On Tue, 19 Feb 2019 17:27:05 -0500 Tony Krowiak <akrowiak@xxxxxxxxxxxxx> wrote: > On 2/18/19 11:57 AM, Cornelia Huck wrote: > > On Mon, 18 Feb 2019 11:35:45 -0500 > > Tony Krowiak <akrowiak@xxxxxxxxxxxxx> wrote: > > > >> On 2/18/19 7:01 AM, Cornelia Huck wrote: > >>> On Fri, 15 Feb 2019 16:59:33 -0500 > >>> Tony Krowiak <akrowiak@xxxxxxxxxxxxx> wrote: > >>> > >>>> On 2/15/19 4:11 AM, Cornelia Huck wrote: > >>>>> On Thu, 14 Feb 2019 13:30:59 -0500 > >>>>> Tony Krowiak <akrowiak@xxxxxxxxxxxxx> wrote: > >>>>> > >>>>>> On 2/14/19 12:36 PM, Pierre Morel wrote: > >>>>>>> On 14/02/2019 17:57, Cornelia Huck wrote: > >>> > >>>>>>>> (And reading further in the current code, it seems we clear that > >>>>>>>> structure _after_ the matrix device had been setup, so how can that > >>>>>>>> even work? Where am I confused?) > >>>>>>> > >>>>>>> On device_register there were no bus, so the core just do not look for a > >>>>>>> driver and this field was nor tested nor overwritten. > >>>>> > >>>>> Hm... so has the callback in driver_for_each_device() in > >>>>> vfio_ap_verify_queue_reserved() ever been invoked at all? It seems this > >>>>> patch fixes more than just libudev issues... > >>>> > >>>> It is this patch that rendered the driver_for_each_device() in > >>>> vfio_ap_verify_queue_reserved() erroneous. That function gets called > >>>> every time an adapter or domain is assigned to the mdev. This patch > >>>> introduced the problem with driver_for_each_device(). > >>> > >>> So, does this function need to be removed or called from another place, > >>> then? (It looks like it was dead code before.) > >> > >> I don't see why you think it's dead code: > >> > >> assign_adapter_store > >> ==> vfio_ap_mdev_verify_queues_reserved_for_apid > >> ==> vfio_ap_verify_queue_reserved > >> ==> driver_for_each_device > >> > >> The only way that the vfio_ap_verify_queue_reserved - the function that > >> calls driver_for_each_device - does not get called is if no bits have > >> yet been set in matrix_mdev->matrix.aqm. > > > > What I don't see is how this can be called if no device has been, in > > fact, bound to the driver in the driver core... > > Let's start with the fact that one can create an mdev device regardless > of whether a queue has been bound to the vfio_ap driver. Once an mdev > device is created, one can start assigning adapters, domains and control > domains to it. Let's say the admin now attempts to assign an adapter, in > which case the assign_adapter_store() function is invoked. After > verifying that the APID passed in is a valid adapter number, the > vfio_ap_mdev_verify_queues_reserved_for_apid() function is called. > This function first checks if any domains have been assigned and if not, > calls vfio_ap_verify_queue_reserved(&apid, NULL). It is in this function > that the driver_for_each_device() function is called. Since there are > no devices bound to the vfio_ap device driver, the callback passed in to > the driver_for_each_device() function will never get called, so the > vfio_ap_mdev_verify_queues_reserved_for_apid() function will return > -EADDRNOTAVAIL. A similar flow will occur if the first assignment is for > a domain. The bottom line is, the driver_for_each_device() function is > called every time an adapter or domain is assigned. Indeed. I just got lost with the various drivers and devices in play here :(
