include/exec/ramblock.h

   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