Is Intel VT-d at all useful if direct device attachement is not required?

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It seems that one disadvantage of Intel i3 processors versus their more capable i5 and i7 brothers is the consistent lack of VT-d support. I understand the basics of IOMMU hardware and how it would benefit people that want their virtual machines to access their hardware directly.

What I am wondering is whether VT-d has any other uses besides that. Could it benefit in any way a user that is content letting their host OS handle the hardware? For example, is there any hypervisor that uses VT-d e.g. to speed-up paravirtualized devices somehow? Or, say, to run nested guests?

Note: I am not asking for either speculation or shopping advice - just concrete information, if possible...

thkala

Posted 2012-06-28T22:38:16.330

Reputation: 1 769

1The K series core i5 and i7 lack this as well, for some reason. – Journeyman Geek – 2012-06-29T00:22:26.257

Answers

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No, there is not any benefit. VT-d (IOMMU) is just re-mapping of the device, it's pretty simple, actually re-mapped HW becomes unbinded and then host OS doesn't know about this device.

OT: For everybody who's checking his CPU, this is useful: http://ark.intel.com/search/advanced?VTD=true ... and beware of C1 stepping!

dmnc

Posted 2012-06-28T22:38:16.330

Reputation: 398

1This does indeed seem to be the answer from what I have been able to gather... – thkala – 2012-10-12T16:47:05.767