Re: [PATCH 06/21] vdpa: introduce virtqueue groups

[Jason Wang]

On 2021/1/4 下午6:04, Stefan Hajnoczi wrote:
> On Wed, Dec 16, 2020 at 02:48:03PM +0800, Jason Wang wrote:
> > This patch introduces virtqueue groups to vDPA device. The virtqueue
> > group is the minimal set of virtqueues that must share an address
> > space. And the adddress space identifier could only be attached to
> > a specific virtqueue group.
> >
> > A new mandated bus operation is introduced to get the virtqueue group
> > ID for a specific virtqueue.
> >
> > All the vDPA device drivers were converted to simply support a single
> > virtqueue group.
> >
> > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> > ---
> >   drivers/vdpa/ifcvf/ifcvf_main.c   |  9 ++++++++-
> >   drivers/vdpa/mlx5/net/mlx5_vnet.c |  8 +++++++-
> >   drivers/vdpa/vdpa.c               |  4 +++-
> >   drivers/vdpa/vdpa_sim/vdpa_sim.c  | 11 ++++++++++-
> >   include/linux/vdpa.h              | 12 +++++++++---
> >   5 files changed, 37 insertions(+), 7 deletions(-)
> Maybe consider calling it iotlb_group or iommu_group so the purpose of
> the group is clear?


I'm not sure. The reason that I choose virtqueue group is because:

1) Virtqueue is the only entity that tries to issues DMA
2) For IOMMU group, it may cause confusion to the existing IOMMU group 
who group devices
3) IOTLB is the concept in vhost, we don't have such definition in the 
virtio spec

Thanks