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Diffstat (limited to 'qemu/include/migration/postcopy-ram.h')
-rw-r--r-- | qemu/include/migration/postcopy-ram.h | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/qemu/include/migration/postcopy-ram.h b/qemu/include/migration/postcopy-ram.h new file mode 100644 index 000000000..b6a7491f2 --- /dev/null +++ b/qemu/include/migration/postcopy-ram.h @@ -0,0 +1,99 @@ +/* + * Postcopy migration for RAM + * + * Copyright 2013 Red Hat, Inc. and/or its affiliates + * + * Authors: + * Dave Gilbert <dgilbert@redhat.com> + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + * + */ +#ifndef QEMU_POSTCOPY_RAM_H +#define QEMU_POSTCOPY_RAM_H + +/* Return true if the host supports everything we need to do postcopy-ram */ +bool postcopy_ram_supported_by_host(void); + +/* + * Make all of RAM sensitive to accesses to areas that haven't yet been written + * and wire up anything necessary to deal with it. + */ +int postcopy_ram_enable_notify(MigrationIncomingState *mis); + +/* + * Initialise postcopy-ram, setting the RAM to a state where we can go into + * postcopy later; must be called prior to any precopy. + * called from ram.c's similarly named ram_postcopy_incoming_init + */ +int postcopy_ram_incoming_init(MigrationIncomingState *mis, size_t ram_pages); + +/* + * At the end of a migration where postcopy_ram_incoming_init was called. + */ +int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis); + +/* + * Discard the contents of 'length' bytes from 'start' + * We can assume that if we've been called postcopy_ram_hosttest returned true + */ +int postcopy_ram_discard_range(MigrationIncomingState *mis, uint8_t *start, + size_t length); + +/* + * Userfault requires us to mark RAM as NOHUGEPAGE prior to discard + * however leaving it until after precopy means that most of the precopy + * data is still THPd + */ +int postcopy_ram_prepare_discard(MigrationIncomingState *mis); + +/* + * Called at the start of each RAMBlock by the bitmap code. + * 'offset' is the bitmap offset of the named RAMBlock in the migration + * bitmap. + * Returns a new PDS + */ +PostcopyDiscardState *postcopy_discard_send_init(MigrationState *ms, + unsigned long offset, + const char *name); + +/* + * Called by the bitmap code for each chunk to discard. + * May send a discard message, may just leave it queued to + * be sent later. + * @start,@length: a range of pages in the migration bitmap in the + * RAM block passed to postcopy_discard_send_init() (length=1 is one page) + */ +void postcopy_discard_send_range(MigrationState *ms, PostcopyDiscardState *pds, + unsigned long start, unsigned long length); + +/* + * Called at the end of each RAMBlock by the bitmap code. + * Sends any outstanding discard messages, frees the PDS. + */ +void postcopy_discard_send_finish(MigrationState *ms, + PostcopyDiscardState *pds); + +/* + * Place a page (from) at (host) efficiently + * There are restrictions on how 'from' must be mapped, in general best + * to use other postcopy_ routines to allocate. + * returns 0 on success + */ +int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from); + +/* + * Place a zero page at (host) atomically + * returns 0 on success + */ +int postcopy_place_page_zero(MigrationIncomingState *mis, void *host); + +/* + * Allocate a page of memory that can be mapped at a later point in time + * using postcopy_place_page + * Returns: Pointer to allocated page + */ +void *postcopy_get_tmp_page(MigrationIncomingState *mis); + +#endif |