EFI_MEMORY_ATTRIBUTE_PROTOCOL support for X64 just landed in edk2 git repository.
Expect this showing up in firmware (both OVMF and physical hardware) later this year.

Breaks booting with grub pretty much everywhere (rhel-10, rhel-9, fedora).

Steps to reproduce

(1) update edk2 to a build with EFI_MEMORY_ATTRIBUTE_PROTOCOL included.
(2) try boot any rhel-ish guest in default configuration.

Expected results

VM boots fine.

Actual results

VM triggers a page fault.

Additional info

firmware -> shim -> grub -> kernel: fails
firmware -> grub -> kernel: fails.
firmware -> shim -> kernel: works.