[PATCH 2/3] conf, docs: Add support for dummy network interface

[Daniel P. Berrangé]

On Thu, Aug 04, 2022 at 03:07:17PM +0200, Martin Kletzander wrote:
> Signed-off-by: Martin Kletzander <mkletzan at redhat.com>
> ---
>  docs/formatdomain.rst             | 24 ++++++++++++++++++++++++
>  src/ch/ch_monitor.c               |  1 +
>  src/conf/domain_conf.c            | 10 ++++++++++
>  src/conf/domain_conf.h            |  1 +
>  src/conf/netdev_bandwidth_conf.c  |  1 +
>  src/conf/schemas/domaincommon.rng |  7 +++++++
>  src/libxl/libxl_conf.c            |  1 +
>  src/libxl/xen_common.c            |  1 +
>  src/lxc/lxc_controller.c          |  1 +
>  src/lxc/lxc_driver.c              |  3 +++
>  src/lxc/lxc_process.c             |  4 +++-
>  src/qemu/qemu_command.c           |  4 ++++
>  src/qemu/qemu_domain.c            |  1 +
>  src/qemu/qemu_hotplug.c           |  3 +++
>  src/qemu/qemu_interface.c         |  2 ++
>  src/qemu/qemu_process.c           |  2 ++
>  src/qemu/qemu_validate.c          |  1 +
>  src/vmx/vmx.c                     |  1 +
>  tools/virsh-domain.c              |  1 +
>  19 files changed, 68 insertions(+), 1 deletion(-)
> 
> diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
> index adfdd7b7a5ac..ed0d9c19593b 100644
> --- a/docs/formatdomain.rst
> +++ b/docs/formatdomain.rst
> @@ -5240,6 +5240,30 @@ which the UDP socket packets will originate from the QEMU host. :since:`Since
>     </devices>
>     ...
>  
> +Dummy network interface
> +^^^^^^^^^^^^^^^^^^^^^^^
> +
> +An unconnected network interface sounds pretty pointless, but can show up for
> +example with VMWare when libvirt does not have any more information to provide.
> +Two such scenarios are currently known:
> +
> +1) network interface exists, but is not connected to any existing network
> +2) the interface is connected to something known as VMWare Distributed Switch
> +
> +The difference between these two is not (yet?) discoverable by libvirt, so at
> +least the information gathered from the hypervisor is provided in the
> +element. :since:`Since 8.7.0`
> +
> +::
> +
> +   ...
> +   <devices>
> +     <interface type='dummy'>
> +       <mac address='52:54:00:22:c9:42'/>
> +     </interface>
> +   </devices>
> +   ...

Calling this 'dummy' is not very desirable naming. Especially since
the distributed switch config is handled separately, we're just left
with the case of a network interface without any host backend.

IMHO this should just be type="none", and would likely be viable for
QEMU too.


With regards,
Daniel
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