Bochs/bochs/cpu/vmx.cc

/////////////////////////////////////////////////////////////////////////
// $Id$
/////////////////////////////////////////////////////////////////////////
//
//   Copyright (c) 2009-2013 Stanislav Shwartsman
//          Written by Stanislav Shwartsman [sshwarts at sourceforge net]
//
//  This library is free software; you can redistribute it and/or
//  modify it under the terms of the GNU Lesser General Public
//  License as published by the Free Software Foundation; either
//  version 2 of the License, or (at your option) any later version.
//
//  This library is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
//  Lesser General Public License for more details.
//
//  You should have received a copy of the GNU Lesser General Public
//  License along with this library; if not, write to the Free Software
//  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA B 02110-1301 USA
//
/////////////////////////////////////////////////////////////////////////

#define NEED_CPU_REG_SHORTCUTS 1
#include "bochs.h"
#include "cpu.h"
#define LOG_THIS BX_CPU_THIS_PTR

#include "iodev/iodev.h"

#if BX_SUPPORT_VMX

extern unsigned vmcs_field_offset(Bit32u encoding);

#if BX_SUPPORT_VMX >= 2
extern bx_bool isValidMSR_PAT(Bit64u pat_msr);
#endif

////////////////////////////////////////////////////////////
// VMEXIT reasons for BX prints
////////////////////////////////////////////////////////////

static const char *VMX_vmexit_reason_name[] =
{
  "Exception or NMI",
  "External Interrupt",
  "Triple Fault",
  "INIT",
  "SIPI",
  "I/O SMI (SMM Vmexit)",
  "SMI (SMM Vmexit)",
  "Interrupt Window Exiting",
  "NMI Window Exiting",
  "Task Switch",
  "CPUID",
  "GETSEC",
  "HLT",
  "INVD",
  "INVLPG",
  "RDPMC",
  "RDTSC",
  "RSM",
  "VMCALL",
  "VMCLEAR",
  "VMLAUNCH",
  "VMPTRLD",
  "VMPTRST",
  "VMREAD",
  "VMRESUME",
  "VMWRITE",
  "VMXOFF",
  "VMXON",
  "CR Access",
  "DR Access",
  "I/O Instruction",
  "RDMSR",
  "WRMSR",
  "VMEntry failure due to invalid guest state",
  "VMEntry failure due to MSR loading",
  "Reserved",
  "MWAIT",
  "MTF (Monitor Trap Flag)",
  "Reserved",
  "MONITOR",
  "PAUSE",
  "VMEntry failure due to machine check",
  "Reserved",
  "TPR Below Threshold",
  "APIC Access",
  "Virtualized EOI",
  "GDTR/IDTR Access",
  "LDTR/TR Access",
  "EPT Violation",
  "EPT Misconfiguration",
  "INVEPT",
  "RDTSCP",
  "VMX preemption timer expired",
  "INVVPID",
  "WBINVD",
  "XSETBV",
  "APIC Write Trap",
  "RDRAND",
  "INVPCID",
  "VMFUNC",
  "Reserved",
  "RDSEED"
};

////////////////////////////////////////////////////////////
// VMCS access
////////////////////////////////////////////////////////////

void BX_CPU_C::set_VMCSPTR(Bit64u vmxptr)
{
  BX_CPU_THIS_PTR vmcsptr = vmxptr;

  if (vmxptr != BX_INVALID_VMCSPTR)
    BX_CPU_THIS_PTR vmcshostptr = BX_CPU_THIS_PTR getHostMemAddr(vmxptr, BX_WRITE);
  else
    BX_CPU_THIS_PTR vmcshostptr = 0;
}

Bit16u BX_CPP_AttrRegparmN(1) BX_CPU_C::VMread16(unsigned encoding)
{
  Bit16u field;

  unsigned offset = vmcs_field_offset(encoding);
  if(offset >= VMX_VMCS_AREA_SIZE)
    BX_PANIC(("VMread16: can't access encoding 0x%08x, offset=0x%x", encoding, offset));
  bx_phy_address pAddr = BX_CPU_THIS_PTR vmcsptr + offset;

  BX_ASSERT(VMCS_FIELD_WIDTH(encoding) == VMCS_FIELD_WIDTH_16BIT);

  if (BX_CPU_THIS_PTR vmcshostptr) {
    Bit16u *hostAddr = (Bit16u*) (BX_CPU_THIS_PTR vmcshostptr | offset);
    ReadHostWordFromLittleEndian(hostAddr, field);
  }
  else {
    access_read_physical(pAddr, 2, (Bit8u*)(&field));
  }

  BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr, 2, BX_READ, BX_VMCS_ACCESS, (Bit8u*)(&field));

  return field;
}

// write 16-bit value into VMCS 16-bit field
void BX_CPP_AttrRegparmN(2) BX_CPU_C::VMwrite16(unsigned encoding, Bit16u val_16)
{
  unsigned offset = vmcs_field_offset(encoding);
  if(offset >= VMX_VMCS_AREA_SIZE)
    BX_PANIC(("VMwrite16: can't access encoding 0x%08x, offset=0x%x", encoding, offset));
  bx_phy_address pAddr = BX_CPU_THIS_PTR vmcsptr + offset;

  BX_ASSERT(VMCS_FIELD_WIDTH(encoding) == VMCS_FIELD_WIDTH_16BIT);

  if (BX_CPU_THIS_PTR vmcshostptr) {
    Bit16u *hostAddr = (Bit16u*) (BX_CPU_THIS_PTR vmcshostptr | offset);
    pageWriteStampTable.decWriteStamp(pAddr, 2);
    WriteHostWordToLittleEndian(hostAddr, val_16);
  }
  else {
    access_write_physical(pAddr, 2, (Bit8u*)(&val_16));
  }

  BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr, 2, BX_WRITE, BX_VMCS_ACCESS, (Bit8u*)(&val_16));
}

Bit32u BX_CPP_AttrRegparmN(1) BX_CPU_C::VMread32(unsigned encoding)
{
  Bit32u field;

  unsigned offset = vmcs_field_offset(encoding);
  if(offset >= VMX_VMCS_AREA_SIZE)
    BX_PANIC(("VMread32: can't access encoding 0x%08x, offset=0x%x", encoding, offset));
  bx_phy_address pAddr = BX_CPU_THIS_PTR vmcsptr + offset;

  if (BX_CPU_THIS_PTR vmcshostptr) {
    Bit32u *hostAddr = (Bit32u*) (BX_CPU_THIS_PTR vmcshostptr | offset);
    ReadHostDWordFromLittleEndian(hostAddr, field);
  }
  else {
    access_read_physical(pAddr, 4, (Bit8u*)(&field));
  }

  BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr, 4, BX_READ, BX_VMCS_ACCESS, (Bit8u*)(&field));

  return field;
}

// write 32-bit value into VMCS field
void BX_CPP_AttrRegparmN(2) BX_CPU_C::VMwrite32(unsigned encoding, Bit32u val_32)
{
  unsigned offset = vmcs_field_offset(encoding);
  if(offset >= VMX_VMCS_AREA_SIZE)
    BX_PANIC(("VMwrite32: can't access encoding 0x%08x, offset=0x%x", encoding, offset));
  bx_phy_address pAddr = BX_CPU_THIS_PTR vmcsptr + offset;

  if (BX_CPU_THIS_PTR vmcshostptr) {
    Bit32u *hostAddr = (Bit32u*) (BX_CPU_THIS_PTR vmcshostptr | offset);
    pageWriteStampTable.decWriteStamp(pAddr, 4);
    WriteHostDWordToLittleEndian(hostAddr, val_32);
  }
  else {
    access_write_physical(pAddr, 4, (Bit8u*)(&val_32));
  }

  BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr, 4, BX_WRITE, BX_VMCS_ACCESS, (Bit8u*)(&val_32));
}

Bit64u BX_CPP_AttrRegparmN(1) BX_CPU_C::VMread64(unsigned encoding)
{
  BX_ASSERT(!IS_VMCS_FIELD_HI(encoding));

  Bit64u field;

  unsigned offset = vmcs_field_offset(encoding);
  if(offset >= VMX_VMCS_AREA_SIZE)
    BX_PANIC(("VMread64: can't access encoding 0x%08x, offset=0x%x", encoding, offset));
  bx_phy_address pAddr = BX_CPU_THIS_PTR vmcsptr + offset;

  if (BX_CPU_THIS_PTR vmcshostptr) {
    Bit64u *hostAddr = (Bit64u*) (BX_CPU_THIS_PTR vmcshostptr | offset);
    ReadHostQWordFromLittleEndian(hostAddr, field);
  }
  else {
    access_read_physical(pAddr, 8, (Bit8u*)(&field));
  }

  BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr, 8, BX_READ, BX_VMCS_ACCESS, (Bit8u*)(&field));

  return field;
}

// write 64-bit value into VMCS field
void BX_CPP_AttrRegparmN(2) BX_CPU_C::VMwrite64(unsigned encoding, Bit64u val_64)
{
  BX_ASSERT(!IS_VMCS_FIELD_HI(encoding));

  unsigned offset = vmcs_field_offset(encoding);
  if(offset >= VMX_VMCS_AREA_SIZE)
    BX_PANIC(("VMwrite64: can't access encoding 0x%08x, offset=0x%x", encoding, offset));
  bx_phy_address pAddr = BX_CPU_THIS_PTR vmcsptr + offset;

  if (BX_CPU_THIS_PTR vmcshostptr) {
    Bit64u *hostAddr = (Bit64u*) (BX_CPU_THIS_PTR vmcshostptr | offset);
    pageWriteStampTable.decWriteStamp(pAddr, 8);
    WriteHostQWordToLittleEndian(hostAddr, val_64);
  }
  else {
    access_write_physical(pAddr, 8, (Bit8u*)(&val_64));
  }

  BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr, 8, BX_WRITE, BX_VMCS_ACCESS, (Bit8u*)(&val_64));
}

#if BX_SUPPORT_X86_64
BX_CPP_INLINE bx_address BX_CPP_AttrRegparmN(1) BX_CPU_C::VMread_natural(unsigned encoding)
{
  return VMread64(encoding);
}

void BX_CPP_AttrRegparmN(2) BX_CPU_C::VMwrite_natural(unsigned encoding, bx_address val)
{
  VMwrite64(encoding, val);
}
#else
BX_CPP_INLINE bx_address BX_CPP_AttrRegparmN(1) BX_CPU_C::VMread_natural(unsigned encoding)
{
  return VMread32(encoding);
}

void BX_CPP_AttrRegparmN(2) BX_CPU_C::VMwrite_natural(unsigned encoding, bx_address val)
{
  VMwrite32(encoding, val);
}
#endif

////////////////////////////////////////////////////////////
// Shadow VMCS access
////////////////////////////////////////////////////////////

#if BX_SUPPORT_VMX >= 2

Bit16u BX_CPP_AttrRegparmN(1) BX_CPU_C::VMread16_Shadow(unsigned encoding)
{
  unsigned offset = vmcs_field_offset(encoding);
  if(offset >= VMX_VMCS_AREA_SIZE)
    BX_PANIC(("VMread16_Shadow: can't access encoding 0x%08x, offset=0x%x", encoding, offset));

  BX_ASSERT(VMCS_FIELD_WIDTH(encoding) == VMCS_FIELD_WIDTH_16BIT);

  bx_phy_address pAddr = BX_CPU_THIS_PTR vmcs.vmcs_linkptr + offset;
  Bit16u field;
  access_read_physical(pAddr, 2, (Bit8u*)(&field));
  BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr, 2, BX_READ, BX_SHADOW_VMCS_ACCESS, (Bit8u*)(&field));

  return field;
}

// write 16-bit value into shadow VMCS 16-bit field
void BX_CPP_AttrRegparmN(2) BX_CPU_C::VMwrite16_Shadow(unsigned encoding, Bit16u val_16)
{
  unsigned offset = vmcs_field_offset(encoding);
  if(offset >= VMX_VMCS_AREA_SIZE)
    BX_PANIC(("VMwrite16_Shadow: can't access encoding 0x%08x, offset=0x%x", encoding, offset));

  BX_ASSERT(VMCS_FIELD_WIDTH(encoding) == VMCS_FIELD_WIDTH_16BIT);

  bx_phy_address pAddr = BX_CPU_THIS_PTR vmcs.vmcs_linkptr + offset;
  access_write_physical(pAddr, 2, (Bit8u*)(&val_16));
  BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr, 2, BX_WRITE, BX_SHADOW_VMCS_ACCESS, (Bit8u*)(&val_16));
}

Bit32u BX_CPP_AttrRegparmN(1) BX_CPU_C::VMread32_Shadow(unsigned encoding)
{
  unsigned offset = vmcs_field_offset(encoding);
  if(offset >= VMX_VMCS_AREA_SIZE)
    BX_PANIC(("VMread32_Shadow: can't access encoding 0x%08x, offset=0x%x", encoding, offset));

  bx_phy_address pAddr = BX_CPU_THIS_PTR vmcs.vmcs_linkptr + offset;
  Bit32u field;
  access_read_physical(pAddr, 4, (Bit8u*)(&field));
  BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr, 4, BX_READ, BX_SHADOW_VMCS_ACCESS, (Bit8u*)(&field));

  return field;
}

// write 32-bit value into shadow VMCS field
void BX_CPP_AttrRegparmN(2) BX_CPU_C::VMwrite32_Shadow(unsigned encoding, Bit32u val_32)
{
  unsigned offset = vmcs_field_offset(encoding);
  if(offset >= VMX_VMCS_AREA_SIZE)
    BX_PANIC(("VMwrite32_Shadow: can't access encoding 0x%08x, offset=0x%x", encoding, offset));

  bx_phy_address pAddr = BX_CPU_THIS_PTR vmcs.vmcs_linkptr + offset;
  access_write_physical(pAddr, 4, (Bit8u*)(&val_32));
  BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr, 4, BX_WRITE, BX_SHADOW_VMCS_ACCESS, (Bit8u*)(&val_32));
}

Bit64u BX_CPP_AttrRegparmN(1) BX_CPU_C::VMread64_Shadow(unsigned encoding)
{
  BX_ASSERT(!IS_VMCS_FIELD_HI(encoding));

  unsigned offset = vmcs_field_offset(encoding);
  if(offset >= VMX_VMCS_AREA_SIZE)
    BX_PANIC(("VMread64_Shadow: can't access encoding 0x%08x, offset=0x%x", encoding, offset));

  bx_phy_address pAddr = BX_CPU_THIS_PTR vmcs.vmcs_linkptr + offset;
  Bit64u field;
  access_read_physical(pAddr, 8, (Bit8u*)(&field));
  BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr, 8, BX_READ, BX_SHADOW_VMCS_ACCESS, (Bit8u*)(&field));

  return field;
}

// write 64-bit value into shadow VMCS field
void BX_CPP_AttrRegparmN(2) BX_CPU_C::VMwrite64_Shadow(unsigned encoding, Bit64u val_64)
{
  BX_ASSERT(!IS_VMCS_FIELD_HI(encoding));

  unsigned offset = vmcs_field_offset(encoding);
  if(offset >= VMX_VMCS_AREA_SIZE)
    BX_PANIC(("VMwrite64_Shadow: can't access encoding 0x%08x, offset=0x%x", encoding, offset));

  bx_phy_address pAddr = BX_CPU_THIS_PTR vmcs.vmcs_linkptr + offset;
  access_write_physical(pAddr, 8, (Bit8u*)(&val_64));
  BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr, 8, BX_WRITE, BX_SHADOW_VMCS_ACCESS, (Bit8u*)(&val_64));
}

#endif

////////////////////////////////////////////////////////////
// VMfail/VMsucceed
////////////////////////////////////////////////////////////

BX_CPP_INLINE void BX_CPU_C::VMfail(Bit32u error_code)
{
  if ((BX_CPU_THIS_PTR vmcsptr != BX_INVALID_VMCSPTR)) { // executed only if there is a current VMCS
     setEFlagsOSZAPC(EFlagsZFMask);
     VMwrite32(VMCS_32BIT_INSTRUCTION_ERROR, error_code);
  }
  else {
     setEFlagsOSZAPC(EFlagsCFMask);
  }
}

void BX_CPU_C::VMabort(VMX_vmabort_code error_code)
{
  Bit32u abort = error_code;
  bx_phy_address pAddr = BX_CPU_THIS_PTR vmcsptr + VMCS_VMX_ABORT_FIELD_ADDR;
  access_write_physical(pAddr, 4, &abort);
  BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr, 4, BX_WRITE, BX_VMCS_ACCESS, (Bit8u*)(&abort));

#if BX_SUPPORT_VMX >= 2
  // Deactivate VMX preemtion timer
  BX_CPU_THIS_PTR lapic.deactivate_vmx_preemption_timer();
#endif

  shutdown();
}

Bit32u BX_CPU_C::VMXReadRevisionID(bx_phy_address pAddr)
{
  Bit32u revision;
  access_read_physical(pAddr + VMCS_REVISION_ID_FIELD_ADDR, 4, &revision);
  BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr + VMCS_REVISION_ID_FIELD_ADDR, 4,
          BX_READ, BX_VMCS_ACCESS, (Bit8u*)(&revision));

  return revision;
}

#if BX_SUPPORT_VMX >= 2
bx_bool BX_CPU_C::is_eptptr_valid(Bit64u eptptr)
{
  // [2:0] EPT paging-structure memory type
  //       0 = Uncacheable (UC)
  //       6 = Write-back (WB)
  Bit32u memtype = eptptr & 7;
  if (memtype != BX_MEMTYPE_UC && memtype != BX_MEMTYPE_WB) return 0;

  // [5:3] This value is 1 less than the EPT page-walk length
  Bit32u walk_length = (eptptr >> 3) & 7;
  if (walk_length != 3) return 0;

  if (! BX_SUPPORT_VMX_EXTENSION(BX_VMX_EPT_ACCESS_DIRTY)) {
    if (eptptr & 0x40) {
      BX_ERROR(("is_eptptr_valid: EPTPTR A/D enabled when not supported by CPU"));
      return 0;
    }
  }

#define BX_EPTPTR_RESERVED_BITS 0xf80 /* bits 11:5 are reserved */
  if (eptptr & BX_EPTPTR_RESERVED_BITS) {
    BX_ERROR(("is_eptptr_valid: EPTPTR reserved bits set"));
    return 0;
  }

  if (! IsValidPhyAddr(eptptr)) return 0;
  return 1;
}
#endif

BX_CPP_INLINE Bit32u rotate_r(Bit32u val_32)
{
  return (val_32 >> 8) | (val_32 << 24);
}

BX_CPP_INLINE Bit32u rotate_l(Bit32u val_32)
{
  return (val_32 << 8) | (val_32 >> 24);
}

BX_CPP_INLINE Bit32u vmx_from_ar_byte_rd(Bit32u ar_byte)
{
  return rotate_r(ar_byte);
}

BX_CPP_INLINE Bit32u vmx_from_ar_byte_wr(Bit32u ar_byte)
{
  return rotate_l(ar_byte);
}

////////////////////////////////////////////////////////////
// VMenter
////////////////////////////////////////////////////////////

extern struct BxExceptionInfo exceptions_info[];

#define VMENTRY_INJECTING_EVENT(vmentry_interr_info) (vmentry_interr_info & 0x80000000)

#define VMX_CHECKS_USE_MSR_VMX_PINBASED_CTRLS_LO \
  ((BX_SUPPORT_VMX >= 2) ? VMX_MSR_VMX_TRUE_PINBASED_CTRLS_LO : VMX_MSR_VMX_PINBASED_CTRLS_LO)
#define VMX_CHECKS_USE_MSR_VMX_PINBASED_CTRLS_HI \
  ((BX_SUPPORT_VMX >= 2) ? VMX_MSR_VMX_TRUE_PINBASED_CTRLS_HI : VMX_MSR_VMX_PINBASED_CTRLS_HI)

#define VMX_CHECKS_USE_MSR_VMX_PROCBASED_CTRLS_LO \
  ((BX_SUPPORT_VMX >= 2) ? VMX_MSR_VMX_TRUE_PROCBASED_CTRLS_LO : VMX_MSR_VMX_PROCBASED_CTRLS_LO)
#define VMX_CHECKS_USE_MSR_VMX_PROCBASED_CTRLS_HI \
  ((BX_SUPPORT_VMX >= 2) ? VMX_MSR_VMX_TRUE_PROCBASED_CTRLS_HI : VMX_MSR_VMX_PROCBASED_CTRLS_HI)

#define VMX_CHECKS_USE_MSR_VMX_VMEXIT_CTRLS_LO \
  ((BX_SUPPORT_VMX >= 2) ? VMX_MSR_VMX_TRUE_VMEXIT_CTRLS_LO : VMX_MSR_VMX_VMEXIT_CTRLS_LO)
#define VMX_CHECKS_USE_MSR_VMX_VMEXIT_CTRLS_HI \
  ((BX_SUPPORT_VMX >= 2) ? VMX_MSR_VMX_TRUE_VMEXIT_CTRLS_HI : VMX_MSR_VMX_VMEXIT_CTRLS_HI)

#define VMX_CHECKS_USE_MSR_VMX_VMENTRY_CTRLS_LO \
  ((BX_SUPPORT_VMX >= 2) ? VMX_MSR_VMX_TRUE_VMENTRY_CTRLS_LO : VMX_MSR_VMX_VMENTRY_CTRLS_LO)
#define VMX_CHECKS_USE_MSR_VMX_VMENTRY_CTRLS_HI \
  ((BX_SUPPORT_VMX >= 2) ? VMX_MSR_VMX_TRUE_VMENTRY_CTRLS_HI : VMX_MSR_VMX_VMENTRY_CTRLS_HI)

VMX_error_code BX_CPU_C::VMenterLoadCheckVmControls(void)
{
  VMCS_CACHE *vm = &BX_CPU_THIS_PTR vmcs;

  //
  // Load VM-execution control fields to VMCS Cache
  //

  vm->vmexec_ctrls1 = VMread32(VMCS_32BIT_CONTROL_PIN_BASED_EXEC_CONTROLS);
  vm->vmexec_ctrls2 = VMread32(VMCS_32BIT_CONTROL_PROCESSOR_BASED_VMEXEC_CONTROLS);
  if (VMEXIT(VMX_VM_EXEC_CTRL2_SECONDARY_CONTROLS))
    vm->vmexec_ctrls3 = VMread32(VMCS_32BIT_CONTROL_SECONDARY_VMEXEC_CONTROLS);
  else
    vm->vmexec_ctrls3 = 0;
  vm->vm_exceptions_bitmap = VMread32(VMCS_32BIT_CONTROL_EXECUTION_BITMAP);
  vm->vm_pf_mask = VMread32(VMCS_32BIT_CONTROL_PAGE_FAULT_ERR_CODE_MASK);
  vm->vm_pf_match = VMread32(VMCS_32BIT_CONTROL_PAGE_FAULT_ERR_CODE_MATCH);
  vm->vm_cr0_mask = VMread_natural(VMCS_CONTROL_CR0_GUEST_HOST_MASK);
  vm->vm_cr4_mask = VMread_natural(VMCS_CONTROL_CR4_GUEST_HOST_MASK);
  vm->vm_cr0_read_shadow = VMread_natural(VMCS_CONTROL_CR0_READ_SHADOW);
  vm->vm_cr4_read_shadow = VMread_natural(VMCS_CONTROL_CR4_READ_SHADOW);

  vm->vm_cr3_target_cnt = VMread32(VMCS_32BIT_CONTROL_CR3_TARGET_COUNT);
  for (int n=0; n<VMX_CR3_TARGET_MAX_CNT; n++)
    vm->vm_cr3_target_value[n] = VMread_natural(VMCS_CR3_TARGET0 + 2*n);

  //
  // Check VM-execution control fields
  //

  if (~vm->vmexec_ctrls1 & VMX_CHECKS_USE_MSR_VMX_PINBASED_CTRLS_LO) {
     BX_ERROR(("VMFAIL: VMCS EXEC CTRL: VMX pin-based controls allowed 0-settings"));
     return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
  }
  if (vm->vmexec_ctrls1 & ~VMX_CHECKS_USE_MSR_VMX_PINBASED_CTRLS_HI) {
     BX_ERROR(("VMFAIL: VMCS EXEC CTRL: VMX pin-based controls allowed 1-settings"));
     return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
  }

  if (~vm->vmexec_ctrls2 & VMX_CHECKS_USE_MSR_VMX_PROCBASED_CTRLS_LO) {
     BX_ERROR(("VMFAIL: VMCS EXEC CTRL: VMX proc-based controls allowed 0-settings"));
     return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
  }
  if (vm->vmexec_ctrls2 & ~VMX_CHECKS_USE_MSR_VMX_PROCBASED_CTRLS_HI) {
     BX_ERROR(("VMFAIL: VMCS EXEC CTRL: VMX proc-based controls allowed 1-settings"));
     return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
  }

  if (~vm->vmexec_ctrls3 & VMX_MSR_VMX_PROCBASED_CTRLS2_LO) {
     BX_ERROR(("VMFAIL: VMCS EXEC CTRL: VMX secondary proc-based controls allowed 0-settings"));
     return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
  }
  if (vm->vmexec_ctrls3 & ~VMX_MSR_VMX_PROCBASED_CTRLS2_HI) {
     BX_ERROR(("VMFAIL: VMCS EXEC CTRL: VMX secondary proc-based controls allowed 1-settings"));
     return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
  }

  if (vm->vm_cr3_target_cnt > VMX_CR3_TARGET_MAX_CNT) {
     BX_ERROR(("VMFAIL: VMCS EXEC CTRL: too may CR3 targets %d", vm->vm_cr3_target_cnt));
     return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
  }

  if (vm->vmexec_ctrls2 & VMX_VM_EXEC_CTRL2_IO_BITMAPS) {
     vm->io_bitmap_addr[0] = VMread64(VMCS_64BIT_CONTROL_IO_BITMAP_A);
     vm->io_bitmap_addr[1] = VMread64(VMCS_64BIT_CONTROL_IO_BITMAP_B);
     // I/O bitmaps control enabled
     for (int bitmap=0; bitmap < 2; bitmap++) {
       if (! IsValidPageAlignedPhyAddr(vm->io_bitmap_addr[bitmap])) {
         BX_ERROR(("VMFAIL: VMCS EXEC CTRL: I/O bitmap %c phy addr malformed", 'A' + bitmap));
         return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
       }
     }
  }

  if (vm->vmexec_ctrls2 & VMX_VM_EXEC_CTRL2_MSR_BITMAPS) {
     // MSR bitmaps control enabled
     vm->msr_bitmap_addr = (bx_phy_address) VMread64(VMCS_64BIT_CONTROL_MSR_BITMAPS);
     if (! IsValidPageAlignedPhyAddr(vm->msr_bitmap_addr)) {
       BX_ERROR(("VMFAIL: VMCS EXEC CTRL: MSR bitmap phy addr malformed"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }
  }

  if (! (vm->vmexec_ctrls1 & VMX_VM_EXEC_CTRL1_NMI_EXITING)) {
     if (vm->vmexec_ctrls1 & VMX_VM_EXEC_CTRL1_VIRTUAL_NMI) {
       BX_ERROR(("VMFAIL: VMCS EXEC CTRL: misconfigured virtual NMI control"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }
  }

  if (! (vm->vmexec_ctrls1 & VMX_VM_EXEC_CTRL1_VIRTUAL_NMI)) {
     if (vm->vmexec_ctrls2 & VMX_VM_EXEC_CTRL2_NMI_WINDOW_EXITING) {
       BX_ERROR(("VMFAIL: VMCS EXEC CTRL: misconfigured virtual NMI control"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }
  }

#if BX_SUPPORT_VMX >= 2
  if (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_VMCS_SHADOWING) {
     vm->vmread_bitmap_addr = (bx_phy_address) VMread64(VMCS_64BIT_CONTROL_VMREAD_BITMAP_ADDR);
     if (! IsValidPageAlignedPhyAddr(vm->vmread_bitmap_addr)) {
       BX_ERROR(("VMFAIL: VMCS EXEC CTRL: VMREAD bitmap phy addr malformed"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }
     vm->vmwrite_bitmap_addr = (bx_phy_address) VMread64(VMCS_64BIT_CONTROL_VMWRITE_BITMAP_ADDR);
     if (! IsValidPageAlignedPhyAddr(vm->vmwrite_bitmap_addr)) {
       BX_ERROR(("VMFAIL: VMCS EXEC CTRL: VMWRITE bitmap phy addr malformed"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }
  }

  if (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_EPT_VIOLATION_EXCEPTION) {
     vm->ve_info_addr = (bx_phy_address) VMread64(VMCS_64BIT_CONTROL_VE_EXCEPTION_INFO_ADDR);
     if (! IsValidPageAlignedPhyAddr(vm->ve_info_addr)) {
       BX_ERROR(("VMFAIL: VMCS EXEC CTRL: broken #VE information address"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }
  }
#endif

#if BX_SUPPORT_X86_64
  if (vm->vmexec_ctrls2 & VMX_VM_EXEC_CTRL2_TPR_SHADOW) {
     vm->virtual_apic_page_addr = (bx_phy_address) VMread64(VMCS_64BIT_CONTROL_VIRTUAL_APIC_PAGE_ADDR);
     if (! IsValidPageAlignedPhyAddr(vm->virtual_apic_page_addr)) {
       BX_ERROR(("VMFAIL: VMCS EXEC CTRL: virtual apic phy addr malformed"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }

#if BX_SUPPORT_VMX >= 2
     if (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_VIRTUAL_INT_DELIVERY) {
       if (! PIN_VMEXIT(VMX_VM_EXEC_CTRL1_EXTERNAL_INTERRUPT_VMEXIT)) {
         BX_ERROR(("VMFAIL: VMCS EXEC CTRL: virtual interrupt delivery must be set together with external interrupt exiting"));
         return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
       }

       for (int reg = 0; reg < 8; reg++) {
         vm->eoi_exit_bitmap[reg] = VMread32(VMCS_64BIT_CONTROL_EOI_EXIT_BITMAP0 + reg);
       }

       Bit16u guest_interrupt_status = VMread16(VMCS_16BIT_GUEST_INTERRUPT_STATUS);
       vm->rvi = guest_interrupt_status & 0xff;
       vm->svi = guest_interrupt_status >> 8;
     }
     else
#endif
     {
       vm->vm_tpr_threshold = VMread32(VMCS_32BIT_CONTROL_TPR_THRESHOLD);

       if (vm->vm_tpr_threshold & 0xfffffff0) {
         BX_ERROR(("VMFAIL: VMCS EXEC CTRL: TPR threshold too big"));
         return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
       }

       if (! (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_VIRTUALIZE_APIC_ACCESSES)) {
         Bit8u tpr_shadow = (VMX_Read_Virtual_APIC(BX_LAPIC_TPR) >> 4) & 0xf;
         if (vm->vm_tpr_threshold > tpr_shadow) {
           BX_ERROR(("VMFAIL: VMCS EXEC CTRL: TPR threshold > TPR shadow"));
           return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
         }
       }
     }
  }
#if BX_SUPPORT_VMX >= 2
  else { // TPR shadow is disabled
     if (vm->vmexec_ctrls3 & (VMX_VM_EXEC_CTRL3_VIRTUALIZE_X2APIC_MODE |
                              VMX_VM_EXEC_CTRL3_VIRTUALIZE_APIC_REGISTERS |
                              VMX_VM_EXEC_CTRL3_VIRTUAL_INT_DELIVERY))
     {
       BX_ERROR(("VMFAIL: VMCS EXEC CTRL: apic virtualization is enabled without TPR shadow"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }
  }
#endif // BX_SUPPORT_VMX >= 2

  if (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_VIRTUALIZE_APIC_ACCESSES) {
     vm->apic_access_page = (bx_phy_address) VMread64(VMCS_64BIT_CONTROL_APIC_ACCESS_ADDR);
     if (! IsValidPageAlignedPhyAddr(vm->apic_access_page)) {
       BX_ERROR(("VMFAIL: VMCS EXEC CTRL: apic access page phy addr malformed"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }

#if BX_SUPPORT_VMX >= 2
     if (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_VIRTUALIZE_X2APIC_MODE) {
       BX_ERROR(("VMFAIL: VMCS EXEC CTRL: virtualize X2APIC mode enabled together with APIC access virtualization"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }
#endif
  }

#if BX_SUPPORT_VMX >= 2
  if (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_EPT_ENABLE) {
     vm->eptptr = (bx_phy_address) VMread64(VMCS_64BIT_CONTROL_EPTPTR);
     if (! is_eptptr_valid(vm->eptptr)) {
       BX_ERROR(("VMFAIL: VMCS EXEC CTRL: invalid EPTPTR value"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }
  }
  else {
     if (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_UNRESTRICTED_GUEST) {
       BX_ERROR(("VMFAIL: VMCS EXEC CTRL: unrestricted guest without EPT"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }
  }

  if (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_VPID_ENABLE) {
     vm->vpid = VMread16(VMCS_16BIT_CONTROL_VPID);
     if (vm->vpid == 0) {
       BX_ERROR(("VMFAIL: VMCS EXEC CTRL: guest VPID == 0"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }
  }

  if (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_PAUSE_LOOP_VMEXIT) {
     vm->ple.pause_loop_exiting_gap = VMread32(VMCS_32BIT_CONTROL_PAUSE_LOOP_EXITING_GAP);
     vm->ple.pause_loop_exiting_window = VMread32(VMCS_32BIT_CONTROL_PAUSE_LOOP_EXITING_WINDOW);
  }

  if (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_VMFUNC_ENABLE)
    vm->vmfunc_ctrls = VMread64(VMCS_64BIT_CONTROL_VMFUNC_CTRLS);
  else
    vm->vmfunc_ctrls = 0;

  if (vm->vmfunc_ctrls & ~VMX_VMFUNC_CTRL1_SUPPORTED_BITS) {
     BX_ERROR(("VMFAIL: VMCS VM Functions control reserved bits set"));
     return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
  }

  if (vm->vmfunc_ctrls & VMX_VMFUNC_EPTP_SWITCHING_MASK) {

     if ((vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_EPT_ENABLE) == 0) {
       BX_ERROR(("VMFAIL: VMFUNC EPTP-SWITCHING: EPT disabled"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }

     vm->eptp_list_address = VMread64(VMCS_64BIT_CONTROL_EPTP_LIST_ADDRESS);
     if (! IsValidPageAlignedPhyAddr(vm->eptp_list_address)) {
       BX_ERROR(("VMFAIL: VMFUNC EPTP-SWITCHING: eptp list phy addr malformed"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }
  }
#endif

#endif // BX_SUPPORT_X86_64

  //
  // Load VM-exit control fields to VMCS Cache
  //

  vm->vmexit_ctrls = VMread32(VMCS_32BIT_CONTROL_VMEXIT_CONTROLS);
  vm->vmexit_msr_store_cnt = VMread32(VMCS_32BIT_CONTROL_VMEXIT_MSR_STORE_COUNT);
  vm->vmexit_msr_load_cnt = VMread32(VMCS_32BIT_CONTROL_VMEXIT_MSR_LOAD_COUNT);

  //
  // Check VM-exit control fields
  //

  if (~vm->vmexit_ctrls & VMX_CHECKS_USE_MSR_VMX_VMEXIT_CTRLS_LO) {
     BX_ERROR(("VMFAIL: VMCS EXEC CTRL: VMX vmexit controls allowed 0-settings"));
     return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
  }
  if (vm->vmexit_ctrls & ~VMX_CHECKS_USE_MSR_VMX_VMEXIT_CTRLS_HI) {
     BX_ERROR(("VMFAIL: VMCS EXEC CTRL: VMX vmexit controls allowed 1-settings"));
     return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
  }

#if BX_SUPPORT_VMX >= 2
  if ((~vm->vmexec_ctrls1 & VMX_VM_EXEC_CTRL1_VMX_PREEMPTION_TIMER_VMEXIT) && (vm->vmexit_ctrls & VMX_VMEXIT_CTRL1_STORE_VMX_PREEMPTION_TIMER)) {
     BX_ERROR(("VMFAIL: save_VMX_preemption_timer VMEXIT control is set but VMX_preemption_timer VMEXEC control is clear"));
     return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
  }
#endif

  if (vm->vmexit_msr_store_cnt > 0) {
     vm->vmexit_msr_store_addr = VMread64(VMCS_64BIT_CONTROL_VMEXIT_MSR_STORE_ADDR);
     if ((vm->vmexit_msr_store_addr & 0xf) != 0 || ! IsValidPhyAddr(vm->vmexit_msr_store_addr)) {
       BX_ERROR(("VMFAIL: VMCS VMEXIT CTRL: msr store addr malformed"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }

     Bit64u last_byte = vm->vmexit_msr_store_addr + (vm->vmexit_msr_store_cnt * 16) - 1;
     if (! IsValidPhyAddr(last_byte)) {
       BX_ERROR(("VMFAIL: VMCS VMEXIT CTRL: msr store addr too high"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }
  }

  if (vm->vmexit_msr_load_cnt > 0) {
     vm->vmexit_msr_load_addr = VMread64(VMCS_64BIT_CONTROL_VMEXIT_MSR_LOAD_ADDR);
     if ((vm->vmexit_msr_load_addr & 0xf) != 0 || ! IsValidPhyAddr(vm->vmexit_msr_load_addr)) {
       BX_ERROR(("VMFAIL: VMCS VMEXIT CTRL: msr load addr malformed"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }

     Bit64u last_byte = (Bit64u) vm->vmexit_msr_load_addr + (vm->vmexit_msr_load_cnt * 16) - 1;
     if (! IsValidPhyAddr(last_byte)) {
       BX_ERROR(("VMFAIL: VMCS VMEXIT CTRL: msr load addr too high"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }
  }

  //
  // Load VM-entry control fields to VMCS Cache
  //

  vm->vmentry_ctrls = VMread32(VMCS_32BIT_CONTROL_VMENTRY_CONTROLS);
  vm->vmentry_msr_load_cnt = VMread32(VMCS_32BIT_CONTROL_VMENTRY_MSR_LOAD_COUNT);

  //
  // Check VM-entry control fields
  //

  if (~vm->vmentry_ctrls & VMX_CHECKS_USE_MSR_VMX_VMENTRY_CTRLS_LO) {
     BX_ERROR(("VMFAIL: VMCS EXEC CTRL: VMX vmentry controls allowed 0-settings"));
     return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
  }
  if (vm->vmentry_ctrls & ~VMX_CHECKS_USE_MSR_VMX_VMENTRY_CTRLS_HI) {
     BX_ERROR(("VMFAIL: VMCS EXEC CTRL: VMX vmentry controls allowed 1-settings"));
     return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
  }

  if (vm->vmentry_ctrls & VMX_VMENTRY_CTRL1_DEACTIVATE_DUAL_MONITOR_TREATMENT) {
     if (! BX_CPU_THIS_PTR in_smm) {
       BX_ERROR(("VMFAIL: VMENTRY from outside SMM with dual-monitor treatment enabled"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }
  }

  if (vm->vmentry_msr_load_cnt > 0) {
     vm->vmentry_msr_load_addr = VMread64(VMCS_64BIT_CONTROL_VMENTRY_MSR_LOAD_ADDR);
     if ((vm->vmentry_msr_load_addr & 0xf) != 0 || ! IsValidPhyAddr(vm->vmentry_msr_load_addr)) {
       BX_ERROR(("VMFAIL: VMCS VMENTRY CTRL: msr load addr malformed"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }

     Bit64u last_byte = vm->vmentry_msr_load_addr + (vm->vmentry_msr_load_cnt * 16) - 1;
     if (! IsValidPhyAddr(last_byte)) {
       BX_ERROR(("VMFAIL: VMCS VMENTRY CTRL: msr load addr too high"));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }
  }

  //
  // Check VM-entry event injection info
  //

  vm->vmentry_interr_info = VMread32(VMCS_32BIT_CONTROL_VMENTRY_INTERRUPTION_INFO);
  vm->vmentry_excep_err_code = VMread32(VMCS_32BIT_CONTROL_VMENTRY_EXCEPTION_ERR_CODE);
  vm->vmentry_instr_length = VMread32(VMCS_32BIT_CONTROL_VMENTRY_INSTRUCTION_LENGTH);

  if (VMENTRY_INJECTING_EVENT(vm->vmentry_interr_info)) {

     /* the VMENTRY injecting event to the guest */
     unsigned vector = vm->vmentry_interr_info & 0xff;
     unsigned event_type = (vm->vmentry_interr_info >>  8) & 7;
     unsigned push_error = (vm->vmentry_interr_info >> 11) & 1;
     unsigned error_code = push_error ? vm->vmentry_excep_err_code : 0;

     unsigned push_error_reference = 0;
     if (event_type == BX_HARDWARE_EXCEPTION && vector < BX_CPU_HANDLED_EXCEPTIONS)
        push_error_reference = exceptions_info[vector].push_error;

     if (vm->vmentry_interr_info & 0x7ffff000) {
        BX_ERROR(("VMFAIL: VMENTRY broken interruption info field"));
        return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }

     switch (event_type) {
       case BX_EXTERNAL_INTERRUPT:
         break;

       case BX_NMI:
         if (vector != 2) {
           BX_ERROR(("VMFAIL: VMENTRY bad injected event vector %d", vector));
           return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
         }
/*
         // injecting NMI
         if (vm->vmexec_ctrls1 & VMX_VM_EXEC_CTRL1_VIRTUAL_NMI) {
           if (guest.interruptibility_state & BX_VMX_INTERRUPTS_BLOCKED_NMI_BLOCKED) {
             BX_ERROR(("VMFAIL: VMENTRY injected NMI vector when blocked by NMI in interruptibility state", vector));
             return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
           }
         }
*/
         break;

       case BX_HARDWARE_EXCEPTION:
         if (vector > 31) {
           BX_ERROR(("VMFAIL: VMENTRY bad injected event vector %d", vector));
           return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
         }
         break;

       case BX_SOFTWARE_INTERRUPT:
       case BX_PRIVILEGED_SOFTWARE_INTERRUPT:
       case BX_SOFTWARE_EXCEPTION:
         if (vm->vmentry_instr_length == 0 || vm->vmentry_instr_length > 15) {
           BX_ERROR(("VMFAIL: VMENTRY bad injected event instr length"));
           return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
         }
         break;

       case 7: /* MTF */
         if (BX_SUPPORT_VMX_EXTENSION(BX_VMX_MONITOR_TRAP_FLAG)) {
           if (vector != 0) {
             BX_ERROR(("VMFAIL: VMENTRY bad MTF injection with vector=%d", vector));
             return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
           }
         }
         break;

       default:
         BX_ERROR(("VMFAIL: VMENTRY bad injected event type %d", event_type));
         return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }

#if BX_SUPPORT_VMX >= 2
     if (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_UNRESTRICTED_GUEST) {
       unsigned protected_mode_guest = (Bit32u) VMread_natural(VMCS_GUEST_CR0) & BX_CR0_PE_MASK;
       if (! protected_mode_guest) push_error_reference = 0;
     }
#endif

     if (push_error != push_error_reference) {
       BX_ERROR(("VMFAIL: VMENTRY injected event vector %d broken error code", vector));
       return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
     }

     if (push_error) {
        if (error_code & 0xffff0000) {
          BX_ERROR(("VMFAIL: VMENTRY bad error code 0x%08x for injected event %d", error_code, vector));
          return VMXERR_VMENTRY_INVALID_VM_CONTROL_FIELD;
        }
     }
  }

  return VMXERR_NO_ERROR;
}

VMX_error_code BX_CPU_C::VMenterLoadCheckHostState(void)
{
  VMCS_CACHE *vm = &BX_CPU_THIS_PTR vmcs;
  VMCS_HOST_STATE *host_state = &vm->host_state;
  bx_bool x86_64_host = 0, x86_64_guest = 0;

  //
  // VM Host State Checks Related to Address-Space Size
  //

  Bit32u vmexit_ctrls = vm->vmexit_ctrls;
  if (vmexit_ctrls & VMX_VMEXIT_CTRL1_HOST_ADDR_SPACE_SIZE) {
     x86_64_host = 1;
  }
  Bit32u vmentry_ctrls = vm->vmentry_ctrls;
  if (vmentry_ctrls & VMX_VMENTRY_CTRL1_X86_64_GUEST) {
     x86_64_guest = 1;
  }

#if BX_SUPPORT_X86_64
  if (long_mode()) {
     if (! x86_64_host) {
        BX_ERROR(("VMFAIL: VMCS x86-64 host control invalid on VMENTRY"));
        return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
     }
  }
  else
#endif
  {
     if (x86_64_host || x86_64_guest) {
        BX_ERROR(("VMFAIL: VMCS x86-64 guest(%d)/host(%d) controls invalid on VMENTRY", x86_64_guest, x86_64_host));
        return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
     }
  }

  //
  // Load and Check VM Host State to VMCS Cache
  //

  host_state->cr0 = (bx_address) VMread_natural(VMCS_HOST_CR0);
  if (~host_state->cr0 & VMX_MSR_CR0_FIXED0) {
     BX_ERROR(("VMFAIL: VMCS host state invalid CR0 0x%08x", (Bit32u) host_state->cr0));
     return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
  }

  if (host_state->cr0 & ~VMX_MSR_CR0_FIXED1) {
     BX_ERROR(("VMFAIL: VMCS host state invalid CR0 0x%08x", (Bit32u) host_state->cr0));
     return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
  }

  host_state->cr3 = (bx_address) VMread_natural(VMCS_HOST_CR3);
#if BX_SUPPORT_X86_64
  if (! IsValidPhyAddr(host_state->cr3)) {
     BX_ERROR(("VMFAIL: VMCS host state invalid CR3"));
     return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
  }
#endif

  host_state->cr4 = (bx_address) VMread_natural(VMCS_HOST_CR4);
  if (~host_state->cr4 & VMX_MSR_CR4_FIXED0) {
     BX_ERROR(("VMFAIL: VMCS host state invalid CR4 0x" FMT_ADDRX, host_state->cr4));
     return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
  }
  if (host_state->cr4 & ~VMX_MSR_CR4_FIXED1) {
     BX_ERROR(("VMFAIL: VMCS host state invalid CR4 0x" FMT_ADDRX, host_state->cr4));
     return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
  }

  for(int n=0; n<6; n++) {
     host_state->segreg_selector[n] = VMread16(VMCS_16BIT_HOST_ES_SELECTOR + 2*n);
     if (host_state->segreg_selector[n] & 7) {
        BX_ERROR(("VMFAIL: VMCS host segreg %d TI/RPL != 0", n));
        return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
     }
  }

  if (host_state->segreg_selector[BX_SEG_REG_CS] == 0) {
     BX_ERROR(("VMFAIL: VMCS host CS selector 0"));
     return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
  }

  if (! x86_64_host && host_state->segreg_selector[BX_SEG_REG_SS] == 0) {
     BX_ERROR(("VMFAIL: VMCS host SS selector 0"));
     return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
  }

  host_state->tr_selector = VMread16(VMCS_16BIT_HOST_TR_SELECTOR);
  if (! host_state->tr_selector || (host_state->tr_selector & 7) != 0) {
     BX_ERROR(("VMFAIL: VMCS invalid host TR selector"));
     return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
  }

  host_state->tr_base = (bx_address) VMread_natural(VMCS_HOST_TR_BASE);
#if BX_SUPPORT_X86_64
  if (! IsCanonical(host_state->tr_base)) {
     BX_ERROR(("VMFAIL: VMCS host TR BASE non canonical"));
     return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
  }
#endif

  host_state->fs_base = (bx_address) VMread_natural(VMCS_HOST_FS_BASE);
  host_state->gs_base = (bx_address) VMread_natural(VMCS_HOST_GS_BASE);
#if BX_SUPPORT_X86_64
  if (! IsCanonical(host_state->fs_base)) {
     BX_ERROR(("VMFAIL: VMCS host FS BASE non canonical"));
     return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
  }
  if (! IsCanonical(host_state->gs_base)) {
     BX_ERROR(("VMFAIL: VMCS host GS BASE non canonical"));
     return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
  }
#endif

  host_state->gdtr_base = (bx_address) VMread_natural(VMCS_HOST_GDTR_BASE);
  host_state->idtr_base = (bx_address) VMread_natural(VMCS_HOST_IDTR_BASE);
#if BX_SUPPORT_X86_64
  if (! IsCanonical(host_state->gdtr_base)) {
     BX_ERROR(("VMFAIL: VMCS host GDTR BASE non canonical"));
     return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
  }
  if (! IsCanonical(host_state->idtr_base)) {
     BX_ERROR(("VMFAIL: VMCS host IDTR BASE non canonical"));
     return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
  }
#endif

  host_state->sysenter_esp_msr = (bx_address) VMread_natural(VMCS_HOST_IA32_SYSENTER_ESP_MSR);
  host_state->sysenter_eip_msr = (bx_address) VMread_natural(VMCS_HOST_IA32_SYSENTER_EIP_MSR);
  host_state->sysenter_cs_msr = (Bit16u) VMread32(VMCS_32BIT_HOST_IA32_SYSENTER_CS_MSR);

#if BX_SUPPORT_X86_64
  if (! IsCanonical(host_state->sysenter_esp_msr)) {
     BX_ERROR(("VMFAIL: VMCS host SYSENTER_ESP_MSR non canonical"));
     return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
  }

  if (! IsCanonical(host_state->sysenter_eip_msr)) {
     BX_ERROR(("VMFAIL: VMCS host SYSENTER_EIP_MSR non canonical"));
     return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
  }
#endif

#if BX_SUPPORT_VMX >= 2
  if (vmexit_ctrls & VMX_VMEXIT_CTRL1_LOAD_PAT_MSR) {
    host_state->pat_msr = VMread64(VMCS_64BIT_HOST_IA32_PAT);
    if (! isValidMSR_PAT(host_state->pat_msr)) {
      BX_ERROR(("VMFAIL: invalid Memory Type in host MSR_PAT"));
      return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
    }
  }
#endif

  host_state->rsp = (bx_address) VMread_natural(VMCS_HOST_RSP);
  host_state->rip = (bx_address) VMread_natural(VMCS_HOST_RIP);

#if BX_SUPPORT_X86_64

#if BX_SUPPORT_VMX >= 2
  if (vmexit_ctrls & VMX_VMEXIT_CTRL1_LOAD_EFER_MSR) {
    host_state->efer_msr = VMread64(VMCS_64BIT_HOST_IA32_EFER);
    if (host_state->efer_msr & ~((Bit64u) BX_CPU_THIS_PTR efer_suppmask)) {
      BX_ERROR(("VMFAIL: VMCS host EFER reserved bits set !"));
      return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
    }
    bx_bool lme = (host_state->efer_msr >>  8) & 0x1;
    bx_bool lma = (host_state->efer_msr >> 10) & 0x1;
    if (lma != lme || lma != x86_64_host) {
      BX_ERROR(("VMFAIL: VMCS host EFER (0x%08x) inconsistent value !", (Bit32u) host_state->efer_msr));
      return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
    }
  }
#endif

  if (x86_64_host) {
     if ((host_state->cr4 & BX_CR4_PAE_MASK) == 0) {
        BX_ERROR(("VMFAIL: VMCS host CR4.PAE=0 with x86-64 host"));
        return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
     }
     if (! IsCanonical(host_state->rip)) {
        BX_ERROR(("VMFAIL: VMCS host RIP non-canonical"));
        return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
     }
  }
  else {
     if (GET32H(host_state->rip) != 0) {
        BX_ERROR(("VMFAIL: VMCS host RIP > 32 bit"));
        return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
     }
     if (host_state->cr4 & BX_CR4_PCIDE_MASK) {
        BX_ERROR(("VMFAIL: VMCS host CR4.PCIDE set"));
        return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
     }
  }
#endif

  return VMXERR_NO_ERROR;
}

BX_CPP_INLINE bx_bool IsLimitAccessRightsConsistent(Bit32u limit, Bit32u ar)
{
  bx_bool g = (ar >> 15) & 1;

  // access rights reserved bits set
  if (ar & 0xfffe0f00) return 0;

  if (g) {
    // if any of the bits in limit[11:00] are '0 <=> G must be '0
    if ((limit & 0xfff) != 0xfff)
       return 0;
  }
  else {
    // if any of the bits in limit[31:20] are '1 <=> G must be '1
    if ((limit & 0xfff00000) != 0)
       return 0;
  }

  return 1;
}

Bit32u BX_CPU_C::VMenterLoadCheckGuestState(Bit64u *qualification)
{
  static const char *segname[] = { "ES", "CS", "SS", "DS", "FS", "GS" };
  int n;

  VMCS_GUEST_STATE guest;
  VMCS_CACHE *vm = &BX_CPU_THIS_PTR vmcs;

  *qualification = VMENTER_ERR_NO_ERROR;

  //
  // Load and Check Guest State from VMCS
  //

  guest.rflags = VMread_natural(VMCS_GUEST_RFLAGS);
  // RFLAGS reserved bits [63:22], bit 15, bit 5, bit 3 must be zero
  if (guest.rflags & BX_CONST64(0xFFFFFFFFFFC08028)) {
     BX_ERROR(("VMENTER FAIL: RFLAGS reserved bits are set"));
     return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }
  // RFLAGS[1] must be always set
  if ((guest.rflags & 0x2) == 0) {
     BX_ERROR(("VMENTER FAIL: RFLAGS[1] cleared"));
     return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }

  bx_bool v8086_guest = 0;
  if (guest.rflags & EFlagsVMMask)
     v8086_guest = 1;

  bx_bool x86_64_guest = 0; // can't be 1 if X86_64 is not supported (checked before)
  Bit32u vmentry_ctrls = vm->vmentry_ctrls;
#if BX_SUPPORT_X86_64
  if (vmentry_ctrls & VMX_VMENTRY_CTRL1_X86_64_GUEST) {
     BX_DEBUG(("VMENTER to x86-64 guest"));
     x86_64_guest = 1;
  }
#endif

  if (x86_64_guest && v8086_guest) {
     BX_ERROR(("VMENTER FAIL: Enter to x86-64 guest with RFLAGS.VM"));
     return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }

  guest.cr0 = VMread_natural(VMCS_GUEST_CR0);

#if BX_SUPPORT_VMX >= 2
  if (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_UNRESTRICTED_GUEST) {
     if (~guest.cr0 & (VMX_MSR_CR0_FIXED0 & ~(BX_CR0_PE_MASK | BX_CR0_PG_MASK))) {
        BX_ERROR(("VMENTER FAIL: VMCS guest invalid CR0"));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
     }

     bx_bool pe = (guest.cr0 & BX_CR0_PE_MASK) != 0;
     bx_bool pg = (guest.cr0 & BX_CR0_PG_MASK) != 0;
     if (pg && !pe) {
        BX_ERROR(("VMENTER FAIL: VMCS unrestricted guest CR0.PG without CR0.PE"));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
     }
  }
  else
#endif
  {
     if (~guest.cr0 & VMX_MSR_CR0_FIXED0) {
        BX_ERROR(("VMENTER FAIL: VMCS guest invalid CR0"));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
     }
  }

  if (guest.cr0 & ~VMX_MSR_CR0_FIXED1) {
     BX_ERROR(("VMENTER FAIL: VMCS guest invalid CR0"));
     return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }

#if BX_SUPPORT_VMX >= 2
  bx_bool real_mode_guest = 0;
  if (! (guest.cr0 & BX_CR0_PE_MASK))
     real_mode_guest = 1;
#endif

  guest.cr3 = VMread_natural(VMCS_GUEST_CR3);
#if BX_SUPPORT_X86_64
  if (! IsValidPhyAddr(guest.cr3)) {
     BX_ERROR(("VMENTER FAIL: VMCS guest invalid CR3"));
     return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }
#endif

  guest.cr4 = VMread_natural(VMCS_GUEST_CR4);
  if (~guest.cr4 & VMX_MSR_CR4_FIXED0) {
     BX_ERROR(("VMENTER FAIL: VMCS guest invalid CR4"));
     return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
  }

  if (guest.cr4 & ~VMX_MSR_CR4_FIXED1) {
     BX_ERROR(("VMENTER FAIL: VMCS guest invalid CR4"));
     return VMXERR_VMENTRY_INVALID_VM_HOST_STATE_FIELD;
  }

#if BX_SUPPORT_X86_64
  if (x86_64_guest) {
     if ((guest.cr4 & BX_CR4_PAE_MASK) == 0) {
        BX_ERROR(("VMENTER FAIL: VMCS guest CR4.PAE=0 in x86-64 mode"));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
     }
  }
  else {
     if (guest.cr4 & BX_CR4_PCIDE_MASK) {
        BX_ERROR(("VMENTER FAIL: VMCS CR4.PCIDE set in 32-bit guest"));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
     }
  }
#endif

#if BX_SUPPORT_X86_64
  if (vmentry_ctrls & VMX_VMENTRY_CTRL1_LOAD_DBG_CTRLS) {
     guest.dr7 = VMread_natural(VMCS_GUEST_DR7);
     if (GET32H(guest.dr7)) {
        BX_ERROR(("VMENTER FAIL: VMCS guest invalid DR7"));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
     }
  }
#endif

  //
  // Load and Check Guest State from VMCS - Segment Registers
  //

  for (n=0; n<6; n++) {
     Bit16u selector = VMread16(VMCS_16BIT_GUEST_ES_SELECTOR + 2*n);
     bx_address base = (bx_address) VMread_natural(VMCS_GUEST_ES_BASE + 2*n);
     Bit32u limit = VMread32(VMCS_32BIT_GUEST_ES_LIMIT + 2*n);
     Bit32u ar = VMread32(VMCS_32BIT_GUEST_ES_ACCESS_RIGHTS + 2*n);
     ar = vmx_from_ar_byte_rd(ar);
     bx_bool invalid = (ar >> 16) & 1;

     set_segment_ar_data(&guest.sregs[n], !invalid,
                  (Bit16u) selector, base, limit, (Bit16u) ar);

     if (v8086_guest) {
        // guest in V8086 mode
        if (base != ((bx_address)(selector << 4))) {
          BX_ERROR(("VMENTER FAIL: VMCS v8086 guest bad %s.BASE", segname[n]));
          return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
        }
        if (limit != 0xffff) {
          BX_ERROR(("VMENTER FAIL: VMCS v8086 guest %s.LIMIT != 0xFFFF", segname[n]));
          return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
        }
        // present, expand-up read/write accessed, segment, DPL=3
        if (ar != 0xF3) {
          BX_ERROR(("VMENTER FAIL: VMCS v8086 guest %s.AR != 0xF3", segname[n]));
          return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
        }

        continue; // go to next segment register
     }

#if BX_SUPPORT_X86_64
     if (n >= BX_SEG_REG_FS) {
        if (! IsCanonical(base)) {
          BX_ERROR(("VMENTER FAIL: VMCS guest %s.BASE non canonical", segname[n]));
          return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
        }
     }
#endif

     if (n != BX_SEG_REG_CS && invalid)
        continue;

#if BX_SUPPORT_X86_64
     if (n == BX_SEG_REG_SS && (selector & BX_SELECTOR_RPL_MASK) == 0) {
        // SS is allowed to be NULL selector if going to 64-bit guest
        if (x86_64_guest && guest.sregs[BX_SEG_REG_CS].cache.u.segment.l)
           continue;
     }

     if (n < BX_SEG_REG_FS) {
        if (GET32H(base) != 0) {
          BX_ERROR(("VMENTER FAIL: VMCS guest %s.BASE > 32 bit", segname[n]));
          return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
        }
     }
#endif

     if (! guest.sregs[n].cache.segment) {
        BX_ERROR(("VMENTER FAIL: VMCS guest %s not segment", segname[n]));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
     }

     if (! guest.sregs[n].cache.p) {
        BX_ERROR(("VMENTER FAIL: VMCS guest %s not present", segname[n]));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
     }

     if (! IsLimitAccessRightsConsistent(limit, ar)) {
        BX_ERROR(("VMENTER FAIL: VMCS guest %s.AR/LIMIT malformed", segname[n]));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
     }

     if (n == BX_SEG_REG_CS) {
        // CS checks
        switch (guest.sregs[BX_SEG_REG_CS].cache.type) {
          case BX_CODE_EXEC_ONLY_ACCESSED:
          case BX_CODE_EXEC_READ_ACCESSED:
             // non-conforming segment
             if (guest.sregs[BX_SEG_REG_CS].selector.rpl != guest.sregs[BX_SEG_REG_CS].cache.dpl) {
               BX_ERROR(("VMENTER FAIL: VMCS guest non-conforming CS.RPL <> CS.DPL"));
               return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
             }
             break;
          case BX_CODE_EXEC_ONLY_CONFORMING_ACCESSED:
          case BX_CODE_EXEC_READ_CONFORMING_ACCESSED:
             // conforming segment
             if (guest.sregs[BX_SEG_REG_CS].selector.rpl < guest.sregs[BX_SEG_REG_CS].cache.dpl) {
               BX_ERROR(("VMENTER FAIL: VMCS guest non-conforming CS.RPL < CS.DPL"));
               return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
             }
             break;
#if BX_SUPPORT_VMX >= 2
          case BX_DATA_READ_WRITE_ACCESSED:
             if (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_UNRESTRICTED_GUEST) {
               if (guest.sregs[BX_SEG_REG_CS].cache.dpl != 0) {
                 BX_ERROR(("VMENTER FAIL: VMCS unrestricted guest CS.DPL != 0"));
                 return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
               }
               break;
             }
             // fall through
#endif
          default:
             BX_ERROR(("VMENTER FAIL: VMCS guest CS.TYPE"));
             return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
        }

#if BX_SUPPORT_X86_64
        if (x86_64_guest) {
          if (guest.sregs[BX_SEG_REG_CS].cache.u.segment.d_b && guest.sregs[BX_SEG_REG_CS].cache.u.segment.l) {
             BX_ERROR(("VMENTER FAIL: VMCS x86_64 guest wrong CS.D_B/L"));
             return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
          }
        }
#endif
     }
     else if (n == BX_SEG_REG_SS) {
        // SS checks
        switch (guest.sregs[BX_SEG_REG_SS].cache.type) {
          case BX_DATA_READ_WRITE_ACCESSED:
          case BX_DATA_READ_WRITE_EXPAND_DOWN_ACCESSED:
             break;
          default:
             BX_ERROR(("VMENTER FAIL: VMCS guest SS.TYPE"));
             return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
        }
     }
     else {
        // DS, ES, FS, GS
        if ((guest.sregs[n].cache.type & 0x1) == 0) {
           BX_ERROR(("VMENTER FAIL: VMCS guest %s not ACCESSED", segname[n]));
           return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
        }

        if (guest.sregs[n].cache.type & 0x8) {
           if ((guest.sregs[n].cache.type & 0x2) == 0) {
              BX_ERROR(("VMENTER FAIL: VMCS guest CODE segment %s not READABLE", segname[n]));
              return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
           }
        }

        if (! (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_UNRESTRICTED_GUEST)) {
           if (guest.sregs[n].cache.type < 11) {
              // data segment or non-conforming code segment
              if (guest.sregs[n].selector.rpl > guest.sregs[n].cache.dpl) {
                BX_ERROR(("VMENTER FAIL: VMCS guest non-conforming %s.RPL < %s.DPL", segname[n], segname[n]));
                return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
              }
           }
        }
     }
  }

  if (! v8086_guest) {
     if (! (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_UNRESTRICTED_GUEST)) {
        if (guest.sregs[BX_SEG_REG_SS].selector.rpl != guest.sregs[BX_SEG_REG_CS].selector.rpl) {
           BX_ERROR(("VMENTER FAIL: VMCS guest CS.RPL != SS.RPL"));
           return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
        }
        if (guest.sregs[BX_SEG_REG_SS].selector.rpl != guest.sregs[BX_SEG_REG_SS].cache.dpl) {
           BX_ERROR(("VMENTER FAIL: VMCS guest SS.RPL <> SS.DPL"));
           return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
        }
     }
#if BX_SUPPORT_VMX >= 2
     else { // unrestricted guest
        if (real_mode_guest || guest.sregs[BX_SEG_REG_CS].cache.type == BX_DATA_READ_WRITE_ACCESSED) {
           if (guest.sregs[BX_SEG_REG_SS].cache.dpl != 0) {
             BX_ERROR(("VMENTER FAIL: VMCS unrestricted guest SS.DPL != 0"));
             return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
           }
        }
     }
#endif
  }

  //
  // Load and Check Guest State from VMCS - GDTR/IDTR
  //

  Bit64u gdtr_base = VMread_natural(VMCS_GUEST_GDTR_BASE);
  Bit32u gdtr_limit = VMread32(VMCS_32BIT_GUEST_GDTR_LIMIT);
  Bit64u idtr_base = VMread_natural(VMCS_GUEST_IDTR_BASE);
  Bit32u idtr_limit = VMread32(VMCS_32BIT_GUEST_IDTR_LIMIT);

#if BX_SUPPORT_X86_64
  if (! IsCanonical(gdtr_base) || ! IsCanonical(idtr_base)) {
    BX_ERROR(("VMENTER FAIL: VMCS guest IDTR/IDTR.BASE non canonical"));
    return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }
#endif
  if (gdtr_limit > 0xffff || idtr_limit > 0xffff) {
     BX_ERROR(("VMENTER FAIL: VMCS guest GDTR/IDTR limit > 0xFFFF"));
     return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }

  //
  // Load and Check Guest State from VMCS - LDTR
  //

  Bit16u ldtr_selector = VMread16(VMCS_16BIT_GUEST_LDTR_SELECTOR);
  Bit64u ldtr_base = VMread_natural(VMCS_GUEST_LDTR_BASE);
  Bit32u ldtr_limit = VMread32(VMCS_32BIT_GUEST_LDTR_LIMIT);
  Bit32u ldtr_ar = VMread32(VMCS_32BIT_GUEST_LDTR_ACCESS_RIGHTS);
  ldtr_ar = vmx_from_ar_byte_rd(ldtr_ar);
  bx_bool ldtr_invalid = (ldtr_ar >> 16) & 1;
  if (set_segment_ar_data(&guest.ldtr, !ldtr_invalid, 
         (Bit16u) ldtr_selector, ldtr_base, ldtr_limit, (Bit16u)(ldtr_ar)))
  {
     // ldtr is valid
     if (guest.ldtr.selector.ti) {
        BX_ERROR(("VMENTER FAIL: VMCS guest LDTR.TI set"));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
     }
     if (guest.ldtr.cache.type != BX_SYS_SEGMENT_LDT) {
        BX_ERROR(("VMENTER FAIL: VMCS guest incorrect LDTR type (%d)", guest.ldtr.cache.type));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
     }
     if (guest.ldtr.cache.segment) {
        BX_ERROR(("VMENTER FAIL: VMCS guest LDTR is not system segment"));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
     }
     if (! guest.ldtr.cache.p) {
        BX_ERROR(("VMENTER FAIL: VMCS guest LDTR not present"));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
     }
     if (! IsLimitAccessRightsConsistent(ldtr_limit, ldtr_ar)) {
        BX_ERROR(("VMENTER FAIL: VMCS guest LDTR.AR/LIMIT malformed"));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
     }
#if BX_SUPPORT_X86_64
     if (! IsCanonical(ldtr_base)) {
        BX_ERROR(("VMENTER FAIL: VMCS guest LDTR.BASE non canonical"));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
     }
#endif
  }

  //
  // Load and Check Guest State from VMCS - TR
  //

  Bit16u tr_selector = VMread16(VMCS_16BIT_GUEST_TR_SELECTOR);
  Bit64u tr_base = VMread_natural(VMCS_GUEST_TR_BASE);
  Bit32u tr_limit = VMread32(VMCS_32BIT_GUEST_TR_LIMIT);
  Bit32u tr_ar = VMread32(VMCS_32BIT_GUEST_TR_ACCESS_RIGHTS);
  tr_ar = vmx_from_ar_byte_rd(tr_ar);
  bx_bool tr_invalid = (tr_ar >> 16) & 1;

#if BX_SUPPORT_X86_64
  if (! IsCanonical(tr_base)) {
    BX_ERROR(("VMENTER FAIL: VMCS guest TR.BASE non canonical"));
    return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }
#endif

  set_segment_ar_data(&guest.tr, !tr_invalid, 
      (Bit16u) tr_selector, tr_base, tr_limit, (Bit16u)(tr_ar));

  if (tr_invalid) {
     BX_ERROR(("VMENTER FAIL: VMCS guest TR invalid"));
     return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }
  if (guest.tr.selector.ti) {
     BX_ERROR(("VMENTER FAIL: VMCS guest TR.TI set"));
     return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }
  if (guest.tr.cache.segment) {
     BX_ERROR(("VMENTER FAIL: VMCS guest TR is not system segment"));
     return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }
  if (! guest.tr.cache.p) {
     BX_ERROR(("VMENTER FAIL: VMCS guest TR not present"));
     return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }
  if (! IsLimitAccessRightsConsistent(tr_limit, tr_ar)) {
     BX_ERROR(("VMENTER FAIL: VMCS guest TR.AR/LIMIT malformed"));
     return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }

  switch(guest.tr.cache.type) {
    case BX_SYS_SEGMENT_BUSY_386_TSS:
      break;
    case BX_SYS_SEGMENT_BUSY_286_TSS:
      if (! x86_64_guest) break;
      // fall through
    default:
      BX_ERROR(("VMENTER FAIL: VMCS guest incorrect TR type"));
      return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }

  //
  // Load and Check Guest State from VMCS - MSRS
  //

  guest.ia32_debugctl_msr = VMread64(VMCS_64BIT_GUEST_IA32_DEBUGCTL);
  guest.smbase = VMread32(VMCS_32BIT_GUEST_SMBASE);

  guest.sysenter_esp_msr = VMread_natural(VMCS_GUEST_IA32_SYSENTER_ESP_MSR);
  guest.sysenter_eip_msr = VMread_natural(VMCS_GUEST_IA32_SYSENTER_EIP_MSR);
  guest.sysenter_cs_msr = VMread32(VMCS_32BIT_GUEST_IA32_SYSENTER_CS_MSR);

#if BX_SUPPORT_X86_64
  if (! IsCanonical(guest.sysenter_esp_msr)) {
    BX_ERROR(("VMENTER FAIL: VMCS guest SYSENTER_ESP_MSR non canonical"));
    return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }
  if (! IsCanonical(guest.sysenter_eip_msr)) {
    BX_ERROR(("VMENTER FAIL: VMCS guest SYSENTER_EIP_MSR non canonical"));
    return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }
#endif

#if BX_SUPPORT_VMX >= 2
  if (vmentry_ctrls & VMX_VMENTRY_CTRL1_LOAD_PAT_MSR) {
    guest.pat_msr = VMread64(VMCS_64BIT_GUEST_IA32_PAT);
    if (! isValidMSR_PAT(guest.pat_msr)) {
      BX_ERROR(("VMENTER FAIL: invalid Memory Type in guest MSR_PAT"));
      return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
    }
  }
#endif

  guest.rip = VMread_natural(VMCS_GUEST_RIP);
  guest.rsp = VMread_natural(VMCS_GUEST_RSP);

#if BX_SUPPORT_VMX >= 2 && BX_SUPPORT_X86_64
  if (vmentry_ctrls & VMX_VMENTRY_CTRL1_LOAD_EFER_MSR) {
    guest.efer_msr = VMread64(VMCS_64BIT_GUEST_IA32_EFER);
    if (guest.efer_msr & ~((Bit64u) BX_CPU_THIS_PTR efer_suppmask)) {
      BX_ERROR(("VMENTER FAIL: VMCS guest EFER reserved bits set !"));
      return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
    }
    bx_bool lme = (guest.efer_msr >>  8) & 0x1;
    bx_bool lma = (guest.efer_msr >> 10) & 0x1;
    if (lma != x86_64_guest) {
      BX_ERROR(("VMENTER FAIL: VMCS guest EFER.LMA doesn't match x86_64_guest !"));
      return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
    }
    if (lma != lme && (guest.cr0 & BX_CR0_PG_MASK) != 0) {
      BX_ERROR(("VMENTER FAIL: VMCS guest EFER (0x%08x) inconsistent value !", (Bit32u) guest.efer_msr));
      return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
    }
  }

  if (! x86_64_guest || !guest.sregs[BX_SEG_REG_CS].cache.u.segment.l) {
    if (GET32H(guest.rip) != 0) {
       BX_ERROR(("VMENTER FAIL: VMCS guest RIP > 32 bit"));
       return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
    }
  }
#endif

  //
  // Load and Check Guest Non-Registers State from VMCS
  //

  vm->vmcs_linkptr = VMread64(VMCS_64BIT_GUEST_LINK_POINTER);
  if (vm->vmcs_linkptr != BX_INVALID_VMCSPTR) {
    if (! IsValidPageAlignedPhyAddr(vm->vmcs_linkptr)) {
      *qualification = (Bit64u) VMENTER_ERR_GUEST_STATE_LINK_POINTER;
      BX_ERROR(("VMFAIL: VMCS link pointer malformed"));
      return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
    }

    Bit32u revision = VMXReadRevisionID((bx_phy_address) vm->vmcs_linkptr);
    if (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_VMCS_SHADOWING) {
      if ((revision & BX_VMCS_SHADOW_BIT_MASK) == 0) {
        *qualification = (Bit64u) VMENTER_ERR_GUEST_STATE_LINK_POINTER;
        BX_ERROR(("VMFAIL: VMCS link pointer must indicate shadow VMCS revision ID = %d", revision));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
      }
      revision &= ~BX_VMCS_SHADOW_BIT_MASK;
    }
    if (revision != VMX_VMCS_REVISION_ID) {
      *qualification = (Bit64u) VMENTER_ERR_GUEST_STATE_LINK_POINTER;
      BX_ERROR(("VMFAIL: VMCS link pointer incorrect revision ID %d != %d", revision, VMX_VMCS_REVISION_ID));
      return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
    }

    if (! BX_CPU_THIS_PTR in_smm || (vmentry_ctrls & VMX_VMENTRY_CTRL1_SMM_ENTER) != 0) {
      if (vm->vmcs_linkptr == BX_CPU_THIS_PTR vmcsptr) {
        *qualification = (Bit64u) VMENTER_ERR_GUEST_STATE_LINK_POINTER;
        BX_ERROR(("VMFAIL: VMCS link pointer equal to current VMCS pointer"));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
      }
    }
    else {
      if (vm->vmcs_linkptr == BX_CPU_THIS_PTR vmxonptr) {
        *qualification = (Bit64u) VMENTER_ERR_GUEST_STATE_LINK_POINTER;
        BX_ERROR(("VMFAIL: VMCS link pointer equal to VMXON pointer"));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
      }
    }
  }

  guest.tmpDR6 = (Bit32u) VMread_natural(VMCS_GUEST_PENDING_DBG_EXCEPTIONS);
  if (guest.tmpDR6 & BX_CONST64(0xFFFFFFFFFFFFAFF0)) {
    BX_ERROR(("VMENTER FAIL: VMCS guest tmpDR6 reserved bits"));
    return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }

  guest.activity_state = VMread32(VMCS_32BIT_GUEST_ACTIVITY_STATE);
  if (guest.activity_state >= BX_VMX_LAST_ACTIVITY_STATE) {
    BX_ERROR(("VMENTER FAIL: VMCS guest activity state %d", guest.activity_state));
    return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }

  if (guest.activity_state == BX_ACTIVITY_STATE_HLT) {
    if (guest.sregs[BX_SEG_REG_SS].cache.dpl != 0) {
      BX_ERROR(("VMENTER FAIL: VMCS guest HLT state with SS.DPL=%d", guest.sregs[BX_SEG_REG_SS].cache.dpl));
      return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
    }
  }

  guest.interruptibility_state = VMread32(VMCS_32BIT_GUEST_INTERRUPTIBILITY_STATE);
  if (guest.interruptibility_state & ~BX_VMX_INTERRUPTIBILITY_STATE_MASK) {
    BX_ERROR(("VMENTER FAIL: VMCS guest interruptibility state broken"));
    return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }

  if (guest.interruptibility_state & 0x3) {
    if (guest.activity_state != BX_ACTIVITY_STATE_ACTIVE) {
      BX_ERROR(("VMENTER FAIL: VMCS guest interruptibility state broken when entering non active CPU state %d", guest.activity_state));
      return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
    }
  }

  if ((guest.interruptibility_state & BX_VMX_INTERRUPTS_BLOCKED_BY_STI) &&
      (guest.interruptibility_state & BX_VMX_INTERRUPTS_BLOCKED_BY_MOV_SS))
  {
    BX_ERROR(("VMENTER FAIL: VMCS guest interruptibility state broken"));
    return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
  }

  if ((guest.rflags & EFlagsIFMask) == 0) {
    if (guest.interruptibility_state & BX_VMX_INTERRUPTS_BLOCKED_BY_STI) {
      BX_ERROR(("VMENTER FAIL: VMCS guest interrupts can't be blocked by STI when EFLAGS.IF = 0"));
      return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
    }
  }

  if (VMENTRY_INJECTING_EVENT(vm->vmentry_interr_info)) {
    unsigned event_type = (vm->vmentry_interr_info >> 8) & 7;
    if (event_type == BX_EXTERNAL_INTERRUPT) {
      if ((guest.interruptibility_state & 0x3) != 0 || (guest.rflags & EFlagsIFMask) == 0) {
        BX_ERROR(("VMENTER FAIL: VMCS guest interrupts blocked when injecting external interrupt"));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
      }
    }
    if (event_type == BX_NMI) {
      if ((guest.interruptibility_state & 0x3) != 0) {
        BX_ERROR(("VMENTER FAIL: VMCS guest interrupts blocked when injecting NMI"));
        return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
      }
    }
  }

  if (vmentry_ctrls & VMX_VMENTRY_CTRL1_SMM_ENTER) {
    if (! (guest.interruptibility_state & BX_VMX_INTERRUPTS_BLOCKED_SMI_BLOCKED)) {
      BX_ERROR(("VMENTER FAIL: VMCS SMM guest should block SMI"));
      return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
    }

    if (guest.activity_state == BX_ACTIVITY_STATE_WAIT_FOR_SIPI) {
      BX_ERROR(("VMENTER FAIL: The activity state must not indicate the wait-for-SIPI state if entering to SMM guest"));
      return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
    }
  }

  if (guest.interruptibility_state & BX_VMX_INTERRUPTS_BLOCKED_SMI_BLOCKED) {
    if (! BX_CPU_THIS_PTR in_smm) {
      BX_ERROR(("VMENTER FAIL: VMCS SMI blocked when not in SMM mode"));
      return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
    }
  }

  if (! x86_64_guest && (guest.cr4 & BX_CR4_PAE_MASK) != 0 && (guest.cr0 & BX_CR0_PG_MASK) != 0) {
#if BX_SUPPORT_VMX >= 2
    if (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_EPT_ENABLE) {
      for (n=0;n<4;n++)
         guest.pdptr[n] = VMread64(VMCS_64BIT_GUEST_IA32_PDPTE0 + 2*n);

      if (! CheckPDPTR(guest.pdptr)) {
         *qualification = VMENTER_ERR_GUEST_STATE_PDPTR_LOADING;
         BX_ERROR(("VMENTER: EPT Guest State PDPTRs Checks Failed"));
         return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
      }
    }
    else
#endif
    {
      if (! CheckPDPTR(guest.cr3)) {
         *qualification = VMENTER_ERR_GUEST_STATE_PDPTR_LOADING;
         BX_ERROR(("VMENTER: Guest State PDPTRs Checks Failed"));
         return VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE;
      }
    }
  }

  //
  // Load Guest State -> VMENTER
  //

#if BX_SUPPORT_X86_64
#if BX_SUPPORT_VMX >= 2
  // modify EFER.LMA / EFER.LME before setting CR4

  // It is recommended that 64-bit VMM software use the 1-settings of the "load IA32_EFER"
  // VM entry control and the "save IA32_EFER" VM-exit control. If VMentry is establishing
  // CR0.PG=0 and if the "IA-32e mode guest" and "load IA32_EFER" VM entry controls are
  // both 0, VM entry leaves IA32_EFER.LME unmodified (i.e., the host value will persist
  // in the guest) -- Quote from Intel SDM
  if (vmentry_ctrls & VMX_VMENTRY_CTRL1_LOAD_EFER_MSR) {
     BX_CPU_THIS_PTR efer.set32((Bit32u) guest.efer_msr);
  }
  else
#endif
  {
    if (x86_64_guest) {
      BX_CPU_THIS_PTR efer.set32(BX_CPU_THIS_PTR efer.get32() | (BX_EFER_LME_MASK | BX_EFER_LMA_MASK));
    }
    else {
      // when loading unrestricted guest with CR0.PG=0 EFER.LME is unmodified
      // (i.e., the host value will persist in the guest)
      if (guest.cr0 & BX_CR0_PG_MASK)
        BX_CPU_THIS_PTR efer.set32(BX_CPU_THIS_PTR efer.get32() & ~(BX_EFER_LME_MASK | BX_EFER_LMA_MASK));
      else
        BX_CPU_THIS_PTR efer.set32(BX_CPU_THIS_PTR efer.get32() &  ~BX_EFER_LMA_MASK);
    }
  }
#endif

// keep bits ET(4), reserved bits 15:6, 17, 28:19, NW(29), CD(30)
#define VMX_KEEP_CR0_BITS 0x7FFAFFD0

  guest.cr0 = (BX_CPU_THIS_PTR cr0.get32() & VMX_KEEP_CR0_BITS) | (guest.cr0 & ~VMX_KEEP_CR0_BITS);

  if (! check_CR0(guest.cr0)) {
    BX_PANIC(("VMENTER CR0 is broken !"));
  }
  if (! check_CR4(guest.cr4)) {
    BX_PANIC(("VMENTER CR4 is broken !"));
  }

  BX_CPU_THIS_PTR cr0.set32((Bit32u) guest.cr0);
  BX_CPU_THIS_PTR cr4.set32((Bit32u) guest.cr4);
  BX_CPU_THIS_PTR cr3 = guest.cr3;

#if BX_SUPPORT_VMX >= 2
  if (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_EPT_ENABLE) {
    // load PDPTR only in PAE legacy mode
    if (BX_CPU_THIS_PTR cr0.get_PG() && BX_CPU_THIS_PTR cr4.get_PAE() && !x86_64_guest) {
      for (n = 0; n < 4; n++)
        BX_CPU_THIS_PTR PDPTR_CACHE.entry[n] = guest.pdptr[n];
    }
  }
#endif

  if (vmentry_ctrls & VMX_VMENTRY_CTRL1_LOAD_DBG_CTRLS) {
    // always clear bits 15:14 and set bit 10
    BX_CPU_THIS_PTR dr7.set32((guest.dr7 & ~0xc000) | 0x400);
  }

  RIP = BX_CPU_THIS_PTR prev_rip = guest.rip;
  RSP = guest.rsp;

  BX_CPU_THIS_PTR async_event = 0;

  setEFlags((Bit32u) guest.rflags);

#ifdef BX_SUPPORT_CS_LIMIT_DEMOTION
  // Handle special case of CS.LIMIT demotion (new descriptor limit is
  // smaller than current one)
  if (BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.limit_scaled > guest.sregs[BX_SEG_REG_CS].cache.u.segment.limit_scaled)
    BX_CPU_THIS_PTR iCache.flushICacheEntries();
#endif
  
  for(unsigned segreg=0; segreg<6; segreg++)
    BX_CPU_THIS_PTR sregs[segreg] = guest.sregs[segreg];

  BX_CPU_THIS_PTR gdtr.base = gdtr_base;
  BX_CPU_THIS_PTR gdtr.limit = gdtr_limit;
  BX_CPU_THIS_PTR idtr.base = idtr_base;
  BX_CPU_THIS_PTR idtr.limit = idtr_limit;

  BX_CPU_THIS_PTR ldtr = guest.ldtr;
  BX_CPU_THIS_PTR tr = guest.tr;

  BX_CPU_THIS_PTR msr.sysenter_esp_msr = guest.sysenter_esp_msr;
  BX_CPU_THIS_PTR msr.sysenter_eip_msr = guest.sysenter_eip_msr;
  BX_CPU_THIS_PTR msr.sysenter_cs_msr  = guest.sysenter_cs_msr;

#if BX_SUPPORT_VMX >= 2
  if (vmentry_ctrls & VMX_VMENTRY_CTRL1_LOAD_PAT_MSR) {
    BX_CPU_THIS_PTR msr.pat = guest.pat_msr;
  }
  vm->ple.last_pause_time = vm->ple.first_pause_time = 0;
#endif

  //
  // Load Guest Non-Registers State -> VMENTER
  //

  if (vm->vmentry_ctrls & VMX_VMENTRY_CTRL1_SMM_ENTER)
    BX_PANIC(("VMENTER: entry to SMM is not implemented yet !"));

  if (VMENTRY_INJECTING_EVENT(vm->vmentry_interr_info)) {
    // the VMENTRY injecting event to the guest
    BX_CPU_THIS_PTR inhibit_mask = 0; // do not block interrupts
    BX_CPU_THIS_PTR debug_trap = 0;
    guest.activity_state = BX_ACTIVITY_STATE_ACTIVE;
  }
  else {
    if (guest.tmpDR6 & (1 << 12))
      BX_CPU_THIS_PTR debug_trap = guest.tmpDR6 & 0x0000400F;
    else
      BX_CPU_THIS_PTR debug_trap = guest.tmpDR6 & 0x00004000;
    if (BX_CPU_THIS_PTR debug_trap) {
      BX_CPU_THIS_PTR debug_trap |= BX_DEBUG_TRAP_HIT;
      BX_CPU_THIS_PTR async_event = 1;
    }

    if (guest.interruptibility_state & BX_VMX_INTERRUPTS_BLOCKED_BY_STI)
      inhibit_interrupts(BX_INHIBIT_INTERRUPTS);
    else if (guest.interruptibility_state & BX_VMX_INTERRUPTS_BLOCKED_BY_MOV_SS)
      inhibit_interrupts(BX_INHIBIT_INTERRUPTS_BY_MOVSS);
    else
      BX_CPU_THIS_PTR inhibit_mask = 0;
  }

  if (guest.interruptibility_state & BX_VMX_INTERRUPTS_BLOCKED_NMI_BLOCKED) {
    if (vm->vmexec_ctrls1 & VMX_VM_EXEC_CTRL1_VIRTUAL_NMI)
      mask_event(BX_EVENT_VMX_VIRTUAL_NMI);
    else
      mask_event(BX_EVENT_NMI);
  }

  if (vm->vmexec_ctrls2 & VMX_VM_EXEC_CTRL2_NMI_WINDOW_EXITING)
    signal_event(BX_EVENT_VMX_VIRTUAL_NMI);

  if (vm->vmexec_ctrls2 & VMX_VM_EXEC_CTRL2_INTERRUPT_WINDOW_VMEXIT)
    signal_event(BX_EVENT_VMX_INTERRUPT_WINDOW_EXITING);

  handleCpuContextChange();

#if BX_SUPPORT_MONITOR_MWAIT
  BX_CPU_THIS_PTR monitor.reset_monitor();
#endif

  BX_INSTR_TLB_CNTRL(BX_CPU_ID, BX_INSTR_CONTEXT_SWITCH, 0);

  if (guest.activity_state) {
    BX_DEBUG(("VMEntry to non-active CPU state %d", guest.activity_state));
    enter_sleep_state(guest.activity_state);
  }

  return VMXERR_NO_ERROR;
}

void BX_CPU_C::VMenterInjectEvents(void)
{
  VMCS_CACHE *vm = &BX_CPU_THIS_PTR vmcs;

  if (! VMENTRY_INJECTING_EVENT(vm->vmentry_interr_info))
     return;

  /* the VMENTRY injecting event to the guest */
  unsigned vector = vm->vmentry_interr_info & 0xff;
  unsigned type = (vm->vmentry_interr_info >> 8) & 7;
  unsigned push_error = vm->vmentry_interr_info & (1 << 11);
  unsigned error_code = push_error ? vm->vmentry_excep_err_code : 0;

  if (type == 7) {
    if (BX_SUPPORT_VMX_EXTENSION(BX_VMX_MONITOR_TRAP_FLAG)) {
      signal_event(BX_EVENT_VMX_MONITOR_TRAP_FLAG);
      return;
    }
  }

  bx_bool is_INT = 0;
  switch(type) {
    case BX_EXTERNAL_INTERRUPT:
    case BX_HARDWARE_EXCEPTION:
      BX_CPU_THIS_PTR EXT = 1;
      break;

    case BX_NMI:
      if (vm->vmexec_ctrls1 & VMX_VM_EXEC_CTRL1_VIRTUAL_NMI)
        mask_event(BX_EVENT_VMX_VIRTUAL_NMI);
      else
        mask_event(BX_EVENT_NMI);

      BX_CPU_THIS_PTR EXT = 1;
      break;

    case BX_PRIVILEGED_SOFTWARE_INTERRUPT:
      BX_CPU_THIS_PTR EXT = 1;
      is_INT = 1;
      break;

    case BX_SOFTWARE_INTERRUPT:
    case BX_SOFTWARE_EXCEPTION:
      is_INT = 1;
      break;

    default:
      BX_PANIC(("VMENTER: unsupported event injection type %d !", type));
  }

  // keep prev_rip value/unwind in case of event delivery failure
  if (is_INT)
    RIP += vm->vmentry_instr_length;

  BX_DEBUG(("VMENTER: Injecting vector 0x%02x (error_code 0x%04x)", vector, error_code));

  if (type == BX_HARDWARE_EXCEPTION) {
    // record exception the same way as BX_CPU_C::exception does
    BX_ASSERT(vector < BX_CPU_HANDLED_EXCEPTIONS);
    BX_CPU_THIS_PTR last_exception_type = exceptions_info[vector].exception_type;
  }

  vm->idt_vector_info = vm->vmentry_interr_info & ~0x80000000;
  vm->idt_vector_error_code = error_code;

  interrupt(vector, type, push_error, error_code);

  BX_CPU_THIS_PTR last_exception_type = 0; // error resolved
}

Bit32u BX_CPU_C::LoadMSRs(Bit32u msr_cnt, bx_phy_address pAddr)
{
  Bit64u msr_lo, msr_hi;

  for (Bit32u msr = 1; msr <= msr_cnt; msr++) {
    access_read_physical(pAddr,     8, &msr_lo);
    BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr, 8, BX_READ, BX_VMX_LOAD_MSR_ACCESS, (Bit8u*)(&msr_lo));
    access_read_physical(pAddr + 8, 8, &msr_hi);
    BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr + 8, 8, BX_READ, BX_VMX_LOAD_MSR_ACCESS, (Bit8u*)(&msr_hi));

    if (GET32H(msr_lo))
      return msr;

    Bit32u index = GET32L(msr_lo);

#if BX_SUPPORT_X86_64
    if (index == BX_MSR_FSBASE || index == BX_MSR_GSBASE)
      return msr;
#endif

    if (bx_cpuid_support_x2apic()) {
      if ((index & 0xfffff800) == 0x800) // X2APIC range
        return msr;
    }

    if (! wrmsr(index, msr_hi))
      return msr;

    pAddr += 16; // to next MSR
  }

  return 0;
}

Bit32u BX_CPU_C::StoreMSRs(Bit32u msr_cnt, bx_phy_address pAddr)
{
  Bit64u msr_lo, msr_hi;

  for (Bit32u msr = 1; msr <= msr_cnt; msr++) {
    access_read_physical(pAddr, 8, &msr_lo);
    BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr, 8, BX_READ, BX_VMX_STORE_MSR_ACCESS, (Bit8u*)(&msr_lo));

    if (GET32H(msr_lo))
      return msr;

    Bit32u index = GET32L(msr_lo);

    if (bx_cpuid_support_x2apic()) {
      if ((index & 0xfffff800) == 0x800) // X2APIC range
        return msr;
    }

    if (! rdmsr(index, &msr_hi))
      return msr;

    access_write_physical(pAddr + 8, 8, &msr_hi);
    BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr + 8, 8, BX_WRITE, BX_VMX_STORE_MSR_ACCESS, (Bit8u*)(&msr_hi));

    pAddr += 16; // to next MSR
  }

  return 0;
}

////////////////////////////////////////////////////////////
// VMexit
////////////////////////////////////////////////////////////

void BX_CPU_C::VMexitSaveGuestState(void)
{
  VMCS_CACHE *vm = &BX_CPU_THIS_PTR vmcs;
  int n;

  VMwrite_natural(VMCS_GUEST_CR0, BX_CPU_THIS_PTR cr0.get32());
  VMwrite_natural(VMCS_GUEST_CR3, BX_CPU_THIS_PTR cr3);
  VMwrite_natural(VMCS_GUEST_CR4, BX_CPU_THIS_PTR cr4.get32());

#if BX_SUPPORT_VMX >= 2
  if (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_EPT_ENABLE) {
    // save only if guest running in legacy PAE mode
    if (BX_CPU_THIS_PTR cr0.get_PG() && BX_CPU_THIS_PTR cr4.get_PAE() && !long_mode()) {
      for(n=0; n<4; n++) {
        VMwrite64(VMCS_64BIT_GUEST_IA32_PDPTE0 + 2*n, BX_CPU_THIS_PTR PDPTR_CACHE.entry[n]);
      }
    }
  }
#endif

  if (vm->vmexit_ctrls & VMX_VMEXIT_CTRL1_SAVE_DBG_CTRLS)
     VMwrite_natural(VMCS_GUEST_DR7, BX_CPU_THIS_PTR dr7.get32());

  VMwrite_natural(VMCS_GUEST_RIP, RIP);
  VMwrite_natural(VMCS_GUEST_RSP, RSP);
  VMwrite_natural(VMCS_GUEST_RFLAGS, read_eflags());

  for (n=0; n<6; n++) {
     Bit32u selector = BX_CPU_THIS_PTR sregs[n].selector.value;
     bx_bool invalid = !BX_CPU_THIS_PTR sregs[n].cache.valid;
     bx_address base = BX_CPU_THIS_PTR sregs[n].cache.u.segment.base;
     Bit32u limit = BX_CPU_THIS_PTR sregs[n].cache.u.segment.limit_scaled;
     Bit32u ar = (get_descriptor_h(&BX_CPU_THIS_PTR sregs[n].cache) & 0x00f0ff00) >> 8;
     ar = vmx_from_ar_byte_wr(ar | (invalid << 16));

     VMwrite16(VMCS_16BIT_GUEST_ES_SELECTOR + 2*n, selector);
     VMwrite32(VMCS_32BIT_GUEST_ES_ACCESS_RIGHTS + 2*n, ar);
     VMwrite_natural(VMCS_GUEST_ES_BASE + 2*n, base);
     VMwrite32(VMCS_32BIT_GUEST_ES_LIMIT + 2*n, limit);
  }

  // save guest LDTR
  Bit32u ldtr_selector = BX_CPU_THIS_PTR ldtr.selector.value;
  bx_bool ldtr_invalid = !BX_CPU_THIS_PTR ldtr.cache.valid;
  bx_address ldtr_base = BX_CPU_THIS_PTR ldtr.cache.u.segment.base;
  Bit32u ldtr_limit = BX_CPU_THIS_PTR ldtr.cache.u.segment.limit_scaled;
  Bit32u ldtr_ar = (get_descriptor_h(&BX_CPU_THIS_PTR ldtr.cache) & 0x00f0ff00) >> 8;
  ldtr_ar = vmx_from_ar_byte_wr(ldtr_ar | (ldtr_invalid << 16));

  VMwrite16(VMCS_16BIT_GUEST_LDTR_SELECTOR, ldtr_selector);
  VMwrite32(VMCS_32BIT_GUEST_LDTR_ACCESS_RIGHTS, ldtr_ar);
  VMwrite_natural(VMCS_GUEST_LDTR_BASE, ldtr_base);
  VMwrite32(VMCS_32BIT_GUEST_LDTR_LIMIT, ldtr_limit);

  // save guest TR
  Bit32u tr_selector = BX_CPU_THIS_PTR tr.selector.value;
  bx_bool tr_invalid = !BX_CPU_THIS_PTR tr.cache.valid;
  bx_address tr_base = BX_CPU_THIS_PTR tr.cache.u.segment.base;
  Bit32u tr_limit = BX_CPU_THIS_PTR tr.cache.u.segment.limit_scaled;
  Bit32u tr_ar = (get_descriptor_h(&BX_CPU_THIS_PTR tr.cache) & 0x00f0ff00) >> 8;
  tr_ar = vmx_from_ar_byte_wr(tr_ar | (tr_invalid << 16));

  VMwrite16(VMCS_16BIT_GUEST_TR_SELECTOR, tr_selector);
  VMwrite32(VMCS_32BIT_GUEST_TR_ACCESS_RIGHTS, tr_ar);
  VMwrite_natural(VMCS_GUEST_TR_BASE, tr_base);
  VMwrite32(VMCS_32BIT_GUEST_TR_LIMIT, tr_limit);

  VMwrite_natural(VMCS_GUEST_GDTR_BASE, BX_CPU_THIS_PTR gdtr.base);
  VMwrite32(VMCS_32BIT_GUEST_GDTR_LIMIT, BX_CPU_THIS_PTR gdtr.limit);
  VMwrite_natural(VMCS_GUEST_IDTR_BASE, BX_CPU_THIS_PTR idtr.base);
  VMwrite32(VMCS_32BIT_GUEST_IDTR_LIMIT, BX_CPU_THIS_PTR idtr.limit);

  VMwrite_natural(VMCS_GUEST_IA32_SYSENTER_ESP_MSR, BX_CPU_THIS_PTR msr.sysenter_esp_msr);
  VMwrite_natural(VMCS_GUEST_IA32_SYSENTER_EIP_MSR, BX_CPU_THIS_PTR msr.sysenter_eip_msr);
  VMwrite32(VMCS_32BIT_GUEST_IA32_SYSENTER_CS_MSR, BX_CPU_THIS_PTR msr.sysenter_cs_msr);

#if BX_SUPPORT_VMX >= 2
  if (vm->vmexit_ctrls & VMX_VMEXIT_CTRL1_STORE_PAT_MSR)
    VMwrite64(VMCS_64BIT_GUEST_IA32_PAT, BX_CPU_THIS_PTR msr.pat);
#if BX_SUPPORT_X86_64
  if (vm->vmexit_ctrls & VMX_VMEXIT_CTRL1_STORE_EFER_MSR)
    VMwrite64(VMCS_64BIT_GUEST_IA32_EFER, BX_CPU_THIS_PTR efer.get32());
#endif
#endif

  Bit32u tmpDR6 = BX_CPU_THIS_PTR debug_trap & 0x0000400f;
  if (tmpDR6 & 0xf) tmpDR6 |= (1 << 12);
  VMwrite_natural(VMCS_GUEST_PENDING_DBG_EXCEPTIONS, tmpDR6);

  // effectively wakeup from MWAIT state on VMEXIT
  if (BX_CPU_THIS_PTR activity_state >= BX_VMX_LAST_ACTIVITY_STATE)
    VMwrite32(VMCS_32BIT_GUEST_ACTIVITY_STATE, BX_ACTIVITY_STATE_ACTIVE);
  else
    VMwrite32(VMCS_32BIT_GUEST_ACTIVITY_STATE, BX_CPU_THIS_PTR activity_state);
  
  Bit32u interruptibility_state = 0;
  if (interrupts_inhibited(BX_INHIBIT_INTERRUPTS)) {
     if (interrupts_inhibited(BX_INHIBIT_DEBUG))
        interruptibility_state |= BX_VMX_INTERRUPTS_BLOCKED_BY_MOV_SS;
     else
        interruptibility_state |= BX_VMX_INTERRUPTS_BLOCKED_BY_STI;
  }

  if (is_masked_event(BX_EVENT_SMI))
    interruptibility_state |= BX_VMX_INTERRUPTS_BLOCKED_SMI_BLOCKED;
  
  if (vm->vmexec_ctrls1 & VMX_VM_EXEC_CTRL1_VIRTUAL_NMI) {
    if (is_masked_event(BX_EVENT_VMX_VIRTUAL_NMI))
      interruptibility_state |= BX_VMX_INTERRUPTS_BLOCKED_NMI_BLOCKED;
  }
  else {
    if (is_masked_event(BX_EVENT_NMI))
      interruptibility_state |= BX_VMX_INTERRUPTS_BLOCKED_NMI_BLOCKED;
  }

  VMwrite32(VMCS_32BIT_GUEST_INTERRUPTIBILITY_STATE, interruptibility_state);

#if BX_SUPPORT_VMX >= 2
  if (VMX_MSR_MISC & VMX_MISC_STORE_LMA_TO_X86_64_GUEST_VMENTRY_CONTROL) {
    // VMEXITs store the value of EFER.LMA into the <20>x86-64 guest" VMENTRY control
    // must be set if unrestricted guest is supported
    if (long_mode())
       vm->vmentry_ctrls |=  VMX_VMENTRY_CTRL1_X86_64_GUEST;
    else
       vm->vmentry_ctrls &= ~VMX_VMENTRY_CTRL1_X86_64_GUEST;
      
    VMwrite32(VMCS_32BIT_CONTROL_VMENTRY_CONTROLS, vm->vmentry_ctrls);
  }

  // Deactivate VMX preemtion timer
  BX_CPU_THIS_PTR lapic.deactivate_vmx_preemption_timer();
  clear_event(BX_EVENT_VMX_PREEMPTION_TIMER_EXPIRED);
  // Store back to VMCS
  if (vm->vmexit_ctrls & VMX_VMEXIT_CTRL1_STORE_VMX_PREEMPTION_TIMER)
    VMwrite32(VMCS_32BIT_GUEST_PREEMPTION_TIMER_VALUE, BX_CPU_THIS_PTR lapic.read_vmx_preemption_timer());

  if (vm->vmexec_ctrls3 & VMX_VM_EXEC_CTRL3_VIRTUAL_INT_DELIVERY) {
    VMwrite16(VMCS_16BIT_GUEST_INTERRUPT_STATUS, (((Bit16u) vm->svi) << 8) | vm->rvi);
  }
#endif
}

void BX_CPU_C::VMexitLoadHostState(void)
{
  VMCS_HOST_STATE *host_state = &BX_CPU_THIS_PTR vmcs.host_state;
  bx_bool x86_64_host = 0;
  Bit32u vmexit_ctrls = BX_CPU_THIS_PTR vmcs.vmexit_ctrls;

  BX_CPU_THIS_PTR tsc_offset = 0;

#if BX_SUPPORT_X86_64
  if (vmexit_ctrls & VMX_VMEXIT_CTRL1_HOST_ADDR_SPACE_SIZE) {
     BX_DEBUG(("VMEXIT to x86-64 host"));
     x86_64_host = 1;
  }

#if BX_SUPPORT_VMX >= 2
  // modify EFER.LMA / EFER.LME before setting CR4
  if (vmexit_ctrls & VMX_VMEXIT_CTRL1_LOAD_EFER_MSR) {
     BX_CPU_THIS_PTR efer.set32((Bit32u) host_state->efer_msr);
  }
  else
#endif
  {
    if (x86_64_host)
       BX_CPU_THIS_PTR efer.set32(BX_CPU_THIS_PTR efer.get32() |  (BX_EFER_LME_MASK | BX_EFER_LMA_MASK));
    else
       BX_CPU_THIS_PTR efer.set32(BX_CPU_THIS_PTR efer.get32() & ~(BX_EFER_LME_MASK | BX_EFER_LMA_MASK));
  }
#endif

  // ET, CD, NW, 28:19, 17, 15:6, and VMX fixed bits not modified Section 19.8
  host_state->cr0 = (BX_CPU_THIS_PTR cr0.get32() & VMX_KEEP_CR0_BITS) | (host_state->cr0 & ~VMX_KEEP_CR0_BITS);

  if (! check_CR0(host_state->cr0)) {
    BX_PANIC(("VMEXIT CR0 is broken !"));
  }
  if (! check_CR4(host_state->cr4)) {
    BX_PANIC(("VMEXIT CR4 is broken !"));
  }

  BX_CPU_THIS_PTR cr0.set32((Bit32u) host_state->cr0);
  BX_CPU_THIS_PTR cr4.set32((Bit32u) host_state->cr4);
  BX_CPU_THIS_PTR cr3 = host_state->cr3;

  if (! x86_64_host && BX_CPU_THIS_PTR cr4.get_PAE()) {
    if (! CheckPDPTR(host_state->cr3)) {
      BX_ERROR(("VMABORT: host PDPTRs are corrupted !"));
      VMabort(VMABORT_HOST_PDPTR_CORRUPTED);
    }
  }

  BX_CPU_THIS_PTR dr7.set32(0x00000400);

  BX_CPU_THIS_PTR msr.sysenter_cs_msr = host_state->sysenter_cs_msr;
  BX_CPU_THIS_PTR msr.sysenter_esp_msr = host_state->sysenter_esp_msr;
  BX_CPU_THIS_PTR msr.sysenter_eip_msr = host_state->sysenter_eip_msr;

#if BX_SUPPORT_VMX >= 2
  if (vmexit_ctrls & VMX_VMEXIT_CTRL1_LOAD_PAT_MSR) {
    BX_CPU_THIS_PTR msr.pat = host_state->pat_msr;
  }
#endif

  // CS selector loaded from VMCS
  //    valid   <= 1
  //    base    <= 0
  //    limit   <= 0xffffffff, g <= 1
  //    present <= 1
  //    dpl     <= 0
  //    type    <= segment, BX_CODE_EXEC_READ_ACCESSED
  //    d_b     <= loaded from 'host-address space size' VMEXIT control
  //    l       <= loaded from 'host-address space size' VMEXIT control

  parse_selector(host_state->segreg_selector[BX_SEG_REG_CS],
               &BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector);

  BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.valid    = SegValidCache | SegAccessROK | SegAccessWOK;
  BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.p        = 1;
  BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.dpl      = 0;
  BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.segment  = 1;  /* data/code segment */
  BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.type     = BX_CODE_EXEC_READ_ACCESSED;

  BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.base         = 0;
  BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.limit_scaled = 0xffffffff;
  BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.avl = 0;
  BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.g   = 1; /* page granular */
  BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.d_b = !x86_64_host;
#if BX_SUPPORT_X86_64
  BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.l   =  x86_64_host;
#endif

  // DATA selector loaded from VMCS
  //    valid   <= if selector is not all-zero
  //    base    <= 0
  //    limit   <= 0xffffffff, g <= 1
  //    present <= 1
  //    dpl     <= 0
  //    type    <= segment, BX_DATA_READ_WRITE_ACCESSED
  //    d_b     <= 1
  //    l       <= 0

  for (unsigned segreg = 0; segreg < 6; segreg++)
  {
    if (segreg == BX_SEG_REG_CS) continue;

    parse_selector(host_state->segreg_selector[segreg],
               &BX_CPU_THIS_PTR sregs[segreg].selector);

    if (! host_state->segreg_selector[segreg]) {
       BX_CPU_THIS_PTR sregs[segreg].cache.valid    = 0;
    }
    else {
       BX_CPU_THIS_PTR sregs[segreg].cache.valid    = SegValidCache;
       BX_CPU_THIS_PTR sregs[segreg].cache.p        = 1;
       BX_CPU_THIS_PTR sregs[segreg].cache.dpl      = 0;
       BX_CPU_THIS_PTR sregs[segreg].cache.segment  = 1;  /* data/code segment */
       BX_CPU_THIS_PTR sregs[segreg].cache.type     = BX_DATA_READ_WRITE_ACCESSED;
       BX_CPU_THIS_PTR sregs[segreg].cache.u.segment.base         = 0;
       BX_CPU_THIS_PTR sregs[segreg].cache.u.segment.limit_scaled = 0xffffffff;
       BX_CPU_THIS_PTR sregs[segreg].cache.u.segment.avl = 0;
       BX_CPU_THIS_PTR sregs[segreg].cache.u.segment.g   = 1; /* page granular */
       BX_CPU_THIS_PTR sregs[segreg].cache.u.segment.d_b = 1;
#if BX_SUPPORT_X86_64
       BX_CPU_THIS_PTR sregs[segreg].cache.u.segment.l   = 0;
#endif
    }
  }

  // SS.DPL always clear 
  BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.dpl = 0;

  if (x86_64_host || BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].cache.valid)
    BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].cache.u.segment.base = host_state->fs_base;

  if (x86_64_host || BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].cache.valid)
    BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].cache.u.segment.base = host_state->gs_base;

  // TR selector loaded from VMCS
  parse_selector(host_state->tr_selector, &BX_CPU_THIS_PTR tr.selector);

  BX_CPU_THIS_PTR tr.cache.valid    = 1; /* valid */
  BX_CPU_THIS_PTR tr.cache.p        = 1; /* present */
  BX_CPU_THIS_PTR tr.cache.dpl      = 0; /* field not used */
  BX_CPU_THIS_PTR tr.cache.segment  = 0; /* system segment */
  BX_CPU_THIS_PTR tr.cache.type     = BX_SYS_SEGMENT_BUSY_386_TSS;
  BX_CPU_THIS_PTR tr.cache.u.segment.base         = host_state->tr_base;
  BX_CPU_THIS_PTR tr.cache.u.segment.limit_scaled = 0x67;
  BX_CPU_THIS_PTR tr.cache.u.segment.avl = 0;
  BX_CPU_THIS_PTR tr.cache.u.segment.g   = 0; /* byte granular */

  // unusable LDTR
  BX_CPU_THIS_PTR ldtr.selector.value = 0x0000;
  BX_CPU_THIS_PTR ldtr.selector.index = 0x0000;
  BX_CPU_THIS_PTR ldtr.selector.ti    = 0;
  BX_CPU_THIS_PTR ldtr.selector.rpl   = 0;
  BX_CPU_THIS_PTR ldtr.cache.valid    = 0; /* invalid */

  BX_CPU_THIS_PTR gdtr.base = host_state->gdtr_base;
  BX_CPU_THIS_PTR gdtr.limit = 0xFFFF;

  BX_CPU_THIS_PTR idtr.base = host_state->idtr_base;
  BX_CPU_THIS_PTR idtr.limit = 0xFFFF;

  RIP = BX_CPU_THIS_PTR prev_rip = host_state->rip;
  RSP = host_state->rsp;

  BX_CPU_THIS_PTR inhibit_mask = 0;
  BX_CPU_THIS_PTR debug_trap = 0;

  // set flags directly, avoid setEFlags side effects
  BX_CPU_THIS_PTR eflags = 0x2; // Bit1 is always set
  // Update lazy flags state
  setEFlagsOSZAPC(0);

  BX_CPU_THIS_PTR activity_state = BX_ACTIVITY_STATE_ACTIVE;

  handleCpuContextChange();

#if BX_SUPPORT_MONITOR_MWAIT
  BX_CPU_THIS_PTR monitor.reset_monitor();
#endif

  BX_INSTR_TLB_CNTRL(BX_CPU_ID, BX_INSTR_CONTEXT_SWITCH, 0);
}

void BX_CPU_C::VMexit(Bit32u reason, Bit64u qualification)
{
  VMCS_CACHE *vm = &BX_CPU_THIS_PTR vmcs;

  if (!BX_CPU_THIS_PTR in_vmx || !BX_CPU_THIS_PTR in_vmx_guest) {
    if ((reason & 0x80000000) == 0)
      BX_PANIC(("PANIC: VMEXIT not in VMX guest mode !"));
  }

  //
  // STEP 0: Update VMEXIT reason
  //

  VMwrite32(VMCS_32BIT_VMEXIT_REASON, reason);
  VMwrite_natural(VMCS_VMEXIT_QUALIFICATION, qualification);

  // clipping with 0xf not really necessary but keep it for safety
  VMwrite32(VMCS_32BIT_VMEXIT_INSTRUCTION_LENGTH, (RIP-BX_CPU_THIS_PTR prev_rip) & 0xf);

  reason &= 0xffff; /* keep only basic VMEXIT reason */

  if (reason >= VMX_VMEXIT_LAST_REASON)
    BX_PANIC(("PANIC: broken VMEXIT reason %d", reason));
  else
    BX_ERROR(("VMEXIT reason = %d (%s) qualification=0x" FMT_LL "x", reason, VMX_vmexit_reason_name[reason], qualification));

  if (reason != VMX_VMEXIT_EXCEPTION_NMI && reason != VMX_VMEXIT_EXTERNAL_INTERRUPT) {
    VMwrite32(VMCS_32BIT_VMEXIT_INTERRUPTION_INFO, 0);
  }

  if (BX_CPU_THIS_PTR in_event) {
    VMwrite32(VMCS_32BIT_IDT_VECTORING_INFO, vm->idt_vector_info | 0x80000000);
    VMwrite32(VMCS_32BIT_IDT_VECTORING_ERR_CODE, vm->idt_vector_error_code);
    BX_CPU_THIS_PTR in_event = 0;
  }
  else {
    VMwrite32(VMCS_32BIT_IDT_VECTORING_INFO, 0);
  }

  BX_CPU_THIS_PTR nmi_unblocking_iret = 0;

  // VMEXITs are FAULT-like: restore RIP/RSP to value before VMEXIT occurred
  if (! IS_TRAP_LIKE_VMEXIT(reason)) {
    RIP = BX_CPU_THIS_PTR prev_rip;
    if (BX_CPU_THIS_PTR speculative_rsp)
      RSP = BX_CPU_THIS_PTR prev_rsp;
  }

  //
  // STEP 1: Saving Guest State to VMCS
  //
  if (reason != VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE && reason != VMX_VMEXIT_VMENTRY_FAILURE_MSR) {
    // clear VMENTRY interruption info field
    VMwrite32(VMCS_32BIT_CONTROL_VMENTRY_INTERRUPTION_INFO, vm->vmentry_interr_info & ~0x80000000);

    VMexitSaveGuestState();

    Bit32u msr = StoreMSRs(vm->vmexit_msr_store_cnt, vm->vmexit_msr_store_addr);
    if (msr) { 
      BX_ERROR(("VMABORT: Error when saving guest MSR number %d", msr));
      VMabort(VMABORT_SAVING_GUEST_MSRS_FAILURE);
    }
  }

  BX_CPU_THIS_PTR in_vmx_guest = 0;

  // entering VMX root mode: clear possibly pending guest VMX events
  clear_event(BX_EVENT_VMX_VTPR_UPDATE |
              BX_EVENT_VMX_VEOI_UPDATE |
              BX_EVENT_VMX_VIRTUAL_APIC_WRITE |
              BX_EVENT_VMX_MONITOR_TRAP_FLAG |
              BX_EVENT_VMX_INTERRUPT_WINDOW_EXITING |
              BX_EVENT_VMX_PREEMPTION_TIMER_EXPIRED |
              BX_EVENT_VMX_VIRTUAL_NMI |
              BX_EVENT_PENDING_VMX_VIRTUAL_INTR);

  //
  // STEP 2: Load Host State
  //
  VMexitLoadHostState();

  //
  // STEP 3: Load Host MSR registers
  //

  Bit32u msr = LoadMSRs(vm->vmexit_msr_load_cnt, vm->vmexit_msr_load_addr);
  if (msr) {
    BX_ERROR(("VMABORT: Error when loading host MSR number %d", msr));
    VMabort(VMABORT_LOADING_HOST_MSRS);
  }

  //
  // STEP 4: Go back to VMX host
  //

  mask_event(BX_EVENT_INIT); // INIT is disabled in VMX root mode

  BX_CPU_THIS_PTR EXT = 0;
  BX_CPU_THIS_PTR last_exception_type = 0;

#if BX_DEBUGGER
  if (BX_CPU_THIS_PTR vmexit_break) {
    BX_CPU_THIS_PTR stop_reason = STOP_VMEXIT_BREAK_POINT;
    bx_debug_break(); // trap into debugger
  }
#endif

  if (! IS_TRAP_LIKE_VMEXIT(reason)) {
    longjmp(BX_CPU_THIS_PTR jmp_buf_env, 1); // go back to main decode loop
  }
}

#endif // BX_SUPPORT_VMX

////////////////////////////////////////////////////////////
// VMX instructions
////////////////////////////////////////////////////////////

BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::VMXON(bxInstruction_c *i)
{
#if BX_SUPPORT_VMX
  if (! BX_CPU_THIS_PTR cr4.get_VMXE() || ! protected_mode() || BX_CPU_THIS_PTR cpu_mode == BX_MODE_LONG_COMPAT)
    exception(BX_UD_EXCEPTION, 0);

  if (! BX_CPU_THIS_PTR in_vmx) {
    if (CPL != 0 || ! BX_CPU_THIS_PTR cr0.get_NE() || 
        ! (BX_CPU_THIS_PTR cr0.get_PE()) || BX_GET_ENABLE_A20() == 0 ||
        ! (BX_CPU_THIS_PTR msr.ia32_feature_ctrl & BX_IA32_FEATURE_CONTROL_LOCK_BIT) ||
        ! (BX_CPU_THIS_PTR msr.ia32_feature_ctrl & BX_IA32_FEATURE_CONTROL_VMX_ENABLE_BIT))
    {
      BX_ERROR(("#GP: VMXON is not allowed !"));
      exception(BX_GP_EXCEPTION, 0);
    }

    bx_address eaddr = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
    Bit64u pAddr = read_virtual_qword(i->seg(), eaddr); // keep 64-bit
    if (! IsValidPageAlignedPhyAddr(pAddr)) {
      BX_ERROR(("VMXON: invalid or not page aligned physical address !"));
      VMfailInvalid();
      BX_NEXT_INSTR(i);
    }

    // not allowed to be shadow VMCS
    Bit32u revision = VMXReadRevisionID((bx_phy_address) pAddr);
    if (revision != VMX_VMCS_REVISION_ID) {
      BX_ERROR(("VMXON: not expected (%d != %d) VMCS revision id !", revision, VMX_VMCS_REVISION_ID));
      VMfailInvalid();
      BX_NEXT_INSTR(i);
    }
      
    BX_CPU_THIS_PTR vmcsptr = BX_INVALID_VMCSPTR;
    BX_CPU_THIS_PTR vmcshostptr = 0;
    BX_CPU_THIS_PTR vmxonptr = pAddr;
    BX_CPU_THIS_PTR in_vmx = 1;
    mask_event(BX_EVENT_INIT); // INIT is disabled in VMX root mode
    // block and disable A20M;

#if BX_SUPPORT_MONITOR_MWAIT
    BX_CPU_THIS_PTR monitor.reset_monitor();
#endif

    VMsucceed();
  }
  else if (BX_CPU_THIS_PTR in_vmx_guest) { // in VMX non-root operation
    VMexit_Instruction(i, VMX_VMEXIT_VMXON);
  }
  else {
    // in VMX root operation mode
    if (CPL != 0) {
      BX_ERROR(("VMXON with CPL!=0 cause #GP(0)"));
      exception(BX_GP_EXCEPTION, 0);
    }

    VMfail(VMXERR_VMXON_IN_VMX_ROOT_OPERATION);
  }
#endif  

  BX_NEXT_INSTR(i);
}

BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::VMXOFF(bxInstruction_c *i)
{
#if BX_SUPPORT_VMX
  if (! BX_CPU_THIS_PTR in_vmx || ! protected_mode() || BX_CPU_THIS_PTR cpu_mode == BX_MODE_LONG_COMPAT)
    exception(BX_UD_EXCEPTION, 0);

  if (BX_CPU_THIS_PTR in_vmx_guest) {
    VMexit(VMX_VMEXIT_VMXOFF, 0);
  }

  if (CPL != 0) {
    BX_ERROR(("VMXOFF with CPL!=0 cause #GP(0)"));
    exception(BX_GP_EXCEPTION, 0);
  }

/*
        if dual-monitor treatment of SMIs and SMM is active
                THEN VMfail(VMXERR_VMXOFF_WITH_CONFIGURED_SMM_MONITOR);
        else
*/
  {
    BX_CPU_THIS_PTR vmxonptr = BX_INVALID_VMCSPTR;
    BX_CPU_THIS_PTR in_vmx = 0;  // leave VMX operation mode
    unmask_event(BX_EVENT_INIT);
     // unblock and enable A20M;
#if BX_SUPPORT_MONITOR_MWAIT
    BX_CPU_THIS_PTR monitor.reset_monitor();
#endif
    VMsucceed();
  }
#endif  

  BX_NEXT_INSTR(i);
}

BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::VMCALL(bxInstruction_c *i)
{
#if BX_SUPPORT_VMX
  if (! BX_CPU_THIS_PTR in_vmx)
    exception(BX_UD_EXCEPTION, 0);

  if (BX_CPU_THIS_PTR in_vmx_guest) {
    VMexit(VMX_VMEXIT_VMCALL, 0);
  }

  if (BX_CPU_THIS_PTR get_VM() || BX_CPU_THIS_PTR cpu_mode == BX_MODE_LONG_COMPAT)
    exception(BX_UD_EXCEPTION, 0);

  if (CPL != 0) {
    BX_ERROR(("VMCALL with CPL!=0 cause #GP(0)"));
    exception(BX_GP_EXCEPTION, 0);
  }

  if (BX_CPU_THIS_PTR in_smm /*|| 
        (the logical processor does not support the dual-monitor treatment of SMIs and SMM) ||
        (the valid bit in the IA32_SMM_MONITOR_CTL MSR is clear)*/)
  {
    VMfail(VMXERR_VMCALL_IN_VMX_ROOT_OPERATION);
    BX_NEXT_TRACE(i);
  }
/*
        if dual-monitor treatment of SMIs and BX_CPU_THIS_PTR in_smm
                THEN perform an SMM VMexit (see Section 24.16.2
                     of the IntelR 64 and IA-32 Architectures Software Developer's Manual, Volume 3B);
*/
  if (BX_CPU_THIS_PTR vmcsptr == BX_INVALID_VMCSPTR) {
    BX_ERROR(("VMFAIL: VMCALL with invalid VMCS ptr"));
    VMfailInvalid();
    BX_NEXT_TRACE(i);
  }

  Bit32u launch_state;
  access_read_physical(BX_CPU_THIS_PTR vmcsptr + VMCS_LAUNCH_STATE_FIELD_ADDR, 4, &launch_state);
  BX_NOTIFY_PHY_MEMORY_ACCESS(BX_CPU_THIS_PTR vmcsptr + VMCS_LAUNCH_STATE_FIELD_ADDR, 4,
        BX_READ, BX_VMCS_ACCESS, (Bit8u*)(&launch_state));

  if (launch_state != VMCS_STATE_CLEAR) {
    BX_ERROR(("VMFAIL: VMCALL with launched VMCS"));
    VMfail(VMXERR_VMCALL_NON_CLEAR_VMCS);
    BX_NEXT_TRACE(i);
  }

  BX_PANIC(("VMCALL: not implemented yet"));
/*
  if VM-exit control fields are not valid (see Section 24.16.6.1 of the IntelR 64 and IA-32 Architectures Software Developer's Manual, Volume 3B)
      THEN VMfail(VMXERR_VMCALL_INVALID_VMEXIT_FIELD);
   else
      enter SMM;
      read revision identifier in MSEG;
      if revision identifier does not match that supported by processor
      THEN
          leave SMM;
          VMfailValid(VMXERR_VMCALL_INVALID_MSEG_REVISION_ID);
      else
          read SMM-monitor features field in MSEG (see Section 24.16.6.2,
          in the IntelR 64 and IA-32 Architectures Software Developer's Manual, Volume 3B);
          if features field is invalid
          THEN
              leave SMM;
              VMfailValid(VMXERR_VMCALL_WITH_INVALID_SMM_MONITOR_FEATURES);
          else activate dual-monitor treatment of SMIs and SMM (see Section 24.16.6
              in the IntelR 64 and IA-32 Architectures Software Developer's Manual, Volume 3B);
          FI;
      FI;
  FI;
*/
#endif  

  BX_NEXT_TRACE(i);
}

BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::VMLAUNCH(bxInstruction_c *i)
{
#if BX_SUPPORT_VMX
  if (! BX_CPU_THIS_PTR in_vmx || ! protected_mode() || BX_CPU_THIS_PTR cpu_mode == BX_MODE_LONG_COMPAT)
    exception(BX_UD_EXCEPTION, 0);

  unsigned vmlaunch = 0;
  if ((i->getIaOpcode() == BX_IA_VMLAUNCH)) {
    BX_DEBUG(("VMLAUNCH VMCS ptr: 0x" FMT_ADDRX64, BX_CPU_THIS_PTR vmcsptr));
    vmlaunch = 1;
  }
  else {
    BX_DEBUG(("VMRESUME VMCS ptr: 0x" FMT_ADDRX64, BX_CPU_THIS_PTR vmcsptr));
  }

  if (BX_CPU_THIS_PTR in_vmx_guest) {
    VMexit(vmlaunch ? VMX_VMEXIT_VMLAUNCH : VMX_VMEXIT_VMRESUME, 0);
  }

  if (CPL != 0) {
    BX_ERROR(("VMLAUNCH/VMRESUME with CPL!=0 cause #GP(0)"));
    exception(BX_GP_EXCEPTION, 0);
  }

  if (BX_CPU_THIS_PTR vmcsptr == BX_INVALID_VMCSPTR) {
    BX_ERROR(("VMFAIL: VMLAUNCH with invalid VMCS ptr !"));
    VMfailInvalid();
    BX_NEXT_TRACE(i);
  }

  if (interrupts_inhibited(BX_INHIBIT_INTERRUPTS_BY_MOVSS)) {
    BX_ERROR(("VMFAIL: VMLAUNCH with interrupts blocked by MOV_SS !"));
    VMfail(VMXERR_VMENTRY_MOV_SS_BLOCKING);
    BX_NEXT_TRACE(i);
  }

  Bit32u launch_state;
  access_read_physical(BX_CPU_THIS_PTR vmcsptr + VMCS_LAUNCH_STATE_FIELD_ADDR, 4, &launch_state);
  BX_NOTIFY_PHY_MEMORY_ACCESS(BX_CPU_THIS_PTR vmcsptr + VMCS_LAUNCH_STATE_FIELD_ADDR, 4,
        BX_READ, BX_VMCS_ACCESS, (Bit8u*)(&launch_state));

  if (vmlaunch) {
    if (launch_state != VMCS_STATE_CLEAR) {
       BX_ERROR(("VMFAIL: VMLAUNCH with non-clear VMCS!"));
       VMfail(VMXERR_VMLAUNCH_NON_CLEAR_VMCS);
       BX_NEXT_TRACE(i);
    }
  }
  else {
    if (launch_state != VMCS_STATE_LAUNCHED) {
       BX_ERROR(("VMFAIL: VMRESUME with non-launched VMCS!"));
       VMfail(VMXERR_VMRESUME_NON_LAUNCHED_VMCS);
       BX_NEXT_TRACE(i);
    }
  }

  ///////////////////////////////////////////////////////
  // STEP 1: Load and Check VM-Execution Control Fields
  // STEP 2: Load and Check VM-Exit Control Fields
  // STEP 3: Load and Check VM-Entry Control Fields
  ///////////////////////////////////////////////////////

  VMX_error_code error = VMenterLoadCheckVmControls();
  if (error != VMXERR_NO_ERROR) {
    VMfail(error);
    BX_NEXT_TRACE(i);
  }

  ///////////////////////////////////////////////////////
  // STEP 4: Load and Check Host State
  ///////////////////////////////////////////////////////

  error = VMenterLoadCheckHostState();
  if (error != VMXERR_NO_ERROR) {
    VMfail(error);
    BX_NEXT_TRACE(i);
  }

  ///////////////////////////////////////////////////////
  // STEP 5: Load and Check Guest State
  ///////////////////////////////////////////////////////

  Bit64u qualification = VMENTER_ERR_NO_ERROR;
  Bit32u state_load_error = VMenterLoadCheckGuestState(&qualification);
  if (state_load_error) {
    BX_ERROR(("VMEXIT: Guest State Checks Failed"));
    VMexit(VMX_VMEXIT_VMENTRY_FAILURE_GUEST_STATE | (1 << 31), qualification);
  }

  Bit32u msr = LoadMSRs(BX_CPU_THIS_PTR vmcs.vmentry_msr_load_cnt, BX_CPU_THIS_PTR vmcs.vmentry_msr_load_addr);
  if (msr) {
    BX_ERROR(("VMEXIT: Error when loading guest MSR 0x%08x", msr));
    VMexit(VMX_VMEXIT_VMENTRY_FAILURE_MSR | (1 << 31), msr);
  }

  ///////////////////////////////////////////////////////
  // STEP 6: Update VMCS 'launched' state
  ///////////////////////////////////////////////////////
 
  if (vmlaunch) {
    launch_state = VMCS_STATE_LAUNCHED;
    bx_phy_address pAddr = BX_CPU_THIS_PTR vmcsptr + VMCS_LAUNCH_STATE_FIELD_ADDR;
    access_write_physical(pAddr, 4, &launch_state);
    BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr, 4, BX_WRITE, BX_VMCS_ACCESS, (Bit8u*)(&launch_state));
  }

/*
   Check settings of VMX controls and host-state area;
   if invalid settings
   THEN VMfailValid(VM entry with invalid VMX-control field(s)) or
        VMfailValid(VM entry with invalid host-state field(s)) or
        VMfailValid(VM entry with invalid executive-VMCS pointer)) or
        VMfailValid(VM entry with non-launched executive VMCS) or
        VMfailValid(VM entry with executive-VMCS pointer not VMXON pointer)
        VMfailValid(VM entry with invalid VM-execution control fields in executive VMCS)
   (as appropriate);
   else
        Attempt to load guest state and PDPTRs as appropriate;
        clear address-range monitoring;
        if failure in checking guest state or PDPTRs
        	THEN VM entry fails (see Section 22.7, in the IntelR 64 and IA-32 Architectures Software Developer's Manual, Volume 3B);
        else
                Attempt to load MSRs from VM-entry MSR-load area;
                if failure
                	THEN VM entry fails (see Section 22.7, in the IntelR 64 and IA-32 Architectures Software Developer's Manual, Volume 3B);
                else {
                        if VMLAUNCH
                        	THEN launch state of VMCS <== "launched";
                                if in SMM and "entry to SMM" VM-entry control is 0
                                THEN
                                	if "deactivate dual-monitor treatment" VM-entry control is 0
                                        	THEN SMM-transfer VMCS pointer <== current-VMCS pointer;
                                        FI;
                                        if executive-VMCS pointer is VMX pointer
                                        	THEN current-VMCS pointer <== VMCS-link pointer;
                                        else current-VMCS pointer <== executive-VMCS pointer;
                                FI;
                                leave SMM;
                        FI;
                        VMsucceed();
                }
         FI;
   FI;
*/

  BX_CPU_THIS_PTR in_vmx_guest = 1;

  unmask_event(BX_EVENT_INIT);

  if (VMEXIT(VMX_VM_EXEC_CTRL2_TSC_OFFSET))
    BX_CPU_THIS_PTR tsc_offset = VMread64(VMCS_64BIT_CONTROL_TSC_OFFSET);
  else
    BX_CPU_THIS_PTR tsc_offset = 0;

#if BX_SUPPORT_VMX >= 2
  if (PIN_VMEXIT(VMX_VM_EXEC_CTRL1_VMX_PREEMPTION_TIMER_VMEXIT)) {
    Bit32u timer_value = VMread32(VMCS_32BIT_GUEST_PREEMPTION_TIMER_VALUE);
    if (timer_value == 0) {
      signal_event(BX_EVENT_VMX_PREEMPTION_TIMER_EXPIRED);
    }
    else {
      // activate VMX preemption timer
      BX_DEBUG(("VMX preemption timer active"));
      BX_CPU_THIS_PTR lapic.set_vmx_preemption_timer(timer_value);
    }
  }
#endif

  ///////////////////////////////////////////////////////
  // STEP 7: Inject events to the guest
  ///////////////////////////////////////////////////////

  VMenterInjectEvents();

#if BX_SUPPORT_X86_64
  // - When virtual-interrupt-delivery is set this will cause PPR virtualization
  //   followed by Virtual Interrupt Evaluation
  // - When use TPR shadow together with Virtualize APIC Access are set this would
  //   cause TPR threshold check
  // - When Virtualize APIC Access is disabled the code would pass through TPR
  //   threshold check but no VMExit would occur (otherwise VMEntry should fail
  //   consistency checks before).
  if (VMEXIT(VMX_VM_EXEC_CTRL2_TPR_SHADOW)) {
    VMX_TPR_Virtualization();
  }
#endif

#endif // BX_SUPPORT_VMX

  BX_NEXT_TRACE(i);
}

BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::VMPTRLD(bxInstruction_c *i)
{
#if BX_SUPPORT_VMX
  if (! BX_CPU_THIS_PTR in_vmx || ! protected_mode() || BX_CPU_THIS_PTR cpu_mode == BX_MODE_LONG_COMPAT)
    exception(BX_UD_EXCEPTION, 0);

  if (BX_CPU_THIS_PTR in_vmx_guest) {
    VMexit_Instruction(i, VMX_VMEXIT_VMPTRLD);
  }

  if (CPL != 0) {
    BX_ERROR(("VMPTRLD with CPL!=0 willcause #GP(0)"));
    exception(BX_GP_EXCEPTION, 0);
  }

  bx_address eaddr = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
  Bit64u pAddr = read_virtual_qword(i->seg(), eaddr); // keep 64-bit
  if (! IsValidPageAlignedPhyAddr(pAddr)) {
    BX_ERROR(("VMFAIL: invalid or not page aligned physical address !"));
    VMfail(VMXERR_VMPTRLD_INVALID_PHYSICAL_ADDRESS);
    BX_NEXT_INSTR(i);
  }

  if (pAddr == BX_CPU_THIS_PTR vmxonptr) {
    BX_ERROR(("VMFAIL: VMPTRLD with VMXON ptr !"));
    VMfail(VMXERR_VMPTRLD_WITH_VMXON_PTR);
  }
  else {
    Bit32u revision = VMXReadRevisionID((bx_phy_address) pAddr);

    if (BX_SUPPORT_VMX_EXTENSION(BX_VMX_VMCS_SHADOWING))
      revision &= ~BX_VMCS_SHADOW_BIT_MASK; // allowed to be shadow VMCS

    if (revision != VMX_VMCS_REVISION_ID) {
       BX_ERROR(("VMPTRLD: not expected (%d != %d) VMCS revision id !", revision, VMX_VMCS_REVISION_ID));
       VMfail(VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID);
    }
    else {
       set_VMCSPTR(pAddr);
       VMsucceed();
    }
  }
#endif  

  BX_NEXT_INSTR(i);
}

BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::VMPTRST(bxInstruction_c *i)
{
#if BX_SUPPORT_VMX
  if (! BX_CPU_THIS_PTR in_vmx || ! protected_mode() || BX_CPU_THIS_PTR cpu_mode == BX_MODE_LONG_COMPAT)
    exception(BX_UD_EXCEPTION, 0);

  if (BX_CPU_THIS_PTR in_vmx_guest) {
    VMexit_Instruction(i, VMX_VMEXIT_VMPTRST);
  }

  if (CPL != 0) {
    BX_ERROR(("VMPTRST with CPL!=0 cause #GP(0)"));
    exception(BX_GP_EXCEPTION, 0);
  }

  bx_address eaddr = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
  write_virtual_qword(i->seg(), eaddr, BX_CPU_THIS_PTR vmcsptr);
  VMsucceed();
#endif  

  BX_NEXT_INSTR(i);
}

#if BX_SUPPORT_VMX

Bit64u BX_CPP_AttrRegparmN(1) BX_CPU_C::vmread(unsigned encoding)
{
  unsigned width = VMCS_FIELD_WIDTH(encoding);
  Bit64u field_64;

  if(width == VMCS_FIELD_WIDTH_16BIT) {
    field_64 = VMread16(encoding);
  }
  else if(width == VMCS_FIELD_WIDTH_32BIT) {
    // the real hardware write access rights rotated
    if (encoding >= VMCS_32BIT_GUEST_ES_ACCESS_RIGHTS && encoding <= VMCS_32BIT_GUEST_TR_ACCESS_RIGHTS)
      field_64 = vmx_from_ar_byte_rd(VMread32(encoding));
    else
      field_64 = VMread32(encoding);
  }
  else if(width == VMCS_FIELD_WIDTH_64BIT) {
    if (IS_VMCS_FIELD_HI(encoding))
      field_64 = VMread32(encoding);
    else
      field_64 = VMread64(encoding);
  }
  else {
    field_64 = VMread_natural(encoding);
  }

  return field_64;
}

void BX_CPP_AttrRegparmN(2) BX_CPU_C::vmwrite(unsigned encoding, Bit64u val_64)
{
  unsigned width = VMCS_FIELD_WIDTH(encoding);
  Bit32u val_32 = GET32L(val_64);

  if(width == VMCS_FIELD_WIDTH_16BIT) {
    VMwrite16(encoding, val_32 & 0xffff);
  }
  else if(width == VMCS_FIELD_WIDTH_32BIT) {
    // the real hardware write access rights rotated
    if (encoding >= VMCS_32BIT_GUEST_ES_ACCESS_RIGHTS && encoding <= VMCS_32BIT_GUEST_TR_ACCESS_RIGHTS)
      VMwrite32(encoding, vmx_from_ar_byte_wr(val_32));
    else
      VMwrite32(encoding, val_32);
  }
  else if(width == VMCS_FIELD_WIDTH_64BIT) {
    if (IS_VMCS_FIELD_HI(encoding))
      VMwrite32(encoding, val_32);
    else
      VMwrite64(encoding, val_64);
  }
  else {
    VMwrite_natural(encoding, (bx_address) val_64);
  }
}

#if BX_SUPPORT_VMX >= 2

Bit64u BX_CPP_AttrRegparmN(1) BX_CPU_C::vmread_shadow(unsigned encoding)
{
  unsigned width = VMCS_FIELD_WIDTH(encoding);
  Bit64u field_64;

  if(width == VMCS_FIELD_WIDTH_16BIT) {
    field_64 = VMread16_Shadow(encoding);
  }
  else if(width == VMCS_FIELD_WIDTH_32BIT) {
    // the real hardware write access rights rotated
    if (encoding >= VMCS_32BIT_GUEST_ES_ACCESS_RIGHTS && encoding <= VMCS_32BIT_GUEST_TR_ACCESS_RIGHTS)
      field_64 = vmx_from_ar_byte_rd(VMread32_Shadow(encoding));
    else
      field_64 = VMread32_Shadow(encoding);
  }
  else if(width == VMCS_FIELD_WIDTH_64BIT) {
    if (IS_VMCS_FIELD_HI(encoding))
      field_64 = VMread32_Shadow(encoding);
    else
      field_64 = VMread64_Shadow(encoding);
  }
  else {
    field_64 = VMread64_Shadow(encoding);
  }

  return field_64;
}

void BX_CPP_AttrRegparmN(2) BX_CPU_C::vmwrite_shadow(unsigned encoding, Bit64u val_64)
{
  unsigned width = VMCS_FIELD_WIDTH(encoding);
  Bit32u val_32 = GET32L(val_64);

  if(width == VMCS_FIELD_WIDTH_16BIT) {
    VMwrite16_Shadow(encoding, val_32 & 0xffff);
  }
  else if(width == VMCS_FIELD_WIDTH_32BIT) {
    // the real hardware write access rights rotated
    if (encoding >= VMCS_32BIT_GUEST_ES_ACCESS_RIGHTS && encoding <= VMCS_32BIT_GUEST_TR_ACCESS_RIGHTS)
      VMwrite32_Shadow(encoding, vmx_from_ar_byte_wr(val_32));
    else
      VMwrite32_Shadow(encoding, val_32);
  }
  else if(width == VMCS_FIELD_WIDTH_64BIT) {
    if (IS_VMCS_FIELD_HI(encoding))
      VMwrite32_Shadow(encoding, val_32);
    else
      VMwrite64_Shadow(encoding, val_64);
  }
  else {
    VMwrite64_Shadow(encoding, val_64);
  }
}

#endif // BX_SUPPORT_VMX >= 2

#endif

BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::VMREAD_EdGd(bxInstruction_c *i)
{
#if BX_SUPPORT_VMX
  if (! BX_CPU_THIS_PTR in_vmx || ! protected_mode() || BX_CPU_THIS_PTR cpu_mode == BX_MODE_LONG_COMPAT)
    exception(BX_UD_EXCEPTION, 0);

  bx_phy_address vmcs_pointer = BX_CPU_THIS_PTR vmcsptr;

  if (BX_CPU_THIS_PTR in_vmx_guest) {
#if BX_SUPPORT_VMX >= 2
    if (Vmexit_Vmread(i))
#endif
        VMexit_Instruction(i, VMX_VMEXIT_VMREAD, BX_READ);

    vmcs_pointer = BX_CPU_THIS_PTR vmcs.vmcs_linkptr;
  }

  if (CPL != 0) {
    BX_ERROR(("VMREAD with CPL!=0 cause #GP(0)"));
    exception(BX_GP_EXCEPTION, 0);
  }

  if (vmcs_pointer == BX_INVALID_VMCSPTR) {
    BX_ERROR(("VMFAIL: VMREAD with invalid VMCS ptr !"));
    VMfailInvalid();
    BX_NEXT_INSTR(i);
  }

  unsigned encoding = BX_READ_32BIT_REG(i->src());

  if (vmcs_field_offset(encoding) == 0xffffffff) {
    BX_ERROR(("VMREAD: not supported field 0x%08x", encoding));
    VMfail(VMXERR_UNSUPPORTED_VMCS_COMPONENT_ACCESS);
    BX_NEXT_INSTR(i);
  }

  Bit32u field_32;
#if BX_SUPPORT_VMX >= 2
  if (BX_CPU_THIS_PTR in_vmx_guest)
    field_32 = (Bit32u) vmread_shadow(encoding);
  else
#endif
    field_32 = (Bit32u) vmread(encoding);

  if (i->modC0()) {
     BX_WRITE_32BIT_REGZ(i->dst(), field_32);
  }
  else {
     Bit32u eaddr = (Bit32u) BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
     write_virtual_dword_32(i->seg(), eaddr, field_32);
  }
 
  VMsucceed();
#endif  

  BX_NEXT_INSTR(i);
}

#if BX_SUPPORT_X86_64

BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::VMREAD_EqGq(bxInstruction_c *i)
{
#if BX_SUPPORT_VMX
  if (! BX_CPU_THIS_PTR in_vmx || ! protected_mode() || BX_CPU_THIS_PTR cpu_mode == BX_MODE_LONG_COMPAT)
    exception(BX_UD_EXCEPTION, 0);

  bx_phy_address vmcs_pointer = BX_CPU_THIS_PTR vmcsptr;

  if (BX_CPU_THIS_PTR in_vmx_guest) {
#if BX_SUPPORT_VMX >= 2
    if (Vmexit_Vmread(i))
#endif
        VMexit_Instruction(i, VMX_VMEXIT_VMREAD, BX_READ);

    vmcs_pointer = BX_CPU_THIS_PTR vmcs.vmcs_linkptr;
  }

  if (CPL != 0) {
    BX_ERROR(("VMREAD with CPL!=0 cause #GP(0)"));
    exception(BX_GP_EXCEPTION, 0);
  }

  if (vmcs_pointer == BX_INVALID_VMCSPTR) {
    BX_ERROR(("VMFAIL: VMREAD with invalid VMCS ptr !"));
    VMfailInvalid();
    BX_NEXT_INSTR(i);
  }

  if (BX_READ_64BIT_REG_HIGH(i->src())) {
    BX_ERROR(("VMREAD: not supported field (upper 32-bit not zero)"));
    VMfail(VMXERR_UNSUPPORTED_VMCS_COMPONENT_ACCESS);
    BX_NEXT_INSTR(i);
  }
  unsigned encoding = BX_READ_32BIT_REG(i->src());

  if (vmcs_field_offset(encoding) == 0xffffffff) {
    BX_ERROR(("VMREAD: not supported field 0x%08x", encoding));
    VMfail(VMXERR_UNSUPPORTED_VMCS_COMPONENT_ACCESS);
    BX_NEXT_INSTR(i);
  }

  Bit64u field_64;
#if BX_SUPPORT_VMX >= 2
  if (BX_CPU_THIS_PTR in_vmx_guest)
    field_64 = vmread_shadow(encoding);
  else
#endif
    field_64 = vmread(encoding);

  if (i->modC0()) {
     BX_WRITE_64BIT_REG(i->dst(), field_64);
  }
  else {
     Bit64u eaddr = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
     write_virtual_qword_64(i->seg(), eaddr, field_64);
  }
 
  VMsucceed();
#endif  

  BX_NEXT_INSTR(i);
}

#endif

BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::VMWRITE_GdEd(bxInstruction_c *i)
{
#if BX_SUPPORT_VMX
  if (! BX_CPU_THIS_PTR in_vmx || ! protected_mode() || BX_CPU_THIS_PTR cpu_mode == BX_MODE_LONG_COMPAT)
    exception(BX_UD_EXCEPTION, 0);

  bx_phy_address vmcs_pointer = BX_CPU_THIS_PTR vmcsptr;

  if (BX_CPU_THIS_PTR in_vmx_guest) {
#if BX_SUPPORT_VMX >= 2
    if (Vmexit_Vmwrite(i))
#endif
        VMexit_Instruction(i, VMX_VMEXIT_VMWRITE, BX_WRITE);

    vmcs_pointer = BX_CPU_THIS_PTR vmcs.vmcs_linkptr;
  }

  if (CPL != 0) {
    BX_ERROR(("VMWRITE with CPL!=0 cause #GP(0)"));
    exception(BX_GP_EXCEPTION, 0);
  }

  if (vmcs_pointer == BX_INVALID_VMCSPTR) {
    BX_ERROR(("VMFAIL: VMWRITE with invalid VMCS ptr !"));
    VMfailInvalid();
    BX_NEXT_INSTR(i);
  }

  Bit32u val_32;

  if (i->modC0()) {
     val_32 = BX_READ_32BIT_REG(i->src());
  }
  else {
     Bit32u eaddr = (Bit32u) BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
     val_32 = read_virtual_dword_32(i->seg(), eaddr);
  }

  Bit32u encoding = BX_READ_32BIT_REG(i->dst());

  if (vmcs_field_offset(encoding) == 0xffffffff) {
    BX_ERROR(("VMWRITE: not supported field 0x%08x", encoding));
    VMfail(VMXERR_UNSUPPORTED_VMCS_COMPONENT_ACCESS);
    BX_NEXT_INSTR(i);
  }

  if (VMCS_FIELD_TYPE(encoding) == VMCS_FIELD_TYPE_READ_ONLY)
  {
    if ((VMX_MSR_MISC & VMX_MISC_SUPPORT_VMWRITE_READ_ONLY_FIELDS) == 0) {
      BX_ERROR(("VMWRITE: write to read only field 0x%08x", encoding));
      VMfail(VMXERR_VMWRITE_READ_ONLY_VMCS_COMPONENT);
      BX_NEXT_INSTR(i);
    }
  }

#if BX_SUPPORT_VMX >= 2
  if (BX_CPU_THIS_PTR in_vmx_guest)
    vmwrite_shadow(encoding, (Bit64u) val_32);
  else
#endif
    vmwrite(encoding, (Bit64u) val_32);

  VMsucceed();
#endif  

  BX_NEXT_INSTR(i);
}

#if BX_SUPPORT_X86_64

BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::VMWRITE_GqEq(bxInstruction_c *i)
{
#if BX_SUPPORT_VMX
  if (! BX_CPU_THIS_PTR in_vmx || ! protected_mode() || BX_CPU_THIS_PTR cpu_mode == BX_MODE_LONG_COMPAT)
    exception(BX_UD_EXCEPTION, 0);

  bx_phy_address vmcs_pointer = BX_CPU_THIS_PTR vmcsptr;

  if (BX_CPU_THIS_PTR in_vmx_guest) {
#if BX_SUPPORT_VMX >= 2
    if (Vmexit_Vmwrite(i))
#endif
        VMexit_Instruction(i, VMX_VMEXIT_VMWRITE, BX_WRITE);

    vmcs_pointer = BX_CPU_THIS_PTR vmcs.vmcs_linkptr;
  }

  if (CPL != 0) {
    BX_ERROR(("VMWRITE with CPL!=0 cause #GP(0)"));
    exception(BX_GP_EXCEPTION, 0);
  }

  if (vmcs_pointer == BX_INVALID_VMCSPTR) {
    BX_ERROR(("VMFAIL: VMWRITE with invalid VMCS ptr !"));
    VMfailInvalid();
    BX_NEXT_INSTR(i);
  }

  Bit64u val_64;

  if (i->modC0()) {
     val_64 = BX_READ_64BIT_REG(i->src());
  }
  else {
     Bit64u eaddr = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
     val_64 = read_virtual_qword_64(i->seg(), eaddr);
  }

  if (BX_READ_64BIT_REG_HIGH(i->dst())) {
     BX_ERROR(("VMWRITE: not supported field (upper 32-bit not zero)"));
     VMfail(VMXERR_UNSUPPORTED_VMCS_COMPONENT_ACCESS);
     BX_NEXT_INSTR(i);
  }

  Bit32u encoding = BX_READ_32BIT_REG(i->dst());

  if (vmcs_field_offset(encoding) == 0xffffffff) {
    BX_ERROR(("VMWRITE: not supported field 0x%08x", encoding));
    VMfail(VMXERR_UNSUPPORTED_VMCS_COMPONENT_ACCESS);
    BX_NEXT_INSTR(i);
  }

  if (VMCS_FIELD_TYPE(encoding) == VMCS_FIELD_TYPE_READ_ONLY)
  {
    if ((VMX_MSR_MISC & VMX_MISC_SUPPORT_VMWRITE_READ_ONLY_FIELDS) == 0) {
      BX_ERROR(("VMWRITE: write to read only field 0x%08x", encoding));
      VMfail(VMXERR_VMWRITE_READ_ONLY_VMCS_COMPONENT);
      BX_NEXT_INSTR(i);
    }
  }

#if BX_SUPPORT_VMX >= 2
  if (BX_CPU_THIS_PTR in_vmx_guest)
    vmwrite_shadow(encoding, val_64);
  else
#endif
    vmwrite(encoding, val_64);

  VMsucceed();
#endif  

  BX_NEXT_INSTR(i);
}

#endif

BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::VMCLEAR(bxInstruction_c *i)
{
#if BX_SUPPORT_VMX
  if (! BX_CPU_THIS_PTR in_vmx || ! protected_mode() || BX_CPU_THIS_PTR cpu_mode == BX_MODE_LONG_COMPAT)
    exception(BX_UD_EXCEPTION, 0);

  if (BX_CPU_THIS_PTR in_vmx_guest) {
    VMexit_Instruction(i, VMX_VMEXIT_VMCLEAR);
  }

  if (CPL != 0) {
    BX_ERROR(("VMCLEAR with CPL!=0 cause #GP(0)"));
    exception(BX_GP_EXCEPTION, 0);
  }

  bx_address eaddr = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
  Bit64u pAddr = read_virtual_qword(i->seg(), eaddr); // keep 64-bit
  if (! IsValidPageAlignedPhyAddr(pAddr)) {
    BX_ERROR(("VMFAIL: VMCLEAR with invalid physical address!"));
    VMfail(VMXERR_VMCLEAR_WITH_INVALID_ADDR);
    BX_NEXT_INSTR(i);
  }

  if (pAddr == BX_CPU_THIS_PTR vmxonptr) {
    BX_ERROR(("VMFAIL: VMLEAR with VMXON ptr !"));
    VMfail(VMXERR_VMCLEAR_WITH_VMXON_VMCS_PTR);
  }
  else {
    // ensure that data for VMCS referenced by the operand is in memory
    // initialize implementation-specific data in VMCS region

    // clear VMCS launch state
    Bit32u launch_state = VMCS_STATE_CLEAR;
    access_write_physical(pAddr + VMCS_LAUNCH_STATE_FIELD_ADDR, 4, &launch_state);
    BX_NOTIFY_PHY_MEMORY_ACCESS(pAddr + VMCS_LAUNCH_STATE_FIELD_ADDR, 4,
            BX_WRITE, BX_VMCS_ACCESS, (Bit8u*)(&launch_state));

    if (pAddr == BX_CPU_THIS_PTR vmcsptr) {
        BX_CPU_THIS_PTR vmcsptr = BX_INVALID_VMCSPTR;
        BX_CPU_THIS_PTR vmcshostptr = 0;
    }

    VMsucceed();
  }
#endif  

  BX_NEXT_INSTR(i);
}

#if BX_CPU_LEVEL >= 6

BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::INVEPT(bxInstruction_c *i)
{
#if BX_SUPPORT_VMX >= 2
  if (! BX_CPU_THIS_PTR in_vmx || ! protected_mode() || BX_CPU_THIS_PTR cpu_mode == BX_MODE_LONG_COMPAT)
    exception(BX_UD_EXCEPTION, 0);

  if (BX_CPU_THIS_PTR in_vmx_guest) {
    VMexit_Instruction(i, VMX_VMEXIT_INVEPT, BX_READ);
  }

  if (CPL != 0) {
    BX_ERROR(("INVEPT with CPL!=0 cause #GP(0)"));
    exception(BX_GP_EXCEPTION, 0);
  }

  bx_address type;
  if (i->os64L()) {
    type = BX_READ_64BIT_REG(i->dst());
  }
  else {
    type = BX_READ_32BIT_REG(i->dst());
  }

  BxPackedXmmRegister inv_eptp;
  bx_address eaddr = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
  read_virtual_xmmword(i->seg(), eaddr, (Bit8u *) &inv_eptp);

  switch(type) {
  case BX_INVEPT_INVVPID_SINGLE_CONTEXT_INVALIDATION:
     if (! is_eptptr_valid(inv_eptp.xmm64u(0))) {
       BX_ERROR(("INVEPT: invalid EPTPTR value !"));
       VMfail(VMXERR_INVALID_INVEPT_INVVPID);
       BX_NEXT_TRACE(i);
     }
     TLB_flush(); // Invalidate mappings associated with EPTP[51:12]
     break;

  case BX_INVEPT_INVVPID_ALL_CONTEXT_INVALIDATION:
     TLB_flush(); // Invalidate mappings associated with all EPTPs
     break;

  default:
     BX_ERROR(("INVEPT: not supported type !"));
     VMfail(VMXERR_INVALID_INVEPT_INVVPID);
     BX_NEXT_TRACE(i);
  }

  BX_INSTR_TLB_CNTRL(BX_CPU_ID, BX_INSTR_INVEPT, type);

  VMsucceed();
#else
  BX_INFO(("INVEPT: required VMXx2 support, use --enable-vmx=2 option"));
  exception(BX_UD_EXCEPTION, 0);
#endif

  BX_NEXT_TRACE(i);
}

BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::INVVPID(bxInstruction_c *i)
{
#if BX_SUPPORT_VMX >= 2
  if (! BX_CPU_THIS_PTR in_vmx || ! protected_mode() || BX_CPU_THIS_PTR cpu_mode == BX_MODE_LONG_COMPAT)
    exception(BX_UD_EXCEPTION, 0);

  if (BX_CPU_THIS_PTR in_vmx_guest) {
    VMexit_Instruction(i, VMX_VMEXIT_INVVPID, BX_READ);
  }

  if (CPL != 0) {
    BX_ERROR(("INVVPID with CPL!=0 cause #GP(0)"));
    exception(BX_GP_EXCEPTION, 0);
  }

  bx_address type;
  if (i->os64L()) {
    type = BX_READ_64BIT_REG(i->dst());
  }
  else {
    type = BX_READ_32BIT_REG(i->dst());
  }

  BxPackedXmmRegister invvpid_desc;
  bx_address eaddr = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
  read_virtual_xmmword(i->seg(), eaddr, (Bit8u *) &invvpid_desc);

  if (invvpid_desc.xmm64u(0) > 0xffff) {
    BX_ERROR(("INVVPID: INVVPID_DESC reserved bits set"));
    VMfail(VMXERR_INVALID_INVEPT_INVVPID);
    BX_NEXT_TRACE(i);
  }

  Bit16u vpid = invvpid_desc.xmm16u(0);
  if (vpid == 0 && type != BX_INVEPT_INVVPID_ALL_CONTEXT_INVALIDATION) {
    BX_ERROR(("INVVPID with VPID=0"));
    VMfail(VMXERR_INVALID_INVEPT_INVVPID);
    BX_NEXT_TRACE(i);
  }

  switch(type) {
  case BX_INVEPT_INVVPID_INDIVIDUAL_ADDRESS_INVALIDATION:
    if (! IsCanonical(invvpid_desc.xmm64u(1))) {
      BX_ERROR(("INVVPID: non canonical LADDR single context invalidation"));
      VMfail(VMXERR_INVALID_INVEPT_INVVPID);
      BX_NEXT_TRACE(i);
    }

    TLB_flush(); // invalidate all mappings for address LADDR tagged with VPID
    break;

  case BX_INVEPT_INVVPID_SINGLE_CONTEXT_INVALIDATION:
    TLB_flush(); // invalidate all mappings tagged with VPID
    break;

  case BX_INVEPT_INVVPID_ALL_CONTEXT_INVALIDATION:
    TLB_flush(); // invalidate all mappings tagged with VPID <> 0
    break;
   
  case BX_INVEPT_INVVPID_SINGLE_CONTEXT_NON_GLOBAL_INVALIDATION:
    TLB_flushNonGlobal(); // invalidate all mappings tagged with VPID except globals
    break;

  default:
    BX_ERROR(("INVVPID: not supported type !"));
    VMfail(VMXERR_INVALID_INVEPT_INVVPID);
    BX_NEXT_TRACE(i);
  }

  BX_INSTR_TLB_CNTRL(BX_CPU_ID, BX_INSTR_INVVPID, type);

  VMsucceed();
#else
  BX_INFO(("INVVPID: required VMXx2 support, use --enable-vmx=2 option"));
  exception(BX_UD_EXCEPTION, 0);
#endif

  BX_NEXT_TRACE(i);
}

BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::INVPCID(bxInstruction_c *i)
{
  if (v8086_mode()) {
    BX_ERROR(("INVPCID: #GP - not recognized in v8086 mode"));
    exception(BX_GP_EXCEPTION, 0);
  }

#if BX_SUPPORT_VMX
  // INVPCID will always #UD in legacy VMX mode
  if (BX_CPU_THIS_PTR in_vmx_guest) {
    if (! SECONDARY_VMEXEC_CONTROL(VMX_VM_EXEC_CTRL3_INVPCID)) {
       BX_ERROR(("INVPCID in VMX guest: not allowed to use instruction !"));
       exception(BX_UD_EXCEPTION, 0);
    }

#if BX_SUPPORT_VMX >= 2
    if (VMEXIT(VMX_VM_EXEC_CTRL2_INVLPG_VMEXIT)) {
      VMexit_Instruction(i, VMX_VMEXIT_INVPCID, BX_READ);
    }
#endif

  }
#endif

  if (CPL != 0) {
    BX_ERROR(("INVPCID with CPL!=0 cause #GP(0)"));
    exception(BX_GP_EXCEPTION, 0);
  }

  bx_address type;
#if BX_SUPPORT_X86_64
  if (i->os64L()) {
    type = BX_READ_64BIT_REG(i->dst());
  }
  else
#endif
  {
    type = BX_READ_32BIT_REG(i->dst());
  }

  BxPackedXmmRegister invpcid_desc;
  bx_address eaddr = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
  read_virtual_xmmword(i->seg(), eaddr, (Bit8u *) &invpcid_desc);

  if (invpcid_desc.xmm64u(0) > 0xfff) {
    BX_ERROR(("INVPCID: INVPCID_DESC reserved bits set"));
    exception(BX_GP_EXCEPTION, 0);
  }

  Bit16u pcid = invpcid_desc.xmm16u(0) & 0xfff;

  switch(type) {
  case BX_INVPCID_INDIVIDUAL_ADDRESS_NON_GLOBAL_INVALIDATION:
#if BX_SUPPORT_X86_64
    if (! IsCanonical(invpcid_desc.xmm64u(1))) {
      BX_ERROR(("INVPCID: non canonical LADDR single context invalidation"));
      exception(BX_GP_EXCEPTION, 0);
    }
#endif
    if (! BX_CPU_THIS_PTR cr4.get_PCIDE() && pcid != 0) {
      BX_ERROR(("INVPCID: invalid PCID"));
      exception(BX_GP_EXCEPTION, 0);
    }
    TLB_flushNonGlobal(); // Invalidate all mappings for LADDR tagged with PCID except globals
    break;

  case BX_INVPCID_SINGLE_CONTEXT_NON_GLOBAL_INVALIDATION:
    if (! BX_CPU_THIS_PTR cr4.get_PCIDE() && pcid != 0) {
      BX_ERROR(("INVPCID: invalid PCID"));
      exception(BX_GP_EXCEPTION, 0);
    }
    TLB_flushNonGlobal(); // Invalidate all mappings tagged with PCID except globals
    break;

  case BX_INVPCID_ALL_CONTEXT_INVALIDATION:
    TLB_flush(); // Invalidate all mappings tagged with any PCID
    break;

  case BX_INVPCID_ALL_CONTEXT_NON_GLOBAL_INVALIDATION:
    TLB_flushNonGlobal(); // Invalidate all mappings tagged with any PCID except globals
    break;

  default:
    BX_ERROR(("INVPCID: not supported type !"));
    exception(BX_GP_EXCEPTION, 0);
  }

  BX_INSTR_TLB_CNTRL(BX_CPU_ID, BX_INSTR_INVPCID, type);

  BX_NEXT_TRACE(i);
}

#endif

BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::GETSEC(bxInstruction_c *i)
{
#if BX_CPU_LEVEL >= 6
  if (! BX_CPU_THIS_PTR cr4.get_SMXE())
    exception(BX_UD_EXCEPTION, 0);

#if BX_SUPPORT_VMX
  if (BX_CPU_THIS_PTR in_vmx_guest) {
    VMexit(VMX_VMEXIT_GETSEC, 0);
  }
#endif

  BX_PANIC(("GETSEC: SMX is not implemented yet !"));
#endif

  BX_NEXT_TRACE(i);
}

#if BX_SUPPORT_VMX
void BX_CPU_C::register_vmx_state(bx_param_c *parent)
{
  if (! bx_cpuid_support_vmx()) return;

  // register VMX state for save/restore param tree
  bx_list_c *vmx = new bx_list_c(parent, "VMX");

  BXRS_HEX_PARAM_FIELD(vmx, vmcsptr, BX_CPU_THIS_PTR vmcsptr);
  BXRS_HEX_PARAM_FIELD(vmx, vmxonptr, BX_CPU_THIS_PTR vmxonptr);
  BXRS_PARAM_BOOL(vmx, in_vmx, BX_CPU_THIS_PTR in_vmx);
  BXRS_PARAM_BOOL(vmx, in_vmx_guest, BX_CPU_THIS_PTR in_vmx_guest);
  BXRS_PARAM_BOOL(vmx, in_smm_vmx, BX_CPU_THIS_PTR in_smm_vmx);
  BXRS_PARAM_BOOL(vmx, in_smm_vmx_guest, BX_CPU_THIS_PTR in_smm_vmx_guest);

  bx_list_c *vmcache = new bx_list_c(vmx, "VMCS_CACHE");

  //
  // VM-Execution Control Fields
  //

  bx_list_c *vmexec_ctrls = new bx_list_c(vmcache, "VMEXEC_CTRLS");

  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vmexec_ctrls1, BX_CPU_THIS_PTR vmcs.vmexec_ctrls1);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vmexec_ctrls2, BX_CPU_THIS_PTR vmcs.vmexec_ctrls2);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vmexec_ctrls3, BX_CPU_THIS_PTR vmcs.vmexec_ctrls3);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vm_exceptions_bitmap, BX_CPU_THIS_PTR vmcs.vm_exceptions_bitmap);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vm_pf_mask, BX_CPU_THIS_PTR vmcs.vm_pf_mask);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vm_pf_match, BX_CPU_THIS_PTR vmcs.vm_pf_match);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, io_bitmap_addr1, BX_CPU_THIS_PTR vmcs.io_bitmap_addr[0]);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, io_bitmap_addr2, BX_CPU_THIS_PTR vmcs.io_bitmap_addr[1]);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, msr_bitmap_addr, BX_CPU_THIS_PTR vmcs.msr_bitmap_addr);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vm_cr0_mask, BX_CPU_THIS_PTR vmcs.vm_cr0_mask);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vm_cr0_read_shadow, BX_CPU_THIS_PTR vmcs.vm_cr0_read_shadow);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vm_cr4_mask, BX_CPU_THIS_PTR vmcs.vm_cr4_mask);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vm_cr4_read_shadow, BX_CPU_THIS_PTR vmcs.vm_cr4_read_shadow);
  BXRS_DEC_PARAM_FIELD(vmexec_ctrls, vm_cr3_target_cnt, BX_CPU_THIS_PTR vmcs.vm_cr3_target_cnt);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vm_cr3_target_value1, BX_CPU_THIS_PTR vmcs.vm_cr3_target_value[0]);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vm_cr3_target_value2, BX_CPU_THIS_PTR vmcs.vm_cr3_target_value[1]);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vm_cr3_target_value3, BX_CPU_THIS_PTR vmcs.vm_cr3_target_value[2]);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vm_cr3_target_value4, BX_CPU_THIS_PTR vmcs.vm_cr3_target_value[3]);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vmcs_linkptr, BX_CPU_THIS_PTR vmcs.vmcs_linkptr);
#if BX_SUPPORT_X86_64
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, virtual_apic_page_addr, BX_CPU_THIS_PTR vmcs.virtual_apic_page_addr);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vm_tpr_threshold, BX_CPU_THIS_PTR vmcs.vm_tpr_threshold);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, apic_access_page, BX_CPU_THIS_PTR vmcs.apic_access_page);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, apic_access, BX_CPU_THIS_PTR vmcs.apic_access);
#endif
#if BX_SUPPORT_VMX >= 2
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, eptptr, BX_CPU_THIS_PTR vmcs.eptptr);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vpid, BX_CPU_THIS_PTR vmcs.vpid);
#endif
#if BX_SUPPORT_VMX >= 2
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, pause_loop_exiting_gap, BX_CPU_THIS_PTR vmcs.ple.pause_loop_exiting_gap);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, pause_loop_exiting_window, BX_CPU_THIS_PTR vmcs.ple.pause_loop_exiting_window);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, first_pause_time, BX_CPU_THIS_PTR vmcs.ple.first_pause_time);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, last_pause_time, BX_CPU_THIS_PTR vmcs.ple.last_pause_time);
#endif
#if BX_SUPPORT_VMX >= 2
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, svi, BX_CPU_THIS_PTR vmcs.svi);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, rvi, BX_CPU_THIS_PTR vmcs.rvi);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vppr, BX_CPU_THIS_PTR vmcs.vppr);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, eoi_exit_bitmap0, BX_CPU_THIS_PTR vmcs.eoi_exit_bitmap[0]);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, eoi_exit_bitmap1, BX_CPU_THIS_PTR vmcs.eoi_exit_bitmap[1]);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, eoi_exit_bitmap2, BX_CPU_THIS_PTR vmcs.eoi_exit_bitmap[2]);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, eoi_exit_bitmap3, BX_CPU_THIS_PTR vmcs.eoi_exit_bitmap[3]);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, eoi_exit_bitmap4, BX_CPU_THIS_PTR vmcs.eoi_exit_bitmap[4]);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, eoi_exit_bitmap5, BX_CPU_THIS_PTR vmcs.eoi_exit_bitmap[5]);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, eoi_exit_bitmap6, BX_CPU_THIS_PTR vmcs.eoi_exit_bitmap[6]);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, eoi_exit_bitmap7, BX_CPU_THIS_PTR vmcs.eoi_exit_bitmap[7]);
#endif
#if BX_SUPPORT_VMX >= 2
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vmread_bitmap_addr, BX_CPU_THIS_PTR vmcs.vmread_bitmap_addr);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, vmwrite_bitmap_addr, BX_CPU_THIS_PTR vmcs.vmwrite_bitmap_addr);
#endif
#if BX_SUPPORT_VMX >= 2
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, ve_info_addr, BX_CPU_THIS_PTR vmcs.ve_info_addr);
  BXRS_HEX_PARAM_FIELD(vmexec_ctrls, eptp_index, BX_CPU_THIS_PTR vmcs.eptp_index);
#endif

  //
  // VM-Exit Control Fields
  //

  bx_list_c *vmexit_ctrls = new bx_list_c(vmcache, "VMEXIT_CTRLS");

  BXRS_HEX_PARAM_FIELD(vmexit_ctrls, vmexit_ctrls, BX_CPU_THIS_PTR vmcs.vmexit_ctrls);
  BXRS_DEC_PARAM_FIELD(vmexit_ctrls, vmexit_msr_store_cnt, BX_CPU_THIS_PTR vmcs.vmexit_msr_store_cnt);
  BXRS_HEX_PARAM_FIELD(vmexit_ctrls, vmexit_msr_store_addr, BX_CPU_THIS_PTR vmcs.vmexit_msr_store_addr);
  BXRS_DEC_PARAM_FIELD(vmexit_ctrls, vmexit_msr_load_cnt, BX_CPU_THIS_PTR vmcs.vmexit_msr_load_cnt);
  BXRS_HEX_PARAM_FIELD(vmexit_ctrls, vmexit_msr_load_addr, BX_CPU_THIS_PTR vmcs.vmexit_msr_load_addr);

  //
  // VM-Entry Control Fields
  //

  bx_list_c *vmentry_ctrls = new bx_list_c(vmcache, "VMENTRY_CTRLS");
   
  BXRS_HEX_PARAM_FIELD(vmentry_ctrls, vmentry_ctrls, BX_CPU_THIS_PTR vmcs.vmentry_ctrls);
  BXRS_DEC_PARAM_FIELD(vmentry_ctrls, vmentry_msr_load_cnt, BX_CPU_THIS_PTR vmcs.vmentry_msr_load_cnt);
  BXRS_HEX_PARAM_FIELD(vmentry_ctrls, vmentry_msr_load_addr, BX_CPU_THIS_PTR vmcs.vmentry_msr_load_addr);
  BXRS_HEX_PARAM_FIELD(vmentry_ctrls, vmentry_interr_info, BX_CPU_THIS_PTR vmcs.vmentry_interr_info);
  BXRS_HEX_PARAM_FIELD(vmentry_ctrls, vmentry_excep_err_code, BX_CPU_THIS_PTR vmcs.vmentry_excep_err_code);
  BXRS_HEX_PARAM_FIELD(vmentry_ctrls, vmentry_instr_length, BX_CPU_THIS_PTR vmcs.vmentry_instr_length);

  //
  // VMCS Host State
  //

  bx_list_c *host = new bx_list_c(vmcache, "HOST_STATE");

#undef NEED_CPU_REG_SHORTCUTS

  BXRS_HEX_PARAM_FIELD(host, CR0, BX_CPU_THIS_PTR vmcs.host_state.cr0);
  BXRS_HEX_PARAM_FIELD(host, CR3, BX_CPU_THIS_PTR vmcs.host_state.cr3);
  BXRS_HEX_PARAM_FIELD(host, CR4, BX_CPU_THIS_PTR vmcs.host_state.cr4);
  BXRS_HEX_PARAM_FIELD(host, ES, BX_CPU_THIS_PTR vmcs.host_state.segreg_selector[BX_SEG_REG_ES]);
  BXRS_HEX_PARAM_FIELD(host, CS, BX_CPU_THIS_PTR vmcs.host_state.segreg_selector[BX_SEG_REG_CS]);
  BXRS_HEX_PARAM_FIELD(host, SS, BX_CPU_THIS_PTR vmcs.host_state.segreg_selector[BX_SEG_REG_SS]);
  BXRS_HEX_PARAM_FIELD(host, DS, BX_CPU_THIS_PTR vmcs.host_state.segreg_selector[BX_SEG_REG_DS]);
  BXRS_HEX_PARAM_FIELD(host, FS, BX_CPU_THIS_PTR vmcs.host_state.segreg_selector[BX_SEG_REG_FS]);
  BXRS_HEX_PARAM_FIELD(host, FS_BASE, BX_CPU_THIS_PTR vmcs.host_state.fs_base);
  BXRS_HEX_PARAM_FIELD(host, GS, BX_CPU_THIS_PTR vmcs.host_state.segreg_selector[BX_SEG_REG_GS]);
  BXRS_HEX_PARAM_FIELD(host, GS_BASE, BX_CPU_THIS_PTR vmcs.host_state.gs_base);
  BXRS_HEX_PARAM_FIELD(host, GDTR_BASE, BX_CPU_THIS_PTR vmcs.host_state.gdtr_base);
  BXRS_HEX_PARAM_FIELD(host, IDTR_BASE, BX_CPU_THIS_PTR vmcs.host_state.idtr_base);
  BXRS_HEX_PARAM_FIELD(host, TR, BX_CPU_THIS_PTR vmcs.host_state.tr_selector);
  BXRS_HEX_PARAM_FIELD(host, TR_BASE, BX_CPU_THIS_PTR vmcs.host_state.tr_base);
  BXRS_HEX_PARAM_FIELD(host, RSP, BX_CPU_THIS_PTR vmcs.host_state.rsp);
  BXRS_HEX_PARAM_FIELD(host, RIP, BX_CPU_THIS_PTR vmcs.host_state.rip);
  BXRS_HEX_PARAM_FIELD(host, sysenter_esp_msr, BX_CPU_THIS_PTR vmcs.host_state.sysenter_esp_msr);
  BXRS_HEX_PARAM_FIELD(host, sysenter_eip_msr, BX_CPU_THIS_PTR vmcs.host_state.sysenter_eip_msr);
  BXRS_HEX_PARAM_FIELD(host, sysenter_cs_msr, BX_CPU_THIS_PTR vmcs.host_state.sysenter_cs_msr);
#if BX_SUPPORT_VMX >= 2
  BXRS_HEX_PARAM_FIELD(host, pat_msr, BX_CPU_THIS_PTR vmcs.host_state.pat_msr);
#if BX_SUPPORT_X86_64
  BXRS_HEX_PARAM_FIELD(host, efer_msr, BX_CPU_THIS_PTR vmcs.host_state.efer_msr);
#endif
#endif
}

#endif // BX_SUPPORT_VMX