Re: [Qemu-devel] [PATCH] QMP: Introduce RTC_CHANGE event

[Anthony Liguori <anthony@codemonkey.ws>]

On 02/25/2010 09:11 AM, Luiz Capitulino wrote:
> Emitted whenever the RTC time changes.
>
> Signed-off-by: Luiz Capitulino<lcapitulino@redhat.com>
>    

Not that this change isn't acceptable, but I think we need to improve 
how we handle these events in the future.

> ---
>   QMP/qmp-events.txt |   15 +++++++++++++++
>   hw/mc146818rtc.c   |    2 ++
>   monitor.c          |    3 +++
>   monitor.h          |    1 +
>   sysemu.h           |    2 ++
>   vl.c               |    9 +++++++++
>   6 files changed, 32 insertions(+), 0 deletions(-)
>
> diff --git a/QMP/qmp-events.txt b/QMP/qmp-events.txt
> index b0183f9..f64b42d 100644
> --- a/QMP/qmp-events.txt
> +++ b/QMP/qmp-events.txt
> @@ -38,6 +38,21 @@ Example:
>   { "event": "RESET",
>       "timestamp": { "seconds": 1267041653, "microseconds": 9518 } }
>
> +RTC_CHANGE
> +----------
> +
> +Emitted when the RTC time changes.
> +
> +Data:
> +
> +- "offset": delta against the host UTC in seconds (json-number)
> +
> +Example:
> +
> +{ "event": "RTC_CHANGE",
> +    "data": { "offset": 78 },
> +    "timestamp": { "seconds": 1267020223, "microseconds": 435656 } }
> +
>   SHUTDOWN
>   --------
>
> diff --git a/hw/mc146818rtc.c b/hw/mc146818rtc.c
> index 2616d0d..a537855 100644
> --- a/hw/mc146818rtc.c
> +++ b/hw/mc146818rtc.c
> @@ -297,6 +297,8 @@ static void rtc_set_time(RTCState *s)
>       tm->tm_mday = rtc_from_bcd(s, s->cmos_data[RTC_DAY_OF_MONTH]);
>       tm->tm_mon = rtc_from_bcd(s, s->cmos_data[RTC_MONTH]) - 1;
>       tm->tm_year = rtc_from_bcd(s, s->cmos_data[RTC_YEAR]) + s->base_year - 1900;
> +
> +    rtc_change_mon_event(tm);
>   }
>
>   static void rtc_copy_date(RTCState *s)
> diff --git a/monitor.c b/monitor.c
> index b2f5842..20512da 100644
> --- a/monitor.c
> +++ b/monitor.c
> @@ -423,6 +423,9 @@ void monitor_protocol_event(MonitorEvent event, QObject *data)
>           case QEVENT_BLOCK_IO_ERROR:
>               event_name = "BLOCK_IO_ERROR";
>               break;
> +        case QEVENT_RTC_CHANGE:
> +            event_name = "RTC_CHANGE";
> +            break;
>           default:
>               abort();
>               break;
> diff --git a/monitor.h b/monitor.h
> index 8cc21f5..aa51bd5 100644
> --- a/monitor.h
> +++ b/monitor.h
> @@ -23,6 +23,7 @@ typedef enum MonitorEvent {
>       QEVENT_VNC_INITIALIZED,
>       QEVENT_VNC_DISCONNECTED,
>       QEVENT_BLOCK_IO_ERROR,
> +    QEVENT_RTC_CHANGE,
>       QEVENT_MAX,
>   } MonitorEvent;
>    

This is going against the direction that we're trying to take with 
qdev.  We're trying to modularize devices by having only the device 
themselves know their existence.  That's the beauty of things like -device.

The fact that we're putting knowledge of the RTC into monitor.[ch] and 
vl.c is a step in the wrong direction.  We really ought to be able to 
generate device specific events entirely within the device.

Regards,

Anthony Liguori

> diff --git a/sysemu.h b/sysemu.h
> index 8ba618e..b5587f4 100644
> --- a/sysemu.h
> +++ b/sysemu.h
> @@ -252,6 +252,8 @@ void do_usb_add(Monitor *mon, const QDict *qdict);
>   void do_usb_del(Monitor *mon, const QDict *qdict);
>   void usb_info(Monitor *mon);
>
> +void rtc_change_mon_event(struct tm *tm);
> +
>   void register_devices(void);
>
>   #endif
> diff --git a/vl.c b/vl.c
> index 3f580f5..6c05c93 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -1488,6 +1488,15 @@ int qemu_timedate_diff(struct tm *tm)
>       return seconds - time(NULL);
>   }
>
> +void rtc_change_mon_event(struct tm *tm)
> +{
> +    QObject *data;
> +
> +    data = qobject_from_jsonf("{ 'offset': %d }", qemu_timedate_diff(tm));
> +    monitor_protocol_event(QEVENT_RTC_CHANGE, data);
> +    qobject_decref(data);
> +}
> +
>   static void configure_rtc_date_offset(const char *startdate, int legacy)
>   {
>       time_t rtc_start_date;
>