/******************************************************************************
   * callback.h
   *
   * Register guest OS callbacks with 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) 2006, Ian Campbell
   */
  
  #ifndef __XEN_PUBLIC_CALLBACK_H__
  #define __XEN_PUBLIC_CALLBACK_H__
  
  #include <xen/interface/xen.h>
  
  /*
   * Prototype for this hypercall is:
   *   long callback_op(int cmd, void *extra_args)
   * @cmd        == CALLBACKOP_??? (callback operation).
   * @extra_args == Operation-specific extra arguments (NULL if none).
   */
  
  /* x86: Callback for event delivery. */
  #define CALLBACKTYPE_event                 0
  
  /* x86: Failsafe callback when guest state cannot be restored by Xen. */
  #define CALLBACKTYPE_failsafe              1
  
  /* x86/64 hypervisor: Syscall by 64-bit guest app ('64-on-64-on-64'). */
  #define CALLBACKTYPE_syscall               2
  
  /*
   * x86/32 hypervisor: Only available on x86/32 when supervisor_mode_kernel
   *     feature is enabled. Do not use this callback type in new code.
   */
  #define CALLBACKTYPE_sysenter_deprecated   3
  
  /* x86: Callback for NMI delivery. */
  #define CALLBACKTYPE_nmi                   4
  
  /*
   * x86: sysenter is only available as follows:
   * - 32-bit hypervisor: with the supervisor_mode_kernel feature enabled
   * - 64-bit hypervisor: 32-bit guest applications on Intel CPUs
   *                      ('32-on-32-on-64', '32-on-64-on-64')
   *                      [nb. also 64-bit guest applications on Intel CPUs
   *                           ('64-on-64-on-64'), but syscall is preferred]
   */
  #define CALLBACKTYPE_sysenter              5
  
  /*
   * x86/64 hypervisor: Syscall by 32-bit guest app on AMD CPUs
   *                    ('32-on-32-on-64', '32-on-64-on-64')
   */
  #define CALLBACKTYPE_syscall32             7
  
  /*
   * Disable event deliver during callback? This flag is ignored for event and
   * NMI callbacks: event delivery is unconditionally disabled.
   */
  #define _CALLBACKF_mask_events             0
  #define CALLBACKF_mask_events              (1U << _CALLBACKF_mask_events)
  
  /*
   * Register a callback.
   */
  #define CALLBACKOP_register                0
  struct callback_register {
  	uint16_t type;
  	uint16_t flags;
  	xen_callback_t address;
  };
  
  /*
   * Unregister a callback.
   *
   * Not all callbacks can be unregistered. -EINVAL will be returned if
   * you attempt to unregister such a callback.
   */
  #define CALLBACKOP_unregister              1
  struct callback_unregister {
      uint16_t type;
      uint16_t _unused;
  };
  
  #endif /* __XEN_PUBLIC_CALLBACK_H__ */