Re: [PATCH 1/1] iommu: add a dma remap fault reason.

[Don Dutile]

On 03/07/2013 01:31 PM, Don Dutile wrote:
> cc-ing the upstream iommu-list
>
> On 03/05/2013 09:43 PM, Li, Zhen-Hua wrote:
> > The number of dma fault reasons in intel's document are from 1 to 0xD, but in dmar.c I cannot find fault reason 0xD.
> >
> > In this document:
> > Intel Virtualization Technology for Directed I/O Architecture Specification
> > http://download.intel.com/technology/computing/vptech/Intel(r)_VT_for_Direct_IO.pdf
> >
> > Chapter 4. Support For Device-IOTLBs
> >
> > Table 6. Unsuccessful Translated Requests
> >
> > There is fault reason for 0xD not listed in kernel:
> > Present context-entry used to process translation request
> > specifies blocking of Translation Requests (Translation Type (T)
> > field value not equal to 01b).
> >
> > So I think 0xD should be added.
> >
> > Signed-off-by: Li, Zhen-Hua<zhen-hual@xxxxxx>
> > ---
> > drivers/iommu/dmar.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
> > index dc7e478..e5cdaf8 100644
> > --- a/drivers/iommu/dmar.c
> > +++ b/drivers/iommu/dmar.c
> > @@ -1083,6 +1083,7 @@ static const char *dma_remap_fault_reasons[] =
> > "non-zero reserved fields in RTP",
> > "non-zero reserved fields in CTP",
> > "non-zero reserved fields in PTE",
> > + "PCE for translation request specifies blocking",
> > };
> >
> > static const char *irq_remap_fault_reasons[] =

Yes, the multiple tables, some short, some long, duplicating error codes,
and in this case, putting it out of order, helped this case!

btw -- Suresh not at intel any longer (email bounces)

So, patch looks good to me. Although, I don't know of any code that
actually sets a translation to 'block translation'.... but
for completeness, rest of code does range checking & sizing such
that it's doing the right thing.
The only other thing I can surmize from the dmar.c file is if one
of these faults occurred, an 'unknown error' would have been outputted.

cheers.. Don
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