/* * Postcopy migration for RAM * * Copyright 2013 Red Hat, Inc. and/or its affiliates * * Authors: * Dave Gilbert * * 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