Re: Facing "PTE Read access is not set" VFIO NVMe

[Alberto Faria]

On Thu, Dec 22, 2022 at 1:16 PM Major Saheb <majosaheb@gmail.com> wrote:
> Hi All,
>
> 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 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

Does this patch happen to fix it?

https://lore.kernel.org/qemu-devel/20220905000021.157613-1-afaria@redhat.com/

Alberto

>
> I have narrowed it down to issuing the first command to NVMe (which is
> Identify controller in this case), and it seems the DMA is failing due
> to
> inaccessible IO page table. I have also tried adding
> 'iommu_platform=on,ats=on' which I found at
> https://wiki.qemu.org/Features/VT-d and it says the following
>
> 2022-12-22T11:29:07.001178Z qemu-system-x86_64: -device
> nvme,drive=NVME0,serial=akqkvcl-0_0,id=NVME0,bus=pcie-root-port0,iommu_platform=on:
> Property 'nvme.iommu_platform' not found
> 2022-12-22T11:21:48.281876Z qemu-system-x86_64: -device
> nvme,drive=NVME0,serial=akqkvcl-0_0,id=NVME0,bus=pcie-root-port0,iommu_platform=on,ats=on:
> Property 'nvme.ats' not found
>
> -R
>