Maybe dumb question, but how do you serve multiple users with the full context length?

After experimenting with llama.cpp, I'm wondering a thing.

Let's say we have an LLM with a context size of 128k. Now let's say we want have up to 8 parallel users, and we want to provide each client with the full context capabilities.

With llama.cpp, how does that work? AFAIK it only allows sharing the 128k between users, but not actually providing 128k per user.

Is there something I'm missing? Thanks