Re: [PATCH v5 0/4] vfio/dma-buf: add TPH support for peer-to-peer access

[Jason Gunthorpe <jgg@ziepe.ca>]

On Fri, May 29, 2026 at 09:36:00AM +0200, Christian König wrote:
> On 5/29/26 08:34, Zhiping Zhang wrote:
> ...
> > There's no in-tree vendor PF driver
> 
> Well I have to admit it's a bit on the edge but this sentence is a
> show stopper.

I think he means the device is not SRIOV. vfio-pci is the in-kernel PF
driver.

> DMA-buf is an in kernel interface for buffer sharing between drivers
> and any change to it needs an in kernel driver as justification for
> the added complexity.

vfio is the in-kernel driver, this series fully shows the in-kernel
API using vfio as the exporter and mlx5 as the importer. It certainly
meets the standard required to show in-tree users.

> When you have a complete open source driver stack which utilizes
> VFIO passthrough as the interface to communicate with the kernel
> drivers then we can eventually talk about that.

That decision is not up to dmabuf - what VFIO subsystem requires to
accept a new UAPI is up to the VFIO maintainers.

DRM and VFIO have very different views on what is required to merge a
new uAPI.

Jason