[PATCH v7 05/15] s390/vfio-ap: introduce shadow CRYCB

[Tony Krowiak]

Let's introduce a shadow copy of the KVM guest's CRYCB and maintain it for
the lifespan of the guest. The shadow CRYCB will be used to provide the
AP configuration for a KVM guest.

Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
---
 drivers/s390/crypto/vfio_ap_ops.c     | 31 +++++++++++++++++++++------
 drivers/s390/crypto/vfio_ap_private.h |  1 +
 2 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 8ece0d52ff4c..b8b678032ab7 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -280,14 +280,32 @@ static int handle_pqap(struct kvm_vcpu *vcpu)
 	return 0;
 }
 
+static void vfio_ap_matrix_clear(struct ap_matrix *matrix)
+{
+	bitmap_clear(matrix->apm, 0, AP_DEVICES);
+	bitmap_clear(matrix->aqm, 0, AP_DOMAINS);
+	bitmap_clear(matrix->adm, 0, AP_DOMAINS);
+}
+
 static void vfio_ap_matrix_init(struct ap_config_info *info,
 				struct ap_matrix *matrix)
 {
+	vfio_ap_matrix_clear(matrix);
 	matrix->apm_max = info->apxa ? info->Na : 63;
 	matrix->aqm_max = info->apxa ? info->Nd : 15;
 	matrix->adm_max = info->apxa ? info->Nd : 15;
 }
 
+static bool vfio_ap_mdev_commit_crycb(struct ap_matrix_mdev *matrix_mdev)
+{
+	if (matrix_mdev->kvm && matrix_mdev->kvm->arch.crypto.crycbd) {
+		kvm_arch_crypto_set_masks(matrix_mdev->kvm,
+					  matrix_mdev->shadow_crycb.apm,
+					  matrix_mdev->shadow_crycb.aqm,
+					  matrix_mdev->shadow_crycb.adm);
+	}
+}
+
 static int vfio_ap_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
 {
 	struct ap_matrix_mdev *matrix_mdev;
@@ -303,6 +321,7 @@ static int vfio_ap_mdev_create(struct kobject *kobj, 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_crycb);
 	mdev_set_drvdata(mdev, matrix_mdev);
 	matrix_mdev->pqap_hook.hook = handle_pqap;
 	matrix_mdev->pqap_hook.owner = THIS_MODULE;
@@ -1126,13 +1145,9 @@ static int vfio_ap_mdev_group_notifier(struct notifier_block *nb,
 	if (ret)
 		return NOTIFY_DONE;
 
-	/* If there is no CRYCB pointer, then we can't copy the masks */
-	if (!matrix_mdev->kvm->arch.crypto.crycbd)
-		return NOTIFY_DONE;
-
-	kvm_arch_crypto_set_masks(matrix_mdev->kvm, matrix_mdev->matrix.apm,
-				  matrix_mdev->matrix.aqm,
-				  matrix_mdev->matrix.adm);
+	memcpy(&matrix_mdev->shadow_crycb, &matrix_mdev->matrix,
+	       sizeof(matrix_mdev->shadow_crycb));
+	vfio_ap_mdev_commit_crycb(matrix_mdev);
 
 	return NOTIFY_OK;
 }
@@ -1247,6 +1262,8 @@ static void vfio_ap_mdev_release(struct mdev_device *mdev)
 		kvm_put_kvm(matrix_mdev->kvm);
 		matrix_mdev->kvm = NULL;
 	}
+
+	vfio_ap_matrix_clear(&matrix_mdev->shadow_crycb);
 	mutex_unlock(&matrix_dev->lock);
 
 	vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index 4b6e144bab17..87cc270c3212 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -83,6 +83,7 @@ struct ap_matrix {
 struct ap_matrix_mdev {
 	struct list_head node;
 	struct ap_matrix matrix;
+	struct ap_matrix shadow_crycb;
 	struct notifier_block group_notifier;
 	struct notifier_block iommu_notifier;
 	struct kvm *kvm;
-- 
2.21.1