On Thu, 2014-04-10 at 08:46 +0000, Woodhouse, David wrote:
> On Thu, 2014-04-10 at 09:15 +0200, Joerg Roedel wrote:
> > [+ David, VT-d maintainer ]
> > 
> > Jiang, David, can you please have a look into this issue?
> > 
> 
> > > > >> > > > > DMAR:[fault reason 02] Present bit in context entry is clear
> > > > >> > > > > dmar: DRHD: handling fault status reg 602
> > > > >> > > > > dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr 7f61e000
> 
> That "Present bit in context entry is clear" fault means that we have
> not set up *any* mappings for this PCI device… on this IOMMU.
> 
> > > Yes, specifically (finally done bisecting):
> > > 
> > > commit 2e45528930388658603ea24d49cf52867b928d3e
> > > Author: Jiang Liu <jiang.liu@linux.intel.com>
> > > Date:   Wed Feb 19 14:07:36 2014 +0800
> > > 
> > >     iommu/vt-d: Unify the way to process DMAR device scope array
> 
> This commit is about how we decide which IOMMU a given PCI device is
> attached to.
> 
> Thus, my first guess would be that we are quite happily setting up the
> requested DMA maps on the *wrong* IOMMU, and then taking faults when the
> device actually tries to do DMA.
> 
> However, I'm not 100% convinced of that. The fault address looks
> suspiciously like a true physical address, not a virtual bus address of
> the type that we'd normally allocate for a dma_map_* operation. Those
> would start at 0xfffff000 and work downwards, typically.
> 
> Do you have 'iommu=pt' on the kernel command line? 

No.

> Can I see the full
> dmesg as this system boots, and also a copy of the DMAR table?

Attaching a dmesg from one of the kernels that boots. It doesn't appear
to have much of the related information... is there any debug config
option I can enable that might give you more data?