On 31 December 2022 10:13:37 GMT, Yi Liu <yi.l.liu@xxxxxxxxx> wrote: >On 2022/12/31 04:07, David Woodhouse wrote: >> >> >> On 30 December 2022 19:20:42 GMT, Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: >>> Hi Major, >>> >>> Thanks for the report! >>> >>> On Wed, Dec 21, 2022 at 08:38:46PM +0530, Major Saheb wrote: >>>> 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 ? > >You can enable iommu debugfs (CONFIG_INTEL_IOMMU_DEBUGFS=y) to check >the mapping. In this file, you can see if the 0xffffe000 is mapped or >not. > >/sys/kernel/debug/iommu/intel/domain_translation_struct My first guess would be that it *was* using queues mapped at that address, but was taken out of the IOMMU domain to be given to userspace, without stopping them.
