Looking Glass Update! MASSIVE VFIO Breakthrough Incoming!

Technological concepts / main product

• Looking Glass project: software that enables Windows VMs running on Linux with full GPU acceleration via GPU pass-through (VFIO). It renders/streams frames back to the host to provide a near-native desktop experience.
• VFIO context: the speaker frames this as “10 years” of VFIO experience and positions Looking Glass as being “close to the promised land” for running a Windows VM on Linux with real hardware.

Performance results and setup approach

Host OS / VM stack

• Fresh Arch Linux install (host).
• Windows VM runs under Arch, reported as using 8 CPU cores.

Benchmark / gaming performance

• “Almost 200 FPS in Shadow of the Tomb Raider” (reported during the author’s Looking Glass update progress).
• ~120 FPS in updates on a Windows VM with eight cores.
• Example configuration: Windows VM with 8 cores, passing through a GeForce RTX 9070 Non-XT → reportedly ~179 FPS.

Resolution / display behavior

• The Looking Glass window can resize; resizing it resizes the guest Windows desktop to match the available pixel dimensions.
• Fullscreen support is mentioned as working.
  • Otherwise, the speaker uses Scroll Lock + F to toggle fullscreen behavior.
• Demonstrated “native resolution” behavior when not in fullscreen.

Hardware / platform configuration details (example build)

• Threadripper platform with many PCIe lanes:
  • ASRock TRX50 motherboard
  • 32-core Threadripper CPU
• Network: Mellanox ConnectX-5 25Gb NIC
• GPU pass-through:
  • Guest GPU: RTX 9070 Non-XT
  • Host GPU: an iGPU is implied; later explicitly mentions Sapphire 7600
• Storage:
  • Notes virtualized Windows storage performance; in one setup they did not even use a second NVMe for the Windows system.
• Case: Fractal North (referenced from a prior video)

Key feature / upcoming update: Indirect Display Driver (ID)

What it enables

• The Indirect Display Driver (ID) is described as a major upcoming Looking Glass change.
• It goes beyond classic GPU pass-through:
  • Can accelerate graphics using more than one CPU core when a hardware GPU is not passed through.
  • When configured via the Looking Glass indirect display device in a typical VM workflow (e.g., virt-manager), it can provide much better performance than SPICE/VNC.

Performance comparison

• Without a GPU acceleration driver:
  • Performance becomes janky/stuttery, potentially effectively single-core (default VGA behavior).
• With the indirect display driver:
  • Becomes “dramatically more usable” by distributing/using CPU horsepower across multiple cores.

When/where it’s recommended

• Suggested for HomeLab / Proxmox / similar scenarios, including environments where you can’t or don’t want to pass through hardware.

Caveat for enterprise VDI

Enterprise/VDI users may dislike it because it requires more CPU cores for acceleration. The speaker emphasizes that CPU-accelerated video acceleration/decompression still can’t match true hardware acceleration.

Stability / known limitations (GPU reset, Code 43)

Reset bug persists

• The speaker distinguishes issues: “Code 43” vs the “reset bug” (not necessarily the same).
• For the RTX 9070 setup:
  • Reset reliability isn’t fixed yet.
  • Workaround may be to power-cycle the machine if the GPU enters a bad state.

Code 43 during AMD driver install

• After installing AMD Adrenaline drivers on Arch:
  • On first boot, Code 43 is likely.
• Fix:
  • Shut down and reboot; the speaker claims this clears the GPU state.

Implication

• GPU passthrough may be bleeding-edge and may involve extra system configuration (e.g., MMU settings, resize bar, and virtualization manager configuration).

Automation / multi-VM GPU binding script

• Mentions a community script to safely bind/unbind the GPU.
• Use cases:
  • Multiple VMs needing GPU acceleration but not concurrently, such as:
    • a banking VM + gaming VM + another gaming VM (not simultaneous)
  • Proxmox-style workflow:
    • bind GPU to VM, unbind from host, etc.
• Note:
  • Works as long as the VM doesn’t crash or leave the GPU in an undefined state.

Tutorial / guide references (actionable pointers)

• The speaker plans to “show you how I did it” (Arch + Windows VM + Looking Glass setup).
• Mentions:
  • Forum threads for improvements and community experiences.
  • Checking the Looking Glass IO website/forum for the indirect display driver status (“coming soon”, not fully out yet).
  • Community packaging for Arch:
    • Install Git versions of Looking Glass and the indirect display driver for latest kernel compatibility.
  • Arch 2025 package tooling:
    • firmware- from Arch should be installed via yay/peru (phrased as “Linux firmware-get”, likely auto-generated).

Additional observations (Arch vs others)

• Claims Arch Linux (in 2025) is easier for VFIO/pass-through than:
  • Ubuntu 24.04
  • Debian
  • Proxmox
  • (based on the speaker’s setup friction experience)

Hardware/firmware fixes mentioned

• Firmware update matters:
  • The speaker claims a bug in Arch repository firmware caused visual artifacts (e.g., “one pixel column lines”).
  • Updating to firmware from linux-firmware-get resolves those issues.

Funding / project status

• Encourages donations to Looking Glass (citing “Jeff”).
• Claims Looking Glass is very near a 1.0 release, with improving stability/features.

Main speakers / sources

• Primary speaker: “Level1” (a community member/presenter), referenced explicitly and pointing viewers to the Level1 forums.
• Primary project referenced: LookingGlass (Looking Glass / Looking Glass IO website), including the Indirect Display Driver (ID) update.