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 "qapi/error.h"
  19#include "qapi/qapi-commands-migration.h"
  20#include "qapi/qmp/qerror.h"
  21#include "qemu/error-report.h"
  22#include "trace.h"
  23
  24static QEMUBH *failover_bh;
  25static FailoverStatus failover_state;
  26
  27static void colo_failover_bh(void *opaque)
  28{
  29    int old_state;
  30
  31    qemu_bh_delete(failover_bh);
  32    failover_bh = NULL;
  33
  34    old_state = failover_set_state(FAILOVER_STATUS_REQUIRE,
  35                                   FAILOVER_STATUS_ACTIVE);
  36    if (old_state != FAILOVER_STATUS_REQUIRE) {
  37        error_report("Unknown error for failover, old_state = %s",
  38                    FailoverStatus_str(old_state));
  39        return;
  40    }
  41
  42    colo_do_failover();
  43}
  44
  45void failover_request_active(Error **errp)
  46{
  47   if (failover_set_state(FAILOVER_STATUS_NONE,
  48        FAILOVER_STATUS_REQUIRE) != FAILOVER_STATUS_NONE) {
  49        error_setg(errp, "COLO failover is already activated");
  50        return;
  51    }
  52    failover_bh = qemu_bh_new(colo_failover_bh, NULL);
  53    qemu_bh_schedule(failover_bh);
  54}
  55
  56void failover_init_state(void)
  57{
  58    failover_state = FAILOVER_STATUS_NONE;
  59}
  60
  61FailoverStatus failover_set_state(FailoverStatus old_state,
  62                    FailoverStatus new_state)
  63{
  64    FailoverStatus old;
  65
  66    old = qatomic_cmpxchg(&failover_state, old_state, new_state);
  67    if (old == old_state) {
  68        trace_colo_failover_set_state(FailoverStatus_str(new_state));
  69    }
  70    return old;
  71}
  72
  73FailoverStatus failover_get_state(void)
  74{
  75    return qatomic_read(&failover_state);
  76}
  77
  78void qmp_x_colo_lost_heartbeat(Error **errp)
  79{
  80    if (get_colo_mode() == COLO_MODE_NONE) {
  81        error_setg(errp, QERR_FEATURE_DISABLED, "colo");
  82        return;
  83    }
  84
  85    failover_request_active(errp);
  86}
  87