I'm also having the exact same issue. Seems to be related to this bug: https://bugs.launchpad.net/ubuntu/+source/swtpm/+bug/1989100
I tried adding /run/libvirt/qemu/swtpm/*.pid rwk, to /etc/apparmor.d/local/usr.bin.swtpm as mentioned in the bug report but that didn't seem to fix the issue for...