[libvirt PATCH] nodedev: support 'mtty' device for testing

[Michal Prívozník]

On 7/19/22 18:33, Jonathon Jongsma wrote:
> It would be nice to be able to test the mediated device capabilities
> without having physical hardware which supports it. The 'mtty' kernel
> module presents a virtual parent device which is capable of creating
> 'fake' mediated devices, and as such it would be useful for testing.
> 
> However, the 'mtty' device is not part of an existing device subsystem
> (e.g. PCI, etc), so libvirt ignores it and it does not get added to the
> node device list. And because it does not get added to the node device
> list, it cannot be used to create child mdevs using `virsh
> nodedev-create`.
> 
> There is already a node device type capability
> VIR_NODE_DEV_CAP_MDEV_TYPES that indicates whether a device supports
> creating child mediated devices, but libvirt assumes that this is a
> nested capability (in other words, it assumes that the primary
> capability of a device is something like PCI). If we allow this
> MDEV_TYPES capability to be a primary device capability, then we can
> support virtual devices like 'mtty' as a parent for mediated devices.
> 
> See https://bugzilla.redhat.com/show_bug.cgi?id=2107031
> 
> Signed-off-by: Jonathon Jongsma <jjongsma at redhat.com>
> ---
>  src/conf/node_device_conf.c          | 41 +++++++++++++++++++++++++++-
>  src/conf/node_device_conf.h          | 13 +++++++++
>  src/libvirt_private.syms             |  2 ++
>  src/node_device/node_device_driver.c |  5 +++-
>  src/node_device/node_device_udev.c   | 25 +++++++++++++++++
>  src/util/virmdev.c                   | 28 +++++++++++++++++++
>  src/util/virmdev.h                   |  4 +++
>  7 files changed, 116 insertions(+), 2 deletions(-)

Reviewed-by: Michal Privoznik <mprivozn at redhat.com>

Michal