Re: [PATCH/RFC 7/9] Virtual network guest device driver

Cornelia Huck
2007-05-21T09:27:21Z

On Mon, 21 May 2007 11:07:07 +0200,
Christian Borntraeger <CBORNTRA-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org> wrote:

> > This is quite easy with KVM. I like the approach that vmchannel has
> > taken. A simple PCI device. That gives you a discovery mechanism for
> > shared memory and an interrupt and then you can just implement a ring
> > queue using those mechanisms (along with a PIO port for signaling from
> > the guest to the host). So given that underlying mechanism, the
> > question is how to expose that within the guest kernel/userspace and
> > within the host.
>
> Sorry for answering late, but I dont like PCI as a device bus for all
> platforms. s390 has no PCI and s390 has no PIO. I would prefer a new
> simple hypercall based virtual bus. I dont know much about windows
> driver programming, but I guess it it is not that hard to add a new bus.

Agreed. Moreover, if you have an existing OS running on a non-pci
platform, it will be far more likely that they will be able to write a
driver against a simple hypercall-based bus than to cook up a
full-blown pci interface.