> -----Original Message-----
> From: Liang Yang [mailto:multisyncfe991@hotmail.com]
> Sent: 03 May 2007 17:28
> To: Petersson, Mats; Koripella Srinivas; xen-devel@lists.xensource.com
> Subject: Re: [Xen-devel] DomU-DomU Event Channel
>
> If you assign a DomU "driver-domain", does that cause unnecessary
> communication overhead between your driver domain and domain0
> as the native
> driver modules still reside in the domain0? or you will put
> your native
> driver in domU together with your BE driver?
Short answer: No.
Long answer:
The definition of "driver domain" (at least as used here) is a domain
that has acces directly to the actual hardware, and thus can act as a
back-end for another domain with frontend drivers. There is normally no
communication between Dom0 and a driver-domain, certainly not in the
context of accessing the hardware assigned to the driver-domain, but
there can (usually is) some communication where the driver-domain uses
Dom0 to communicate to hardware that it itself doesn't own.
For example, if we give a network card (but no other hardware devices)
to a DomU (name this "NetDomU"), and assign another DomU "UseDomU" to
use the network hardware in "NetDomU" via the normal BE/FE driver pair.
NetDomU can still not access the HARD-DISK, since it's not been given
access to any hard-disk controller. So if NetDomU is reading/writing to
a file for some reason, it communicates with Dom0 to do this.
UseDomU will probably also use Dom0 to do disk-io, but the network
traffic (at least on some interface) doesn't pass Dom0, only NetDomU.
I hope this clarfies things.
--
Mats
>
> Liang
>
> ----- Original Message -----
> From: "Petersson, Mats" <Mats.Petersson@amd.com>
> To: "Koripella Srinivas" <talkwithsrinivas@yahoo.co.in>;
> <xen-devel@lists.xensource.com>
> Sent: Thursday, May 03, 2007 9:01 AM
> Subject: RE: [Xen-devel] DomU-DomU Event Channel
>
>
> > -----Original Message-----
> > From: xen-devel-bounces@lists.xensource.com
> > [mailto:xen-devel-bounces@lists.xensource.com] On Behalf Of
> > Koripella Srinivas
> > Sent: 03 May 2007 16:55
> > To: xen-devel@lists.xensource.com
> > Subject: [Xen-devel] DomU-DomU Event Channel
> >
> > Hi,
> > I want to move the qemu emulation code running in domain0 and
> > move it to another domain for a particular device for a HVM
> > guest. As part of that i want to know if it is possible to
> > set up an event channel between 2 domU's.
>
> I would have thought so, as you can assign a DomU
> "driver-domain" to be
> the backend to another DomU - I take it that this would be
> roughly what
> you're trying to do as well, except for a HVM-domain.
>
> [.This is pure speculation, based on my understanding of how
> domains talk
> to each other combined with the functinality described by "xm
> block/net-attach"].
>
> --
> Mats
> >
> > thanks
> >
>
>
>
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