Пример #1
0
void disassembler::Jd(const x86_insn *insn)
{
  Bit32s imm32 = (Bit32s) fetch_dword();

  if (insn->is_64) {
    Bit64u imm64 = (Bit32s) imm32;

    if (offset_mode_hex) {
      dis_sprintf(".+0x%08x%08x", GET32H(imm64), GET32L(imm64));
    }
    else {
      dis_sprintf(".%+d", (int) imm32);
    }

    if (db_cs_base != BX_JUMP_TARGET_NOT_REQ) {
      Bit64u target = db_cs_base + db_eip + (Bit64s) imm64;
      dis_sprintf(" (0x%08x%08x)", GET32H(target), GET32L(target));
    }

    return;
  }

  if (offset_mode_hex) {
    dis_sprintf(".+0x%08x", (unsigned) imm32);
  }
  else {
    dis_sprintf(".%+d", (int) imm32);
  }

  if (db_cs_base != BX_JUMP_TARGET_NOT_REQ) {
    Bit32u target = (Bit32u)(db_cs_base + db_eip + (Bit32s) imm32);
    dis_sprintf(" (0x%08x)", target);
  }
}
Пример #2
0
// jump offset
void disassembler::Jb(const x86_insn *insn)
{
  Bit8s imm8 = (Bit8s) fetch_byte();

  if (insn->is_64) {
    Bit64u imm64 = (Bit8s) imm8;

    if (offset_mode_hex) {
      dis_sprintf(".+0x%08x%08x", GET32H(imm64), GET32L(imm64));
    }
    else {
      dis_sprintf(".%+d", (int) imm8);
    }

    if (db_cs_base != BX_JUMP_TARGET_NOT_REQ) {
      Bit64u target = db_eip + imm64;
      target += db_cs_base;
      dis_sprintf(" (0x%08x%08x)", GET32H(target), GET32L(target));
    }

    return;
  }

  if (insn->os_32) {
    Bit32u imm32 = (Bit8s) imm8;

    if (offset_mode_hex) {
      dis_sprintf(".+0x%08x", (unsigned) imm32);
    }
    else {
      dis_sprintf(".%+d", (int) imm8);
    }

    if (db_cs_base != BX_JUMP_TARGET_NOT_REQ) {
      Bit32u target = (Bit32u)(db_cs_base + db_eip + (Bit32s) imm32);
      dis_sprintf(" (0x%08x)", target);
    }
  }
  else {
    Bit16u imm16 = (Bit8s) imm8;

    if (offset_mode_hex) {
      dis_sprintf(".+0x%04x", (unsigned) imm16);
    }
    else {
      dis_sprintf(".%+d", (int) imm8);
    }

    if (db_cs_base != BX_JUMP_TARGET_NOT_REQ) {
      Bit16u target = (Bit16u)((db_eip + (Bit16s) imm16) & 0xffff);
      dis_sprintf(" (0x%08x)", target + db_cs_base);
    }
  }
}
Пример #3
0
void disassembler::Iq(const x86_insn *insn)
{
  Bit64u value = fetch_qword();

  if (! intel_mode) dis_putc('$');
  dis_sprintf("0x%08x%08x", GET32H(value), GET32L(value));
}
Пример #4
0
// direct memory access
void disassembler::OP_O(const x86_insn *insn, unsigned size)
{
  const char *seg;

  if (insn->is_seg_override())
    seg = segment_name[insn->seg_override];
  else
    seg = segment_name[DS_REG];

  print_datasize(size);

  if (insn->as_64) {
    Bit64u imm64 = fetch_qword();
    dis_sprintf("%s:0x%08x%08x", seg, GET32H(imm64), GET32L(imm64));
  }
  else if (insn->as_32) {
    Bit32u imm32 = fetch_dword();
    dis_sprintf("%s:0x%08x", seg, (unsigned) imm32);
  }
  else {
    Bit16u imm16 = fetch_word();
    dis_sprintf("%s:0x%04x", seg, (unsigned) imm16);
  }
}
Пример #5
0
// sign extended immediate
void disassembler::sIdq(const x86_insn *insn)
{
  if (! intel_mode) dis_putc('$');
  Bit64u imm64 = (Bit32s) fetch_dword();
  dis_sprintf ("0x%08x%08x", GET32H(imm64), GET32L(imm64));
}
Пример #6
0
void BX_CPU_C::long_mode_int(Bit8u vector, unsigned soft_int, bx_bool push_error, Bit16u error_code)
{
  bx_descriptor_t gate_descriptor, cs_descriptor;
  bx_selector_t cs_selector;

  // interrupt vector must be within IDT table limits,
  // else #GP(vector*8 + 2 + EXT)
  if ((vector*16 + 15) > BX_CPU_THIS_PTR idtr.limit) {
    BX_ERROR(("interrupt(long mode): vector must be within IDT table limits, IDT.limit = 0x%x", BX_CPU_THIS_PTR idtr.limit));
    exception(BX_GP_EXCEPTION, vector*8 + 2);
  }

  Bit64u desctmp1 = system_read_qword(BX_CPU_THIS_PTR idtr.base + vector*16);
  Bit64u desctmp2 = system_read_qword(BX_CPU_THIS_PTR idtr.base + vector*16 + 8);

  if (desctmp2 & BX_CONST64(0x00001F0000000000)) {
    BX_ERROR(("interrupt(long mode): IDT entry extended attributes DWORD4 TYPE != 0"));
    exception(BX_GP_EXCEPTION, vector*8 + 2);
  }

  Bit32u dword1 = GET32L(desctmp1);
  Bit32u dword2 = GET32H(desctmp1);
  Bit32u dword3 = GET32L(desctmp2);

  parse_descriptor(dword1, dword2, &gate_descriptor);

  if ((gate_descriptor.valid==0) || gate_descriptor.segment)
  {
    BX_ERROR(("interrupt(long mode): gate descriptor is not valid sys seg"));
    exception(BX_GP_EXCEPTION, vector*8 + 2);
  }

  // descriptor AR byte must indicate interrupt gate, trap gate,
  // or task gate, else #GP(vector*8 + 2 + EXT)
  if (gate_descriptor.type != BX_386_INTERRUPT_GATE &&
      gate_descriptor.type != BX_386_TRAP_GATE)
  {
    BX_ERROR(("interrupt(long mode): unsupported gate type %u",
        (unsigned) gate_descriptor.type));
    exception(BX_GP_EXCEPTION, vector*8 + 2);
  }

  // if software interrupt, then gate descripor DPL must be >= CPL,
  // else #GP(vector * 8 + 2 + EXT)
  if (soft_int && gate_descriptor.dpl < CPL)
  {
    BX_ERROR(("interrupt(long mode): soft_int && gate.dpl < CPL"));
    exception(BX_GP_EXCEPTION, vector*8 + 2);
  }

  // Gate must be present, else #NP(vector * 8 + 2 + EXT)
  if (! IS_PRESENT(gate_descriptor)) {
    BX_ERROR(("interrupt(long mode): gate.p == 0"));
    exception(BX_NP_EXCEPTION, vector*8 + 2);
  }

  Bit16u gate_dest_selector = gate_descriptor.u.gate.dest_selector;
  Bit64u gate_dest_offset   = ((Bit64u)dword3 << 32) |
                       gate_descriptor.u.gate.dest_offset;

  unsigned ist = gate_descriptor.u.gate.param_count & 0x7;

  // examine CS selector and descriptor given in gate descriptor
  // selector must be non-null else #GP(EXT)
  if ((gate_dest_selector & 0xfffc) == 0) {
    BX_ERROR(("int_trap_gate(long mode): selector null"));
    exception(BX_GP_EXCEPTION, 0);
  }

  parse_selector(gate_dest_selector, &cs_selector);

  // selector must be within its descriptor table limits
  // else #GP(selector+EXT)
  fetch_raw_descriptor(&cs_selector, &dword1, &dword2, BX_GP_EXCEPTION);
  parse_descriptor(dword1, dword2, &cs_descriptor);

  // descriptor AR byte must indicate code seg
  // and code segment descriptor DPL<=CPL, else #GP(selector+EXT)
  if (cs_descriptor.valid==0 || cs_descriptor.segment==0 ||
      IS_DATA_SEGMENT(cs_descriptor.type) ||
      cs_descriptor.dpl > CPL)
  {
    BX_ERROR(("interrupt(long mode): not accessible or not code segment"));
    exception(BX_GP_EXCEPTION, cs_selector.value & 0xfffc);
  }

  // check that it's a 64 bit segment
  if (! IS_LONG64_SEGMENT(cs_descriptor) || cs_descriptor.u.segment.d_b)
  {
    BX_ERROR(("interrupt(long mode): must be 64 bit segment"));
    exception(BX_GP_EXCEPTION, cs_selector.value & 0xfffc);
  }

  // segment must be present, else #NP(selector + EXT)
  if (! IS_PRESENT(cs_descriptor)) {
    BX_ERROR(("interrupt(long mode): segment not present"));
    exception(BX_NP_EXCEPTION, cs_selector.value & 0xfffc);
  }
 
  Bit64u RSP_for_cpl_x;

  Bit64u old_CS  = BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value;
  Bit64u old_RIP = RIP;
  Bit64u old_SS  = BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].selector.value;
  Bit64u old_RSP = RSP;

  // if code segment is non-conforming and DPL < CPL then
  // INTERRUPT TO INNER PRIVILEGE:
  if (IS_CODE_SEGMENT_NON_CONFORMING(cs_descriptor.type) && cs_descriptor.dpl < CPL)
  {
    BX_DEBUG(("interrupt(long mode): INTERRUPT TO INNER PRIVILEGE"));

    // check selector and descriptor for new stack in current TSS
    if (ist > 0) {
      BX_DEBUG(("interrupt(long mode): trap to IST, vector = %d", ist));
      RSP_for_cpl_x = get_RSP_from_TSS(ist+3);
    }
    else {
      RSP_for_cpl_x = get_RSP_from_TSS(cs_descriptor.dpl);
    }

    // align stack
    RSP_for_cpl_x &= BX_CONST64(0xfffffffffffffff0);

    // push old stack long pointer onto new stack
    write_new_stack_qword_64(RSP_for_cpl_x -  8, cs_descriptor.dpl, old_SS);
    write_new_stack_qword_64(RSP_for_cpl_x - 16, cs_descriptor.dpl, old_RSP);
    write_new_stack_qword_64(RSP_for_cpl_x - 24, cs_descriptor.dpl, read_eflags());
    // push long pointer to return address onto new stack
    write_new_stack_qword_64(RSP_for_cpl_x - 32, cs_descriptor.dpl, old_CS);
    write_new_stack_qword_64(RSP_for_cpl_x - 40, cs_descriptor.dpl, old_RIP);
    RSP_for_cpl_x -= 40;

    if (push_error) {
      RSP_for_cpl_x -= 8;
      write_new_stack_qword_64(RSP_for_cpl_x, cs_descriptor.dpl, error_code);
    }

    // load CS:RIP (guaranteed to be in 64 bit mode)
    branch_far64(&cs_selector, &cs_descriptor, gate_dest_offset, cs_descriptor.dpl);

    // set up null SS descriptor
    load_null_selector(&BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS], cs_descriptor.dpl);
  }
  else if(IS_CODE_SEGMENT_CONFORMING(cs_descriptor.type) || cs_descriptor.dpl==CPL) 
  {
    // if code segment is conforming OR code segment DPL = CPL then
    // INTERRUPT TO SAME PRIVILEGE LEVEL:

    BX_DEBUG(("interrupt(long mode): INTERRUPT TO SAME PRIVILEGE"));

    // check selector and descriptor for new stack in current TSS
    if (ist > 0) {
      BX_DEBUG(("interrupt(long mode): trap to IST, vector = %d", ist));
      RSP_for_cpl_x = get_RSP_from_TSS(ist+3);
    }
    else {
      RSP_for_cpl_x = RSP;
    }

    // align stack
    RSP_for_cpl_x &= BX_CONST64(0xfffffffffffffff0);

    // push flags onto stack
    // push current CS selector onto stack
    // push return offset onto stack
    write_new_stack_qword_64(RSP_for_cpl_x - 8,  cs_descriptor.dpl, old_SS);
    write_new_stack_qword_64(RSP_for_cpl_x - 16, cs_descriptor.dpl, old_RSP);
    write_new_stack_qword_64(RSP_for_cpl_x - 24, cs_descriptor.dpl, read_eflags());
    // push long pointer to return address onto new stack
    write_new_stack_qword_64(RSP_for_cpl_x - 32, cs_descriptor.dpl, old_CS);
    write_new_stack_qword_64(RSP_for_cpl_x - 40, cs_descriptor.dpl, old_RIP);
    RSP_for_cpl_x -= 40;

    if (push_error) {
      RSP_for_cpl_x -= 8;
      write_new_stack_qword_64(RSP_for_cpl_x, cs_descriptor.dpl, error_code);
    }

    // set the RPL field of CS to CPL
    branch_far64(&cs_selector, &cs_descriptor, gate_dest_offset, CPL);
  }
  else {
    BX_ERROR(("interrupt(long mode): bad descriptor type %u (CS.DPL=%u CPL=%u)",
      (unsigned) cs_descriptor.type, (unsigned) cs_descriptor.dpl, (unsigned) CPL));
    exception(BX_GP_EXCEPTION, cs_selector.value & 0xfffc);
  }

  RSP = RSP_for_cpl_x;

  // if interrupt gate then set IF to 0
  if (!(gate_descriptor.type & 1)) // even is int-gate
    BX_CPU_THIS_PTR clear_IF();
  BX_CPU_THIS_PTR clear_TF();
//BX_CPU_THIS_PTR clear_VM(); // VM is clear in long mode
  BX_CPU_THIS_PTR clear_RF();
  BX_CPU_THIS_PTR clear_NT();
}
Пример #7
0
void BX_CPU_C::protected_mode_int(Bit8u vector, unsigned soft_int, bx_bool push_error, Bit16u error_code)
{
  bx_descriptor_t gate_descriptor, cs_descriptor;
  bx_selector_t cs_selector;

  Bit16u raw_tss_selector;
  bx_selector_t   tss_selector;
  bx_descriptor_t tss_descriptor;

  Bit16u gate_dest_selector;
  Bit32u gate_dest_offset;

  // interrupt vector must be within IDT table limits,
  // else #GP(vector*8 + 2 + EXT)
  if ((vector*8 + 7) > BX_CPU_THIS_PTR idtr.limit) {
    BX_ERROR(("interrupt(): vector must be within IDT table limits, IDT.limit = 0x%x", BX_CPU_THIS_PTR idtr.limit));
    exception(BX_GP_EXCEPTION, vector*8 + 2);
  }

  Bit64u desctmp = system_read_qword(BX_CPU_THIS_PTR idtr.base + vector*8);

  Bit32u dword1 = GET32L(desctmp);
  Bit32u dword2 = GET32H(desctmp);

  parse_descriptor(dword1, dword2, &gate_descriptor);

  if ((gate_descriptor.valid==0) || gate_descriptor.segment) {
    BX_ERROR(("interrupt(): gate descriptor is not valid sys seg (vector=0x%02x)", vector));
    exception(BX_GP_EXCEPTION, vector*8 + 2);
  }

  // descriptor AR byte must indicate interrupt gate, trap gate,
  // or task gate, else #GP(vector*8 + 2 + EXT)
  switch (gate_descriptor.type) {
  case BX_TASK_GATE:
  case BX_286_INTERRUPT_GATE:
  case BX_286_TRAP_GATE:
  case BX_386_INTERRUPT_GATE:
  case BX_386_TRAP_GATE:
    break;
  default:
    BX_ERROR(("interrupt(): gate.type(%u) != {5,6,7,14,15}",
      (unsigned) gate_descriptor.type));
    exception(BX_GP_EXCEPTION, vector*8 + 2);
  }

  // if software interrupt, then gate descripor DPL must be >= CPL,
  // else #GP(vector * 8 + 2 + EXT)
  if (soft_int && gate_descriptor.dpl < CPL) {
    BX_ERROR(("interrupt(): soft_int && (gate.dpl < CPL)"));
    exception(BX_GP_EXCEPTION, vector*8 + 2);
  }

  // Gate must be present, else #NP(vector * 8 + 2 + EXT)
  if (! IS_PRESENT(gate_descriptor)) {
    BX_ERROR(("interrupt(): gate not present"));
    exception(BX_NP_EXCEPTION, vector*8 + 2);
  }

  switch (gate_descriptor.type) {
  case BX_TASK_GATE:
    // examine selector to TSS, given in task gate descriptor
    raw_tss_selector = gate_descriptor.u.taskgate.tss_selector;
    parse_selector(raw_tss_selector, &tss_selector);

    // must specify global in the local/global bit,
    //      else #GP(TSS selector)
    if (tss_selector.ti) {
      BX_ERROR(("interrupt(): tss_selector.ti=1 from gate descriptor - #GP(tss_selector)"));
      exception(BX_GP_EXCEPTION, raw_tss_selector & 0xfffc);
    }

    // index must be within GDT limits, else #TS(TSS selector)
    fetch_raw_descriptor(&tss_selector, &dword1, &dword2, BX_GP_EXCEPTION);

    parse_descriptor(dword1, dword2, &tss_descriptor);

    // AR byte must specify available TSS,
    //   else #GP(TSS selector)
    if (tss_descriptor.valid==0 || tss_descriptor.segment) {
      BX_ERROR(("interrupt(): TSS selector points to invalid or bad TSS - #GP(tss_selector)"));
      exception(BX_GP_EXCEPTION, raw_tss_selector & 0xfffc);
    }

    if (tss_descriptor.type!=BX_SYS_SEGMENT_AVAIL_286_TSS &&
        tss_descriptor.type!=BX_SYS_SEGMENT_AVAIL_386_TSS)
    {
      BX_ERROR(("interrupt(): TSS selector points to bad TSS - #GP(tss_selector)"));
      exception(BX_GP_EXCEPTION, raw_tss_selector & 0xfffc);
    }

    // TSS must be present, else #NP(TSS selector)
    if (! IS_PRESENT(tss_descriptor)) {
      BX_ERROR(("interrupt(): TSS descriptor.p == 0"));
      exception(BX_NP_EXCEPTION, raw_tss_selector & 0xfffc);
    }

    // switch tasks with nesting to TSS
    task_switch(0, &tss_selector, &tss_descriptor,
                    BX_TASK_FROM_INT, dword1, dword2);

    RSP_SPECULATIVE;

    // if interrupt was caused by fault with error code
    //   stack limits must allow push of 2 more bytes, else #SS(0)
    // push error code onto stack

    if (push_error) {
      if (tss_descriptor.type >= 9) // TSS386
        push_32(error_code);
      else
        push_16(error_code);
    }

    // instruction pointer must be in CS limit, else #GP(0)
    if (EIP > BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.limit_scaled) {
      BX_ERROR(("interrupt(): EIP > CS.limit"));
      exception(BX_GP_EXCEPTION, 0);
    }

    RSP_COMMIT;

    return;

  case BX_286_INTERRUPT_GATE:
  case BX_286_TRAP_GATE:
  case BX_386_INTERRUPT_GATE:
  case BX_386_TRAP_GATE:
    gate_dest_selector = gate_descriptor.u.gate.dest_selector;
    gate_dest_offset   = gate_descriptor.u.gate.dest_offset;

    // examine CS selector and descriptor given in gate descriptor
    // selector must be non-null else #GP(EXT)
    if ((gate_dest_selector & 0xfffc) == 0) {
      BX_ERROR(("int_trap_gate(): selector null"));
      exception(BX_GP_EXCEPTION, 0);
    }

    parse_selector(gate_dest_selector, &cs_selector);

    // selector must be within its descriptor table limits
    // else #GP(selector+EXT)
    fetch_raw_descriptor(&cs_selector, &dword1, &dword2, BX_GP_EXCEPTION);
    parse_descriptor(dword1, dword2, &cs_descriptor);

    // descriptor AR byte must indicate code seg
    // and code segment descriptor DPL<=CPL, else #GP(selector+EXT)
    if (cs_descriptor.valid==0 || cs_descriptor.segment==0 ||
        IS_DATA_SEGMENT(cs_descriptor.type) ||
        cs_descriptor.dpl > CPL)
    {
      BX_ERROR(("interrupt(): not accessible or not code segment cs=0x%04x", cs_selector.value));
      exception(BX_GP_EXCEPTION, cs_selector.value & 0xfffc);
    }

    // segment must be present, else #NP(selector + EXT)
    if (! IS_PRESENT(cs_descriptor)) {
      BX_ERROR(("interrupt(): segment not present"));
      exception(BX_NP_EXCEPTION, cs_selector.value & 0xfffc);
    }

    // if code segment is non-conforming and DPL < CPL then
    // INTERRUPT TO INNER PRIVILEGE
    if(IS_CODE_SEGMENT_NON_CONFORMING(cs_descriptor.type) && cs_descriptor.dpl < CPL)
    {
      Bit16u old_SS, old_CS, SS_for_cpl_x;
      Bit32u ESP_for_cpl_x, old_EIP, old_ESP;
      bx_descriptor_t ss_descriptor;
      bx_selector_t   ss_selector;
      int is_v8086_mode = v8086_mode();

      BX_DEBUG(("interrupt(): INTERRUPT TO INNER PRIVILEGE"));

      // check selector and descriptor for new stack in current TSS
      get_SS_ESP_from_TSS(cs_descriptor.dpl,
                              &SS_for_cpl_x, &ESP_for_cpl_x);

      if (is_v8086_mode && cs_descriptor.dpl != 0) {
        // if code segment DPL != 0 then #GP(new code segment selector)
        BX_ERROR(("interrupt(): code segment DPL(%d) != 0 in v8086 mode", cs_descriptor.dpl));
        exception(BX_GP_EXCEPTION, cs_selector.value & 0xfffc);
      }

      // Selector must be non-null else #TS(EXT)
      if ((SS_for_cpl_x & 0xfffc) == 0) {
        BX_ERROR(("interrupt(): SS selector null"));
        exception(BX_TS_EXCEPTION, 0); /* TS(ext) */
      }

      // selector index must be within its descriptor table limits
      // else #TS(SS selector + EXT)
      parse_selector(SS_for_cpl_x, &ss_selector);
      // fetch 2 dwords of descriptor; call handles out of limits checks
      fetch_raw_descriptor(&ss_selector, &dword1, &dword2, BX_TS_EXCEPTION);
      parse_descriptor(dword1, dword2, &ss_descriptor);

      // selector rpl must = dpl of code segment,
      // else #TS(SS selector + ext)
      if (ss_selector.rpl != cs_descriptor.dpl) {
        BX_ERROR(("interrupt(): SS.rpl != CS.dpl"));
        exception(BX_TS_EXCEPTION, SS_for_cpl_x & 0xfffc);
      }

      // stack seg DPL must = DPL of code segment,
      // else #TS(SS selector + ext)
      if (ss_descriptor.dpl != cs_descriptor.dpl) {
        BX_ERROR(("interrupt(): SS.dpl != CS.dpl"));
        exception(BX_TS_EXCEPTION, SS_for_cpl_x & 0xfffc);
      }

      // descriptor must indicate writable data segment,
      // else #TS(SS selector + EXT)
      if (ss_descriptor.valid==0 || ss_descriptor.segment==0 ||
           IS_CODE_SEGMENT(ss_descriptor.type) ||
          !IS_DATA_SEGMENT_WRITEABLE(ss_descriptor.type))
      {
        BX_ERROR(("interrupt(): SS is not writable data segment"));
        exception(BX_TS_EXCEPTION, SS_for_cpl_x & 0xfffc);
      }

      // seg must be present, else #SS(SS selector + ext)
      if (! IS_PRESENT(ss_descriptor)) {
        BX_ERROR(("interrupt(): SS not present"));
        exception(BX_SS_EXCEPTION, SS_for_cpl_x & 0xfffc);
      }

      // IP must be within CS segment boundaries, else #GP(0)
      if (gate_dest_offset > cs_descriptor.u.segment.limit_scaled) {
        BX_ERROR(("interrupt(): gate EIP > CS.limit"));
        exception(BX_GP_EXCEPTION, 0);
      }

      old_ESP = ESP;
      old_SS  = BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].selector.value;
      old_EIP = EIP;
      old_CS  = BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value;

      // Prepare new stack segment
      bx_segment_reg_t new_stack;
      new_stack.selector = ss_selector;
      new_stack.cache = ss_descriptor;
      new_stack.selector.rpl = cs_descriptor.dpl;
      // add cpl to the selector value
      new_stack.selector.value = (0xfffc & new_stack.selector.value) |
        new_stack.selector.rpl;

      if (ss_descriptor.u.segment.d_b) {
        Bit32u temp_ESP = ESP_for_cpl_x;

        if (is_v8086_mode)
        {
          if (gate_descriptor.type>=14) { // 386 int/trap gate
            write_new_stack_dword_32(&new_stack, temp_ESP-4,  cs_descriptor.dpl,
                BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].selector.value);
            write_new_stack_dword_32(&new_stack, temp_ESP-8,  cs_descriptor.dpl,
                BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].selector.value);
            write_new_stack_dword_32(&new_stack, temp_ESP-12, cs_descriptor.dpl,
                BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].selector.value);
            write_new_stack_dword_32(&new_stack, temp_ESP-16, cs_descriptor.dpl,
                BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].selector.value);
            temp_ESP -= 16;
          }
          else {
            write_new_stack_word_32(&new_stack, temp_ESP-2, cs_descriptor.dpl,
                BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].selector.value);
            write_new_stack_word_32(&new_stack, temp_ESP-4, cs_descriptor.dpl,
                BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].selector.value);
            write_new_stack_word_32(&new_stack, temp_ESP-6, cs_descriptor.dpl,
                BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].selector.value);
            write_new_stack_word_32(&new_stack, temp_ESP-8, cs_descriptor.dpl,
                BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].selector.value);
            temp_ESP -= 8;
          }
        }

        if (gate_descriptor.type>=14) { // 386 int/trap gate
          // push long pointer to old stack onto new stack
          write_new_stack_dword_32(&new_stack, temp_ESP-4,  cs_descriptor.dpl, old_SS);
          write_new_stack_dword_32(&new_stack, temp_ESP-8,  cs_descriptor.dpl, old_ESP);
          write_new_stack_dword_32(&new_stack, temp_ESP-12, cs_descriptor.dpl, read_eflags());
          write_new_stack_dword_32(&new_stack, temp_ESP-16, cs_descriptor.dpl, old_CS);
          write_new_stack_dword_32(&new_stack, temp_ESP-20, cs_descriptor.dpl, old_EIP);
          temp_ESP -= 20;

          if (push_error) {
            temp_ESP -= 4;
            write_new_stack_dword_32(&new_stack, temp_ESP, cs_descriptor.dpl, error_code);
          }
        }
        else {                          // 286 int/trap gate
          // push long pointer to old stack onto new stack
          write_new_stack_word_32(&new_stack, temp_ESP-2,  cs_descriptor.dpl, old_SS);
          write_new_stack_word_32(&new_stack, temp_ESP-4,  cs_descriptor.dpl, (Bit16u) old_ESP);
          write_new_stack_word_32(&new_stack, temp_ESP-6,  cs_descriptor.dpl, (Bit16u) read_eflags());
          write_new_stack_word_32(&new_stack, temp_ESP-8,  cs_descriptor.dpl, old_CS);
          write_new_stack_word_32(&new_stack, temp_ESP-10, cs_descriptor.dpl, (Bit16u) old_EIP);
          temp_ESP -= 10;

          if (push_error) {
            temp_ESP -= 2;
            write_new_stack_word_32(&new_stack, temp_ESP, cs_descriptor.dpl, error_code);
          }
        }

        ESP = temp_ESP;
      }
      else {
        Bit16u temp_SP = (Bit16u) ESP_for_cpl_x;

        if (is_v8086_mode)
        {
          if (gate_descriptor.type>=14) { // 386 int/trap gate
            write_new_stack_dword_32(&new_stack, (Bit16u)(temp_SP-4),  cs_descriptor.dpl,
                BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].selector.value);
            write_new_stack_dword_32(&new_stack, (Bit16u)(temp_SP-8),  cs_descriptor.dpl,
                BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].selector.value);
            write_new_stack_dword_32(&new_stack, (Bit16u)(temp_SP-12), cs_descriptor.dpl,
                BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].selector.value);
            write_new_stack_dword_32(&new_stack, (Bit16u)(temp_SP-16), cs_descriptor.dpl,
                BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].selector.value);
            temp_SP -= 16;
          }
          else {
            write_new_stack_word_32(&new_stack, (Bit16u)(temp_SP-2), cs_descriptor.dpl,
                BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].selector.value);
            write_new_stack_word_32(&new_stack, (Bit16u)(temp_SP-4), cs_descriptor.dpl,
                BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].selector.value);
            write_new_stack_word_32(&new_stack, (Bit16u)(temp_SP-6), cs_descriptor.dpl,
                BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].selector.value);
            write_new_stack_word_32(&new_stack, (Bit16u)(temp_SP-8), cs_descriptor.dpl,
                BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].selector.value);
            temp_SP -= 8;
          }
        }

        if (gate_descriptor.type>=14) { // 386 int/trap gate
          // push long pointer to old stack onto new stack
          write_new_stack_dword_32(&new_stack, (Bit16u)(temp_SP-4),  cs_descriptor.dpl, old_SS);
          write_new_stack_dword_32(&new_stack, (Bit16u)(temp_SP-8),  cs_descriptor.dpl, old_ESP);
          write_new_stack_dword_32(&new_stack, (Bit16u)(temp_SP-12), cs_descriptor.dpl, read_eflags());
          write_new_stack_dword_32(&new_stack, (Bit16u)(temp_SP-16), cs_descriptor.dpl, old_CS);
          write_new_stack_dword_32(&new_stack, (Bit16u)(temp_SP-20), cs_descriptor.dpl, old_EIP);
          temp_SP -= 20;

          if (push_error) {
            temp_SP -= 4;
            write_new_stack_dword_32(&new_stack, temp_SP, cs_descriptor.dpl, error_code);
          }
        }
        else {                          // 286 int/trap gate
          // push long pointer to old stack onto new stack
          write_new_stack_word_32(&new_stack, (Bit16u)(temp_SP-2),  cs_descriptor.dpl, old_SS);
          write_new_stack_word_32(&new_stack, (Bit16u)(temp_SP-4),  cs_descriptor.dpl, (Bit16u) old_ESP);
          write_new_stack_word_32(&new_stack, (Bit16u)(temp_SP-6),  cs_descriptor.dpl, (Bit16u) read_eflags());
          write_new_stack_word_32(&new_stack, (Bit16u)(temp_SP-8),  cs_descriptor.dpl, old_CS);
          write_new_stack_word_32(&new_stack, (Bit16u)(temp_SP-10), cs_descriptor.dpl, (Bit16u) old_EIP);
          temp_SP -= 10;

          if (push_error) {
            temp_SP -= 2;
            write_new_stack_word_32(&new_stack, temp_SP, cs_descriptor.dpl, error_code);
          }
        }

        SP = temp_SP;
      }

      // load new CS:eIP values from gate
      // set CPL to new code segment DPL
      // set RPL of CS to CPL
      load_cs(&cs_selector, &cs_descriptor, cs_descriptor.dpl);

      // load new SS:eSP values from TSS
      load_ss(&ss_selector, &ss_descriptor, cs_descriptor.dpl);

      if (is_v8086_mode)
      {
        BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].cache.valid = 0;
        BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].selector.value = 0;
        BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].cache.valid = 0;
        BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].selector.value = 0;
        BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].cache.valid = 0;
        BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].selector.value = 0;
        BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].cache.valid = 0;
        BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].selector.value = 0;
      }
    }
    else
    {
      BX_DEBUG(("interrupt(): INTERRUPT TO SAME PRIVILEGE"));

      if (v8086_mode() && (IS_CODE_SEGMENT_CONFORMING(cs_descriptor.type) || cs_descriptor.dpl != 0)) {
        // if code segment DPL != 0 then #GP(new code segment selector)
        BX_ERROR(("interrupt(): code segment conforming or DPL(%d) != 0 in v8086 mode", cs_descriptor.dpl));
        exception(BX_GP_EXCEPTION, cs_selector.value & 0xfffc);
      }

      // EIP must be in CS limit else #GP(0)
      if (gate_dest_offset > cs_descriptor.u.segment.limit_scaled) {
        BX_ERROR(("interrupt(): IP > CS descriptor limit"));
        exception(BX_GP_EXCEPTION, 0);
      }

      // push flags onto stack
      // push current CS selector onto stack
      // push return offset onto stack
      if (gate_descriptor.type >= 14) { // 386 gate
        push_32(read_eflags());
        push_32(BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value);
        push_32(EIP);
        if (push_error)
          push_32(error_code);
      }
      else { // 286 gate
        push_16((Bit16u) read_eflags());
        push_16(BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value);
        push_16(IP);
        if (push_error)
          push_16(error_code);
      }

      // load CS:IP from gate
      // load CS descriptor
      // set the RPL field of CS to CPL
      load_cs(&cs_selector, &cs_descriptor, CPL);
    }

    EIP = gate_dest_offset;

    // if interrupt gate then set IF to 0
    if (!(gate_descriptor.type & 1)) // even is int-gate
      BX_CPU_THIS_PTR clear_IF();
    BX_CPU_THIS_PTR clear_TF();
    BX_CPU_THIS_PTR clear_NT();
    BX_CPU_THIS_PTR clear_VM();
    BX_CPU_THIS_PTR clear_RF();
    return;

  default:
    BX_PANIC(("bad descriptor type in interrupt()!"));
    break;
  }
}
Пример #8
0
BX_CPU_C::call_gate64(bx_selector_t *gate_selector)
{
  bx_selector_t cs_selector;
  Bit32u dword1, dword2, dword3;
  bx_descriptor_t cs_descriptor;
  bx_descriptor_t gate_descriptor;

  // examine code segment selector in call gate descriptor
  BX_DEBUG(("call_gate64: CALL 64bit call gate"));

  fetch_raw_descriptor_64(gate_selector, &dword1, &dword2, &dword3, BX_GP_EXCEPTION);
  parse_descriptor(dword1, dword2, &gate_descriptor);

  Bit16u dest_selector = gate_descriptor.u.gate.dest_selector;
  // selector must not be null else #GP(0)
  if ((dest_selector & 0xfffc) == 0) {
    BX_ERROR(("call_gate64: selector in gate null"));
    exception(BX_GP_EXCEPTION, 0, 0);
  }

  parse_selector(dest_selector, &cs_selector);
  // selector must be within its descriptor table limits,
  //   else #GP(code segment selector)
  fetch_raw_descriptor(&cs_selector, &dword1, &dword2, BX_GP_EXCEPTION);
  parse_descriptor(dword1, dword2, &cs_descriptor);

  // find the RIP in the gate_descriptor
  Bit64u new_RIP = gate_descriptor.u.gate.dest_offset;
  new_RIP |= ((Bit64u)dword3 << 32);

  // AR byte of selected descriptor must indicate code segment,
  //   else #GP(code segment selector)
  // DPL of selected descriptor must be <= CPL,
  // else #GP(code segment selector)
  if (cs_descriptor.valid==0 || cs_descriptor.segment==0 ||
      IS_DATA_SEGMENT(cs_descriptor.type) ||
      cs_descriptor.dpl > CPL)
  {
    BX_ERROR(("call_gate64: selected descriptor is not code"));
    exception(BX_GP_EXCEPTION, dest_selector & 0xfffc, 0);
  }

  // In long mode, only 64-bit call gates are allowed, and they must point
  // to 64-bit code segments, else #GP(selector)
  if (! IS_LONG64_SEGMENT(cs_descriptor) || cs_descriptor.u.segment.d_b)
  {
    BX_ERROR(("call_gate64: not 64-bit code segment in call gate 64"));
    exception(BX_GP_EXCEPTION, dest_selector & 0xfffc, 0);
  }

  // code segment must be present else #NP(selector)
  if (! IS_PRESENT(cs_descriptor)) {
    BX_ERROR(("call_gate64: code segment not present !"));
    exception(BX_NP_EXCEPTION, dest_selector & 0xfffc, 0);
  }

  Bit64u old_CS  = BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value;
  Bit64u old_RIP = RIP;

  // CALL GATE TO MORE PRIVILEGE
  // if non-conforming code segment and DPL < CPL then
  if (IS_CODE_SEGMENT_NON_CONFORMING(cs_descriptor.type) && (cs_descriptor.dpl < CPL))
  {
    Bit64u RSP_for_cpl_x;

    BX_DEBUG(("CALL GATE TO MORE PRIVILEGE LEVEL"));

    // get new RSP for new privilege level from TSS
    get_RSP_from_TSS(cs_descriptor.dpl, &RSP_for_cpl_x);

    Bit64u old_SS  = BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].selector.value;
    Bit64u old_RSP = RSP;

    if (! IsCanonical(RSP_for_cpl_x)) {
      // #SS(selector) when changing priviledge level
      BX_ERROR(("call_gate64: canonical address failure %08x%08x",
         GET32H(RSP_for_cpl_x), GET32L(RSP_for_cpl_x)));
      exception(BX_SS_EXCEPTION, old_SS & 0xfffc, 0);
    }

    // push old stack long pointer onto new stack
    write_new_stack_qword_64(RSP_for_cpl_x -  8, cs_descriptor.dpl, old_SS);
    write_new_stack_qword_64(RSP_for_cpl_x - 16, cs_descriptor.dpl, old_RSP);
    // push long pointer to return address onto new stack
    write_new_stack_qword_64(RSP_for_cpl_x - 24, cs_descriptor.dpl, old_CS);
    write_new_stack_qword_64(RSP_for_cpl_x - 32, cs_descriptor.dpl, old_RIP);
    RSP_for_cpl_x -= 32;

    // prepare new stack null SS selector
    bx_selector_t ss_selector;
    bx_descriptor_t ss_descriptor;

    // set up a null descriptor
    parse_selector(0, &ss_selector);
    parse_descriptor(0, 0, &ss_descriptor);

    // load CS:RIP (guaranteed to be in 64 bit mode)
    branch_far64(&cs_selector, &cs_descriptor, new_RIP, cs_descriptor.dpl);

    // set up null SS descriptor
    load_ss(&ss_selector, &ss_descriptor, cs_descriptor.dpl);
    RSP = RSP_for_cpl_x;
  }
  else
  {
    BX_DEBUG(("CALL GATE TO SAME PRIVILEGE"));

    // push to 64-bit stack, switch to long64 guaranteed
    write_new_stack_qword_64(RSP -  8, CPL, old_CS);
    write_new_stack_qword_64(RSP - 16, CPL, old_RIP);
    RSP -= 16;

    // load CS:RIP (guaranteed to be in 64 bit mode)
    branch_far64(&cs_selector, &cs_descriptor, new_RIP, CPL);
  }
}
Пример #9
0
BX_CPU_C::write_virtual_checks(bx_segment_reg_t *seg, bx_address offset,
                               unsigned length)
{
  Bit32u upper_limit;

#if BX_SUPPORT_X86_64
  if (BX_CPU_THIS_PTR cpu_mode == BX_MODE_LONG_64) {
    // do canonical checks
    if (!IsCanonical(offset)) {
      BX_ERROR(("write_virtual_checks(): canonical Failure 0x%08x:%08x", GET32H(offset), GET32L(offset)));
      exception(int_number(seg), 0, 0);
    }
    seg->cache.valid |= SegAccessWOK;
    return;
  }
#endif
  if (protected_mode()) {
    if (seg->cache.valid==0) {
      BX_DEBUG(("write_virtual_checks(): segment descriptor not valid"));
      exception(int_number(seg), 0, 0);
    }

    if (seg->cache.p == 0) { /* not present */
      BX_ERROR(("write_virtual_checks(): segment not present"));
      exception(int_number(seg), 0, 0);
    }

    switch (seg->cache.type) {
      case 0: case 1:   // read only
      case 4: case 5:   // read only, expand down
      case 8: case 9:   // execute only
      case 10: case 11: // execute/read
      case 12: case 13: // execute only, conforming
      case 14: case 15: // execute/read-only, conforming
        BX_ERROR(("write_virtual_checks(): no write access to seg"));
        exception(int_number(seg), 0, 0);

      case 2: case 3: /* read/write */
        if (offset > (seg->cache.u.segment.limit_scaled - length + 1)
            || (length-1 > seg->cache.u.segment.limit_scaled))
        {
          BX_ERROR(("write_virtual_checks(): write beyond limit, r/w"));
          exception(int_number(seg), 0, 0);
        }
        if (seg->cache.u.segment.limit_scaled >= 7) {
          // Mark cache as being OK type for succeeding writes.  The limit
          // checks still needs to be done though, but is more simple.  We
          // could probably also optimize that out with a flag for the case
          // when limit is the maximum 32bit value.  Limit should accomodate
          // at least a dword, since we subtract from it in the simple
          // limit check in other functions, and we don't want the value to roll.
          // Only normal segments (not expand down) are handled this way.
          seg->cache.valid |= SegAccessWOK;
        }
        break;

      case 6: case 7: /* read/write, expand down */
        if (seg->cache.u.segment.d_b)
          upper_limit = 0xffffffff;
        else
          upper_limit = 0x0000ffff;
        if ((offset <= seg->cache.u.segment.limit_scaled) ||
             (offset > upper_limit) || ((upper_limit - offset) < (length - 1)))
        {
          BX_ERROR(("write_virtual_checks(): write beyond limit, r/w ED"));
          exception(int_number(seg), 0, 0);
        }
        break;
    }

    return;
  }
  else { /* real mode */
    if (offset > (seg->cache.u.segment.limit_scaled - length + 1)
          || (length-1 > seg->cache.u.segment.limit_scaled))
    {
      BX_DEBUG(("write_virtual_checks(): write beyond limit (real mode)"));
      exception(int_number(seg), 0, 0);
    }
    if (seg->cache.u.segment.limit_scaled >= 7) {
      // Mark cache as being OK type for succeeding writes. See notes above.
      seg->cache.valid |= SegAccessWOK;
    }
  }
}
Пример #10
0
BX_CPU_C::read_virtual_checks(bx_segment_reg_t *seg, bx_address offset,
                              unsigned length)
{
  Bit32u upper_limit;

#if BX_SUPPORT_X86_64
  if (BX_CPU_THIS_PTR cpu_mode == BX_MODE_LONG_64) {
    // do canonical checks
    if (!IsCanonical(offset)) {
      BX_ERROR(("read_virtual_checks(): canonical Failure 0x%08x:%08x", GET32H(offset), GET32L(offset)));
      exception(int_number(seg), 0, 0);
    }
    seg->cache.valid |= SegAccessROK;
    return;
  }
#endif
  if (protected_mode()) {
    if (seg->cache.valid==0) {
      BX_DEBUG(("read_virtual_checks(): segment descriptor not valid"));
      exception(int_number(seg), 0, 0);
    }

    if (seg->cache.p == 0) { /* not present */
      BX_ERROR(("read_virtual_checks(): segment not present"));
      exception(int_number(seg), 0, 0);
    }

    switch (seg->cache.type) {
      case 0: case 1: /* read only */
      case 2: case 3: /* read/write */
      case 10: case 11: /* execute/read */
      case 14: case 15: /* execute/read-only, conforming */
        if (offset > (seg->cache.u.segment.limit_scaled - length + 1)
            || (length-1 > seg->cache.u.segment.limit_scaled))
        {
          BX_ERROR(("read_virtual_checks(): read beyond limit"));
          exception(int_number(seg), 0, 0);
        }
        if (seg->cache.u.segment.limit_scaled >= 7) {
          // Mark cache as being OK type for succeeding reads. See notes for
          // write checks; similar code.
          seg->cache.valid |= SegAccessROK;
        }
        break;

      case 4: case 5: /* read only, expand down */
      case 6: case 7: /* read/write, expand down */
        if (seg->cache.u.segment.d_b)
          upper_limit = 0xffffffff;
        else
          upper_limit = 0x0000ffff;
        if ((offset <= seg->cache.u.segment.limit_scaled) ||
             (offset > upper_limit) || ((upper_limit - offset) < (length - 1)))
        {
          BX_ERROR(("read_virtual_checks(): read beyond limit"));
          exception(int_number(seg), 0, 0);
        }
        break;

      case 8: case 9: /* execute only */
      case 12: case 13: /* execute only, conforming */
        /* can't read or write an execute-only segment */
        BX_ERROR(("read_virtual_checks(): execute only"));
        exception(int_number(seg), 0, 0);
    }
    return;
  }
  else { /* real mode */
    if (offset > (seg->cache.u.segment.limit_scaled - length + 1)
        || (length-1 > seg->cache.u.segment.limit_scaled))
    {
      BX_DEBUG(("read_virtual_checks(): read beyond limit (real mode)"));
      exception(int_number(seg), 0, 0);
    }
    if (seg->cache.u.segment.limit_scaled >= 7) {
      // Mark cache as being OK type for succeeding reads. See notes for
      // write checks; similar code.
      seg->cache.valid |= SegAccessROK;
    }
  }
}
Пример #11
0
/* 
   Given a virtual address and a cr3 value, get the PTE (or PDE, for 4MB pages)
   that maps the specified address in the specified process.
   Note: 'ppte' is OPTIONAL (i.e., it can be NULL).
 */
hvm_status MmuGetPageEntry (hvm_address cr3, hvm_address va, PPTE ppte, hvm_bool* pisLargePage)
{
  hvm_status r;
  hvm_phy_address addr;
  PTE p;

  MmuPrint("[MMU] MmuGetPageEntry() cr3: %.8x va: %.8x\n", CR3_ALIGN(cr3), va);

#ifdef ENABLE_PAE
  /* Read PDPTE */
  addr = CR3_ALIGN(cr3) + (VA_TO_PDPTE(va)*sizeof(PTE));
  r = MmuReadPhysicalRegion(addr, &p, sizeof(PTE));
  if (r != HVM_STATUS_SUCCESS) {
    MmuPrint("[MMU] MmuGetPageEntry() cannot read PDPTE from %.8x\n", addr);
    return HVM_STATUS_UNSUCCESSFUL;
  }

  if (!p.Present)
    return HVM_STATUS_UNSUCCESSFUL;
  
  /* Read PDE */
  addr = FRAME_TO_PHY(p.PageBaseAddr) + (VA_TO_PDE(va)*sizeof(PTE));
#else
  /* Read PDE */
  addr = CR3_ALIGN(cr3) + (VA_TO_PDE(va)*sizeof(PTE));
#endif
  
  MmuPrint("[MMU] MmuGetPageEntry() Reading phy %.8x%.8x (NOT large)\n", GET32H(addr), GET32L(addr));
  r = MmuReadPhysicalRegion(addr, &p, sizeof(PTE));
  
  if (r != HVM_STATUS_SUCCESS) {
    MmuPrint("[MMU] MmuGetPageEntry() cannot read PDE from %.8x\n", addr);
    return HVM_STATUS_UNSUCCESSFUL;
  }
  
  MmuPrint("[MMU] MmuGetPageEntry() PDE read. Present? %d Large? %d\n", p.Present, p.LargePage);

  if (!p.Present)
    return HVM_STATUS_UNSUCCESSFUL;
  
  /* If it's present and it's a 4MB page, then this is a hit */
  if(p.LargePage) {
    if (ppte) *ppte = p;
    *pisLargePage = TRUE;
    return HVM_STATUS_SUCCESS;
  }

  /* Read PTE */
  addr = FRAME_TO_PHY(p.PageBaseAddr) + (VA_TO_PTE(va)*sizeof(PTE));
  r = MmuReadPhysicalRegion(addr, &p, sizeof(PTE));

  if (r != HVM_STATUS_SUCCESS) {
    MmuPrint("[MMU] MmuGetPageEntry() cannot read PTE from %.8x\n", addr);
    return HVM_STATUS_UNSUCCESSFUL;
  }

  MmuPrint("[MMU] MmuGetPageEntry() PTE read. Present? %d\n", p.Present);

  if (!p.Present)
    return HVM_STATUS_UNSUCCESSFUL;
  
  if (ppte) *ppte = p;
  *pisLargePage = FALSE;
  
  return HVM_STATUS_SUCCESS;
}