Good to know the difference between upstream Istio and Openshift Service Mesh as we embrace Service Mesh for applications. Openshift Service Mesh is based on upstream Maistra Service Mesh and you can read more about the difference here: https://maistra.io/docs/ossm-vs-community.html#ossm-vs-istio_ossm-vs-istio
As there is not much detailed documentation on ServiceMeshControlPlane configs, it is useful to look at the source code of the SM operator if you want to dig deep: https://github.com/maistra/istio-operator
Another overview: https://medium.com/@tamber/service-mesh-101-istio-rh-ocp-service-mesh-overview-fc4c4b05da1d
RH documentation: https://access.redhat.com/documentation/en-us/openshift_container_platform/4.6/html-single/service_mesh/index