GPU DDK - Unvalidated sHWPerfCtlDMABuf GPU-VA, DMA-write into FW privdata via MMU ctx 0

Kernel software installed and running inside a Guest VM may post improper commands to the GPU Firmware to trigger a write of data outside the Guest's virtualised GPU memory.

Software installed and run under a Guest VM can send commands to the GPU which result in out of bounds memory accesses. These can be used to escalate privileges.