Re: [PATCH v1 1/3] dmadev: add inter-domain operations

[Jerin Jacob <jerinjacobk@gmail.com>]

On Sun, Oct 8, 2023 at 8:03 AM fengchengwen <fengchengwen@huawei.com> wrote:
>
> Hi Anatoly,
>
> On 2023/8/12 0:14, Anatoly Burakov wrote:
> > Add a flag to indicate that a specific device supports inter-domain
> > operations, and add an API for inter-domain copy and fill.
> >
> > Inter-domain operation is an operation that is very similar to regular
> > DMA operation, except either source or destination addresses can be in a
> > different process's address space, indicated by source and destination
> > handle values. These values are currently meant to be provided by
> > private drivers' API's.
> >
> > This commit also adds a controller ID field into the DMA device API.
> > This is an arbitrary value that may not be implemented by hardware, but
> > it is meant to represent some kind of device hierarchy.
> >
> > Signed-off-by: Vladimir Medvedkin <vladimir.medvedkin@intel.com>
> > Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
> > ---
>
> ...
>
> > +__rte_experimental
> > +static inline int
> > +rte_dma_copy_inter_dom(int16_t dev_id, uint16_t vchan, rte_iova_t src,
> > +             rte_iova_t dst, uint32_t length, uint16_t src_handle,
> > +             uint16_t dst_handle, uint64_t flags)
>
> I would suggest add more general extension:
> rte_dma_copy*(int16_t dev_id, uint16_t vchan, rte_iova_t src, rte_iova_t dst,
>               uint32_t length, uint64_t flags, void *param)
> The param only valid under some flags bits.
> As for this inter-domain extension: we could define inter-domain param struct.
>
>
> Whether add in current rte_dma_copy() API or add one new API, I think it mainly
> depend on performance impact of parameter transfer. Suggest more discuss for
> differnt platform and call specification.

Or move src_handle/dst_hanel to vchan config to enable better performance.
Application create N number of vchan based on the requirements.

>
>
> And last, Could you introduce the application scenarios of this feature?

Looks like VM to VM or container to container copy.

>
>
> Thanks.
>