[PATCH v2 0/3] iommu/s390: add support for IOMMU passthrough

Matthew Rosato
2024-12-13T22:49:58Z

This series introduces the ability for certain devices on s390 to bypass
a layer of IOMMU via the iommu.passthrough=1 option. In order to enable
this, the concept of an identity domain is added to s390-iommu. On s390,
IOMMU passthrough is only allowed if indicated via a special bit in s390
CLP data for the associated device group, otherwise we must fall back to
dma-iommu.

Changes for v2:
- Remove ARCH_HAS_PHYS_TO_DMA, use bus_dma_region
- Remove use of def_domain_type, use 1 of 2 ops chosen at init

Matthew Rosato (3):
s390/pci: check for relaxed translation capability
s390/pci: store DMA offset in bus_dma_region
iommu/s390: implement iommu passthrough via identity domain

arch/s390/include/asm/pci.h | 2 +-
arch/s390/include/asm/pci_clp.h | 4 +-
arch/s390/pci/pci.c | 6 ++-
arch/s390/pci/pci_bus.c | 18 +++++++
arch/s390/pci/pci_clp.c | 1 +
drivers/iommu/s390-iommu.c | 95 +++++++++++++++++++++++++--------
6 files changed, 99 insertions(+), 27 deletions(-)

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2.47.1