No reason to make this file executable.
-device scsi-hd,drive=hd,bootindex=1 \
-device vhost-vsock-pci,id=vhost-vsock-pci0,guest-cid=42 \
-smbios type=11,value=io.systemd.credential:vmm.notify_socket=vsock:2:1234 \
- -smbios type=11,value=io.systemd.credential.binary:tmpfiles.extra=$(echo "f~ /root/.ssh/authorized_keys 700 root root - $(ssh-add -L | base64 -w 0)" | base64 -w 0)
+ -smbios type=11,value=io.systemd.credential.binary:tmpfiles.extra=$(echo "f~ /root/.ssh/authorized_keys 600 root root - $(ssh-add -L | base64 -w 0)" | base64 -w 0)
```
A process on the host can listen for the notification, for example: