// See: VMM SETUP & TEAR DOWN
_Use_decl_annotations_ static bool VmpEnterVmxMode(
ProcessorData *processor_data) {
// Apply FIXED bits
const Cr0 cr0_fixed0 = {UtilReadMsr(Msr::kIa32VmxCr0Fixed0)};
const Cr0 cr0_fixed1 = {UtilReadMsr(Msr::kIa32VmxCr0Fixed1)};
Cr0 cr0 = {__readcr0()};
cr0.all &= cr0_fixed1.all;
cr0.all |= cr0_fixed0.all;
__writecr0(cr0.all);
const Cr4 cr4_fixed0 = {UtilReadMsr(Msr::kIa32VmxCr4Fixed0)};
const Cr4 cr4_fixed1 = {UtilReadMsr(Msr::kIa32VmxCr4Fixed1)};
Cr4 cr4 = {__readcr4()};
cr4.all &= cr4_fixed1.all;
cr4.all |= cr4_fixed0.all;
__writecr4(cr4.all);
// Write a VMCS revision identifier
const Ia32VmxBasicMsr vmx_basic_msr = {UtilReadMsr64(Msr::kIa32VmxBasic)};
processor_data->vmxon_region->revision_identifier =
vmx_basic_msr.fields.revision_identifier;
auto vmxon_region_pa = UtilPaFromVa(processor_data->vmxon_region);
if (__vmx_on(&vmxon_region_pa)) {
return false;
}
UtilInveptAll();
return true;
}
// See: VMM SETUP & TEAR DOWN
_Use_decl_annotations_ static bool VmpEnterVmxMode(
ProcessorData *processor_data) {
PAGED_CODE();
// Apply FIXED bits
// See: VMX-FIXED BITS IN CR0
// IA32_VMX_CRx_FIXED0 IA32_VMX_CRx_FIXED1 Meaning
// Values 1 1 bit of CRx is fixed to 1
// Values 0 1 bit of CRx is flexible
// Values 0 0 bit of CRx is fixed to 0
const Cr0 cr0_fixed0 = {UtilReadMsr(Msr::kIa32VmxCr0Fixed0)};
const Cr0 cr0_fixed1 = {UtilReadMsr(Msr::kIa32VmxCr0Fixed1)};
Cr0 cr0 = {__readcr0()};
Cr0 cr0_original = cr0;
cr0.all &= cr0_fixed1.all;
cr0.all |= cr0_fixed0.all;
__writecr0(cr0.all);
HYPERPLATFORM_LOG_DEBUG("IA32_VMX_CR0_FIXED0 = %08x", cr0_fixed0.all);
HYPERPLATFORM_LOG_DEBUG("IA32_VMX_CR0_FIXED1 = %08x", cr0_fixed1.all);
HYPERPLATFORM_LOG_DEBUG("Original CR0 = %08x", cr0_original.all);
HYPERPLATFORM_LOG_DEBUG("Fixed CR0 = %08x", cr0.all);
// See: VMX-FIXED BITS IN CR4
const Cr4 cr4_fixed0 = {UtilReadMsr(Msr::kIa32VmxCr4Fixed0)};
const Cr4 cr4_fixed1 = {UtilReadMsr(Msr::kIa32VmxCr4Fixed1)};
Cr4 cr4 = {__readcr4()};
Cr4 cr4_original = cr4;
cr4.all &= cr4_fixed1.all;
cr4.all |= cr4_fixed0.all;
__writecr4(cr4.all);
HYPERPLATFORM_LOG_DEBUG("IA32_VMX_CR4_FIXED0 = %08x", cr4_fixed0.all);
HYPERPLATFORM_LOG_DEBUG("IA32_VMX_CR4_FIXED1 = %08x", cr4_fixed1.all);
HYPERPLATFORM_LOG_DEBUG("Original CR4 = %08x", cr4_original.all);
HYPERPLATFORM_LOG_DEBUG("Fixed CR4 = %08x", cr4.all);
// Write a VMCS revision identifier
const Ia32VmxBasicMsr vmx_basic_msr = {UtilReadMsr64(Msr::kIa32VmxBasic)};
processor_data->vmxon_region->revision_identifier =
vmx_basic_msr.fields.revision_identifier;
auto vmxon_region_pa = UtilPaFromVa(processor_data->vmxon_region);
if (__vmx_on(&vmxon_region_pa)) {
return false;
}
// See: Guidelines for Use of the INVVPID Instruction, and Guidelines for Use
// of the INVEPT Instruction
UtilInveptGlobal();
UtilInvvpidAllContext();
return true;
}
// Initialize shared processor data
_Use_decl_annotations_ static SharedProcessorData *VmpInitializeSharedData() {
PAGED_CODE();
const auto shared_data = reinterpret_cast<SharedProcessorData *>(
ExAllocatePoolWithTag(NonPagedPoolNx, sizeof(SharedProcessorData),
kHyperPlatformCommonPoolTag));
if (!shared_data) {
return nullptr;
}
RtlZeroMemory(shared_data, sizeof(SharedProcessorData));
HYPERPLATFORM_LOG_DEBUG("SharedData= %p", shared_data);
// Set up the MSR bitmap
const auto msr_bitmap = ExAllocatePoolWithTag(NonPagedPoolNx, PAGE_SIZE,
kHyperPlatformCommonPoolTag);
if (!msr_bitmap) {
ExFreePoolWithTag(shared_data, kHyperPlatformCommonPoolTag);
return nullptr;
}
RtlZeroMemory(msr_bitmap, PAGE_SIZE);
shared_data->msr_bitmap = msr_bitmap;
// Checks MSRs causing #GP and should not cause VM-exit from 0 to 0xfff.
bool unsafe_msr_map[0x1000] = {};
for (auto msr = 0ul; msr < RTL_NUMBER_OF(unsafe_msr_map); ++msr) {
__try {
UtilReadMsr(static_cast<Msr>(msr));
} __except (EXCEPTION_EXECUTE_HANDLER) {
unsafe_msr_map[msr] = true;
}
}
// Activate VM-exit for RDMSR against all MSRs
const auto bitmap_read_low = reinterpret_cast<UCHAR *>(msr_bitmap);
const auto bitmap_read_high = bitmap_read_low + 1024;
RtlFillMemory(bitmap_read_low, 1024, 0xff); // read 0 - 1fff
RtlFillMemory(bitmap_read_high, 1024, 0xff); // read c0000000 - c0001fff
// But ignore IA32_MPERF (000000e7) and IA32_APERF (000000e8)
RTL_BITMAP bitmap_read_low_header = {};
RtlInitializeBitMap(&bitmap_read_low_header,
reinterpret_cast<PULONG>(bitmap_read_low), 1024 * 8);
RtlClearBits(&bitmap_read_low_header, 0xe7, 2);
// Also ignore the unsage MSRs
for (auto msr = 0ul; msr < RTL_NUMBER_OF(unsafe_msr_map); ++msr) {
const auto ignore = unsafe_msr_map[msr];
if (ignore) {
RtlClearBits(&bitmap_read_low_header, msr, 1);
}
}
// But ignore IA32_GS_BASE (c0000101) and IA32_KERNEL_GS_BASE (c0000102)
RTL_BITMAP bitmap_read_high_header = {};
RtlInitializeBitMap(&bitmap_read_high_header,
reinterpret_cast<PULONG>(bitmap_read_high), 1024 * 8);
RtlClearBits(&bitmap_read_high_header, 0x101, 2);
return shared_data;
}
// Build MSR bitmap
_Use_decl_annotations_ static void *VmpBuildMsrBitmap() {
PAGED_CODE();
const auto msr_bitmap = ExAllocatePoolWithTag(NonPagedPool, PAGE_SIZE,
kHyperPlatformCommonPoolTag);
if (!msr_bitmap) {
return nullptr;
}
RtlZeroMemory(msr_bitmap, PAGE_SIZE);
// Activate VM-exit for RDMSR against all MSRs
const auto bitmap_read_low = reinterpret_cast<UCHAR *>(msr_bitmap);
const auto bitmap_read_high = bitmap_read_low + 1024;
RtlFillMemory(bitmap_read_low, 1024, 0xff); // read 0 - 1fff
RtlFillMemory(bitmap_read_high, 1024, 0xff); // read c0000000 - c0001fff
// Ignore IA32_MPERF (000000e7) and IA32_APERF (000000e8)
RTL_BITMAP bitmap_read_low_header = {};
RtlInitializeBitMap(&bitmap_read_low_header,
reinterpret_cast<PULONG>(bitmap_read_low), 1024 * 8);
RtlClearBits(&bitmap_read_low_header, 0xe7, 2);
// Checks MSRs that cause #GP from 0 to 0xfff, and ignore all of them
for (auto msr = 0ul; msr < 0x1000; ++msr) {
__try {
UtilReadMsr(static_cast<Msr>(msr));
} __except (EXCEPTION_EXECUTE_HANDLER) {
RtlClearBits(&bitmap_read_low_header, msr, 1);
}
}
// Ignore IA32_GS_BASE (c0000101) and IA32_KERNEL_GS_BASE (c0000102)
RTL_BITMAP bitmap_read_high_header = {};
RtlInitializeBitMap(&bitmap_read_high_header,
reinterpret_cast<PULONG>(bitmap_read_high),
1024 * CHAR_BIT);
RtlClearBits(&bitmap_read_high_header, 0x101, 2);
return msr_bitmap;
}
// 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) {
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.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.acknowledge_interrupt_on_exit = true;
vm_exitctl_requested.fields.host_address_space_size = IsX64();
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_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.enable_rdtscp = true; // required for Win10
vm_procctl2_requested.fields.descriptor_table_exiting = true;
// required for Win10
vm_procctl2_requested.fields.enable_xsaves_xstors = true;
VmxSecondaryProcessorBasedControls vm_procctl2 = {VmpAdjustControlValue(
Msr::kIa32VmxProcBasedCtls2, vm_procctl2_requested.all)};
// 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 = {};
Cr4 cr4_mask = {};
// 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;
}
const auto exception_bitmap =
// 1 << InterruptionVector::kBreakpointException |
// 1 << InterruptionVector::kGeneralProtectionException |
// 1 << InterruptionVector::kPageFaultException |
0;
// clang-format off
/* 16-Bit Control Field */
/* 16-Bit Guest-State Fields */
auto error = VmxStatus::kOk;
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, 0);
error |= UtilVmWrite64(VmcsField::kIoBitmapB, 0);
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::kPageFaultErrorCodeMask, 0);
error |= UtilVmWrite(VmcsField::kPageFaultErrorCodeMatch, 0);
error |= UtilVmWrite(VmcsField::kCr3TargetCount, 0);
error |= UtilVmWrite(VmcsField::kVmExitControls, vm_exitctl.all);
error |= UtilVmWrite(VmcsField::kVmExitMsrStoreCount, 0);
error |= UtilVmWrite(VmcsField::kVmExitMsrLoadCount, 0);
error |= UtilVmWrite(VmcsField::kVmEntryControls, vm_entryctl.all);
error |= UtilVmWrite(VmcsField::kVmEntryMsrLoadCount, 0);
error |= UtilVmWrite(VmcsField::kVmEntryIntrInfoField, 0);
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::kGuestInterruptibilityInfo, 0);
error |= UtilVmWrite(VmcsField::kGuestActivityState, 0);
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, __readcr0());
error |= UtilVmWrite(VmcsField::kCr4ReadShadow, __readcr4());
/* 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;
}
