vmm: Add a 'resize-zone' action to the API actions

Implement a new VM action called 'resize-zone' allowing the user to
resize one specific memory zone at a time. This relies on all the
preliminary work from the previous commits to resize each virtio-mem
device independently from each others.

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

vmm/src/api/http.rs

@@ -68,6 +68,9 @@ pub enum HttpError {
     /// Could not resize a VM
     VmResize(ApiError),
 
+    /// Could not resize a memory zone
+    VmResizeZone(ApiError),
+
     /// Could not add a device to a VM
     VmAddDevice(ApiError),
 
@@ -204,6 +207,7 @@ lazy_static! {
         r.routes.insert(endpoint!("/vm.reboot"), Box::new(VmActionHandler::new(VmAction::Reboot)));
         r.routes.insert(endpoint!("/vm.remove-device"), Box::new(VmActionHandler::new(VmAction::RemoveDevice(Arc::default()))));
         r.routes.insert(endpoint!("/vm.resize"), Box::new(VmActionHandler::new(VmAction::Resize(Arc::default()))));
+        r.routes.insert(endpoint!("/vm.resize-zone"), Box::new(VmActionHandler::new(VmAction::ResizeZone(Arc::default()))));
         r.routes.insert(endpoint!("/vm.restore"), Box::new(VmActionHandler::new(VmAction::Restore(Arc::default()))));
         r.routes.insert(endpoint!("/vm.resume"), Box::new(VmActionHandler::new(VmAction::Resume)));
         r.routes.insert(endpoint!("/vm.shutdown"), Box::new(VmActionHandler::new(VmAction::Shutdown)));

vmm/src/api/http_endpoint.rs

@@ -7,8 +7,8 @@ use crate::api::http::{error_response, EndpointHandler, HttpError};
 use crate::api::{
     vm_add_device, vm_add_disk, vm_add_fs, vm_add_net, vm_add_pmem, vm_add_vsock, vm_boot,
     vm_counters, vm_create, vm_delete, vm_info, vm_pause, vm_reboot, vm_remove_device, vm_resize,
-    vm_restore, vm_resume, vm_shutdown, vm_snapshot, vmm_ping, vmm_shutdown, ApiRequest, VmAction,
-    VmConfig,
+    vm_resize_zone, vm_restore, vm_resume, vm_shutdown, vm_snapshot, vmm_ping, vmm_shutdown,
+    ApiRequest, VmAction, VmConfig,
 };
 use micro_http::{Body, Method, Request, Response, StatusCode, Version};
 use std::sync::mpsc::Sender;
@@ -132,6 +132,13 @@ impl EndpointHandler for VmActionHandler {
                 )
                 .map_err(HttpError::VmResize),
 
+                ResizeZone(_) => vm_resize_zone(
+                    api_notifier,
+                    api_sender,
+                    Arc::new(serde_json::from_slice(body.raw())?),
+                )
+                .map_err(HttpError::VmResizeZone),
+
                 Restore(_) => vm_restore(
                     api_notifier,
                     api_sender,

vmm/src/api/mod.rs

@@ -109,6 +109,9 @@ pub enum ApiError {
     /// The VM could not be resized
     VmResize(VmError),
 
+    /// The memory zone could not be resized.
+    VmResizeZone(VmError),
+
     /// The device could not be added to the VM.
     VmAddDevice(VmError),
 
@@ -156,6 +159,12 @@ pub struct VmResizeData {
     pub desired_ram_w_balloon: Option<u64>,
 }
 
+#[derive(Clone, Deserialize, Serialize, Default)]
+pub struct VmResizeZoneData {
+    pub id: String,
+    pub desired_ram: u64,
+}
+
 #[derive(Clone, Deserialize, Serialize, Default)]
 pub struct VmRemoveDeviceData {
     pub id: String,
@@ -236,6 +245,9 @@ pub enum ApiRequest {
     /// Resize the VM.
     VmResize(Arc<VmResizeData>, Sender<ApiResponse>),
 
+    /// Resize the memory zone.
+    VmResizeZone(Arc<VmResizeZoneData>, Sender<ApiResponse>),
+
     /// Add a device to the VM.
     VmAddDevice(Arc<DeviceConfig>, Sender<ApiResponse>),
 
@@ -331,6 +343,9 @@ pub enum VmAction {
     /// Resize VM
     Resize(Arc<VmResizeData>),
 
+    /// Resize memory zone
+    ResizeZone(Arc<VmResizeZoneData>),
+
     /// Restore VM
     Restore(Arc<RestoreConfig>),
 
@@ -362,6 +377,7 @@ fn vm_action(
         AddVsock(v) => ApiRequest::VmAddVsock(v, response_sender),
         RemoveDevice(v) => ApiRequest::VmRemoveDevice(v, response_sender),
         Resize(v) => ApiRequest::VmResize(v, response_sender),
+        ResizeZone(v) => ApiRequest::VmResizeZone(v, response_sender),
         Restore(v) => ApiRequest::VmRestore(v, response_sender),
         Snapshot(v) => ApiRequest::VmSnapshot(v, response_sender),
     };
@@ -478,6 +494,14 @@ pub fn vm_resize(
     vm_action(api_evt, api_sender, VmAction::Resize(data))
 }
 
+pub fn vm_resize_zone(
+    api_evt: EventFd,
+    api_sender: Sender<ApiRequest>,
+    data: Arc<VmResizeZoneData>,
+) -> ApiResult<Option<Body>> {
+    vm_action(api_evt, api_sender, VmAction::ResizeZone(data))
+}
+
 pub fn vm_add_device(
     api_evt: EventFd,
     api_sender: Sender<ApiRequest>,

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

@@ -150,6 +150,22 @@ paths:
         404:
           description: The VM instance could not be resized because it is not created.
 
+  /vm.resize-zone:
+    put:
+      summary: Resize a memory zone
+      requestBody:
+        description: The target size for the memory zone
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/VmResizeZone'
+        required: true
+      responses:
+        204:
+          description: The memory zone was successfully resized.
+        500:
+          description: The memory zone could not be resized.
+
   /vm.add-device:
     put:
       summary: Add a new device to the VM
@@ -774,6 +790,16 @@ components:
           type: integer
           format: int64
 
+    VmResizeZone:
+      type: object
+      properties:
+        id:
+          type: string
+        desired_ram:
+          description: desired memory zone size in bytes
+          type: integer
+          format: int64
+
     VmAddDevice:
       type: object
       properties: