Hi All
As describe here: 
https://forums.opensuse.org/showthread.php/531290-KVM-Qemu-Mouse-Pointer/page1

In short:
I have a openSUSE 42.1 installed as host server with KVM and Qemu, the guest VM 
on this host is the new opensuse LEAP 15, the installation goes fine but after
the login screen the mouse pointer disappear and seems to be that not exist for
the guest OS (leap 15)

After some test i have discover that the mouse problem is present only when
desktop environment is KDE Plasma and KDE Plasma Wayland.

I don't tried gnome or others DE.

Thanks 
Fabio