s390/vfio-ap: use proper locking order when setting/clearing KVM pointer

The group notifier that handles the VFIO_GROUP_NOTIFY_SET_KVM event must
use the required locks in proper locking order to dynamically update the
guest's APCB. The proper locking order is:

       1. matrix_dev->guests_lock: required to use the KVM pointer to
          update a KVM guest's APCB.

       2. matrix_mdev->kvm->lock: required to update a KVM guest's APCB.

       3. matrix_dev->mdevs_lock: required to store or access the data
          stored in a struct ap_matrix_mdev instance.

Two macros are introduced to acquire and release the locks in the proper
order. These macros are now used by the group notifier functions.

Signed-off-by: Tony Krowiak <[email protected]>
Reviewed-by: Jason J. Herne <[email protected]>
Signed-off-by: Alexander Gordeev <[email protected]>

0 files changed, 0 insertions, 0 deletions