If, like me, you have been running virt-manager over an SSH tunnel, and are getting problems with the keyboard / key mappings, then you may be able to fix them by changing the keyboard settings in the virtual machines configuration.
1) Click the details button in the virtual machines virt-manager window.
2) Navigate to the Display VNC option in the left hand menu.
3) You should now see a Keymap drop down box. Select the correct Keymap that matches your keyboard, in my case it was en-gb.
4) Click Apply.
Good luck, it worked for me!