Messages in this thread |  | | Subject | Re: [PATCH 5/5] vdpasim: vDPA device simulator | From | Jason Wang <> | Date | Wed, 5 Feb 2020 11:14:04 +0800 |
| |
On 2020/2/4 下午8:52, Jason Gunthorpe wrote: > On Tue, Feb 04, 2020 at 04:28:27PM +0800, Jason Wang wrote: >> On 2020/2/4 下午4:21, Zhu Lingshan wrote: >>>> +static const struct dma_map_ops vdpasim_dma_ops = { >>>> + .map_page = vdpasim_map_page, >>>> + .unmap_page = vdpasim_unmap_page, >>>> + .alloc = vdpasim_alloc_coherent, >>>> + .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. > IMHO you need to specify some 'dma_device', not try and play tricks > with dma_ops, or assuming the parent is always the device used for > dma. > > Jason
Right, this is what in my mind and discussed in the vhost-vdpa thread.
Will go this way.
Thanks
|  |