Re: [Qemu-devel] bidirectional data exchange between guest and host without network

["Richard W.M. Jones" <rjones@redhat.com>]

On Sat, Jul 11, 2009 at 01:04:00AM +0100, Jamie Lokier wrote:
> Anthony Lannuzel wrote:
> > > Can you not create _another_ network device and use that?
> > > QEMU lets you create lots of network devices.
> >
> > No, I do not want the guest to be able to communicate with the host
> > network, so that is not an option.
> 
> So create a network device that is only used for the private
> communication, and isolate from the rest of the host network with
> firewall rules.
> 
> I'll admit that can be a lot of work, if the host has a complex
> network, or a dynamic one where IP addresses are unpredictable.

This is precisely the reason why vmchannel is a good thing.

There is no IPv4 address you can give to the new interface which won't
have the potential to conflict with some other IPv4 address already in
use.  Extra network devices require special handling in firewall rules
and changes to the configuration of every network daemon in the
system.

If you don't add an extra network device to the guest, then you rely
on the host and guest being on the same network, which is not always
true.

While it's possible to configure the guest specially to avoid this,
that doesn't look much like our promise to run any vanilla guest as a
virtual machine.

Rich.

-- 
Richard Jones, Emerging Technologies, Red Hat  http://et.redhat.com/~rjones
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