Host and accelerator devices can be coupled using various interfaces, such as Compute Express Link (CXL). In an example, user applications can have protected access to a shared set of control parameters for different queues. A protocol can allow an application to use a unique memory page at the accelerator device through which the application can access control parameters, such as can be used to control memory-based communication queues or other queues. In an example, there can be multiple sets of control parameters in a single memory page. The protocol can allow views of the single memory page from respective different application processes. In an example, the protocol can include or use an access check to detect and handle unauthorized accesses to particular parameters.