iommu/arm-smmu-v3: Do not change the STE twice during arm_smmu_attach_dev()

This was needed because the STE code required the STE to be in
ABORT/BYPASS inorder to program a cdtable or S2 STE. Now that the STE code
can automatically handle all transitions we can remove this step
from the attach_dev flow.

A few small bugs exist because of this:

1) If the core code does BLOCKED -> UNMANAGED with disable_bypass=false
   then there will be a moment where the STE points at BYPASS. Since
   this can be done by VFIO/IOMMUFD it is a small security race.

2) If the core code does IDENTITY -> DMA then any IOMMU_RESV_DIRECT
   regions will temporarily become BLOCKED. We'd like drivers to
   work in a way that allows IOMMU_RESV_DIRECT to be continuously
   functional during these transitions.

Make arm_smmu_release_device() put the STE back to the correct
ABORT/BYPASS setting. Fix a bug where a IOMMU_RESV_DIRECT was ignored on
this path.

As noted before the reordering of the linked list/STE/CD changes is OK
against concurrent arm_smmu_share_asid() because of the
arm_smmu_asid_lock.

Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Moritz Fischer <moritzf@google.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/7-v6-96275f25c39d+2d4-smmuv3_newapi_p1_jgg@nvidia.com
Signed-off-by: Will Deacon <will@kernel.org>

0 files changed, 0 insertions, 0 deletions