Re: [libvirt] [Question] nodedev-list --cap return nothing after creating a mdev

a mdev > > On Thu, Feb 01, 2018 at 09:08:59AM +0000, Wuzongyong (Euler Dept) wrote: > > Hi, > > > > I solve this problem by sending a CHANGE event to userspace after > creating the symbol link like sriov driver. > > > > diff --git a/drivers/vfio/mdev/mdev_core.c > > b/drivers/vfio/mdev/mdev_core.c index 1269910..a23f1d7 100644 > > --- a/drivers/vfio/mdev/mdev_core.c > > +++ b/drivers/vfio/mdev/mdev_core.c > > @@ -351,6 +351,8 @@ int mdev_device_create(struct kobject *kobj, struct > device *dev, uuid_le uuid) > > goto create_failed; > > } > > > > + kobject_uevent(&(mdev->dev.kobj), KOBJ_CHANGE); > > + > > mdev->type_kobj = kobj; > > dev_dbg(&mdev->dev, "MDEV: created\n"); > > > > Is this patch ok? > > I'm not really familiar with kernel, but from a layman's point of view, > the ADD and CHANGE event should be clearly distinguished, but here you > expect the CHANGE event to be the result of creating the sysfs entry, > whereas in general you'd expect this from the ADD event, since it's really > the object has just been created for the first time, right? > > Erik > The ADD event has been sended before sending CHANGE event. And before sending ADD event, the mdev sysfs file node and some general attribute such as power/uevent has been created, but the mdev_type file(link libvirt want to resolve) has not been created yet. So I think maybe we should send a CHANGE event to tell libvirt this link has been created so libvirt can resolve it correctly.