Windows: Add Hyper-V isolation fields

Signed-off-by: John Howard <jhoward@microsoft.com>

Author: John Howard

config-windows.md

@@ -94,3 +94,23 @@ The following parameters can be specified:
         }
    }
 ```
+
+## <a name="configWindowsHyperV" />HyperV
+
+`hyperv` is an OPTIONAL field of the Windows configuration. If present, the container will be run with Hyper-V isolation. If omitted, the container will be run as a Windows Server container.
+
+The following parameters can be specified:
+
+* **`utilityvmpath`** *(string, OPTIONAL)* - specifies the path to the image used for the utility VM. If not supplied, the runtime will search the container filesystem layers from the bottom-most layer upwards, until it locates "UtilityVM", and default to that path.
+
+* **`sandboxpath`** *(string)* - specifies the root of the path to the sandbox to be used for the container.
+
+### Example
+
+```json
+    "windows": {
+        "hyperv": {
+            "sandboxpath": "C:\\\\programdata\\\\docker\\\\windowsfilter"
+        }
+    }
+```

specs-go/config.go

@@ -432,6 +432,16 @@ type SolarisAnet struct {
 type Windows struct {
 	// Resources contains information for handling resource constraints for the container.
 	Resources *WindowsResources `json:"resources,omitempty"`
+	// HyperV contains information for running a container with Hyper-V isolation.
+	HyperV *WindowsHyperV `json:"hyperv,omitempty"`
+}
+
+// WindowsHyperV contains information for configuring a container to run with Hyper-V isolation.
+type WindowsHyperV struct {
+	// UtilityVMPath is an optional path to the image used for the Utility VM.
+	UtilityVMPath string `json:"utilityvmpath,omitempty"`
+	// SandboxPath is a required host-path to the sandbox to be used by the container.
+	SandboxPath string `json:"sandboxpath"`
 }
 
 // WindowsResources has container runtime resource constraints for containers running on Windows.