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@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@redhat.com> Michal