OvmfPkg/XenBusDxe: Add support to make Xen Hypercalls.

Change in V4:
- Replace the license by the commonly used file header text.
- add file header to XenHypercall.h (license, copyright, brief desc)

Change in V3:
- adding IA32 support. (not reviewed yet)
  both XenBusDxe/Ia32/hypercall.{S,asm} file are new

Change in V2:
- file header, copyright
- Add License
- Add push/pop instruction.
- fix types
- Comment of exported functions
- Improve coding style
- Add error handling in the main init function (of the drivers)
- Comment assembly

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16260 6f19259b-4bc3-4df7-8a09-765794883524

OvmfPkg/XenBusDxe/XenHypercall.h

@@ -0,0 +1,115 @@
+/** @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 __XENBUS_DXE_HYPERCALL_H__
+#define __XENBUS_DXE_HYPERCALL_H__
+
+typedef struct _XENBUS_DEVICE XENBUS_DEVICE;
+
+/**
+  This function will put the two arguments in the right place (registers) and
+  call HypercallAddr, which correspond to an entry in the hypercall pages.
+
+  @param HypercallAddr  A memory address where the hypercall to call is.
+  @param Arg1           First argument.
+  @param Arg2           Second argument.
+
+  @return   Return 0 if success otherwise it return an errno.
+**/
+INTN
+EFIAPI
+XenHypercall2 (
+  IN     VOID *HypercallAddr,
+  IN OUT INTN Arg1,
+  IN OUT INTN Arg2
+  );
+
+/**
+  Get the page where all hypercall are from the XenInfo hob.
+
+  @param Dev    A XENBUS_DEVICE instance.
+
+  @retval EFI_NOT_FOUND   hyperpage could not be found.
+  @retval EFI_SUCCESS     Successfully retrieve the hyperpage pointer.
+**/
+EFI_STATUS
+XenHyperpageInit (
+  XENBUS_DEVICE *Dev
+  );
+
+/**
+  Return the value of the HVM parameter Index.
+
+  @param Dev    A XENBUS_DEVICE instance.
+  @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 (
+  XENBUS_DEVICE *Dev,
+  INTN Index
+  );
+
+/**
+  Hypercall to do different operation on the memory.
+
+  @param Dev        A XENBUS_DEVICE instance.
+  @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     XENBUS_DEVICE *Dev,
+  IN     UINTN Operation,
+  IN OUT VOID *Arguments
+  );
+
+/**
+  Do an operation on the event channels.
+
+  @param Dev        A XENBUS_DEVICE instance.
+  @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     XENBUS_DEVICE *Dev,
+  IN     INTN Operation,
+  IN OUT VOID *Arguments
+  );
+
+/**
+  Map the shared_info_t page into memory.
+
+  @param Dev    A XENBUS_DEVICE instance.
+
+  @retval EFI_SUCCESS     Dev->SharedInfo whill contain a pointer to
+                          the shared info page
+  @retval EFI_LOAD_ERROR  The shared info page could not be mapped. The
+                          hypercall returned an error.
+**/
+EFI_STATUS
+XenGetSharedInfoPage (
+  IN OUT XENBUS_DEVICE *Dev
+  );
+
+#endif