vmm: Group virtio-mem fields under a dedicated structure

This patch simplifies the code as we have one single Option for the
VirtioMemZone. This also prepares for storing additional information
related to the virtio-mem region.

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

vmm/src/device_manager.rs

@@ -2430,10 +2430,7 @@ impl DeviceManager {
         let mm = self.memory_manager.clone();
         let mm = mm.lock().unwrap();
         for (_memory_zone_id, memory_zone) in mm.memory_zones().iter() {
-            if let (Some(region), Some(resize)) = (
+            if let Some(virtio_mem_zone) = memory_zone.virtio_mem_zone() {
-                memory_zone.virtio_mem_region(),
-                memory_zone.virtio_mem_resize(),
-            ) {
                 let id = self.next_device_name(MEM_DEVICE_NAME_PREFIX)?;
 
                 #[cfg(not(feature = "acpi"))]
@@ -2445,8 +2442,9 @@ impl DeviceManager {
                 let virtio_mem_device = Arc::new(Mutex::new(
                     virtio_devices::Mem::new(
                         id.clone(),
-                        &region,
+                        virtio_mem_zone.region(),
-                        resize
+                        virtio_mem_zone
+                            .resize_handler()
                             .try_clone()
                             .map_err(DeviceManagerError::TryCloneVirtioMemResize)?,
                         self.seccomp_action.clone(),

vmm/src/memory_manager.rs

@@ -64,22 +64,32 @@ struct HotPlugState {
     removing: bool,
 }
 
+pub struct VirtioMemZone {
+    region: Arc<GuestRegionMmap>,
+    resize_handler: virtio_devices::Resize,
+}
+
+impl VirtioMemZone {
+    pub fn region(&self) -> &Arc<GuestRegionMmap> {
+        &self.region
+    }
+    pub fn resize_handler(&self) -> &virtio_devices::Resize {
+        &self.resize_handler
+    }
+}
+
 #[derive(Default)]
 pub struct MemoryZone {
     regions: Vec<Arc<GuestRegionMmap>>,
-    virtio_mem_region: Option<Arc<GuestRegionMmap>>,
+    virtio_mem_zone: Option<VirtioMemZone>,
-    virtio_mem_resize: Option<virtio_devices::Resize>,
 }
 
 impl MemoryZone {
     pub fn regions(&self) -> &Vec<Arc<GuestRegionMmap>> {
         &self.regions
     }
-    pub fn virtio_mem_region(&self) -> &Option<Arc<GuestRegionMmap>> {
+    pub fn virtio_mem_zone(&self) -> &Option<VirtioMemZone> {
-        &self.virtio_mem_region
+        &self.virtio_mem_zone
-    }
-    pub fn virtio_mem_resize(&self) -> &Option<virtio_devices::Resize> {
-        &self.virtio_mem_resize
     }
 }
 
@@ -598,9 +608,11 @@ impl MemoryManager {
 
                         virtio_mem_regions.push(region.clone());
 
-                        memory_zone.virtio_mem_region = Some(region);
+                        memory_zone.virtio_mem_zone = Some(VirtioMemZone {
-                        memory_zone.virtio_mem_resize =
+                            region,
-                            Some(virtio_devices::Resize::new().map_err(Error::EventFdFail)?);
+                            resize_handler: virtio_devices::Resize::new()
+                                .map_err(Error::EventFdFail)?,
+                        });
 
                         start_of_device_area = start_addr.unchecked_add(hotplug_size);
                     }
@@ -1186,8 +1198,11 @@ impl MemoryManager {
 
     pub fn virtio_mem_resize(&mut self, id: &str, size: u64) -> Result<(), Error> {
         if let Some(memory_zone) = self.memory_zones.get_mut(id) {
-            if let Some(resize) = &memory_zone.virtio_mem_resize {
+            if let Some(virtio_mem_zone) = memory_zone.virtio_mem_zone() {
-                resize.work(size).map_err(Error::VirtioMemResizeFail)?;
+                virtio_mem_zone
+                    .resize_handler()
+                    .work(size)
+                    .map_err(Error::VirtioMemResizeFail)?;
             } else {
                 error!("Failed resizing virtio-mem region: No virtio-mem handler");
                 return Err(Error::MissingVirtioMemHandler);