OvmfPkg: Replace BSD License with BSD+Patent License

[mirror_edk2.git] / OvmfPkg / Library / BaseMemEncryptSevLib / MemEncryptSevLibInternal.c

/** @file\r
\r
  Secure Encrypted Virtualization (SEV) library helper function\r
\r
  Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>\r
\r
  SPDX-License-Identifier: BSD-2-Clause-Patent\r
\r
**/\r
\r
#include <Library/BaseLib.h>\r
#include <Library/DebugLib.h>\r
#include <Library/MemEncryptSevLib.h>\r
#include <Library/PcdLib.h>\r
#include <Register/Amd/Cpuid.h>\r
#include <Register/Amd/Msr.h>\r
#include <Register/Cpuid.h>\r
#include <Register/QemuSmramSaveStateMap.h>\r
#include <Register/SmramSaveStateMap.h>\r
#include <Uefi/UefiBaseType.h>\r
\r
STATIC BOOLEAN mSevStatus = FALSE;\r
STATIC BOOLEAN mSevStatusChecked = FALSE;\r
\r
/**\r
\r
  Returns a boolean to indicate whether SEV is enabled\r
\r
  @retval TRUE           SEV is enabled\r
  @retval FALSE          SEV is not enabled\r
  **/\r
STATIC\r
BOOLEAN\r
EFIAPI\r
InternalMemEncryptSevIsEnabled (\r
  VOID\r
  )\r
{\r
  UINT32                            RegEax;\r
  MSR_SEV_STATUS_REGISTER           Msr;\r
  CPUID_MEMORY_ENCRYPTION_INFO_EAX  Eax;\r
\r
  //\r
  // Check if memory encryption leaf exist\r
  //\r
  AsmCpuid (CPUID_EXTENDED_FUNCTION, &RegEax, NULL, NULL, NULL);\r
  if (RegEax >= CPUID_MEMORY_ENCRYPTION_INFO) {\r
    //\r
    // CPUID Fn8000_001F[EAX] Bit 1 (Sev supported)\r
    //\r
    AsmCpuid (CPUID_MEMORY_ENCRYPTION_INFO, &Eax.Uint32, NULL, NULL, NULL);\r
\r
    if (Eax.Bits.SevBit) {\r
      //\r
      // Check MSR_0xC0010131 Bit 0 (Sev Enabled)\r
      //\r
      Msr.Uint32 = AsmReadMsr32 (MSR_SEV_STATUS);\r
      if (Msr.Bits.SevBit) {\r
        return TRUE;\r
      }\r
    }\r
  }\r
\r
  return FALSE;\r
}\r
\r
/**\r
  Returns a boolean to indicate whether SEV is enabled\r
\r
  @retval TRUE           SEV is enabled\r
  @retval FALSE          SEV is not enabled\r
**/\r
BOOLEAN\r
EFIAPI\r
MemEncryptSevIsEnabled (\r
  VOID\r
  )\r
{\r
  if (mSevStatusChecked) {\r
    return mSevStatus;\r
  }\r
\r
  mSevStatus = InternalMemEncryptSevIsEnabled();\r
  mSevStatusChecked = TRUE;\r
\r
  return mSevStatus;\r
}\r
\r
\r
/**\r
  Locate the page range that covers the initial (pre-SMBASE-relocation) SMRAM\r
  Save State Map.\r
\r
  @param[out] BaseAddress     The base address of the lowest-address page that\r
                              covers the initial SMRAM Save State Map.\r
\r
  @param[out] NumberOfPages   The number of pages in the page range that covers\r
                              the initial SMRAM Save State Map.\r
\r
  @retval RETURN_SUCCESS      BaseAddress and NumberOfPages have been set on\r
                              output.\r
\r
  @retval RETURN_UNSUPPORTED  SMM is unavailable.\r
**/\r
RETURN_STATUS\r
EFIAPI\r
MemEncryptSevLocateInitialSmramSaveStateMapPages (\r
  OUT UINTN *BaseAddress,\r
  OUT UINTN *NumberOfPages\r
  )\r
{\r
  UINTN MapStart;\r
  UINTN MapEnd;\r
  UINTN MapPagesStart; // MapStart rounded down to page boundary\r
  UINTN MapPagesEnd;   // MapEnd rounded up to page boundary\r
  UINTN MapPagesSize;  // difference between MapPagesStart and MapPagesEnd\r
\r
  if (!FeaturePcdGet (PcdSmmSmramRequire)) {\r
    return RETURN_UNSUPPORTED;\r
  }\r
\r
  MapStart      = SMM_DEFAULT_SMBASE + SMRAM_SAVE_STATE_MAP_OFFSET;\r
  MapEnd        = MapStart + sizeof (QEMU_SMRAM_SAVE_STATE_MAP);\r
  MapPagesStart = MapStart & ~(UINTN)EFI_PAGE_MASK;\r
  MapPagesEnd   = ALIGN_VALUE (MapEnd, EFI_PAGE_SIZE);\r
  MapPagesSize  = MapPagesEnd - MapPagesStart;\r
\r
  ASSERT ((MapPagesSize & EFI_PAGE_MASK) == 0);\r
\r
  *BaseAddress   = MapPagesStart;\r
  *NumberOfPages = MapPagesSize >> EFI_PAGE_SHIFT;\r
\r
  return RETURN_SUCCESS;\r
}\r