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Subject[PATCH v8 08/22] s390: vfio-ap: base implementation of VFIO AP device driver
Date
From: Tony Krowiak <akrowiak@linux.ibm.com>

Introduces a new AP device driver. This device driver
is built on the VFIO mediated device framework. The framework
provides sysfs interfaces that facilitate passthrough
access by guests to devices installed on the linux host.

The VFIO AP device driver will serve two purposes:

1. Provide the interfaces to reserve AP devices for exclusive
use by KVM guests. This is accomplished by unbinding the
devices to be reserved for guest usage from the zcrypt
device driver and binding them to the VFIO AP device driver.

2. Implements the functions, callbacks and sysfs attribute
interfaces required to create one or more VFIO mediated
devices each of which will be used to configure the AP
matrix for a guest and serve as a file descriptor
for facilitating communication between QEMU and the
VFIO AP device driver.

When the VFIO AP device driver is initialized:

* It registers with the AP bus for control of type 10 (CEX4
and newer) AP queue devices. This limitation was imposed
due to:

1. A desire to keep the code as simple as possible;

2. Some older models are no longer supported by the kernel
and others are getting close to end of service.

The probe and remove callbacks will be provided to support
the binding/unbinding of AP queue devices to/from the VFIO
AP device driver.

* Creates a virtual misc device, /sys/devices/virtual/misc/vfio_ap,
device to serve as the parent of the mediated devices created, one
for each guest, and to hold the APQNs of the AP devices bound to
the VFIO AP device driver.

Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Tested-by: Michael Mueller <mimu@linux.ibm.com>
Tested-by: Farhan Ali <alifm@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
MAINTAINERS | 10 +++
arch/s390/Kconfig | 11 +++
drivers/s390/crypto/Makefile | 4 +
drivers/s390/crypto/vfio_ap_drv.c | 115 +++++++++++++++++++++++++++++++++
drivers/s390/crypto/vfio_ap_private.h | 30 +++++++++
5 files changed, 170 insertions(+), 0 deletions(-)
create mode 100644 drivers/s390/crypto/vfio_ap_drv.c
create mode 100644 drivers/s390/crypto/vfio_ap_private.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 7cebd5b..0e0792a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12418,6 +12418,16 @@ W: http://www.ibm.com/developerworks/linux/linux390/
S: Supported
F: drivers/s390/crypto/

+S390 VFIO AP DRIVER
+M: Tony Krowiak <akrowiak@linux.ibm.com>
+M: Pierre Morel <pmorel@linux.ibm.com>
+M: Halil Pasic <pasic@linux.ibm.com>
+L: linux-s390@vger.kernel.org
+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
+
S390 ZFCP DRIVER
M: Steffen Maier <maier@linux.ibm.com>
M: Benjamin Block <bblock@linux.ibm.com>
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 8a1863d..35e9640 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -779,6 +779,17 @@ config VFIO_CCW
To compile this driver as a module, choose M here: the
module will be called vfio_ccw.

+config VFIO_AP
+ def_tristate n
+ prompt "VFIO support for AP devices"
+ depends on ZCRYPT && VFIO_MDEV_DEVICE && KVM
+ help
+ This driver grants access to Adjunct Processor (AP) devices
+ via the VFIO mediated device interface.
+
+ To compile this driver as a module, choose M here: the module
+ will be called vfio_ap.
+
endmenu

menu "Dump support"
diff --git a/drivers/s390/crypto/Makefile b/drivers/s390/crypto/Makefile
index b59af54..48e466e 100644
--- a/drivers/s390/crypto/Makefile
+++ b/drivers/s390/crypto/Makefile
@@ -15,3 +15,7 @@ obj-$(CONFIG_ZCRYPT) += zcrypt_pcixcc.o zcrypt_cex2a.o zcrypt_cex4.o
# pkey kernel module
pkey-objs := pkey_api.o
obj-$(CONFIG_PKEY) += pkey.o
+
+# adjunct processor matrix
+vfio_ap-objs := vfio_ap_drv.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
new file mode 100644
index 0000000..d7e39ad
--- /dev/null
+++ b/drivers/s390/crypto/vfio_ap_drv.c
@@ -0,0 +1,115 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * VFIO based AP device driver
+ *
+ * Copyright IBM Corp. 2018
+ *
+ * Author(s): Tony Krowiak <akrowiak@linux.ibm.com>
+ * Halil Pasic <pasic@linux.ibm.com>
+ */
+
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include "vfio_ap_private.h"
+
+#define VFIO_AP_ROOT_NAME "vfio_ap"
+#define VFIO_AP_DEV_TYPE_NAME "ap_matrix"
+#define VFIO_AP_DEV_NAME "vfio_ap"
+
+MODULE_AUTHOR("IBM Corporation");
+MODULE_DESCRIPTION("VFIO AP device driver, Copyright IBM Corp. 2018");
+MODULE_LICENSE("GPL v2");
+
+static struct ap_driver vfio_ap_drv;
+
+static struct device_type vfio_ap_dev_type = {
+ .name = VFIO_AP_DEV_TYPE_NAME,
+};
+
+struct ap_matrix_dev matrix_dev = {
+ /*
+ * We may add some fops later to implement a more program friendly
+ * management interface for vfio_ap_mdev devices.
+ */
+ .misc_dev = {
+ MISC_DYNAMIC_MINOR,
+ VFIO_AP_DEV_NAME,
+ }
+};
+
+/* Only type 10 adapters (CEX4 and later) are supported
+ * by the AP matrix device driver
+ */
+static struct ap_device_id ap_queue_ids[] = {
+ { .dev_type = AP_DEVICE_TYPE_CEX4,
+ .match_flags = AP_DEVICE_ID_MATCH_QUEUE_TYPE },
+ { .dev_type = AP_DEVICE_TYPE_CEX5,
+ .match_flags = AP_DEVICE_ID_MATCH_QUEUE_TYPE },
+ { .dev_type = AP_DEVICE_TYPE_CEX6,
+ .match_flags = AP_DEVICE_ID_MATCH_QUEUE_TYPE },
+ { /* end of sibling */ },
+};
+
+MODULE_DEVICE_TABLE(vfio_ap, ap_queue_ids);
+
+static int vfio_ap_queue_dev_probe(struct ap_device *apdev)
+{
+ return 0;
+}
+
+static void vfio_ap_queue_dev_remove(struct ap_device *apdev)
+{
+ /* Nothing to do yet */
+}
+
+static int vfio_ap_matrix_dev_create(void)
+{
+ int ret;
+
+ ret = misc_register(&matrix_dev.misc_dev);
+ if (ret)
+ return ret;
+
+ to_device(&matrix_dev)->type = &vfio_ap_dev_type;
+ to_device(&matrix_dev)->driver = &vfio_ap_drv.driver;
+
+ return ret;
+}
+
+static void vfio_ap_matrix_dev_destroy(void)
+{
+ misc_deregister(&matrix_dev.misc_dev);
+}
+
+int __init vfio_ap_init(void)
+{
+ int ret;
+
+ ret = vfio_ap_matrix_dev_create();
+ if (ret)
+ return ret;
+
+ memset(&vfio_ap_drv, 0, sizeof(vfio_ap_drv));
+ vfio_ap_drv.probe = vfio_ap_queue_dev_probe;
+ vfio_ap_drv.remove = vfio_ap_queue_dev_remove;
+ vfio_ap_drv.ids = ap_queue_ids;
+
+ ret = ap_driver_register(&vfio_ap_drv, THIS_MODULE, VFIO_AP_DRV_NAME);
+ if (ret) {
+ vfio_ap_matrix_dev_destroy();
+ return ret;
+ }
+
+ return 0;
+}
+
+void __exit vfio_ap_exit(void)
+{
+ ap_driver_unregister(&vfio_ap_drv);
+ vfio_ap_matrix_dev_destroy();
+}
+
+module_init(vfio_ap_init);
+module_exit(vfio_ap_exit);
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
new file mode 100644
index 0000000..02c878c
--- /dev/null
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Private data and functions for adjunct processor VFIO matrix driver.
+ *
+ * Copyright IBM Corp. 2018
+ */
+
+#ifndef _VFIO_AP_PRIVATE_H_
+#define _VFIO_AP_PRIVATE_H_
+
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+
+#include "ap_bus.h"
+
+#define VFIO_AP_MODULE_NAME "vfio_ap"
+#define VFIO_AP_DRV_NAME "vfio_ap"
+
+struct ap_matrix_dev {
+ struct miscdevice misc_dev;
+};
+
+extern struct ap_matrix_dev matrix_dev;
+
+static inline struct device *to_device(struct ap_matrix_dev *matrix_dev)
+{
+ return matrix_dev->misc_dev.this_device;
+}
+
+#endif /* _VFIO_AP_PRIVATE_H_ */
--
1.7.1
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