Add a way to load CPU microcode into booster image

As a stopgap solution for platforms that do not provide the microcode as
a separate image.

Discussion #159

docs/manpage.md

@@ -71,6 +71,8 @@ Booster advantages:
 
  * `enable_zfs` is a flag that enables ZFS filesystem as root filesystem. This flag also makes sure all the required modules/binaries are added to the image. Note that if ZFS is enabled then `zfs=` boot option must be used instead of `root=` boot option.
 
+ * `enable_microcode` is a flag makes booster generator detect microcode file for the current CPU, add it to image and later load it the early boot stages.
+
 Once you are done modifying your config file and want to regenerate booster images under `/boot` please use `/usr/lib/booster/regenerate_images`.
 It is a convenience script that performs the same type of image regeneration as if you installed `booster` with your package manager.
 

generator/config.go

@@ -38,6 +38,7 @@ type UserConfig struct {
 	EnableZfs            bool   `yaml:"enable_zfs"`
 	ZfsImportParams      string `yaml:"zfs_import_params"`
 	ZfsCachePath         string `yaml:"zfs_cache_path"`
+	EnableMicrocode      bool   `yaml:"enable_zfs"`
 }
 
 // read user config from the specified file. If file parameter is empty string then "empty" configuration is considered
@@ -149,6 +150,7 @@ func readGeneratorConfig(file string) (*generatorConfig, error) {
 	conf.enableZfs = u.EnableZfs
 	conf.zfsImportParams = u.ZfsImportParams
 	conf.zfsCachePath = u.ZfsCachePath
+	conf.enableMicrocode = u.EnableMicrocode
 	conf.enableVirtualConsole = u.EnableVirtualConsole
 	if conf.enableVirtualConsole {
 		conf.vconsolePath = "/etc/vconsole.conf"

generator/generator.go

@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/cavaliergopher/cpio"
+	"github.com/klauspost/cpuid/v2"
 	"gopkg.in/yaml.v3"
 )
 
@@ -45,6 +46,7 @@ type generatorConfig struct {
 	// virtual console configs
 	enableVirtualConsole     bool
 	vconsolePath, localePath string
+	enableMicrocode          bool
 }
 
 type networkStaticConfig struct {
@@ -64,6 +66,9 @@ const (
 var (
 	imageModulesDir = "/usr/lib/modules/"
 	firmwareDir     = "/usr/lib/firmware/"
+
+	intelUcodeDir = "/lib/firmware/intel-ucode"
+	amdUcodeDir   = "/usr/lib/firmware/amd-ucode"
 )
 
 // This is default modules list checked by booster. It either specifies a name of the module
@@ -228,6 +233,43 @@ func generateInitRamfs(conf *generatorConfig) error {
 		}
 	}
 
+	if conf.enableMicrocode {
+		if conf.universal {
+			// we detect microcode file for specific host/platform. This logic does not work with universal images currently.
+			return fmt.Errorf("microcode detection does not work with universal images")
+		}
+
+		infile := ""
+		outfile := ""
+		vendor := cpuid.CPU.VendorID
+		switch vendor {
+		case cpuid.Intel:
+			family := cpuid.CPU.Family
+			model := cpuid.CPU.Model
+			stepping := 10 // cpuid.CPU.Stepping
+			infile = fmt.Sprintf("%s/%02x-%02x-%02x", intelUcodeDir, family, model, stepping)
+			outfile = "GenuineIntel.bin"
+		case cpuid.AMD:
+			family := cpuid.CPU.Family
+			if family >= 21 {
+				infile = fmt.Sprintf("%s/microcode_amd_fam%xh.bin", amdUcodeDir, family)
+			} else {
+				infile = fmt.Sprintf("%s/microcode_amd.bin", amdUcodeDir)
+			}
+			outfile = "AuthenticAMD.bin"
+		default:
+			return fmt.Errorf("unable to find microcode for processor vendor %s", vendor.String())
+		}
+
+		content, err := os.ReadFile(infile)
+		if err != nil {
+			return err
+		}
+		if err := img.AppendContent("/kernel/x86/microcode/"+outfile, 0644, content); err != nil {
+			return err
+		}
+	}
+
 	if err := img.appendInitConfig(conf, kmod, vconsole); err != nil {
 		return err
 	}

generator/generator_test.go

@@ -65,6 +65,7 @@ type options struct {
 	vConsoleConfig, localeConfig string
 	enableMdraid                 bool
 	mdraidConfigPath             string
+	microcode                    bool
 }
 
 func generateAliasesFile(aliases []alias) []byte {
@@ -179,6 +180,7 @@ func createTestInitRamfs(t *testing.T, o *options) {
 		enableLVM:           o.enableLVM,
 		enableMdraid:        o.enableMdraid,
 		mdraidConfigPath:    o.mdraidConfigPath,
+		enableMicrocode:     o.microcode,
 	}
 	if o.vConsoleConfig != "" {
 		conf.enableVirtualConsole = true
@@ -554,3 +556,28 @@ func TestModprobeOptions(t *testing.T) {
 	}
 	require.Equal(t, expect, cfg.ModprobeOptions)
 }
+
+func TestMicrocode(t *testing.T) {
+	// both Intel and AMD ucode dirs must exist to be able to run this test
+	if _, err := os.Stat("/lib/firmware/intel-ucode"); err != nil {
+		t.Skip(err)
+	}
+	if _, err := os.Stat("/lib/firmware/amd-ucode"); err != nil {
+		t.Skip(err)
+	}
+
+	opts := options{
+		microcode:   true,
+		unpackImage: true,
+	}
+	createTestInitRamfs(t, &opts)
+
+	dir := opts.workDir + "/image.unpacked/kernel/x86/microcode/"
+	checkFileExistence(t, dir)
+
+	entries, err := os.ReadDir(dir)
+	require.NoError(t, err)
+	require.Len(t, entries, 1)
+	name := entries[0].Name()
+	require.True(t, name == "GenuineIntel.bin" || name == "AuthenticAMD.bin")
+}

go.mod

@@ -16,6 +16,7 @@ require (
 	github.com/insomniacslk/dhcp v0.0.0-20220504074936-1ca156eafb9f
 	github.com/jessevdk/go-flags v1.5.0
 	github.com/klauspost/compress v1.15.8
+	github.com/klauspost/cpuid/v2 v2.1.0
 	github.com/stretchr/testify v1.8.0
 	github.com/ulikunitz/xz v0.5.10
 	github.com/vishvananda/netlink v1.1.0

go.sum

@@ -107,6 +107,8 @@ github.com/kisielk/errcheck v1.1.0/go.mod h1:EZBBE59ingxPouuu3KfxchcWSUPOHkagtvW
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
 github.com/klauspost/compress v1.15.8 h1:JahtItbkWjf2jzm/T+qgMxkP9EMHsqEUA6vCMGmXvhA=
 github.com/klauspost/compress v1.15.8/go.mod h1:PhcZ0MbTNciWF3rruxRgKxI5NkcHHrHUDtV4Yw2GlzU=
+github.com/klauspost/cpuid/v2 v2.1.0 h1:eyi1Ad2aNJMW95zcSbmGg7Cg6cq3ADwLpMAP96d8rF0=
+github.com/klauspost/cpuid/v2 v2.1.0/go.mod h1:RVVoqg1df56z8g3pUjL/3lE5UfnlrJX8tyFgg4nqhuY=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/kr/logfmt v0.0.0-20140226030751-b84e30acd515/go.mod h1:+0opPa2QZZtGFBFZlji/RkVcI2GknAs/DXo4wKdlNEc=
 github.com/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
@@ -267,6 +269,7 @@ golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20210525143221-35b2ab0089ea/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210629170331-7dc0b73dc9fb/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220704084225-05e143d24a9e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220712014510-0a85c31ab51e h1:NHvCuwuS43lGnYhten69ZWqi2QOj/CiDNcKbVqwVoew=
 golang.org/x/sys v0.0.0-20220712014510-0a85c31ab51e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=