From: Jason Gunthorpe <jgg@nvidia.com>
To: Jonathan Cameron <jonathan.cameron@huawei.com>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
Nicolin Chen <nicolinc@nvidia.com>,
"will@kernel.org" <will@kernel.org>,
"robin.murphy@arm.com" <robin.murphy@arm.com>,
"bhelgaas@google.com" <bhelgaas@google.com>,
"Williams, Dan J" <dan.j.williams@intel.com>,
"joro@8bytes.org" <joro@8bytes.org>,
"praan@google.com" <praan@google.com>,
"baolu.lu@linux.intel.com" <baolu.lu@linux.intel.com>,
"miko.lenczewski@arm.com" <miko.lenczewski@arm.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"iommu@lists.linux.dev" <iommu@lists.linux.dev>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
linux-cxl@vger.kernel.org
Subject: Re: [PATCH RFCv1 1/3] PCI: Allow ATS to be always on for CXL.cache capable devices
Date: Wed, 21 Jan 2026 09:03:15 -0400 [thread overview]
Message-ID: <20260121130315.GE1134360@nvidia.com> (raw)
In-Reply-To: <20260121100307.00004e60@huawei.com>
On Wed, Jan 21, 2026 at 10:03:07AM +0000, Jonathan Cameron wrote:
> On Wed, 21 Jan 2026 08:01:36 +0000
> "Tian, Kevin" <kevin.tian@intel.com> wrote:
>
> > +Dan. I recalled an offline discussion in which he raised concern on
> > having the kernel blindly enable ATS for cxl.cache device instead of
> > creating a knob for admin to configure from userspace (in case
> > security is viewed more important than functionality, upon allowing
> > DMA to read data out of CPU caches)...
> >
>
> +CC Linux-cxl
A cxl.cache device supporting ATS will automatically enable ATS today
if the kernel option to enable translation is set.
Even if the device is marked untrusted by the PCI layer (eg an
external port).
Yes this is effectively a security issue, but it is not really a CXL
specific problem.
We might perfer to not enable ATS for untrusted devices and then fail to
load drivers for "ats always on" cases.
Or maybe we can enable one of the ATS security features someday,
though I wonder if those work for CXL..
Jason
next prev parent reply other threads:[~2026-01-21 13:03 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-17 4:56 [PATCH RFCv1 0/3] Allow ATS to be always on for certain ATS-capable devices Nicolin Chen
2026-01-17 4:56 ` [PATCH RFCv1 1/3] PCI: Allow ATS to be always on for CXL.cache capable devices Nicolin Chen
2026-01-19 17:58 ` Jason Gunthorpe
2026-01-21 8:01 ` Tian, Kevin
2026-01-21 10:03 ` Jonathan Cameron
2026-01-21 13:03 ` Jason Gunthorpe [this message]
2026-01-22 1:17 ` Baolu Lu
2026-01-22 13:15 ` Jason Gunthorpe
2026-01-22 5:44 ` dan.j.williams
2026-01-22 13:14 ` Jason Gunthorpe
2026-01-22 16:29 ` Nicolin Chen
2026-01-22 16:58 ` Jason Gunthorpe
2026-01-22 19:46 ` dan.j.williams
2026-01-27 8:10 ` Tian, Kevin
2026-01-27 15:04 ` Jason Gunthorpe
2026-01-28 0:49 ` dan.j.williams
2026-01-28 13:05 ` Jason Gunthorpe
2026-02-03 5:13 ` Nicolin Chen
2026-02-03 14:33 ` Jason Gunthorpe
2026-02-03 17:45 ` Nicolin Chen
2026-02-03 17:55 ` Jason Gunthorpe
2026-02-03 18:50 ` Nicolin Chen
2026-02-04 13:21 ` Jason Gunthorpe
2026-02-03 18:59 ` Robin Murphy
2026-02-03 19:24 ` Nicolin Chen
2026-02-03 23:16 ` Jason Gunthorpe
2026-02-04 12:18 ` Robin Murphy
2026-02-04 13:20 ` Jason Gunthorpe
2026-02-18 22:56 ` Nicolin Chen
2026-02-19 14:37 ` Jason Gunthorpe
2026-02-19 16:53 ` Nicolin Chen
2026-02-19 17:41 ` Jason Gunthorpe
2026-02-20 4:52 ` Nicolin Chen
2026-02-20 12:50 ` Jason Gunthorpe
2026-02-20 13:22 ` Robin Murphy
2026-02-20 13:51 ` Jason Gunthorpe
2026-02-20 14:45 ` Robin Murphy
2026-02-26 15:10 ` Jason Gunthorpe
2026-02-20 18:49 ` Nicolin Chen
2026-02-24 14:38 ` Jason Gunthorpe
2026-01-28 0:57 ` Tian, Kevin
2026-01-28 13:11 ` Jason Gunthorpe
2026-01-29 3:28 ` Tian, Kevin
2026-01-22 10:24 ` Alejandro Lucero Palau
2026-01-17 4:56 ` [PATCH RFCv1 2/3] PCI: Allow ATS to be always on for non-CXL NVIDIA GPUs Nicolin Chen
2026-01-19 18:00 ` Jason Gunthorpe
2026-01-19 18:09 ` Nicolin Chen
2026-01-17 4:56 ` [PATCH RFCv1 3/3] iommu/arm-smmu-v3: Allow ATS to be always on Nicolin Chen
2026-01-19 20:06 ` Jason Gunthorpe
2026-01-26 12:39 ` Will Deacon
2026-01-26 17:20 ` Jason Gunthorpe
2026-01-26 18:40 ` Nicolin Chen
2026-01-26 19:16 ` Jason Gunthorpe
2026-01-26 18:49 ` Robin Murphy
2026-01-26 19:09 ` Jason Gunthorpe
2026-01-27 13:10 ` Will Deacon
2026-01-27 13:26 ` Robin Murphy
2026-01-27 13:50 ` Will Deacon
2026-01-27 14:49 ` Jason Gunthorpe
2026-01-26 18:21 ` Nicolin Chen
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