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

[Markus Armbruster <armbru@redhat.com>]

Pan Nengyuan <pannengyuan@huawei.com> writes:

> On 3/9/2020 8:34 PM, Markus Armbruster wrote:
>> Peter Maydell <peter.maydell@linaro.org> writes:
>> 
>>> On Mon, 9 Mar 2020 at 10:02, Pan Nengyuan <pannengyuan@huawei.com> 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 <pannengyuan@huawei.com>
> 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 <pannengyuan@huawei.com>
> ---
>  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?