Re: [RFC PATCH 10/24] vdpa: introduce config operations for associating ASID to a virtqueue group

[Jason Wang]

On 2020/10/1 下午9:29, Eli Cohen wrote:
> On Thu, Sep 24, 2020 at 11:21:11AM +0800, Jason Wang wrote:
> > This patch introduces a new bus operation to allow the vDPA bus driver
> > to associate an ASID to a virtqueue group.
> So in case of virtio_net, I would expect that all the data virtqueues
> will be associated with the same address space identifier.


Right.

I will add the codes to do this in the next version. It should be more 
explicit than have this assumption by default.


> Moreover,
> this assignment should be provided before the set_map call that provides
> the iotlb for the address space, correct?


I think it's better not have this limitation, note that set_map() now 
takes a asid argument.

So for hardware if the associated as is changed, the driver needs to 
program the hardware to switch to the new mapping.

Does this work for mlx5?


> > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> > ---
> >   include/linux/vdpa.h | 10 ++++++++++
> >   1 file changed, 10 insertions(+)
> >
> > diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> > index 1e1163daa352..e2394995a3cd 100644
> > --- a/include/linux/vdpa.h
> > +++ b/include/linux/vdpa.h
> > @@ -160,6 +160,12 @@ struct vdpa_device {
> >    * @get_generation:		Get device config generation (optional)
> >    *				@vdev: vdpa device
> >    *				Returns u32: device generation
> > + * @set_group_asid:		Set address space identifier for a
> > + *				virtqueue group
> > + *				@vdev: vdpa device
> > + *				@group: virtqueue group
> > + *				@asid: address space id for this group
> > + *				Returns integer: success (0) or error (< 0)
> >    * @set_map:			Set device memory mapping (optional)
> >    *				Needed for device that using device
> >    *				specific DMA translation (on-chip IOMMU)
> > @@ -237,6 +243,10 @@ struct vdpa_config_ops {
> >   		       u64 iova, u64 size, u64 pa, u32 perm);
> >   	int (*dma_unmap)(struct vdpa_device *vdev, unsigned int asid,
> >   			 u64 iova, u64 size);
> > +	int (*set_group_asid)(struct vdpa_device *vdev, unsigned int group,
> > +			      unsigned int asid);
> > +
> > +
> Extra space


Will fix.

Thanks


> >   
> >   	/* Free device resources */
> >   	void (*free)(struct vdpa_device *vdev);
> > --
> > 2.20.1