VirtualMemory.h

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#ifndef VIRTUAL_MEMORY_H
#define VIRTUAL_MEMORY_H
 
#pragma pack(push, 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;  // Combines with CD, WT and MTRR to define true caching type
    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;  // Combines with CD, WT and MTRR to define true caching type
    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_2M_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;  // Combines with CD, WT and MTRR to define true caching type
    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;
 
//
// PAT index bits.
//
typedef union {
  struct {
    UINT8    WriteThrough  : 1;          // 0 = Write-Back caching, 1=Write-Through caching
    UINT8    CacheDisabled : 1;          // 0 = Cached, 1=Non-Cached
    UINT8    PAT           : 1;          // Combines with CD, WT and MTRR to define true caching type
    UINT8    Reserved      : 5;          // Reserved
  } Bits;
  UINT8    Index;
} PAT_INDEX;
 
typedef union {
  struct {
    UINT64    PhysPgOffset : 12;      // 0 = Physical Page Offset
    UINT64    PTOffset     : 9;       // 0 = Page Table Offset
    UINT64    PDOffset     : 9;       // 0 = Page Directory Offset
    UINT64    PDPOffset    : 9;       // 0 = Page Directory Pointer Offset
    UINT64    PML4Offset   : 9;       // 0 = Page Map Level 4 Offset
    UINT64    SignExtend   : 16;      // 0 = Sign Extend
  } Pg4K;
  struct {
    UINT64    PhysPgOffset : 21;      // 0 = Physical Page Offset
    UINT64    PDOffset     : 9;       // 0 = Page Directory Offset
    UINT64    PDPOffset    : 9;       // 0 = Page Directory Pointer Offset
    UINT64    PML4Offset   : 9;       // 0 = Page Map Level 4 Offset
    UINT64    SignExtend   : 16;      // 0 = Sign Extend
  } Pg2M;
  struct {
    UINT64    PhysPgOffset : 30;      // 0 = Physical Page Offset
    UINT64    PDPOffset    : 9;       // 0 = Page Directory Pointer Offset
    UINT64    PML4Offset   : 9;       // 0 = Page Map Level 4 Offset
    UINT64    SignExtend   : 16;      // 0 = Sign Extend
  } Pg1G;
  UINT64    Uint64;
} VIRTUAL_ADDR;
 
#define VA_FIX_SIGN_EXTEND(VA)  ((VA).Pg4K.SignExtend = ((VA).Pg4K.PML4Offset & 0x100U) ? 0xFFFFU : 0U);
 
#pragma pack(pop)
 
#define CR0_WP  BIT16
 
#define CR3_ADDR_MASK  0x000FFFFFFFFFF000ull
#define CR3_FLAG_PWT   0x0000000000000008ull
#define CR3_FLAG_PCD   0x0000000000000010ull
 
#define PAGING_4K_ADDRESS_MASK_64  0x000FFFFFFFFFF000ull
#define PAGING_2M_ADDRESS_MASK_64  0x000FFFFFFFE00000ull
#define PAGING_1G_ADDRESS_MASK_64  0x000FFFFFC0000000ull
 
#endif // VIRTUAL_MEMORY_H