[RTnet-developers] IOMMU compatibility

[Jan K. <jan...@we...>]

Hi,

git head now contains a framework for making RTnet drivers compatible
with Linux using an IOMMU (VT-d in Intel-speak). Drivers can now
register callbacks invoked on every rtskb creation or deletion and
map/unmap those buffers outside the RT code paths. This is required as
services like dma_map_single run into Linux locking when the IOMMU is
active.

So far rt_igb and the new rt_e1000e are making use of this. And that
means you can use those drivers aside KVM on a Xenomai host (for
required I-pipe and Xenomai patches see [1].

I suspect I broke some older kernels along these changes. If you find
some regression, please report or even post patches.

Thanks,
Jan

[1] http://thread.gmane.org/gmane.linux.kernel.adeos.general/1898