I don’t know whether it will help. But you could try to uninstall “spice-vdagent” in the VM. And you will have to then taboo it (lock it) to prevent future reinstall.
As far as I know, spice-vdagent attempts to synchronize the cut/paste buffer between the host and the VM.
Since I made the change suggested above, I have experienced no issues with cutting and pasting operations confined to the host or confined to the guest.
I understand that the package which I disabled was intended to help guest<->host copy paste. I can live with out that for the time being.
Thanks for reporting back. And I’m glad that helped.
I do still use spice-vdagent, and I haven’t noticed problems. But it occurs to me that when running KDE in a KDM guest, I always disable the clipboard option to save clipboard contents on exit. It’s possible that is all that you really needed. Otherwise, when you login to KDE in the guest, it restores clipboard contents and shares that with the host.
I should add that the reason I disable saving clipboard, is that I don’t want it to ever save a password that I might happen to have selected.
Cleaning up old Forum threads while I’ve been gone,
Should be noted that the @OP never only described running libvirt and some GuestOS, but never mentioned what virtualization (eg KVM or Xen or something else).
Also was not clear whether the Guest properties were ever inspected for their settings which might be required to use the clipboard between Guest and Host, and supported behaviors.