OvmfPkg/Library/XenHypercallLib/X86XenHypercall.c

   1 /** @file
   2   Xen Hypercall Library implementation for Intel architecture
   3
   4 Copyright (c) 2014, Linaro Ltd. All rights reserved.<BR>
   5 This program and the accompanying materials are licensed and made available under
   6 the terms and conditions of the BSD License that accompanies this distribution.
   7 The full text of the license may be found at
   8 http://opensource.org/licenses/bsd-license.php.
   9
  10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include <PiDxe.h>
  16 #include <Library/HobLib.h>
  17 #include <Library/DebugLib.h>
  18 #include <Guid/XenInfo.h>
  19
  20 STATIC VOID    *HyperPage;
  21
  22 //
  23 // Interface exposed by the ASM implementation of the core hypercall
  24 //
  25 INTN
  26 EFIAPI
  27 __XenHypercall2 (
  28   IN     VOID *HypercallAddr,
  29   IN OUT INTN Arg1,
  30   IN OUT INTN Arg2
  31   );
  32
  33 /**
  34   Library constructor: retrieves the Hyperpage address
  35   from the gEfiXenInfoGuid HOB
  36 **/
  37
  38 RETURN_STATUS
  39 EFIAPI
  40 XenHypercallLibInit (
  41   VOID
  42   )
  43 {
  44   EFI_HOB_GUID_TYPE   *GuidHob;
  45   EFI_XEN_INFO        *XenInfo;
  46
  47   GuidHob = GetFirstGuidHob (&gEfiXenInfoGuid);
  48   if (GuidHob == NULL) {
  49     return RETURN_NOT_FOUND;
  50   }
  51   XenInfo = (EFI_XEN_INFO *) GET_GUID_HOB_DATA (GuidHob);
  52   HyperPage = XenInfo->HyperPages;
  53   return RETURN_SUCCESS;
  54 }
  55
  56 /**
  57   This function will put the two arguments in the right place (registers) and
  58   invoke the hypercall identified by HypercallID.
  59
  60   @param HypercallID    The symbolic ID of the hypercall to be invoked
  61   @param Arg1           First argument.
  62   @param Arg2           Second argument.
  63
  64   @return   Return 0 if success otherwise it return an errno.
  65 **/
  66 INTN
  67 EFIAPI
  68 XenHypercall2 (
  69   IN     UINTN  HypercallID,
  70   IN OUT INTN   Arg1,
  71   IN OUT INTN   Arg2
  72   )
  73 {
  74   ASSERT (HyperPage != NULL);
  75
  76   return __XenHypercall2 ((UINT8*)HyperPage + HypercallID * 32, Arg1, Arg2);
  77 }