xref: /OK3568_Linux_fs/kernel/include/uapi/linux/um_timetravel.h (revision 4882a59341e53eb6f0b4789bf948001014eff981) 
1*4882a593Smuzhiyun /*
2*4882a593Smuzhiyun  * Permission to use, copy, modify, and/or distribute this software for any
3*4882a593Smuzhiyun  * purpose with or without fee is hereby granted, provided that the above
4*4882a593Smuzhiyun  * copyright notice and this permission notice appear in all copies.
5*4882a593Smuzhiyun  *
6*4882a593Smuzhiyun  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
7*4882a593Smuzhiyun  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
8*4882a593Smuzhiyun  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
9*4882a593Smuzhiyun  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
10*4882a593Smuzhiyun  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
11*4882a593Smuzhiyun  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
12*4882a593Smuzhiyun  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
13*4882a593Smuzhiyun  *
14*4882a593Smuzhiyun  * Copyright (C) 2019 Intel Corporation
15*4882a593Smuzhiyun  */
16*4882a593Smuzhiyun #ifndef _UAPI_LINUX_UM_TIMETRAVEL_H
17*4882a593Smuzhiyun #define _UAPI_LINUX_UM_TIMETRAVEL_H
18*4882a593Smuzhiyun #include <linux/types.h>
19*4882a593Smuzhiyun 
20*4882a593Smuzhiyun /**
21*4882a593Smuzhiyun  * struct um_timetravel_msg - UM time travel message
22*4882a593Smuzhiyun  *
23*4882a593Smuzhiyun  * This is the basic message type, going in both directions.
24*4882a593Smuzhiyun  *
25*4882a593Smuzhiyun  * This is the message passed between the host (user-mode Linux instance)
26*4882a593Smuzhiyun  * and the calendar (the application on the other side of the socket) in
27*4882a593Smuzhiyun  * order to implement common scheduling.
28*4882a593Smuzhiyun  *
29*4882a593Smuzhiyun  * Whenever UML has an event it will request runtime for it from the
30*4882a593Smuzhiyun  * calendar, and then wait for its turn until it can run, etc. Note
31*4882a593Smuzhiyun  * that it will only ever request the single next runtime, i.e. multiple
32*4882a593Smuzhiyun  * REQUEST messages override each other.
33*4882a593Smuzhiyun  */
34*4882a593Smuzhiyun struct um_timetravel_msg {
35*4882a593Smuzhiyun 	/**
36*4882a593Smuzhiyun 	 * @op: operation value from &enum um_timetravel_ops
37*4882a593Smuzhiyun 	 */
38*4882a593Smuzhiyun 	__u32 op;
39*4882a593Smuzhiyun 
40*4882a593Smuzhiyun 	/**
41*4882a593Smuzhiyun 	 * @seq: sequence number for the message - shall be reflected in
42*4882a593Smuzhiyun 	 *	the ACK response, and should be checked while processing
43*4882a593Smuzhiyun 	 *	the response to see if it matches
44*4882a593Smuzhiyun 	 */
45*4882a593Smuzhiyun 	__u32 seq;
46*4882a593Smuzhiyun 
47*4882a593Smuzhiyun 	/**
48*4882a593Smuzhiyun 	 * @time: time in nanoseconds
49*4882a593Smuzhiyun 	 */
50*4882a593Smuzhiyun 	__u64 time;
51*4882a593Smuzhiyun };
52*4882a593Smuzhiyun 
53*4882a593Smuzhiyun /**
54*4882a593Smuzhiyun  * enum um_timetravel_ops - Operation codes
55*4882a593Smuzhiyun  */
56*4882a593Smuzhiyun enum um_timetravel_ops {
57*4882a593Smuzhiyun 	/**
58*4882a593Smuzhiyun 	 * @UM_TIMETRAVEL_ACK: response (ACK) to any previous message,
59*4882a593Smuzhiyun 	 *	this usually doesn't carry any data in the 'time' field
60*4882a593Smuzhiyun 	 *	unless otherwise specified below
61*4882a593Smuzhiyun 	 */
62*4882a593Smuzhiyun 	UM_TIMETRAVEL_ACK		= 0,
63*4882a593Smuzhiyun 
64*4882a593Smuzhiyun 	/**
65*4882a593Smuzhiyun 	 * @UM_TIMETRAVEL_START: initialize the connection, the time
66*4882a593Smuzhiyun 	 *	field contains an (arbitrary) ID to possibly be able
67*4882a593Smuzhiyun 	 *	to distinguish the connections.
68*4882a593Smuzhiyun 	 */
69*4882a593Smuzhiyun 	UM_TIMETRAVEL_START		= 1,
70*4882a593Smuzhiyun 
71*4882a593Smuzhiyun 	/**
72*4882a593Smuzhiyun 	 * @UM_TIMETRAVEL_REQUEST: request to run at the given time
73*4882a593Smuzhiyun 	 *	(host -> calendar)
74*4882a593Smuzhiyun 	 */
75*4882a593Smuzhiyun 	UM_TIMETRAVEL_REQUEST		= 2,
76*4882a593Smuzhiyun 
77*4882a593Smuzhiyun 	/**
78*4882a593Smuzhiyun 	 * @UM_TIMETRAVEL_WAIT: Indicate waiting for the previously requested
79*4882a593Smuzhiyun 	 *	runtime, new requests may be made while waiting (e.g. due to
80*4882a593Smuzhiyun 	 *	interrupts); the time field is ignored. The calendar must process
81*4882a593Smuzhiyun 	 *	this message and later	send a %UM_TIMETRAVEL_RUN message when
82*4882a593Smuzhiyun 	 *	the host can run again.
83*4882a593Smuzhiyun 	 *	(host -> calendar)
84*4882a593Smuzhiyun 	 */
85*4882a593Smuzhiyun 	UM_TIMETRAVEL_WAIT		= 3,
86*4882a593Smuzhiyun 
87*4882a593Smuzhiyun 	/**
88*4882a593Smuzhiyun 	 * @UM_TIMETRAVEL_GET: return the current time from the calendar in the
89*4882a593Smuzhiyun 	 *	ACK message, the time in the request message is ignored
90*4882a593Smuzhiyun 	 *	(host -> calendar)
91*4882a593Smuzhiyun 	 */
92*4882a593Smuzhiyun 	UM_TIMETRAVEL_GET		= 4,
93*4882a593Smuzhiyun 
94*4882a593Smuzhiyun 	/**
95*4882a593Smuzhiyun 	 * @UM_TIMETRAVEL_UPDATE: time update to the calendar, must be sent e.g.
96*4882a593Smuzhiyun 	 *	before kicking an interrupt to another calendar
97*4882a593Smuzhiyun 	 *	(host -> calendar)
98*4882a593Smuzhiyun 	 */
99*4882a593Smuzhiyun 	UM_TIMETRAVEL_UPDATE		= 5,
100*4882a593Smuzhiyun 
101*4882a593Smuzhiyun 	/**
102*4882a593Smuzhiyun 	 * @UM_TIMETRAVEL_RUN: run time request granted, current time is in
103*4882a593Smuzhiyun 	 *	the time field
104*4882a593Smuzhiyun 	 *	(calendar -> host)
105*4882a593Smuzhiyun 	 */
106*4882a593Smuzhiyun 	UM_TIMETRAVEL_RUN		= 6,
107*4882a593Smuzhiyun 
108*4882a593Smuzhiyun 	/**
109*4882a593Smuzhiyun 	 * @UM_TIMETRAVEL_FREE_UNTIL: Enable free-running until the given time,
110*4882a593Smuzhiyun 	 *	this is a message from the calendar telling the host that it can
111*4882a593Smuzhiyun 	 *	freely do its own scheduling for anything before the indicated
112*4882a593Smuzhiyun 	 *	time.
113*4882a593Smuzhiyun 	 *	Note that if a calendar sends this message once, the host may
114*4882a593Smuzhiyun 	 *	assume that it will also do so in the future, if it implements
115*4882a593Smuzhiyun 	 *	wraparound semantics for the time field.
116*4882a593Smuzhiyun 	 *	(calendar -> host)
117*4882a593Smuzhiyun 	 */
118*4882a593Smuzhiyun 	UM_TIMETRAVEL_FREE_UNTIL	= 7,
119*4882a593Smuzhiyun 
120*4882a593Smuzhiyun 	/**
121*4882a593Smuzhiyun 	 * @UM_TIMETRAVEL_GET_TOD: Return time of day, typically used once at
122*4882a593Smuzhiyun 	 *	boot by the virtual machines to get a synchronized time from
123*4882a593Smuzhiyun 	 *	the simulation.
124*4882a593Smuzhiyun 	 */
125*4882a593Smuzhiyun 	UM_TIMETRAVEL_GET_TOD		= 8,
126*4882a593Smuzhiyun };
127*4882a593Smuzhiyun 
128*4882a593Smuzhiyun #endif /* _UAPI_LINUX_UM_TIMETRAVEL_H */
129