virtio-balloon: Add memory_actual_size to vm.info to show memory actual size

The virtio-balloon change the memory size is asynchronous.
VirtioBalloonConfig.actual of balloon device show current balloon size.

This commit add memory_actual_size to vm.info to show memory actual size.

Signed-off-by: Hui Zhu <teawater@antfin.com>

vmm/src/api/mod.rs

@@ -145,6 +145,7 @@ pub type ApiResult<T> = std::result::Result<T, ApiError>;
 pub struct VmInfo {
     pub config: Arc<Mutex<VmConfig>>,
     pub state: VmState,
+    pub memory_actual_size: u64,
 }
 
 #[derive(Clone, Deserialize, Serialize)]

vmm/src/api/openapi/cloud-hypervisor.yaml

@@ -360,6 +360,9 @@ components:
         state:
           type: string
           enum: [Created, Running, Shutdown, Paused]
+        memory_actual_size:
+          type: integer
+          format: int64
       description: Virtual Machine information
 
     VmCounters:

vmm/src/config.rs

@@ -534,6 +534,24 @@ impl MemoryConfig {
             zones,
         })
     }
+
+    pub fn total_size(&self) -> u64 {
+        let mut size = self.size;
+        if let Some(hotplugged_size) = self.hotplugged_size {
+            size += hotplugged_size;
+        }
+
+        if let Some(zones) = &self.zones {
+            for zone in zones.iter() {
+                size += zone.size;
+                if let Some(hotplugged_size) = zone.hotplugged_size {
+                    size += hotplugged_size;
+                }
+            }
+        }
+
+        size
+    }
 }
 
 impl Default for MemoryConfig {

vmm/src/lib.rs

@@ -465,9 +465,17 @@ impl Vmm {
                     None => VmState::Created,
                 };
 
+                let config = Arc::clone(config);
+
+                let mut memory_actual_size = config.lock().unwrap().memory.total_size();
+                if let Some(vm) = &self.vm {
+                    memory_actual_size -= vm.get_balloon_actual();
+                }
+
                 Ok(VmInfo {
-                    config: Arc::clone(config),
+                    config,
                     state,
+                    memory_actual_size,
                 })
             }
             None => Err(VmError::VmNotCreated),

vmm/src/memory_manager.rs

@@ -1236,6 +1236,14 @@ impl MemoryManager {
         Ok(balloon_size)
     }
 
+    pub fn get_balloon_actual(&self) -> u64 {
+        if let Some(balloon) = &self.balloon {
+            return balloon.lock().unwrap().get_actual();
+        }
+
+        0
+    }
+
     /// In case this function resulted in adding a new memory region to the
     /// guest memory, the new region is returned to the caller. The virtio-mem
     /// use case never adds a new region as the whole hotpluggable memory has

vmm/src/vm.rs

@@ -1493,6 +1493,11 @@ impl Vm {
 
         Ok(())
     }
+
+    /// Gets the actual size of the balloon.
+    pub fn get_balloon_actual(&self) -> u64 {
+        self.memory_manager.lock().unwrap().get_balloon_actual()
+    }
 }
 
 impl Pausable for Vm {