Re: [Xen-users] IOMMU Domain for Dom0

[Alex Merritt <merritt.alex@xxxxxxxxx>]

Hi,

2011/6/22 sploving <sploving1@xxxxxxx>:
>
>
>
> AtÂ2011-06-21Â12:17:56ï"AlexÂMerritt"Â<merritt.alex@xxxxxxxxx>Âwrote:
>
>>Hello,
>>
>>I'veÂbeenÂexperimentingÂwithÂVT-dÂsupportedÂPCI-passthroughÂinÂXenÂfor
>>HVMÂguests,ÂandÂwasÂwonderingÂifÂitÂisÂpossibleÂtoÂcreateÂanÂIOMMU
>>domainÂforÂDom0ÂasÂwell.ÂI'mÂnotÂsureÂifÂI'mÂaskingÂtheÂquestion
>>correctly,ÂbutÂtoÂavoidÂchangingÂaÂbare-metalÂdriverÂforÂanÂI/OÂdevice
>>toÂtranslateÂsystemÂmemoryÂaddressesÂusedÂbyÂaÂDMAÂengine,ÂwouldÂI
>>insteadÂbeÂableÂtoÂallowÂtheÂIOMMUÂtoÂtransparentlyÂtranslate
>>addressesÂjustÂlikeÂforÂguestÂVMs,ÂbutÂwithinÂDom0?
> why put the IOMMU within Dom0? not in the driver domain?

I'm using research code, which currently requires the management
extension and driver to exist within the same domain. IOMMUs are meant
for guest VMs as far as I can tell. They can be used as driver
domains, too, but (unless I'm mistaken) cannot use the management
interfaces available in Dom0.

My driver domain is also Dom0 at the moment.

> ÂSomeÂsearchingÂand
>>readingÂofÂtheÂwikiÂpagesÂonÂxen.orgÂtellsÂmeÂtheÂanswerÂisÂ"no".ÂBut
>>IÂcannotÂdetermineÂifÂthisÂisÂpurelyÂbecauseÂtheÂimplementationÂwithin
>>theÂVMMÂdoesn'tÂexist,ÂorÂbecauseÂitÂisÂthatÂDom0ÂisÂpara-virtualized
>>andÂthusÂcannotÂuseÂVT-dÂwithoutÂVT-x.ÂI'mÂsuspectingÂitÂisÂnotÂthe
>>latter,ÂasÂtheÂVTdHowToÂwikiÂpageÂhintsÂPVÂguestsÂmayÂuseÂVT-dÂandÂthe
>>IntelÂmanualÂforÂVT-dÂdescribesÂOSÂdevelopersÂmayÂtakeÂadvantageÂof
>>thisÂextension.
>>
>>MyÂimmediateÂinterestÂisÂmoreÂtoÂseeÂifÂitÂ"canÂbeÂdone"ÂviaÂaÂhackÂor
>>something,ÂnotÂnecessarilyÂwhetherÂitÂwouldÂmakeÂsense
> forÂXenÂto
>>supportÂthisÂinÂtheÂfuture.
>>
> You should ask this question in xen-dev list.

Okay, I'll do that. I'm new to these mailing lists, and wasn't sure
where to start. Thanks.

>>I'mÂusingÂXenÂ4.1.1ÂandÂpv-opsÂlinuxÂ(notÂupstream)Â2.6.32.40ÂonÂan
>>IntelÂX5660ÂwithÂa
> TylersburgÂchipset.
>>
>>Thanks!
>>Alex
>>
>>_______________________________________________
>>Xen-usersÂmailingÂlist
>>Xen-users@xxxxxxxxxxxxxxxxxxx
>>http://lists.xensource.com/xen-users

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