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, 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,
frankja@linux.ibm.com, david@redhat.com, hca@linux.ibm.com,
gor@linux.ibm.com
Subject: Re: [PATCH v11 04/14] s390/zcrypt: driver callback to indicate resource in use
Date: Tue, 27 Oct 2020 14:01:57 +0100 [thread overview]
Message-ID: <20201027140157.0b510450.pasic@linux.ibm.com> (raw)
In-Reply-To: <20201022171209.19494-5-akrowiak@linux.ibm.com>
On Thu, 22 Oct 2020 13:11:59 -0400
Tony Krowiak <akrowiak@linux.ibm.com> wrote:
> Introduces a new driver callback to prevent a root user from unbinding
> an AP queue from its device driver if the queue is in use. The callback
> will be invoked whenever a change to the AP bus's sysfs apmask or aqmask
> attributes would result in one or more AP queues being removed from its
> driver. If the callback responds in the affirmative for any driver
> queried, the change to the apmask or aqmask will be rejected with a device
> in use error.
Like discussed last time, there seems to be nothing, that would prevent
a resource becoming in use between the in_use() callback returned false
and the resource being removed as a result of ap_bus_revise_bindings().
Another thing that may be of interest, is that now we hold the
ap_perms_mutex for the in_use() checks. The ap_perms_mutex is used
in ap_device_probe() and I don't quite understand some
usages of in zcrypt_api.c My feeling is that the extra pressure on that
lock should not be a problem, except if in_use() were to not return
because of some deadlock.
With all that said if Harald is fine with it, so am I.
Acked-by: Halil Pasic <pasic@linux.ibm.com>
>
> For this patch, only non-default drivers will be queried. Currently,
> there is only one non-default driver, the vfio_ap device driver. The
> vfio_ap device driver facilitates pass-through of an AP queue to a
> guest. The idea here is that a guest may be administered by a different
> sysadmin than the host and we don't want AP resources to unexpectedly
> disappear from a guest's AP configuration (i.e., adapters and domains
> assigned to the matrix mdev). This will enforce the proper procedure for
> removing AP resources intended for guest usage which is to
> first unassign them from the matrix mdev, then unbind them from the
> vfio_ap device driver.
>
> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
>
next prev parent reply other threads:[~2020-10-27 13:02 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-22 17:11 [PATCH v11 00/14] s390/vfio-ap: dynamic configuration support Tony Krowiak
2020-10-22 17:11 ` [PATCH v11 01/14] s390/vfio-ap: No need to disable IRQ after queue reset Tony Krowiak
2020-10-22 19:44 ` kernel test robot
2020-10-26 16:57 ` Tony Krowiak
2020-10-27 6:48 ` Halil Pasic
2020-10-29 23:29 ` Tony Krowiak
2020-10-30 16:13 ` Tony Krowiak
2020-10-30 17:27 ` Halil Pasic
2020-10-30 20:45 ` Tony Krowiak
2020-10-30 17:42 ` Halil Pasic
2020-10-30 20:37 ` Tony Krowiak
2020-10-31 3:43 ` Halil Pasic
2020-11-02 14:35 ` Tony Krowiak
2020-10-30 17:54 ` Halil Pasic
2020-10-30 20:53 ` Tony Krowiak
2020-10-30 21:13 ` Tony Krowiak
2020-10-30 17:56 ` Halil Pasic
2020-10-30 21:17 ` Tony Krowiak
2020-10-22 17:11 ` [PATCH v11 02/14] 390/vfio-ap: use new AP bus interface to search for queue devices Tony Krowiak
2020-10-27 7:01 ` Halil Pasic
2020-11-02 21:57 ` Tony Krowiak
2020-10-22 17:11 ` [PATCH v11 03/14] s390/vfio-ap: manage link between queue struct and matrix mdev Tony Krowiak
2020-10-27 9:33 ` Halil Pasic
2020-10-22 17:11 ` [PATCH v11 04/14] s390/zcrypt: driver callback to indicate resource in use Tony Krowiak
2020-10-27 13:01 ` Halil Pasic [this message]
2020-10-27 16:55 ` Harald Freudenberger
2020-11-13 21:30 ` Tony Krowiak
2020-11-14 0:00 ` Halil Pasic
2020-11-16 16:23 ` Tony Krowiak
2020-10-22 17:12 ` [PATCH v11 05/14] s390/vfio-ap: implement in-use callback for vfio_ap driver Tony Krowiak
2020-10-27 13:27 ` Halil Pasic
2020-11-13 17:14 ` Tony Krowiak
2020-11-13 23:47 ` Halil Pasic
2020-11-16 16:58 ` Tony Krowiak
2020-11-23 17:03 ` Cornelia Huck
2020-11-23 19:23 ` Tony Krowiak
2020-10-22 17:12 ` [PATCH v11 06/14] s390/vfio-ap: introduce shadow APCB Tony Krowiak
2020-10-28 8:11 ` Halil Pasic
2020-11-13 17:18 ` Tony Krowiak
2020-10-22 17:12 ` [PATCH v11 07/14] s390/vfio-ap: sysfs attribute to display the guest's matrix Tony Krowiak
2020-10-28 8:17 ` Halil Pasic
2020-11-13 17:27 ` Tony Krowiak
2020-11-13 23:12 ` Halil Pasic
2020-11-19 18:15 ` Tony Krowiak
2020-10-22 17:12 ` [PATCH v11 08/14] s390/vfio-ap: hot plug/unplug queues on bind/unbind of queue device Tony Krowiak
2020-10-22 20:30 ` kernel test robot
2020-10-26 17:04 ` Tony Krowiak
2020-10-28 13:57 ` Halil Pasic
2020-11-03 22:49 ` Tony Krowiak
2020-11-04 12:52 ` Halil Pasic
2020-11-04 21:20 ` Tony Krowiak
2020-11-05 12:27 ` Halil Pasic
2020-11-13 20:36 ` Tony Krowiak
2020-11-04 13:23 ` Halil Pasic
2020-10-22 17:12 ` [PATCH v11 09/14] s390/vfio-ap: allow assignment of unavailable AP queues to mdev device Tony Krowiak
2020-10-28 15:03 ` Halil Pasic
2020-10-22 17:12 ` [PATCH v11 10/14] s390/vfio-ap: allow hot plug/unplug of AP resources using " Tony Krowiak
2020-10-22 17:12 ` [PATCH v11 11/14] s390/zcrypt: Notify driver on config changed and scan complete callbacks Tony Krowiak
2020-10-27 17:28 ` Harald Freudenberger
2020-11-13 20:58 ` Tony Krowiak
2020-10-22 17:12 ` [PATCH v11 12/14] s390/vfio-ap: handle host AP config change notification Tony Krowiak
2020-10-22 21:17 ` kernel test robot
2020-10-26 17:07 ` Tony Krowiak
2020-10-26 17:21 ` Tony Krowiak
2020-11-03 9:48 ` kernel test robot
2020-11-13 21:06 ` Tony Krowiak
2020-10-22 17:12 ` [PATCH v11 13/14] s390/vfio-ap: handle AP bus scan completed notification Tony Krowiak
2020-10-22 17:12 ` [PATCH v11 14/14] s390/vfio-ap: update docs to include dynamic config support Tony Krowiak
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