Shared clipboard support between Linux host and Windows 10 guest

[Laurent Halter]

Hi everyone,

My first post here :)

I'm currently trying to have shared clipboard support between a Linux host and a Windows 10 guest.

It works perfectly if I use -display spice-app. Here are my working arguments to QEMU:

  -name $WINDOW_NAME \
  -m 4G \
  -smp $(($(nproc) / 3)) \
  -hda "$QCOW2_FILE" \
# -incoming "exec: cat memsnapshot"
# -incoming "exec: gzip -c -d memsnapshot.gz"
  -cpu host \
  -enable-kvm \
  -usb -device usb-tablet \
  -audiodev pa,id=pa0,out.stream-name=qemu-audio \
  -device ich9-intel-hda \
  -device hda-output,audiodev=pa0 \
  -boot c \
  -device virtio-serial,packed=on,ioeventfd=on \
  -chardev spicevmc,id=vdagent,name=vdagent \
  -device virtserialport,chardev=vdagent,name=com.redhat.spice.0 \
  -display spice-app \
#  -display gtk \
  -device usb-ehci,id=ehci \
  -device qemu-xhci,id=xhci

But... I'd prefer to use the Gtk display, for several reasons:

• The mouse cursor is much smoother (looks like the real "hardware" cursor is used ?).
• When I close the QEMU window, the QEMU process is also ended, as when with the spice-app display, QEMU continues running, and I have to kill it manually every time.
  
• I do not really need the features offered by spice-app / virt-viewer, and I'm quite used to the existing keyboard shortcuts of Gtk.

I've tried everything to make the above parameters work with Gtk display:

• Installing several versions of virtio drivers, SPICE VDAgent and QEMU GUEST Agent on my Windows guest.
• Installing several versions of  spice-vdagent and spice-vdagentd  on my Linux host.
• Checking all services are running.
• Modifying QEMU's arguments.
  

...and never had any clipboard communication (in any direction).

I think my parameters (exposed above) are not so bad as they do work with "-display spice-app".

So far, my guess is that spice-app / virt-viewer are doing some extra or different things compared to spice-vdagent ?

Could you guys confirm me that this approach (shared clipboard without -display spice-app) should work  ?

If yes, any idea of what might go wrong here ?

I'm using QEMU version 8.2.2 on Ubuntu 24.04, and my Windows 10 installation is quite standard.

Thanks in advance for your answers !

Laurent