vmm: Simplify the way memory is snapshot and restored

By using a single file for storing the memory ranges, we simplify the
way snapshot/restore works by avoiding multiples files, but the main and
more important point is that we have now a way to save only the ranges
that matter. In particular, the ranges related to virtio-mem regions are
not always fully hotplugged, meaning we don't want to save the entire
region. That's where the usage of memory ranges is interesting as it
lets us optimize the snapshot/restore process when one or multiple
virtio-mem regions are involved.

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

vmm/src/vm.rs

@@ -2188,7 +2188,10 @@ impl Vm {
     }
 
     pub fn memory_range_table(&self) -> std::result::Result<MemoryRangeTable, MigratableError> {
-        self.memory_manager.lock().unwrap().memory_range_table()
+        self.memory_manager
+            .lock()
+            .unwrap()
+            .memory_range_table(false)
     }
 
     pub fn device_tree(&self) -> Arc<Mutex<DeviceTree>> {