gpu: Add ColdPlug of VFIO devices with devManager

If we have a VFIO device and cold-plug is enabled
we mark each device as ColdPlug=true and let the VFIO
module do the attaching.

Signed-off-by: Zvonko Kaiser <zkaiser@nvidia.com>

src/runtime/pkg/device/manager/manager.go

@@ -116,7 +116,7 @@ func (dm *deviceManager) createDevice(devInfo config.DeviceInfo) (dev api.Device
 	if devInfo.ID, err = dm.newDeviceID(); err != nil {
 		return nil, err
 	}
-	if isVFIO(devInfo.HostPath) {
+	if IsVFIO(devInfo.HostPath) {
 		return drivers.NewVFIODevice(&devInfo), nil
 	} else if isVhostUserBlk(devInfo) {
 		if devInfo.DriverOptions == nil {

src/runtime/pkg/device/manager/utils.go

@@ -17,8 +17,8 @@ const (
 	vfioPath = "/dev/vfio/"
 )
 
-// isVFIO checks if the device provided is a vfio group.
-func isVFIO(hostPath string) bool {
+// IsVFIO checks if the device provided is a vfio group.
+func IsVFIO(hostPath string) bool {
 	// Ignore /dev/vfio/vfio character device
 	if strings.HasPrefix(hostPath, filepath.Join(vfioPath, "vfio")) {
 		return false

src/runtime/pkg/device/manager/utils_test.go

@@ -31,7 +31,7 @@ func TestIsVFIO(t *testing.T) {
 	}
 
 	for _, d := range data {
-		isVFIO := isVFIO(d.path)
+		isVFIO := IsVFIO(d.path)
 		assert.Equal(t, d.expected, isVFIO)
 	}
 }