subkernel: port master support

src/runtime/src/comms.rs

@@ -187,6 +187,22 @@ async fn handle_run_kernel(
 ) -> Result<()> {
     control.borrow_mut().tx.async_send(kernel::Message::StartRequest).await;
     loop {
+        #[cfg(has_drtio)]
+        while let Some(subkernel_finished) =
+            subkernel::get_finished_with_exception(aux_mutex, routing_table, timer).await?
+        {
+            if subkernel_finished.status == subkernel::FinishStatus::CommLost {
+                error!(
+                    "Communication with satellite lost while subkernel {} was running",
+                    subkernel_finished.id
+                );
+            }
+            if let Some(exception) = subkernel_finished.exception {
+                if let Some(stream) = stream {
+                    write_chunk(stream, &exception).await?;
+                }
+            }
+        }
         let reply = control.borrow_mut().rx.async_recv().await;
         match reply {
             kernel::Message::RpcSend { is_async, data } => {