OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c

   1 /** @file
   2
   3   Secure Encrypted Virtualization (SEV) library helper function
   4
   5   Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>
   6
   7   This program and the accompanying materials are licensed and made available
   8   under the terms and conditions of the BSD License which accompanies this
   9   distribution.  The full text of the license may be found at
  10   http://opensource.org/licenses/bsd-license.php
  11
  12   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  13   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  14
  15 **/
  16
  17 #include <Library/BaseLib.h>
  18 #include <Library/DebugLib.h>
  19 #include <Register/Cpuid.h>
  20 #include <Register/Amd/Cpuid.h>
  21 #include <Register/Amd/Msr.h>
  22 #include <Library/MemEncryptSevLib.h>
  23
  24 /**
  25   This function clears memory encryption bit for the memory region specified
  26   by BaseAddress and Number of pages from the current page table context.
  27
  28   @param[in]  Cr3BaseAddress        Cr3 Base Address (if zero then use current
  29                                     CR3)
  30   @param[in]  BaseAddress           The physical address that is the start
  31                                     address of a memory region.
  32   @param[in]  NumberOfPages         The number of pages from start memory
  33                                     region.
  34   @param[in]  Flush                 Flush the caches before clearing the bit
  35                                     (mostly TRUE except MMIO addresses)
  36
  37   @retval RETURN_SUCCESS            The attributes were cleared for the memory
  38                                     region.
  39   @retval RETURN_INVALID_PARAMETER  Number of pages is zero.
  40   @retval RETURN_UNSUPPORTED        Clearing memory encryption attribute is not
  41                                     supported
  42   **/
  43 RETURN_STATUS
  44 EFIAPI
  45 MemEncryptSevClearPageEncMask (
  46   IN PHYSICAL_ADDRESS         Cr3BaseAddress,
  47   IN PHYSICAL_ADDRESS         BaseAddress,
  48   IN UINTN                    NumberOfPages,
  49   IN BOOLEAN                  Flush
  50   )
  51 {
  52   //
  53   // Memory encryption bit is not accessible in 32-bit mode
  54   //
  55   return RETURN_UNSUPPORTED;
  56 }
  57
  58 /**
  59   This function sets memory encryption bit for the memory region specified by
  60   BaseAddress and Number of pages from the current page table context.
  61
  62   @param[in]  Cr3BaseAddress        Cr3 Base Address (if zero then use current
  63                                     CR3)
  64   @param[in]  BaseAddress           The physical address that is the start
  65                                     address of a memory region.
  66   @param[in]  NumberOfPages         The number of pages from start memory
  67                                     region.
  68   @param[in]  Flush                 Flush the caches before clearing the bit
  69                                     (mostly TRUE except MMIO addresses)
  70
  71   @retval RETURN_SUCCESS            The attributes were set for the memory
  72                                     region.
  73   @retval RETURN_INVALID_PARAMETER  Number of pages is zero.
  74   @retval RETURN_UNSUPPORTED        Clearing memory encryption attribute is not
  75                                     supported
  76   **/
  77 RETURN_STATUS
  78 EFIAPI
  79 MemEncryptSevSetPageEncMask (
  80   IN PHYSICAL_ADDRESS         Cr3BaseAddress,
  81   IN PHYSICAL_ADDRESS         BaseAddress,
  82   IN UINTN                    NumberOfPages,
  83   IN BOOLEAN                  Flush
  84   )
  85 {
  86   //
  87   // Memory encryption bit is not accessible in 32-bit mode
  88   //
  89   return RETURN_UNSUPPORTED;
  90 }