    /* SPDX-License-Identifier: MIT */
    /******************************************************************************
     * arch-x86/cpuid.h
     *
     * CPUID interface to Xen.
     *
     * Copyright (c) 2007 Citrix Systems, Inc.
     *
     * Authors:
     *    Keir Fraser <keir@xen.org>
     */

    #ifndef __XEN_PUBLIC_ARCH_X86_CPUID_H__
    #define __XEN_PUBLIC_ARCH_X86_CPUID_H__

    /*
     * For compatibility with other hypervisor interfaces, the Xen cpuid leaves
     * can be found at the first otherwise unused 0x100 aligned boundary starting
     * from 0x40000000.
     *
     * e.g If viridian extensions are enabled for an HVM domain, the Xen cpuid
     * leaves will start at 0x40000100
     */

    #define XEN_CPUID_FIRST_LEAF 0x40000000
    #define XEN_CPUID_LEAF(i)    (XEN_CPUID_FIRST_LEAF + (i))

    /*
     * Leaf 1 (0x40000x00)
     * EAX: Largest Xen-information leaf. All leaves up to an including @EAX
     *      are supported by the Xen host.
     * EBX-EDX: "XenVMMXenVMM" signature, allowing positive identification
     *      of a Xen host.
     */
    #define XEN_CPUID_SIGNATURE_EBX 0x566e6558 /* "XenV" */
    #define XEN_CPUID_SIGNATURE_ECX 0x65584d4d /* "MMXe" */
    #define XEN_CPUID_SIGNATURE_EDX 0x4d4d566e /* "nVMM" */

    /*
     * Leaf 2 (0x40000x01)
     * EAX[31:16]: Xen major version.
     * EAX[15: 0]: Xen minor version.
     * EBX-EDX: Reserved (currently all zeroes).
     */

    /*
     * Leaf 3 (0x40000x02)
     * EAX: Number of hypercall transfer pages. This register is always guaranteed
     *      to specify one hypercall page.
     * EBX: Base address of Xen-specific MSRs.
     * ECX: Features 1. Unused bits are set to zero.
     * EDX: Features 2. Unused bits are set to zero.
     */

    /* Does the host support MMU_PT_UPDATE_PRESERVE_AD for this guest? */
    #define _XEN_CPUID_FEAT1_MMU_PT_UPDATE_PRESERVE_AD 0
    #define XEN_CPUID_FEAT1_MMU_PT_UPDATE_PRESERVE_AD  (1u<<0)

    /*
     * Leaf 4 (0x40000x03)
     * Sub-leaf 0: EAX: bit 0: emulated tsc
     *                  bit 1: host tsc is known to be reliable
     *                  bit 2: RDTSCP instruction available
     *             EBX: tsc_mode: 0=default (emulate if necessary), 1=emulate,
     *                            2=no emulation, 3=no emulation + TSC_AUX support
     *             ECX: guest tsc frequency in kHz
     *             EDX: guest tsc incarnation (migration count)
     * Sub-leaf 1: EAX: tsc offset low part
     *             EBX: tsc offset high part
     *             ECX: multiplicator for tsc->ns conversion
     *             EDX: shift amount for tsc->ns conversion
     * Sub-leaf 2: EAX: host tsc frequency in kHz
     */

    #define XEN_CPUID_TSC_EMULATED               (1u << 0)
    #define XEN_CPUID_HOST_TSC_RELIABLE          (1u << 1)
    #define XEN_CPUID_RDTSCP_INSTR_AVAIL         (1u << 2)

    #define XEN_CPUID_TSC_MODE_DEFAULT           (0)
    #define XEN_CPUID_TSC_MODE_ALWAYS_EMULATE    (1u)
    #define XEN_CPUID_TSC_MODE_NEVER_EMULATE     (2u)
    #define XEN_CPUID_TSC_MODE_PVRDTSCP          (3u)

    /*
     * Leaf 5 (0x40000x04)
     * HVM-specific features
     * Sub-leaf 0: EAX: Features
     * Sub-leaf 0: EBX: vcpu id (iff EAX has XEN_HVM_CPUID_VCPU_ID_PRESENT flag)
     * Sub-leaf 0: ECX: domain id (iff EAX has XEN_HVM_CPUID_DOMID_PRESENT flag)
     */
    #define XEN_HVM_CPUID_APIC_ACCESS_VIRT (1u << 0) /* Virtualized APIC registers */
    #define XEN_HVM_CPUID_X2APIC_VIRT      (1u << 1) /* Virtualized x2APIC accesses */
    /* Memory mapped from other domains has valid IOMMU entries */
    #define XEN_HVM_CPUID_IOMMU_MAPPINGS   (1u << 2)
    #define XEN_HVM_CPUID_VCPU_ID_PRESENT  (1u << 3) /* vcpu id is present in EBX */
    #define XEN_HVM_CPUID_DOMID_PRESENT    (1u << 4) /* domid is present in ECX */
    /*
     * With interrupt format set to 0 (non-remappable) bits 55:49 from the
     * IO-APIC RTE and bits 11:5 from the MSI address can be used to store
     * high bits for the Destination ID. This expands the Destination ID
     * field from 8 to 15 bits, allowing to target APIC IDs up 32768.
     */
    #define XEN_HVM_CPUID_EXT_DEST_ID      (1u << 5)
    /*
     * Per-vCPU event channel upcalls work correctly with physical IRQs
     * bound to event channels.
     */
    #define XEN_HVM_CPUID_UPCALL_VECTOR    (1u << 6)

    /*
     * Leaf 6 (0x40000x05)
     * PV-specific parameters
     * Sub-leaf 0: EAX: max available sub-leaf
     * Sub-leaf 0: EBX: bits 0-7: max machine address width
     */

    /* Max. address width in bits taking memory hotplug into account. */
    #define XEN_CPUID_MACHINE_ADDRESS_WIDTH_MASK (0xffu << 0)

    #define XEN_CPUID_MAX_NUM_LEAVES 5

    #endif /* __XEN_PUBLIC_ARCH_X86_CPUID_H__ */