OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c

   1 /** @file
   2
   3   Secure Encrypted Virtualization (SEV) library helper function
   4
   5   Copyright (c) 2017 - 2020, AMD Incorporated. All rights reserved.<BR>
   6
   7   SPDX-License-Identifier: BSD-2-Clause-Patent
   8
   9 **/
  10
  11 #include <Library/BaseLib.h>
  12 #include <Library/DebugLib.h>
  13 #include <Library/MemEncryptSevLib.h>
  14 #include <Register/Amd/Cpuid.h>
  15 #include <Register/Amd/Msr.h>
  16 #include <Register/Cpuid.h>
  17
  18 /**
  19   This function clears memory encryption bit for the memory region specified by
  20   BaseAddress and NumPages from the current page table context.
  21
  22   @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use
  23                                       current CR3)
  24   @param[in]  BaseAddress             The physical address that is the start
  25                                       address of a memory region.
  26   @param[in]  NumPages                The number of pages from start memory
  27                                       region.
  28
  29   @retval RETURN_SUCCESS              The attributes were cleared for the
  30                                       memory region.
  31   @retval RETURN_INVALID_PARAMETER    Number of pages is zero.
  32   @retval RETURN_UNSUPPORTED          Clearing the memory encryption attribute
  33                                       is not supported
  34 **/
  35 RETURN_STATUS
  36 EFIAPI
  37 MemEncryptSevClearPageEncMask (
  38   IN PHYSICAL_ADDRESS  Cr3BaseAddress,
  39   IN PHYSICAL_ADDRESS  BaseAddress,
  40   IN UINTN             NumPages
  41   )
  42 {
  43   //
  44   // Memory encryption bit is not accessible in 32-bit mode
  45   //
  46   return RETURN_UNSUPPORTED;
  47 }
  48
  49 /**
  50   This function sets memory encryption bit for the memory region specified by
  51   BaseAddress and NumPages from the current page table context.
  52
  53   @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use
  54                                       current CR3)
  55   @param[in]  BaseAddress             The physical address that is the start
  56                                       address of a memory region.
  57   @param[in]  NumPages                The number of pages from start memory
  58                                       region.
  59
  60   @retval RETURN_SUCCESS              The attributes were set for the memory
  61                                       region.
  62   @retval RETURN_INVALID_PARAMETER    Number of pages is zero.
  63   @retval RETURN_UNSUPPORTED          Setting the memory encryption attribute
  64                                       is not supported
  65 **/
  66 RETURN_STATUS
  67 EFIAPI
  68 MemEncryptSevSetPageEncMask (
  69   IN PHYSICAL_ADDRESS  Cr3BaseAddress,
  70   IN PHYSICAL_ADDRESS  BaseAddress,
  71   IN UINTN             NumPages
  72   )
  73 {
  74   //
  75   // Memory encryption bit is not accessible in 32-bit mode
  76   //
  77   return RETURN_UNSUPPORTED;
  78 }
  79
  80 /**
  81   Returns the encryption state of the specified virtual address range.
  82
  83   @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use
  84                                       current CR3)
  85   @param[in]  BaseAddress             Base address to check
  86   @param[in]  Length                  Length of virtual address range
  87
  88   @retval MemEncryptSevAddressRangeUnencrypted  Address range is mapped
  89                                                 unencrypted
  90   @retval MemEncryptSevAddressRangeEncrypted    Address range is mapped
  91                                                 encrypted
  92   @retval MemEncryptSevAddressRangeMixed        Address range is mapped mixed
  93   @retval MemEncryptSevAddressRangeError        Address range is not mapped
  94 **/
  95 MEM_ENCRYPT_SEV_ADDRESS_RANGE_STATE
  96 EFIAPI
  97 MemEncryptSevGetAddressRangeState (
  98   IN PHYSICAL_ADDRESS  Cr3BaseAddress,
  99   IN PHYSICAL_ADDRESS  BaseAddress,
 100   IN UINTN             Length
 101   )
 102 {
 103   //
 104   // Memory is always encrypted in 32-bit mode
 105   //
 106   return MemEncryptSevAddressRangeEncrypted;
 107 }
 108
 109 /**
 110   This function clears memory encryption bit for the MMIO region specified by
 111   BaseAddress and NumPages.
 112
 113   @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use
 114                                       current CR3)
 115   @param[in]  BaseAddress             The physical address that is the start
 116                                       address of a MMIO region.
 117   @param[in]  NumPages                The number of pages from start memory
 118                                       region.
 119
 120   @retval RETURN_SUCCESS              The attributes were cleared for the
 121                                       memory region.
 122   @retval RETURN_INVALID_PARAMETER    Number of pages is zero.
 123   @retval RETURN_UNSUPPORTED          Clearing the memory encryption attribute
 124                                       is not supported
 125 **/
 126 RETURN_STATUS
 127 EFIAPI
 128 MemEncryptSevClearMmioPageEncMask (
 129   IN PHYSICAL_ADDRESS  Cr3BaseAddress,
 130   IN PHYSICAL_ADDRESS  BaseAddress,
 131   IN UINTN             NumPages
 132   )
 133 {
 134   //
 135   // Memory encryption bit is not accessible in 32-bit mode
 136   //
 137   return RETURN_UNSUPPORTED;
 138 }
 139
 140 /**
 141   Pre-validate the system RAM when SEV-SNP is enabled in the guest VM.
 142
 143   @param[in]  BaseAddress             Base address
 144   @param[in]  NumPages                Number of pages starting from the base address
 145
 146 **/
 147 VOID
 148 EFIAPI
 149 MemEncryptSevSnpPreValidateSystemRam (
 150   IN PHYSICAL_ADDRESS  BaseAddress,
 151   IN UINTN             NumPages
 152   )
 153 {
 154   ASSERT (FALSE);
 155 }