From: Cornelia Huck <cohuck@redhat.com>
To: Tony Krowiak <akrowiak@linux.ibm.com>
Cc: pmorel@linux.ibm.com, borntraeger@de.ibm.com,
alex.williamson@redhat.com, linux-kernel@vger.kernel.org,
linux-s390@vger.kernel.org, kvm@vger.kernel.org,
frankja@linux.ibm.com, pasic@linux.ibm.com, david@redhat.com,
schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com,
freude@linux.ibm.com, mimu@linux.ibm.com
Subject: Re: [PATCH v3 1/9] s390: vfio_ap: link the vfio_ap devices to the vfio_ap bus subsystem
Date: Wed, 20 Feb 2019 10:05:03 +0100 [thread overview]
Message-ID: <20190220100503.4036e8dd.cohuck@redhat.com> (raw)
In-Reply-To: <f95dec76-ba2e-38b2-64f3-9abe4ca6a501@linux.ibm.com>
On Tue, 19 Feb 2019 17:27:05 -0500
Tony Krowiak <akrowiak@linux.ibm.com> wrote:
> On 2/18/19 11:57 AM, Cornelia Huck wrote:
> > On Mon, 18 Feb 2019 11:35:45 -0500
> > Tony Krowiak <akrowiak@linux.ibm.com> wrote:
> >
> >> On 2/18/19 7:01 AM, Cornelia Huck wrote:
> >>> On Fri, 15 Feb 2019 16:59:33 -0500
> >>> Tony Krowiak <akrowiak@linux.ibm.com> wrote:
> >>>
> >>>> On 2/15/19 4:11 AM, Cornelia Huck wrote:
> >>>>> On Thu, 14 Feb 2019 13:30:59 -0500
> >>>>> Tony Krowiak <akrowiak@linux.ibm.com> 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 :(
next prev parent reply other threads:[~2019-02-20 9:05 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-14 13:51 [PATCH v3 0/9] [RFC] vfio: ap: ioctl definitions for AP Queue Interrupt Control Pierre Morel
2019-02-14 13:51 ` [PATCH v3 1/9] s390: vfio_ap: link the vfio_ap devices to the vfio_ap bus subsystem Pierre Morel
2019-02-14 14:54 ` Cornelia Huck
2019-02-14 15:05 ` Christian Borntraeger
2019-02-14 15:40 ` Cornelia Huck
2019-02-14 17:12 ` Tony Krowiak
2019-02-14 17:35 ` Pierre Morel
2019-02-14 15:47 ` Pierre Morel
2019-02-14 16:57 ` Cornelia Huck
2019-02-14 17:36 ` Pierre Morel
2019-02-14 18:30 ` Tony Krowiak
2019-02-15 9:11 ` Cornelia Huck
2019-02-15 21:59 ` Tony Krowiak
2019-02-18 12:01 ` Cornelia Huck
2019-02-18 16:35 ` Tony Krowiak
2019-02-18 16:57 ` Cornelia Huck
2019-02-19 22:27 ` Tony Krowiak
2019-02-20 9:05 ` Cornelia Huck [this message]
2019-02-14 15:01 ` Christian Borntraeger
2019-02-14 15:09 ` Pierre Morel
2019-02-14 13:51 ` [PATCH v3 2/9] s390: ap: kvm: setting a hook for PQAP instructions Pierre Morel
2019-02-14 15:54 ` Cornelia Huck
2019-02-14 16:45 ` Pierre Morel
2019-02-15 9:26 ` Cornelia Huck
2019-02-15 9:55 ` Pierre Morel
2019-02-15 22:02 ` Tony Krowiak
2019-02-18 18:29 ` Pierre Morel
2019-02-18 22:42 ` Cornelia Huck
2019-02-19 19:50 ` Pierre Morel
2019-02-19 22:36 ` Tony Krowiak
2019-02-21 12:40 ` Pierre Morel
2019-02-19 22:50 ` Tony Krowiak
2019-02-14 13:51 ` [PATCH v3 3/9] s390: ap: new vfio_ap_queue structure Pierre Morel
2019-02-15 9:37 ` Cornelia Huck
2019-02-15 9:58 ` Pierre Morel
2019-02-14 13:51 ` [PATCH v3 4/9] s390: ap: tools to find a queue with a specific APQN Pierre Morel
2019-02-15 9:49 ` Cornelia Huck
2019-02-15 10:10 ` Pierre Morel
2019-02-15 10:24 ` Cornelia Huck
2019-02-15 22:13 ` Tony Krowiak
2019-02-18 12:21 ` Cornelia Huck
2019-02-18 18:32 ` Pierre Morel
2019-02-22 15:04 ` Tony Krowiak
2019-02-14 13:51 ` [PATCH v3 5/9] s390: ap: tools to associate a queue to a matrix Pierre Morel
2019-02-15 22:30 ` Tony Krowiak
2019-02-18 18:36 ` Pierre Morel
2019-02-14 13:51 ` [PATCH v3 6/9] vfio: ap: register IOMMU VFIO notifier Pierre Morel
2019-02-15 22:55 ` Tony Krowiak
2019-02-19 9:59 ` Halil Pasic
2019-02-19 19:04 ` Pierre Morel
2019-02-19 21:33 ` Tony Krowiak
2019-02-19 18:51 ` Pierre Morel
2019-02-14 13:51 ` [PATCH v3 7/9] s390: ap: implement PAPQ AQIC interception in kernel Pierre Morel
2019-02-15 23:11 ` Tony Krowiak
2019-02-19 19:16 ` Pierre Morel
2019-02-20 11:54 ` Halil Pasic
2019-02-21 12:50 ` Pierre Morel
2019-02-14 13:51 ` [PATCH v3 8/9] s390: ap: Cleanup on removing the AP device Pierre Morel
2019-02-15 23:29 ` Tony Krowiak
2019-02-19 19:29 ` Pierre Morel
2019-02-15 23:36 ` Tony Krowiak
2019-02-19 19:41 ` Pierre Morel
2019-02-14 13:51 ` [PATCH v3 9/9] s390: ap: kvm: add AP Queue Interruption Control facility Pierre Morel
2019-02-14 20:33 ` [PATCH v3 0/9] [RFC] vfio: ap: ioctl definitions for AP Queue Interrupt Control Tony Krowiak
2019-02-15 8:44 ` Pierre Morel
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