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
   8   are licensed and made available under the terms and conditions of the BSD
   9   License which accompanies this distribution.  The full text of the license may
  10   be found at 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 CR3)
  29   @param[in]  BaseAddress           The physical address that is the start address
  30                                     of a memory region.
  31   @param[in]  NumberOfPages         The number of pages from start memory region.
  32   @param[in]  Flush                 Flush the caches before clearing the bit
  33                                     (mostly TRUE except MMIO addresses)
  34
  35   @retval RETURN_SUCCESS            The attributes were cleared for the memory region.
  36   @retval RETURN_INVALID_PARAMETER  Number of pages is zero.
  37   @retval RETURN_UNSUPPORTED        Clearing memory encryption attribute is not
  38                                     supported
  39   **/
  40 RETURN_STATUS
  41 EFIAPI
  42 MemEncryptSevClearPageEncMask (
  43   IN PHYSICAL_ADDRESS         Cr3BaseAddress,
  44   IN PHYSICAL_ADDRESS         BaseAddress,
  45   IN UINTN                    NumberOfPages,
  46   IN BOOLEAN                  Flush
  47   )
  48 {
  49   //
  50   // Memory encryption bit is not accessible in 32-bit mode
  51   //
  52   return RETURN_UNSUPPORTED;
  53 }
  54
  55 /**
  56   This function sets memory encryption bit for the memory region specified by
  57   BaseAddress and Number of pages from the current page table context.
  58
  59   @param[in]  Cr3BaseAddress        Cr3 Base Address (if zero then use current CR3)
  60   @param[in]  BaseAddress           The physical address that is the start address
  61                                     of a memory region.
  62   @param[in]  NumberOfPages         The number of pages from start memory region.
  63   @param[in]  Flush                 Flush the caches before clearing the bit
  64                                     (mostly TRUE except MMIO addresses)
  65
  66   @retval RETURN_SUCCESS            The attributes were set for the memory region.
  67   @retval RETURN_INVALID_PARAMETER  Number of pages is zero.
  68   @retval RETURN_UNSUPPORTED        Clearing memory encryption attribute is not
  69                                     supported
  70   **/
  71 RETURN_STATUS
  72 EFIAPI
  73 MemEncryptSevSetPageEncMask (
  74   IN PHYSICAL_ADDRESS         Cr3BaseAddress,
  75   IN PHYSICAL_ADDRESS         BaseAddress,
  76   IN UINTN                    NumberOfPages,
  77   IN BOOLEAN                  Flush
  78   )
  79 {
  80   //
  81   // Memory encryption bit is not accessible in 32-bit mode
  82   //
  83   return RETURN_UNSUPPORTED;
  84 }