diff --git a/MAINTAINERS b/MAINTAINERS
index 45cd096c0600..5db5b7e49d08 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12677,6 +12677,7 @@ W:	http://www.ibm.com/developerworks/linux/linux390/
 S:	Supported
 F:	drivers/s390/crypto/vfio_ap_drv.c
 F:	drivers/s390/crypto/vfio_ap_private.h
+F:	drivers/s390/crypto/vfio_ap_ops.c
 
 S390 ZFCP DRIVER
 M:	Steffen Maier <maier@linux.ibm.com>
diff --git a/drivers/s390/crypto/Makefile b/drivers/s390/crypto/Makefile
index 48e466eb19cf..8d36b05a7575 100644
--- a/drivers/s390/crypto/Makefile
+++ b/drivers/s390/crypto/Makefile
@@ -17,5 +17,5 @@ pkey-objs := pkey_api.o
 obj-$(CONFIG_PKEY) += pkey.o
 
 # adjunct processor matrix
-vfio_ap-objs := vfio_ap_drv.o
+vfio_ap-objs := vfio_ap_drv.o vfio_ap_ops.o
 obj-$(CONFIG_VFIO_AP) += vfio_ap.o
diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
index ea2ae03c896e..8b51821d9bf7 100644
--- a/drivers/s390/crypto/vfio_ap_drv.c
+++ b/drivers/s390/crypto/vfio_ap_drv.c
@@ -76,6 +76,16 @@ static int vfio_ap_matrix_dev_create(void)
 		goto matrix_alloc_err;
 	}
 
+	/* Fill in config info via PQAP(QCI), if available */
+	if (test_facility(12)) {
+		ret = ap_qci(&matrix_dev->info);
+		if (ret)
+			goto matrix_alloc_err;
+	}
+
+	mutex_init(&matrix_dev->lock);
+	INIT_LIST_HEAD(&matrix_dev->mdev_list);
+
 	matrix_dev->device.type = &vfio_ap_dev_type;
 	dev_set_name(&matrix_dev->device, "%s", VFIO_AP_DEV_NAME);
 	matrix_dev->device.parent = root_device;
@@ -125,11 +135,20 @@ int __init vfio_ap_init(void)
 		return ret;
 	}
 
+	ret = vfio_ap_mdev_register();
+	if (ret) {
+		ap_driver_unregister(&vfio_ap_drv);
+		vfio_ap_matrix_dev_destroy();
+
+		return ret;
+	}
+
 	return 0;
 }
 
 void __exit vfio_ap_exit(void)
 {
+	vfio_ap_mdev_unregister();
 	ap_driver_unregister(&vfio_ap_drv);
 	vfio_ap_matrix_dev_destroy();
 }
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
new file mode 100644
index 000000000000..99ed30315f56
--- /dev/null
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Adjunct processor matrix VFIO device driver callbacks.
+ *
+ * Copyright IBM Corp. 2018
+ *
+ * Author(s): Tony Krowiak <akrowiak@linux.ibm.com>
+ *	      Halil Pasic <pasic@linux.ibm.com>
+ *	      Pierre Morel <pmorel@linux.ibm.com>
+ */
+#include <linux/string.h>
+#include <linux/vfio.h>
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/ctype.h>
+#include <asm/zcrypt.h>
+
+#include "vfio_ap_private.h"
+
+#define VFIO_AP_MDEV_TYPE_HWVIRT "passthrough"
+#define VFIO_AP_MDEV_NAME_HWVIRT "VFIO AP Passthrough Device"
+
+static void vfio_ap_matrix_init(struct ap_config_info *info,
+				struct ap_matrix *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 int vfio_ap_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
+{
+	struct ap_matrix_mdev *matrix_mdev;
+
+	if ((atomic_dec_if_positive(&matrix_dev->available_instances) < 0))
+		return -EPERM;
+
+	matrix_mdev = kzalloc(sizeof(*matrix_mdev), GFP_KERNEL);
+	if (!matrix_mdev) {
+		atomic_inc(&matrix_dev->available_instances);
+		return -ENOMEM;
+	}
+
+	vfio_ap_matrix_init(&matrix_dev->info, &matrix_mdev->matrix);
+	mdev_set_drvdata(mdev, matrix_mdev);
+	mutex_lock(&matrix_dev->lock);
+	list_add(&matrix_mdev->node, &matrix_dev->mdev_list);
+	mutex_unlock(&matrix_dev->lock);
+
+	return 0;
+}
+
+static int vfio_ap_mdev_remove(struct mdev_device *mdev)
+{
+	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+
+	mutex_lock(&matrix_dev->lock);
+	list_del(&matrix_mdev->node);
+	mutex_unlock(&matrix_dev->lock);
+
+	kfree(matrix_mdev);
+	mdev_set_drvdata(mdev, NULL);
+	atomic_inc(&matrix_dev->available_instances);
+
+	return 0;
+}
+
+static ssize_t name_show(struct kobject *kobj, struct device *dev, char *buf)
+{
+	return sprintf(buf, "%s\n", VFIO_AP_MDEV_NAME_HWVIRT);
+}
+
+MDEV_TYPE_ATTR_RO(name);
+
+static ssize_t available_instances_show(struct kobject *kobj,
+					struct device *dev, char *buf)
+{
+	return sprintf(buf, "%d\n",
+		       atomic_read(&matrix_dev->available_instances));
+}
+
+MDEV_TYPE_ATTR_RO(available_instances);
+
+static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
+			       char *buf)
+{
+	return sprintf(buf, "%s\n", VFIO_DEVICE_API_AP_STRING);
+}
+
+MDEV_TYPE_ATTR_RO(device_api);
+
+static struct attribute *vfio_ap_mdev_type_attrs[] = {
+	&mdev_type_attr_name.attr,
+	&mdev_type_attr_device_api.attr,
+	&mdev_type_attr_available_instances.attr,
+	NULL,
+};
+
+static struct attribute_group vfio_ap_mdev_hwvirt_type_group = {
+	.name = VFIO_AP_MDEV_TYPE_HWVIRT,
+	.attrs = vfio_ap_mdev_type_attrs,
+};
+
+static struct attribute_group *vfio_ap_mdev_type_groups[] = {
+	&vfio_ap_mdev_hwvirt_type_group,
+	NULL,
+};
+
+static const struct mdev_parent_ops vfio_ap_matrix_ops = {
+	.owner			= THIS_MODULE,
+	.supported_type_groups	= vfio_ap_mdev_type_groups,
+	.create			= vfio_ap_mdev_create,
+	.remove			= vfio_ap_mdev_remove,
+};
+
+int vfio_ap_mdev_register(void)
+{
+	atomic_set(&matrix_dev->available_instances, MAX_ZDEV_ENTRIES_EXT);
+
+	return mdev_register_device(&matrix_dev->device, &vfio_ap_matrix_ops);
+}
+
+void vfio_ap_mdev_unregister(void)
+{
+	mdev_unregister_device(&matrix_dev->device);
+}
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index 6141420c8bb0..9f197ffab7ad 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -3,6 +3,7 @@
  * Private data and functions for adjunct processor VFIO matrix driver.
  *
  * Author(s): Tony Krowiak <akrowiak@linux.ibm.com>
+ *	      Halil Pasic <pasic@linux.ibm.com>
  *
  * Copyright IBM Corp. 2018
  */
@@ -24,11 +25,59 @@
 /**
  * ap_matrix_dev - the AP matrix device structure
  * @device:	generic device structure associated with the AP matrix device
+ * @available_instances: number of mediated matrix devices that can be created
+ * @info:	the struct containing the output from the PQAP(QCI) instruction
+ * mdev_list:	the list of mediated matrix devices created
+ * lock:	mutex for locking the AP matrix device. This lock will be
+ *		taken every time we fiddle with state managed by the vfio_ap
+ *		driver, be it using @mdev_list or writing the state of a
+ *		single ap_matrix_mdev device. It's quite coarse but we don't
+ *		expect much contention.
  */
 struct ap_matrix_dev {
 	struct device device;
+	atomic_t available_instances;
+	struct ap_config_info info;
+	struct list_head mdev_list;
+	struct mutex lock;
 };
 
 extern struct ap_matrix_dev *matrix_dev;
 
+/**
+ * The AP matrix is comprised of three bit masks identifying the adapters,
+ * queues (domains) and control domains that belong to an AP matrix. The bits i
+ * each mask, from least significant to most significant bit, correspond to IDs
+ * 0 to 255. When a bit is set, the corresponding ID belongs to the matrix.
+ *
+ * @apm_max: max adapter number in @apm
+ * @apm identifies the AP adapters in the matrix
+ * @aqm_max: max domain number in @aqm
+ * @aqm identifies the AP queues (domains) in the matrix
+ * @adm_max: max domain number in @adm
+ * @adm identifies the AP control domains in the matrix
+ */
+struct ap_matrix {
+	unsigned long apm_max;
+	DECLARE_BITMAP(apm, 256);
+	unsigned long aqm_max;
+	DECLARE_BITMAP(aqm, 256);
+	unsigned long adm_max;
+	DECLARE_BITMAP(adm, 256);
+};
+
+/**
+ * struct ap_matrix_mdev - the mediated matrix device structure
+ * @list:	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.
+ */
+struct ap_matrix_mdev {
+	struct list_head node;
+	struct ap_matrix matrix;
+};
+
+extern int vfio_ap_mdev_register(void);
+extern void vfio_ap_mdev_unregister(void);
+
 #endif /* _VFIO_AP_PRIVATE_H_ */
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 1aa7b82e8169..bfbe2be8f369 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -215,6 +215,7 @@ struct vfio_device_info {
 #define VFIO_DEVICE_API_PLATFORM_STRING		"vfio-platform"
 #define VFIO_DEVICE_API_AMBA_STRING		"vfio-amba"
 #define VFIO_DEVICE_API_CCW_STRING		"vfio-ccw"
+#define VFIO_DEVICE_API_AP_STRING		"vfio-ap"
 
 /**
  * VFIO_DEVICE_GET_REGION_INFO - _IOWR(VFIO_TYPE, VFIO_BASE + 8,
