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