Modern platforms have more than one IOMMU. Each IOMMU has its own feature set. Some of these features must be consistent among IOMMUs. Otherwise, these differences can lead to improper behavior in the system. On the other hand, for some features, each IOMMU can have different capacity values. So, different actions are required to deal with the inconsistencies depending on the IOMMU features.
Currently, some inconsistencies are ignored by the IOMMU driver. This patchset checks IOMMU capabilities and extended capabilities centralizedly during boot and take different actions according to the impacts caused by the mismatches. For example: 1. Disable Shared Virtual Memory. 2. Use common capacity values (normally the lowest capacity value) for all IOMMUs. 3. Report feature mismatches. Detailed information on the IOMMU Capability / Extended Capability can be found in Intel VT-d Specification. Link: https://software.intel.com/sites/default/files/managed/c5/15/vt-directed-io-spec.pdf ChangeLog: - Change from v3 to v4: 1. fix the build error for when only enabled irq remapping. - Change from v2 to v3: 1. fix the wrong macro names and rebase to v5.10. - Change from v1 to v2: 1. Add missing cap/ecaps for audit. 2. Refactor function/macros overal suggested by Lu, Baolu. 2. Skip audit for gfx dedicated IOMMU. 3. Change commit message. Kyung Min Park (3): iommu/vt-d: Audit IOMMU Capabilities and add helper functions iommu/vt-d: Move capability check code to cap_audit files iommu/vt-d: Disable SVM in the platform when IOMMUs have inconsistencies drivers/iommu/intel/Makefile | 4 +- drivers/iommu/intel/cap_audit.c | 219 ++++++++++++++++++++++++++++ drivers/iommu/intel/cap_audit.h | 132 +++++++++++++++++ drivers/iommu/intel/iommu.c | 85 ++--------- drivers/iommu/intel/irq_remapping.c | 8 + drivers/iommu/intel/svm.c | 3 +- include/linux/intel-iommu.h | 39 ++--- 7 files changed, 395 insertions(+), 95 deletions(-) create mode 100644 drivers/iommu/intel/cap_audit.c create mode 100644 drivers/iommu/intel/cap_audit.h -- 2.17.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu