From 2dbb37617531501329975fa69a71918418a10c21 Mon Sep 17 00:00:00 2001
From: Sebastien Boeuf <sebastien.boeuf@intel.com>
Date: Wed, 4 Mar 2020 16:24:15 +0100
Subject: [PATCH] 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            |  2 +-
 vmm/src/device_manager.rs | 31 ++++++-------------------------
 2 files changed, 7 insertions(+), 26 deletions(-)

diff --git a/vmm/src/cpu.rs b/vmm/src/cpu.rs
index ba0c46258..04e6bc222 100644
--- a/vmm/src/cpu.rs
+++ b/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,
diff --git a/vmm/src/device_manager.rs b/vmm/src/device_manager.rs
index 722d0a3db..d8f1c84a1 100644
--- a/vmm/src/device_manager.rs
+++ b/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> {
-        Arc::clone(&self.address_manager.io_bus.upgrade().unwrap())
+    pub fn io_bus(&self) -> &Arc<devices::Bus> {
+        &self.address_manager.io_bus
     }
 
     pub fn mmio_bus(&self) -> &Arc<devices::Bus> {