Re: [RFC 0/4] Virtio uses DMA API for all devices

[Christoph Hellwig]

On Tue, Aug 07, 2018 at 02:45:25AM +0300, Michael S. Tsirkin wrote:
> > > I think that's where Christoph might have specific ideas about it.
> > 
> > OK well, assuming Christoph can solve the direct case in a way that
> > also work for the virtio !iommu case, we still want some bit of logic
> > somewhere that will "switch" to swiotlb based ops if the DMA mask is
> > limited.
> > 
> > You mentioned an RFC for that ? Do you happen to have a link ?
> 
> No but Christoph did I think.

Do you mean the direct map retpoline mitigation?  It is here:

https://www.spinics.net/lists/netdev/msg495413.html

https://www.spinics.net/lists/netdev/msg495785.html