nixos-generate-config: automatically enable microcode updates

nixos/modules/installer/tools/nixos-generate-config.pl

@@ -91,6 +91,11 @@ sub hasCPUFeature {
 }
 
 
+sub cpuManufacturer {
+    my $id = shift;
+    return $cpuinfo =~ /^vendor_id\s*:.* $id$/m;
+}
+
 
 # Determine CPU governor to use
 if (-e "/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors") {
@@ -111,6 +116,9 @@ if (-e "/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors") {
 push @kernelModules, "kvm-intel" if hasCPUFeature "vmx";
 push @kernelModules, "kvm-amd" if hasCPUFeature "svm";
 
+push @attrs, "hardware.cpu.amd.updateMicrocode = lib.mkDefault config.hardware.enableRedistributableFirmware;" if cpuManufacturer "AuthenticAMD";
+push @attrs, "hardware.cpu.intel.updateMicrocode = lib.mkDefault config.hardware.enableRedistributableFirmware;" if cpuManufacturer "GenuineIntel";
+
 
 # Look at the PCI devices and add necessary modules.  Note that most
 # modules are auto-detected so we don't need to list them here.