diff --git a/proxmox/config_qemu_usb.go b/proxmox/config_qemu_usb.go
index 447aaa5a..8b9423ab 100644
--- a/proxmox/config_qemu_usb.go
+++ b/proxmox/config_qemu_usb.go
@@ -325,7 +325,7 @@ func (id UsbDeviceID) String() string {
 type UsbPortID string // regex: \d+-\d+
 
 const (
-	UsbPortID_Error_Invalid string = "invalid usb port id"
+	UsbPortID_Error_Invalid string = "invalid usb port id. Expected expression of the form '<bus>-<port>(.<port>)*' where bus and port are integers"
 )
 
 func (id UsbPortID) String() string {
@@ -340,8 +340,11 @@ func (id UsbPortID) Validate() error {
 	if _, err := strconv.Atoi(idArray[0]); err != nil {
 		return errors.New(UsbPortID_Error_Invalid)
 	}
-	if _, err := strconv.Atoi(idArray[1]); err != nil {
-		return errors.New(UsbPortID_Error_Invalid)
+	parts := strings.Split(idArray[1], ".")
+	for _, part := range parts {
+		if _, err := strconv.Atoi(part); err != nil {
+			return errors.New(UsbPortID_Error_Invalid)
+		}
 	}
 	return nil
 }
diff --git a/proxmox/config_qemu_usb_test.go b/proxmox/config_qemu_usb_test.go
index f51cd129..4cc30ddb 100644
--- a/proxmox/config_qemu_usb_test.go
+++ b/proxmox/config_qemu_usb_test.go
@@ -172,6 +172,10 @@ func Test_UsbPortID_Validate(t *testing.T) {
 	}{
 		{name: "Valid",
 			input: "2-4"},
+		{name: "Valid",
+			input: "2-4.1"},
+		{name: "Valid",
+			input: "3-1.2.3.4.5.6.7.8.9"},
 		// Invalid
 		{name: "UsbPortID_Error_Invalid",
 			input:  "2-4-5",