From: Jason Gunthorpe <jgg@nvidia.com>
To: Nicolin Chen <nicolinc@nvidia.com>
Cc: dan.j.williams@intel.com, "Tian, Kevin" <kevin.tian@intel.com>,
Jonathan Cameron <jonathan.cameron@huawei.com>,
"will@kernel.org" <will@kernel.org>,
"robin.murphy@arm.com" <robin.murphy@arm.com>,
"bhelgaas@google.com" <bhelgaas@google.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" <linux-cxl@vger.kernel.org>
Subject: Re: [PATCH RFCv1 1/3] PCI: Allow ATS to be always on for CXL.cache capable devices
Date: Thu, 19 Feb 2026 13:41:39 -0400 [thread overview]
Message-ID: <20260219174139.GI723117@nvidia.com> (raw)
In-Reply-To: <aZc//6kvH3Eqfwfe@nvidia.com>
On Thu, Feb 19, 2026 at 08:53:19AM -0800, Nicolin Chen wrote:
> The thing is that those driver_managed_dma callbacks don't call
> iommu_device_use_default_domain(). So, the iommu core loses the
> trigger to switch domain from BLOCKED/empty-DMA to DMA/IDENTITY.
But they don't use DMA API at all so it doesn't matter to them.
Your issue is that BLOCKED breaks MSI on ARM. That is fixed by using
an empty-DMA API domain as default.
What is missing is to bring back the IDENTITY performance optimization
in a secure way.
Jason
next prev parent reply other threads:[~2026-02-19 17:42 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
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 [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260219174139.GI723117@nvidia.com \
--to=jgg@nvidia.com \
--cc=baolu.lu@linux.intel.com \
--cc=bhelgaas@google.com \
--cc=dan.j.williams@intel.com \
--cc=iommu@lists.linux.dev \
--cc=jonathan.cameron@huawei.com \
--cc=joro@8bytes.org \
--cc=kevin.tian@intel.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-cxl@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=miko.lenczewski@arm.com \
--cc=nicolinc@nvidia.com \
--cc=praan@google.com \
--cc=robin.murphy@arm.com \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.