Implement disable default mounts via command line

Signed-off-by: Arthur Sengileyev <arthur.sengileyev@gmail.com>

pkg/machine/e2e/basic_test.go

@@ -117,6 +117,33 @@ var _ = Describe("run basic podman commands", func() {
 		Expect(findmnt.outputToString()).To(ContainSubstring("virtiofs"))
 	})
 
+	It("Volume should be disabled by command line", func() {
+		skipIfWSL("Requires standard volume handling")
+		skipIfVmtype(define.AppleHvVirt, "Skipped on Apple platform")
+		skipIfVmtype(define.LibKrun, "Skipped on Apple platform")
+
+		name := randomString()
+		i := new(initMachine).withImage(mb.imagePath).withNow()
+
+		// Empty arg forces no volumes
+		i.withVolume("")
+		session, err := mb.setName(name).setCmd(i).run()
+		Expect(err).ToNot(HaveOccurred())
+		Expect(session).To(Exit(0))
+
+		ssh9p := new(sshMachine).withSSHCommand([]string{"findmnt", "-no", "FSTYPE", "-t", "9p"})
+		findmnt9p, err := mb.setName(name).setCmd(ssh9p).run()
+		Expect(err).ToNot(HaveOccurred())
+		Expect(findmnt9p).To(Exit(0))
+		Expect(findmnt9p.outputToString()).To(BeEmpty())
+
+		sshVirtiofs := new(sshMachine).withSSHCommand([]string{"findmnt", "-no", "FSTYPE", "-t", "virtiofs"})
+		findmntVirtiofs, err := mb.setName(name).setCmd(sshVirtiofs).run()
+		Expect(err).ToNot(HaveOccurred())
+		Expect(findmntVirtiofs).To(Exit(0))
+		Expect(findmntVirtiofs.outputToString()).To(BeEmpty())
+	})
+
 	It("Podman ops with port forwarding and gvproxy", func() {
 		name := randomString()
 		i := new(initMachine)

pkg/machine/qemu/stubber.go

@@ -168,9 +168,13 @@ func (q *QEMUStubber) StartVM(mc *vmconfigs.MachineConfig) (func() error, func()
 	if err != nil {
 		return nil, nil, err
 	}
-	spawner, err := newVirtiofsdSpawner(runtime)
+
-	if err != nil {
+	var spawner *virtiofsdSpawner
-		return nil, nil, err
+	if len(mc.Mounts) > 0 {
+		spawner, err = newVirtiofsdSpawner(runtime)
+		if err != nil {
+			return nil, nil, err
+		}
 	}
 
 	for _, hostmnt := range mc.Mounts {

pkg/machine/shim/volume.go

@@ -8,6 +8,9 @@ import (
 func CmdLineVolumesToMounts(volumes []string, volumeType vmconfigs.VolumeMountType) []*vmconfigs.Mount {
 	mounts := []*vmconfigs.Mount{}
 	for i, volume := range volumes {
+		if volume == "" {
+			continue
+		}
 		var mount vmconfigs.Mount
 		tag, source, target, readOnly, _ := vmconfigs.SplitVolume(i, volume)
 		switch volumeType {