Document that SPICE clipboard on Windows ARM requires virtio-ramfb (display backend dependency)

[tom-un]

Summary

Clipboard sharing via SPICE on Windows ARM VMs depends on the selected display backend, but this dependency is not documented and is non-obvious.

Environment

• UTM version: 4.7.5 (118)
• macOS: 26.4.1 (25E253)
• Guest: Windows 11 ARM
• VM type: Virtualize

Observations

With SPICE guest tools installed (spice-vdagent running):

Clipboard behavior varies depending on the display device:

Display Device	Clipboard
virtio-ramfb	✅ Works
virtio-ramfb-gl	❌ Does not work
virtio-gpu / gpu-gl	❌ Does not work

Key Insight

Clipboard integration requires:

1. SPICE guest agent (installed and running)
2. A SPICE-compatible display backend

Using accelerated/GL display modes appears to bypass or disable the SPICE channel required for clipboard integration, even though the agent is running and UTM UI indicates clipboard sharing is enabled.

Why this is confusing

• Clipboard sharing can be enabled in UTM settings regardless of display backend
• SPICE services appear healthy inside the guest
• Failure mode is silent (no error, clipboard just doesn't work)

This makes it difficult to diagnose and can lead to incorrect assumptions that SPICE is unsupported on Windows ARM.

Suggestion

Add documentation (and possibly UI hints) clarifying:

• Clipboard sharing requires both:
  • SPICE guest agent
  • A SPICE-compatible display backend (e.g. virtio-ramfb)
• GPU/GL display modes may disable clipboard integration

Optional: warn in UI when clipboard sharing is enabled with a non-SPICE-compatible display.

Additional note

This behavior is reproducible and switching to virtio-ramfb immediately restores clipboard functionality.

Working settings: