vmm: openapi: Add the /vm.counters API entry point

This is a hash table of string to hash tables of u64s. In JSON these
hash tables are object types.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

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

@@ -42,6 +42,17 @@ paths:
               schema:
                 $ref: '#/components/schemas/VmInfo'
 
+  /vm.counters:
+    get:
+      summary: Get counters from the VM
+      responses:
+        200:
+          description: The VM counters
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/VmCounters'
+
   /vm.create:
     put:
       summary: Create the cloud-hypervisor Virtual Machine (VM) instance. The instance is not booted, only created.
@@ -335,6 +346,14 @@ components:
           enum: [Created, Running, Shutdown, Paused]
       description: Virtual Machine information
 
+    VmCounters:
+      type: object
+      additionalProperties:
+        type: object
+        additionalProperties:
+          type: integer
+          format: uint64
+
     PciDeviceInfo:
       required:
       - id