vmm: interrupt: generify impl InterruptManager for MsiInterruptManager

The logic can be shared among hypervisor implementations.

The 'static bound is used such that we don't need to deal with extra
lifetime parameter everywhere. It should be okay because we know the
entry type E doesn't contain any reference.

Signed-off-by: Wei Liu <liuwe@microsoft.com>

vmm/src/interrupt.rs

@@ -103,24 +103,24 @@ impl InterruptRoute {
     }
 }
 
-struct RoutingEntry<E> {
+pub struct RoutingEntry<E> {
     route: E,
     masked: bool,
 }
 
 type KvmRoutingEntry = RoutingEntry<kvm_irq_routing_entry>;
 
-struct MsiInterruptGroup<E> {
+pub struct MsiInterruptGroup<E> {
     vm_fd: Arc<dyn hypervisor::Vm>,
     gsi_msi_routes: Arc<Mutex<HashMap<u32, RoutingEntry<E>>>>,
     irq_routes: HashMap<InterruptIndex, InterruptRoute>,
 }
 
-trait MsiInterruptGroupOps {
+pub trait MsiInterruptGroupOps {
     fn set_gsi_routes(&self) -> Result<()>;
 }
 
-trait RoutingEntryExt {
+pub trait RoutingEntryExt {
     fn make_entry(gsi: u32, config: &InterruptSourceConfig) -> Result<Box<Self>>;
 }
 
@@ -387,7 +387,12 @@ impl InterruptManager for LegacyUserspaceInterruptManager {
     }
 }
 
-impl InterruptManager for KvmMsiInterruptManager {
+impl<E> InterruptManager for MsiInterruptManager<E>
+where
+    E: Send + Sync + 'static,
+    RoutingEntry<E>: RoutingEntryExt,
+    MsiInterruptGroup<E>: MsiInterruptGroupOps,
+{
     type GroupConfig = MsiIrqGroupConfig;
 
     fn create_group(
@@ -401,7 +406,7 @@ impl InterruptManager for KvmMsiInterruptManager {
             irq_routes.insert(i, InterruptRoute::new(&mut allocator)?);
         }
 
-        Ok(Arc::new(Box::new(KvmMsiInterruptGroup::new(
+        Ok(Arc::new(Box::new(MsiInterruptGroup::new(
             self.vm_fd.clone(),
             self.gsi_msi_routes.clone(),
             irq_routes,