[PATCH 0/4] iommu/vt-d: Fix-up device-domain relationship by refactoring to use iommu group default domain.

[James Sewart]

Hey,

This patchset moves IOMMU_DOMAIN_DMA iommu domain management to iommu.c. 
This avoids the use of find_or_alloc_domain whose domain assignment is 
inconsistent with the iommu grouping as determined by pci_device_group.

Patch 3 permits domain type IOMMU_DOMAIN_DMA to be allocated via the 
iommu_ops api, allowing the default_domain of an iommu group to be set in 
iommu.c. This domain will be attached to every device that is brought up 
with an iommu group, and the devices reserved regions will be mapped using 
regions returned by get_resv_regions.

In intel_iommu_domain_alloc we donât know the IOMMU this domain will be 
associated with so we defer full initialisation until 
intel_iommu_attach_device. Currently iommu.c:iommu_group_add_device will 
try to map a devices reserved regions before attaching the domain which 
would cause issue if the domain is not fully initialised. This is 
addressed in patch 1 by moving the mapping to after attaching.

Patch 2 implements function apply_resv_region, used in 
iommu_group_create_direct_mappings to mark the reserved regions as non 
mappable for the dma_map_ops api.

Patch 4 removes the domain lazy allocation logic. Before this patch the 
lazy allocation logic would not be used as any domain allocated using 
these paths would be replaced when attaching the group default domain. 
Default domain allocation has been tested with and without this patch on 
4.19.

Cheers,
James.

James Sewart (4):
  iommu: Move iommu_group_create_direct_mappings to after device_attach
  iommu/vt-d: Implement apply_resv_region for reserving IOVA ranges
  iommu/vt-d: Allow IOMMU_DOMAIN_DMA and IOMMU_DOMAIN_IDENTITY to be allocated
  iommu/vt-d: Remove lazy allocation of domains

 drivers/iommu/intel-iommu.c | 329 ++++++++++++------------------------
 drivers/iommu/iommu.c       |   4 +-
 2 files changed, 108 insertions(+), 225 deletions(-)

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2.17.1