From: Halil Pasic <pasic@linux.ibm.com>
To: Tony Krowiak <akrowiak@linux.ibm.com>
Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, jjherne@linux.ibm.com, freude@linux.ibm.com,
borntraeger@de.ibm.com, cohuck@redhat.com,
mjrosato@linux.ibm.com, alex.williamson@redhat.com,
kwankhede@nvidia.com, fiuczy@linux.ibm.com,
Halil Pasic <pasic@linux.ibm.com>
Subject: Re: [PATCH v17 14/15] s390/ap: notify drivers on config changed and scan complete callbacks
Date: Tue, 8 Feb 2022 02:38:35 +0100 [thread overview]
Message-ID: <20220208023835.1fc8c6dd.pasic@linux.ibm.com> (raw)
In-Reply-To: <573f8647-7479-3561-cd88-035b4db33e36@linux.ibm.com>
On Mon, 7 Feb 2022 14:39:31 -0500
Tony Krowiak <akrowiak@linux.ibm.com> wrote:
> > Back to the topic of locking: it looks to me that on this path you
> > do the filtering and thus the accesses to matrix_mdev->shadow_apcb,
> > matrix_mdev->matrix and matrix_dev->config_info some of which are
> > of type write whithout the matrix_dev->lock held. More precisely
> > only with the matrix_dev->guests_lock held in "read" mode.
> >
> > Did I misread the code? If not, how is that OK?
>
> You make a valid point, a struct rw_semaphore is not adequate for the
> purposes
> it is used in this patch series. It needs to be a mutex.
>
Good we agree that v17 is racy.
>
> For v18 which is forthcoming probably this week, I've been reworking the
> locking
> based on your observation that the struct ap_guest is not necessary given we
> already have a list of the mediated devices which contain the KVM
> pointer. On the other
[..]
>
> >
> > BTW I got delayed on my "locking rules" writeup. Sorry for that!
>
> No worries, I've been writing up a vfio-ap-locking.rst document to
> include with the next
> version of the patch series.
I'm looking forward to v18 including that document. I prefer not to
discuss what you wrote about the approach taken in v18 now. It is easier
to me when I have both the text stating the intended design, and the
code that is supposed to adhere to this design.
Regards,
Halil
next prev parent reply other threads:[~2022-02-08 1:47 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-21 15:23 [PATCH v17 00/15] s390/vfio-ap: dynamic configuration support Tony Krowiak
2021-10-21 15:23 ` [PATCH v17 01/15] s390/vfio-ap: Set pqap hook when vfio_ap module is loaded Tony Krowiak
2021-12-27 8:21 ` Halil Pasic
2022-01-11 21:13 ` Tony Krowiak
2022-01-04 16:22 ` Jason J. Herne
2022-01-11 17:29 ` Tony Krowiak
2021-10-21 15:23 ` [PATCH v17 02/15] s390/vfio-ap: use new AP bus interface to search for queue devices Tony Krowiak
2021-12-27 8:25 ` Halil Pasic
2022-01-11 17:32 ` Tony Krowiak
2021-10-21 15:23 ` [PATCH v17 03/15] s390/vfio-ap: move probe and remove callbacks to vfio_ap_ops.c Tony Krowiak
2021-10-21 15:23 ` [PATCH v17 04/15] s390/vfio-ap: manage link between queue struct and matrix mdev Tony Krowiak
2021-10-21 15:23 ` [PATCH v17 05/15] s390/vfio-ap: introduce shadow APCB Tony Krowiak
2021-10-21 15:23 ` [PATCH v17 06/15] s390/vfio-ap: refresh guest's APCB by filtering APQNs assigned to mdev Tony Krowiak
2021-12-27 8:53 ` Halil Pasic
2022-01-11 21:19 ` Tony Krowiak
2022-01-12 11:52 ` Halil Pasic
2022-01-15 0:31 ` Tony Krowiak
2021-10-21 15:23 ` [PATCH v17 07/15] s390/vfio-ap: allow assignment of unavailable AP queues to mdev device Tony Krowiak
2021-12-27 9:06 ` Halil Pasic
2021-10-21 15:23 ` [PATCH v17 08/15] s390/vfio-ap: keep track of active guests Tony Krowiak
2021-12-30 2:04 ` Halil Pasic
2022-01-11 21:27 ` Tony Krowiak
2021-12-30 3:33 ` Halil Pasic
2022-01-11 21:58 ` Tony Krowiak
2022-01-11 22:19 ` Tony Krowiak
2022-01-12 14:25 ` Halil Pasic
2022-01-15 0:29 ` Tony Krowiak
2021-10-21 15:23 ` [PATCH v17 09/15] s390/vfio-ap: allow hot plug/unplug of AP resources using mdev device Tony Krowiak
2022-01-09 21:36 ` Halil Pasic
2022-01-11 22:42 ` Tony Krowiak
2021-10-21 15:23 ` [PATCH v17 10/15] s390/vfio-ap: reset queues after adapter/domain unassignment Tony Krowiak
2021-10-21 15:23 ` [PATCH v17 11/15] s390/ap: driver callback to indicate resource in use Tony Krowiak
2021-11-04 11:27 ` Harald Freudenberger
2021-11-04 15:48 ` Tony Krowiak
2021-10-21 15:23 ` [PATCH v17 12/15] s390/vfio-ap: implement in-use callback for vfio_ap driver Tony Krowiak
2021-10-21 15:23 ` [PATCH v17 13/15] s390/vfio-ap: sysfs attribute to display the guest's matrix Tony Krowiak
2021-10-21 15:23 ` [PATCH v17 14/15] s390/ap: notify drivers on config changed and scan complete callbacks Tony Krowiak
2021-11-04 12:06 ` Harald Freudenberger
2021-11-04 15:50 ` Tony Krowiak
2021-11-05 8:23 ` Harald Freudenberger
2021-11-05 13:15 ` Harald Freudenberger
2021-11-08 14:27 ` Tony Krowiak
2021-11-08 14:26 ` Tony Krowiak
2022-02-04 10:43 ` Halil Pasic
2022-02-07 19:39 ` Tony Krowiak
2022-02-08 1:38 ` Halil Pasic [this message]
2022-02-08 3:27 ` Tony Krowiak
2021-10-21 15:23 ` [PATCH v17 15/15] s390/vfio-ap: update docs to include dynamic config support Tony Krowiak
2021-10-27 14:24 ` [PATCH v17 00/15] s390/vfio-ap: dynamic configuration support Tony Krowiak
2021-11-02 19:23 ` Tony Krowiak
2021-11-15 15:45 ` Tony Krowiak
2021-11-22 16:12 ` Tony Krowiak
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