I have a question regarding the best way to temporally disable write-access on memory pages. Suppose in the user-space, there are two processes: initial user-space process and process A, which is created by the initial process. Process A has its own virtual memory space.

Now we want to find a way to enforce the memory inside process A to be temporally R/O to process A (since we want to have the initial process compute a function on that memory snapshot.) Currently, what we are doing now is to lock all memory pages of process A by calling the "remap" function inside the initial process. 

But then we realize that doing that does not help much. Since process A owns capabilities to its memory pages, process A also can call "remap" function to unlock the locked memory pages (please correct me if it's wrong). This will cause the memory to be inconsistent when computing a function on that memory.

My question is is there anyway to enforce how a page locking (make it R/O) works in seL4 so that ONLY the entity that locked the page can unlock it? For example, in this case, we want to make sure that only the initial process can unlock the pages that he locked earlier.

Thank you,

Oak

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