Re: [Qemu-devel] [RFC PATCH v2 09/26] replay: save prior value of the host clock

[Paolo Bonzini]

On 14/11/2017 09:17, Pavel Dovgalyuk wrote:
> This patch adds saving/restoring of the host clock field 'last'.
> It is used in host clock calculation and therefore clock may
> become incorrect when using restored vmstate.
> 
> Signed-off-by: Pavel Dovgalyuk <address@hidden>
> 
> ---
>  include/qemu/timer.h     |   14 ++++++++++++++
>  replay/replay-internal.h |    2 ++
>  replay/replay-snapshot.c |    3 +++
>  util/qemu-timer.c        |   12 ++++++++++++
>  4 files changed, 31 insertions(+)
> 
> diff --git a/include/qemu/timer.h b/include/qemu/timer.h
> index 1b518bc..a610a17 100644
> --- a/include/qemu/timer.h
> +++ b/include/qemu/timer.h
> @@ -251,6 +251,20 @@ bool qemu_clock_run_timers(QEMUClockType type);
>   */
>  bool qemu_clock_run_all_timers(void);
>  
> +/**
> + * qemu_clock_get_last:
> + *
> + * Returns last clock query time.
> + */
> +uint64_t qemu_clock_get_last(QEMUClockType type);
> +/**
> + * qemu_clock_set_last:
> + *
> + * Sets last clock query time.
> + */
> +void qemu_clock_set_last(QEMUClockType type, uint64_t last);
> +
> +
>  /*
>   * QEMUTimerList
>   */
> diff --git a/replay/replay-internal.h b/replay/replay-internal.h
> index 3ebb199..be96d7e 100644
> --- a/replay/replay-internal.h
> +++ b/replay/replay-internal.h
> @@ -78,6 +78,8 @@ typedef struct ReplayState {
>          This counter is global, because requests from different
>          block devices should not get overlapping ids. */
>      uint64_t block_request_id;
> +    /*! Prior value of the host clock */
> +    uint64_t host_clock_last;
>  } ReplayState;
>  extern ReplayState replay_state;
>  
> diff --git a/replay/replay-snapshot.c b/replay/replay-snapshot.c
> index 7075986..e0b2204 100644
> --- a/replay/replay-snapshot.c
> +++ b/replay/replay-snapshot.c
> @@ -25,6 +25,7 @@ static int replay_pre_save(void *opaque)
>  {
>      ReplayState *state = opaque;
>      state->file_offset = ftell(replay_file);
> +    state->host_clock_last = qemu_clock_get_last(QEMU_CLOCK_HOST);
>  
>      return 0;
>  }
> @@ -33,6 +34,7 @@ static int replay_post_load(void *opaque, int version_id)
>  {
>      ReplayState *state = opaque;
>      fseek(replay_file, state->file_offset, SEEK_SET);
> +    qemu_clock_set_last(QEMU_CLOCK_HOST, state->host_clock_last);
>      /* If this was a vmstate, saved in recording mode,
>         we need to initialize replay data fields. */
>      replay_fetch_data_kind();
> @@ -54,6 +56,7 @@ static const VMStateDescription vmstate_replay = {
>          VMSTATE_UINT32(has_unread_data, ReplayState),
>          VMSTATE_UINT64(file_offset, ReplayState),
>          VMSTATE_UINT64(block_request_id, ReplayState),
> +        VMSTATE_UINT64(host_clock_last, ReplayState),
>          VMSTATE_END_OF_LIST()
>      },
>  };
> diff --git a/util/qemu-timer.c b/util/qemu-timer.c
> index 82d5650..2ed1bf2 100644
> --- a/util/qemu-timer.c
> +++ b/util/qemu-timer.c
> @@ -622,6 +622,18 @@ int64_t qemu_clock_get_ns(QEMUClockType type)
>      }
>  }
>  
> +uint64_t qemu_clock_get_last(QEMUClockType type)
> +{
> +    QEMUClock *clock = qemu_clock_ptr(type);
> +    return clock->last;
> +}
> +
> +void qemu_clock_set_last(QEMUClockType type, uint64_t last)
> +{
> +    QEMUClock *clock = qemu_clock_ptr(type);
> +    clock->last = last;
> +}
> +
>  void qemu_clock_register_reset_notifier(QEMUClockType type,
>                                          Notifier *notifier)
>  {
> 

Acked-by: Paolo Bonzini <address@hidden>