PCIe P2P access to GPU memory

[Daniel Vetter]

On Sat, Sep 29, 2018 at 9:27 AM Koenig, Christian
<Christian.Koenig at amd.com> wrote:
>
> This is work in progress.
>
> I published patches to enable DMA_buf P2P a few months ago, but now I'm waiting for the PCI subsystem to pick up core support for this.
>
> I can prepare you a branch based on current upstream kernel next week if you want to test this.

Thread hijack, since I just read the lwn article on p2p for storage folks:

https://lwn.net/Articles/767281/

Totally doesn't match what I remember of your dma-buf p2p work. Do we
need to rework, or is this some kind of higher-level interface on top
of the raw p2p pci stuff? Or do I misremember.

Thanks, Daniel

>
> Regards,
> Christian.
>
> Am 29.09.2018 09:01 schrieb Dirk Eibach <dirk.eibach at googlemail.com>:
> I want to access GPU VRAM via PCIe P2P access, like DirectGMA but with
> mainline drivers.
> I can acquire a dmabuf from the GPU and pass it to my PCIe
> framegrabber. But I don't see a way to get the PCIe bus address of the
> video memory which I need for the P2P transfer. Is there already any
> infrastructure in place for doing this? If not, what would be the
> right way to implement this? Add another callback to the dmabuf
> struct?
>
> Cheers
> Dirk
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch