Re: [PATCH 5/5] vdpasim: vDPA device simulator

[Jason Wang]

On 2020/2/4 äå4:21, Zhu Lingshan wrote:
> > +static const struct dma_map_ops vdpasim_dma_ops = {
> > +ÂÂÂ .map_page = vdpasim_map_page,
> > +ÂÂÂ .unmap_page = vdpasim_unmap_page,
> > +ÂÂÂ .alloc = vdpasim_alloc_coherent,
> > +ÂÂÂ .free = vdpasim_free_coherent,
> > +};
> > +
>
> Hey Jason,
>
> IMHO, it would be nice if dma_ops of the parent device could be 
> re-used. vdpa_device is expecting to represent a physical device 
> except this simulator, however, there are not enough information in 
> vdpa_device.dev to indicating which kind physical device it attached 
> to. Namely get_arch_dma_ops(struct bus type) can not work on 
> vdpa_device.dev. Then it seems device drivers need to implement a wrap 
> of dma_ops of parent devices. Can this work be done in the vdpa 
> framework since it looks like a common task? Can 
> "vd_dev->vdev.dev.parent = vdpa->dev->parent;" in virtio_vdpa_probe() 
> do the work?
>
> Thanks,
> BR
> Zhu Lingshan 


Good catch.

I think we can.

Thanks