sound: extend SoundConfig with output/input enabled flags

Add output_enabled and input_enabled boolean fields to SoundConfig,
with has_output() and has_input() accessors. Wire up the --streams CLI
arg so that SoundConfig reflects which directions the user requested.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

vhost-device-sound/src/device.rs

@@ -735,7 +735,7 @@ mod tests {
     #[test]
     fn test_sound_thread_success() {
         crate::init_logger();
-        let config = SoundConfig::new(false, BackendType::Null);
+        let config = SoundConfig::new(false, BackendType::Null, true, true);
 
         let chmaps = Arc::new(RwLock::new(vec![]));
         let jacks = Arc::new(RwLock::new(vec![]));
@@ -845,7 +845,7 @@ mod tests {
     #[test]
     fn test_sound_thread_failure() {
         crate::init_logger();
-        let config = SoundConfig::new(false, BackendType::Null);
+        let config = SoundConfig::new(false, BackendType::Null, true, true);
 
         let chmaps = Arc::new(RwLock::new(vec![]));
         let jacks = Arc::new(RwLock::new(vec![]));
@@ -934,7 +934,7 @@ mod tests {
     fn test_sound_backend() {
         crate::init_logger();
         let test_dir = tempdir().expect("Could not create a temp test directory.");
-        let config = SoundConfig::new(false, BackendType::Null);
+        let config = SoundConfig::new(false, BackendType::Null, true, true);
         let backend = VhostUserSoundBackend::new(config).expect("Could not create backend.");
 
         assert_eq!(backend.num_queues(), NUM_QUEUES as usize);
@@ -1012,7 +1012,7 @@ mod tests {
         crate::init_logger();
         let test_dir = tempdir().expect("Could not create a temp test directory.");
 
-        let config = SoundConfig::new(false, BackendType::Null);
+        let config = SoundConfig::new(false, BackendType::Null, true, true);
         let backend = VhostUserSoundBackend::new(config);
 
         let backend = backend.unwrap();

vhost-device-sound/src/lib.rs

@@ -216,21 +216,40 @@ pub struct SoundConfig {
     multi_thread: bool,
     /// audio backend variant
     audio_backend: BackendType,
+    /// enable output (playback) streams
+    output_enabled: bool,
+    /// enable input (capture) streams
+    input_enabled: bool,
 }
 
 impl SoundConfig {
     /// Create a new instance of the SoundConfig struct, containing the
     /// parameters to be fed into the sound-backend server.
-    pub const fn new(multi_thread: bool, audio_backend: BackendType) -> Self {
+    pub const fn new(
+        multi_thread: bool,
+        audio_backend: BackendType,
+        output_enabled: bool,
+        input_enabled: bool,
+    ) -> Self {
         Self {
             multi_thread,
             audio_backend,
+            output_enabled,
+            input_enabled,
         }
     }
 
     pub const fn get_audio_backend(&self) -> BackendType {
         self.audio_backend
     }
+
+    pub const fn has_output(&self) -> bool {
+        self.output_enabled
+    }
+
+    pub const fn has_input(&self) -> bool {
+        self.input_enabled
+    }
 }
 
 pub struct IOMessage {
@@ -332,7 +351,7 @@ mod tests {
     fn test_sound_server() {
         crate::init_logger();
 
-        let config = SoundConfig::new(false, BackendType::Null);
+        let config = SoundConfig::new(false, BackendType::Null, true, true);
 
         let backend = Arc::new(VhostUserSoundBackend::new(config).unwrap());
         let daemon = VhostUserDaemon::new(
@@ -433,4 +452,19 @@ mod tests {
         let stream_error = stream::Error::DescriptorReadFailed;
         let _error: Error = stream_error.into();
     }
+
+    #[test]
+    fn test_sound_config_stream_directions() {
+        let config = SoundConfig::new(false, BackendType::Null, true, true);
+        assert!(config.has_output());
+        assert!(config.has_input());
+
+        let config = SoundConfig::new(false, BackendType::Null, true, false);
+        assert!(config.has_output());
+        assert!(!config.has_input());
+
+        let config = SoundConfig::new(false, BackendType::Null, false, true);
+        assert!(!config.has_output());
+        assert!(config.has_input());
+    }
 }

vhost-device-sound/src/main.rs

@@ -7,13 +7,15 @@ use std::os::unix::prelude::*;
 
 use clap::Parser;
 use vhost::vhost_user::Listener;
-use vhost_device_sound::{args::SoundArgs, start_backend_server, SoundConfig};
+use vhost_device_sound::{args, args::SoundArgs, start_backend_server, SoundConfig};
 
 fn main() {
     env_logger::init();
 
     let args = SoundArgs::parse();
-    let config = SoundConfig::new(false, args.backend);
+    let has_output = args.streams.contains(&args::StreamDirection::Output);
+    let has_input = args.streams.contains(&args::StreamDirection::Input);
+    let config = SoundConfig::new(false, args.backend, has_output, has_input);
 
     let mut listener = if let Some(fd) = args.socket_fd {
         // SAFETY: user has assured us this is safe.
@@ -181,7 +183,7 @@ mod tests {
             backend_name,
         ]);
 
-        let config = SoundConfig::new(false, args.backend);
+        let config = SoundConfig::new(false, args.backend, true, true);
         assert_eq!(config.get_audio_backend(), backend);
     }
 }