Re: [Xen-devel] Is driver domain a dom0 or domU

["pradeep singh rautela" <rautelap@xxxxxxxxx>]

On 5/17/07, Petersson, Mats <Mats.Petersson@xxxxxxx> wrote:
> > -----Original Message-----
> > From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
> > [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of
> > pradeep singh rautela
> > Sent: 17 May 2007 10:29
> > To: xen-devel
> > Subject: [Xen-devel] Is driver domain a dom0 or domU
> >
> > The wiki link at
> > http://wiki.xensource.com/xenwiki/DriverDomain?highlight=%28dr
> > iver%29%7C%28domain%29
> >
> > says it is domU.
> > I don't think so.
> > driver domain is a priviliged dom0 domain with backend driver along
> > with the actual hardware driver part for the device it serves.
>
> A driver domain is ANY domain that has (direct) access to hardware. In
> the common case, only Dom0 is a driver domain, but if you assign a PCI
> device to another domain, that becomes a driver domain.
>
> Only Dom0 [1] is PRIVILEGED, in the sense that only Dom0 can create,
> destroy and otherwise manage other domains. DomU is any domain that
> isn't Dom0.
>
> [1] In the current implementation of Xen. There is no technical reason
> why more domains couldn't be privileged. Just like you can have multiple
> users in a Linux-system that are "root" users (just that there can
> obviously only be one that is CALLED root, but you can have any number
> of different users that have root privilege). In Xen, there is a macro
> called "IS_PRIV" (from memory). It checks a variable within the domain
> structure that says whether the domain is privileged or not. Currently,
> this variable is only set in one place, and that is during Dom0
> creation. But with a suitable interface to change this variable, any
> other domain could technically be made into a "privileged domain" (it
> still would of course not be Dom0, as there can only be ONE Dom0 - that
> is the domain with ID number zero!).
That was really some good info Mats.
Thanks a lot

--psr
> --
> Mats
> >
> > Is my understanding correct?
> >
> > Thank you
> > --psr
> >
> > --
> > ---
> > pradeep singh rautela
> >
> > "Genius is 1% inspiration, and 99% perspiration" - not me :)
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-devel
> >
> >
> >

--
---
pradeep singh rautela

"Genius is 1% inspiration, and 99% perspiration" - not me :)

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