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

nixos/modules/virtualisation/qemu-vm.nix

@@ -98,12 +98,6 @@ let
   addDeviceNames =
     imap1 (idx: drive: drive // { device = driveDeviceName idx; });
 
-  efiPrefix =
-    if pkgs.stdenv.hostPlatform.isx86 then "${pkgs.OVMF.fd}/FV/OVMF"
-    else if pkgs.stdenv.isAarch64 then "${pkgs.OVMF.fd}/FV/AAVMF"
-    else throw "No EFI firmware available for platform";
-  efiFirmware = "${efiPrefix}_CODE.fd";
-  efiVarsDefault = "${efiPrefix}_VARS.fd";
 
   # Shell script to start the VM.
   startVM =
@@ -218,14 +212,14 @@ let
               ${qemu}/bin/qemu-img create -f qcow2 $diskImage "60M"
               ${if cfg.useEFIBoot then ''
                 efiVars=$out/efi-vars.fd
-                cp ${efiVarsDefault} $efiVars
+                cp ${cfg.efi.variables} $efiVars
                 chmod 0644 $efiVars
               '' else ""}
             '';
           buildInputs = [ pkgs.util-linux ];
           QEMU_OPTS = "-nographic -serial stdio -monitor none"
                       + lib.optionalString cfg.useEFIBoot (
-                        " -drive if=pflash,format=raw,unit=0,readonly=on,file=${efiFirmware}"
+                        " -drive if=pflash,format=raw,unit=0,readonly=on,file=${cfg.efi.firmware}"
                       + " -drive if=pflash,format=raw,unit=1,file=$efiVars");
         }
         ''
@@ -705,8 +699,31 @@ in
             manager.
             useEFIBoot is ignored if useBootLoader == false.
           '';
+        };
+
+    virtualisation.efi = {
+      firmware = mkOption {
+        type = types.path;
+        default = pkgs.OVMF.firmware;
+        defaultText = "pkgs.OVMF.firmware";
+        description =
+          lib.mdDoc ''
+            Firmware binary for EFI implementation, defaults to OVMF.
+          '';
       };
 
+      variables = mkOption {
+        type = types.path;
+        default = pkgs.OVMF.variables;
+        defaultText = "pkgs.OVMF.variables";
+        description =
+          lib.mdDoc ''
+            Platform-specific flash binary for EFI variables, implementation-dependent to the EFI firmware.
+            Defaults to OVMF.
+          '';
+      };
+    };
+
     virtualisation.useDefaultFilesystems =
       mkOption {
         type = types.bool;
@@ -928,7 +945,7 @@ in
         ''-append "$(cat ${config.system.build.toplevel}/kernel-params) init=${config.system.build.toplevel}/init regInfo=${regInfo}/registration ${consoles} $QEMU_KERNEL_PARAMS"''
       ])
       (mkIf cfg.useEFIBoot [
-        "-drive if=pflash,format=raw,unit=0,readonly=on,file=${efiFirmware}"
+        "-drive if=pflash,format=raw,unit=0,readonly=on,file=${cfg.efi.firmware}"
         "-drive if=pflash,format=raw,unit=1,file=$NIX_EFI_VARS"
       ])
       (mkIf (cfg.bios != null) [

pkgs/applications/virtualization/OVMF/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, lib, edk2, util-linux, nasm, acpica-tools
+{ stdenv, nixosTests, lib, edk2, util-linux, nasm, acpica-tools
 , csmSupport ? false, seabios ? null
 , secureBoot ? false
 , httpSupport ? false
@@ -19,9 +19,15 @@ let
     throw "Unsupported architecture";
 
   version = lib.getVersion edk2;
+
+  suffixes = {
+    x86_64 = "FV/OVMF";
+    aarch64 = "FV/AAVMF";
+  };
+
 in
 
-edk2.mkDerivation projectDscPath {
+edk2.mkDerivation projectDscPath (finalAttrs: {
   pname = "OVMF";
   inherit version;
 
@@ -62,10 +68,23 @@ edk2.mkDerivation projectDscPath {
 
   dontPatchELF = true;
 
+  passthru =
+  let
+    cpuName = stdenv.hostPlatform.parsed.cpu.name;
+    suffix = suffixes."${cpuName}" or (throw "Host cpu name `${cpuName}` is not supported in this OVMF derivation!");
+    prefix = "${finalAttrs.finalPackage.fd}/${suffix}";
+  in {
+    firmware  = "${prefix}_CODE.fd";
+    variables = "${prefix}_VARS.fd";
+    # This will test the EFI firmware for the host platform as part of the NixOS Tests setup.
+    tests.basic-systemd-boot = nixosTests.systemd-boot.basic;
+  };
+
   meta = {
     description = "Sample UEFI firmware for QEMU and KVM";
     homepage = "https://github.com/tianocore/tianocore.github.io/wiki/OVMF";
     license = lib.licenses.bsd2;
     platforms = ["x86_64-linux" "i686-linux" "aarch64-linux" "x86_64-darwin"];
+    maintainers = [ lib.maintainers.raitobezarius ];
   };
-}
+})

pkgs/development/compilers/edk2/default.nix

@@ -89,7 +89,7 @@ edk2 = buildStdenv.mkDerivation {
   passthru = {
     mkDerivation = projectDscPath: attrsOrFun: buildStdenv.mkDerivation (finalAttrs:
     let
-      attrs = if lib.isFunction attrsOrFun then (attrsOrFun finalAttrs) else attrsOrFun;
+      attrs = lib.toFunction attrsOrFun finalAttrs;
     in
     {
       inherit (edk2) src;