vmm: Implement VM pause

In order to pause a VM, we signal all the vCPU threads to get them out
of vmx non-root. Once out, the vCPU thread will check for a an atomic
pause boolean. If it's set to true, then the thread will park until
being resumed.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

vmm/src/api/http.rs

@@ -58,6 +58,7 @@ lazy_static! {
         r.routes.insert(endpoint!("/vm.boot"), Box::new(VmActionHandler::new(VmAction::Boot)));
         r.routes.insert(endpoint!("/vm.delete"), Box::new(VmActionHandler::new(VmAction::Delete)));
         r.routes.insert(endpoint!("/vm.info"), Box::new(VmInfo {}));
+        r.routes.insert(endpoint!("/vm.pause"), Box::new(VmActionHandler::new(VmAction::Pause)));
         r.routes.insert(endpoint!("/vm.shutdown"), Box::new(VmActionHandler::new(VmAction::Shutdown)));
         r.routes.insert(endpoint!("/vm.reboot"), Box::new(VmActionHandler::new(VmAction::Reboot)));
         r.routes.insert(endpoint!("/vmm.shutdown"), Box::new(VmmShutdown {}));

vmm/src/api/http_endpoint.rs

@@ -5,8 +5,8 @@
 
 use crate::api::http::EndpointHandler;
 use crate::api::{
-    vm_boot, vm_create, vm_delete, vm_info, vm_reboot, vm_shutdown, vmm_shutdown, ApiError,
-    ApiRequest, ApiResult, VmAction, VmConfig,
+    vm_boot, vm_create, vm_delete, vm_info, vm_pause, vm_reboot, vm_shutdown, vmm_shutdown,
+    ApiError, ApiRequest, ApiResult, VmAction, VmConfig,
 };
 use micro_http::{Body, Method, Request, Response, StatusCode, Version};
 use serde_json::Error as SerdeError;
@@ -29,6 +29,9 @@ pub enum HttpError {
     /// Could not get the VM information
     VmInfo(ApiError),
 
+    /// Could not pause the VM
+    VmPause(ApiError),
+
     /// Could not shut a VM down
     VmShutdown(ApiError),
 
@@ -103,6 +106,7 @@ impl VmActionHandler {
             VmAction::Delete => vm_delete,
             VmAction::Shutdown => vm_shutdown,
             VmAction::Reboot => vm_reboot,
+            VmAction::Pause => vm_pause,
         });
 
         VmActionHandler { action_fn }
@@ -122,6 +126,7 @@ impl EndpointHandler for VmActionHandler {
                     ApiError::VmBoot(_) => HttpError::VmBoot(e),
                     ApiError::VmShutdown(_) => HttpError::VmShutdown(e),
                     ApiError::VmReboot(_) => HttpError::VmReboot(e),
+                    ApiError::VmPause(_) => HttpError::VmPause(e),
                     _ => HttpError::VmAction(e),
                 }) {
                     Ok(_) => Response::new(Version::Http11, StatusCode::OK),

vmm/src/api/mod.rs

@@ -76,6 +76,9 @@ pub enum ApiError {
     /// The VM config is missing.
     VmMissingConfig,
 
+    /// The VM could not be paused.
+    VmPause(VmError),
+
     /// The VM is not booted.
     VmNotBooted,
 
@@ -132,6 +135,9 @@ pub enum ApiRequest {
     /// Request the VM information.
     VmInfo(Sender<ApiResponse>),
 
+    /// Pause a VM.
+    VmPause(Sender<ApiResponse>),
+
     /// Shut the previously booted virtual machine down.
     /// If the VM was not previously booted or created, the VMM API server
     /// will send a VmShutdown error back.
@@ -181,6 +187,9 @@ pub enum VmAction {
 
     /// Reboot a VM
     Reboot,
+
+    /// Pause a VM
+    Pause,
 }
 
 fn vm_action(api_evt: EventFd, api_sender: Sender<ApiRequest>, action: VmAction) -> ApiResult<()> {
@@ -191,6 +200,7 @@ fn vm_action(api_evt: EventFd, api_sender: Sender<ApiRequest>, action: VmAction)
         VmAction::Delete => ApiRequest::VmDelete(response_sender),
         VmAction::Shutdown => ApiRequest::VmShutdown(response_sender),
         VmAction::Reboot => ApiRequest::VmReboot(response_sender),
+        VmAction::Pause => ApiRequest::VmPause(response_sender),
     };
 
     // Send the VM request.
@@ -218,6 +228,10 @@ pub fn vm_reboot(api_evt: EventFd, api_sender: Sender<ApiRequest>) -> ApiResult<
     vm_action(api_evt, api_sender, VmAction::Reboot)
 }
 
+pub fn vm_pause(api_evt: EventFd, api_sender: Sender<ApiRequest>) -> ApiResult<()> {
+    vm_action(api_evt, api_sender, VmAction::Pause)
+}
+
 pub fn vm_info(api_evt: EventFd, api_sender: Sender<ApiRequest>) -> ApiResult<VmInfo> {
     let (response_sender, response_receiver) = channel();
 

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

@@ -80,6 +80,21 @@ paths:
           description: The VM instance could not boot because it is not created yet
           content: {}
 
+  /vm.pause:
+    put:
+      summary: Pause a previously booted VM instance.
+      operationId: pauseVM
+      responses:
+        201:
+          description: The VM instance successfully paused.
+          content: {}
+        404:
+          description: The VM instance could not pause because it is not created yet
+          content: {}
+        405:
+          description: The VM instance could not pause because it is not booted.
+          content: {}
+
   /vm.shutdown:
     put:
       summary: Shut the VM instance down.