[PATCH 0/5] Share sva domains with all devices bound to a mm

Tina Zhang
2023-08-08T16:42:30Z

A sva domain's lifetime begins with binding a device to a mm and ends
by releasing all the bound devices from that sva domain. Technically,
there could be more than one sva domain identified by the mm PASID for
the use of bound devices issuing DMA transactions.

To support mm PASID 1:n with sva domains, each mm needs to keep both a
reference list of allocated sva domains and the corresponding PASID.
However, currently, mm struct only has one pasid field for sva usage,
which is used to keep the info of an assigned PASID. That pasid field
cannot provide sufficient info to build up the 1:n mapping between PASID
and sva domains.

This patch-set fills the gap by adding an mm_iommu field[1], whose type is
mm_iommu_data struct, to replace the old pasid field. The introduced
mm_iommu_data struct keeps info of both a reference list of sva domains
and an assigned PASID.

[1]: https://lore.kernel.org/linux-iommu/ZIBxPd1%2FJCAle6yP@nvidia.com/

The RFC version of this patch-set is here:
https://lore.kernel.org/linux-iommu/20230707013441.365583-1-tina.zhang@intel.com/

Tina Zhang (5):
iommu: Add mm_get_pasid() helper function
iommu: Call helper function to get assigned pasid value
mm: Add structure to keep sva information
iommu: Support mm PASID 1:n with sva domains
mm: Deprecate pasid field

arch/x86/kernel/traps.c | 2 +-
.../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 12 ++---
drivers/iommu/intel/svm.c | 8 +--
drivers/iommu/iommu-sva.c | 50 ++++++++++++-------
include/linux/iommu.h | 19 +++++--
include/linux/mm_types.h | 3 +-
kernel/fork.c | 1 -
mm/init-mm.c | 3 --
8 files changed, 58 insertions(+), 40 deletions(-)

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2.17.1