Add SPICE support by installing qemu-system-modules-spice

[slawomir-andreasik]

Summary

This PR adds the qemu-system-modules-spice package to the Docker image, enabling SPICE protocol support for enhanced VM interaction capabilities.

Problem

Currently, users attempting to use SPICE with the container encounter errors:

ERROR: qemu-system-x86_64: -spice port=5930,addr=0.0.0.0,disable-ticketing: There is no option group 'spice'
qemu-system-x86_64: -spice port=5930,addr=0.0.0.0,disable-ticketing: Perhaps you want to install qemu-system-modules-spice package?

This limitation blocks several important use cases:

• Audio device passthrough - Users cannot pass through microphones or speakers to the Windows VM ([Feature]: Spice support #1478)
• GPU passthrough with proper input handling - SPICE is essential for keyboard and mouse functionality when using GPU passthrough (GPU Passthrough #22)
• Looking Glass integration - SPICE is required for proper operation of Looking Glass, which provides low-latency display for GPU-passthrough scenarios

Solution

The fix is straightforward: install the qemu-system-modules-spice package alongside other dependencies. This single-line change enables QEMU's -spice option without affecting existing functionality.

Use Cases

This change enables users to:

1. Pass through audio devices - Access real microphone/speaker hardware in Windows (not just RDP's remote audio)
2. Use GPU passthrough effectively - Combined with Looking Glass for near-native graphics performance with proper input device handling
3. Connect via SPICE protocol - Alternative to RDP with better device support

Testing

The SPICE module has been successfully used in modified builds of this image, as demonstrated in community implementations: https://www.youtube.com/watch?v=koNym2aW7Js

Impact

• Backward compatible - Simply adds an optional package; existing functionality unchanged
• Small footprint - Minimal increase in image size

[kroese]

Thanks! But this should be submitted to the base project: https://github.com/qemus/qemu instead.

[slawomir-andreasik]

Thanks for the feedback! You're right - this belongs at the base layer.

I've submitted the change to qemus/qemu instead: qemus/qemu#978

The PR includes detailed context on why SPICE is essential for GPU passthrough + Looking Glass gaming setups (as documented in the official Looking Glass installation guide).

Closing this PR in favor of the upstream change.

[slawomir-andreasik]

Moved to upstream: qemus/qemu#978