Dr. David Alan Gilbert | eb59db5 | 2015-11-05 18:10:55 +0000 | [diff] [blame] | 1 | /* |
| 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 Perevalov | d7651f1 | 2017-09-19 19:47:56 +0300 | [diff] [blame] | 17 | bool postcopy_ram_supported_by_host(MigrationIncomingState *mis); |
Dr. David Alan Gilbert | eb59db5 | 2015-11-05 18:10:55 +0000 | [diff] [blame] | 18 | |
Dr. David Alan Gilbert | e0b266f | 2015-11-05 18:11:02 +0000 | [diff] [blame] | 19 | /* |
Dr. David Alan Gilbert | f0a227a | 2015-11-05 18:11:04 +0000 | [diff] [blame] | 20 | * 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 | */ |
Wei Yang | 2a7eb14 | 2019-10-10 09:13:15 +0800 | [diff] [blame] | 23 | int postcopy_ram_incoming_setup(MigrationIncomingState *mis); |
Dr. David Alan Gilbert | f0a227a | 2015-11-05 18:11:04 +0000 | [diff] [blame] | 24 | |
| 25 | /* |
Dr. David Alan Gilbert | 1caddf8 | 2015-11-05 18:11:03 +0000 | [diff] [blame] | 26 | * 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 | */ |
David Hildenbrand | c136180 | 2018-06-20 22:27:36 +0200 | [diff] [blame] | 30 | int postcopy_ram_incoming_init(MigrationIncomingState *mis); |
Dr. David Alan Gilbert | 1caddf8 | 2015-11-05 18:11:03 +0000 | [diff] [blame] | 31 | |
| 32 | /* |
| 33 | * At the end of a migration where postcopy_ram_incoming_init was called. |
| 34 | */ |
| 35 | int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis); |
| 36 | |
| 37 | /* |
Dr. David Alan Gilbert | f952710 | 2015-11-05 18:11:20 +0000 | [diff] [blame] | 38 | * 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 | */ |
| 42 | int postcopy_ram_prepare_discard(MigrationIncomingState *mis); |
Dr. David Alan Gilbert | e0b266f | 2015-11-05 18:11:02 +0000 | [diff] [blame] | 43 | |
| 44 | /* |
| 45 | * Called at the start of each RAMBlock by the bitmap code. |
Dr. David Alan Gilbert | e0b266f | 2015-11-05 18:11:02 +0000 | [diff] [blame] | 46 | */ |
Wei Yang | 810cf2b | 2019-07-24 09:07:21 +0800 | [diff] [blame] | 47 | void postcopy_discard_send_init(MigrationState *ms, const char *name); |
Dr. David Alan Gilbert | e0b266f | 2015-11-05 18:11:02 +0000 | [diff] [blame] | 48 | |
| 49 | /* |
| 50 | * Called by the bitmap code for each chunk to discard. |
| 51 | * May send a discard message, may just leave it queued to |
| 52 | * be sent later. |
| 53 | * @start,@length: a range of pages in the migration bitmap in the |
| 54 | * RAM block passed to postcopy_discard_send_init() (length=1 is one page) |
| 55 | */ |
Wei Yang | 810cf2b | 2019-07-24 09:07:21 +0800 | [diff] [blame] | 56 | void postcopy_discard_send_range(MigrationState *ms, unsigned long start, |
| 57 | unsigned long length); |
Dr. David Alan Gilbert | e0b266f | 2015-11-05 18:11:02 +0000 | [diff] [blame] | 58 | |
| 59 | /* |
| 60 | * Called at the end of each RAMBlock by the bitmap code. |
Wei Yang | 810cf2b | 2019-07-24 09:07:21 +0800 | [diff] [blame] | 61 | * Sends any outstanding discard messages. |
Dr. David Alan Gilbert | e0b266f | 2015-11-05 18:11:02 +0000 | [diff] [blame] | 62 | */ |
Wei Yang | 810cf2b | 2019-07-24 09:07:21 +0800 | [diff] [blame] | 63 | void postcopy_discard_send_finish(MigrationState *ms); |
Dr. David Alan Gilbert | e0b266f | 2015-11-05 18:11:02 +0000 | [diff] [blame] | 64 | |
Dr. David Alan Gilbert | 696ed9a | 2015-11-05 18:11:10 +0000 | [diff] [blame] | 65 | /* |
| 66 | * Place a page (from) at (host) efficiently |
| 67 | * There are restrictions on how 'from' must be mapped, in general best |
| 68 | * to use other postcopy_ routines to allocate. |
| 69 | * returns 0 on success |
| 70 | */ |
Dr. David Alan Gilbert | df9ff5e | 2017-02-24 18:28:35 +0000 | [diff] [blame] | 71 | int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from, |
Alexey Perevalov | 8be4620 | 2017-10-05 14:13:18 +0300 | [diff] [blame] | 72 | RAMBlock *rb); |
Dr. David Alan Gilbert | 696ed9a | 2015-11-05 18:11:10 +0000 | [diff] [blame] | 73 | |
| 74 | /* |
| 75 | * Place a zero page at (host) atomically |
| 76 | * returns 0 on success |
| 77 | */ |
Dr. David Alan Gilbert | df9ff5e | 2017-02-24 18:28:35 +0000 | [diff] [blame] | 78 | int postcopy_place_page_zero(MigrationIncomingState *mis, void *host, |
Alexey Perevalov | 8be4620 | 2017-10-05 14:13:18 +0300 | [diff] [blame] | 79 | RAMBlock *rb); |
Dr. David Alan Gilbert | 696ed9a | 2015-11-05 18:11:10 +0000 | [diff] [blame] | 80 | |
Juan Quintela | bac3b21 | 2017-04-24 16:50:35 +0200 | [diff] [blame] | 81 | /* The current postcopy state is read/set by postcopy_state_get/set |
| 82 | * which update it atomically. |
| 83 | * The state is updated as postcopy messages are received, and |
| 84 | * in general only one thread should be writing to the state at any one |
| 85 | * time, initially the main thread and then the listen thread; |
| 86 | * Corner cases are where either thread finishes early and/or errors. |
| 87 | * The state is checked as messages are received to ensure that |
| 88 | * the source is sending us messages in the correct order. |
| 89 | * The state is also used by the RAM reception code to know if it |
| 90 | * has to place pages atomically, and the cleanup code at the end of |
| 91 | * the main thread to know if it has to delay cleanup until the end |
| 92 | * of postcopy. |
| 93 | */ |
| 94 | typedef enum { |
| 95 | POSTCOPY_INCOMING_NONE = 0, /* Initial state - no postcopy */ |
| 96 | POSTCOPY_INCOMING_ADVISE, |
| 97 | POSTCOPY_INCOMING_DISCARD, |
| 98 | POSTCOPY_INCOMING_LISTENING, |
| 99 | POSTCOPY_INCOMING_RUNNING, |
| 100 | POSTCOPY_INCOMING_END |
| 101 | } PostcopyState; |
| 102 | |
Juan Quintela | bac3b21 | 2017-04-24 16:50:35 +0200 | [diff] [blame] | 103 | PostcopyState postcopy_state_get(void); |
| 104 | /* Set the state and return the old state */ |
| 105 | PostcopyState postcopy_state_set(PostcopyState new_state); |
| 106 | |
Peter Xu | 9ab7ef9 | 2018-02-08 18:31:07 +0800 | [diff] [blame] | 107 | void postcopy_fault_thread_notify(MigrationIncomingState *mis); |
| 108 | |
Dr. David Alan Gilbert | 1693c64 | 2018-03-12 17:20:59 +0000 | [diff] [blame] | 109 | /* |
| 110 | * To be called once at the start before any device initialisation |
| 111 | */ |
| 112 | void postcopy_infrastructure_init(void); |
| 113 | |
| 114 | /* Add a notifier to a list to be called when checking whether the devices |
| 115 | * can support postcopy. |
| 116 | * It's data is a *PostcopyNotifyData |
| 117 | * It should return 0 if OK, or a negative value on failure. |
| 118 | * On failure it must set the data->errp to an error. |
| 119 | * |
| 120 | */ |
| 121 | enum PostcopyNotifyReason { |
| 122 | POSTCOPY_NOTIFY_PROBE = 0, |
Dr. David Alan Gilbert | d3dff7a | 2018-03-12 17:21:01 +0000 | [diff] [blame] | 123 | POSTCOPY_NOTIFY_INBOUND_ADVISE, |
Dr. David Alan Gilbert | 6864a7b | 2018-03-12 17:21:06 +0000 | [diff] [blame] | 124 | POSTCOPY_NOTIFY_INBOUND_LISTEN, |
Dr. David Alan Gilbert | 4634357 | 2018-03-12 17:21:20 +0000 | [diff] [blame] | 125 | POSTCOPY_NOTIFY_INBOUND_END, |
Dr. David Alan Gilbert | 1693c64 | 2018-03-12 17:20:59 +0000 | [diff] [blame] | 126 | }; |
| 127 | |
| 128 | struct PostcopyNotifyData { |
| 129 | enum PostcopyNotifyReason reason; |
| 130 | Error **errp; |
| 131 | }; |
| 132 | |
| 133 | void postcopy_add_notifier(NotifierWithReturn *nn); |
| 134 | void postcopy_remove_notifier(NotifierWithReturn *n); |
| 135 | /* Call the notifier list set by postcopy_add_start_notifier */ |
| 136 | int postcopy_notify(enum PostcopyNotifyReason reason, Error **errp); |
| 137 | |
Dr. David Alan Gilbert | 00fa4fc | 2018-03-12 17:21:04 +0000 | [diff] [blame] | 138 | struct PostCopyFD; |
| 139 | |
| 140 | /* ufd is a pointer to the struct uffd_msg *TODO: more Portable! */ |
| 141 | typedef int (*pcfdhandler)(struct PostCopyFD *pcfd, void *ufd); |
Dr. David Alan Gilbert | d488b34 | 2018-03-12 17:21:15 +0000 | [diff] [blame] | 142 | /* Notification to wake, either on place or on reception of |
| 143 | * a fault on something that's already arrived (race) |
| 144 | */ |
| 145 | typedef int (*pcfdwake)(struct PostCopyFD *pcfd, RAMBlock *rb, uint64_t offset); |
Dr. David Alan Gilbert | 00fa4fc | 2018-03-12 17:21:04 +0000 | [diff] [blame] | 146 | |
| 147 | struct PostCopyFD { |
| 148 | int fd; |
| 149 | /* Data to pass to handler */ |
| 150 | void *data; |
| 151 | /* Handler to be called whenever we get a poll event */ |
| 152 | pcfdhandler handler; |
Dr. David Alan Gilbert | d488b34 | 2018-03-12 17:21:15 +0000 | [diff] [blame] | 153 | /* Notification to wake shared client */ |
| 154 | pcfdwake waker; |
Dr. David Alan Gilbert | 00fa4fc | 2018-03-12 17:21:04 +0000 | [diff] [blame] | 155 | /* A string to use in error messages */ |
| 156 | const char *idstr; |
| 157 | }; |
| 158 | |
| 159 | /* Register a userfaultfd owned by an external process for |
| 160 | * shared memory. |
| 161 | */ |
| 162 | void postcopy_register_shared_ufd(struct PostCopyFD *pcfd); |
| 163 | void postcopy_unregister_shared_ufd(struct PostCopyFD *pcfd); |
zhaolichang | 3a4452d | 2020-09-17 15:50:21 +0800 | [diff] [blame] | 164 | /* Call each of the shared 'waker's registered telling them of |
Dr. David Alan Gilbert | d488b34 | 2018-03-12 17:21:15 +0000 | [diff] [blame] | 165 | * availability of a block. |
| 166 | */ |
| 167 | int postcopy_notify_shared_wake(RAMBlock *rb, uint64_t offset); |
Dr. David Alan Gilbert | 5efc356 | 2018-03-12 17:21:14 +0000 | [diff] [blame] | 168 | /* postcopy_wake_shared: Notify a client ufd that a page is available |
| 169 | * |
| 170 | * Returns 0 on success |
| 171 | * |
| 172 | * @pcfd: Structure with fd, handler and name as above |
| 173 | * @client_addr: Address in the client program, not QEMU |
| 174 | * @rb: The RAMBlock the page is in |
| 175 | */ |
| 176 | int postcopy_wake_shared(struct PostCopyFD *pcfd, uint64_t client_addr, |
| 177 | RAMBlock *rb); |
Dr. David Alan Gilbert | 096bf4c | 2018-03-12 17:21:12 +0000 | [diff] [blame] | 178 | /* Callback from shared fault handlers to ask for a page */ |
| 179 | int postcopy_request_shared_page(struct PostCopyFD *pcfd, RAMBlock *rb, |
| 180 | uint64_t client_addr, uint64_t offset); |
Dr. David Alan Gilbert | 00fa4fc | 2018-03-12 17:21:04 +0000 | [diff] [blame] | 181 | |
Dr. David Alan Gilbert | eb59db5 | 2015-11-05 18:10:55 +0000 | [diff] [blame] | 182 | #endif |