[libvirt] [PATCH 5/5] conf: Introduce new video type 'none'

[Erik Skultety]

On Mon, Jul 02, 2018 at 03:48:10PM -0400, John Ferlan wrote:
>
>
> On 06/28/2018 08:15 AM, Erik Skultety wrote:
> > Historically, we've always enabled an emulated video device every time we
> > see that graphics should be supported with a guest. With the appearance
> > of mediated devices which can support QEMU's vfio-display capability,
> > users might want to use such a device as the only video device.
> > Therefore introduce a new, effectively a 'disable', type for video
> > device.
> >
> > Signed-off-by: Erik Skultety <eskultet at redhat.com>
> > ---
> >  docs/formatdomain.html.in                          | 10 +++-
> >  docs/schemas/domaincommon.rng                      |  1 +
> >  src/conf/domain_conf.c                             | 55 ++++++++++++++++------
> >  src/conf/domain_conf.h                             |  1 +
> >  src/qemu/qemu_command.c                            | 13 +++--
> >  src/qemu/qemu_domain.c                             |  3 ++
> >  src/qemu/qemu_domain_address.c                     | 10 ++++
> >  tests/domaincapsschemadata/full.xml                |  1 +
> >  .../video-invalid-multiple-devices.xml             | 33 +++++++++++++
> >  tests/qemuxml2argvdata/video-none-device.args      | 27 +++++++++++
> >  tests/qemuxml2argvdata/video-none-device.xml       | 39 +++++++++++++++
> >  tests/qemuxml2argvtest.c                           |  4 +-
> >  tests/qemuxml2xmloutdata/video-none-device.xml     | 42 +++++++++++++++++
> >  tests/qemuxml2xmltest.c                            |  1 +
> >  14 files changed, 219 insertions(+), 21 deletions(-)
> >  create mode 100644 tests/qemuxml2argvdata/video-invalid-multiple-devices.xml
> >  create mode 100644 tests/qemuxml2argvdata/video-none-device.args
> >  create mode 100644 tests/qemuxml2argvdata/video-none-device.xml
> >  create mode 100644 tests/qemuxml2xmloutdata/video-none-device.xml
> >
>
> I assume this has to do with the egl-headless discussion from the other
> series, so rather than "none", why not go with headless?  The problem I
> see w/ NONE is it's usage/meaning typically as, well, NONE or not
> defined; whereas, for graphics it would then mean, well it's defined,
> but it's something else.

Well, to me, 'headless' would mean that a I could see a video device on the PCI
bus in the guest handled by some kind of 'headless'-relared driver. The point
here is that there must not be any additional device within the guest. The
problem is (I know you're familiar with this, it's just to recap this for other
readers) that we add a default video device when there's a graphics element but
no video in the XML. Having a type 'none' translating into a "no device" was
the best I could come up with that would match the reality.

>
> If this isn't a headless device, then I'll need to revisit my comments
> below...
>
> Also please split domain/docs/xml2ml from qemu/xml2argv

I'll incorporate the rest of the suggestions you had and resend (I'll merge the
rest).

Erik