virtcontainers: Revert "virtcontainers: Allow s390x appendVhostUserDevice"

This reverts commit 7f60911333.
Patch allowed other vhost user devices besides FS not supported on s390x
and failed to attach a CCW device number, which results in the
inavailability to use more devices after vhost-user-fs-ccw.

Signed-off-by: Jakob Naucke <jakob.naucke@ibm.com>

src/runtime/virtcontainers/qemu.go

@@ -1924,7 +1924,7 @@ func (q *qemu) addDevice(ctx context.Context, devInfo interface{}, devType devic
 			vhostDev.SocketPath = sockPath
 			vhostDev.DevID = id
 
-			q.qemuConfig.Devices = q.arch.appendVhostUserDevice(q.qemuConfig.Devices, vhostDev)
+			q.qemuConfig.Devices, err = q.arch.appendVhostUserDevice(q.qemuConfig.Devices, vhostDev)
 		} else {
 			q.Logger().WithField("volume-type", "virtio-9p").Info("adding volume")
 			q.qemuConfig.Devices, err = q.arch.append9PVolume(ctx, q.qemuConfig.Devices, v)
@@ -1939,7 +1939,7 @@ func (q *qemu) addDevice(ctx context.Context, devInfo interface{}, devType devic
 	case config.BlockDrive:
 		q.qemuConfig.Devices, err = q.arch.appendBlockDevice(ctx, q.qemuConfig.Devices, v)
 	case config.VhostUserDeviceAttrs:
-		q.qemuConfig.Devices = q.arch.appendVhostUserDevice(q.qemuConfig.Devices, v)
+		q.qemuConfig.Devices, err = q.arch.appendVhostUserDevice(q.qemuConfig.Devices, v)
 	case config.VFIODev:
 		q.qemuConfig.Devices = q.arch.appendVFIODevice(q.qemuConfig.Devices, v)
 	default:

src/runtime/virtcontainers/qemu_arch_base.go

@@ -96,7 +96,7 @@ type qemuArch interface {
 	appendBlockDevice(ctx context.Context, devices []govmmQemu.Device, drive config.BlockDrive) ([]govmmQemu.Device, error)
 
 	// appendVhostUserDevice appends a vhost user device to devices
-	appendVhostUserDevice(devices []govmmQemu.Device, drive config.VhostUserDeviceAttrs) []govmmQemu.Device
+	appendVhostUserDevice(devices []govmmQemu.Device, drive config.VhostUserDeviceAttrs) ([]govmmQemu.Device, error)
 
 	// appendVFIODevice appends a VFIO device to devices
 	appendVFIODevice(devices []govmmQemu.Device, vfioDevice config.VFIODev) []govmmQemu.Device
@@ -633,7 +633,7 @@ func (q *qemuArchBase) appendBlockDevice(_ context.Context, devices []govmmQemu.
 	return devices, nil
 }
 
-func (q *qemuArchBase) appendVhostUserDevice(devices []govmmQemu.Device, attr config.VhostUserDeviceAttrs) []govmmQemu.Device {
+func (q *qemuArchBase) appendVhostUserDevice(devices []govmmQemu.Device, attr config.VhostUserDeviceAttrs) ([]govmmQemu.Device, error) {
 	qemuVhostUserDevice := govmmQemu.VhostUserDevice{}
 
 	switch attr.Type {
@@ -658,7 +658,7 @@ func (q *qemuArchBase) appendVhostUserDevice(devices []govmmQemu.Device, attr co
 
 	devices = append(devices, qemuVhostUserDevice)
 
-	return devices
+	return devices, nil
 }
 
 func (q *qemuArchBase) appendVFIODevice(devices []govmmQemu.Device, vfioDev config.VFIODev) []govmmQemu.Device {

src/runtime/virtcontainers/qemu_arch_base_test.go

@@ -224,7 +224,7 @@ func testQemuArchBaseAppend(t *testing.T, structure interface{}, expected []govm
 	case config.VFIODev:
 		devices = qemuArchBase.appendVFIODevice(devices, s)
 	case config.VhostUserDeviceAttrs:
-		devices = qemuArchBase.appendVhostUserDevice(devices, s)
+		devices, err = qemuArchBase.appendVhostUserDevice(devices, s)
 	}
 
 	assert.NoError(err)

src/runtime/virtcontainers/qemu_s390x.go

@@ -152,6 +152,12 @@ func (q *qemuS390x) appendCCWBlockDevice(ctx context.Context, devices []govmmQem
 	return devices, nil
 }
 
+// appendVhostUserDevice throws an error if vhost devices are tried to be used.
+// See issue https://github.com/kata-containers/runtime/issues/659
+func (q *qemuS390x) appendVhostUserDevice(devices []govmmQemu.Device, attr config.VhostUserDeviceAttrs) ([]govmmQemu.Device, error) {
+	return nil, fmt.Errorf("No vhost-user devices supported on s390x")
+}
+
 // supportGuestMemoryHotplug return false for s390x architecture. The pc-dimm backend device for s390x
 // is not support. PC-DIMM is not listed in the devices supported by qemu-system-s390x -device help
 func (q *qemuS390x) supportGuestMemoryHotplug() bool {

src/runtime/virtcontainers/qemu_s390x_test.go

@@ -52,3 +52,17 @@ func TestQemuS390xMemoryTopology(t *testing.T) {
 	m := s390x.memoryTopology(mem, hostMem, slots)
 	assert.Equal(expectedMemory, m)
 }
+
+func TestQemuS390xAppendVhostUserDevice(t *testing.T) {
+	macAddress := "00:11:22:33:44:55:66"
+	qemu := qemuS390x{}
+	assert := assert.New(t)
+
+	vhostUserDevice := config.VhostUserDeviceAttrs{
+		Type:       config.VhostUserNet,
+		MacAddress: macAddress,
+	}
+
+	_, err := qemu.appendVhostUserDevice(nil, vhostUserDevice)
+	assert.Error(err)
+}