There is a standard vhost-user JSON metadata format and file system location where vhost-user programs register themselves. kata-runtime does not use this information yet, relying on file system paths in configuration.toml instead.

It would be helpful to automatically detect the virtiofsd program using the standard vhost-user JSON metadata. This way Kata Containers and downstream packages don't need to hardcode file system paths. It will also be possible support multiple virtiofsd packages without local changes to configuration.toml (whichever virtiofsd implementation is installed will be used automatically).

The vhost-user JSON metadata format is documented here:
https://gitlab.com/qemu-project/qemu/-/blob/master/docs/interop/vhost-user.rst#id36

Libvirt implements the vhost-user JSON metadata format if you would like to look at an example implementation.