[PATCH v17 05/15] s390/vfio-ap: introduce shadow APCB

[Tony Krowiak <akrowiak@xxxxxxxxxxxxx>]

The APCB is a field within the CRYCB that provides the AP configuration
to a KVM guest. Let's introduce a shadow copy of the KVM guest's APCB and
maintain it for the lifespan of the guest.

Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
Reviewed-by: Halil Pasic <pasic@xxxxxxxxxxxxx>
---
 drivers/s390/crypto/vfio_ap_ops.c     | 10 ++++++----
 drivers/s390/crypto/vfio_ap_private.h |  2 ++
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index e2be29e9d310..4305177029bf 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -332,6 +332,7 @@ static int vfio_ap_mdev_probe(struct mdev_device *mdev)
 
 	matrix_mdev->mdev = mdev;
 	vfio_ap_matrix_init(&matrix_dev->info, &matrix_mdev->matrix);
+	vfio_ap_matrix_init(&matrix_dev->info, &matrix_mdev->shadow_apcb);
 	hash_init(matrix_mdev->qtable.queues);
 	mdev_set_drvdata(mdev, matrix_mdev);
 	mutex_lock(&matrix_dev->lock);
@@ -1178,10 +1179,11 @@ static int vfio_ap_mdev_set_kvm(struct ap_matrix_mdev *matrix_mdev,
 		kvm_get_kvm(kvm);
 		matrix_mdev->kvm = kvm;
 		kvm->arch.crypto.data = matrix_mdev;
-		kvm_arch_crypto_set_masks(kvm,
-					  matrix_mdev->matrix.apm,
-					  matrix_mdev->matrix.aqm,
-					  matrix_mdev->matrix.adm);
+		memcpy(&matrix_mdev->shadow_apcb, &matrix_mdev->matrix,
+		       sizeof(struct ap_matrix));
+		kvm_arch_crypto_set_masks(kvm, matrix_mdev->shadow_apcb.apm,
+					  matrix_mdev->shadow_apcb.aqm,
+					  matrix_mdev->shadow_apcb.adm);
 
 		mutex_unlock(&kvm->lock);
 		mutex_unlock(&matrix_dev->lock);
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index c1f57f89973e..6dc0ebbf7a06 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -91,6 +91,7 @@ struct ap_queue_table {
  * @node:	allows the ap_matrix_mdev struct to be added to a list
  * @matrix:	the adapters, usage domains and control domains assigned to the
  *		mediated matrix device.
+ * @shadow_apcb:    the shadow copy of the APCB field of the KVM guest's CRYCB
  * @group_notifier: notifier block used for specifying callback function for
  *		    handling the VFIO_GROUP_NOTIFY_SET_KVM event
  * @iommu_notifier: notifier block used for specifying callback function for
@@ -105,6 +106,7 @@ struct ap_matrix_mdev {
 	struct vfio_device vdev;
 	struct list_head node;
 	struct ap_matrix matrix;
+	struct ap_matrix shadow_apcb;
 	struct notifier_block group_notifier;
 	struct notifier_block iommu_notifier;
 	struct kvm *kvm;
-- 
2.31.1