    /******************************************************************************
     * xen-x86_32.h
     *
     * Guest OS interface to x86 32-bit Xen.
     *
     * Permission is hereby granted, free of charge, to any person obtaining a copy
     * of this software and associated documentation files (the "Software"), to
     * deal in the Software without restriction, including without limitation the
     * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
     * sell copies of the Software, and to permit persons to whom the Software is
     * furnished to do so, subject to the following conditions:
     *
     * The above copyright notice and this permission notice shall be included in
     * all copies or substantial portions of the Software.
     *
     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
     * DEALINGS IN THE SOFTWARE.
     *
     * Copyright (c) 2004-2007, K A Fraser
     */

    #ifndef __XEN_PUBLIC_ARCH_X86_XEN_X86_32_H__
    #define __XEN_PUBLIC_ARCH_X86_XEN_X86_32_H__

    /*
     * Hypercall interface:
     *  Input:  %ebx, %ecx, %edx, %esi, %edi, %ebp (arguments 1-6)
     *  Output: %eax
     * Access is via hypercall page (set up by guest loader or via a Xen MSR):
     *  call hypercall_page + hypercall-number * 32
     * Clobbered: Argument registers (e.g., 2-arg hypercall clobbers %ebx,%ecx)
     */

    /*
     * These flat segments are in the Xen-private section of every GDT. Since these
     * are also present in the initial GDT, many OSes will be able to avoid
     * installing their own GDT.
     */
    #define FLAT_RING1_CS 0xe019    /* GDT index 259 */
    #define FLAT_RING1_DS 0xe021    /* GDT index 260 */
    #define FLAT_RING1_SS 0xe021    /* GDT index 260 */
    #define FLAT_RING3_CS 0xe02b    /* GDT index 261 */
    #define FLAT_RING3_DS 0xe033    /* GDT index 262 */
    #define FLAT_RING3_SS 0xe033    /* GDT index 262 */

    #define FLAT_KERNEL_CS FLAT_RING1_CS
    #define FLAT_KERNEL_DS FLAT_RING1_DS
    #define FLAT_KERNEL_SS FLAT_RING1_SS
    #define FLAT_USER_CS    FLAT_RING3_CS
    #define FLAT_USER_DS    FLAT_RING3_DS
    #define FLAT_USER_SS    FLAT_RING3_SS

    #define __HYPERVISOR_VIRT_START_PAE    0xF5800000
    #define __MACH2PHYS_VIRT_START_PAE     0xF5800000
    #define __MACH2PHYS_VIRT_END_PAE       0xF6800000
    #define HYPERVISOR_VIRT_START_PAE      xen_mk_ulong(__HYPERVISOR_VIRT_START_PAE)
    #define MACH2PHYS_VIRT_START_PAE       xen_mk_ulong(__MACH2PHYS_VIRT_START_PAE)
    #define MACH2PHYS_VIRT_END_PAE         xen_mk_ulong(__MACH2PHYS_VIRT_END_PAE)

    /* Non-PAE bounds are obsolete. */
    #define __HYPERVISOR_VIRT_START_NONPAE 0xFC000000
    #define __MACH2PHYS_VIRT_START_NONPAE  0xFC000000
    #define __MACH2PHYS_VIRT_END_NONPAE    0xFC400000
    #define HYPERVISOR_VIRT_START_NONPAE   \
        xen_mk_ulong(__HYPERVISOR_VIRT_START_NONPAE)
    #define MACH2PHYS_VIRT_START_NONPAE    \
        xen_mk_ulong(__MACH2PHYS_VIRT_START_NONPAE)
    #define MACH2PHYS_VIRT_END_NONPAE      \
        xen_mk_ulong(__MACH2PHYS_VIRT_END_NONPAE)

    #define __HYPERVISOR_VIRT_START __HYPERVISOR_VIRT_START_PAE
    #define __MACH2PHYS_VIRT_START  __MACH2PHYS_VIRT_START_PAE
    #define __MACH2PHYS_VIRT_END    __MACH2PHYS_VIRT_END_PAE

    #ifndef HYPERVISOR_VIRT_START
    #define HYPERVISOR_VIRT_START xen_mk_ulong(__HYPERVISOR_VIRT_START)
    #endif

    #define MACH2PHYS_VIRT_START  xen_mk_ulong(__MACH2PHYS_VIRT_START)
    #define MACH2PHYS_VIRT_END    xen_mk_ulong(__MACH2PHYS_VIRT_END)
    #define MACH2PHYS_NR_ENTRIES  ((MACH2PHYS_VIRT_END-MACH2PHYS_VIRT_START)>>2)
    #ifndef machine_to_phys_mapping
    #define machine_to_phys_mapping ((unsigned long *)MACH2PHYS_VIRT_START)
    #endif

    /* 32-/64-bit invariability for control interfaces (domctl/sysctl). */
    #if defined(__XEN__) || defined(__XEN_TOOLS__)
    #undef ___DEFINE_XEN_GUEST_HANDLE
    #define ___DEFINE_XEN_GUEST_HANDLE(name, type)                  \
        typedef struct { type *p; }                                 \
            __guest_handle_ ## name;                                \
        typedef struct { union { type *p; uint64_aligned_t q; }; }  \
            __guest_handle_64_ ## name
    #undef set_xen_guest_handle_raw
    #define set_xen_guest_handle_raw(hnd, val)                  \
        do { if ( sizeof(hnd) == 8 ) *(uint64_t *)&(hnd) = 0;   \
             (hnd).p = val;                                     \
        } while ( 0 )
    #define  int64_aligned_t  int64_t __attribute__((aligned(8)))
    #define uint64_aligned_t uint64_t __attribute__((aligned(8)))
    #define __XEN_GUEST_HANDLE_64(name) __guest_handle_64_ ## name
    #define XEN_GUEST_HANDLE_64(name) __XEN_GUEST_HANDLE_64(name)
    #endif

    #ifndef __ASSEMBLY__

    #if defined(XEN_GENERATING_COMPAT_HEADERS)
    /* nothing */
    #elif defined(__XEN__) || defined(__XEN_TOOLS__)
    /* Anonymous unions include all permissible names (e.g., al/ah/ax/eax). */
    #define __DECL_REG_LO8(which) union { \
        uint32_t e ## which ## x; \
        uint16_t which ## x; \
        struct { \
            uint8_t which ## l; \
            uint8_t which ## h; \
        }; \
    }
    #define __DECL_REG_LO16(name) union { \
        uint32_t e ## name, _e ## name; \
        uint16_t name; \
    }
    #else
    /* Other sources must always use the proper 32-bit name (e.g., eax). */
    #define __DECL_REG_LO8(which) uint32_t e ## which ## x
    #define __DECL_REG_LO16(name) uint32_t e ## name
    #endif

    struct cpu_user_regs {
        __DECL_REG_LO8(b);
        __DECL_REG_LO8(c);
        __DECL_REG_LO8(d);
        __DECL_REG_LO16(si);
        __DECL_REG_LO16(di);
        __DECL_REG_LO16(bp);
        __DECL_REG_LO8(a);
        uint16_t error_code;    /* private */
        uint16_t entry_vector;  /* private */
        __DECL_REG_LO16(ip);
        uint16_t cs;
        uint8_t  saved_upcall_mask;
        uint8_t  _pad0;
        __DECL_REG_LO16(flags); /* eflags.IF == !saved_upcall_mask */
        __DECL_REG_LO16(sp);
        uint16_t ss, _pad1;
        uint16_t es, _pad2;
        uint16_t ds, _pad3;
        uint16_t fs, _pad4;
        uint16_t gs, _pad5;
    };
    typedef struct cpu_user_regs cpu_user_regs_t;
    DEFINE_XEN_GUEST_HANDLE(cpu_user_regs_t);

    #undef __DECL_REG_LO8
    #undef __DECL_REG_LO16

    /*
     * Page-directory addresses above 4GB do not fit into architectural %cr3.
     * When accessing %cr3, or equivalent field in vcpu_guest_context, guests
     * must use the following accessor macros to pack/unpack valid MFNs.
     */
    #define xen_pfn_to_cr3(pfn) (((unsigned)(pfn) << 12) | ((unsigned)(pfn) >> 20))
    #define xen_cr3_to_pfn(cr3) (((unsigned)(cr3) >> 12) | ((unsigned)(cr3) << 20))

    struct arch_vcpu_info {
        unsigned long cr2;
        unsigned long pad[5]; /* sizeof(vcpu_info_t) == 64 */
    };
    typedef struct arch_vcpu_info arch_vcpu_info_t;

    struct xen_callback {
        unsigned long cs;
        unsigned long eip;
    };
    typedef struct xen_callback xen_callback_t;

    #endif /* !__ASSEMBLY__ */

    #endif /* __XEN_PUBLIC_ARCH_X86_XEN_X86_32_H__ */

    /*
     * Local variables:
     * mode: C
     * c-file-style: "BSD"
     * c-basic-offset: 4
     * tab-width: 4
     * indent-tabs-mode: nil
     * End:
     */