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 
116 struct sched_shutdown {
117 	unsigned int reason; /* SHUTDOWN_* => shutdown reason */
118 };
119 
120 DEFINE_GUEST_HANDLE_STRUCT(sched_shutdown);
121 
122 struct sched_poll {
123 	GUEST_HANDLE(evtchn_port_t)ports;
124 	unsigned int nr_ports;
125 	u64 timeout;
126 };
127 
128 DEFINE_GUEST_HANDLE_STRUCT(sched_poll);
129 
130 struct sched_remote_shutdown {
131 	domid_t domain_id;         /* Remote domain ID */
132 	unsigned int reason;       /* SHUTDOWN_* => shutdown reason */
133 };
134 
135 DEFINE_GUEST_HANDLE_STRUCT(sched_remote_shutdown);
136 
137 struct sched_watchdog {
138 	u32 id;                /* watchdog ID */
139 	u32 timeout;           /* timeout */
140 };
141 
142 DEFINE_GUEST_HANDLE_STRUCT(sched_watchdog);
143 
144 struct sched_pin_override {
145 	s32 pcpu;
146 };
147 
148 DEFINE_GUEST_HANDLE_STRUCT(sched_pin_override);
149 
150 /*
151  * Reason codes for SCHEDOP_shutdown. These may be interpreted by control
152  * software to determine the appropriate action. For the most part, Xen does
153  * not care about the shutdown code.
154  */
155 #define SHUTDOWN_poweroff   0  /* Domain exited normally. Clean up and kill. */
156 #define SHUTDOWN_reboot     1  /* Clean up, kill, and then restart.          */
157 #define SHUTDOWN_suspend    2  /* Clean up, save suspend info, kill.         */
158 #define SHUTDOWN_crash      3  /* Tell controller we've crashed.             */
159 #define SHUTDOWN_watchdog   4  /* Restart because watchdog time expired.     */
160 
161 /*
162  * Domain asked to perform 'soft reset' for it. The expected behavior is to
163  * reset internal Xen state for the domain returning it to the point where it
164  * was created but leaving the domain's memory contents and vCPU contexts
165  * intact. This will allow the domain to start over and set up all Xen specific
166  * interfaces again.
167  */
168 #define SHUTDOWN_soft_reset 5
169 #define SHUTDOWN_MAX        5  /* Maximum valid shutdown reason.             */
170 
171 #endif /* __XEN_PUBLIC_SCHED_H__ */
172