nixos: fixup build of aarch64 minimal ISO (fixes #109252)

Perhaps it's not pretty nor precise; feel free to improve.

nixos/modules/installer/cd-dvd/iso-image.nix

@@ -397,6 +397,8 @@ let
   # Syslinux (and isolinux) only supports x86-based architectures.
   canx86BiosBoot = pkgs.stdenv.isi686 || pkgs.stdenv.isx86_64;
 
+  # Some modules apparently aren't present on our aarch64 (and maybe elsewhere).
+  maybeInitrdModules = lib.optionals (!pkgs.stdenv.hostPlatform.isAarch64);
 in
 
 {
@@ -615,9 +617,11 @@ in
         ];
       };
 
-    boot.initrd.availableKernelModules = [ "squashfs" "iso9660" "uas" "overlay" ];
+    boot.initrd.availableKernelModules = [ "iso9660" "uas" "overlay" ]
+      ++ maybeInitrdModules [ "squashfs" ];
 
-    boot.initrd.kernelModules = [ "loop" "overlay" ];
+    boot.initrd.kernelModules = [ "overlay" ]
+      ++ maybeInitrdModules [ "loop" ];
 
     # Closures to be copied to the Nix store on the CD, namely the init
     # script and the top-level system configuration directory.
@@ -716,7 +720,7 @@ in
 
     # Add vfat support to the initrd to enable people to copy the
     # contents of the CD to a bootable USB stick.
-    boot.initrd.supportedFilesystems = [ "vfat" ];
+    boot.initrd.supportedFilesystems = maybeInitrdModules [ "vfat" ];
 
   };
 

nixos/modules/profiles/all-hardware.nix

@@ -3,20 +3,24 @@
 # enabled in the initrd.  Its primary use is in the NixOS installation
 # CDs.
 
-{ ... }:
+{ pkgs, lib,... }:
-
+let
+  platform = pkgs.stdenv.hostPlatform;
+in
 {
 
   # The initrd has to contain any module that might be necessary for
   # supporting the most important parts of HW like drives.
   boot.initrd.availableKernelModules =
-    [ # SATA/PATA support.
+      # SATA/PATA support.
+    lib.optionals (!platform.isAarch64) [ # not sure where else they're missing
       "ahci"
-
+      "sata_sil24"
+    ] ++ [
       "ata_piix"
 
       "sata_inic162x" "sata_nv" "sata_promise" "sata_qstor"
-      "sata_sil" "sata_sil24" "sata_sis" "sata_svw" "sata_sx4"
+      "sata_sil" "sata_sis" "sata_svw" "sata_sx4"
       "sata_uli" "sata_via" "sata_vsc"
 
       "pata_ali" "pata_amd" "pata_artop" "pata_atiixp" "pata_efar"
@@ -38,13 +42,19 @@
       # Firewire support.  Not tested.
       "ohci1394" "sbp2"
 
+    ] ++ lib.optionals (!platform.isAarch64) [ # not sure where else they're missing
       # Virtio (QEMU, KVM etc.) support.
       "virtio_net" "virtio_pci" "virtio_blk" "virtio_scsi" "virtio_balloon" "virtio_console"
+    ] ++ [
 
       # VMware support.
-      "mptspi" "vmw_balloon" "vmwgfx" "vmw_vmci" "vmw_vsock_vmci_transport" "vmxnet3" "vsock"
+      "mptspi" "vmxnet3" "vsock"
+    ] ++ lib.optionals (!platform.isAarch64) [ # not sure where else they're missing
+      "vmw_vmci" "vmwgfx" "vmw_vsock_vmci_transport"
+    ] ++ lib.optional platform.isx86 "vmw_balloon"
 
       # Hyper-V support.
+    ++ lib.optionals (!platform.isAarch64) [ # not sure where else they're missing
       "hv_storvsc"
     ];
 

nixos/modules/system/boot/kernel.nix

@@ -194,31 +194,37 @@ in
 
   config = mkMerge
     [ (mkIf config.boot.initrd.enable {
-        boot.initrd.availableKernelModules =
+        boot.initrd.availableKernelModules = let
-          [ # Note: most of these (especially the SATA/PATA modules)
+          # Some modules apparently aren't present on our aarch64 (and maybe elsewhere).
+          maybeInitrdModules = lib.optionals (!pkgs.stdenv.hostPlatform.isAarch64);
+        in
+            # Note: most of these (especially the SATA/PATA modules)
             # shouldn't be included by default since nixos-generate-config
             # detects them, but I'm keeping them for now for backwards
             # compatibility.
 
             # Some SATA/PATA stuff.
-            "ahci"
+          maybeInitrdModules [ "ahci" ]
+          ++ [
             "sata_nv"
             "sata_via"
             "sata_sis"
             "sata_uli"
             "ata_piix"
             "pata_marvell"
+          ]
 
             # Standard SCSI stuff.
-            "sd_mod"
+          ++ maybeInitrdModules [ "sd_mod" ]
-            "sr_mod"
+          ++ [ "sr_mod" ]
 
             # SD cards and internal eMMC drives.
-            "mmc_block"
+          ++ maybeInitrdModules [ "mmc_block" ]
 
             # Support USB keyboards, in case the boot fails and we only have
             # a USB keyboard, or for LUKS passphrase prompt.
-            "uhci_hcd"
+          ++ [ "uhci_hcd" ]
+          ++ maybeInitrdModules [
             "ehci_hcd"
             "ehci_pci"
             "ohci_hcd"

nixos/modules/tasks/filesystems/ext.nix

@@ -1,4 +1,4 @@
-{ pkgs, ... }:
+{ pkgs, lib, ... }:
 
 {
   config = {
@@ -6,7 +6,10 @@
     system.fsPackages = [ pkgs.e2fsprogs ];
 
     # As of kernel 4.3, there is no separate ext3 driver (they're also handled by ext4.ko)
-    boot.initrd.availableKernelModules = [ "ext2" "ext4" ];
+    # No ext* modules are present on our aarch64, apparently (and maybe elsewhere).
+    boot.initrd.availableKernelModules =
+      lib.optionals (!pkgs.stdenv.hostPlatform.isAarch64)
+        [ "ext2" "ext4" ];
 
     boot.initrd.extraUtilsCommands =
       ''