[Xen-devel] Re: [PATCH 2 of 6] amd iommu: Cleanup iommu pci capabilites detection

[Wei Wang2 <wei.wang2@xxxxxxx>]

On Friday 11 November 2011 10:33:07 Jan Beulich wrote:
> >>> On 09.11.11 at 16:50, Wei Wang <wei.wang2@xxxxxxx> wrote:
> >
> > # HG changeset patch
> > # User Wei Wang <wei.wang2@xxxxxxx>
> > # Date 1320851997 -3600
> > # Node ID 4b115815bc13e4f2a3a178f3de7477ecf46cb44b
> > # Parent  4769713326a876c25bdc0f9d1f90594f90fba9c5
> > amd iommu: Cleanup iommu pci capabilites detection.
> > * Define new structure to represent capability block.
> > * Remove unnecessary read for unused information.
> > * Add sanity check into get_iommu_capabilities.
> > * iommu capability offset is 16 bit not 8 bit, fix that.
>
> Does this imply that the capability can reside in extended config space?
> If so, all code paths using this will need revisiting with regard to
> extended config space possibly being inaccessible until early Dom0
> initialization.

Jan,
This is just an inconsistency issue with iommu specification as in IVHD 
header, it has been defined as 16 bit value. In reality, both current and 
next generation amd iommu will not have this capability in  extended pci 
config space. 

Thanks,
Wei

> Jan
>
> > Signed-off-by: Wei Wang <wei.wang2@xxxxxxx>




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