Re: [Xen-users] pci passthrough and svm

[Paul Schulze <avlex@xxxxxxx>]

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Forgot to CC, so here is a copy of my answer.

Forwardl:

> Von: Paul Schulze <avlex@xxxxxxx>
> Datum: 10. September 2008 19:33:57 MESZ
> An: mpower@xxxxxxxxxxxxxxxxxx
> Betreff: Re: [Xen-users] pci passthrough and svm
>
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> Hi Mike,
>
> The bad news (as far as my understanding of this goes, no clue if  
> its technically correct): At the moment, there is no AMD equivalent  
> for VT-d. AMD SVM is a CPU virtualization extension, comparable  
> with IVT. VT-d, is an IOMMU, that probably resides with the memory  
> controller and handles virtualization and protection of DMA. So in  
> case of an Intel CPU on the mainboard (no clue if it needs special  
> support on the CPU on top of that). AMD first announced to  
> implement an equivalent to that technology quite a few years ago,  
> but up until now there are no products I can think of that include  
> such a feature. However, CPUs, supporting it are rumored to be  
> released early in 2009, so there is hope (for me too, because my  
> Xen server is built on AMD hardware as well).
> And the good news: Even though there is no IOMMU support on AMD  
> platforms, it is possible to pass PCI hardware through to a  
> paravirtualized DomU. This feature does not depend on VT-d, with  
> the exception of PCI passthrough to HVM domains (to Windows for  
> example). Like I said, I am on an AMD platform and I have succeeded  
> in passing though multiple devices, including USB controllers,  
> audio devices and network devices (no graphics cards though).  
> However, when passing PCI devices to a paravirtualized domain,  
> always remember that there is no protection against faulty or  
> malicious memory access due to the missing IOMMU, enabling the DomU  
> to potentially access even Dom0 memory.
> Cheers,
>
>
> Paul.
> - --
> Paul Schulze
> Mail: avlex  gmx  net ($1@$2.$3)
> Public Key: http://solaris-net.dyndns.org/keys/key_avlex.asc
>
> "Making mistakes is human,
> but to really screw things up, you need Computers"
>
>
>
> Am 10.09.2008 um 17:50 schrieb Mike Power:
>
> > I noticed talk of pci passthrough seems to always be in reference  
> > to VT_D which from my understanding is an intel technology.  Is  
> > there equivalent and xen enabled functionality from AMD's svm  
> > technology?
> > Mike Power
> >
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-users
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- --
Paul Schulze
Mail: avlex  gmx  net ($1@$2.$3)
Public Key: http://solaris-net.dyndns.org/keys/key_avlex.asc

"Making mistakes is human,
but to really screw things up, you need Computers"

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