Subject: Re: wpi0: Full open source driver at openbsd
To: None <>
From: David Young <>
List: tech-kern
Date: 10/05/2007 12:23:17
On Fri, Oct 05, 2007 at 12:51:56PM -0400, der Mouse wrote:
> > If your network card can access memory (and it _must_ be able to, or
> > it would be mostly useless), then it _is_ potentially dangerous.  It
> > could probably fairly easily dump anything in RAM over the network to
> > some other machine.
> Only if the DMA mapping is set up to allow it access to that RAM - or
> if your machine is so stupidly designed that a DMA bus master can
> access memory it hasn't specifically been set up with access to.  While
> there are undoubtedly such systems, I would hope that nothing using a
> wpi would be quite that low-end.

It is an exceptional machine that lets you protect memory from bus masters
in this way.  You may find an IOMMU in most 64-bit, non-x86 machines.

AMD says it will introduce an IOMMU in 2009 (used to say 2007).  In the
mean time, AMD's AGP GART can rudimentarily protect memory from PCI
bus masters.


David Young             OJC Technologies      Urbana, IL * (217) 278-3933 ext 24