From: Jason Gunthorpe <jgg@ziepe.ca>
To: Zhiping Zhang <zhipingz@meta.com>
Cc: Leon Romanovsky <leon@kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>,
linux-rdma@vger.kernel.org, linux-pci@vger.kernel.org,
netdev@vger.kernel.org, Keith Busch <kbusch@kernel.org>,
Yochai Cohen <yochai@nvidia.com>,
Yishai Hadas <yishaih@nvidia.com>
Subject: Re: [RFC 2/2] Set steering-tag directly for PCIe P2P memory access
Date: Tue, 13 Jan 2026 12:49:23 -0400 [thread overview]
Message-ID: <20260113164923.GQ745888@ziepe.ca> (raw)
In-Reply-To: <20260113074318.941459-1-zhipingz@meta.com>
On Mon, Jan 12, 2026 at 11:43:13PM -0800, Zhiping Zhang wrote:
> Got it, thanks for pointing out the security concern! To address this, I
> propose that we still pass the TPH value when allocating the dmah, but we add
> a verification callback in the reg_mr_dmabuf flow to the dmabuf exporter. This
> callback will ensure that the TPH value is correctly linked to the exporting
> device’s MMIO, and only the exporter can authorize the TPH/tag association.
That still sounds messy because we have to protect CPU memory.
I think you should not use dmah possibly and make it so the dmabuf
entirely supplies the TPH value.
Jason
next prev parent reply other threads:[~2026-01-13 16:49 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-13 21:37 [RFC 0/2] Set steering-tag directly for PCIe P2P memory access Zhiping Zhang
2025-11-13 21:37 ` [RFC 1/2] " Zhiping Zhang
2025-11-14 13:12 ` Jonathan Cameron
2025-11-18 0:50 ` zhipingz
2025-11-24 21:27 ` Bjorn Helgaas
2025-12-01 17:43 ` Zhiping Zhang
2025-11-13 21:37 ` [RFC 2/2] " Zhiping Zhang
2025-11-17 16:00 ` Jason Gunthorpe
2025-11-20 7:24 ` Zhiping Zhang
2025-11-20 13:11 ` Jason Gunthorpe
2025-12-04 8:10 ` Zhiping Zhang
2025-12-27 19:22 ` Zhiping Zhang
2026-01-06 0:57 ` Jason Gunthorpe
2026-01-13 7:43 ` Zhiping Zhang
2026-01-13 16:49 ` Jason Gunthorpe [this message]
2026-01-24 1:13 ` Zhiping Zhang
2026-01-28 16:57 ` Jason Gunthorpe
2026-02-02 6:04 ` Zhiping Zhang
2026-01-03 5:38 ` [RFC 2/2] [fix] mlx5: modifications for use cases other than CPU Zhiping Zhang
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