/*
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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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