linux-kernel - Re: [PATCH RFCv1 1/3] PCI: Allow ATS to be always on for CXL.cache capable devices

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20260122165827.GS1134360@nvidia.com>
Date: Thu, 22 Jan 2026 12:58:27 -0400
From: Jason Gunthorpe <jgg@...dia.com>
To: Nicolin Chen <nicolinc@...dia.com>
Cc: dan.j.williams@...el.com,
	Jonathan Cameron <jonathan.cameron@...wei.com>,
	"Tian, Kevin" <kevin.tian@...el.com>,
	"will@...nel.org" <will@...nel.org>,
	"robin.murphy@....com" <robin.murphy@....com>,
	"bhelgaas@...gle.com" <bhelgaas@...gle.com>,
	"joro@...tes.org" <joro@...tes.org>,
	"praan@...gle.com" <praan@...gle.com>,
	"baolu.lu@...ux.intel.com" <baolu.lu@...ux.intel.com>,
	"miko.lenczewski@....com" <miko.lenczewski@....com>,
	"linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>,
	"iommu@...ts.linux.dev" <iommu@...ts.linux.dev>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	linux-cxl@...r.kernel.org
Subject: Re: [PATCH RFCv1 1/3] PCI: Allow ATS to be always on for CXL.cache
 capable devices

On Thu, Jan 22, 2026 at 08:29:10AM -0800, Nicolin Chen wrote:
> On Thu, Jan 22, 2026 at 09:14:32AM -0400, Jason Gunthorpe wrote:
> > On Wed, Jan 21, 2026 at 09:44:32PM -0800, dan.j.williams@...el.com wrote:
> > > "We have a less than perfect legacy way (PCI untrusted flag) to nod at
> > >  ATS security problems. Let us ignore even that for a new class of
> > >  devices that advertise they can trigger all the old security problems
> > >  plus new ones."
> > 
> > Ah, I missed that we are already force disabling ATS in this untrusted
> > case, so we should ensure that continues to be the case here
> > too. Nicolin does it need a change?
> 
> pci_ats_always_on() validates against !pci_ats_supported(pdev), so
> we ensured that untrusted devices would not be always on.
> 
> Perhaps we should highlight in the commit message, as it's a topic?

Yes

Jason