vmm: Remove all Weak references from DeviceManager

Now that the BusDevice devices are stored as Weak references by the
IO and MMIO buses, there's no need to use Weak references from the
DeviceManager anymore.

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

vmm/src/cpu.rs

@@ -507,7 +507,7 @@ impl CpuManager {
         let cpu_manager = Arc::new(Mutex::new(CpuManager {
             boot_vcpus,
             max_vcpus,
-            io_bus: device_manager.io_bus(),
+            io_bus: device_manager.io_bus().clone(),
             mmio_bus: device_manager.mmio_bus().clone(),
             ioapic: device_manager.ioapic().clone(),
             vm_memory: guest_memory,

vmm/src/device_manager.rs

@@ -39,7 +39,6 @@ use std::io::{self, sink, stdout};
 use std::os::unix::fs::OpenOptionsExt;
 use std::path::PathBuf;
 use std::result;
-use std::sync::Weak;
 use std::sync::{Arc, Mutex};
 use tempfile::NamedTempFile;
 #[cfg(feature = "pci_support")]
@@ -277,7 +276,7 @@ impl Console {
 
 struct AddressManager {
     allocator: Arc<Mutex<SystemAllocator>>,
-    io_bus: Weak<devices::Bus>,
+    io_bus: Arc<devices::Bus>,
     mmio_bus: Arc<devices::Bus>,
     vm_fd: Arc<VmFd>,
 }
@@ -310,8 +309,6 @@ impl DeviceRelocation for AddressManager {
 
                 // Update PIO bus
                 self.io_bus
-                    .upgrade()
-                    .unwrap()
                     .update_range(old_base, len, new_base, len)
                     .map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
             }
@@ -489,7 +486,7 @@ impl DeviceManager {
 
         let address_manager = Arc::new(AddressManager {
             allocator,
-            io_bus: Arc::downgrade(io_bus),
+            io_bus: Arc::clone(io_bus),
             mmio_bus: Arc::new(devices::Bus::new()),
             vm_fd: vm_fd.clone(),
         });
@@ -535,8 +532,6 @@ impl DeviceManager {
         #[cfg(feature = "acpi")]
         address_manager
             .io_bus
-            .upgrade()
-            .unwrap()
             .insert(memory_manager.clone(), 0xa00, 0x18)
             .map_err(DeviceManagerError::BusError)?;
 
@@ -608,8 +603,6 @@ impl DeviceManager {
         #[cfg(feature = "acpi")]
         address_manager
             .io_bus
-            .upgrade()
-            .unwrap()
             .insert(
                 Arc::clone(&device_manager) as Arc<Mutex<dyn BusDevice>>,
                 0xae00,
@@ -685,8 +678,6 @@ impl DeviceManager {
                 .push(Arc::clone(&pci_config_io) as Arc<Mutex<dyn BusDevice>>);
             self.address_manager
                 .io_bus
-                .upgrade()
-                .unwrap()
                 .insert(pci_config_io, 0xcf8, 0x8)
                 .map_err(DeviceManagerError::BusError)?;
             let pci_config_mmio = Arc::new(Mutex::new(PciConfigMmio::new(Arc::clone(&pci_bus))));
@@ -774,8 +765,6 @@ impl DeviceManager {
 
         self.address_manager
             .io_bus
-            .upgrade()
-            .unwrap()
             .insert(acpi_device, 0x3c0, 0x4)
             .map_err(DeviceManagerError::BusError)?;
 
@@ -810,8 +799,6 @@ impl DeviceManager {
 
         self.address_manager
             .io_bus
-            .upgrade()
-            .unwrap()
             .insert(ged_device.clone(), 0xb000, 0x1)
             .map_err(DeviceManagerError::BusError)?;
         Ok(Some(ged_device))
@@ -826,8 +813,6 @@ impl DeviceManager {
 
         self.address_manager
             .io_bus
-            .upgrade()
-            .unwrap()
             .insert(i8042, 0x61, 0x4)
             .map_err(DeviceManagerError::BusError)?;
         #[cfg(feature = "cmos")]
@@ -856,8 +841,6 @@ impl DeviceManager {
 
             self.address_manager
                 .io_bus
-                .upgrade()
-                .unwrap()
                 .insert(cmos, 0x70, 0x2)
                 .map_err(DeviceManagerError::BusError)?;
         }
@@ -906,8 +889,6 @@ impl DeviceManager {
 
             self.address_manager
                 .io_bus
-                .upgrade()
-                .unwrap()
                 .insert(serial.clone(), 0x3f8, 0x8)
                 .map_err(DeviceManagerError::BusError)?;
 
@@ -1476,7 +1457,7 @@ impl DeviceManager {
 
         pci.register_mapping(
             vfio_pci_device,
-            self.address_manager.io_bus.upgrade().unwrap().as_ref(),
+            self.address_manager.io_bus.as_ref(),
             self.address_manager.mmio_bus.as_ref(),
             bars,
         )
@@ -1585,7 +1566,7 @@ impl DeviceManager {
 
         pci.register_mapping(
             virtio_pci_device.clone(),
-            self.address_manager.io_bus.upgrade().unwrap().as_ref(),
+            self.address_manager.io_bus.as_ref(),
             self.address_manager.mmio_bus.as_ref(),
             bars,
         )
@@ -1659,8 +1640,8 @@ impl DeviceManager {
         Ok(())
     }
 
-    pub fn io_bus(&self) -> Arc<devices::Bus> {
+    pub fn io_bus(&self) -> &Arc<devices::Bus> {
-        Arc::clone(&self.address_manager.io_bus.upgrade().unwrap())
+        &self.address_manager.io_bus
     }
 
     pub fn mmio_bus(&self) -> &Arc<devices::Bus> {