gnif/LookingGlass
LookingGlass
LookingGlass is a low-latency display mirror and frame relay system designed to transfer video frames from a KVM guest operating system to a host window in real time. It functions as a specialized bridge that allows for the viewing of virtual machine outputs using hardware passthrough to minimize lag.
The system utilizes VGA PCI passthrough to relay frames from a guest virtual machine to a local display window. This approach focuses on high-performance display mirroring, providing a way to view guest displays on a host machine without using traditional network protocols.
The implementation relies on a shared-memory framebuffer and direct memory access to move pixel data across hardware boundaries. These mechanisms enable user-space frame rendering by capturing the mapped guest framebuffer and rendering it directly into a host application window.
Features
- Frame Relays - A low latency system for relaying frames from a KVM guest with VGA PCI passthrough to a host window.
- Virtual Display Mirroring - Relays frames from a virtual machine guest to a host window using low latency hardware passthrough.
- VM Display Streaming - Streams a virtual machine screen to a host window with minimal lag using KVM FrameRelay.
- Guest-Component Shared Memory - Utilizes a memory region accessible by both the guest and host to transfer video data without copying.
- Hardware Passthrough Utilities - Provides a high performance display utility for viewing virtual machine outputs using hardware passthrough.
- Local Guest Display Viewers - Provides a way to view a virtual machine guest display on the host without using high-overhead network protocols.
- PCI Device Passthroughs - Employs VGA PCI passthrough to relay frames from a virtual machine guest to a local display window.
- Frame Relay Mechanisms - Implements a specialized relay that moves raw display frames from a KVM guest to a host window.
- VM Frame Buffering - Implements high-performance memory mapping and buffering to transfer video frames from a guest to a host display.
- Framebuffer Renderers - Captures the mapped guest framebuffer and renders it directly into a host application window.
- Low-Latency Pixel Transfers - Uses direct memory access to move pixel data across hardware boundaries to minimize CPU overhead and lag.
- KVM Interactive Optimizations - Improves the interactive experience of guest machines by mirroring display output to the host OS.
