OvmfPkg/IoMmuDxe/IoMmuDxe.c

   1 /** @file
   2
   3   IoMmuDxe driver installs EDKII_IOMMU_PROTOCOL to provide the support for DMA
   4   operations when SEV is enabled.
   5
   6   Copyright (c) 2017, AMD Inc. All rights reserved.<BR>
   7
   8   This program and the accompanying materials are licensed and made available
   9   under the terms and conditions of the BSD License which accompanies this
  10   distribution.  The full text of the license may be found at
  11   http://opensource.org/licenses/bsd-license.php
  12
  13   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  14   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  15
  16 **/
  17
  18 #include <PiDxe.h>
  19
  20 #include <Library/BaseLib.h>
  21 #include <Library/DebugLib.h>
  22 #include <Library/BaseMemoryLib.h>
  23 #include <Library/MemoryAllocationLib.h>
  24 #include <Library/UefiBootServicesTableLib.h>
  25 #include <Library/MemEncryptSevLib.h>
  26
  27 #include "AmdSevIoMmu.h"
  28
  29 EFI_STATUS
  30 EFIAPI
  31 IoMmuDxeEntryPoint (
  32   IN EFI_HANDLE         ImageHandle,
  33   IN EFI_SYSTEM_TABLE   *SystemTable
  34   )
  35 {
  36   EFI_STATUS    Status;
  37   EFI_HANDLE    Handle;
  38
  39   //
  40   // When SEV is enabled, install IoMmu protocol otherwise install the
  41   // placeholder protocol so that other dependent module can run.
  42   //
  43   if (MemEncryptSevIsEnabled ()) {
  44     Status = AmdSevInstallIoMmuProtocol ();
  45   } else {
  46     Handle = NULL;
  47
  48     Status = gBS->InstallMultipleProtocolInterfaces (
  49                   &Handle,
  50                   &gIoMmuAbsentProtocolGuid,
  51                   NULL, NULL);
  52   }
  53
  54   return Status;
  55 }