// Interrupt
_Use_decl_annotations_ static void VmmpHandleException(
GuestContext *guest_context) {
HYPERPLATFORM_PERFORMANCE_MEASURE_THIS_SCOPE();
const VmExitInterruptionInformationField exception = {
static_cast<ULONG32>(UtilVmRead(VmcsField::kVmExitIntrInfo))};
if (static_cast<interruption_type>(exception.fields.interruption_type) ==
interruption_type::kHardwareException) {
// Hardware exception
if (static_cast<InterruptionVector>(exception.fields.vector) ==
InterruptionVector::kPageFaultException) {
// #PF
const PageFaultErrorCode fault_code = {
static_cast<ULONG32>(UtilVmRead(VmcsField::kVmExitIntrErrorCode))};
const auto fault_address = UtilVmRead(VmcsField::kExitQualification);
VmEntryInterruptionInformationField inject = {};
inject.fields.interruption_type = exception.fields.interruption_type;
inject.fields.vector = exception.fields.vector;
inject.fields.deliver_error_code = true;
inject.fields.valid = true;
AsmWriteCR2(fault_address);
UtilVmWrite(VmcsField::kVmEntryExceptionErrorCode, fault_code.all);
UtilVmWrite(VmcsField::kVmEntryIntrInfoField, inject.all);
HYPERPLATFORM_LOG_INFO_SAFE("GuestIp= %p, #PF Fault= %p Code= 0x%2x",
guest_context->ip, fault_address, fault_code);
} else if (static_cast<InterruptionVector>(exception.fields.vector) ==
InterruptionVector::kGeneralProtectionException) {
// # GP
const auto error_code =
static_cast<ULONG32>(UtilVmRead(VmcsField::kVmExitIntrErrorCode));
VmEntryInterruptionInformationField inject = {};
inject.fields.interruption_type = exception.fields.interruption_type;
inject.fields.vector = exception.fields.vector;
inject.fields.deliver_error_code = true;
inject.fields.valid = true;
UtilVmWrite(VmcsField::kVmEntryExceptionErrorCode, error_code);
UtilVmWrite(VmcsField::kVmEntryIntrInfoField, inject.all);
HYPERPLATFORM_LOG_INFO_SAFE("GuestIp= %p, #GP Code= 0x%2x",
guest_context->ip, error_code);
} else {
HYPERPLATFORM_COMMON_BUG_CHECK(HyperPlatformBugCheck::kUnspecified, 0, 0,
0);
}
} else if (static_cast<interruption_type>(
exception.fields.interruption_type) ==
interruption_type::kSoftwareException) {
// Software exception
if (static_cast<InterruptionVector>(exception.fields.vector) ==
InterruptionVector::kBreakpointException) {
// #BP
VmEntryInterruptionInformationField inject = {};
inject.fields.interruption_type = exception.fields.interruption_type;
inject.fields.vector = exception.fields.vector;
inject.fields.deliver_error_code = false;
inject.fields.valid = true;
UtilVmWrite(VmcsField::kVmEntryIntrInfoField, inject.all);
UtilVmWrite(VmcsField::kVmEntryInstructionLen, 1);
HYPERPLATFORM_LOG_INFO_SAFE("GuestIp= %p, #BP ", guest_context->ip);
} else {
HYPERPLATFORM_COMMON_BUG_CHECK(HyperPlatformBugCheck::kUnspecified, 0, 0,
0);
}
} else {
HYPERPLATFORM_COMMON_BUG_CHECK(HyperPlatformBugCheck::kUnspecified, 0, 0,
0);
}
}
// Sets rip to the next instruction
_Use_decl_annotations_ static void VmmpAdjustGuestInstructionPointer(
ULONG_PTR guest_ip) {
const auto exit_instruction_length =
UtilVmRead(VmcsField::kVmExitInstructionLen);
UtilVmWrite(VmcsField::kGuestRip, guest_ip + exit_instruction_length);
}
// See: PREPARATION AND LAUNCHING A VIRTUAL MACHINE
_Use_decl_annotations_ static bool VmpSetupVmcs(
const ProcessorData *processor_data, ULONG_PTR guest_stack_pointer,
ULONG_PTR guest_instruction_pointer, ULONG_PTR vmm_stack_pointer) {
PAGED_CODE();
Gdtr gdtr = {};
__sgdt(&gdtr);
Idtr idtr = {};
__sidt(&idtr);
// See: Algorithms for Determining VMX Capabilities
const auto use_true_msrs = Ia32VmxBasicMsr{
UtilReadMsr64(
Msr::kIa32VmxBasic)}.fields.vmx_capability_hint;
VmxVmEntryControls vm_entryctl_requested = {};
vm_entryctl_requested.fields.load_debug_controls = true;
vm_entryctl_requested.fields.ia32e_mode_guest = IsX64();
VmxVmEntryControls vm_entryctl = {VmpAdjustControlValue(
(use_true_msrs) ? Msr::kIa32VmxTrueEntryCtls : Msr::kIa32VmxEntryCtls,
vm_entryctl_requested.all)};
VmxVmExitControls vm_exitctl_requested = {};
vm_exitctl_requested.fields.host_address_space_size = IsX64();
vm_exitctl_requested.fields.acknowledge_interrupt_on_exit = true;
VmxVmExitControls vm_exitctl = {VmpAdjustControlValue(
(use_true_msrs) ? Msr::kIa32VmxTrueExitCtls : Msr::kIa32VmxExitCtls,
vm_exitctl_requested.all)};
VmxPinBasedControls vm_pinctl_requested = {};
VmxPinBasedControls vm_pinctl = {
VmpAdjustControlValue((use_true_msrs) ? Msr::kIa32VmxTruePinbasedCtls
: Msr::kIa32VmxPinbasedCtls,
vm_pinctl_requested.all)};
VmxProcessorBasedControls vm_procctl_requested = {};
vm_procctl_requested.fields.invlpg_exiting = false;
vm_procctl_requested.fields.rdtsc_exiting = false;
vm_procctl_requested.fields.cr3_load_exiting = true;
vm_procctl_requested.fields.cr8_load_exiting = false; // NB: very frequent
vm_procctl_requested.fields.mov_dr_exiting = true;
vm_procctl_requested.fields.use_io_bitmaps = true;
vm_procctl_requested.fields.use_msr_bitmaps = true;
vm_procctl_requested.fields.activate_secondary_control = true;
VmxProcessorBasedControls vm_procctl = {
VmpAdjustControlValue((use_true_msrs) ? Msr::kIa32VmxTrueProcBasedCtls
: Msr::kIa32VmxProcBasedCtls,
vm_procctl_requested.all)};
VmxSecondaryProcessorBasedControls vm_procctl2_requested = {};
vm_procctl2_requested.fields.enable_ept = true;
vm_procctl2_requested.fields.descriptor_table_exiting = true;
vm_procctl2_requested.fields.enable_rdtscp = true; // for Win10
vm_procctl2_requested.fields.enable_vpid = true;
vm_procctl2_requested.fields.enable_xsaves_xstors = true; // for Win10
VmxSecondaryProcessorBasedControls vm_procctl2 = {VmpAdjustControlValue(
Msr::kIa32VmxProcBasedCtls2, vm_procctl2_requested.all)};
// NOTE: Comment in any of those as needed
const auto exception_bitmap =
// 1 << InterruptionVector::kBreakpointException |
// 1 << InterruptionVector::kGeneralProtectionException |
// 1 << InterruptionVector::kPageFaultException |
0;
// Set up CR0 and CR4 bitmaps
// - Where a bit is masked, the shadow bit appears
// - Where a bit is not masked, the actual bit appears
// VM-exit occurs when a guest modifies any of those fields
Cr0 cr0_mask = {};
Cr0 cr0_shadow = {__readcr0()};
Cr4 cr4_mask = {};
Cr4 cr4_shadow = {__readcr4()};
// For example, when we want to hide CR4.VMXE from the guest, comment in below
// cr4_mask.fields.vmxe = true;
// cr4_shadow.fields.vmxe = false;
// See: PDPTE Registers
// If PAE paging would be in use following an execution of MOV to CR0 or MOV
// to CR4 (see Section 4.1.1) and the instruction is modifying any of CR0.CD,
// CR0.NW, CR0.PG, CR4.PAE, CR4.PGE, CR4.PSE, or CR4.SMEP; then the PDPTEs are
// loaded from the address in CR3.
if (UtilIsX86Pae()) {
cr0_mask.fields.pg = true;
cr0_mask.fields.cd = true;
cr0_mask.fields.nw = true;
cr4_mask.fields.pae = true;
cr4_mask.fields.pge = true;
cr4_mask.fields.pse = true;
cr4_mask.fields.smep = true;
}
// clang-format off
auto error = VmxStatus::kOk;
/* 16-Bit Control Field */
error |= UtilVmWrite(VmcsField::kVirtualProcessorId, KeGetCurrentProcessorNumberEx(nullptr) + 1);
/* 16-Bit Guest-State Fields */
error |= UtilVmWrite(VmcsField::kGuestEsSelector, AsmReadES());
error |= UtilVmWrite(VmcsField::kGuestCsSelector, AsmReadCS());
error |= UtilVmWrite(VmcsField::kGuestSsSelector, AsmReadSS());
error |= UtilVmWrite(VmcsField::kGuestDsSelector, AsmReadDS());
error |= UtilVmWrite(VmcsField::kGuestFsSelector, AsmReadFS());
error |= UtilVmWrite(VmcsField::kGuestGsSelector, AsmReadGS());
error |= UtilVmWrite(VmcsField::kGuestLdtrSelector, AsmReadLDTR());
error |= UtilVmWrite(VmcsField::kGuestTrSelector, AsmReadTR());
/* 16-Bit Host-State Fields */
// RPL and TI have to be 0
error |= UtilVmWrite(VmcsField::kHostEsSelector, AsmReadES() & 0xf8);
error |= UtilVmWrite(VmcsField::kHostCsSelector, AsmReadCS() & 0xf8);
error |= UtilVmWrite(VmcsField::kHostSsSelector, AsmReadSS() & 0xf8);
error |= UtilVmWrite(VmcsField::kHostDsSelector, AsmReadDS() & 0xf8);
error |= UtilVmWrite(VmcsField::kHostFsSelector, AsmReadFS() & 0xf8);
error |= UtilVmWrite(VmcsField::kHostGsSelector, AsmReadGS() & 0xf8);
error |= UtilVmWrite(VmcsField::kHostTrSelector, AsmReadTR() & 0xf8);
/* 64-Bit Control Fields */
error |= UtilVmWrite64(VmcsField::kIoBitmapA, UtilPaFromVa(processor_data->shared_data->io_bitmap_a));
error |= UtilVmWrite64(VmcsField::kIoBitmapB, UtilPaFromVa(processor_data->shared_data->io_bitmap_b));
error |= UtilVmWrite64(VmcsField::kMsrBitmap, UtilPaFromVa(processor_data->shared_data->msr_bitmap));
error |= UtilVmWrite64(VmcsField::kEptPointer, EptGetEptPointer(processor_data->ept_data));
/* 64-Bit Guest-State Fields */
error |= UtilVmWrite64(VmcsField::kVmcsLinkPointer, MAXULONG64);
error |= UtilVmWrite64(VmcsField::kGuestIa32Debugctl, UtilReadMsr64(Msr::kIa32Debugctl));
if (UtilIsX86Pae()) {
UtilLoadPdptes(__readcr3());
}
/* 32-Bit Control Fields */
error |= UtilVmWrite(VmcsField::kPinBasedVmExecControl, vm_pinctl.all);
error |= UtilVmWrite(VmcsField::kCpuBasedVmExecControl, vm_procctl.all);
error |= UtilVmWrite(VmcsField::kExceptionBitmap, exception_bitmap);
error |= UtilVmWrite(VmcsField::kVmExitControls, vm_exitctl.all);
error |= UtilVmWrite(VmcsField::kVmEntryControls, vm_entryctl.all);
error |= UtilVmWrite(VmcsField::kSecondaryVmExecControl, vm_procctl2.all);
/* 32-Bit Guest-State Fields */
error |= UtilVmWrite(VmcsField::kGuestEsLimit, GetSegmentLimit(AsmReadES()));
error |= UtilVmWrite(VmcsField::kGuestCsLimit, GetSegmentLimit(AsmReadCS()));
error |= UtilVmWrite(VmcsField::kGuestSsLimit, GetSegmentLimit(AsmReadSS()));
error |= UtilVmWrite(VmcsField::kGuestDsLimit, GetSegmentLimit(AsmReadDS()));
error |= UtilVmWrite(VmcsField::kGuestFsLimit, GetSegmentLimit(AsmReadFS()));
error |= UtilVmWrite(VmcsField::kGuestGsLimit, GetSegmentLimit(AsmReadGS()));
error |= UtilVmWrite(VmcsField::kGuestLdtrLimit, GetSegmentLimit(AsmReadLDTR()));
error |= UtilVmWrite(VmcsField::kGuestTrLimit, GetSegmentLimit(AsmReadTR()));
error |= UtilVmWrite(VmcsField::kGuestGdtrLimit, gdtr.limit);
error |= UtilVmWrite(VmcsField::kGuestIdtrLimit, idtr.limit);
error |= UtilVmWrite(VmcsField::kGuestEsArBytes, VmpGetSegmentAccessRight(AsmReadES()));
error |= UtilVmWrite(VmcsField::kGuestCsArBytes, VmpGetSegmentAccessRight(AsmReadCS()));
error |= UtilVmWrite(VmcsField::kGuestSsArBytes, VmpGetSegmentAccessRight(AsmReadSS()));
error |= UtilVmWrite(VmcsField::kGuestDsArBytes, VmpGetSegmentAccessRight(AsmReadDS()));
error |= UtilVmWrite(VmcsField::kGuestFsArBytes, VmpGetSegmentAccessRight(AsmReadFS()));
error |= UtilVmWrite(VmcsField::kGuestGsArBytes, VmpGetSegmentAccessRight(AsmReadGS()));
error |= UtilVmWrite(VmcsField::kGuestLdtrArBytes, VmpGetSegmentAccessRight(AsmReadLDTR()));
error |= UtilVmWrite(VmcsField::kGuestTrArBytes, VmpGetSegmentAccessRight(AsmReadTR()));
error |= UtilVmWrite(VmcsField::kGuestSysenterCs, UtilReadMsr(Msr::kIa32SysenterCs));
/* 32-Bit Host-State Field */
error |= UtilVmWrite(VmcsField::kHostIa32SysenterCs, UtilReadMsr(Msr::kIa32SysenterCs));
/* Natural-Width Control Fields */
error |= UtilVmWrite(VmcsField::kCr0GuestHostMask, cr0_mask.all);
error |= UtilVmWrite(VmcsField::kCr4GuestHostMask, cr4_mask.all);
error |= UtilVmWrite(VmcsField::kCr0ReadShadow, cr0_shadow.all);
error |= UtilVmWrite(VmcsField::kCr4ReadShadow, cr4_shadow.all);
/* Natural-Width Guest-State Fields */
error |= UtilVmWrite(VmcsField::kGuestCr0, __readcr0());
error |= UtilVmWrite(VmcsField::kGuestCr3, __readcr3());
error |= UtilVmWrite(VmcsField::kGuestCr4, __readcr4());
#if defined(_AMD64_)
error |= UtilVmWrite(VmcsField::kGuestEsBase, 0);
error |= UtilVmWrite(VmcsField::kGuestCsBase, 0);
error |= UtilVmWrite(VmcsField::kGuestSsBase, 0);
error |= UtilVmWrite(VmcsField::kGuestDsBase, 0);
error |= UtilVmWrite(VmcsField::kGuestFsBase, UtilReadMsr(Msr::kIa32FsBase));
error |= UtilVmWrite(VmcsField::kGuestGsBase, UtilReadMsr(Msr::kIa32GsBase));
#else
error |= UtilVmWrite(VmcsField::kGuestEsBase, VmpGetSegmentBase(gdtr.base, AsmReadES()));
error |= UtilVmWrite(VmcsField::kGuestCsBase, VmpGetSegmentBase(gdtr.base, AsmReadCS()));
error |= UtilVmWrite(VmcsField::kGuestSsBase, VmpGetSegmentBase(gdtr.base, AsmReadSS()));
error |= UtilVmWrite(VmcsField::kGuestDsBase, VmpGetSegmentBase(gdtr.base, AsmReadDS()));
error |= UtilVmWrite(VmcsField::kGuestFsBase, VmpGetSegmentBase(gdtr.base, AsmReadFS()));
error |= UtilVmWrite(VmcsField::kGuestGsBase, VmpGetSegmentBase(gdtr.base, AsmReadGS()));
#endif
error |= UtilVmWrite(VmcsField::kGuestLdtrBase, VmpGetSegmentBase(gdtr.base, AsmReadLDTR()));
error |= UtilVmWrite(VmcsField::kGuestTrBase, VmpGetSegmentBase(gdtr.base, AsmReadTR()));
error |= UtilVmWrite(VmcsField::kGuestGdtrBase, gdtr.base);
error |= UtilVmWrite(VmcsField::kGuestIdtrBase, idtr.base);
error |= UtilVmWrite(VmcsField::kGuestDr7, __readdr(7));
error |= UtilVmWrite(VmcsField::kGuestRsp, guest_stack_pointer);
error |= UtilVmWrite(VmcsField::kGuestRip, guest_instruction_pointer);
error |= UtilVmWrite(VmcsField::kGuestRflags, __readeflags());
error |= UtilVmWrite(VmcsField::kGuestSysenterEsp, UtilReadMsr(Msr::kIa32SysenterEsp));
error |= UtilVmWrite(VmcsField::kGuestSysenterEip, UtilReadMsr(Msr::kIa32SysenterEip));
/* Natural-Width Host-State Fields */
error |= UtilVmWrite(VmcsField::kHostCr0, __readcr0());
error |= UtilVmWrite(VmcsField::kHostCr3, __readcr3());
error |= UtilVmWrite(VmcsField::kHostCr4, __readcr4());
#if defined(_AMD64_)
error |= UtilVmWrite(VmcsField::kHostFsBase, UtilReadMsr(Msr::kIa32FsBase));
error |= UtilVmWrite(VmcsField::kHostGsBase, UtilReadMsr(Msr::kIa32GsBase));
#else
error |= UtilVmWrite(VmcsField::kHostFsBase, VmpGetSegmentBase(gdtr.base, AsmReadFS()));
error |= UtilVmWrite(VmcsField::kHostGsBase, VmpGetSegmentBase(gdtr.base, AsmReadGS()));
#endif
error |= UtilVmWrite(VmcsField::kHostTrBase, VmpGetSegmentBase(gdtr.base, AsmReadTR()));
error |= UtilVmWrite(VmcsField::kHostGdtrBase, gdtr.base);
error |= UtilVmWrite(VmcsField::kHostIdtrBase, idtr.base);
error |= UtilVmWrite(VmcsField::kHostIa32SysenterEsp, UtilReadMsr(Msr::kIa32SysenterEsp));
error |= UtilVmWrite(VmcsField::kHostIa32SysenterEip, UtilReadMsr(Msr::kIa32SysenterEip));
error |= UtilVmWrite(VmcsField::kHostRsp, vmm_stack_pointer);
error |= UtilVmWrite(VmcsField::kHostRip, reinterpret_cast<ULONG_PTR>(AsmVmmEntryPoint));
// clang-format on
const auto vmx_status = static_cast<VmxStatus>(error);
return vmx_status == VmxStatus::kOk;
}
// MOV to / from CRx
_Use_decl_annotations_ static void VmmpHandleCrAccess(
GuestContext *guest_context) {
HYPERPLATFORM_PERFORMANCE_MEASURE_THIS_SCOPE();
const MovCrQualification exit_qualification = {
UtilVmRead(VmcsField::kExitQualification)};
const auto register_used =
VmmpSelectRegister(exit_qualification.fields.gp_register, guest_context);
switch (static_cast<MovCrAccessType>(exit_qualification.fields.access_type)) {
case MovCrAccessType::kMoveToCr:
switch (exit_qualification.fields.control_register) {
// CR0 <- Reg
case 0: {
HYPERPLATFORM_PERFORMANCE_MEASURE_THIS_SCOPE();
if (UtilIsX86Pae()) {
UtilLoadPdptes(UtilVmRead(VmcsField::kGuestCr3));
}
UtilVmWrite(VmcsField::kGuestCr0, *register_used);
UtilVmWrite(VmcsField::kCr0ReadShadow, *register_used);
break;
}
// CR3 <- Reg
case 3: {
HYPERPLATFORM_PERFORMANCE_MEASURE_THIS_SCOPE();
if (UtilIsX86Pae()) {
UtilLoadPdptes(*register_used);
}
UtilVmWrite(VmcsField::kGuestCr3, *register_used);
break;
}
// CR4 <- Reg
case 4: {
HYPERPLATFORM_PERFORMANCE_MEASURE_THIS_SCOPE();
if (UtilIsX86Pae()) {
UtilLoadPdptes(UtilVmRead(VmcsField::kGuestCr3));
}
UtilVmWrite(VmcsField::kGuestCr4, *register_used);
UtilVmWrite(VmcsField::kCr4ReadShadow, *register_used);
break;
}
// CR8 <- Reg
case 8: {
HYPERPLATFORM_PERFORMANCE_MEASURE_THIS_SCOPE();
guest_context->cr8 = *register_used;
break;
}
default:
HYPERPLATFORM_COMMON_BUG_CHECK(HyperPlatformBugCheck::kUnspecified, 0,
0, 0);
break;
}
break;
case MovCrAccessType::kMoveFromCr:
switch (exit_qualification.fields.control_register) {
// Reg <- CR3
case 3: {
HYPERPLATFORM_PERFORMANCE_MEASURE_THIS_SCOPE();
*register_used = UtilVmRead(VmcsField::kGuestCr3);
break;
}
// Reg <- CR8
case 8: {
HYPERPLATFORM_PERFORMANCE_MEASURE_THIS_SCOPE();
*register_used = guest_context->cr8;
break;
}
default:
HYPERPLATFORM_COMMON_BUG_CHECK(HyperPlatformBugCheck::kUnspecified, 0,
0, 0);
break;
}
break;
// Unimplemented
case MovCrAccessType::kClts:
case MovCrAccessType::kLmsw:
default:
HYPERPLATFORM_COMMON_DBG_BREAK();
break;
}
VmmpAdjustGuestInstructionPointer(guest_context->ip);
}
// LLDT, LTR, SLDT, and STR
_Use_decl_annotations_ static void VmmpHandleLdtrOrTrAccess(
GuestContext *guest_context) {
HYPERPLATFORM_PERFORMANCE_MEASURE_THIS_SCOPE();
const LdtrOrTrInstInformation exit_qualification = {
static_cast<ULONG32>(UtilVmRead(VmcsField::kVmxInstructionInfo))};
// Calculate an address or a register to be used for the instruction
const auto displacement = UtilVmRead(VmcsField::kExitQualification);
ULONG_PTR operation_address = 0;
if (exit_qualification.fields.register_access) {
// Register
const auto register_used =
VmmpSelectRegister(exit_qualification.fields.register1, guest_context);
operation_address = reinterpret_cast<ULONG_PTR>(register_used);
} else {
// Base
ULONG_PTR base_value = 0;
if (!exit_qualification.fields.base_register_invalid) {
const auto register_used = VmmpSelectRegister(
exit_qualification.fields.base_register, guest_context);
base_value = *register_used;
}
// Index
ULONG_PTR index_value = 0;
if (!exit_qualification.fields.index_register_invalid) {
const auto register_used = VmmpSelectRegister(
exit_qualification.fields.index_register, guest_context);
index_value = *register_used;
switch (static_cast<Scaling>(exit_qualification.fields.scalling)) {
case Scaling::kNoScaling:
index_value = index_value;
break;
case Scaling::kScaleBy2:
index_value = index_value * 2;
break;
case Scaling::kScaleBy4:
index_value = index_value * 4;
break;
case Scaling::kScaleBy8:
index_value = index_value * 8;
break;
default:
break;
}
}
operation_address = base_value + index_value + displacement;
if (static_cast<AddressSize>(exit_qualification.fields.address_size) ==
AddressSize::k32bit) {
operation_address &= MAXULONG;
}
}
// Update CR3 with that of the guest since below code is going to access
// memory.
const auto guest_cr3 = UtilVmRead(VmcsField::kGuestCr3);
const auto vmm_cr3 = __readcr3();
__writecr3(guest_cr3);
// Emulate the instruction
auto selector = reinterpret_cast<USHORT *>(operation_address);
switch (static_cast<LdtrOrTrInstructionIdentity>(
exit_qualification.fields.instruction_identity)) {
case LdtrOrTrInstructionIdentity::kSldt:
*selector =
static_cast<USHORT>(UtilVmRead(VmcsField::kGuestLdtrSelector));
break;
case LdtrOrTrInstructionIdentity::kStr:
*selector = static_cast<USHORT>(UtilVmRead(VmcsField::kGuestTrSelector));
break;
case LdtrOrTrInstructionIdentity::kLldt:
UtilVmWrite(VmcsField::kGuestLdtrSelector, *selector);
break;
case LdtrOrTrInstructionIdentity::kLtr:
UtilVmWrite(VmcsField::kGuestTrSelector, *selector);
break;
}
__writecr3(vmm_cr3);
VmmpAdjustGuestInstructionPointer(guest_context->ip);
}
// LIDT, SIDT, LGDT and SGDT
_Use_decl_annotations_ static void VmmpHandleGdtrOrIdtrAccess(
GuestContext *guest_context) {
HYPERPLATFORM_PERFORMANCE_MEASURE_THIS_SCOPE();
const GdtrOrIdtrInstInformation exit_qualification = {
static_cast<ULONG32>(UtilVmRead(VmcsField::kVmxInstructionInfo))};
// Calculate an address to be used for the instruction
const auto displacement = UtilVmRead(VmcsField::kExitQualification);
// Base
ULONG_PTR base_value = 0;
if (!exit_qualification.fields.base_register_invalid) {
const auto register_used = VmmpSelectRegister(
exit_qualification.fields.base_register, guest_context);
base_value = *register_used;
}
// Index
ULONG_PTR index_value = 0;
if (!exit_qualification.fields.index_register_invalid) {
const auto register_used = VmmpSelectRegister(
exit_qualification.fields.index_register, guest_context);
index_value = *register_used;
switch (static_cast<Scaling>(exit_qualification.fields.scalling)) {
case Scaling::kNoScaling:
index_value = index_value;
break;
case Scaling::kScaleBy2:
index_value = index_value * 2;
break;
case Scaling::kScaleBy4:
index_value = index_value * 4;
break;
case Scaling::kScaleBy8:
index_value = index_value * 8;
break;
default:
break;
}
}
auto operation_address = base_value + index_value + displacement;
if (static_cast<AddressSize>(exit_qualification.fields.address_size) ==
AddressSize::k32bit) {
operation_address &= MAXULONG;
}
// Update CR3 with that of the guest since below code is going to access
// memory.
const auto guest_cr3 = UtilVmRead(VmcsField::kGuestCr3);
const auto vmm_cr3 = __readcr3();
__writecr3(guest_cr3);
// Emulate the instruction
auto descriptor_table_reg = reinterpret_cast<Idtr *>(operation_address);
switch (static_cast<GdtrOrIdtrInstructionIdentity>(
exit_qualification.fields.instruction_identity)) {
case GdtrOrIdtrInstructionIdentity::kSgdt:
descriptor_table_reg->base = UtilVmRead(VmcsField::kGuestGdtrBase);
descriptor_table_reg->limit =
static_cast<unsigned short>(UtilVmRead(VmcsField::kGuestGdtrLimit));
break;
case GdtrOrIdtrInstructionIdentity::kSidt:
descriptor_table_reg->base = UtilVmRead(VmcsField::kGuestIdtrBase);
descriptor_table_reg->limit =
static_cast<unsigned short>(UtilVmRead(VmcsField::kGuestIdtrLimit));
break;
case GdtrOrIdtrInstructionIdentity::kLgdt:
UtilVmWrite(VmcsField::kGuestGdtrBase, descriptor_table_reg->base);
UtilVmWrite(VmcsField::kGuestGdtrLimit, descriptor_table_reg->limit);
break;
case GdtrOrIdtrInstructionIdentity::kLidt:
UtilVmWrite(VmcsField::kGuestIdtrBase, descriptor_table_reg->base);
UtilVmWrite(VmcsField::kGuestIdtrLimit, descriptor_table_reg->limit);
break;
}
__writecr3(vmm_cr3);
VmmpAdjustGuestInstructionPointer(guest_context->ip);
}