usbredir: make configurable redirecting usb devices

User can configure how many USB redirection devices to have in the
VMI by adding an empty clientPassthrough in the yaml, like:

 | spec:
 |   domain:
 |     devices:
 |       clientPassthrough: {}

KubeVirt will create the maximum value defined by
UsbClientPassthroughMaxNumberOf

Signed-off-by: Victor Toso <[email protected]>

pkg/virt-launcher/virtwrap/api/schema.go

@@ -439,6 +439,20 @@ type Devices struct {
 	Watchdog    *Watchdog          `xml:"watchdog,omitempty"`
 	Rng         *Rng               `xml:"rng,omitempty"`
 	Filesystems []FilesystemDevice `xml:"filesystem,omitempty"`
+	Redirs      []RedirectedDevice `xml:"redirdev,omitempty"`
+}
+
+// RedirectedDevice describes a device to be redirected
+// See: https://libvirt.org/formatdomain.html#redirected-devices
+type RedirectedDevice struct {
+	Type   string                 `xml:"type,attr"`
+	Bus    string                 `xml:"bus,attr"`
+	Source RedirectedDeviceSource `xml:"source"`
+}
+
+type RedirectedDeviceSource struct {
+	Mode string `xml:"mode,attr"`
+	Path string `xml:"path,attr"`
 }
 
 type FilesystemDevice struct {

pkg/virt-launcher/virtwrap/converter/converter.go

@@ -903,6 +903,33 @@ func Convert_v1_Rng_To_api_Rng(_ *v1.Rng, rng *api.Rng, c *ConverterContext) err
 	return nil
 }
 
+func Convert_v1_Usbredir_To_api_Usbredir(vmi *v1.VirtualMachineInstance, domainDevices *api.Devices, _ *ConverterContext) (bool, error) {
+	clientDevices := vmi.Spec.Domain.Devices.ClientPassthrough
+
+	// Default is to have USB Redirection disabled
+	if clientDevices == nil {
+		return false, nil
+	}
+
+	// Note that at the moment, we don't require any specific input to configure the USB devices
+	// so we simply create the maximum allowed dictated by v1.UsbClientPassthroughMaxNumberOf
+	redirectDevices := make([]api.RedirectedDevice, v1.UsbClientPassthroughMaxNumberOf)
+
+	for i := 0; i < v1.UsbClientPassthroughMaxNumberOf; i++ {
+		path := fmt.Sprintf("/var/run/kubevirt-private/%s/virt-usbredir-%d", vmi.ObjectMeta.UID, i)
+		redirectDevices[i] = api.RedirectedDevice{
+			Type: "unix",
+			Bus:  "usb",
+			Source: api.RedirectedDeviceSource{
+				Mode: "bind",
+				Path: path,
+			},
+		}
+	}
+	domainDevices.Redirs = redirectDevices
+	return true, nil
+}
+
 func Convert_v1_Input_To_api_InputDevice(input *v1.Input, inputDevice *api.Input) error {
 	if input.Bus != "virtio" && input.Bus != "usb" && input.Bus != "" {
 		return fmt.Errorf("input contains unsupported bus %s", input.Bus)
@@ -1507,6 +1534,11 @@ func Convert_v1_VirtualMachineInstance_To_api_Domain(vmi *v1.VirtualMachineInsta
 		domain.Spec.Devices.Inputs = inputDevices
 	}
 
+	isUSBRedirEnabled, err := Convert_v1_Usbredir_To_api_Usbredir(vmi, &domain.Spec.Devices, c)
+	if err != nil {
+		return err
+	}
+
 	domain.Spec.Devices.Ballooning = &api.MemBalloon{}
 	ConvertV1ToAPIBalloning(&vmi.Spec.Domain.Devices, domain.Spec.Devices.Ballooning, c)
 
@@ -1515,7 +1547,7 @@ func Convert_v1_VirtualMachineInstance_To_api_Domain(vmi *v1.VirtualMachineInsta
 	//In ppc64le usb devices like mouse / keyboard are set by default,
 	//so we can't disable the controller otherwise we run into the following error:
 	//"unsupported configuration: USB is disabled for this domain, but USB devices are present in the domain XML"
-	if !isUSBDevicePresent && c.Architecture != "ppc64le" {
+	if !isUSBDevicePresent && !isUSBRedirEnabled && c.Architecture != "ppc64le" {
 		// disable usb controller
 		domain.Spec.Devices.Controllers = append(domain.Spec.Devices.Controllers, api.Controller{
 			Type:  "usb",

pkg/virt-launcher/virtwrap/converter/converter_test.go

@@ -1749,6 +1749,30 @@ var _ = Describe("Converter", func() {
 			Expect(domain.Spec.Devices.Inputs[0].Bus).To(Equal("usb"), "Expect usb bus")
 		})
 
+		It("should enable usb redirection when number of USB client devices > 0", func() {
+			v1.SetObjectDefaults_VirtualMachineInstance(vmi)
+			vmi.Spec.Domain.Devices.ClientPassthrough = &v1.ClientPassthroughDevices{}
+			domain := vmiToDomain(vmi, c)
+			Expect(len(domain.Spec.Devices.Redirs)).To(Equal(4))
+			Expect(domain.Spec.Devices.Controllers).To(ContainElement(api.Controller{
+				Type:  "usb",
+				Index: "0",
+				Model: "qemu-xhci",
+			}))
+		})
+
+		It("should not enable usb redirection when numberOfDevices == 0", func() {
+			v1.SetObjectDefaults_VirtualMachineInstance(vmi)
+			vmi.Spec.Domain.Devices.ClientPassthrough = nil
+			domain := vmiToDomain(vmi, c)
+			Expect(domain.Spec.Devices.Redirs).To(BeNil())
+			Expect(domain.Spec.Devices.Controllers).ToNot(ContainElement(api.Controller{
+				Type:  "usb",
+				Index: "0",
+				Model: "qemu-xhci",
+			}))
+		})
+
 		It("should select explicitly chosen network model", func() {
 			v1.SetObjectDefaults_VirtualMachineInstance(vmi)
 			vmi.Spec.Domain.Devices.Interfaces[0].Model = "e1000"

staging/src/kubevirt.io/client-go/api/v1/schema.go

@@ -483,8 +483,28 @@ type Devices struct {
 	// +optional
 	// +listType=atomic
 	HostDevices []HostDevice `json:"hostDevices,omitempty"`
+	// To configure and access client devices such as redirecting USB
+	// +optional
+	ClientPassthrough *ClientPassthroughDevices `json:"clientPassthrough,omitempty"`
 }
 
+// Represent a subset of client devices that can be accessed by VMI. At the
+// moment only, USB devices using Usbredir's library and tooling. Another fit
+// would be a smartcard with libcacard.
+//
+// The struct is currently empty as there is no imediate request for
+// user-facing APIs. This structure simply turns on USB redirection of
+// UsbClientPassthroughMaxNumberOf devices.
+//
+// +k8s:openapi-gen=true
+type ClientPassthroughDevices struct {
+}
+
+// Represents the upper limit allowed by QEMU + KubeVirt.
+const (
+	UsbClientPassthroughMaxNumberOf = 4
+)
+
 //
 // +k8s:openapi-gen=true
 type Input struct {