129 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			129 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			C
		
	
	
	
/*
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 * Permission to use, copy, modify, and/or distribute this software for any
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 * purpose with or without fee is hereby granted, provided that the above
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 * copyright notice and this permission notice appear in all copies.
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 *
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 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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 *
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 * Copyright (C) 2019 Intel Corporation
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 */
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#ifndef _UAPI_LINUX_UM_TIMETRAVEL_H
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#define _UAPI_LINUX_UM_TIMETRAVEL_H
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#include <linux/types.h>
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/**
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 * struct um_timetravel_msg - UM time travel message
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 *
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 * This is the basic message type, going in both directions.
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 *
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 * This is the message passed between the host (user-mode Linux instance)
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 * and the calendar (the application on the other side of the socket) in
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 * order to implement common scheduling.
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 *
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 * Whenever UML has an event it will request runtime for it from the
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 * calendar, and then wait for its turn until it can run, etc. Note
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 * that it will only ever request the single next runtime, i.e. multiple
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 * REQUEST messages override each other.
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 */
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struct um_timetravel_msg {
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	/**
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	 * @op: operation value from &enum um_timetravel_ops
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	 */
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	__u32 op;
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	/**
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	 * @seq: sequence number for the message - shall be reflected in
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	 *	the ACK response, and should be checked while processing
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	 *	the response to see if it matches
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	 */
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	__u32 seq;
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	/**
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	 * @time: time in nanoseconds
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	 */
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	__u64 time;
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};
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/**
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 * enum um_timetravel_ops - Operation codes
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 */
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enum um_timetravel_ops {
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	/**
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	 * @UM_TIMETRAVEL_ACK: response (ACK) to any previous message,
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	 *	this usually doesn't carry any data in the 'time' field
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	 *	unless otherwise specified below
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	 */
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	UM_TIMETRAVEL_ACK		= 0,
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	/**
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	 * @UM_TIMETRAVEL_START: initialize the connection, the time
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	 *	field contains an (arbitrary) ID to possibly be able
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	 *	to distinguish the connections.
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	 */
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	UM_TIMETRAVEL_START		= 1,
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	/**
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	 * @UM_TIMETRAVEL_REQUEST: request to run at the given time
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	 *	(host -> calendar)
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	 */
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	UM_TIMETRAVEL_REQUEST		= 2,
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	/**
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	 * @UM_TIMETRAVEL_WAIT: Indicate waiting for the previously requested
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	 *	runtime, new requests may be made while waiting (e.g. due to
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	 *	interrupts); the time field is ignored. The calendar must process
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	 *	this message and later	send a %UM_TIMETRAVEL_RUN message when
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	 *	the host can run again.
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	 *	(host -> calendar)
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	 */
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	UM_TIMETRAVEL_WAIT		= 3,
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	/**
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	 * @UM_TIMETRAVEL_GET: return the current time from the calendar in the
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	 *	ACK message, the time in the request message is ignored
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	 *	(host -> calendar)
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	 */
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	UM_TIMETRAVEL_GET		= 4,
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	/**
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	 * @UM_TIMETRAVEL_UPDATE: time update to the calendar, must be sent e.g.
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	 *	before kicking an interrupt to another calendar
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	 *	(host -> calendar)
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	 */
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	UM_TIMETRAVEL_UPDATE		= 5,
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	/**
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	 * @UM_TIMETRAVEL_RUN: run time request granted, current time is in
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	 *	the time field
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	 *	(calendar -> host)
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	 */
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	UM_TIMETRAVEL_RUN		= 6,
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	/**
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	 * @UM_TIMETRAVEL_FREE_UNTIL: Enable free-running until the given time,
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	 *	this is a message from the calendar telling the host that it can
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	 *	freely do its own scheduling for anything before the indicated
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	 *	time.
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	 *	Note that if a calendar sends this message once, the host may
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	 *	assume that it will also do so in the future, if it implements
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	 *	wraparound semantics for the time field.
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	 *	(calendar -> host)
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	 */
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	UM_TIMETRAVEL_FREE_UNTIL	= 7,
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	/**
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	 * @UM_TIMETRAVEL_GET_TOD: Return time of day, typically used once at
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	 *	boot by the virtual machines to get a synchronized time from
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	 *	the simulation.
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	 */
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	UM_TIMETRAVEL_GET_TOD		= 8,
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};
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#endif /* _UAPI_LINUX_UM_TIMETRAVEL_H */
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