Hi,
I couldn't find any way to revoke access once granted via sigma0. Or for a L4 userland process to "put back" the memory it has previous requested access to.
Processes can unmap their memory themselves, or those inbetween. Just not sigma0 because that's not its task. io is handling everything non-ram for multiple clients etc. I'd think of the normal side as a device which has some (big) MMIO and handle it that way on the secure side. Why would you like to get rid of the memory again?
I thought if I had a process release its memory then another process could be granted it. And so I could map and then unmap for reach request. But it sounds like I should look into the io server a bit more, or re-read through how moe can configure things.
Thanks,