helper function to standardize the PCIBusID device attribute for DRA drivers

Signed-off-by: Varun Ramachandra Sekar <vsekar@nvidia.com>

staging/src/k8s.io/dynamic-resource-allocation/deviceattribute/attribute.go

@@ -30,6 +30,13 @@ const (
 	// referring to a PCIe (Peripheral Component Interconnect Express) Root Complex.
 	// This attribute can be used to identify devices that share the same PCIe Root Complex.
 	StandardDeviceAttributePCIeRoot resourceapi.QualifiedName = StandardDeviceAttributePrefix + "pcieRoot"
+
+	// StandardDeviceAttributePCIBusID is a standard device attribute name
+	// which describes the PCI Bus address of the PCI device.
+	// The value is a string value in the extended BDF notation (Domain:Bus:Device.Function),
+	// referring to a PCI (Peripheral Component Interconnect) device.
+	// This attribute can be used to identify PCI devices.
+	StandardDeviceAttributePCIBusID resourceapi.QualifiedName = StandardDeviceAttributePrefix + "pciBusID"
 )
 
 // DeviceAttribute represents a device attribute name and its value

staging/src/k8s.io/dynamic-resource-allocation/deviceattribute/pci_linux.go

@@ -34,13 +34,8 @@ import (
 //
 // ref: https://wiki.xenproject.org/wiki/Bus:Device.Function_(BDF)_Notation
 func GetPCIeRootAttributeByPCIBusID(pciBusID string) (DeviceAttribute, error) {
-	if pciBusID == "" {
-		return DeviceAttribute{}, fmt.Errorf("PCI Bus ID cannot be empty")
-	}
-
-	bdfRegexp := regexp.MustCompile(`^([0-9a-f]{4}):([0-9a-f]{2}):([0-9a-f]{2})\.([0-9a-f]{1})$`)
-	if !bdfRegexp.MatchString(pciBusID) {
-		return DeviceAttribute{}, fmt.Errorf("invalid PCI Bus ID format: %s", pciBusID)
+	if err := verifyPCIBDFFormat(pciBusID); err != nil {
+		return DeviceAttribute{}, err
 	}
 
 	pcieRoot, err := resolvePCIeRoot(pciBusID)
@@ -100,3 +95,39 @@ func resolvePCIeRoot(pciBusID string) (string, error) {
 
 	return pcieRootPart, nil
 }
+
+// GetPCIBusIDAttribute returns a DeviceAttribute with the PCI Bus Address("<domain>:<bus>:<device>.<function>")
+// of a PCI device as a string value.
+//
+// It returns an error if the PCI Bus ID is empty or is not in
+// extended BDF (Domain:Bus:Device.Function) format, e.g., "0123:45:1e.7"
+//
+// ref: https://wiki.xenproject.org/wiki/Bus:Device.Function_(BDF)_Notation
+func GetPCIBusIDAttribute(pciBusID string) (DeviceAttribute, error) {
+	if err := verifyPCIBDFFormat(pciBusID); err != nil {
+		return DeviceAttribute{}, err
+	}
+
+	attr := DeviceAttribute{
+		Name:  StandardDeviceAttributePCIBusID,
+		Value: resourceapi.DeviceAttribute{StringValue: &pciBusID},
+	}
+
+	return attr, nil
+}
+
+// verifyPCIBDFFormat verifies that the PCI Bus ID is in extended BDF (Domain:Bus:Device.Function) format.
+//
+// ref: https://wiki.xenproject.org/wiki/Bus:Device.Function_(BDF)_Notation
+func verifyPCIBDFFormat(pciBusID string) error {
+	if pciBusID == "" {
+		return fmt.Errorf("PCI Bus ID cannot be empty")
+	}
+
+	bdfRegexp := regexp.MustCompile(`^([0-9a-f]{4}):([0-9a-f]{2}):([0-9a-f]{2})\.([0-9a-f]{1})$`)
+	if !bdfRegexp.MatchString(pciBusID) {
+		return fmt.Errorf("invalid PCI Bus ID format: %s", pciBusID)
+	}
+
+	return nil
+}

staging/src/k8s.io/dynamic-resource-allocation/deviceattribute/pci_linux_test.go

@@ -136,6 +136,61 @@ func TestGetPCIeRootAttributePCIBusID(t *testing.T) {
 	}
 }
 
+func TestGetPCIBusIDAttribute(t *testing.T) {
+	pciBusID := "0000:02:00.0"
+	expectedAttribute := DeviceAttribute{
+		Name:  StandardDeviceAttributePCIBusID,
+		Value: resourceapi.DeviceAttribute{StringValue: ptr.To(pciBusID)},
+	}
+
+	tests := map[string]struct {
+		address           string
+		expectedAttribute *DeviceAttribute
+		expectsError      bool
+		expectedErrMsg    string
+	}{
+		"valid": {
+			address:           pciBusID,
+			expectedAttribute: &expectedAttribute,
+			expectsError:      false,
+		},
+		"invalid empty PCI Bus ID": {
+			address:           "",
+			expectedAttribute: nil,
+			expectsError:      true,
+			expectedErrMsg:    "PCI Bus ID cannot be empty",
+		},
+		"invalid PCI Bus ID format": {
+			address:           "invalid-pci-id",
+			expectedAttribute: nil,
+			expectsError:      true,
+			expectedErrMsg:    "invalid PCI Bus ID format: invalid-pci-id",
+		},
+	}
+	for name, test := range tests {
+		t.Run(name, func(t *testing.T) {
+			got, err := GetPCIBusIDAttribute(test.address)
+			if test.expectsError {
+				if err == nil {
+					t.Errorf("Expected error but got none")
+					return
+				}
+				if !strings.Contains(err.Error(), test.expectedErrMsg) {
+					t.Errorf("Expected error message to contain %q, got %q", test.expectedErrMsg, err.Error())
+					return
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("Unexpected error: %v", err)
+			}
+			if !reflect.DeepEqual(got, *test.expectedAttribute) {
+				t.Errorf("Expected attribute %v, got %v", test.expectedAttribute, got)
+			}
+		})
+	}
+}
+
 func touchFile(t *testing.T, path string) {
 	t.Helper()
 	if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {