Add default value for audio driver

examples/README.md

@@ -56,6 +56,7 @@ Optional feature enablers:
 - [`experimental/net-user-v2`](./experimental/net-user-v2.yaml): [experimental] user-v2 network
   to enable VM-to-VM communication without root privilege
 - [`experimental/vnc`](./experimental/vnc.yaml): [experimental] use vnc display and xorg server
+- [`experimental/alsa`](./experimental/alsa.yaml): [experimental] use alsa and default audio device
 
 Lost+found:
 - ~`centos`~: Removed in Lima v0.8.0, as CentOS 8 reached [EOL](https://www.centos.org/centos-linux-eol/).

examples/default.yaml

@@ -297,6 +297,9 @@ audio:
   # QEMU audiodev, e.g., "none", "coreaudio", "pa", "alsa", "oss".
   # VZ driver, use "vz" as device name
   # Choosing "none" will mute the audio output, and not play any sound.
+  # Choosing "default" will pick a suitable of: coreudio, pa, dsound, oss.
+  # As of QEMU v6.2 the default is to create a disconnected sound device
+  # that is still visible in the guest but not connected to the host.
   # 🟢 Builtin default: ""
   device: null
 

examples/experimental/alsa.yaml

@@ -0,0 +1,55 @@
+# A template to run ubuntu using device: default
+# This template requires Lima v0.23.0 or later.
+images:
+# Try to use release-yyyyMMdd image if available. Note that release-yyyyMMdd will be removed after several months.
+- location: "https://cloud-images.ubuntu.com/releases/24.04/release-20240423/ubuntu-24.04-server-cloudimg-amd64.img"
+  arch: "x86_64"
+  digest: "sha256:32a9d30d18803da72f5936cf2b7b9efcb4d0bb63c67933f17e3bdfd1751de3f3"
+- location: "https://cloud-images.ubuntu.com/releases/24.04/release-20240423/ubuntu-24.04-server-cloudimg-arm64.img"
+  arch: "aarch64"
+  digest: "sha256:c841bac00925d3e6892d979798103a867931f255f28fefd9d5e07e3e22d0ef22"
+# Fallback to the latest release image.
+# Hint: run `limactl prune` to invalidate the cache
+- location: "https://cloud-images.ubuntu.com/releases/24.04/release/ubuntu-24.04-server-cloudimg-amd64.img"
+  arch: "x86_64"
+- location: "https://cloud-images.ubuntu.com/releases/24.04/release/ubuntu-24.04-server-cloudimg-arm64.img"
+  arch: "aarch64"
+
+mounts:
+- location: "~"
+- location: "/tmp/lima"
+  writable: true
+
+vmType: "qemu"
+audio:
+  device: "default"
+
+provision:
+- mode: system
+  script: |
+    #!/bin/bash
+    set -eux -o pipefail
+    test -e /lib/modules/$(uname -r)/kernel/sound/pci/hda/snd-hda-intel.ko* && exit 0
+    apt-get install -y linux-modules-extra-$(uname -r)
+    modprobe snd-hda-intel
+- mode: system
+  script: |
+    #!/bin/bash
+    set -eux -o pipefail
+    command -v aplay >/dev/null 2>&1 && exit 0
+    apt-get install -y --no-install-recommends alsa-utils
+probes:
+- description: "alsa to be installed"
+  script: |
+    #!/bin/bash
+    set -eux -o pipefail
+    if ! timeout 30s bash -c "until command -v aplay >/dev/null 2>&1; do sleep 3; done"; then
+      echo >&2 "alsa is not installed yet"
+      exit 1
+    fi
+  hint: See "/var/log/cloud-init-output.log" in the guest
+message: |
+  To get a list of all available audio devices:
+  $ sudo aplay -L
+  To test the audio device, use something like:
+  $ sudo speaker-test -c2 -twav

pkg/qemu/qemu.go

@@ -463,6 +463,19 @@ func qemuMachine(arch limayaml.Arch) string {
 	return "virt"
 }
 
+// audioDevice returns the default audio device.
+func audioDevice() string {
+	switch runtime.GOOS {
+	case "darwin":
+		return "coreaudio"
+	case "linux":
+		return "pa" // pulseaudio
+	case "windows":
+		return "dsound"
+	}
+	return "oss"
+}
+
 func Cmdline(ctx context.Context, cfg Config) (exe string, args []string, err error) {
 	y := cfg.LimaYAML
 	exe, args, err = Exe(*y.Arch)
@@ -762,6 +775,9 @@ func Cmdline(ctx context.Context, cfg Config) (exe string, args []string, err er
 		id := "default"
 		// audio device
 		audiodev := *y.Audio.Device
+		if audiodev == "default" {
+			audiodev = audioDevice()
+		}
 		audiodev += fmt.Sprintf(",id=%s", id)
 		args = append(args, "-audiodev", audiodev)
 		// audio controller

pkg/vz/vm_darwin.go

@@ -574,7 +574,8 @@ func attachFolderMounts(driver *driver.BaseDriver, vmConfig *vz.VirtualMachineCo
 }
 
 func attachAudio(driver *driver.BaseDriver, config *vz.VirtualMachineConfiguration) error {
-	if *driver.Yaml.Audio.Device == "vz" {
+	switch *driver.Yaml.Audio.Device {
+	case "vz", "default":
 		outputStream, err := vz.NewVirtioSoundDeviceHostOutputStreamConfiguration()
 		if err != nil {
 			return err
@@ -587,8 +588,12 @@ func attachAudio(driver *driver.BaseDriver, config *vz.VirtualMachineConfigurati
 		config.SetAudioDevicesVirtualMachineConfiguration([]vz.AudioDeviceConfiguration{
 			soundDeviceConfiguration,
 		})
+		return nil
+	case "", "none":
+		return nil
+	default:
+		return fmt.Errorf("unexpected audio device %q", *driver.Yaml.Audio.Device)
 	}
-	return nil
 }
 
 func attachOtherDevices(_ *driver.BaseDriver, vmConfig *vz.VirtualMachineConfiguration) error {

pkg/vz/vz_driver_darwin.go

@@ -131,9 +131,11 @@ func (l *LimaVzDriver) Validate() error {
 		}
 	}
 
-	audioDevice := *l.Yaml.Audio.Device
-	if audioDevice != "" && audioDevice != "vz" {
-		logrus.Warnf("field `audio.device` must be %q for VZ driver , got %q", "vz", audioDevice)
+	switch audioDevice := *l.Yaml.Audio.Device; audioDevice {
+	case "":
+	case "vz", "default", "none":
+	default:
+		logrus.Warnf("field `audio.device` must be \"vz\", \"default\", or \"none\" for VZ driver, got %q", audioDevice)
 	}
 
 	switch videoDisplay := *l.Yaml.Video.Display; videoDisplay {