Re: [PATCH v8 00/10] Introduce VDUSE - vDPA Device in Userspace

[Jason Wang]

在 2021/6/29 下午2:40, Yongji Xie 写道:
> On Tue, Jun 29, 2021 at 12:13 PM Jason Wang <jasowang@xxxxxxxxxx> wrote:
> > 在 2021/6/28 下午6:32, Yongji Xie 写道:
> > > > The large barrier is bounce-buffer mapping: SPDK requires hugepages
> > > > for NVMe over PCIe and RDMA, so take some preallcoated hugepages to
> > > > map as bounce buffer is necessary. Or it's hard to avoid an extra
> > > > memcpy from bounce-buffer to hugepage.
> > > > If you can add an option to map hugepages as bounce-buffer,
> > > > then SPDK could also be a potential user of vduse.
> > > I think we can support registering user space memory for bounce-buffer
> > > use like XDP does. But this needs to pin the pages, so I didn't
> > > consider it in this initial version.
> > Note that userspace should be unaware of the existence of the bounce buffer.
> If so, it might be hard to use umem. Because we can't use umem for
> coherent mapping which needs physical address contiguous space.
>
> Thanks,
> Yongji


We probably can use umem for memory other than the virtqueue (still via 
mmap()).

Thanks