[PATCH v2 0/3] arm-smmu: select suitable IOVA

[Shyam Saini]

Hi,

Currently, the MSI_IOVA_BASE address is hard-coded to 0x80000000,
assuming that all platforms have this address available for MSI IOVA
reservation. However, this is not always the case, as some platforms
reserve this address for other purposes. Consequently, these platforms
cannot reserve the MSI_IOVA_BASE address for MSI.

There was an [1] attempt to fix this problem by passing the MSI IOVA
base as a kernel command line parameter.

This patch series aims to address the issue by introducing a new DTS
property, "arm,smmu-faulty-msi-iova" which can be used to hold faulty
MSI IOVA address. This property can be passed to ARM SMMU drivers
via device tree so that the drivers can select appropriate MSI IOVA base
address which doesn't intersect with the faulty MSI IOVA address.

This approach accommodates platforms that do not have the default MSI base address
available for MSI reservation.

[1]: https://lore.kernel.org/lkml/20200914181307.117792-1-vemegava@linux.microsoft.com/

Thanks,
Shyam

---
v2:
- add new dts property to hold faulty MSI IOVA and select appropriate
  MSI IOVA address

v1:
Link: https://lore.kernel.org/linux-iommu/20250116232307.1436693-1-shyamsaini@linux.microsoft.com/

Shyam Saini (3):
  arm-smmu: move MSI_IOVA macro definitions
  arm-smmu: select suitable MSI IOVA
  dt-bindings: iommu: add "arm,smmu-faulty-msi-iova" property

 .../bindings/iommu/arm,smmu-v3.yaml           |  8 +++
 .../devicetree/bindings/iommu/arm,smmu.yaml   |  8 +++
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   |  9 +++-
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  3 --
 drivers/iommu/arm/arm-smmu/arm-smmu.c         | 10 ++--
 drivers/iommu/virtio-iommu.c                  |  2 -
 include/linux/iommu.h                         | 52 +++++++++++++++++++
 7 files changed, 81 insertions(+), 11 deletions(-)

-- 
2.34.1