vmm: Create a MemoryZone structure

In order to anticipate the need for storing memory regions along with
virtio-mem information for each memory zone, we create a new structure
MemoryZone that will replace Vec<Arc<GuestRegionMmap>> in the hash map
MemoryZones.

This makes thing more logical as MemoryZones becomes a list of
MemoryZone sorted by their identifier.

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

vmm/src/vm.rs

@@ -404,7 +404,7 @@ impl Vm {
                 if let Some(memory_zones) = &config.memory_zones {
                     for memory_zone in memory_zones.iter() {
                         if let Some(mm_zone) = mm_zones.get(memory_zone) {
-                            node.memory_regions.extend(mm_zone.clone());
+                            node.memory_regions.extend(mm_zone.regions().clone());
                         } else {
                             error!("Unknown memory zone '{}'", memory_zone);
                             return Err(Error::InvalidNumaConfig);