Guest-memfd was originally used implicitly only in CoCo environment to represent private pages of a CoCo VM. This story tracks the progress of having guest-memfd to be in-place memory backends for QEMU just like other kinds of common memory backends, without CoCo context.  

More information can be found here:

https://lore.kernel.org/all/20251023185913.2923322-1-peterx@redhat.com/