RE: [Xen-users] Xen support for AMD's IOMMU

["Petersson, Mats" <Mats.Petersson@xxxxxxx>]

> -----Original Message-----
> From: M.A. Williamson [mailto:maw48@xxxxxxxxxxxxxxxx] On 
> Behalf Of Mark Williamson
> Sent: 26 February 2007 17:40
> To: xen-users@xxxxxxxxxxxxxxxxxxx
> Cc: Petersson, Mats; Daniel McAllansmith
> Subject: Re: [Xen-users] Xen support for AMD's IOMMU
> 
> > > What is the status of support for AMD's (hardware/Pacifica)
> > > IOMMU in xen
> > > 3.0.2/3/4?
> >
> > Considering that we haven't yet got a part available with IOMMU, the
> > software to fullfill that function is pretty much a moot 
> point, right?
> 
> There's some sort of memory permissions table for PCI devices 
> though, isn't 
> there?  I vaguely remember it being in the arch manual, but I haven't 
> actually known any software use it (at least in the context of Xen!)

Yes, that's called "DEV" or "Device Exclusion Vector", and I'm also
unaware of any software that is commonly available that uses this. It
doesn't actually solve the most commonly requested feature in IOMMU,
which is the ability to run a HVM-guest using a PCI-device, and I wasn't
really considering the "security aspect" of IOMMU when I wrote my answer
[and the DEV feature is definitely not usable to solve the PCI-device in
HVM problem]. 

--
Mats
> 
> Cheers,
> Mark
> 
> > As to a direct answer to the question: There is no AMD 
> IOMMU software in
> > 3.0.{2,3,4}. There's been a patch supplied by Mark 
> Langsdorf to use the
> > GART in the current AMD64 architecture for IOMMU operations 
> (same way as
> > the Linux kernel itself uses this portion of the chip). 
> This is NOT to
> > be confused with the REAL IOMMU design.
> >
> > --
> > Mats
> >
> > > Thanks
> > > Daniel
> > >
> > > _______________________________________________
> > > Xen-users mailing list
> > > Xen-users@xxxxxxxxxxxxxxxxxxx
> > > http://lists.xensource.com/xen-users
> >
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-users
> 
> -- 
> Dave: Just a question. What use is a unicyle with no seat?  
> And no pedals!
> Mark: To answer a question with a question: What use is a skateboard?
> Dave: Skateboards have wheels.
> Mark: My wheel has a wheel!
> 
> 
> 



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