Using Spice + QXL for a 16.04 guest running on a 16.04 KVM hypervisor. This was working normally until recently.
After the last reboot of the guest, resolution was set to 1024×768. When I try setting it back to 1680×1050 (or any resolution), the session freezes until the timeout reverts back to the previous resolution.
spice-vdagent and the xorg QXL driver are installed on the guest.
(edit: added additional info)
This allowed me to change the resolution, but is not persistent across reboots:
xrandr -s 1680x1050