WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] Does XEN use TUN/TAP interface?

On Sun, Mar 16, 2008 at 06:21:51PM +0100, Daniel Stodden wrote:
> On Sun, 2008-03-16 at 17:12 +0000, Daniel P. Berrange wrote:
> > On Sun, Mar 16, 2008 at 05:50:19PM +0100, Daniel Stodden wrote:
> > > On Sun, 2008-03-16 at 15:52 +0100, Pavel Muller wrote:
> > > > Hello,
> > > > I want to ask if XEN use TUP/TAP interfaces or use other interface?
> > > 
> > > No. TUN/TAP is typically used for hosted VMs. Broadly speaking, it's
> > > only useful if a significant part of the VMM is running in user mode on
> > > top of a native Linux, as is the case with VMware Workstation,
> > > VirtualBox, UserModeLinux etc.
> > > 
> > > Xen is a hypervisor, running below all OSes on bare hardware. The
> > > network virtualization is based on a Linux OS (dom0), but the guests
> > > aren't running on top of that, but rather as siblings on a common
> > > virtualization layer.
> > 
> > Whether it is a separate hypervisor / Dom0, or a combined HV+Dom0 is not
> > really relevant to this question. In both cases the driver backends are 
> > in the Linux host OS and not the hypervisor itself.
> 
> Using TUN/TAP is absolutely pointless if the peer is not running in
> userland. Because connecting userspace to a network interface is the
> whole point there. 
> 
> And this is why the VMM type matters to answer the question.

No the distinction here is between kernel space & user space backends, not
between host OS and hypervisor. The hypervisor doesn't get involved in the
driver backends - it is delegated to the host OS to take care of.

Dan.
-- 
|: Red Hat, Engineering, Boston   -o-   http://people.redhat.com/berrange/ :|
|: http://libvirt.org  -o-  http://virt-manager.org  -o-  http://ovirt.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
|: GnuPG: 7D3B9505  -o-  F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel