xref: /openbmc/qemu/include/exec/ramblock.h (revision b91a0fa7)
1 /*
2  * Declarations for cpu physical memory functions
3  *
4  * Copyright 2011 Red Hat, Inc. and/or its affiliates
5  *
6  * Authors:
7  *  Avi Kivity <avi@redhat.com>
8  *
9  * This work is licensed under the terms of the GNU GPL, version 2 or
10  * later.  See the COPYING file in the top-level directory.
11  *
12  */
13 
14 /*
15  * This header is for use by exec.c and memory.c ONLY.  Do not include it.
16  * The functions declared here will be removed soon.
17  */
18 
19 #ifndef QEMU_EXEC_RAMBLOCK_H
20 #define QEMU_EXEC_RAMBLOCK_H
21 
22 #ifndef CONFIG_USER_ONLY
23 #include "cpu-common.h"
24 
25 struct RAMBlock {
26     struct rcu_head rcu;
27     struct MemoryRegion *mr;
28     uint8_t *host;
29     uint8_t *colo_cache; /* For colo, VM's ram cache */
30     ram_addr_t offset;
31     ram_addr_t used_length;
32     ram_addr_t max_length;
33     void (*resized)(const char*, uint64_t length, void *host);
34     uint32_t flags;
35     /* Protected by iothread lock.  */
36     char idstr[256];
37     /* RCU-enabled, writes protected by the ramlist lock */
38     QLIST_ENTRY(RAMBlock) next;
39     QLIST_HEAD(, RAMBlockNotifier) ramblock_notifiers;
40     int fd;
41     size_t page_size;
42     /* dirty bitmap used during migration */
43     unsigned long *bmap;
44     /* bitmap of already received pages in postcopy */
45     unsigned long *receivedmap;
46 
47     /*
48      * bitmap to track already cleared dirty bitmap.  When the bit is
49      * set, it means the corresponding memory chunk needs a log-clear.
50      * Set this up to non-NULL to enable the capability to postpone
51      * and split clearing of dirty bitmap on the remote node (e.g.,
52      * KVM).  The bitmap will be set only when doing global sync.
53      *
54      * NOTE: this bitmap is different comparing to the other bitmaps
55      * in that one bit can represent multiple guest pages (which is
56      * decided by the `clear_bmap_shift' variable below).  On
57      * destination side, this should always be NULL, and the variable
58      * `clear_bmap_shift' is meaningless.
59      */
60     unsigned long *clear_bmap;
61     uint8_t clear_bmap_shift;
62 
63     /*
64      * RAM block length that corresponds to the used_length on the migration
65      * source (after RAM block sizes were synchronized). Especially, after
66      * starting to run the guest, used_length and postcopy_length can differ.
67      * Used to register/unregister uffd handlers and as the size of the received
68      * bitmap. Receiving any page beyond this length will bail out, as it
69      * could not have been valid on the source.
70      */
71     ram_addr_t postcopy_length;
72 };
73 #endif
74 #endif
75