Re: [virtio-dev] Memory sharing device

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Feb 21, 2019 at 10:59:02AM +0100, Gerd Hoffmann wrote:
>   Hi,
> 
> > > Note:  I think using a pci memory bar (aka host memory mapped into the
> > > guest) as backing storage for dma-bufs isn't going to work.
> > 
> > (Not knowing dma-bufs) but could you explain why?
> 
> Many places in the linux kernel assume dma-bufs are built out of normal
> ram pages (i.e. something backed by struct page).  Which is not the case
> for pci memory bars which are typically ioremapped() (completely or in
> chunks) to access them.
> 
> cheers,
>   Gerd

Can't we register PCI memory as ZONE_DEVICE?