devices: Refactor IOAPIC to cover other architectures

IOAPIC, a X86 specific interrupt controller, is referenced by device
manager and CPU manager. To work with more architectures, a common
type for all architectures is needed.
This commit introduces trait InterruptController to provide architecture
agnostic functions. Device manager and CPU manager can use it without
caring what the underlying device is.

Signed-off-by: Michael Zhao <michael.zhao@arm.com>

vmm/src/device_manager.rs

@@ -26,7 +26,10 @@ use anyhow::anyhow;
 use arch::layout;
 #[cfg(target_arch = "x86_64")]
 use arch::layout::{APIC_START, IOAPIC_SIZE, IOAPIC_START};
-use devices::{ioapic, BusDevice, HotPlugNotificationFlags};
+use devices::{
+    interrupt_controller, interrupt_controller::InterruptController, ioapic, BusDevice,
+    HotPlugNotificationFlags,
+};
 use kvm_ioctls::*;
 use libc::TIOCGWINSZ;
 use libc::{MAP_NORESERVE, MAP_PRIVATE, MAP_SHARED, O_TMPFILE, PROT_READ, PROT_WRITE};
@@ -235,8 +238,8 @@ pub enum DeviceManagerError {
     /// Failed to update interrupt source group.
     UpdateInterruptGroup(io::Error),
 
-    /// Failed creating IOAPIC.
-    CreateIoapic(ioapic::Error),
+    /// Failed creating interrupt controller.
+    CreateInterruptController(interrupt_controller::Error),
 
     /// Failed creating a new MmapRegion instance.
     NewMmapRegion(vm_memory::mmap::MmapRegionError),
@@ -626,8 +629,8 @@ pub struct DeviceManager {
     // Console abstraction
     console: Arc<Console>,
 
-    // IOAPIC
-    ioapic: Option<Arc<Mutex<ioapic::Ioapic>>>,
+    // Interrupt controller
+    interrupt_controller: Option<Arc<Mutex<ioapic::Ioapic>>>,
 
     // Things to be added to the commandline (i.e. for virtio-mmio)
     cmdline_additions: Vec<String>,
@@ -746,7 +749,7 @@ impl DeviceManager {
         let device_manager = DeviceManager {
             address_manager: Arc::clone(&address_manager),
             console: Arc::new(Console::default()),
-            ioapic: None,
+            interrupt_controller: None,
             cmdline_additions: Vec::new(),
             #[cfg(feature = "acpi")]
             ged_notification_device: None,
@@ -804,13 +807,15 @@ impl DeviceManager {
     pub fn create_devices(&mut self) -> DeviceManagerResult<()> {
         let mut virtio_devices: Vec<(VirtioDeviceArc, bool, String)> = Vec::new();
 
-        let ioapic = self.add_ioapic()?;
+        let interrupt_controller = self.add_interrupt_controller()?;
 
         // Now we can create the legacy interrupt manager, which needs the freshly
         // formed IOAPIC device.
         let legacy_interrupt_manager: Arc<
             dyn InterruptManager<GroupConfig = LegacyIrqGroupConfig>,
-        > = Arc::new(KvmLegacyUserspaceInterruptManager::new(ioapic));
+        > = Arc::new(KvmLegacyUserspaceInterruptManager::new(Arc::clone(
+            &interrupt_controller,
+        )));
 
         #[cfg(feature = "acpi")]
         self.address_manager
@@ -1003,33 +1008,37 @@ impl DeviceManager {
     }
 
     #[cfg(target_arch = "aarch64")]
-    fn add_ioapic(&mut self) -> DeviceManagerResult<Arc<Mutex<ioapic::Ioapic>>> {
+    fn add_interrupt_controller(
+        &mut self,
+    ) -> DeviceManagerResult<Arc<Mutex<dyn InterruptController>>> {
         unimplemented!();
     }
 
     #[cfg(target_arch = "x86_64")]
-    fn add_ioapic(&mut self) -> DeviceManagerResult<Arc<Mutex<ioapic::Ioapic>>> {
+    fn add_interrupt_controller(
+        &mut self,
+    ) -> DeviceManagerResult<Arc<Mutex<dyn InterruptController>>> {
         let id = String::from(IOAPIC_DEVICE_NAME);
 
         // Create IOAPIC
-        let ioapic = Arc::new(Mutex::new(
+        let interrupt_controller = Arc::new(Mutex::new(
             ioapic::Ioapic::new(
                 id.clone(),
                 APIC_START,
                 Arc::clone(&self.msi_interrupt_manager),
             )
-            .map_err(DeviceManagerError::CreateIoapic)?,
+            .map_err(DeviceManagerError::CreateInterruptController)?,
         ));
 
-        self.ioapic = Some(ioapic.clone());
+        self.interrupt_controller = Some(interrupt_controller.clone());
 
         self.address_manager
             .mmio_bus
-            .insert(ioapic.clone(), IOAPIC_START.0, IOAPIC_SIZE)
+            .insert(interrupt_controller.clone(), IOAPIC_START.0, IOAPIC_SIZE)
             .map_err(DeviceManagerError::BusError)?;
 
         self.bus_devices
-            .push(Arc::clone(&ioapic) as Arc<Mutex<dyn BusDevice>>);
+            .push(Arc::clone(&interrupt_controller) as Arc<Mutex<dyn BusDevice>>);
 
         // Fill the device tree with a new node. In case of restore, we
         // know there is nothing to do, so we can simply override the
@@ -1037,9 +1046,9 @@ impl DeviceManager {
         self.device_tree
             .lock()
             .unwrap()
-            .insert(id.clone(), device_node!(id, ioapic));
+            .insert(id.clone(), device_node!(id, interrupt_controller));
 
-        Ok(ioapic)
+        Ok(interrupt_controller)
     }
 
     #[cfg(feature = "acpi")]
@@ -2550,8 +2559,12 @@ impl DeviceManager {
         &self.address_manager.allocator
     }
 
-    pub fn ioapic(&self) -> &Option<Arc<Mutex<ioapic::Ioapic>>> {
-        &self.ioapic
+    pub fn interrupt_controller(&self) -> Option<Arc<Mutex<dyn InterruptController>>> {
+        if let Some(interrupt_controller) = &self.interrupt_controller {
+            Some(interrupt_controller.clone() as Arc<Mutex<dyn InterruptController>>)
+        } else {
+            None
+        }
     }
 
     pub fn console(&self) -> &Arc<Console> {