Re: [RFC PATCH v2] uacce: Add uacce_ctrl misc device

[Jason Gunthorpe]

On Fri, Jan 29, 2021 at 10:09:03AM +0000, Tian, Kevin wrote:
> > SVA is not doom to work with IO page fault only. If we have SVA+pin,
> > we would get both sharing address and stable I/O latency.
> 
> Isn't it like a traditional MAP_DMA API (imply pinning) plus specifying 
> cpu_va of the memory pool as the iova? 

I think their issue is the HW can't do the cpu_va trick without also
involving the system IOMMU in a SVA mode

It really is something that belongs under some general /dev/sva as we
talked on the vfio thread

Jason