1. A method for data storage, comprising: in a system that includes a host having a host memory and a memory controller that is separate from the host and stores data for the host in a non-volatile memory including multiple analog memory cells, storing in the host memory information items relating to respective groups of the analog memory cells of the non-volatile memory; receiving from the host a command that causes the memory controller to access a given group of the analog memory cells; and in response to the command, retrieving from the host memory by the memory controller a respective information item relating to the given group of the analog memory cells, and accessing the given group of the analog memory cells using the retrieved information item.