vmm: For --disk error if socket and path is specified

This is an error as the path should be specfied by the unmanaged
backend.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

vmm/src/config.rs

@@ -49,6 +49,8 @@ pub enum Error {
     ParseDiskVhostParam(std::str::ParseBoolError),
     /// Failed parsing disk wce parameter.
     ParseDiskWceParam(std::str::ParseBoolError),
+    /// Both socket and path specified
+    ParseDiskSocketAndPath,
     /// Failed parsing random number generator parameters.
     ParseRngParams,
     /// Failed parsing network ip parameter.
@@ -453,6 +455,10 @@ impl DiskConfig {
             path = Some(PathBuf::from(path_str))
         }
 
+        if vhost_socket.as_ref().and(path.as_ref()).is_some() {
+            return Err(Error::ParseDiskSocketAndPath);
+        }
+
         Ok(DiskConfig {
             path,
             readonly: parse_on_off(readonly_str)?,