Date:   Fri, 1 Jul 2022 14:44:50 -0700
From:   Nicolin Chen <nicolinc@...dia.com>
To:     <joro@...tes.org>, <will@...nel.org>, <marcan@...can.st>,
        <sven@...npeter.dev>, <robin.murphy@....com>,
        <robdclark@...il.com>, <baolu.lu@...ux.intel.com>,
        <orsonzhai@...il.com>, <baolin.wang7@...il.com>,
        <zhang.lyra@...il.com>, <jean-philippe@...aro.org>,
        <alex.williamson@...hat.com>, <jgg@...dia.com>,
        <kevin.tian@...el.com>
CC:     <suravee.suthikulpanit@....com>, <alyssa@...enzweig.io>,
        <dwmw2@...radead.org>, <mjrosato@...ux.ibm.com>,
        <gerald.schaefer@...ux.ibm.com>, <thierry.reding@...il.com>,
        <vdumpa@...dia.com>, <jonathanh@...dia.com>, <cohuck@...hat.com>,
        <thunder.leizhen@...wei.com>, <christophe.jaillet@...adoo.fr>,
        <chenxiang66@...ilicon.com>, <john.garry@...wei.com>,
        <yangyingliang@...wei.com>, <iommu@...ts.linux-foundation.org>,
        <iommu@...ts.linux.dev>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-s390@...r.kernel.org>,
        <linux-tegra@...r.kernel.org>,
        <virtualization@...ts.linux-foundation.org>, <kvm@...r.kernel.org>
Subject: [PATCH v5 0/5] cover-letter: Simplify vfio_iommu_type1 attach/detach routine

This is a preparatory series for IOMMUFD v2 patches. It enforces error
code -EMEDIUMTYPE in iommu_attach_device() and iommu_attach_group() when
an IOMMU domain and a device/group are incompatible. It also drops the
useless domain->ops check since it won't fail in current environment.

These allow VFIO iommu code to simplify its group attachment routine, by
avoiding the extra IOMMU domain allocations and attach/detach sequences
of the old code.

Worths mentioning the exact match for enforce_cache_coherency is removed
with this series, since there's very less value in doing that as KVM will
not be able to take advantage of it -- this just wastes domain memory.
Instead, we rely on Intel IOMMU driver taking care of that internally.

This is on github:
https://github.com/nicolinc/iommufd/commits/vfio_iommu_attach

Changelog
v5:
 * Rebased on top of Robin's "Simplify bus_type determination".
 * Fixed a wrong change returning -EMEDIUMTYPE in arm-smmu driver.
 * Added Baolu's "Reviewed-by".
v4:
 * Dropped -EMEDIUMTYPE change in mtk_v1 driver per Robin's input
 * Added Baolu's and Kevin's Reviewed-by lines
v3: https://lore.kernel.org/kvm/20220623200029.26007-1-nicolinc@nvidia.com/
 * Dropped all dev_err since -EMEDIUMTYPE clearly indicates what error.
 * Updated commit message of enforce_cache_coherency removing patch.
 * Updated commit message of domain->ops removing patch.
 * Replaced "goto out_unlock" with simply mutex_unlock() and return.
 * Added a line of comments for -EMEDIUMTYPE return check.
 * Moved iommu_get_msi_cookie() into alloc_attach_domain() as a cookie
   should be logically tied to the lifetime of a domain itself.
 * Added Kevin's "Reviewed-by".
v2: https://lore.kernel.org/kvm/20220616000304.23890-1-nicolinc@nvidia.com/
 * Added -EMEDIUMTYPE to more IOMMU drivers that fit the category.
 * Changed dev_err to dev_dbg for -EMEDIUMTYPE to avoid kernel log spam.
 * Dropped iommu_ops patch, and removed domain->ops in VFIO directly,
   since there's no mixed-driver use case that would fail the sanity.
 * Updated commit log of the patch removing enforce_cache_coherency.
 * Fixed a misplace of "num_non_pinned_groups--" in detach_group patch.
 * Moved "num_non_pinned_groups++" in PATCH-5 to the common path between
   domain-reusing and new-domain pathways, like the code previously did.
 * Fixed a typo in EMEDIUMTYPE patch.
v1: https://lore.kernel.org/kvm/20220606061927.26049-1-nicolinc@nvidia.com/

Jason Gunthorpe (1):
  vfio/iommu_type1: Prefer to reuse domains vs match enforced cache
    coherency

Nicolin Chen (4):
  iommu: Return -EMEDIUMTYPE for incompatible domain and device/group
  vfio/iommu_type1: Remove the domain->ops comparison
  vfio/iommu_type1: Clean up update_dirty_scope in detach_group()
  vfio/iommu_type1: Simplify group attachment

 drivers/iommu/amd/iommu.c                   |   2 +-
 drivers/iommu/apple-dart.c                  |   4 +-
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c |  15 +-
 drivers/iommu/arm/arm-smmu/arm-smmu.c       |   5 +-
 drivers/iommu/arm/arm-smmu/qcom_iommu.c     |   9 +-
 drivers/iommu/intel/iommu.c                 |  10 +-
 drivers/iommu/iommu.c                       |  28 ++
 drivers/iommu/ipmmu-vmsa.c                  |   4 +-
 drivers/iommu/omap-iommu.c                  |   3 +-
 drivers/iommu/s390-iommu.c                  |   2 +-
 drivers/iommu/sprd-iommu.c                  |   6 +-
 drivers/iommu/tegra-gart.c                  |   2 +-
 drivers/iommu/virtio-iommu.c                |   3 +-
 drivers/vfio/vfio_iommu_type1.c             | 352 ++++++++++----------
 14 files changed, 229 insertions(+), 216 deletions(-)

-- 
2.17.1

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