|There is a type of KVM switch that allows you to have more than one keyboard, monitor, and mouse connected to a single computer. Something like that would work for your situation.|
However, I'm not sure what the maximum length you can do K/B, mouse and monitor is. You would need to research that first and the figure out if you could located your upstairs workstation within the maximum limit.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.