Re: [PATCH v16 10/14] s390/zcrypt: driver callback to indicate resource in use

[Tony Krowiak]

On 5/19/21 7:58 AM, Julian Wiedmann wrote:
> On 10.05.21 19:44, Tony Krowiak 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
> > busy error.
> >
> > 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@xxxxxxxxxxxxx>
> > Reviewed-by: Harald Freudenberger <freude@xxxxxxxxxxxxx>
> > Reviewed-by: Halil Pasic <pasic@xxxxxxxxxxxxx>
> > ---
> >   drivers/s390/crypto/ap_bus.c | 160 ++++++++++++++++++++++++++++++++---
> >   drivers/s390/crypto/ap_bus.h |   4 +
> >   2 files changed, 154 insertions(+), 10 deletions(-)
> This doesn't touch the zcrypt drivers, so I _think_ the subject should
> rather be "s390/ap: driver callback to indicate resource in use". Harald?
>
> Same for patch 13.

Kind of a nit, but I can make the change.