We need at least 1M of RAM to map the option ROM. Otherwise, we will
corrupt host memory or even crash:
$ qemu-system-x86_64 -nodefaults --enable-kvm -vnc :0 -m 640k
Segmentation fault (core dumped)
Reported-and-tested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>