Virtio-nvgpu: Near-native Nvidia GPU access inside a KVM guest

Virtio-nvgpu enables near-native NVIDIA GPU access for KVM virtual machines by forwarding kernel driver calls between guests and the host, allowing unmodified NVIDIA drivers to run inside VMs. Testing on an RTX 3060 shows guests perform within 2% of bare metal with identical CPU costs, making it suitable for headless streaming applications where multiple VMs can share a single GPU card. The solution works by having the NVIDIA user-mode driver submit directly through shared memory, eliminating API-level translation overhead.