secure section of the graphics processing unit memory.