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/Library/XenHypercallLib/XenHypercall.c

@@ -0,0 +1,63 @@
+/** @file
+  Functions 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.
+
+**/
+
+#include <PiDxe.h>
+
+#include <IndustryStandard/Xen/hvm/params.h>
+#include <IndustryStandard/Xen/memory.h>
+
+#include <Library/DebugLib.h>
+#include <Library/XenHypercallLib.h>
+
+UINT64
+XenHypercallHvmGetParam (
+  IN UINT32        Index
+  )
+{
+  xen_hvm_param_t     Parameter;
+  INTN                Error;
+
+  Parameter.domid = DOMID_SELF;
+  Parameter.index = Index;
+  Error = XenHypercall2 (__HYPERVISOR_hvm_op,
+                         HVMOP_get_param, (INTN) &Parameter);
+  if (Error != 0) {
+    DEBUG ((EFI_D_ERROR,
+            "XenHypercall: Error %d trying to get HVM parameter %d\n",
+            Error, Index));
+    return 0;
+  }
+  return Parameter.value;
+}
+
+INTN
+XenHypercallMemoryOp (
+  IN     UINTN Operation,
+  IN OUT VOID *Arguments
+  )
+{
+  return XenHypercall2 (__HYPERVISOR_memory_op,
+                        Operation, (INTN) Arguments);
+}
+
+INTN
+XenHypercallEventChannelOp (
+  IN     INTN Operation,
+  IN OUT VOID *Arguments
+  )
+{
+  return XenHypercall2 (__HYPERVISOR_event_channel_op,
+                        Operation, (INTN) Arguments);
+}