Re: [Qemu-devel] [PATCH 05/10] RTC: Update the RTC clock only when reading it

[Juan Quintela <quintela@redhat.com>]

Paolo Bonzini <pbonzini@redhat.com> wrote:
> Il 02/08/2012 11:09, Juan Quintela ha scritto:
>> Why did you remove all the migration from previous versions?
>> You can't migrate now from version{1,2}, and we used to be able to do
>> it?
>> 
>> Why did you remove it?
>
> Because it won't work; we removed three fields.  You need to add
> rtc_load_old which is done later in the series.  But I guess I can use
> VMSTATE_UNUSED instead.

Something like (completely untested):

static bool version_less_3(void *opaque, int version_id)
{
    return version_id < 3;
}

static const VMStateDescription vmstate_rtc = {
    .name = "mc146818rtc",
    .version_id = 3,
    .minimum_version_id = 1,
    .minimum_version_id_old = 1,
    .post_load = rtc_post_load,
    .fields      = (VMStateField []) {
         VMSTATE_BUFFER(cmos_data, RTCState),
 @@ -542,11 +595,12 @@ static const VMStateDescription vmstate_rtc = {
         VMSTATE_INT32(current_tm.tm_year, RTCState),
         VMSTATE_TIMER(periodic_timer, RTCState),
         VMSTATE_INT64(next_periodic_time, RTCState),
         VMSTATE_UNUSED_TEST(8*3, v_less_3); //* whatever space */
-        VMSTATE_INT64(next_second_time, RTCState),
-        VMSTATE_TIMER(second_timer, RTCState),
-        VMSTATE_TIMER(second_timer2, RTCState),
         VMSTATE_UINT32_V(irq_coalesced, RTCState, 2),
         VMSTATE_UINT32_V(period, RTCState, 2),
+        VMSTATE_UINT64_V(base_rtc, RTCState, 3),
+        VMSTATE_UINT64_V(last_update, RTCState, 3),
+        VMSTATE_INT64_V(offset, RTCState, 3),
+        VMSTATE_TIMER_V(update_timer, RTCState, 3),
         VMSTATE_END_OF_LIST()
     }
 };


This will make "migration protocol" work,  I have zero clue if
"obviating" the value of next_second_time, and the two second_timers*
can work, that depends on how rtc works.  Perhaps some extra magic on
post_load() is needed, though.

Could you tell me if you need anything else?

Later, Juan.