Re: [RFC 1/4] memory: add memory_region_init_io_with_dev interface

[Li Qiang <liq3ea@gmail.com>]

Gerd Hoffmann <kraxel@redhat.com> 于2020年9月9日周三 下午12:49写道：
>
> On Wed, Sep 09, 2020 at 10:15:47AM +0800, Jason Wang wrote:
> >
> > On 2020/9/9 上午12:41, Li Qiang wrote:
> > > Currently the MR is not explicitly connecting with its device instead of
> > > a opaque. In most situation this opaque is the deivce but it is not an
> > > enforcement. This patch adds a DeviceState member of to MemoryRegion
> > > we will use it in later patch.
> >
> >
> > I don't have a deep investigation. But I wonder whether we could make sure
> > of owner instead of adding a new field here.
>
> Should be possible.  There is object_dynamic_cast() which can be used to
> figure whenever a given owner object is a device.
>

I found most caller of 'memory_region_init_io' will set the owner to
the device object.
But some of them will just set it to NULL. Do will have a clear rule
that the device's MR
'owner' should be the device object? If yes, we can use this field.

Thanks,
Li Qiang

> take care,
>   Gerd
>