LXR qemu/migration/colo-failover.c

   1/*
   2 * COarse-grain LOck-stepping Virtual Machines for Non-stop Service (COLO)
   3 * (a.k.a. Fault Tolerance or Continuous Replication)
   4 *
   5 * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
   6 * Copyright (c) 2016 FUJITSU LIMITED
   7 * Copyright (c) 2016 Intel Corporation
   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#include "qemu/osdep.h"
  14#include "migration/colo.h"
  15#include "migration/failover.h"
  16#include "qemu/main-loop.h"
  17#include "migration.h"
  18#include "qmp-commands.h"
  19#include "qapi/qmp/qerror.h"
  20#include "qemu/error-report.h"
  21#include "trace.h"
  22
  23static QEMUBH *failover_bh;
  24static FailoverStatus failover_state;
  25
  26static void colo_failover_bh(void *opaque)
  27{
  28    int old_state;
  29
  30    qemu_bh_delete(failover_bh);
  31    failover_bh = NULL;
  32
  33    old_state = failover_set_state(FAILOVER_STATUS_REQUIRE,
  34                                   FAILOVER_STATUS_ACTIVE);
  35    if (old_state != FAILOVER_STATUS_REQUIRE) {
  36        error_report("Unknown error for failover, old_state = %s",
  37                    FailoverStatus_lookup[old_state]);
  38        return;
  39    }
  40
  41    colo_do_failover(NULL);
  42}
  43
  44void failover_request_active(Error **errp)
  45{
  46   if (failover_set_state(FAILOVER_STATUS_NONE,
  47        FAILOVER_STATUS_REQUIRE) != FAILOVER_STATUS_NONE) {
  48        error_setg(errp, "COLO failover is already actived");
  49        return;
  50    }
  51    failover_bh = qemu_bh_new(colo_failover_bh, NULL);
  52    qemu_bh_schedule(failover_bh);
  53}
  54
  55void failover_init_state(void)
  56{
  57    failover_state = FAILOVER_STATUS_NONE;
  58}
  59
  60FailoverStatus failover_set_state(FailoverStatus old_state,
  61                    FailoverStatus new_state)
  62{
  63    FailoverStatus old;
  64
  65    old = atomic_cmpxchg(&failover_state, old_state, new_state);
  66    if (old == old_state) {
  67        trace_colo_failover_set_state(FailoverStatus_lookup[new_state]);
  68    }
  69    return old;
  70}
  71
  72FailoverStatus failover_get_state(void)
  73{
  74    return atomic_read(&failover_state);
  75}
  76
  77void qmp_x_colo_lost_heartbeat(Error **errp)
  78{
  79    if (get_colo_mode() == COLO_MODE_UNKNOWN) {
  80        error_setg(errp, QERR_FEATURE_DISABLED, "colo");
  81        return;
  82    }
  83
  84    failover_request_active(errp);
  85}
  86