From: "Christian König" <christian.koenig@amd.com>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Zhiping Zhang <zhipingz@meta.com>,
Alex Williamson <alex@shazbot.org>,
Leon Romanovsky <leon@kernel.org>,
Sumit Semwal <sumit.semwal@linaro.org>,
Bjorn Helgaas <helgaas@kernel.org>,
kvm@vger.kernel.org, linux-rdma@vger.kernel.org,
linux-pci@vger.kernel.org, netdev@vger.kernel.org,
dri-devel@lists.freedesktop.org, Keith Busch <kbusch@kernel.org>,
Yochai Cohen <yochai@nvidia.com>,
Yishai Hadas <yishaih@nvidia.com>
Subject: Re: [PATCH v5 0/4] vfio/dma-buf: add TPH support for peer-to-peer access
Date: Wed, 27 May 2026 14:53:04 +0200 [thread overview]
Message-ID: <a5ff1930-e9fb-43f5-82ab-9875d7a28421@amd.com> (raw)
In-Reply-To: <20260527123634.GK2487554@ziepe.ca>
On 5/27/26 14:36, Jason Gunthorpe wrote:
> On Wed, May 27, 2026 at 02:23:46PM +0200, Christian König wrote:
>
>> Yeah that's a good point, I should probably rephrase the question.
>>
>> I'm aware of how TPH works by adding the extra ST to the TLP.
>>
>> But my question is how is that useful to a PCIe endpoint? What is the effect of the ST here?
>
> TBH I've never heard Meta explain what their device is doing with
> it. At least it seems to be super important to their device..
Yeah I think at least a brief description of what is going on here would be necessary for the review.
Otherwise we have only the info that the exporter wants to give an opaque ST for the importer to use and no technical description what that is good for, how to test it etc...
Regards,
Christian.
>
> Jason
next prev parent reply other threads:[~2026-05-27 12:53 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20260526144401.1485788-1-zhipingz@meta.com>
2026-05-27 6:55 ` [PATCH v5 0/4] vfio/dma-buf: add TPH support for peer-to-peer access Christian König
2026-05-27 12:14 ` Jason Gunthorpe
2026-05-27 12:23 ` Christian König
2026-05-27 12:36 ` Jason Gunthorpe
2026-05-27 12:53 ` Christian König [this message]
[not found] ` <20260526144401.1485788-3-zhipingz@meta.com>
2026-05-27 6:57 ` [PATCH v5 2/4] dma-buf: add optional get_tph() callback Christian König
2026-05-27 17:03 ` Alex Williamson
[not found] ` <20260526144401.1485788-4-zhipingz@meta.com>
2026-05-27 18:06 ` [PATCH v5 3/4] vfio/pci: implement get_tph and DMA_BUF_TPH feature Alex Williamson
[not found] ` <20260526144401.1485788-5-zhipingz@meta.com>
2026-05-27 19:00 ` [PATCH v5 4/4] RDMA/mlx5: get tph for p2p access when registering dma-buf mr Alex Williamson
[not found] ` <20260526144401.1485788-2-zhipingz@meta.com>
2026-05-27 20:53 ` [PATCH v5 1/4] PCI/TPH: expose the enabled TPH requester type Alex Williamson
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