Re: [PATCH v9 09/22] s390: vfio-ap: register matrix device with VFIO mdev framework
From: Tony Krowiak
Date: Wed Aug 15 2018 - 12:52:05 EST
On 08/14/2018 07:19 AM, Cornelia Huck wrote:
On Mon, 13 Aug 2018 17:48:06 -0400
Tony Krowiak <akrowiak@xxxxxxxxxxxxxxxxxx> wrote:
From: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
Registers the matrix device created by the VFIO AP device
driver with the VFIO mediated device framework.
Registering the matrix device will create the sysfs
structures needed to create mediated matrix devices
each of which will be used to configure the AP matrix
for a guest and connect it to the VFIO AP device driver.
Registering the matrix device with the VFIO mediated device
framework will create the following sysfs structures:
/sys/devices/vfio_ap/matrix/
...... [mdev_supported_types]
......... [vfio_ap-passthrough]
............ create
To create a mediated device for the AP matrix device, write a UUID
to the create file:
uuidgen > create
A symbolic link to the mediated device's directory will be created in the
devices subdirectory named after the generated $uuid:
/sys/devices/vfio_ap/matrix/
...... [mdev_supported_types]
......... [vfio_ap-passthrough]
............ [devices]
............... [$uuid]
A symbolic link to the mediated device will also be created
in the vfio_ap matrix's directory:
/sys/devices/vfio_ap/matrix/[$uuid]
Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
Reviewed-by: Halil Pasic <pasic@xxxxxxxxxxxxx>
Tested-by: Michael Mueller <mimu@xxxxxxxxxxxxx>
Tested-by: Farhan Ali <alifm@xxxxxxxxxxxxx>
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
MAINTAINERS | 1 +
drivers/s390/crypto/Makefile | 2 +-
drivers/s390/crypto/vfio_ap_drv.c | 23 ++++++
drivers/s390/crypto/vfio_ap_ops.c | 124 +++++++++++++++++++++++++++++++++
drivers/s390/crypto/vfio_ap_private.h | 45 ++++++++++++
include/uapi/linux/vfio.h | 1 +
6 files changed, 195 insertions(+), 1 deletions(-)
create mode 100644 drivers/s390/crypto/vfio_ap_ops.c
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
new file mode 100644
index 0000000..8018c2d
--- /dev/null
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Adjunct processor matrix VFIO device driver callbacks.
+ *
+ * Copyright IBM Corp. 2018
+ *
+ * Author(s): Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
+ * Halil Pasic <pasic@xxxxxxxxxxxxx>
+ * Pierre Morel <pmorel@xxxxxxxxxxxxx>
+ */
+#include <linux/string.h>
+#include <linux/vfio.h>
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/ctype.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;
+
+ matrix_mdev = kzalloc(sizeof(*matrix_mdev), GFP_KERNEL);
+ if (!matrix_mdev)
+ return -ENOMEM;
+
+ matrix_mdev->name = dev_name(mdev_dev(mdev));
+ vfio_ap_matrix_init(&matrix_dev.info, &matrix_mdev->matrix);
+ mdev_set_drvdata(mdev, matrix_mdev);
+
+ if (atomic_dec_if_positive(&matrix_dev.available_instances) < 0) {
+ kfree(matrix_mdev);
+ return -EPERM;
+ }
Maybe move this check to the top of the function?
I am going to remove this check. Since we have added a mutex to lock the
matrix_dev, I see no need for the available_instances to be an atomic_t
type because we can update it while holding the matrix_dev lock when the
other updates are made to the matrix_dev.
+
+ mutex_lock(&matrix_dev.lock);
+ list_add(&matrix_mdev->list, &matrix_dev.mdev_list);
+ mutex_unlock(&matrix_dev.lock);
+
+ return 0;
+}