refactor(acpi): Make ACPIDeviceManager fields private

Thanks to the last commit introducing immutable accessors, the internal
fields of ACPIDeviceManager no longer need to be public.

Make the fields private to prevent external code from mutating them.

Signed-off-by: Takahiro Itazuri <itazur@amazon.com>

Author: zulinx86

src/vmm/src/device_manager/acpi.rs

@@ -20,22 +20,22 @@ pub enum ACPIDeviceError {
     NotifyGuest(#[from] std::io::Error),
 }
 
-#[derive(Debug)]
+// Although both VMGenID and VMClock devices are always present, they should be instantiated when
+// they are attached to preserve the existing ordering of GSI allocation.
+#[derive(Debug, Default)]
 pub struct ACPIDeviceManager {
     /// VMGenID device
-    pub vmgenid: Option<VmGenId>,
+    vmgenid: Option<VmGenId>,
     /// VMclock device
-    pub vmclock: Option<VmClock>,
+    vmclock: Option<VmClock>,
 }
 
 impl ACPIDeviceManager {
     /// Create a new ACPIDeviceManager object
-    pub fn new() -> Self {
-        // Although both VMGenID and VMClock devices are always present, they should be instantiated
-        // when they are attached to preserve the existing ordering of GSI allocation.
+    pub fn new(vmgenid: VmGenId, vmclock: VmClock) -> Self {
         ACPIDeviceManager {
-            vmgenid: None,
-            vmclock: None,
+            vmgenid: Some(vmgenid),
+            vmclock: Some(vmclock),
         }
     }
 

src/vmm/src/device_manager/mod.rs

@@ -174,7 +174,7 @@ impl DeviceManager {
             mmio_devices: MMIODeviceManager::new(),
             #[cfg(target_arch = "x86_64")]
             legacy_devices,
-            acpi_devices: ACPIDeviceManager::new(),
+            acpi_devices: ACPIDeviceManager::default(),
             pci_devices: PciDevices::new(),
         })
     }
@@ -559,10 +559,10 @@ pub(crate) mod tests {
     pub(crate) fn default_device_manager() -> DeviceManager {
         let mut resource_allocator = ResourceAllocator::new();
         let mmio_devices = MMIODeviceManager::new();
-        let acpi_devices = ACPIDeviceManager {
-            vmgenid: Some(VmGenId::new(&mut resource_allocator)),
-            vmclock: Some(VmClock::new(&mut resource_allocator)),
-        };
+        let acpi_devices = ACPIDeviceManager::new(
+            VmGenId::new(&mut resource_allocator),
+            VmClock::new(&mut resource_allocator),
+        );
         let pci_devices = PciDevices::new();
 
         #[cfg(target_arch = "x86_64")]

src/vmm/src/device_manager/persist.rs

@@ -183,12 +183,12 @@ impl<'a> Persist<'a> for ACPIDeviceManager {
     }
 
     fn restore(vm: Self::ConstructorArgs, state: &Self::State) -> Result<Self, Self::Error> {
-        let mut acpi_devices = ACPIDeviceManager {
+        let mut acpi_devices = ACPIDeviceManager::new(
             // Safe to unwrap() here, this will never return an error.
-            vmgenid: Some(VmGenId::restore((), &state.vmgenid).unwrap()),
+            VmGenId::restore((), &state.vmgenid).unwrap(),
             // Safe to unwrap() here, this will never return an error.
-            vmclock: Some(VmClock::restore((), &state.vmclock).unwrap()),
-        };
+            VmClock::restore((), &state.vmclock).unwrap(),
+        );
 
         acpi_devices.activate_vmgenid(vm)?;
         acpi_devices.do_post_restore_vmgenid()?;