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Dr. David Alan Gilberteb59db52015-11-05 18:10:55 +00001/*
2 * Postcopy migration for RAM
3 *
4 * Copyright 2013 Red Hat, Inc. and/or its affiliates
5 *
6 * Authors:
7 * Dave Gilbert <dgilbert@redhat.com>
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2 or later.
10 * See the COPYING file in the top-level directory.
11 *
12 */
13#ifndef QEMU_POSTCOPY_RAM_H
14#define QEMU_POSTCOPY_RAM_H
15
16/* Return true if the host supports everything we need to do postcopy-ram */
Alexey Perevalovd7651f12017-09-19 19:47:56 +030017bool postcopy_ram_supported_by_host(MigrationIncomingState *mis);
Dr. David Alan Gilberteb59db52015-11-05 18:10:55 +000018
Dr. David Alan Gilberte0b266f2015-11-05 18:11:02 +000019/*
Dr. David Alan Gilbertf0a227a2015-11-05 18:11:04 +000020 * Make all of RAM sensitive to accesses to areas that haven't yet been written
21 * and wire up anything necessary to deal with it.
22 */
23int postcopy_ram_enable_notify(MigrationIncomingState *mis);
24
25/*
Dr. David Alan Gilbert1caddf82015-11-05 18:11:03 +000026 * Initialise postcopy-ram, setting the RAM to a state where we can go into
27 * postcopy later; must be called prior to any precopy.
28 * called from ram.c's similarly named ram_postcopy_incoming_init
29 */
30int postcopy_ram_incoming_init(MigrationIncomingState *mis, size_t ram_pages);
31
32/*
33 * At the end of a migration where postcopy_ram_incoming_init was called.
34 */
35int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis);
36
37/*
Dr. David Alan Gilbertf9527102015-11-05 18:11:20 +000038 * Userfault requires us to mark RAM as NOHUGEPAGE prior to discard
39 * however leaving it until after precopy means that most of the precopy
40 * data is still THPd
41 */
42int postcopy_ram_prepare_discard(MigrationIncomingState *mis);
Dr. David Alan Gilberte0b266f2015-11-05 18:11:02 +000043
44/*
45 * Called at the start of each RAMBlock by the bitmap code.
Dr. David Alan Gilberte0b266f2015-11-05 18:11:02 +000046 * Returns a new PDS
47 */
48PostcopyDiscardState *postcopy_discard_send_init(MigrationState *ms,
Dr. David Alan Gilberte0b266f2015-11-05 18:11:02 +000049 const char *name);
50
51/*
52 * Called by the bitmap code for each chunk to discard.
53 * May send a discard message, may just leave it queued to
54 * be sent later.
55 * @start,@length: a range of pages in the migration bitmap in the
56 * RAM block passed to postcopy_discard_send_init() (length=1 is one page)
57 */
58void postcopy_discard_send_range(MigrationState *ms, PostcopyDiscardState *pds,
59 unsigned long start, unsigned long length);
60
61/*
62 * Called at the end of each RAMBlock by the bitmap code.
63 * Sends any outstanding discard messages, frees the PDS.
64 */
65void postcopy_discard_send_finish(MigrationState *ms,
66 PostcopyDiscardState *pds);
67
Dr. David Alan Gilbert696ed9a2015-11-05 18:11:10 +000068/*
69 * Place a page (from) at (host) efficiently
70 * There are restrictions on how 'from' must be mapped, in general best
71 * to use other postcopy_ routines to allocate.
72 * returns 0 on success
73 */
Dr. David Alan Gilbertdf9ff5e2017-02-24 18:28:35 +000074int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from,
Alexey Perevalov8be46202017-10-05 14:13:18 +030075 RAMBlock *rb);
Dr. David Alan Gilbert696ed9a2015-11-05 18:11:10 +000076
77/*
78 * Place a zero page at (host) atomically
79 * returns 0 on success
80 */
Dr. David Alan Gilbertdf9ff5e2017-02-24 18:28:35 +000081int postcopy_place_page_zero(MigrationIncomingState *mis, void *host,
Alexey Perevalov8be46202017-10-05 14:13:18 +030082 RAMBlock *rb);
Dr. David Alan Gilbert696ed9a2015-11-05 18:11:10 +000083
Juan Quintelabac3b212017-04-24 16:50:35 +020084/* The current postcopy state is read/set by postcopy_state_get/set
85 * which update it atomically.
86 * The state is updated as postcopy messages are received, and
87 * in general only one thread should be writing to the state at any one
88 * time, initially the main thread and then the listen thread;
89 * Corner cases are where either thread finishes early and/or errors.
90 * The state is checked as messages are received to ensure that
91 * the source is sending us messages in the correct order.
92 * The state is also used by the RAM reception code to know if it
93 * has to place pages atomically, and the cleanup code at the end of
94 * the main thread to know if it has to delay cleanup until the end
95 * of postcopy.
96 */
97typedef enum {
98 POSTCOPY_INCOMING_NONE = 0, /* Initial state - no postcopy */
99 POSTCOPY_INCOMING_ADVISE,
100 POSTCOPY_INCOMING_DISCARD,
101 POSTCOPY_INCOMING_LISTENING,
102 POSTCOPY_INCOMING_RUNNING,
103 POSTCOPY_INCOMING_END
104} PostcopyState;
105
Dr. David Alan Gilbert696ed9a2015-11-05 18:11:10 +0000106/*
107 * Allocate a page of memory that can be mapped at a later point in time
108 * using postcopy_place_page
109 * Returns: Pointer to allocated page
110 */
111void *postcopy_get_tmp_page(MigrationIncomingState *mis);
112
Juan Quintelabac3b212017-04-24 16:50:35 +0200113PostcopyState postcopy_state_get(void);
114/* Set the state and return the old state */
115PostcopyState postcopy_state_set(PostcopyState new_state);
116
Peter Xu9ab7ef92018-02-08 18:31:07 +0800117void postcopy_fault_thread_notify(MigrationIncomingState *mis);
118
Dr. David Alan Gilberteb59db52015-11-05 18:10:55 +0000119#endif