Split kernel configuration in files

configuration.nix

@@ -18,11 +18,19 @@
 
   system.stateVersion = "24.05";
 
-  boot.kernelPackages = lib.mkForce pkgs.linuxPackagesCustom;
+  #boot.kernelPackages = lib.mkForce pkgs.linuxPackagesCustom;
+
+  boot.kernelPatches = [ {
+    name = "riscv-common";
+    patch = null;
+    extraConfig = ''
+      KEXEC y
+    '';
+  } ];
 
   boot.kernelParams = [
-    "console=ttyS0,115200"
     "console=tty1"
+    "console=ttyS0,115200"
   ];
 
   services.getty.autologinUser = "test";

flake.nix

@@ -35,6 +35,7 @@
         modules = [
           ./configuration.nix
           ./lagarto-hun.nix
+          ./no-compressed.nix
         ];
       };
     };

lagarto-hun.nix

@@ -1,7 +1,7 @@
 { config, lib, pkgs, modulesPath, ... }:
 
 let
-  overlay = prev: final: {
+  overlay = final: prev: {
     uboot = prev.ubootQemuRiscv64Smode.override {
       filesToInstall = [ "u-boot.bin" "u-boot-nodtb.bin" ];
       extraConfig = ''
@@ -60,4 +60,21 @@ let
   };
 in {
   nixpkgs.overlays = [ overlay ];
+
+  #boot.kernelPackages = pkgs.linuxPackages_latest;
+  boot.kernelPatches = [
+    {
+      name = assert false; "sbi-early-console";
+      patch = null;
+      extraConfig = ''
+        # Early console via SBI
+        RISCV_SBI y
+        RISCV_SBI_V01 y
+        SERIAL_EARLYCON y
+        SERIAL_EARLYCON_RISCV_SBI y
+        HVC_DRIVER y
+        HVC_RISCV_SBI y
+      '';
+    }
+  ];
 }

no-compressed.nix

@@ -10,4 +10,14 @@
   # FIXME: Broken as rustc injects compressed instructions.
   # For now we disable it.
   services.nscd.enableNsncd = false;
+
+  boot.kernelPatches = [ {
+    name = "disable-compressed";
+    patch = null;
+    extraConfig = ''
+      RISCV_ISA_C n
+      NONPORTABLE y
+      EFI n
+    '';
+  } ];
 }

vm.nix

@@ -9,6 +9,7 @@
 
   boot = {
     kernelParams = [ "boot.shell_on_fail" ];
+    #kernelPackages = lib.mkForce pkgs.linuxPackagesCustom;
     consoleLogLevel = lib.mkDefault 7;
     initrd.kernelModules = [
       "virtio_pci"
@@ -18,6 +19,36 @@
       "9pnet_virtio"
     ];
 
+    kernelPatches = [ {
+      name = "qemu";
+      patch = null;
+      extraConfig = ''
+        # For qemu
+        BLOCK y
+        BLK_DEV y
+        DEVTMPFS y
+        VIRTIO_MENU y
+        VIRTIO_BLK y
+        VIRTIO_NET y
+        EXT4_FS y
+
+        # For 9P: https://wiki.qemu.org/Documentation/9psetup
+        NET_9P y
+        NET_9P_VIRTIO y
+        NET_9P_DEBUG y
+        NET_DEVICES y
+        NET_CORE y
+        INET y
+        NETWORK_FILESYSTEMS y
+        OVERLAY_FS y
+        "9P_FS" y
+        "9P_FS_POSIX_ACL" y
+        PCI y
+        VIRTIO_PCI y
+        PCI_HOST_GENERIC y
+      '';
+    } ];
+
     loader = {
       grub.enable = false;
       generic-extlinux-compatible.enable = true;