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From: Yi Liu <yi.l.liu@intel.com>
To: joro@8bytes.org, jgg@nvidia.com, kevin.tian@intel.com,
	baolu.lu@linux.intel.com
Cc: alex.williamson@redhat.com, robin.murphy@arm.com,
	eric.auger@redhat.com, nicolinc@nvidia.com, kvm@vger.kernel.org,
	chao.p.peng@linux.intel.com, yi.l.liu@intel.com,
	iommu@lists.linux.dev, zhenzhong.duan@intel.com,
	jacob.jun.pan@intel.com
Subject: [PATCH v2 0/2] Two enhancements to iommu_at[de]tach_device_pasid()
Date: Thu, 28 Mar 2024 05:29:56 -0700	[thread overview]
Message-ID: <20240328122958.83332-1-yi.l.liu@intel.com> (raw)

There are minor mistakes in the iommu set_dev_pasid() and remove_dev_pasid()
paths. The set_dev_pasid() path updates the group->pasid_array first, and
then call into remove_dev_pasid() in error handling when there are devices
within the group that failed to set_dev_pasid. The remove_dev_pasid()
callbacks of the underlying iommu drivers get the domain for pasid from the
group->pasid_array. So the remove_dev_pasid() callback may get a wrong domain
in the set_dev_pasid() path. [1] Even if the group is singleton, the existing
code logic would have unnecessary warnings in the error handling of the
set_dev_pasid() path. e.g. intel iommu driver.

The above issue can be fixed by improving the error handling in the
set_dev_pasid() path. Also, this reminds that it is not reliable for the
underlying iommu driver callback to get the domain from group->pasid_array.
So, the second patch of this series passes the domain to remove_dev_pasid
op.

[1] https://lore.kernel.org/linux-iommu/20240320123803.GD159172@nvidia.com/

Change log:

v2:
 - Make clear that the patch 1/2 of v1 does not fix the problem (Kevin)
 - Swap the order of patch 1/2 and 2/2 of v1. In this new series, patch 1/2
   fixes the real issue, patch 2/2 is to avoid potential issue in the future.

v1: https://lore.kernel.org/linux-iommu/20240327125433.248946-1-yi.l.liu@intel.com/

Regards,
	Yi Liu

Yi Liu (2):
  iommu: Undo pasid attachment only for the devices that have succeeded
  iommu: Pass domain to remove_dev_pasid() op

 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c |  9 ++-----
 drivers/iommu/intel/iommu.c                 | 11 +++-----
 drivers/iommu/iommu.c                       | 28 ++++++++++++++-------
 include/linux/iommu.h                       |  3 ++-
 4 files changed, 26 insertions(+), 25 deletions(-)

-- 
2.34.1


             reply	other threads:[~2024-03-28 12:30 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-28 12:29 Yi Liu [this message]
2024-03-28 12:29 ` [PATCH v2 1/2] iommu: Undo pasid attachment only for the devices that have succeeded Yi Liu
2024-04-03  3:08   ` Baolu Lu
2024-03-28 12:29 ` [PATCH v2 2/2] iommu: Pass domain to remove_dev_pasid() op Yi Liu
2024-03-29  3:32   ` Tian, Kevin
2024-04-03  3:04   ` Baolu Lu
2024-04-03  3:25     ` Yi Liu
2024-04-05 18:17       ` Jason Gunthorpe
2024-03-29  2:12 ` [PATCH v2 0/2] Two enhancements to iommu_at[de]tach_device_pasid() Duan, Zhenzhong
2024-03-29  3:38   ` Yi Liu
2024-03-29  5:31     ` Duan, Zhenzhong
2024-04-03  2:56   ` Baolu Lu
2024-04-03  4:14     ` Duan, Zhenzhong
2024-04-12 10:13 ` Joerg Roedel

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