rust/crypto: Implement From<SymKeyType> for Nid

Implement `From<SymKeyType> for Nid`. This makes it easier to implement
generalized functions.
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>

rust/pv/src/crypto.rs

@@ -41,6 +41,15 @@ pub enum SymKeyType {
     Aes256Xts,
 }
 
+impl From<SymKeyType> for Nid {
+    fn from(value: SymKeyType) -> Self {
+        match value {
+            SymKeyType::Aes256 => Self::AES_256_GCM,
+            SymKeyType::Aes256Xts => Self::AES_256_XTS,
+        }
+    }
+}
+
 /// Types of symmetric keys
 #[non_exhaustive]
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -491,4 +500,16 @@ mod tests {
 
         assert_eq!(hmac, exp);
     }
+
+    #[test]
+    fn from_symkeytype() {
+        assert_eq!(
+            <SymKeyType as Into<Nid>>::into(SymKeyType::Aes256),
+            Nid::AES_256_GCM
+        );
+        assert_eq!(
+            <SymKeyType as Into<Nid>>::into(SymKeyType::Aes256Xts),
+            Nid::AES_256_XTS
+        );
+    }
 }