Created attachment 616975 [details] Fixes the problem With the latest qemu, if you change resolution in a guest that uses an older (v3) qxl driver then the guest qxl driver "hangs", meaning you can't further access the VM. The reason for this is a bug in the qxl part of qemu when verifying qxl driver calls. See attached patch for details.
qemu-1.2.0-10.fc18 has been submitted as an update for Fedora 18. https://admin.fedoraproject.org/updates/qemu-1.2.0-10.fc18
qemu-1.2.0-10.fc18 has been pushed to the Fedora 18 stable repository. If problems still persist, please make note of it in this bug report.