OpenAMP is a "framework" (whatever that means) that uses libmetal, which is a software library (that is unambiguous to me)
Looking at the few and meagre examples around, it looks to me that libmetal is good for unsupervised AMP/SMP but openAMP is for supervised xMP (master/ slave or whatever one should call them to be politically correct).
So, is OpenAMP a wrapper of libmetal? I mean, can I use either or is there any extra feature in openAMP not available with libmetal?
Sorry if you already knew this, but just in case you did not I thought I would try to be helpful and suggest taking a look at UG1186. It is in docnav or can be found via duckduckgo.com search engine (or other more evil search engines).