You may have noticed if you are running QEMU/KVMmanually that in Windows the the position of the physical mouse does not match where the mouse is positioned within Windows.
There is an easy command to pass to qemu-kvm or qemu-system (whatever you call your binary):
-usbdevice tablet
The above flag will fix your mouse pointing problems whether you are running Windows 95, 98, NT, XP 2000, 2003, Vista, 7, 8 10 or Server 2000, 2003, 2008, 2012, 2016 or 2........