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From:   Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
To:     iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Cc:     joro@8bytes.org, gregkh@linuxfoundation.org,
        rafael.j.wysocki@intel.com,
        Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Subject: [PATCH 0/2] iommu/amd: Handle IOMMU initialization failure
Date:   Tue, 19 Jun 2018 11:45:32 -0500
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Currently, AMD system will not boot if the AMD IOMMU driver initialization
fails. This is mainly due to devices' dma_ops are still configured to use
amd_iommu_ops. Instead, the driver should retore the device dma_ops to
the default one as part of its error recovery.

However, other clean ups should also be taken care of (e.g. removing
IOMMU groups, and unsetting bus IOMMU).

NOTE: This issue was found when booting Linux with pci=nomsi option.
      Since the AMD IOMMU requires MSI, this result in failure to
      initialize IOMMU interrupt.

Thanks,
Suravee

Suravee Suthikulpanit (2):
  iommu: Introduce interface for unsetting bus IOMMU
  iommu/amd: Fallback to dma_direct_ops when fail to enable IOMMU

 drivers/iommu/amd_iommu.c       | 14 +++++++++++++-
 drivers/iommu/amd_iommu_init.c  | 19 +++++++++++++++++--
 drivers/iommu/amd_iommu_proto.h |  2 ++
 drivers/iommu/iommu.c           | 22 ++++++++++++++++++++++
 include/linux/device.h          |  1 +
 include/linux/iommu.h           |  1 +
 6 files changed, 56 insertions(+), 3 deletions(-)

-- 
2.7.4