Re: [Xen-devel] [PATCH v4 5/5] amd/iommu: skip bridge devices when updating IOMMU page tables

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 14.11.18 at 12:57, <roger.pau@xxxxxxxxxx> wrote:
> Bridges are not behind an IOMMU, and are already special cased and
> silently skipped in amd_iommu_add_device. Apply the same special
> casing when updating page tables.

But bridges also don't issue I/O on their own if I'm not mistaken. So
what I'm missing here is a word on the benefit of this change. I also
question the "silently" in your wording, seeing the AMD_IOMMU_DEBUG()
there.

The code change itself looks fine to me, albeit personally I'd prefer
if it fully matched the other conditional (i.e. if you flipped the
operands of && ). Of course the special casing of the hardware
domain here is somewhat odd anyway.

Jan



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