Implement feature toggle for GA forwarding mode in QEMU

pkg/hostagent/hostagent.go

@@ -131,8 +131,9 @@ func New(instName string, stdout io.Writer, signalCh chan os.Signal, opts ...Opt
 		}
 		vSockPort = port
 	} else if *inst.Config.VMType == limayaml.QEMU {
-		// virtserialport doesn't seem to work reliably: https://github.com/lima-vm/lima/issues/2064
-		virtioPort = "" // filenames.VirtioPort
+		if *inst.Config.VMOpts.QEMU.VirtioGA {
+			virtioPort = filenames.VirtioPort
+		}
 	}
 
 	if err := cidata.GenerateCloudConfig(inst.Dir, instName, inst.Config); err != nil {

pkg/limayaml/defaults.go

@@ -835,6 +835,17 @@ func FillDefault(y, d, o *LimaYAML, filePath string, warn bool) {
 	caCerts := unique(append(append(d.CACertificates.Certs, y.CACertificates.Certs...), o.CACertificates.Certs...))
 	y.CACertificates.Certs = caCerts
 
+	if y.VMOpts.QEMU.VirtioGA == nil {
+		y.VMOpts.QEMU.VirtioGA = d.VMOpts.QEMU.VirtioGA
+	}
+	if o.VMOpts.QEMU.VirtioGA != nil {
+		y.VMOpts.QEMU.VirtioGA = o.VMOpts.QEMU.VirtioGA
+	}
+	if y.VMOpts.QEMU.VirtioGA == nil {
+		// virtserialport doesn't seem to work reliably, so, default to false: https://github.com/lima-vm/lima/issues/2064
+		y.VMOpts.QEMU.VirtioGA = ptr.Of(false)
+	}
+
 	if runtime.GOOS == "darwin" && IsNativeArch(AARCH64) {
 		if y.Rosetta.Enabled == nil {
 			y.Rosetta.Enabled = d.Rosetta.Enabled

pkg/limayaml/limayaml.go

@@ -98,6 +98,7 @@ type VMOpts struct {
 
 type QEMUOpts struct {
 	MinimumVersion *string `yaml:"minimumVersion,omitempty" json:"minimumVersion,omitempty" jsonschema:"nullable"`
+	VirtioGA       *bool   `yaml:"virtioGA,omitempty" json:"virtioGA,omitempty" jsonschema:"nullable"`
 }
 
 type Rosetta struct {

pkg/qemu/qemu.go

@@ -41,6 +41,7 @@ type Config struct {
 	InstanceDir  string
 	LimaYAML     *limayaml.LimaYAML
 	SSHLocalPort int
+	VirtioGA     bool
 }
 
 // MinimumQemuVersion is the minimum supported QEMU version.
@@ -920,11 +921,13 @@ func Cmdline(ctx context.Context, cfg Config) (exe string, args []string, err er
 	args = append(args, "-chardev", fmt.Sprintf("socket,id=%s,path=%s,server=on,wait=off", qmpChardev, qmpSock))
 	args = append(args, "-qmp", "chardev:"+qmpChardev)
 
-	// Guest agent via serialport
-	guestSock := filepath.Join(cfg.InstanceDir, filenames.GuestAgentSock)
-	args = append(args, "-chardev", fmt.Sprintf("socket,path=%s,server=on,wait=off,id=qga0", guestSock))
-	args = append(args, "-device", "virtio-serial")
-	args = append(args, "-device", "virtserialport,chardev=qga0,name="+filenames.VirtioPort)
+	if cfg.VirtioGA {
+		// Guest agent via serialport
+		guestSock := filepath.Join(cfg.InstanceDir, filenames.GuestAgentSock)
+		args = append(args, "-chardev", fmt.Sprintf("socket,path=%s,server=on,wait=off,id=qga0", guestSock))
+		args = append(args, "-device", "virtio-serial")
+		args = append(args, "-device", "virtserialport,chardev=qga0,name="+filenames.VirtioPort)
+	}
 
 	// QEMU process
 	args = append(args, "-name", "lima-"+cfg.Name)

pkg/qemu/qemu_driver.go

@@ -72,6 +72,7 @@ func (l *LimaQemuDriver) Start(ctx context.Context) (chan error, error) {
 		InstanceDir:  l.Instance.Dir,
 		LimaYAML:     l.Instance.Config,
 		SSHLocalPort: l.SSHLocalPort,
+		VirtioGA:     *l.Instance.Config.VMOpts.QEMU.VirtioGA,
 	}
 	qExe, qArgs, err := Cmdline(ctx, qCfg)
 	if err != nil {

templates/default.yaml

@@ -304,6 +304,10 @@
     # Will be ignored if the vmType is not "qemu"
     # 🟢 Builtin default: not set
     minimumVersion: null
+    # Enable virtio port for GA. If disabled then will forward GA via SSH.
+    # Will be ignored if the vmType is not "qemu"
+    # 🟢 Builtin default: false
+    virtioGA : null
 
 # OS: "Linux".
 # 🟢 Builtin default: "Linux"