Add nvpci.Interface to the nvmdev struct to aid in unit tests

Signed-off-by: Christopher Desiniotis <cdesiniotis@nvidia.com>

pkg/nvmdev/mock.go

@@ -28,6 +28,7 @@ import (
 // MockNvmdev mock mdev device.
 type MockNvmdev struct {
 	*nvmdev
+	pciDevicesRoot string
 }
 
 var _ Interface = (*MockNvmdev)(nil)
@@ -53,8 +54,24 @@ func NewMock() (mock *MockNvmdev, rerr error) {
 		}
 	}()
 
+	pciRootDir, err := os.MkdirTemp(os.TempDir(), "")
+	if err != nil {
+		return nil, err
+	}
+	defer func() {
+		if rerr != nil {
+			os.RemoveAll(pciRootDir)
+		}
+	}()
+
+	nvpciLib := nvpci.New(nvpci.WithPCIDevicesRoot(pciRootDir))
 	mock = &MockNvmdev{
-		&nvmdev{mdevParentsRootDir, mdevDevicesRootDir},
+		nvmdev: &nvmdev{
+			mdevParentsRoot: mdevParentsRootDir,
+			mdevDevicesRoot: mdevDevicesRootDir,
+			nvpci:           nvpciLib,
+		},
+		pciDevicesRoot: pciRootDir,
 	}
 
 	return mock, nil
@@ -64,12 +81,20 @@ func NewMock() (mock *MockNvmdev, rerr error) {
 func (m *MockNvmdev) Cleanup() {
 	os.RemoveAll(m.mdevParentsRoot)
 	os.RemoveAll(m.mdevDevicesRoot)
+	os.RemoveAll(m.pciDevicesRoot)
 }
 
 // AddMockA100Parent creates an A100 like parent GPU mock device.
 func (m *MockNvmdev) AddMockA100Parent(address string, numaNode int) error {
+	pciDeviceDir := filepath.Join(m.pciDevicesRoot, address)
+	err := os.MkdirAll(pciDeviceDir, 0755)
+	if err != nil {
+		return err
+	}
+
+	// /sys/class/mdev_bus/<address> is a symlink to /sys/bus/pci/devices/<address>
 	deviceDir := filepath.Join(m.mdevParentsRoot, address)
-	err := os.MkdirAll(deviceDir, 0755)
+	err = os.Symlink(pciDeviceDir, deviceDir)
 	if err != nil {
 		return err
 	}

pkg/nvmdev/nvmdev.go

@@ -42,6 +42,7 @@ type Interface interface {
 type nvmdev struct {
 	mdevParentsRoot string
 	mdevDevicesRoot string
+	nvpci           nvpci.Interface
 }
 
 var _ Interface = (*nvmdev)(nil)
@@ -63,8 +64,25 @@ type Device struct {
 }
 
 // New interface that allows us to get a list of all NVIDIA parent and MDEV (vGPU) devices.
-func New() Interface {
-	return &nvmdev{mdevParentsRoot, mdevDevicesRoot}
+func New(opts ...Option) Interface {
+	n := &nvmdev{mdevParentsRoot: mdevParentsRoot, mdevDevicesRoot: mdevDevicesRoot}
+	for _, opt := range opts {
+		opt(n)
+	}
+	if n.nvpci == nil {
+		n.nvpci = nvpci.New()
+	}
+	return n
+}
+
+// Option defines a function for passing options to the New() call.
+type Option func(*nvmdev)
+
+// WithNvpciLib provides an Option to set the nvpci library.
+func WithNvpciLib(nvpciLib nvpci.Interface) Option {
+	return func(n *nvmdev) {
+		n.nvpci = nvpciLib
+	}
 }
 
 // GetAllParentDevices returns all NVIDIA Parent PCI devices on the system.
@@ -77,7 +95,7 @@ func (m *nvmdev) GetAllParentDevices() ([]*ParentDevice, error) {
 	var nvdevices []*ParentDevice
 	for _, deviceDir := range deviceDirs {
 		devicePath := path.Join(m.mdevParentsRoot, deviceDir.Name())
-		nvdevice, err := NewParentDevice(devicePath)
+		nvdevice, err := m.NewParentDevice(devicePath)
 		if err != nil {
 			return nil, fmt.Errorf("error constructing NVIDIA parent device: %v", err)
 		}
@@ -110,7 +128,7 @@ func (m *nvmdev) GetAllDevices() ([]*Device, error) {
 
 	var nvdevices []*Device
 	for _, deviceDir := range deviceDirs {
-		nvdevice, err := NewDevice(m.mdevDevicesRoot, deviceDir.Name())
+		nvdevice, err := m.NewDevice(m.mdevDevicesRoot, deviceDir.Name())
 		if err != nil {
 			return nil, fmt.Errorf("error constructing MDEV device: %v", err)
 		}
@@ -124,7 +142,7 @@ func (m *nvmdev) GetAllDevices() ([]*Device, error) {
 }
 
 // NewDevice constructs a Device, which represents an NVIDIA mdev (vGPU) device.
-func NewDevice(root string, uuid string) (*Device, error) {
+func (n *nvmdev) NewDevice(root string, uuid string) (*Device, error) {
 	path := path.Join(root, uuid)
 
 	m, err := newMdev(path)
@@ -132,7 +150,7 @@ func NewDevice(root string, uuid string) (*Device, error) {
 		return nil, err
 	}
 
-	parent, err := NewParentDevice(m.parentDevicePath())
+	parent, err := n.NewParentDevice(m.parentDevicePath())
 	if err != nil {
 		return nil, fmt.Errorf("error constructing NVIDIA PCI device: %v", err)
 	}
@@ -241,9 +259,9 @@ func (m mdev) iommuGroup() (int, error) {
 }
 
 // NewParentDevice constructs a ParentDevice.
-func NewParentDevice(devicePath string) (*ParentDevice, error) {
+func (m *nvmdev) NewParentDevice(devicePath string) (*ParentDevice, error) {
 	address := filepath.Base(devicePath)
-	nvdevice, err := nvpci.New().GetGPUByPciBusID(address)
+	nvdevice, err := m.nvpci.GetGPUByPciBusID(address)
 	if err != nil {
 		return nil, fmt.Errorf("failed to construct NVIDIA PCI device: %v", err)
 	}