Re: [Qemu-devel] [PATCH 00/15] qdev: make reset semantics more clear and consistent, reset qbuses under virtio devices

[Paolo Bonzini <pbonzini@redhat.com>]

Il 18/12/2012 08:27, Paolo Bonzini ha scritto:
> Il 17/12/2012 22:43, Michael S. Tsirkin ha scritto:
>> On Mon, Dec 17, 2012 at 05:24:35PM +0100, Paolo Bonzini wrote:
>>> After discussion with mst on the topic of resetting virtio devices,
>>> here is a series that hopefully clarifies the semantics of bus and
>>> device resets.
>>>
>>> After this series, there are two kinds of resets:
>>
>> So just to clarify, what I proposed was this
>> (on top of my type safety patch). Then
>> all transports can call virtio_config_reset
>> when appropriate (e.g. when PA is set to 0).
>>
>> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
>>
>> diff --git a/hw/virtio.c b/hw/virtio.c
>> index f40a8c5..e65d7c8 100644
>> --- a/hw/virtio.c
>> +++ b/hw/virtio.c
>> @@ -554,6 +554,14 @@ void virtio_reset(void *opaque)
>>      }
>>  }
>>  
>> +/* Device-specific reset through virtio config space.
>> + * Reset virtio config and backend child devices if any.
>> + */
>> +void virtio_config_reset(VirtIODevice *vdev)
>> +{
>> +    qdev_reset_all(vdev->binding_opaque);
>> +}
> 
> Yes, I had understood.  As I said, this is the wrong direction.
> Resetting happens from vdev->binding_opaque, it can just do
> qdev_reset_all(myself).

... besides, this only works if the reset callback of
vdev->binding_opaque remembers to call virtio_reset (in the s390
bindings, it doesn't and this series fixes it).  So IMO it is not only
useless, it is also misleading.

Paolo