LXR qemu/migration/global

   1/*
   2 * Global State configuration
   3 *
   4 * Copyright (c) 2014-2017 Red Hat Inc
   5 *
   6 * Authors:
   7 *  Juan Quintela <quintela@redhat.com>
   8 *
   9 * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10 * See the COPYING file in the top-level directory.
  11 */
  12
  13#include "qemu/osdep.h"
  14#include "qemu/cutils.h"
  15#include "qemu/error-report.h"
  16#include "system/runstate.h"
  17#include "qapi/error.h"
  18#include "migration.h"
  19#include "migration/global_state.h"
  20#include "migration/vmstate.h"
  21#include "trace.h"
  22
  23typedef struct {
  24    uint32_t size;
  25
  26    /*
  27     * runstate was 100 bytes, zero padded, but we trimmed it to add a
  28     * few fields and maintain backwards compatibility.
  29     */
  30    uint8_t runstate[32];
  31    uint8_t has_vm_was_suspended;
  32    uint8_t vm_was_suspended;
  33    uint8_t unused[66];
  34
  35    RunState state;
  36    bool received;
  37} GlobalState;
  38
  39static GlobalState global_state;
  40
  41static void global_state_do_store(RunState state)
  42{
  43    const char *state_str = RunState_str(state);
  44    assert(strlen(state_str) < sizeof(global_state.runstate));
  45    strpadcpy((char *)global_state.runstate, sizeof(global_state.runstate),
  46              state_str, '\0');
  47    global_state.has_vm_was_suspended = true;
  48    global_state.vm_was_suspended = vm_get_suspended();
  49
  50    memset(global_state.unused, 0, sizeof(global_state.unused));
  51}
  52
  53void global_state_store(void)
  54{
  55    global_state_do_store(runstate_get());
  56}
  57
  58void global_state_store_running(void)
  59{
  60    global_state_do_store(RUN_STATE_RUNNING);
  61}
  62
  63bool global_state_received(void)
  64{
  65    return global_state.received;
  66}
  67
  68RunState global_state_get_runstate(void)
  69{
  70    return global_state.state;
  71}
  72
  73static bool global_state_needed(void *opaque)
  74{
  75    return migrate_get_current()->store_global_state;
  76}
  77
  78static int global_state_post_load(void *opaque, int version_id)
  79{
  80    GlobalState *s = opaque;
  81    Error *local_err = NULL;
  82    int r;
  83    char *runstate = (char *)s->runstate;
  84
  85    s->received = true;
  86    trace_migrate_global_state_post_load(runstate);
  87
  88    if (strnlen((char *)s->runstate,
  89                sizeof(s->runstate)) == sizeof(s->runstate)) {
  90        /*
  91         * This condition should never happen during migration, because
  92         * all runstate names are shorter than 32 bytes (the size of
  93         * s->runstate). However, a malicious stream could overflow
  94         * the qapi_enum_parse() call, so we force the last character
  95         * to a NUL byte.
  96         */
  97        s->runstate[sizeof(s->runstate) - 1] = '\0';
  98    }
  99    r = qapi_enum_parse(&RunState_lookup, runstate, -1, &local_err);
 100
 101    if (r == -1) {
 102        if (local_err) {
 103            error_report_err(local_err);
 104        }
 105        return -EINVAL;
 106    }
 107    s->state = r;
 108
 109    /*
 110     * global_state is saved on the outgoing side before forcing a stopped
 111     * state, so it may have saved state=suspended and vm_was_suspended=0.
 112     * Now we are in a paused state, and when we later call vm_start, it must
 113     * restore the suspended state, so we must set vm_was_suspended=1 here.
 114     */
 115    vm_set_suspended(s->vm_was_suspended || r == RUN_STATE_SUSPENDED);
 116
 117    return 0;
 118}
 119
 120static int global_state_pre_save(void *opaque)
 121{
 122    GlobalState *s = opaque;
 123
 124    trace_migrate_global_state_pre_save((char *)s->runstate);
 125    s->size = strnlen((char *)s->runstate, sizeof(s->runstate)) + 1;
 126    assert(s->size <= sizeof(s->runstate));
 127
 128    return 0;
 129}
 130
 131static const VMStateDescription vmstate_globalstate = {
 132    .name = "globalstate",
 133    .version_id = 1,
 134    .minimum_version_id = 1,
 135    .post_load = global_state_post_load,
 136    .pre_save = global_state_pre_save,
 137    .needed = global_state_needed,
 138    .fields = (const VMStateField[]) {
 139        VMSTATE_UINT32(size, GlobalState),
 140        VMSTATE_BUFFER(runstate, GlobalState),
 141        VMSTATE_UINT8(has_vm_was_suspended, GlobalState),
 142        VMSTATE_UINT8(vm_was_suspended, GlobalState),
 143        VMSTATE_BUFFER(unused, GlobalState),
 144        VMSTATE_END_OF_LIST()
 145    },
 146};
 147
 148void register_global_state(void)
 149{
 150    /* We would use it independently that we receive it */
 151    strcpy((char *)&global_state.runstate, "");
 152    global_state.received = false;
 153    vmstate_register(NULL, 0, &vmstate_globalstate, &global_state);
 154}
 155