Merge pull request #197 from rn/ucode

Add support for Intel ucode

docs/yaml.md

@@ -47,6 +47,10 @@ contain a kernel modules directory. `cmdline` specifies the kernel command line
 To override the names, you can specify the kernel image name with `binary: bzImage` and the tar image
 with `tar: kernel.tar` or the empty string or `none` if you do not want to use a tarball at all.
 
+Kernel packages may also contain a cpio archive containing CPU microcode which needs prepending to
+the initrd. To select this option, recommended when booting on bare metal, add `ucode: intel-ucode.cpio`
+to the kernel section.
+
 ## `init`
 
 The `init` section is a list of images that are used for the `init` system and are unpacked directly

src/initrd/initrd.go

@@ -110,13 +110,13 @@ func CopyTar(w *Writer, r *tar.Reader) (written int64, err error) {
 	}
 }
 
-// CopySplitTar copies a tar stream into an initrd, but splits out kernel and cmdline
+// CopySplitTar copies a tar stream into an initrd, but splits out kernel, cmdline, and ucode
-func CopySplitTar(w *Writer, r *tar.Reader) (kernel []byte, cmdline string, err error) {
+func CopySplitTar(w *Writer, r *tar.Reader) (kernel []byte, cmdline string, ucode []byte, err error) {
 	for {
 		var thdr *tar.Header
 		thdr, err = r.Next()
 		if err == io.EOF {
-			return kernel, cmdline, nil
+			return kernel, cmdline, ucode, nil
 		}
 		if err != nil {
 			return
@@ -134,6 +134,11 @@ func CopySplitTar(w *Writer, r *tar.Reader) (kernel []byte, cmdline string, err
 				return
 			}
 			cmdline = string(buf)
+		case "boot/ucode.cpio":
+			ucode, err = ioutil.ReadAll(r)
+			if err != nil {
+				return
+			}
 		case "boot":
 			// skip this entry
 		default:

src/moby/build.go

@@ -176,9 +176,9 @@ func Build(m Moby, w io.Writer, pull bool, tp string) error {
 	dupMap := map[string]string{}
 
 	if m.Kernel.ref != nil {
-		// get kernel and initrd tarball from container
+		// get kernel and initrd tarball and ucode cpio archive from container
 		log.Infof("Extract kernel image: %s", m.Kernel.ref)
-		kf := newKernelFilter(iw, m.Kernel.Cmdline, m.Kernel.Binary, m.Kernel.Tar)
+		kf := newKernelFilter(iw, m.Kernel.Cmdline, m.Kernel.Binary, m.Kernel.Tar, m.Kernel.UCode)
 		err := ImageTar(m.Kernel.ref, "", kf, enforceContentTrust(m.Kernel.ref.String(), &m.Trust), pull, "")
 		if err != nil {
 			return fmt.Errorf("Failed to extract kernel image and tarball: %v", err)
@@ -259,13 +259,15 @@ type kernelFilter struct {
 	cmdline     string
 	kernel      string
 	tar         string
+	ucode       string
 	discard     bool
 	foundKernel bool
 	foundKTar   bool
+	foundUCode  bool
 }
 
-func newKernelFilter(tw *tar.Writer, cmdline string, kernel string, tar *string) *kernelFilter {
+func newKernelFilter(tw *tar.Writer, cmdline string, kernel string, tar, ucode *string) *kernelFilter {
-	tarName, kernelName := "kernel.tar", "kernel"
+	tarName, kernelName, ucodeName := "kernel.tar", "kernel", ""
 	if tar != nil {
 		tarName = *tar
 		if tarName == "none" {
@@ -275,7 +277,10 @@ func newKernelFilter(tw *tar.Writer, cmdline string, kernel string, tar *string)
 	if kernel != "" {
 		kernelName = kernel
 	}
-	return &kernelFilter{tw: tw, cmdline: cmdline, kernel: kernelName, tar: tarName}
+	if ucode != nil {
+		ucodeName = *ucode
+	}
+	return &kernelFilter{tw: tw, cmdline: cmdline, kernel: kernelName, tar: tarName, ucode: ucodeName}
 }
 
 func (k *kernelFilter) finishTar() error {
@@ -329,6 +334,8 @@ func (k *kernelFilter) WriteHeader(hdr *tar.Header) error {
 		}
 		k.foundKernel = true
 		k.discard = false
+		// If we handled the ucode, /boot already exist.
+		if !k.foundUCode {
 			whdr := &tar.Header{
 				Name:     "boot",
 				Mode:     0755,
@@ -337,8 +344,9 @@ func (k *kernelFilter) WriteHeader(hdr *tar.Header) error {
 			if err := tw.WriteHeader(whdr); err != nil {
 				return err
 			}
+		}
 		// add the cmdline in /boot/cmdline
-		whdr = &tar.Header{
+		whdr := &tar.Header{
 			Name: "boot/cmdline",
 			Mode: 0644,
 			Size: int64(len(k.cmdline)),
@@ -363,6 +371,28 @@ func (k *kernelFilter) WriteHeader(hdr *tar.Header) error {
 		k.foundKTar = true
 		k.discard = false
 		k.buffer = new(bytes.Buffer)
+	case k.ucode:
+		k.foundUCode = true
+		k.discard = false
+		// If we handled the kernel, /boot already exist.
+		if !k.foundKernel {
+			whdr := &tar.Header{
+				Name:     "boot",
+				Mode:     0755,
+				Typeflag: tar.TypeDir,
+			}
+			if err := tw.WriteHeader(whdr); err != nil {
+				return err
+			}
+		}
+		whdr := &tar.Header{
+			Name: "boot/ucode.cpio",
+			Mode: hdr.Mode,
+			Size: hdr.Size,
+		}
+		if err := tw.WriteHeader(whdr); err != nil {
+			return err
+		}
 	default:
 		k.discard = true
 	}

src/moby/config.go

@@ -36,6 +36,7 @@ type KernelConfig struct {
 	Cmdline string  `yaml:"cmdline,omitempty" json:"cmdline,omitempty"`
 	Binary  string  `yaml:"binary,omitempty" json:"binary,omitempty"`
 	Tar     *string `yaml:"tar,omitempty" json:"tar,omitempty"`
+	UCode   *string `yaml:"ucode,omitempty" json:"ucode,omitempty"`
 
 	ref *reference.Spec
 }
@@ -289,6 +290,9 @@ func AppendConfig(m0, m1 Moby) (Moby, error) {
 	if m1.Kernel.Tar != nil {
 		moby.Kernel.Tar = m1.Kernel.Tar
 	}
+	if m1.Kernel.UCode != nil {
+		moby.Kernel.UCode = m1.Kernel.UCode
+	}
 	if m1.Kernel.ref != nil {
 		moby.Kernel.ref = m1.Kernel.ref
 	}

src/moby/linuxkit.go

@@ -72,7 +72,7 @@ func ensureLinuxkitImage(name string) error {
 		return err
 	}
 	defer image.Close()
-	kernel, initrd, cmdline, err := tarToInitrd(image)
+	kernel, initrd, cmdline, _, err := tarToInitrd(image)
 	if err != nil {
 		return fmt.Errorf("Error converting to initrd: %v", err)
 	}

src/moby/output.go

@@ -27,22 +27,22 @@ const (
 
 var outFuns = map[string]func(string, io.Reader, int) error{
 	"kernel+initrd": func(base string, image io.Reader, size int) error {
-		kernel, initrd, cmdline, err := tarToInitrd(image)
+		kernel, initrd, cmdline, ucode, err := tarToInitrd(image)
 		if err != nil {
 			return fmt.Errorf("Error converting to initrd: %v", err)
 		}
-		err = outputKernelInitrd(base, kernel, initrd, cmdline)
+		err = outputKernelInitrd(base, kernel, initrd, cmdline, ucode)
 		if err != nil {
 			return fmt.Errorf("Error writing kernel+initrd output: %v", err)
 		}
 		return nil
 	},
 	"tar-kernel-initrd": func(base string, image io.Reader, size int) error {
-		kernel, initrd, cmdline, err := tarToInitrd(image)
+		kernel, initrd, cmdline, ucode, err := tarToInitrd(image)
 		if err != nil {
 			return fmt.Errorf("Error converting to initrd: %v", err)
 		}
-		if err := outputKernelInitrdTarball(base, kernel, initrd, cmdline); err != nil {
+		if err := outputKernelInitrdTarball(base, kernel, initrd, cmdline, ucode); err != nil {
 			return fmt.Errorf("Error writing kernel+initrd tarball output: %v", err)
 		}
 		return nil
@@ -62,10 +62,11 @@ var outFuns = map[string]func(string, io.Reader, int) error{
 		return nil
 	},
 	"raw-bios": func(base string, image io.Reader, size int) error {
-		kernel, initrd, cmdline, err := tarToInitrd(image)
+		kernel, initrd, cmdline, _, err := tarToInitrd(image)
 		if err != nil {
 			return fmt.Errorf("Error converting to initrd: %v", err)
 		}
+		// TODO: Handle ucode
 		err = outputImg(rawBios, base+"-bios.img", kernel, initrd, cmdline)
 		if err != nil {
 			return fmt.Errorf("Error writing raw-bios output: %v", err)
@@ -73,7 +74,7 @@ var outFuns = map[string]func(string, io.Reader, int) error{
 		return nil
 	},
 	"raw-efi": func(base string, image io.Reader, size int) error {
-		kernel, initrd, cmdline, err := tarToInitrd(image)
+		kernel, initrd, cmdline, _, err := tarToInitrd(image)
 		if err != nil {
 			return fmt.Errorf("Error converting to initrd: %v", err)
 		}
@@ -86,7 +87,7 @@ var outFuns = map[string]func(string, io.Reader, int) error{
 	"aws": func(base string, image io.Reader, size int) error {
 		filename := base + ".raw"
 		log.Infof("  %s", filename)
-		kernel, initrd, cmdline, err := tarToInitrd(image)
+		kernel, initrd, cmdline, _, err := tarToInitrd(image)
 		if err != nil {
 			return fmt.Errorf("Error converting to initrd: %v", err)
 		}
@@ -97,7 +98,7 @@ var outFuns = map[string]func(string, io.Reader, int) error{
 		return nil
 	},
 	"gcp": func(base string, image io.Reader, size int) error {
-		kernel, initrd, cmdline, err := tarToInitrd(image)
+		kernel, initrd, cmdline, _, err := tarToInitrd(image)
 		if err != nil {
 			return fmt.Errorf("Error converting to initrd: %v", err)
 		}
@@ -110,10 +111,11 @@ var outFuns = map[string]func(string, io.Reader, int) error{
 	"qcow2-bios": func(base string, image io.Reader, size int) error {
 		filename := base + ".qcow2"
 		log.Infof("  %s", filename)
-		kernel, initrd, cmdline, err := tarToInitrd(image)
+		kernel, initrd, cmdline, _, err := tarToInitrd(image)
 		if err != nil {
 			return fmt.Errorf("Error converting to initrd: %v", err)
 		}
+		// TODO: Handle ucode
 		err = outputLinuxKit("qcow2", filename, kernel, initrd, cmdline, size)
 		if err != nil {
 			return fmt.Errorf("Error writing qcow2 output: %v", err)
@@ -121,7 +123,7 @@ var outFuns = map[string]func(string, io.Reader, int) error{
 		return nil
 	},
 	"vhd": func(base string, image io.Reader, size int) error {
-		kernel, initrd, cmdline, err := tarToInitrd(image)
+		kernel, initrd, cmdline, _, err := tarToInitrd(image)
 		if err != nil {
 			return fmt.Errorf("Error converting to initrd: %v", err)
 		}
@@ -132,7 +134,7 @@ var outFuns = map[string]func(string, io.Reader, int) error{
 		return nil
 	},
 	"dynamic-vhd": func(base string, image io.Reader, size int) error {
-		kernel, initrd, cmdline, err := tarToInitrd(image)
+		kernel, initrd, cmdline, _, err := tarToInitrd(image)
 		if err != nil {
 			return fmt.Errorf("Error converting to initrd: %v", err)
 		}
@@ -143,7 +145,7 @@ var outFuns = map[string]func(string, io.Reader, int) error{
 		return nil
 	},
 	"vmdk": func(base string, image io.Reader, size int) error {
-		kernel, initrd, cmdline, err := tarToInitrd(image)
+		kernel, initrd, cmdline, _, err := tarToInitrd(image)
 		if err != nil {
 			return fmt.Errorf("Error converting to initrd: %v", err)
 		}
@@ -220,16 +222,16 @@ func Formats(base string, image string, formats []string, size int) error {
 	return nil
 }
 
-func tarToInitrd(r io.Reader) ([]byte, []byte, string, error) {
+func tarToInitrd(r io.Reader) ([]byte, []byte, string, []byte, error) {
 	w := new(bytes.Buffer)
 	iw := initrd.NewWriter(w)
 	tr := tar.NewReader(r)
-	kernel, cmdline, err := initrd.CopySplitTar(iw, tr)
+	kernel, cmdline, ucode, err := initrd.CopySplitTar(iw, tr)
 	if err != nil {
-		return []byte{}, []byte{}, "", err
+		return []byte{}, []byte{}, "", []byte{}, err
 	}
 	iw.Close()
-	return kernel, w.Bytes(), cmdline, nil
+	return kernel, w.Bytes(), cmdline, ucode, nil
 }
 
 func tarInitrdKernel(kernel, initrd []byte, cmdline string) (*bytes.Buffer, error) {
@@ -314,21 +316,35 @@ func outputRPi3(image, filename string, filesystem io.Reader) error {
 	return dockerRun(filesystem, output, true, image)
 }
 
-func outputKernelInitrd(base string, kernel []byte, initrd []byte, cmdline string) error {
+func outputKernelInitrd(base string, kernel []byte, initrd []byte, cmdline string, ucode []byte) error {
 	log.Debugf("output kernel/initrd: %s %s", base, cmdline)
-	log.Infof("  %s %s %s", base+"-kernel", base+"-initrd.img", base+"-cmdline")
+
-	err := ioutil.WriteFile(base+"-initrd.img", initrd, os.FileMode(0644))
+	if len(ucode) != 0 {
+		log.Infof("  %s ucode+%s %s", base+"-kernel", base+"-initrd.img", base+"-cmdline")
+		if err := ioutil.WriteFile(base+"-initrd.img", ucode, os.FileMode(0644)); err != nil {
+			return err
+		}
+		f, err := os.OpenFile(base+"-initrd.img", os.O_APPEND|os.O_WRONLY, 0644)
 		if err != nil {
 			return err
 		}
-	err = ioutil.WriteFile(base+"-kernel", kernel, os.FileMode(0644))
+		defer f.Close()
-	if err != nil {
+		if _, err = f.Write(initrd); err != nil {
+			return err
+		}
+	} else {
+		log.Infof("  %s %s %s", base+"-kernel", base+"-initrd.img", base+"-cmdline")
+		if err := ioutil.WriteFile(base+"-initrd.img", initrd, os.FileMode(0644)); err != nil {
+			return err
+		}
+	}
+	if err := ioutil.WriteFile(base+"-kernel", kernel, os.FileMode(0644)); err != nil {
 		return err
 	}
 	return ioutil.WriteFile(base+"-cmdline", []byte(cmdline), os.FileMode(0644))
 }
 
-func outputKernelInitrdTarball(base string, kernel []byte, initrd []byte, cmdline string) error {
+func outputKernelInitrdTarball(base string, kernel []byte, initrd []byte, cmdline string, ucode []byte) error {
 	log.Debugf("output kernel/initrd tarball: %s %s", base, cmdline)
 	log.Infof("  %s", base+"-initrd.tar")
 	f, err := os.Create(base + "-initrd.tar")
@@ -370,5 +386,18 @@ func outputKernelInitrdTarball(base string, kernel []byte, initrd []byte, cmdlin
 	if _, err := tw.Write([]byte(cmdline)); err != nil {
 		return err
 	}
+	if len(ucode) != 0 {
+		hdr := &tar.Header{
+			Name: "ucode.cpio",
+			Mode: 0644,
+			Size: int64(len(ucode)),
+		}
+		if err := tw.WriteHeader(hdr); err != nil {
+			return err
+		}
+		if _, err := tw.Write(ucode); err != nil {
+			return err
+		}
+	}
 	return tw.Close()
 }

src/moby/schema.go

@@ -13,7 +13,8 @@ var schema = string(`
         "image": {"type": "string"},
         "cmdline": {"type": "string"},
         "binary": {"type": "string"},
-        "tar": {"type": "string"}
+        "tar": {"type": "string"},
+        "ucode": {"type": "string"}
       }
     },
     "file": {