1/* SPDX-License-Identifier: MIT */
2/******************************************************************************
3 * sched.h
4 *
5 * Scheduler state interactions
6 *
7 * Copyright (c) 2005, Keir Fraser <keir@xensource.com>
8 */
9
10#ifndef __XEN_PUBLIC_SCHED_H__
11#define __XEN_PUBLIC_SCHED_H__
12
13#include <xen/interface/event_channel.h>
14
15/*
16 * Guest Scheduler Operations
17 *
18 * The SCHEDOP interface provides mechanisms for a guest to interact
19 * with the scheduler, including yield, blocking and shutting itself
20 * down.
21 */
22
23/*
24 * The prototype for this hypercall is:
25 * long HYPERVISOR_sched_op(enum sched_op cmd, void *arg, ...)
26 *
27 * @cmd == SCHEDOP_??? (scheduler operation).
28 * @arg == Operation-specific extra argument(s), as described below.
29 * ... == Additional Operation-specific extra arguments, described below.
30 *
31 * Versions of Xen prior to 3.0.2 provided only the following legacy version
32 * of this hypercall, supporting only the commands yield, block and shutdown:
33 * long sched_op(int cmd, unsigned long arg)
34 * @cmd == SCHEDOP_??? (scheduler operation).
35 * @arg == 0 (SCHEDOP_yield and SCHEDOP_block)
36 * == SHUTDOWN_* code (SCHEDOP_shutdown)
37 *
38 * This legacy version is available to new guests as:
39 * long HYPERVISOR_sched_op_compat(enum sched_op cmd, unsigned long arg)
40 */
41
42/*
43 * Voluntarily yield the CPU.
44 * @arg == NULL.
45 */
46#define SCHEDOP_yield 0
47
48/*
49 * Block execution of this VCPU until an event is received for processing.
50 * If called with event upcalls masked, this operation will atomically
51 * reenable event delivery and check for pending events before blocking the
52 * VCPU. This avoids a "wakeup waiting" race.
53 * @arg == NULL.
54 */
55#define SCHEDOP_block 1
56
57/*
58 * Halt execution of this domain (all VCPUs) and notify the system controller.
59 * @arg == pointer to sched_shutdown structure.
60 *
61 * If the sched_shutdown_t reason is SHUTDOWN_suspend then
62 * x86 PV guests must also set RDX (EDX for 32-bit guests) to the MFN
63 * of the guest's start info page. RDX/EDX is the third hypercall
64 * argument.
65 *
66 * In addition, which reason is SHUTDOWN_suspend this hypercall
67 * returns 1 if suspend was cancelled or the domain was merely
68 * checkpointed, and 0 if it is resuming in a new domain.
69 */
70#define SCHEDOP_shutdown 2
71
72/*
73 * Poll a set of event-channel ports. Return when one or more are pending. An
74 * optional timeout may be specified.
75 * @arg == pointer to sched_poll structure.
76 */
77#define SCHEDOP_poll 3
78
79/*
80 * Declare a shutdown for another domain. The main use of this function is
81 * in interpreting shutdown requests and reasons for fully-virtualized
82 * domains. A para-virtualized domain may use SCHEDOP_shutdown directly.
83 * @arg == pointer to sched_remote_shutdown structure.
84 */
85#define SCHEDOP_remote_shutdown 4
86
87/*
88 * Latch a shutdown code, so that when the domain later shuts down it
89 * reports this code to the control tools.
90 * @arg == sched_shutdown, as for SCHEDOP_shutdown.
91 */
92#define SCHEDOP_shutdown_code 5
93
94/*
95 * Setup, poke and destroy a domain watchdog timer.
96 * @arg == pointer to sched_watchdog structure.
97 * With id == 0, setup a domain watchdog timer to cause domain shutdown
98 * after timeout, returns watchdog id.
99 * With id != 0 and timeout == 0, destroy domain watchdog timer.
100 * With id != 0 and timeout != 0, poke watchdog timer and set new timeout.
101 */
102#define SCHEDOP_watchdog 6
103
104/*
105 * Override the current vcpu affinity by pinning it to one physical cpu or
106 * undo this override restoring the previous affinity.
107 * @arg == pointer to sched_pin_override structure.
108 *
109 * A negative pcpu value will undo a previous pin override and restore the
110 * previous cpu affinity.
111 * This call is allowed for the hardware domain only and requires the cpu
112 * to be part of the domain's cpupool.
113 */
114#define SCHEDOP_pin_override 7
115
116struct sched_shutdown {
117 unsigned int reason; /* SHUTDOWN_* => shutdown reason */
118};
119DEFINE_GUEST_HANDLE_STRUCT(sched_shutdown);
120
121struct sched_poll {
122 GUEST_HANDLE(evtchn_port_t) ports;
123 unsigned int nr_ports;
124 uint64_t timeout;
125};
126DEFINE_GUEST_HANDLE_STRUCT(sched_poll);
127
128struct sched_remote_shutdown {
129 domid_t domain_id; /* Remote domain ID */
130 unsigned int reason; /* SHUTDOWN_* => shutdown reason */
131};
132DEFINE_GUEST_HANDLE_STRUCT(sched_remote_shutdown);
133
134struct sched_watchdog {
135 uint32_t id; /* watchdog ID */
136 uint32_t timeout; /* timeout */
137};
138DEFINE_GUEST_HANDLE_STRUCT(sched_watchdog);
139
140struct sched_pin_override {
141 int32_t pcpu;
142};
143DEFINE_GUEST_HANDLE_STRUCT(sched_pin_override);
144
145/*
146 * Reason codes for SCHEDOP_shutdown. These may be interpreted by control
147 * software to determine the appropriate action. For the most part, Xen does
148 * not care about the shutdown code.
149 */
150#define SHUTDOWN_poweroff 0 /* Domain exited normally. Clean up and kill. */
151#define SHUTDOWN_reboot 1 /* Clean up, kill, and then restart. */
152#define SHUTDOWN_suspend 2 /* Clean up, save suspend info, kill. */
153#define SHUTDOWN_crash 3 /* Tell controller we've crashed. */
154#define SHUTDOWN_watchdog 4 /* Restart because watchdog time expired. */
155
156/*
157 * Domain asked to perform 'soft reset' for it. The expected behavior is to
158 * reset internal Xen state for the domain returning it to the point where it
159 * was created but leaving the domain's memory contents and vCPU contexts
160 * intact. This will allow the domain to start over and set up all Xen specific
161 * interfaces again.
162 */
163#define SHUTDOWN_soft_reset 5
164#define SHUTDOWN_MAX 5 /* Maximum valid shutdown reason. */
165
166#endif /* __XEN_PUBLIC_SCHED_H__ */
167