Ovmf/Xen: move XenBusDxe hypercall code to separate library

This moves all of the Xen hypercall code that was private to XenBusDxe
to a new library class XenHypercallLib. This will allow us to reimplement
it for ARM, and to export the Xen hypercall functionality to other parts
of the code, such as a Xen console SerialPortLib driver.

Contributed-under: TianoCore Contribution Agreement 1.0
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.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@16970 6f19259b-4bc3-4df7-8a09-765794883524

OvmfPkg/Include/Library/XenHypercallLib.h

@@ -0,0 +1,79 @@
+/** @file
+  Functions declarations to make Xen hypercalls.
+
+  Copyright (C) 2014, Citrix Ltd.
+
+  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 __XEN_HYPERCALL_LIB_H__
+#define __XEN_HYPERCALL_LIB_H__
+
+/**
+  This function will put the two arguments in the right place (registers) and
+  invoke the hypercall identified by HypercallID.
+
+  @param HypercallID    The symbolic ID of the hypercall to be invoked
+  @param Arg1           First argument.
+  @param Arg2           Second argument.
+
+  @return   Return 0 if success otherwise it return an errno.
+**/
+INTN
+EFIAPI
+XenHypercall2 (
+  IN     UINTN  HypercallID,
+  IN OUT INTN   Arg1,
+  IN OUT INTN   Arg2
+  );
+
+/**
+  Return the value of the HVM parameter Index.
+
+  @param Index  The parameter to get, e.g. HVM_PARAM_STORE_EVTCHN.
+
+  @return   The value of the asked parameter or 0 in case of error.
+**/
+UINT64
+XenHypercallHvmGetParam (
+  UINT32 Index
+  );
+
+/**
+  Hypercall to do different operation on the memory.
+
+  @param Operation  The operation number, e.g. XENMEM_add_to_physmap.
+  @param Arguments  The arguments associated to the operation.
+
+  @return  Return the return value from the hypercall, 0 in case of success
+           otherwise, an error code.
+**/
+INTN
+XenHypercallMemoryOp (
+  IN     UINTN Operation,
+  IN OUT VOID *Arguments
+  );
+
+/**
+  Do an operation on the event channels.
+
+  @param Operation  The operation number, e.g. EVTCHNOP_send.
+  @param Arguments  The argument associated to the operation.
+
+  @return  Return the return value from the hypercall, 0 in case of success
+           otherwise, an error code.
+**/
+INTN
+XenHypercallEventChannelOp (
+  IN     INTN Operation,
+  IN OUT VOID *Arguments
+  );
+
+#endif