1/* SPDX-License-Identifier: MIT */
2/******************************************************************************
3 * callback.h
4 *
5 * Register guest OS callbacks with Xen.
6 *
7 * Copyright (c) 2006, Ian Campbell
8 */
9
10#ifndef __XEN_PUBLIC_CALLBACK_H__
11#define __XEN_PUBLIC_CALLBACK_H__
12
13#include <xen/interface/xen.h>
14
15/*
16 * Prototype for this hypercall is:
17 * long callback_op(int cmd, void *extra_args)
18 * @cmd == CALLBACKOP_??? (callback operation).
19 * @extra_args == Operation-specific extra arguments (NULL if none).
20 */
21
22/* x86: Callback for event delivery. */
23#define CALLBACKTYPE_event 0
24
25/* x86: Failsafe callback when guest state cannot be restored by Xen. */
26#define CALLBACKTYPE_failsafe 1
27
28/* x86/64 hypervisor: Syscall by 64-bit guest app ('64-on-64-on-64'). */
29#define CALLBACKTYPE_syscall 2
30
31/*
32 * x86/32 hypervisor: Only available on x86/32 when supervisor_mode_kernel
33 * feature is enabled. Do not use this callback type in new code.
34 */
35#define CALLBACKTYPE_sysenter_deprecated 3
36
37/* x86: Callback for NMI delivery. */
38#define CALLBACKTYPE_nmi 4
39
40/*
41 * x86: sysenter is only available as follows:
42 * - 32-bit hypervisor: with the supervisor_mode_kernel feature enabled
43 * - 64-bit hypervisor: 32-bit guest applications on Intel CPUs
44 * ('32-on-32-on-64', '32-on-64-on-64')
45 * [nb. also 64-bit guest applications on Intel CPUs
46 * ('64-on-64-on-64'), but syscall is preferred]
47 */
48#define CALLBACKTYPE_sysenter 5
49
50/*
51 * x86/64 hypervisor: Syscall by 32-bit guest app on AMD CPUs
52 * ('32-on-32-on-64', '32-on-64-on-64')
53 */
54#define CALLBACKTYPE_syscall32 7
55
56/*
57 * Disable event deliver during callback? This flag is ignored for event and
58 * NMI callbacks: event delivery is unconditionally disabled.
59 */
60#define _CALLBACKF_mask_events 0
61#define CALLBACKF_mask_events (1U << _CALLBACKF_mask_events)
62
63/*
64 * Register a callback.
65 */
66#define CALLBACKOP_register 0
67struct callback_register {
68 uint16_t type;
69 uint16_t flags;
70 xen_callback_t address;
71};
72
73/*
74 * Unregister a callback.
75 *
76 * Not all callbacks can be unregistered. -EINVAL will be returned if
77 * you attempt to unregister such a callback.
78 */
79#define CALLBACKOP_unregister 1
80struct callback_unregister {
81 uint16_t type;
82 uint16_t _unused;
83};
84
85#endif /* __XEN_PUBLIC_CALLBACK_H__ */
86

source code of linux/include/xen/interface/callback.h