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From: Jason Gunthorpe <jgg@nvidia.com>
To: Nicolin Chen <nicolinc@nvidia.com>
Cc: joro@8bytes.org, kevin.tian@intel.com,
	suravee.suthikulpanit@amd.com, will@kernel.org,
	robin.murphy@arm.com, sven@kernel.org, j@jannau.net,
	jean-philippe@linaro.org, robin.clark@oss.qualcomm.com,
	dwmw2@infradead.org, baolu.lu@linux.intel.com,
	yong.wu@mediatek.com, matthias.bgg@gmail.com,
	angelogioacchino.delregno@collabora.com, tjeznach@rivosinc.com,
	pjw@kernel.org, palmer@dabbelt.com, aou@eecs.berkeley.edu,
	heiko@sntech.de, schnelle@linux.ibm.com, mjrosato@linux.ibm.com,
	wens@csie.org, jernej.skrabec@gmail.com, samuel@sholland.org,
	thierry.reding@gmail.com, jonathanh@nvidia.com,
	iommu@lists.linux.dev, linux-kernel@vger.kernel.org,
	asahi@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
	linux-arm-msm@vger.kernel.org,
	linux-mediatek@lists.infradead.org,
	linux-riscv@lists.infradead.org,
	linux-rockchip@lists.infradead.org, linux-s390@vger.kernel.org,
	linux-sunxi@lists.linux.dev, linux-tegra@vger.kernel.org,
	virtualization@lists.linux.dev, patches@lists.linux.dev
Subject: Re: [PATCH v1 00/20] iommu: Introduce and roll out test_dev domain op
Date: Mon, 20 Oct 2025 13:24:13 -0300	[thread overview]
Message-ID: <20251020162413.GV316284@nvidia.com> (raw)
In-Reply-To: <cover.1760312725.git.nicolinc@nvidia.com>

On Sun, Oct 12, 2025 at 05:04:57PM -0700, Nicolin Chen wrote:
> Add a new test_dev domain op for drivers to run a compatibility test prior
> to the actual attachment at the driver level. Any incompatible attachment
> will be rejected early, allowing the iommu core to postpone any concurrent
> attachment during a device reset state.

I had to go back and find the original email from kevin to understand
this..

 
This is a preparatory series for new iommu_dev_reset APIs:
https://lore.kernel.org/all/cover.1756682135.git.nicolinc@nvidia.com/

That series parks the domain attachment at BLOCKED during a device
reset. To keep the uAPI this also required that any change in domain
during this reset sequence is just recorded and kept in the background
until the reset is finished.

This creates a weird hole where userspace could propose to attach to a
domain that is incompatible with the device during FLR, have that
attach queued and then ultimately have the domain attach fail when the
FLR concludes.

This can be mitigated by splitting out the compatability test from the
attach and having the core code check the compatability before
accepting a queued domain attach.

It was felt that the subtle uAPI change warrants this rework.

Jason

      parent reply	other threads:[~2025-10-20 16:24 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-13  0:04 [PATCH v1 00/20] iommu: Introduce and roll out test_dev domain op Nicolin Chen
2025-10-13  0:04 ` [PATCH v1 01/20] iommu: Lock group->mutex in iommu_deferred_attach() Nicolin Chen
2025-10-13  0:04 ` [PATCH v1 02/20] iommu: Introduce a test_dev domain op and an internal helper Nicolin Chen
2025-10-13  9:53   ` Niklas Schnelle
2025-10-13 17:22     ` Nicolin Chen
2025-10-14 14:20       ` Niklas Schnelle
2025-10-20 16:27   ` Jason Gunthorpe
2025-10-20 18:51     ` Nicolin Chen
2025-10-27 23:23       ` Jason Gunthorpe
2025-10-28  4:37         ` Nicolin Chen
2025-10-27 23:18   ` Nicolin Chen
2025-10-30  8:47   ` Tian, Kevin
2025-10-30 19:43     ` Nicolin Chen
2025-11-03 18:54       ` Jason Gunthorpe
2025-11-05  6:57         ` Tian, Kevin
2025-11-05 18:18           ` Nicolin Chen
2025-11-07 18:54             ` Jason Gunthorpe
2025-11-07 18:58               ` Nicolin Chen
2025-10-13  0:05 ` [PATCH v1 03/20] iommu/arm-smmu-v3: Implement arm_smmu_domain_test_dev Nicolin Chen
2025-10-20 16:32   ` Jason Gunthorpe
2025-10-20 20:08     ` Nicolin Chen
2025-10-27 23:26       ` Jason Gunthorpe
2025-10-28  6:54         ` Nicolin Chen
2025-10-13  0:05 ` [PATCH v1 04/20] iommu/intel: Implement test_dev callbacks to domain ops Nicolin Chen
2025-10-13  0:05 ` [PATCH v1 05/20] iommu/amd: " Nicolin Chen
2025-10-13  0:05 ` [PATCH v1 06/20] iommu/arm-smmu: Implement arm_smmu_test_dev Nicolin Chen
2025-10-13  0:05 ` [PATCH v1 07/20] iommu/qcom_iommu: Implement test_dev callbacks to domain ops Nicolin Chen
2025-10-13  0:05 ` [PATCH v1 08/20] iommu/riscv: Implement riscv_iommu_test_paging_domain Nicolin Chen
2025-10-13  0:05 ` [PATCH v1 09/20] iommu/mkt_iommu: Implement mtk_iommu_test_device Nicolin Chen
2025-10-13  0:05 ` [PATCH v1 10/20] iommu/apple-dart: Implement test_dev callbacks to domain ops Nicolin Chen
2025-10-13  0:05 ` [PATCH v1 11/20] iommu/ipmmu-vmsa: Implement ipmmu_domain_test_device Nicolin Chen
2025-10-13  0:05 ` [PATCH v1 12/20] iommu/sun50i-iommu: Implement sun50i_iommu_domain_test_device Nicolin Chen
2025-10-13  0:05 ` [PATCH v1 13/20] iommu/rockchip-iommu: Implement rk_iommu_identity_test_dev Nicolin Chen
2025-10-13  0:05 ` [PATCH v1 14/20] iommu/msm_iommu: Implement msm_iommu_domain_test_dev Nicolin Chen
2025-10-13  0:05 ` [PATCH v1 15/20] iommu/fsl_pamu_domain: Implement fsl_pamu_domain_test_device Nicolin Chen
2025-10-15 22:02   ` Nicolin Chen
2025-10-13  0:05 ` [PATCH v1 16/20] iommu/omap-iommu: Implement omap_iommu_domain_test_dev Nicolin Chen
2025-10-13  0:05 ` [PATCH v1 17/20] iommu/s390-iommu: Implement s390_iommu_domain_test_device Nicolin Chen
2025-10-13  9:59   ` Niklas Schnelle
2025-10-13  0:05 ` [PATCH v1 18/20] iommufd/selftest: Implement mock_domain_nop_test Nicolin Chen
2025-10-13  0:05 ` [PATCH v1 19/20] iommu/virtio-iommu: Implement viommu_domain_test_dev Nicolin Chen
2025-10-13  0:05 ` [PATCH v1 20/20] iommu/tegra-smmu: Implement tegra_smmu_domain_test_dev Nicolin Chen
2025-10-20 16:24 ` Jason Gunthorpe [this message]

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