vfkit: Use EFI bootloader

With the fixed iso, we can simplify the driver using the EFI bootloader
option[1] instead of the legacy and deprecated --kernel, --kernel-cmdline,
and --initrd options[2].

Example run:

    % minikube start -p vfkit --driver vfkit --container-runtime containerd --network vmnet-shared --iso-url file://$PWD/minikube-arm64-timeout-0.iso
    😄  [vfkit] minikube v1.36.0 on Darwin 15.5 (arm64)
    ✨  Using the vfkit driver based on user configuration
    👍  Starting "vfkit" primary control-plane node in "vfkit" cluster
    🔥  Creating vfkit VM (CPUs=2, Memory=6000MB, Disk=20000MB) ...
    📦  Preparing Kubernetes v1.33.1 on containerd 1.7.23 ...
        ▪ Generating certificates and keys ...
        ▪ Booting up control plane ...
        ▪ Configuring RBAC rules ...
    🔗  Configuring bridge CNI (Container Networking Interface) ...
    🔎  Verifying Kubernetes components...
        ▪ Using image gcr.io/k8s-minikube/storage-provisioner:v5
    🌟  Enabled addons: default-storageclass, storage-provisioner
    🏄  Done! kubectl is now configured to use "vfkit" cluster and "default" namespace by default

This avoids the need to extract the kernel and initrd. I expected to see
some speedup but direct kernel boot is little bit faster even including
the time to extract the kernel and initrd.

[1] https://github.com/crc-org/vfkit/blob/main/doc/usage.md#efi-bootloader
[2] https://github.com/crc-org/vfkit/blob/main/doc/usage.md#deprecated-options

Author: nirs

pkg/drivers/vfkit/vfkit.go

@@ -57,6 +57,7 @@ const (
 	pidFileName    = "vfkit.pid"
 	sockFilename   = "vfkit.sock"
 	logFileName    = "vfkig.log"
+	efiFileName    = "vfkit.efi"
 	defaultSSHUser = "docker"
 )
 
@@ -189,12 +190,6 @@ func (d *Driver) Create() error {
 	if err := b2dutils.CopyIsoToMachineDir(d.Boot2DockerURL, d.MachineName); err != nil {
 		return err
 	}
-	isoPath := d.ResolveStorePath(isoFilename)
-
-	log.Info("Extracting Kernel...")
-	if err := d.extractKernel(isoPath); err != nil {
-		return err
-	}
 
 	log.Info("Creating SSH key...")
 	if err := ssh.GenerateSSHKey(d.sshKeyPath()); err != nil {
@@ -256,9 +251,10 @@ func (d *Driver) startVfkit(socketPath string) error {
 		"--memory", fmt.Sprintf("%d", d.Memory),
 		"--cpus", fmt.Sprintf("%d", d.CPU),
 		"--restful-uri", fmt.Sprintf("unix://%s", d.sockfilePath()))
-	var isoPath = filepath.Join(machineDir, isoFilename)
+
+	efiPath := d.ResolveStorePath(efiFileName)
 	startCmd = append(startCmd,
-		"--device", fmt.Sprintf("virtio-blk,path=%s", isoPath))
+		"--bootloader", fmt.Sprintf("efi,variable-store=%s,create", efiPath))
 
 	if socketPath != "" {
 		// The guest will be able to access other guests in the vmnet network.
@@ -273,24 +269,18 @@ func (d *Driver) startVfkit(socketPath string) error {
 	startCmd = append(startCmd,
 		"--device", "virtio-rng")
 
+	var isoPath = filepath.Join(machineDir, isoFilename)
 	startCmd = append(startCmd,
-		"--kernel", d.ResolveStorePath("bzimage"))
-
-	// Required to enable logging to vfkit.log.
-	startCmd = append(startCmd,
-		"--kernel-cmdline", "console=hvc0")
+		"--device", fmt.Sprintf("virtio-blk,path=%s", isoPath))
 
 	startCmd = append(startCmd,
-		"--initrd", d.ResolveStorePath("initrd"))
+		"--device", fmt.Sprintf("virtio-blk,path=%s", d.diskPath()))
 
 	for i := 0; i < d.ExtraDisks; i++ {
 		startCmd = append(startCmd,
 			"--device", fmt.Sprintf("virtio-blk,path=%s", pkgdrivers.ExtraDiskPath(d.BaseDriver, i)))
 	}
 
-	startCmd = append(startCmd,
-		"--device", fmt.Sprintf("virtio-blk,path=%s", d.diskPath()))
-
 	logPath := d.ResolveStorePath(logFileName)
 	startCmd = append(startCmd,
 		"--device", fmt.Sprintf("virtio-serial,logFilePath=%s", logPath))
@@ -417,22 +407,6 @@ func (d *Driver) Restart() error {
 	return d.Start()
 }
 
-func (d *Driver) extractKernel(isoPath string) error {
-	for _, f := range []struct {
-		pathInIso string
-		destPath  string
-	}{
-		{"/boot/bzimage", "bzimage"},
-		{"/boot/initrd", "initrd"},
-	} {
-		fullDestPath := d.ResolveStorePath(f.destPath)
-		if err := pkgdrivers.ExtractFile(isoPath, f.pathInIso, fullDestPath); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
 func (d *Driver) killVfkit() error {
 	if err := d.SetVFKitState("HardStop"); err != nil {
 		// Typically fails with EOF due to https://github.com/crc-org/vfkit/issues/277.