I have an ubuntu guest running on kvm , and I am passing it 10 qemu emulated nvme drives <iommu model='intel'> <driver intremap='on' eim='on'/> </iommu> <qemu:arg value='pcie-root-port,id=pcie-root-port%d,slot=%d'/> <qemu:arg value='nvme,drive=NVME%d,serial=%s_%d,id=NVME%d,bus=pcie-root-port%d'/> kernel Linux node-1 5.15.0-56-generic #62-Ubuntu SMP ----- x86_64 x86_64 x86_64 GNU/Linux kernel command line intel_iommu=on I have attached these drives to vfio-pcie. when I try to send IO commands to these drives VIA a userspace nvme driver using VFIO I get [ 1474.752590] DMAR: DRHD: handling fault status reg 2 [ 1474.754463] DMAR: [DMA Read NO_PASID] Request device [0b:00.0] fault addr 0xffffe000 [fault reason 0x06] PTE Read access is not set Can someone explain to me what's happening here ?