On Fri, Jan 25, 2008 at 09:45:07PM +1100, Michael Ellerman wrote:

Citing "release early release often", I'm posting this now as a mega-patch
to get people looking at it. I'll try to split it up and make it look a
little prettier before submitting it.

The intent of this patch is to setup (on certain machines) a "static" IOMMU
mapping of all of memory, to reduce the overhead of the IOMMU. If anyone has
a better name than "static" I'm all ears.

So instead of having an IOMMU window that we use to temporarily map things
in and out of DMA'able space, at boot we create a 1:1 mapping for all of
memory. This obviously only works for devices that can do 64-bit DMA.

I don't get it. Why not disable the iommu instead?


-Olof