ArmVirtualizationPkg: add XenIoMmioLib

This adds a XenIoMmioLib declaration and implementation that can
be invoked to install the XENIO_PROTOCOL and a corresponding
grant table address on a EFI handle.

Contributed-under: TianoCore Contribution Agreement 1.0
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16979 6f19259b-4bc3-4df7-8a09-765794883524

OvmfPkg/Include/Library/XenIoMmioLib.h

@@ -0,0 +1,64 @@
+/** @file
+*  Manage XenBus device path and I/O handles
+*
+*  Copyright (c) 2015, Linaro Ltd. All rights reserved.<BR>
+*
+*  This program and the accompanying materials are
+*  licensed and made available under the terms and conditions of the BSD License
+*  which accompanies this distribution.  The full text of the license may be found at
+*  http://opensource.org/licenses/bsd-license.php
+*
+*  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+*  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+*
+**/
+
+#ifndef _XENIO_MMIO_DEVICE_LIB_H_
+#define _XENIO_MMIO_DEVICE_LIB_H_
+
+/**
+
+  Install the XENBUS_ROOT_DEVICE_PATH and XENIO_PROTOCOL protocols on
+  the handle pointed to by @Handle, or on a new handle if it points to
+  NULL
+
+  @param  Handle                Pointer to the handle to install the protocols
+                                on, may point to a NULL handle.
+
+  @param  GrantTableAddress     The address of the Xen grant table
+
+  @retval EFI_SUCCESS           Protocols were installed successfully
+
+  @retval EFI_OUT_OF_RESOURCES  The function failed to allocate memory required
+                                by the XenIo MMIO and device path protocols
+
+  @return                       Status code returned by the boot service
+                                InstallMultipleProtocolInterfaces ()
+
+**/
+EFI_STATUS
+XenIoMmioInstall (
+  IN OUT   EFI_HANDLE              *Handle,
+  IN       EFI_PHYSICAL_ADDRESS    GrantTableAddress
+  );
+
+
+/**
+
+  Uninstall the XENBUS_ROOT_DEVICE_PATH and XENIO_PROTOCOL protocols
+
+  @param  Handle          Handle onto which the protocols have been installed
+                          earlier by XenIoMmioInstall ()
+
+  @retval EFI_SUCCESS     Protocols were uninstalled successfully
+
+  @return                 Status code returned by the boot service
+                          UninstallMultipleProtocolInterfaces ()
+
+**/
+EFI_STATUS
+XenIoMmioUninstall (
+  IN       EFI_HANDLE              Handle
+  );
+
+#endif