Using a monitor with a desktop and laptop

What i want to do is use my monitor with both my desktop and laptop. the monitor is a 22″ hp with dvi and vga in. what i was going to do was use my KVM switch with it but if i do that then i loose the DVI quality from my desktop. i was wondering if i plugged both dvi and vga into the back of the monitor which one would it display, the DVI or VGA.