Merge remote-tracking branch 'remotes/dgilbert/tags/pull-migration-20200925a' into...
[qemu.git] / migration / page_cache.h
1 /*
2 * Page cache for QEMU
3 * The cache is base on a hash of the page address
4 *
5 * Copyright 2012 Red Hat, Inc. and/or its affiliates
6 *
7 * Authors:
8 * Orit Wasserman <owasserm@redhat.com>
9 *
10 * This work is licensed under the terms of the GNU GPL, version 2 or later.
11 * See the COPYING file in the top-level directory.
12 *
13 */
14
15 #ifndef PAGE_CACHE_H
16 #define PAGE_CACHE_H
17
18 /* Page cache for storing guest pages */
19 typedef struct PageCache PageCache;
20
21 /**
22 * cache_init: Initialize the page cache
23 *
24 *
25 * Returns new allocated cache or NULL on error
26 *
27 * @cache_size: cache size in bytes
28 * @page_size: cache page size
29 * @errp: set *errp if the check failed, with reason
30 */
31 PageCache *cache_init(int64_t cache_size, size_t page_size, Error **errp);
32 /**
33 * cache_fini: free all cache resources
34 * @cache pointer to the PageCache struct
35 */
36 void cache_fini(PageCache *cache);
37
38 /**
39 * cache_is_cached: Checks to see if the page is cached
40 *
41 * Returns %true if page is cached
42 *
43 * @cache pointer to the PageCache struct
44 * @addr: page addr
45 * @current_age: current bitmap generation
46 */
47 bool cache_is_cached(const PageCache *cache, uint64_t addr,
48 uint64_t current_age);
49
50 /**
51 * get_cached_data: Get the data cached for an addr
52 *
53 * Returns pointer to the data cached or NULL if not cached
54 *
55 * @cache pointer to the PageCache struct
56 * @addr: page addr
57 */
58 uint8_t *get_cached_data(const PageCache *cache, uint64_t addr);
59
60 /**
61 * cache_insert: insert the page into the cache. the page cache
62 * will dup the data on insert. the previous value will be overwritten
63 *
64 * Returns -1 when the page isn't inserted into cache
65 *
66 * @cache pointer to the PageCache struct
67 * @addr: page address
68 * @pdata: pointer to the page
69 * @current_age: current bitmap generation
70 */
71 int cache_insert(PageCache *cache, uint64_t addr, const uint8_t *pdata,
72 uint64_t current_age);
73
74 #endif