/** @file

  Secure Encrypted Virtualization (SEV) library helper function

  Copyright (c) 2017 - 2020, AMD Incorporated. All rights reserved.<BR>
  Copyright (c) Microsoft Corporation.

  SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include <Uefi.h>
#include <Library/MemEncryptSevLib.h>

/**
  Returns a boolean to indicate whether SEV-SNP is enabled.

  @retval TRUE           SEV-SNP is enabled
  @retval FALSE          SEV-SNP is not enabled
**/
BOOLEAN
EFIAPI
MemEncryptSevSnpIsEnabled (
  VOID
  )
{
  return FALSE;
}

/**
  Returns a boolean to indicate whether SEV-ES is enabled.

  @retval TRUE           SEV-ES is enabled
  @retval FALSE          SEV-ES is not enabled
**/
BOOLEAN
EFIAPI
MemEncryptSevEsIsEnabled (
  VOID
  )
{
  return FALSE;
}

/**
  Returns a boolean to indicate whether SEV is enabled.

  @retval TRUE           SEV is enabled
  @retval FALSE          SEV is not enabled
**/
BOOLEAN
EFIAPI
MemEncryptSevIsEnabled (
  VOID
  )
{
  return FALSE;
}

/**
  This function clears memory encryption bit for the memory region specified by
  BaseAddress and NumPages from the current page table context.

  @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use
                                      current CR3)
  @param[in]  BaseAddress             The physical address that is the start
                                      address of a memory region.
  @param[in]  NumPages                The number of pages from start memory
                                      region.

  @retval RETURN_SUCCESS              The attributes were cleared for the
                                      memory region.
  @retval RETURN_INVALID_PARAMETER    Number of pages is zero.
  @retval RETURN_UNSUPPORTED          Clearing the memory encryption attribute
                                      is not supported
**/
RETURN_STATUS
EFIAPI
MemEncryptSevClearPageEncMask (
  IN PHYSICAL_ADDRESS  Cr3BaseAddress,
  IN PHYSICAL_ADDRESS  BaseAddress,
  IN UINTN             NumPages
  )
{
  return RETURN_UNSUPPORTED;
}

/**
  This function sets memory encryption bit for the memory region specified by
  BaseAddress and NumPages from the current page table context.

  @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use
                                      current CR3)
  @param[in]  BaseAddress             The physical address that is the start
                                      address of a memory region.
  @param[in]  NumPages                The number of pages from start memory
                                      region.

  @retval RETURN_SUCCESS              The attributes were set for the memory
                                      region.
  @retval RETURN_INVALID_PARAMETER    Number of pages is zero.
  @retval RETURN_UNSUPPORTED          Setting the memory encryption attribute
                                      is not supported
**/
RETURN_STATUS
EFIAPI
MemEncryptSevSetPageEncMask (
  IN PHYSICAL_ADDRESS  Cr3BaseAddress,
  IN PHYSICAL_ADDRESS  BaseAddress,
  IN UINTN             NumPages
  )
{
  return RETURN_UNSUPPORTED;
}

/**
  Locate the page range that covers the initial (pre-SMBASE-relocation) SMRAM
  Save State Map.

  @param[out] BaseAddress     The base address of the lowest-address page that
                              covers the initial SMRAM Save State Map.

  @param[out] NumberOfPages   The number of pages in the page range that covers
                              the initial SMRAM Save State Map.

  @retval RETURN_SUCCESS      BaseAddress and NumberOfPages have been set on
                              output.

  @retval RETURN_UNSUPPORTED  SMM is unavailable.
**/
RETURN_STATUS
EFIAPI
MemEncryptSevLocateInitialSmramSaveStateMapPages (
  OUT UINTN  *BaseAddress,
  OUT UINTN  *NumberOfPages
  )
{
  return RETURN_UNSUPPORTED;
}

/**
  Returns the SEV encryption mask.

  @return  The SEV pagtable encryption mask
**/
UINT64
EFIAPI
MemEncryptSevGetEncryptionMask (
  VOID
  )
{
  return 0;
}

/**
  Returns a boolean to indicate whether DebugVirtualization is enabled.

  @retval TRUE           DebugVirtualization is enabled
  @retval FALSE          DebugVirtualization is not enabled
**/
BOOLEAN
EFIAPI
MemEncryptSevEsDebugVirtualizationIsEnabled (
  VOID
  )
{
  return FALSE;
}

/**
  Returns the encryption state of the specified virtual address range.

  @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use
                                      current CR3)
  @param[in]  BaseAddress             Base address to check
  @param[in]  Length                  Length of virtual address range

  @retval MemEncryptSevAddressRangeUnencrypted  Address range is mapped
                                                unencrypted
  @retval MemEncryptSevAddressRangeEncrypted    Address range is mapped
                                                encrypted
  @retval MemEncryptSevAddressRangeMixed        Address range is mapped mixed
  @retval MemEncryptSevAddressRangeError        Address range is not mapped
**/
MEM_ENCRYPT_SEV_ADDRESS_RANGE_STATE
EFIAPI
MemEncryptSevGetAddressRangeState (
  IN PHYSICAL_ADDRESS  Cr3BaseAddress,
  IN PHYSICAL_ADDRESS  BaseAddress,
  IN UINTN             Length
  )
{
  return MemEncryptSevAddressRangeUnencrypted;
}

/**
  This function clears memory encryption bit for the MMIO region specified by
  BaseAddress and NumPages.

  @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use
                                      current CR3)
  @param[in]  BaseAddress             The physical address that is the start
                                      address of a MMIO region.
  @param[in]  NumPages                The number of pages from start memory
                                      region.

  @retval RETURN_SUCCESS              The attributes were cleared for the
                                      memory region.
  @retval RETURN_INVALID_PARAMETER    Number of pages is zero.
  @retval RETURN_UNSUPPORTED          Clearing the memory encryption attribute
                                      is not supported
**/
RETURN_STATUS
EFIAPI
MemEncryptSevClearMmioPageEncMask (
  IN PHYSICAL_ADDRESS  Cr3BaseAddress,
  IN PHYSICAL_ADDRESS  BaseAddress,
  IN UINTN             NumPages
  )
{
  return RETURN_UNSUPPORTED;
}

/**
  Pre-validate the system RAM when SEV-SNP is enabled in the guest VM.

  @param[in]  BaseAddress             Base address
  @param[in]  NumPages                Number of pages starting from the base address

**/
VOID
EFIAPI
MemEncryptSevSnpPreValidateSystemRam (
  IN PHYSICAL_ADDRESS  BaseAddress,
  IN UINTN             NumPages
  )
{
  //
  // Do nothing
  //
}