I am running into a DMA issue that appears to be a conflict between ACS and IOMMU. As per the documentation I can find, the IOMMU is supposed to create reserved regions for MSI and the memory window behind the root port. However looking at reserved_regions I am not seeing that. I only see the reservation for the MSI. So for example with an enabled NIC and iommu enabled w/o passthru I am seeing: # cat /sys/bus/pci/devices/0000\:83\:00.0/iommu_group/reserved_regions 0x00000000fee00000 0x00000000feefffff msi Shouldn't there also be a memory window for the region behind the root port to prevent any possible peer-to-peer access?
