---
title: Virtual Machine Control Structure (VMCS) Field IDs
framework: Hypervisor
role: collectionGroup
role_heading: API Collection
path: hypervisor/virtual-machine-control-structure-vmcs-field-ids
---

# Virtual Machine Control Structure (VMCS) Field IDs

Fields you can read or change using the Hypervisor framework’s read and write functions.

## Overview

Overview You can examine the state of, or control the operation of the framework and indivudal guests through various fields in the Virtual Machine Control Structure. The VMCS fields listed below describe which fields are read-only or read-write using the Hypervisor framework’s read and write functions. Readable and Writable VMCS Guest Fields These are fields, states, flags, and registers in hypervisor guests that you can read from or write to. In some instances there are limitations on what you can read or write, such as specific regsters or bit positions as indicated for each field. RIP, RSP, RFLAGS CR3, CR4, DR7 PDTR — {0, 1, 2, 3} CR3-Target — {0, 1, 2, 3} IA32_SYSENTER_CS IA32_SYSENTER_ESP IA32_SYSENTER_EIP IA32_EFER Interruptibility State Pending Debug Exceptions Selector — {ES, CS, SS, DS, FS, GS, LDTR, TR} Base — {ES, CS, SS, DS, FS, GS, LDTR, TR, GDTR, ITDR} Limit — {ES, CS, SS, DS, FS, GS, LDTR, TR, GDTR, ITDR} Access Rights — {ES, CS, SS, FS, GS, LDTR, TR}. Readable and Writable VMCS Control Fields These control fields that you can both read and write. Exception Bitmap Framework Hypervisor Page-Fault Error-Code Mask VM-Entry Interruption-Information Field VM-Entry Exception Error Code VM-Entry Instruction Length TPR Threshold PLE Gap PLE Window CR0 Guest/Host Mask CR4 Guest/Host Mask CR0 Read Shadow CR4 Read Shadow Readable and Conditionally Writable VMCS Guest Fields These guest fields describe the guest’s control registers and activity state. Updating these field requires the conditions listed for each field: CR0 — CR0.CD and CR0.NW are unset Activity State — The current state must be either ACTIVE or HLT Readable and Conditionally Writable VMCS Control Fields These fields describe VM execution controls, and access to the framework’s guest/host mask. Reading or updating these field requires the conditions listed for each field: Pin-Based VM-Execution Controls — hv_vmx_read_capability(_:_:) must be true Primary Processor-Based VM-Execution Controls — hv_vmx_read_capability(_:_:) must be true Secondary Processor-Based VM-Execution Controls — hv_vmx_read_capability(_:_:) must be true VM Entry Controls — hv_vmx_read_capability(_:_:) must be true CR0 Guest/Host Mask — CR0.CD and CR0.NW are set Read-Only VMCS Control Fields These read-only fields provide information about time-stamp counter offsets and programmable interrupt controllers addresses: TCS Offset APIC-Access Address Read-Only VMCS Data Fields These read-only fields describe error and exit information, interrupt descriptor tables, or guest address information: VM-Instruction Error Exit Reason VM-Exit Interruption Information VM-Exit Interruption Error Code IDT-Vectoring Information Field IDT-Vectoring Error Code VM-Exit Instruction Length VM-Exit Instruction Information Guest-Physical Address Exit Qualification Guest-Linear Address

## Topics

### Enumerations

- [VM Creation Options](hypervisor/1447306-vm-creation-options.md)
- [VM Capabilities](hypervisor/3181560-vm-capabilities.md)
- [hv_cache_type_t](hypervisor/hv_cache_type_t.md)
- [hv_boot_state](hypervisor/hv_boot_state.md)
- [hv_apic_ctrl_t](hypervisor/hv_apic_ctrl_t.md)
- [hv_apic_intr_trigger_t](hypervisor/hv_apic_intr_trigger_t.md)
- [hv_apic_lvt_flavor_t](hypervisor/hv_apic_lvt_flavor_t.md)
- [hv_gic_distributor_reg_t](hypervisor/hv_gic_distributor_reg_t.md)
- [hv_gic_icc_reg_t](hypervisor/hv_gic_icc_reg_t.md)
- [hv_gic_ich_reg_t](hypervisor/hv_gic_ich_reg_t.md)
- [hv_gic_icv_reg_t](hypervisor/hv_gic_icv_reg_t.md)
- [hv_gic_intid_t](hypervisor/hv_gic_intid_t.md)
- [hv_gic_msi_reg_t](hypervisor/hv_gic_msi_reg_t.md)
- [hv_gic_redistributor_reg_t](hypervisor/hv_gic_redistributor_reg_t.md)
- [hv_sme_p_reg_t](hypervisor/hv_sme_p_reg_t.md)
- [hv_sme_z_reg_t](hypervisor/hv_sme_z_reg_t.md)
- [hv_vm_exitinfo_t](hypervisor/hv_vm_exitinfo_t.md)

## See Also

### Field management

- [hv_vmx_vcpu_read_vmcs(_:_:_:)](hypervisor/hv_vmx_vcpu_read_vmcs(_:_:_:).md)
- [hv_vmx_vcpu_write_vmcs(_:_:_:)](hypervisor/hv_vmx_vcpu_write_vmcs(_:_:_:).md)
- [hv_vmx_vcpu_get_cap_write_vmcs(_:_:_:_:)](hypervisor/hv_vmx_vcpu_get_cap_write_vmcs(_:_:_:_:).md)
- [hv_vmx_vcpu_set_apic_address(_:_:)](hypervisor/hv_vmx_vcpu_set_apic_address(_:_:).md)
- [Virtual Machine control structure (VMCS) Field IDs](hypervisor/1469436-virtual_machine_control_structur-enum.md)