My favorite virtual memory trick, in the context of operating system kernel development, is to make one of the top-level page table entries point to the physical location of the page table itself. This makes it easy to manipulate the page table in the virtual address space, without turning off paging. Some articles on the topic:

* http://wiki.osdev.org/Page_Tables#Recursive_mapping

* https://medium.com/@connorstack/recursive-page-tables-ad1e03...