linux-kernel - Re: [PATCH v7 5/5] PCI: Suspend iommu function prior to resetting a device

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] [day] [month] [year] [list]

Message-ID: <20251125192829.GG520526@nvidia.com>
Date: Tue, 25 Nov 2025 15:28:29 -0400
From: Jason Gunthorpe <jgg@...dia.com>
To: Nicolin Chen <nicolinc@...dia.com>
Cc: joro@...tes.org, afael@...nel.org, bhelgaas@...gle.com,
	alex@...zbot.org, will@...nel.org, robin.murphy@....com,
	lenb@...nel.org, kevin.tian@...el.com, baolu.lu@...ux.intel.com,
	linux-arm-kernel@...ts.infradead.org, iommu@...ts.linux.dev,
	linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
	linux-pci@...r.kernel.org, kvm@...r.kernel.org,
	patches@...ts.linux.dev, pjaroszynski@...dia.com, vsethi@...dia.com,
	helgaas@...nel.org, etzhao1900@...il.com
Subject: Re: [PATCH v7 5/5] PCI: Suspend iommu function prior to resetting a
 device

On Fri, Nov 21, 2025 at 05:57:32PM -0800, Nicolin Chen wrote:
> PCIe permits a device to ignore ATS invalidation TLPs while processing a
> reset. This creates a problem visible to the OS where an ATS invalidation
> command will time out: e.g. an SVA domain will have no coordination with a
> reset event and can racily issue ATS invalidations to a resetting device.
> 
> The PCIe r6.0, sec 10.3.1 IMPLEMENTATION NOTE recommends SW to disable and
> block ATS before initiating a Function Level Reset. It also mentions that
> other reset methods could have the same vulnerability as well.
> 
> The IOMMU subsystem provides pci_dev_reset_iommu_prepare/done() callback
> helpers for this matter. Use them in all the existing reset functions.
> 
> This will attach the device to its iommu_group->blocking_domain during the
> device reset, so as to allow IOMMU driver to:
>  - invoke pci_disable_ats() and pci_enable_ats(), if necessary
>  - wait for all ATS invalidations to complete
>  - stop issuing new ATS invalidations
>  - fence any incoming ATS queries
> 
> Reviewed-by: Kevin Tian <kevin.tian@...el.com>
> Signed-off-by: Nicolin Chen <nicolinc@...dia.com>
> ---
>  drivers/pci/pci-acpi.c | 13 +++++++--
>  drivers/pci/pci.c      | 65 +++++++++++++++++++++++++++++++++++++-----
>  drivers/pci/quirks.c   | 19 +++++++++++-
>  3 files changed, 87 insertions(+), 10 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@...dia.com>

Jason