Re: [Xen-devel] Re: PCI Passthrough using GART on AMD CPUs?

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

The functionality of that patch is to allow dom0 to use the GART as a target
aperture for 32-bit PCI devices to access memory above 4GB. The GART cannot
possibly implement the functionality of the new AMD or Intel IOMMUs, as it
does not intercept *every* DMA access issued by guest-controlled devices.
The patch you would like to see is an impossibility.

 -- Keir

On 16/5/08 05:05, "Yosuke Iwamatsu" <y-iwamatsu@xxxxxxxxxxxxx> wrote:

> Hi,
> 
> I've found an old post about GART as mini-IOMMU. Please see below.
> As far as I read, the patch was not checked in because it was not
> complete. If the code comes to the main tree, there is no reason
> we don't support PCI hotplug for GART.
> 
> http://xen.markmail.org/message/ylcrn2qgvgzlpajd
> 
> Thanks,
>   Yosuke
> 
> Li, Xin B wrote:
>> we don't have that kind of environment, but the code is designed to support
>> both platform.
>> -Xin 
>> 
>>> -----Original Message-----
>>> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
>>> [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of
>>> Jeff Williams
>>> Sent: 2008年5月16日 9:28
>>> To: xen-devel@xxxxxxxxxxxxxxxxxxx
>>> Subject: [Xen-devel] Re: PCI Passthrough using GART on AMD CPUs?
>>> 
>>> Han, Weidong <weidong.han <at> intel.com> writes:
>>> 
>>>>> Also can PCI hotplug work as with VT-d?
>>>> Yes. VT-d hotplug has been supported. docs/misc/vtd.txt
>>> tells you how to
>>>> use it.
>>>> 
>>>> Randy (Weidong)
>>>> 
>>> Actually I've read this already but thanks. I was wondering if
>>> PCI hotplug 
>>> could be make to work with the GART mini-IOMMU on the AMD
>>> platform instead of
>>> using VT-d.
>>> 
>>> 
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>>> 
>> 
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> 
> 
> 
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