vmm: Implement InterruptSourceGroup and InterruptManager skeleton

This commit introduces an empty implementation of both InterruptManager
and InterruptSourceGroup traits, as a proper basis for further
implementation.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

vmm/src/interrupt.rs

@@ -0,0 +1,48 @@
+// Copyright © 2019 Intel Corporation
+//
+// SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause
+//
+
+use std::sync::Arc;
+use vm_device::interrupt::{
+    InterruptIndex, InterruptManager, InterruptSourceConfig, InterruptSourceGroup, InterruptType,
+};
+
+/// Reuse std::io::Result to simplify interoperability among crates.
+pub type Result<T> = std::io::Result<T>;
+
+pub struct MsiInterruptGroup {}
+
+impl MsiInterruptGroup {
+    fn new() -> Self {
+        MsiInterruptGroup {}
+    }
+}
+
+impl InterruptSourceGroup for MsiInterruptGroup {
+    fn trigger(&self, _index: InterruptIndex) -> Result<()> {
+        Ok(())
+    }
+
+    fn update(&self, _index: InterruptIndex, _config: InterruptSourceConfig) -> Result<()> {
+        Ok(())
+    }
+}
+
+pub struct KvmInterruptManager {}
+
+impl InterruptManager for KvmInterruptManager {
+    fn create_group(
+        &self,
+        _interrupt_type: InterruptType,
+        _base: InterruptIndex,
+        _count: InterruptIndex,
+    ) -> Result<Arc<Box<dyn InterruptSourceGroup>>> {
+        let interrupt_source_group = MsiInterruptGroup::new();
+        Ok(Arc::new(Box::new(interrupt_source_group)))
+    }
+
+    fn destroy_group(&self, _group: Arc<Box<dyn InterruptSourceGroup>>) -> Result<()> {
+        Ok(())
+    }
+}

vmm/src/lib.rs

@@ -30,6 +30,7 @@ pub mod api;
 pub mod config;
 pub mod cpu;
 pub mod device_manager;
+pub mod interrupt;
 pub mod memory_manager;
 pub mod vm;