[vfio-users] VFIO: DMAR kernel

[Alex Williamson]

On Thu, 5 May 2016 15:40:29 +0000
"MEHAN, MUNISH" <mm6021 at att.com> wrote:

> All,
> 
>  I am trying to load a vfio driver for the Intel VFs. I am seeing the following error from kernel. I tried all the grub options with iommu=on,iommu=pt, intel_iommu=on, intel_iommu=pt,isolcpus=2,4 etc.
> 
> Can someone suggest what can be issue here and how I can mitigate this.
> 
> [Wed May  4 12:13:47 2016] dmar: DMAR:[DMA Write] Request device [86:00.1] fault addr 1f3521a000
> [Wed May  4 12:13:47 2016] DMAR:[fault reason 05] PTE Write access is not set
> [Wed May  4 12:13:49 2016] dear: DMAR:[DMA Write] Request device [86:00.1] fault addr 1f35219000
> [Wed May  4 12:13:49 2016] DMAR:[fault reason 05] PTE Write access is not set
> [Wed May  4 12:13:49 2016] dmar: DMAR:[DMA Write] Request device [86:00.1] fault addr 1f35218000
> [Wed May  4 12:13:49 2016] DMAR:[fault reason 05] PTE Write access is not set
> [Wed May  4 12:13:51 2016] dmar: DMAR:[DMA Write] Request device [86:00.1] fault addr 1f35217000
> [Wed May  4 12:13:51 2016] DMAR:[fault reason 05] PTE Write access is not set
> [Wed May  4 12:13:53 2016] dmar: DMAR:[DMA Write] Request device [86:00.1] fault addr 1f35216000
> [Wed May  4 12:13:53 2016] DMAR:[fault reason 05] PTE Write access is not set
> [Wed May  4 12:13:55 2016] dmar: DMAR:[DMA Write] Request device [86:00.1] fault addr 1f35215000
> [Wed May  4 12:13:55 2016] DMAR:[fault reason 05] PTE Write access is not set

You get this while the VM is running?  The fault address is up past
124GB, is it safe to assume you are not running a 124GB VM?  Please
provide host dmesg booted without iommu=pt and QEMU invocation
(available in /var/log/libvirt/qemu/ if using libvirt).  Thanks,

Alex