On Mon, 2026-09-21 at 08:43 +0200, Christian König wrote:
> On 9/18/26 19:05, Jason Gunthorpe wrote:
> > On Fri, Sep 18, 2026 at 03:42:28PM +0200, Thomas Hellström wrote:
> > > 
> > > 1) Xe attachment check if pci_p2pdma_distance() returns OK for
> > > the
> > > path. Then Xe always sets up dma-addresses using
> > > dma_map_resource(). 
> > 
> > Open coding pci_p2pdma_distance() in drivers is a hack. Using
> > dma_map_resource() like this was never "allowed".
> > 
> > We've fixed things so these hacks are not needed, the drivers need
> > to
> > move over to things like dma_buf_phys_vec_to_sgt() and the hmm
> > helpers
> > to use the DMA API correctly.
> 
> That is a completely broken approach as well since it limits the
> exported resources to addresses the CPU can reach.

And this would be OK for pcie_p2p, but not for other fast
interconnects, right? Or is this problematic also for pcie_p2p?

Thanks,
Thomas

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