Re: [PATCH v4 2/3] mac_via: fix incorrect creation of mos6522 device in mac_via

[Mark Cave-Ayland]

On 09/03/2020 14:14, Markus Armbruster wrote:

> Pan Nengyuan <address@hidden> writes:
> 
>> On 3/9/2020 8:34 PM, Markus Armbruster wrote:
>>> Peter Maydell <address@hidden> writes:
>>>
>>>> On Mon, 9 Mar 2020 at 10:02, Pan Nengyuan <address@hidden> wrote:
>>>>> On 3/9/2020 5:21 PM, Peter Maydell wrote:
>>>>>> Could you explain more? My thought is that we should be using
>>>>>> sysbus_init_child_obj() and we should be doing it in the init method.
>>>>>> Why does that break the tests ? It's the same thing various other
>>>>>> devices do.
>>>>>
>>>>> device-introspect-test do the follow check for each device type:
>>>>>
>>>>>     qtree_start = qtest_hmp(qts, "info qtree");
>>>>>     ...
>>>>>     qtest_qmp(qts, "{'execute': 'device-list-properties','arguments': 
>>>>> {'typename': %s}}", type);
>>>>>     ...
>>>>>     qtree_end = qtest_hmp(qts, "info qtree");
>>>>>     g_assert_cmpstr(qtree_start, ==, qtree_end);
>>>>>
>>>>> If we do qdev_set_parent_bus in init, it will check fail when type = 
>>>>> 'mac_via'.
>>>>> mac_via_init() is called by q800_init(). But it will not be called in 
>>>>> qtest(-machine none) in the step qtree_start.
>>>>> And after we call 'device-list-properties', mac_via_init() was called and 
>>>>> set dev parent bus. We can find these
>>>>> devices in the qtree_end. So it break the test on the assert.
>>>>
>>>> Markus, do you know what's happening here? Why is
>>>> trying to use sysbus_init_child_obj() breaking the
>>>> device-introspect-test for this particular device,
>>>> but fine for the other places where we use it?
>>>> (Maybe we're accidentally leaking a reference to
>>>> something so the sub-device stays on the sysbus
>>>> when it should have removed itself when the
>>>> device was deinited ?)
>>>
>>> Pan Nengyuan, please provide the exact patch that fails for you.
>>
>> As the follow patch:
>>
>> >From 9b4f35e294597410cc03b967c127242ce099692e Mon Sep 17 00:00:00 2001
>> From: Pan Nengyuan <address@hidden>
>> Date: Wed, 4 Mar 2020 11:29:28 +0800
>> Subject: [PATCH] mac_via: fix incorrect creation of mos6522 device in mac_via
>>
>> This patch fix a bug in mac_via where it failed to actually realize devices 
>> it was using.
>> And move the init codes which inits the mos6522 objects and properties on 
>> them from realize()
>> into init(). However, we keep qdev_set_parent_bus in realize(), otherwise it 
>> will cause
>> device-introspect-test test fail. Then do the realize mos6522 device in the 
>> mac_vir_realize.
>>
>> Signed-off-by: Pan Nengyuan <address@hidden>
>> ---
>>  hw/misc/mac_via.c | 40 ++++++++++++++++++++++++++--------------
>>  1 file changed, 26 insertions(+), 14 deletions(-)
>>
>> diff --git a/hw/misc/mac_via.c b/hw/misc/mac_via.c
>> index b7d0012794..4c5c432140 100644
>> --- a/hw/misc/mac_via.c
>> +++ b/hw/misc/mac_via.c
>> @@ -868,24 +868,21 @@ static void mac_via_reset(DeviceState *dev)
>>  static void mac_via_realize(DeviceState *dev, Error **errp)
>>  {
>>      MacVIAState *m = MAC_VIA(dev);
>> -    MOS6522State *ms;
>>      struct tm tm;
>>      int ret;
>> +    Error *err = NULL;
>>
>> -    /* Init VIAs 1 and 2 */
>> -    sysbus_init_child_obj(OBJECT(dev), "via1", &m->mos6522_via1,
>> -                          sizeof(m->mos6522_via1), TYPE_MOS6522_Q800_VIA1);
>> -
>> -    sysbus_init_child_obj(OBJECT(dev), "via2", &m->mos6522_via2,
>> -                          sizeof(m->mos6522_via2), TYPE_MOS6522_Q800_VIA2);
>> +    object_property_set_bool(OBJECT(&m->mos6522_via1), true, "realized", 
>> &err);
>> +    if (err != NULL) {
>> +        error_propagate(errp, err);
>> +        return;
>> +    }
>>
>> -    /* Pass through mos6522 output IRQs */
>> -    ms = MOS6522(&m->mos6522_via1);
>> -    object_property_add_alias(OBJECT(dev), "irq[0]", OBJECT(ms),
>> -                              SYSBUS_DEVICE_GPIO_IRQ "[0]", &error_abort);
>> -    ms = MOS6522(&m->mos6522_via2);
>> -    object_property_add_alias(OBJECT(dev), "irq[1]", OBJECT(ms),
>> -                              SYSBUS_DEVICE_GPIO_IRQ "[0]", &error_abort);
>> +    object_property_set_bool(OBJECT(&m->mos6522_via2), true, "realized", 
>> &err);
>> +    if (err != NULL) {
>> +        error_propagate(errp, err);
>> +        return;
>> +    }
>>
>>      /* Pass through mos6522 input IRQs */
>>      qdev_pass_gpios(DEVICE(&m->mos6522_via1), dev, "via1-irq");
>> @@ -932,6 +929,7 @@ static void mac_via_init(Object *obj)
>>  {
>>      SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
>>      MacVIAState *m = MAC_VIA(obj);
>> +    MOS6522State *ms;
>>
>>      /* MMIO */
>>      memory_region_init(&m->mmio, obj, "mac-via", 2 * VIA_SIZE);
>> @@ -948,6 +946,20 @@ static void mac_via_init(Object *obj)
>>      /* ADB */
>>      qbus_create_inplace((BusState *)&m->adb_bus, sizeof(m->adb_bus),
>>                          TYPE_ADB_BUS, DEVICE(obj), "adb.0");
>> +
>> +    /* Init VIAs 1 and 2 */
>> +    sysbus_init_child_obj(OBJECT(m), "via1", &m->mos6522_via1,
>> +                          sizeof(m->mos6522_via1), TYPE_MOS6522_Q800_VIA1);
>> +    sysbus_init_child_obj(OBJECT(dev), "via2", &m->mos6522_via2,
>> +                          sizeof(m->mos6522_via2), TYPE_MOS6522_Q800_VIA2);
>> +
>> +    /* Pass through mos6522 output IRQs */
>> +    ms = MOS6522(&m->mos6522_via1);
>> +    object_property_add_alias(OBJECT(m), "irq[0]", OBJECT(ms),
>> +                              SYSBUS_DEVICE_GPIO_IRQ "[0]", &error_abort);
>> +    ms = MOS6522(&m->mos6522_via2);
>> +    object_property_add_alias(OBJECT(m), "irq[1]", OBJECT(ms),
>> +                              SYSBUS_DEVICE_GPIO_IRQ "[0]", &error_abort);
>>  }
>>
>>  static void postload_update_cb(void *opaque, int running, RunState state)
>> --
>> 2.18.2
> 
> In file included from /work/armbru/qemu/include/hw/vmstate-if.h:12,
>                  from /work/armbru/qemu/include/migration/vmstate.h:30,
>                  from /work/armbru/qemu/hw/misc/mac_via.c:20:
> /work/armbru/qemu/hw/misc/mac_via.c: In function ‘mac_via_init’:
> /work/armbru/qemu/hw/misc/mac_via.c:953:34: error: ‘dev’ undeclared (first 
> use in this function); did you mean ‘div’?
>   953 |     sysbus_init_child_obj(OBJECT(dev), "via2", &m->mos6522_via2,
>       |                                  ^~~
> 
> Try again?

Looks like a simple copy/paste error: I think that line should read OBJECT(m) 
like
the one above it?


ATB,

Mark.