Issue when the kernel parameter intel_iommu=on is being used

Hello,



I am using DPDK 1.5 for development of host pmd for device “Connect X3”.



I am observing issue  while the ConnectX3 device DMA to a memory which is
allocated with rte_memzone_reserve_aligned() API .

The issue(please refer ERROR below) has been observed if the system runs
with the kernel parameter “intel_iommu=on”.



ERROR :

dmar: DRHD: handling fault status reg 302

dmar: DMAR:[DMA Write] Request device [01:00.0] fault addr 4f883000

DMAR:[fault reason 01] Present bit in root entry is clear


The reported "fault Addr" is the physical address which was returned by the
Above API.



I don’t see any issue with the same code when the system up with kernel
parameter intel_iommu=off.




Can you share your comments on this issue?


Thanks in advance

Sri