From: Jason Gunthorpe <jgg@ziepe.ca>
To: fengchengwen <fengchengwen@huawei.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, dri-devel@lists.freedesktop.org,
Keith Busch <kbusch@kernel.org>, Yochai Cohen <yochai@nvidia.com>,
Yishai Hadas <yishaih@nvidia.com>,
Zhiping Zhang <zhipingz@meta.com>
Subject: Re: [RFC] Proposal: Add sysfs interface for PCIe TPH Steering Tag retrieval and configuration
Date: Tue, 14 Apr 2026 12:11:25 -0300 [thread overview]
Message-ID: <20260414151125.GF2577880@ziepe.ca> (raw)
In-Reply-To: <11eaea26-ec10-264a-db1e-951f6b46078d@huawei.com>
On Tue, Apr 14, 2026 at 10:46:00PM +0800, fengchengwen wrote:
> We have a real platform requirement:
>
> * 1. Devices in TPH Device-Specific Mode with no standard ST table
> * 2. Steering Tags must be obtained from ACPI _DSM (kernel-only)
> * 3. Devices are fully managed by userspace drivers (VFIO/UIO)
> * 4. Userspace must program STs into vendor-specific registers
No, this is nonsenscial too.
If you want to control the steering tags for MMIO BAR memory exposed
by VFIO then the DMABUF mechanism Keith & co has been working on is
the correct approach.
If the VFIO user needs to control steering tags for the device it is
directly controling then it must do that through VFIO ioctls.
Nobody messes around with other devices under the covers of the
operating kernel driver. Stop proposing that.
Jason
next prev parent reply other threads:[~2026-04-14 15:11 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-10 14:30 [RFC] Proposal: Add sysfs interface for PCIe TPH Steering Tag retrieval and configuration fengchengwen
2026-04-13 10:01 ` Leon Romanovsky
2026-04-13 12:04 ` fengchengwen
2026-04-13 19:19 ` Leon Romanovsky
2026-04-14 1:07 ` fengchengwen
2026-04-14 8:57 ` Leon Romanovsky
2026-04-14 9:30 ` fengchengwen
2026-04-14 10:35 ` Leon Romanovsky
[not found] ` <11eaea26-ec10-264a-db1e-951f6b46078d@huawei.com>
2026-04-14 15:11 ` Jason Gunthorpe [this message]
2026-04-15 1:47 ` fengchengwen
2026-04-13 13:35 ` Jason Gunthorpe
2026-04-14 1:33 ` fengchengwen
2026-04-14 11:57 ` Jason Gunthorpe
[not found] ` <284350ea-e398-12da-c3e2-e156a1e6d127@huawei.com>
2026-04-14 15:08 ` Jason Gunthorpe
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