Re: [PATCH] reserved-ram for pci-passthrough without VT-d capable hardware

[Dor Laor <dor.laor@qumranet.com>]

Andrea Arcangeli wrote:
> On Wed, Jul 30, 2008 at 11:50:43AM +0530, Amit Shah wrote:
>   
>> * On Tuesday 29 July 2008 18:47:35 Andi Kleen wrote:
>>     
>>>> I'm not so interested to go there right now, because while this code
>>>> is useful right now because the majority of systems out there lacks
>>>> VT-d/iommu, I suspect this code could be nuked in the long
>>>> run when all systems will ship with that, which is why I kept it all
>>>>         
>>> Actually at least on Intel platforms and if you exclude the lowest end
>>> VT-d is shipping universally for quite some time now. If you
>>> buy a Intel box today or bought it in the last year the chances are pretty
>>> high that it has VT-d support.
>>>       
>> I think you mean VT-x, which is virtualization extensions for the x86 
>> architecture. VT-d is virtualization extensions for devices (IOMMU).
>>     
>
> I think Andi understood VT-d right but even if he was right that every
> reader of this email that is buying a new VT-x system today is also
> almost guaranteed to get a VT-d motherboard (which I disagree unless
> you buy some really expensive toy), there are current large
> installations of VT-x systems that lacks VT-d and that with recent
> current dual/quadcore cpus are very fast and will be used for the next
> couple of years and they will not upgrade just the motherboard to use
> pci-passthrough.
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>   

In addition KVM is used in embedded too and things are slower there, we 
know of a specific use case (production) that demands
1:1 mapping and can't use VT-d