Add vmType.vz.diskImageFormat that accepts "raw" or "asif"

- Add `vmType.vz.diskImageFormat` that accepts "raw" or "asif"
```yaml
vmOpts:
  vz:
    diskImageFormat: null
    # Specify the disk image format: "raw" or "asif".
    # Currently only applies to the primary disk image.
    # "asif" requires macOS 26+, and does not support converting back to "raw".
    # 🟢 Builtin default: "raw"
```
- Dropped `LIMA_VZ_ASIF` environment variable

Signed-off-by: Norio Nomura <[email protected]>

Author: norio-nomura

pkg/driver/vz/disk.go

@@ -9,32 +9,30 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
-	"strconv"
 
-	"github.com/coreos/go-semver/semver"
 	"github.com/docker/go-units"
-	"github.com/sirupsen/logrus"
+	"github.com/lima-vm/go-qcow2reader/image"
+	"github.com/lima-vm/go-qcow2reader/image/asif"
 
 	"github.com/lima-vm/lima/v2/pkg/imgutil/proxyimgutil"
 	"github.com/lima-vm/lima/v2/pkg/iso9660util"
-	"github.com/lima-vm/lima/v2/pkg/limatype"
 	"github.com/lima-vm/lima/v2/pkg/limatype/filenames"
-	"github.com/lima-vm/lima/v2/pkg/osutil"
 )
 
-func EnsureDisk(ctx context.Context, inst *limatype.Instance) error {
-	diffDisk := filepath.Join(inst.Dir, filenames.DiffDisk)
+// EnsureDisk ensures that the diff disk exists with the specified size and format.
+func EnsureDisk(ctx context.Context, instDir, diskSize string, diskImageFormat image.Type) error {
+	diffDisk := filepath.Join(instDir, filenames.DiffDisk)
 	if _, err := os.Stat(diffDisk); err == nil || !errors.Is(err, os.ErrNotExist) {
 		// disk is already ensured
 		return err
 	}
 
 	diskUtil := proxyimgutil.NewDiskUtil(ctx)
 
-	baseDisk := filepath.Join(inst.Dir, filenames.BaseDisk)
+	baseDisk := filepath.Join(instDir, filenames.BaseDisk)
 
-	diskSize, _ := units.RAMInBytes(*inst.Config.Disk)
-	if diskSize == 0 {
+	diskSizeInBytes, _ := units.RAMInBytes(diskSize)
+	if diskSizeInBytes == 0 {
 		return nil
 	}
 	isBaseDiskISO, err := iso9660util.IsISO9660(baseDisk)
@@ -56,44 +54,13 @@ func EnsureDisk(ctx context.Context, inst *limatype.Instance) error {
 		return diffDiskF.Close()
 	}
 	// Check whether to use ASIF format
+
 	converter := diskUtil.ConvertToASIF
-	if !determineUseASIF() {
+	if diskImageFormat != asif.Type {
 		converter = diskUtil.ConvertToRaw
 	}
-	if err = converter(ctx, baseDisk, diffDisk, &diskSize, false); err != nil {
+	if err = converter(ctx, baseDisk, diffDisk, &diskSizeInBytes, false); err != nil {
 		return fmt.Errorf("failed to convert %q to a disk %q: %w", baseDisk, diffDisk, err)
 	}
 	return err
 }
-
-func determineUseASIF() bool {
-	var useASIF bool
-	if macOSProductVersion, err := osutil.ProductVersion(); err != nil {
-		logrus.WithError(err).Warn("Failed to get macOS product version; using raw format instead of ASIF")
-	} else if macOSProductVersion.LessThan(*semver.New("26.0.0")) {
-		logrus.Infof("macOS version %q does not support ASIF format; using raw format instead", macOSProductVersion)
-	} else {
-		// TODO: change default to true,
-		// if the conversion from ASIF to raw while preserving sparsity is implemented,
-		// or if enough testing is done to confirm that interoperability issues won't happen with ASIF.
-		useASIF = false
-		// allow overriding via LIMA_VZ_ASIF environment variable
-		if envVar := os.Getenv("LIMA_VZ_ASIF"); envVar != "" {
-			if b, err := strconv.ParseBool(envVar); err != nil {
-				logrus.WithError(err).Warnf("invalid LIMA_VZ_ASIF value %q", envVar)
-			} else {
-				useASIF = b
-				uses := "ASIF"
-				if !useASIF {
-					uses = "raw"
-				}
-				logrus.Infof("LIMA_VZ_ASIF=%s; using %s format to diff disk", envVar, uses)
-			}
-		} else if useASIF {
-			logrus.Info("using ASIF format for the disk image")
-		} else {
-			logrus.Info("using raw format for the disk image")
-		}
-	}
-	return useASIF
-}

pkg/driver/vz/vz_driver_darwin.go

@@ -17,6 +17,9 @@ import (
 
 	"github.com/Code-Hex/vz/v3"
 	"github.com/coreos/go-semver/semver"
+	"github.com/lima-vm/go-qcow2reader/image"
+	"github.com/lima-vm/go-qcow2reader/image/asif"
+	"github.com/lima-vm/go-qcow2reader/image/raw"
 	"github.com/sirupsen/logrus"
 
 	"github.com/lima-vm/lima/v2/pkg/driver"
@@ -74,11 +77,12 @@ const Enabled = true
 type LimaVzDriver struct {
 	Instance *limatype.Instance
 
-	SSHLocalPort   int
-	vSockPort      int
-	virtioPort     string
-	rosettaEnabled bool
-	rosettaBinFmt  bool
+	SSHLocalPort    int
+	vSockPort       int
+	virtioPort      string
+	rosettaEnabled  bool
+	rosettaBinFmt   bool
+	diskImageFormat image.Type
 
 	machine                    *virtualMachineWrapper
 	waitSSHLocalPortAccessible <-chan any
@@ -124,6 +128,11 @@ func (l *LimaVzDriver) Configure(inst *limatype.Instance) *driver.ConfiguredDriv
 	if vzOpts.Rosetta.BinFmt != nil {
 		l.rosettaBinFmt = *vzOpts.Rosetta.BinFmt
 	}
+	if vzOpts.DiskImageFormat != nil {
+		l.diskImageFormat = *vzOpts.DiskImageFormat
+	} else {
+		l.diskImageFormat = raw.Type
+	}
 
 	return &driver.ConfiguredDriver{
 		Driver: l,
@@ -160,6 +169,9 @@ func (l *LimaVzDriver) FillConfig(ctx context.Context, cfg *limatype.LimaYAML, _
 	if vzOpts.Rosetta.BinFmt == nil {
 		vzOpts.Rosetta.BinFmt = ptr.Of(false)
 	}
+	if vzOpts.DiskImageFormat == nil {
+		vzOpts.DiskImageFormat = ptr.Of(raw.Type)
+	}
 
 	var opts any
 	if err := limayaml.Convert(vzOpts, &opts, ""); err != nil {
@@ -285,6 +297,19 @@ func validateConfig(_ context.Context, cfg *limatype.LimaYAML) error {
 	default:
 		logrus.Warnf("field `video.display` must be \"vz\", \"default\", or \"none\" for VZ driver , got %q", videoDisplay)
 	}
+	var vzOpts limatype.VZOpts
+	if err := limayaml.Convert(cfg.VMOpts[limatype.VZ], &vzOpts, "vmOpts.vz"); err != nil {
+		logrus.WithError(err).Warnf("Couldn't convert %q", cfg.VMOpts[limatype.VZ])
+	}
+	switch *vzOpts.DiskImageFormat {
+	case raw.Type:
+	case asif.Type:
+		if macOSProductVersion.LessThan(*semver.New("26.0.0")) {
+			return fmt.Errorf("vmOpts.vz.diskImageFormat=%q requires macOS 26 or higher to run, got %q", asif.Type, macOSProductVersion)
+		}
+	default:
+		return fmt.Errorf("field `vmOpts.vz.diskImageFormat` must be %q or %q, got %q", raw.Type, asif.Type, *vzOpts.DiskImageFormat)
+	}
 	return nil
 }
 
@@ -294,7 +319,7 @@ func (l *LimaVzDriver) Create(_ context.Context) error {
 }
 
 func (l *LimaVzDriver) CreateDisk(ctx context.Context) error {
-	return EnsureDisk(ctx, l.Instance)
+	return EnsureDisk(ctx, l.Instance.Dir, *l.Instance.Config.Disk, l.diskImageFormat)
 }
 
 func (l *LimaVzDriver) Start(ctx context.Context) (chan error, error) {

pkg/imgutil/nativeimgutil/fuzz_test.go

@@ -8,6 +8,7 @@ import (
 	"path/filepath"
 	"testing"
 
+	"github.com/lima-vm/go-qcow2reader/image/raw"
 	"gotest.tools/v3/assert"
 )
 
@@ -17,6 +18,6 @@ func FuzzConvertToRaw(f *testing.F) {
 		destPath := filepath.Join(t.TempDir(), "dest.img")
 		err := os.WriteFile(srcPath, imgData, 0o600)
 		assert.NilError(t, err)
-		_ = convertTo(imageRaw, srcPath, destPath, &size, withBacking)
+		_ = convertTo(raw.Type, srcPath, destPath, &size, withBacking)
 	})
 }

pkg/imgutil/nativeimgutil/nativeimgutil.go

@@ -19,6 +19,7 @@ import (
 	"github.com/docker/go-units"
 	"github.com/lima-vm/go-qcow2reader"
 	"github.com/lima-vm/go-qcow2reader/convert"
+	"github.com/lima-vm/go-qcow2reader/image"
 	"github.com/lima-vm/go-qcow2reader/image/asif"
 	"github.com/lima-vm/go-qcow2reader/image/qcow2"
 	"github.com/lima-vm/go-qcow2reader/image/raw"
@@ -42,17 +43,10 @@ func roundUp(size int64) int64 {
 	return sectors * sectorSize
 }
 
-type targetImageType string
-
-const (
-	imageRaw  targetImageType = "raw"
-	imageASIF targetImageType = "ASIF"
-)
-
 // convertTo converts a source disk into a raw or ASIF disk.
 // source and dest may be same.
 // convertTo is a NOP if source == dest, and no resizing is needed.
-func convertTo(destType targetImageType, source, dest string, size *int64, allowSourceWithBackingFile bool) error {
+func convertTo(destType image.Type, source, dest string, size *int64, allowSourceWithBackingFile bool) error {
 	srcF, err := os.Open(source)
 	if err != nil {
 		return err
@@ -71,7 +65,7 @@ func convertTo(destType targetImageType, source, dest string, size *int64, allow
 		if err = srcF.Close(); err != nil {
 			return err
 		}
-		if destType == imageRaw {
+		if destType == raw.Type {
 			return convertRawToRaw(source, dest, size)
 		}
 	case qcow2.Type:
@@ -85,7 +79,7 @@ func convertTo(destType targetImageType, source, dest string, size *int64, allow
 			}
 		}
 	case asif.Type:
-		if destType == imageASIF {
+		if destType == asif.Type {
 			return convertASIFToASIF(source, dest, size)
 		}
 		return fmt.Errorf("conversion from ASIF to %q is not supported", destType)
@@ -103,10 +97,10 @@ func convertTo(destType targetImageType, source, dest string, size *int64, allow
 		attachedDevice string
 	)
 	switch destType {
-	case imageRaw:
+	case raw.Type:
 		destTmpF, err = os.CreateTemp(filepath.Dir(dest), filepath.Base(dest)+".lima-*.tmp")
 		destTmp = destTmpF.Name()
-	case imageASIF:
+	case asif.Type:
 		// destTmp != destTmpF.Name() because destTmpF is mounted ASIF device file.
 		randomBase := fmt.Sprintf("%s.lima-%d.tmp.asif", filepath.Base(dest), rand.UintN(math.MaxUint))
 		destTmp = filepath.Join(filepath.Dir(dest), randomBase)
@@ -150,7 +144,7 @@ func convertTo(destType targetImageType, source, dest string, size *int64, allow
 		return err
 	}
 	// Detach ASIF device
-	if destType == imageASIF {
+	if destType == asif.Type {
 		err := asifutil.DetachASIF(attachedDevice)
 		if err != nil {
 			return fmt.Errorf("failed to detach ASIF image %q: %w", attachedDevice, err)
@@ -230,7 +224,7 @@ func (n *NativeImageUtil) CreateDisk(_ context.Context, disk string, size int64)
 
 // ConvertToRaw converts a disk image to raw format.
 func (n *NativeImageUtil) ConvertToRaw(_ context.Context, source, dest string, size *int64, allowSourceWithBackingFile bool) error {
-	return convertTo(imageRaw, source, dest, size, allowSourceWithBackingFile)
+	return convertTo(raw.Type, source, dest, size, allowSourceWithBackingFile)
 }
 
 // ResizeDisk resizes an existing disk image to the specified size.
@@ -246,5 +240,5 @@ func (n *NativeImageUtil) MakeSparse(_ context.Context, f *os.File, offset int64
 
 // ConvertToASIF converts a disk image to ASIF format.
 func (n *NativeImageUtil) ConvertToASIF(_ context.Context, source, dest string, size *int64, allowSourceWithBackingFile bool) error {
-	return convertTo(imageASIF, source, dest, size, allowSourceWithBackingFile)
+	return convertTo(asif.Type, source, dest, size, allowSourceWithBackingFile)
 }

pkg/imgutil/nativeimgutil/nativeimgutil_test.go

@@ -11,6 +11,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/lima-vm/go-qcow2reader/image/raw"
 	"gotest.tools/v3/assert"
 )
 
@@ -65,15 +66,15 @@ func TestConvertToRaw(t *testing.T) {
 	t.Run("qcow without backing file", func(t *testing.T) {
 		resultImage := filepath.Join(tmpDir, strings.ReplaceAll(strings.ReplaceAll(t.Name(), string(os.PathSeparator), "_"), "/", "_"))
 
-		err = convertTo(imageRaw, qcowImage.Name(), resultImage, nil, false)
+		err = convertTo(raw.Type, qcowImage.Name(), resultImage, nil, false)
 		assert.NilError(t, err)
 		assertFileEquals(t, rawImage.Name(), resultImage)
 	})
 
 	t.Run("qcow with backing file", func(t *testing.T) {
 		resultImage := filepath.Join(tmpDir, strings.ReplaceAll(strings.ReplaceAll(t.Name(), string(os.PathSeparator), "_"), "/", "_"))
 
-		err = convertTo(imageRaw, qcowImage.Name(), resultImage, nil, true)
+		err = convertTo(raw.Type, qcowImage.Name(), resultImage, nil, true)
 		assert.NilError(t, err)
 		assertFileEquals(t, rawImage.Name(), resultImage)
 	})
@@ -82,15 +83,15 @@ func TestConvertToRaw(t *testing.T) {
 		resultImage := filepath.Join(tmpDir, strings.ReplaceAll(strings.ReplaceAll(t.Name(), string(os.PathSeparator), "_"), "/", "_"))
 
 		size := int64(2_097_152) // 2mb
-		err = convertTo(imageRaw, qcowImage.Name(), resultImage, &size, false)
+		err = convertTo(raw.Type, qcowImage.Name(), resultImage, &size, false)
 		assert.NilError(t, err)
 		assertFileEquals(t, rawImageExtended.Name(), resultImage)
 	})
 
 	t.Run("raw", func(t *testing.T) {
 		resultImage := filepath.Join(tmpDir, strings.ReplaceAll(strings.ReplaceAll(t.Name(), string(os.PathSeparator), "_"), "/", "_"))
 
-		err = convertTo(imageRaw, rawImage.Name(), resultImage, nil, false)
+		err = convertTo(raw.Type, rawImage.Name(), resultImage, nil, false)
 		assert.NilError(t, err)
 		assertFileEquals(t, rawImage.Name(), resultImage)
 	})

pkg/limatype/lima_yaml.go

@@ -7,6 +7,7 @@ import (
 	"net"
 	"runtime"
 
+	"github.com/lima-vm/go-qcow2reader/image"
 	"github.com/opencontainers/go-digest"
 	"github.com/sirupsen/logrus"
 	"golang.org/x/sys/cpu"
@@ -118,7 +119,8 @@ type QEMUOpts struct {
 }
 
 type VZOpts struct {
-	Rosetta Rosetta `yaml:"rosetta,omitempty" json:"rosetta,omitempty"`
+	Rosetta         Rosetta     `yaml:"rosetta,omitempty" json:"rosetta,omitempty"`
+	DiskImageFormat *image.Type `yaml:"diskImageFormat,omitempty" json:"diskImageFormat,omitempty" jsonschema:"nullable"`
 }
 
 type Rosetta struct {

pkg/limayaml/marshal_test.go

@@ -108,6 +108,7 @@ func TestVZOpts(t *testing.T) {
 vmType: "vz"
 vmOpts:
   vz:
+    diskImageFormat: null
     rosetta:
       enabled: null
       binfmt: null
@@ -148,6 +149,7 @@ func TestVZOptsRosettaMessage(t *testing.T) {
 vmType: "vz"
 vmOpts:
   vz:
+    diskImageFormat: "raw"
     rosetta:
       enabled: true
       binfmt: false
@@ -160,6 +162,7 @@ message: |
 	want := `vmType: vz
 vmOpts:
   vz:
+    diskImageFormat: raw
     rosetta:
       binfmt: false
       enabled: true

pkg/qemuimgutil/qemuimgutil.go

@@ -272,5 +272,5 @@ func AcceptableAsBaseDisk(info *Info) error {
 
 func (q *QemuImageUtil) ConvertToASIF(_ context.Context, _, _ string, _ *int64, _ bool) error {
 	// Should never be called because ASIF is not supported by qemu-img.
-	return nil
+	return errors.New("unimplemented")
 }

templates/default.yaml

@@ -370,6 +370,11 @@ vmOpts:
     #   riscv64: "max" # (or "host" when running on riscv64 host)
     #   x86_64:  "max" # (or "host" when running on x86_64 host; additional options are appended on Intel Mac)
   vz:
+    diskImageFormat: null
+    # Specify the disk image format: "raw" or "asif".
+    # Currently only applies to the primary disk image.
+    # "asif" requires macOS 26+, and does not support converting back to "raw".
+    # 🟢 Builtin default: "raw"
     rosetta:
       # Enable Rosetta inside the VM; needs `vmType: vz`
       # Hint: try `softwareupdate --install-rosetta` if Lima gets stuck at `Installing rosetta...`

website/content/en/docs/config/environment-variables.md

@@ -139,14 +139,6 @@ This page documents the environment variables used in Lima.
   ```sh
   export LIMA_USERNET_RESOLVE_IP_ADDRESS_TIMEOUT=5
   ```
-### `LIMA_VZ_ASIF`
-
-- **Description**: Specifies whether to use ASIF disk image format for VZ driver on macOS 26.0 or later.
-- **Default**: `false`
-- **Usage**: 
-  ```sh
-  export LIMA_VZ_ASIF=true
-  ```
 
 ### `_LIMA_QEMU_UEFI_IN_BIOS`