host_server.pemfile is the https certificate for the attestation server. This is used to securely communicate with the untrusted attestation server, which is used to get the SGX quote. In production, you should generate this certificate yourself and put it in inference server. To do this, read the next sections.
policy.tomlfile is used to specify which enclave should be accepted by the client. It basically contains the hash of the server binary, and the SGX flags the server should be run with. The client uses it to validate the quote sent by the server.
-v $(pwd)/tls:/root/tlsallows you to mount your own TLS certificate to the Docker Image.