Re: ZONE_DMA (was: Re: 2.6.19 -mm merge plans)

James Bottomley
2006-09-21T16:00:19Z

On Thu, 2006-09-21 at 02:03 +0100, Alan Cox wrote:
> IOMMUs don't always help. They IOMMU aperture on AMD64 for example is
> too high to help devices with below 32bit limits.

That's because it's not an IOMMU; it's a GART. A true IOMMU separates
the machine physical and bus physical address spaces ... a GART merely
remaps a hole in physical address space.

James