vmm: Error for PciDeviceError and PciRootError

Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>

On-behalf-of: SAP <philipp.schuster@sap.com>

vm-device/src/bus.rs

@@ -10,7 +10,9 @@
 use std::cmp::Ordering;
 use std::collections::btree_map::BTreeMap;
 use std::sync::{Arc, Barrier, Mutex, RwLock, Weak};
-use std::{convert, error, fmt, io, result};
+use std::{convert, io, result};
+
+use thiserror::Error;
 
 /// Trait for devices that respond to reads or writes in an arbitrary address space.
 ///
@@ -51,26 +53,21 @@ impl<B: BusDevice> BusDeviceSync for Mutex<B> {
     }
 }
 
-#[derive(Debug)]
+#[derive(Error, Debug)]
 pub enum Error {
     /// The insertion failed because the new device overlapped with an old device.
+    #[error("The insertion failed because the new device overlapped with an old device")]
     Overlap,
     /// Failed to operate on zero sized range.
+    #[error("Failed to operate on zero sized range")]
     ZeroSizedRange,
     /// Failed to find address range.
+    #[error("Failed to find address range")]
     MissingAddressRange,
 }
 
 pub type Result<T> = result::Result<T, Error>;
 
-impl fmt::Display for Error {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "bus_error: {self:?}")
-    }
-}
-
-impl error::Error for Error {}
-
 impl convert::From<Error> for io::Error {
     fn from(e: Error) -> Self {
         io::Error::other(e)