ovmf: expose EFI prefixes and refactor qemu-vm with it

[RaitoBezarius]

Description of changes

In summary:

• EDK2 mkDerivation supports functional-style mkDerivation ;
• OVMF exposes EFI prefixes in passthru as firmware and variables
• virtualisation/qemu-vm uses it to pass them in the machinery, consolidating it ;
• adding myself as a maintainer of OVMF as I know well the ecosystem and am interested into maintaining it

How to test this? : nix-build nixos/tests/systemd-boot.nix -A basic, it if works, then QEMU's EFI still works fine. :)

It is pretty common to require the EFI firmware and variables of OVMF, this exposes it in passthru as suggested by @roberth on Matrix.
qemu-vm can be refactored with this, showing an example of usage.
This makes it easier to consolidate and add new architectures that OVMF supports, e.g. RISC-V, Raspberry Pi, etc.
I tested systemd-boot.basic test with this, which relies on EFI, so it should have tested this part of the code.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 22.11 Release Notes (or backporting 22.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
  • (Release notes changes) Ran nixos/doc/manual/md-to-db.sh to update generated release notes
• Fits CONTRIBUTING.md.

[danielfullmer]

LGTM, Thanks!

[roberth]

Could you add some tests to passthru.tests in the edk2 and ovmf packages?

I assume we already have tests for this, but I don't know.

[RaitoBezarius]

Could you add some tests to passthru.tests in the edk2 and ovmf packages?

I assume we already have tests for this, but I don't know.

We do not have direct tests for this, except that using EFI in NixOS tests are using ovmf (and then edk2) indirectly, would you like me to add the indirect tests?

[roberth]

OfBorg doesn't seem to pick up on the lowercase commit message prefix.

@ofborg build OVMF OVMF.passthru.tests

[RaitoBezarius]

@roberth unclear if https://logs.nix.ci/?key=nixos/nixpkgs.187887&attempt_id=a3efc083-4804-4b47-b326-aef7d9d3c51b is a failure or not to me.

[roberth]

@roberth unclear if https://logs.nix.ci/?key=nixos/nixpkgs.187887&attempt_id=a3efc083-4804-4b47-b326-aef7d9d3c51b is a failure or not to me.

It's a clean refactor producing the exact same derivation, so the problem isn't caused by this PR.