[RFC 04/19] s390/zcrypt: create an AP matrix device on the AP matrix bus

[Tony Krowiak]

Creates a single AP matrix device on the AP matrix bus.
The matrix device will be created as part of the AP matrix bus
initialization. The matrix device will hold the AP queues that
have been reserved for use by KVM guests. Mediated matrix devices
can then be created for each guest. The mediated matrix devices can
then be configured with a matrix of AP adapters, usage and
control domains that will be made accessible to the guest.

The sysfs location of the matrix device is:

/sys/bus/ap_matrix
... [devices]
...... [matrix]

Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxxxxxxx>
---
 drivers/s390/crypto/ap_matrix_bus.c |   54 +++++++++++++++++++++++++++++++++++
 drivers/s390/crypto/ap_matrix_bus.h |    6 ++++
 2 files changed, 60 insertions(+), 0 deletions(-)

diff --git a/drivers/s390/crypto/ap_matrix_bus.c b/drivers/s390/crypto/ap_matrix_bus.c
index fbae175..4eb1e3c 100644
--- a/drivers/s390/crypto/ap_matrix_bus.c
+++ b/drivers/s390/crypto/ap_matrix_bus.c
@@ -12,6 +12,7 @@
 
 #include <linux/module.h>
 #include <linux/device.h>
+#include <linux/slab.h>
 #include <asm/ap.h>
 
 #include "ap_matrix_bus.h"
@@ -21,13 +22,59 @@
 MODULE_LICENSE("GPL v2");
 
 #define AP_MATRIX_BUS_NAME "ap_matrix"
+#define AP_MATRIX_DEV_TYPE_NAME "ap_matrix"
+#define AP_MATRIX_DEV_NAME "matrix"
 
 static struct device *ap_matrix_root_device;
+static struct ap_matrix *matrix;
 
 static struct bus_type ap_matrix_bus_type = {
 	.name = AP_MATRIX_BUS_NAME,
 };
 
+static struct device_type ap_matrix_type = {
+	.name = AP_MATRIX_DEV_TYPE_NAME,
+};
+
+static void ap_matrix_dev_release(struct device *dev)
+{
+	struct ap_matrix *ap_matrix;
+
+	ap_matrix = container_of(dev, struct ap_matrix, device);
+
+	if (matrix == ap_matrix)
+		kfree(matrix);
+
+	matrix = NULL;
+}
+
+static int ap_matrix_dev_create(void)
+{
+	int ret;
+
+	matrix = kzalloc(sizeof(*matrix), GFP_KERNEL);
+	if (!matrix)
+		return -ENOMEM;
+
+	matrix->device.type = &ap_matrix_type;
+	dev_set_name(&matrix->device, "%s", AP_MATRIX_DEV_NAME);
+	matrix->device.bus = &ap_matrix_bus_type;
+	matrix->device.parent = ap_matrix_root_device;
+	matrix->device.release = ap_matrix_dev_release;
+
+	ret = device_register(&matrix->device);
+	if (ret) {
+		put_device(&matrix->device);
+		kfree(matrix);
+		matrix = NULL;
+		return ret;
+	}
+
+	get_device(&matrix->device);
+
+	return 0;
+}
+
 int __init ap_matrix_init(void)
 {
 	int ret;
@@ -41,8 +88,15 @@ int __init ap_matrix_init(void)
 	if (ret)
 		goto bus_reg_err;
 
+	ret = ap_matrix_dev_create();
+	if (ret)
+		goto matrix_create_err;
+
 	return 0;
 
+matrix_create_err:
+	bus_unregister(&ap_matrix_bus_type);
+
 bus_reg_err:
 	root_device_unregister(ap_matrix_root_device);
 
diff --git a/drivers/s390/crypto/ap_matrix_bus.h b/drivers/s390/crypto/ap_matrix_bus.h
index 58e116f..225db4f 100644
--- a/drivers/s390/crypto/ap_matrix_bus.h
+++ b/drivers/s390/crypto/ap_matrix_bus.h
@@ -10,6 +10,12 @@
 #ifndef _AP_MATRIX_BUS_H_
 #define _AP_MATRIX_BUS_H_
 
+#include <linux/device.h>
+
+struct ap_matrix {
+	struct device device;
+};
+
 int ap_matrix_init(void);
 
 #endif /* _AP_MATRIX_BUS_H_ */
-- 
1.7.1