/** @file

  Virtual Memory Management Services to set or clear the memory encryption bit

  Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
  Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>

  SPDX-License-Identifier: BSD-2-Clause-Patent

  Code is derived from MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.h

**/

#ifndef __VIRTUAL_MEMORY__
#define __VIRTUAL_MEMORY__

#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/CacheMaintenanceLib.h>
#include <Library/DebugLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Uefi.h>

#define SYS_CODE64_SEL 0x38

#pragma pack(1)

//
// Page-Map Level-4 Offset (PML4) and
// Page-Directory-Pointer Offset (PDPE) entries 4K & 2MB
//

typedef union {
  struct {
    UINT64  Present:1;                // 0 = Not present in memory,
                                      //   1 = Present in memory
    UINT64  ReadWrite:1;              // 0 = Read-Only, 1= Read/Write
    UINT64  UserSupervisor:1;         // 0 = Supervisor, 1=User
    UINT64  WriteThrough:1;           // 0 = Write-Back caching,
                                      //   1 = Write-Through caching
    UINT64  CacheDisabled:1;          // 0 = Cached, 1=Non-Cached
    UINT64  Accessed:1;               // 0 = Not accessed,
                                      //   1 = Accessed (set by CPU)
    UINT64  Reserved:1;               // Reserved
    UINT64  MustBeZero:2;             // Must Be Zero
    UINT64  Available:3;              // Available for use by system software
    UINT64  PageTableBaseAddress:40;  // Page Table Base Address
    UINT64  AvabilableHigh:11;        // Available for use by system software
    UINT64  Nx:1;                     // No Execute bit
  } Bits;
  UINT64    Uint64;
} PAGE_MAP_AND_DIRECTORY_POINTER;

//
// Page Table Entry 4KB
//
typedef union {
  struct {
    UINT64  Present:1;                // 0 = Not present in memory,
                                      //   1 = Present in memory
    UINT64  ReadWrite:1;              // 0 = Read-Only, 1= Read/Write
    UINT64  UserSupervisor:1;         // 0 = Supervisor, 1=User
    UINT64  WriteThrough:1;           // 0 = Write-Back caching,
                                      //   1 = Write-Through caching
    UINT64  CacheDisabled:1;          // 0 = Cached, 1=Non-Cached
    UINT64  Accessed:1;               // 0 = Not accessed,
                                      //   1 = Accessed (set by CPU)
    UINT64  Dirty:1;                  // 0 = Not Dirty, 1 = written by
                                      //   processor on access to page
    UINT64  PAT:1;                    //
    UINT64  Global:1;                 // 0 = Not global page, 1 = global page
                                      //   TLB not cleared on CR3 write
    UINT64  Available:3;              // Available for use by system software
    UINT64  PageTableBaseAddress:40;  // Page Table Base Address
    UINT64  AvabilableHigh:11;        // Available for use by system software
    UINT64  Nx:1;                     // 0 = Execute Code,
                                      //   1 = No Code Execution
  } Bits;
  UINT64    Uint64;
} PAGE_TABLE_4K_ENTRY;

//
// Page Table Entry 2MB
//
typedef union {
  struct {
    UINT64  Present:1;                // 0 = Not present in memory,
                                      //   1 = Present in memory
    UINT64  ReadWrite:1;              // 0 = Read-Only, 1= Read/Write
    UINT64  UserSupervisor:1;         // 0 = Supervisor, 1=User
    UINT64  WriteThrough:1;           // 0 = Write-Back caching,
                                      //   1=Write-Through caching
    UINT64  CacheDisabled:1;          // 0 = Cached, 1=Non-Cached
    UINT64  Accessed:1;               // 0 = Not accessed,
                                      //   1 = Accessed (set by CPU)
    UINT64  Dirty:1;                  // 0 = Not Dirty, 1 = written by
                                      //   processor on access to page
    UINT64  MustBe1:1;                // Must be 1
    UINT64  Global:1;                 // 0 = Not global page, 1 = global page
                                      //   TLB not cleared on CR3 write
    UINT64  Available:3;              // Available for use by system software
    UINT64  PAT:1;                    //
    UINT64  MustBeZero:8;             // Must be zero;
    UINT64  PageTableBaseAddress:31;  // Page Table Base Address
    UINT64  AvabilableHigh:11;        // Available for use by system software
    UINT64  Nx:1;                     // 0 = Execute Code,
                                      //   1 = No Code Execution
  } Bits;
  UINT64    Uint64;
} PAGE_TABLE_ENTRY;

//
// Page Table Entry 1GB
//
typedef union {
  struct {
    UINT64  Present:1;                // 0 = Not present in memory,
                                      //   1 = Present in memory
    UINT64  ReadWrite:1;              // 0 = Read-Only, 1= Read/Write
    UINT64  UserSupervisor:1;         // 0 = Supervisor, 1=User
    UINT64  WriteThrough:1;           // 0 = Write-Back caching,
                                      //   1 = Write-Through caching
    UINT64  CacheDisabled:1;          // 0 = Cached, 1=Non-Cached
    UINT64  Accessed:1;               // 0 = Not accessed,
                                      //   1 = Accessed (set by CPU)
    UINT64  Dirty:1;                  // 0 = Not Dirty, 1 = written by
                                      //   processor on access to page
    UINT64  MustBe1:1;                // Must be 1
    UINT64  Global:1;                 // 0 = Not global page, 1 = global page
                                      //   TLB not cleared on CR3 write
    UINT64  Available:3;              // Available for use by system software
    UINT64  PAT:1;                    //
    UINT64  MustBeZero:17;            // Must be zero;
    UINT64  PageTableBaseAddress:22;  // Page Table Base Address
    UINT64  AvabilableHigh:11;        // Available for use by system software
    UINT64  Nx:1;                     // 0 = Execute Code,
                                      //   1 = No Code Execution
  } Bits;
  UINT64    Uint64;
} PAGE_TABLE_1G_ENTRY;

#pragma pack()

#define IA32_PG_P                   BIT0
#define IA32_PG_RW                  BIT1
#define IA32_PG_PS                  BIT7

#define PAGING_PAE_INDEX_MASK       0x1FF

#define PAGING_4K_ADDRESS_MASK_64   0x000FFFFFFFFFF000ull
#define PAGING_2M_ADDRESS_MASK_64   0x000FFFFFFFE00000ull
#define PAGING_1G_ADDRESS_MASK_64   0x000FFFFFC0000000ull

#define PAGING_L1_ADDRESS_SHIFT     12
#define PAGING_L2_ADDRESS_SHIFT     21
#define PAGING_L3_ADDRESS_SHIFT     30
#define PAGING_L4_ADDRESS_SHIFT     39

#define PAGING_PML4E_NUMBER         4

#define PAGETABLE_ENTRY_MASK        ((1UL << 9) - 1)
#define PML4_OFFSET(x)              ( (x >> 39) & PAGETABLE_ENTRY_MASK)
#define PDP_OFFSET(x)               ( (x >> 30) & PAGETABLE_ENTRY_MASK)
#define PDE_OFFSET(x)               ( (x >> 21) & PAGETABLE_ENTRY_MASK)
#define PTE_OFFSET(x)               ( (x >> 12) & PAGETABLE_ENTRY_MASK)
#define PAGING_1G_ADDRESS_MASK_64   0x000FFFFFC0000000ull

#define PAGE_TABLE_POOL_ALIGNMENT   BASE_2MB
#define PAGE_TABLE_POOL_UNIT_SIZE   SIZE_2MB
#define PAGE_TABLE_POOL_UNIT_PAGES  \
  EFI_SIZE_TO_PAGES (PAGE_TABLE_POOL_UNIT_SIZE)
#define PAGE_TABLE_POOL_ALIGN_MASK  \
  (~(EFI_PHYSICAL_ADDRESS)(PAGE_TABLE_POOL_ALIGNMENT - 1))

typedef struct {
  VOID            *NextPool;
  UINTN           Offset;
  UINTN           FreePages;
} PAGE_TABLE_POOL;



/**
  This function clears memory encryption bit for the memory region specified by
  PhysicalAddress and Length from the current page table context.

  @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use
                                      current CR3)
  @param[in]  PhysicalAddress         The physical address that is the start
                                      address of a memory region.
  @param[in]  Length                  The length of memory region
  @param[in]  Flush                   Flush the caches before applying the
                                      encryption mask

  @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 encyrption attribute
                                      is not supported
**/
RETURN_STATUS
EFIAPI
InternalMemEncryptSevSetMemoryDecrypted (
  IN  PHYSICAL_ADDRESS        Cr3BaseAddress,
  IN  PHYSICAL_ADDRESS        PhysicalAddress,
  IN  UINTN                   Length,
  IN  BOOLEAN                 Flush
  );

/**
  This function sets memory encryption bit for the memory region specified by
  PhysicalAddress and Length from the current page table context.

  @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use
                                      current CR3)
  @param[in]  PhysicalAddress         The physical address that is the start
                                      address of a memory region.
  @param[in]  Length                  The length of memory region
  @param[in]  Flush                   Flush the caches before applying the
                                      encryption mask

  @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 encyrption attribute
                                      is not supported
**/
RETURN_STATUS
EFIAPI
InternalMemEncryptSevSetMemoryEncrypted (
  IN  PHYSICAL_ADDRESS        Cr3BaseAddress,
  IN  PHYSICAL_ADDRESS        PhysicalAddress,
  IN  UINTN                   Length,
  IN  BOOLEAN                 Flush
  );

#endif