vfio/ap_ops: Convert to use vfio_register_group_dev()

This is straightforward conversion, the ap_matrix_mdev is actually serving
as the vfio_device and we can replace all the mdev_get_drvdata()'s with a
simple container_of() or a dev_get_drvdata() for sysfs paths.

Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Cornelia Huck <cohuck@redhat.com>
Cc: kvm@vger.kernel.org
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/0-v4-0203a4ab0596+f7-vfio_ap_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Author: jgunthorpe

drivers/s390/crypto/vfio_ap_ops.c

@@ -24,8 +24,9 @@
 #define VFIO_AP_MDEV_TYPE_HWVIRT "passthrough"
 #define VFIO_AP_MDEV_NAME_HWVIRT "VFIO AP Passthrough Device"
 
-static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev);
+static int vfio_ap_mdev_reset_queues(struct ap_matrix_mdev *matrix_mdev);
 static struct vfio_ap_queue *vfio_ap_find_queue(int apqn);
+static const struct vfio_device_ops vfio_ap_matrix_dev_ops;
 
 static int match_apqn(struct device *dev, const void *data)
 {
@@ -326,43 +327,57 @@ static void vfio_ap_matrix_init(struct ap_config_info *info,
 	matrix->adm_max = info->apxa ? info->Nd : 15;
 }
 
-static int vfio_ap_mdev_create(struct mdev_device *mdev)
+static int vfio_ap_mdev_probe(struct mdev_device *mdev)
 {
 	struct ap_matrix_mdev *matrix_mdev;
+	int ret;
 
 	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;
+		ret = -ENOMEM;
+		goto err_dec_available;
 	}
+	vfio_init_group_dev(&matrix_mdev->vdev, &mdev->dev,
+			    &vfio_ap_matrix_dev_ops);
 
 	matrix_mdev->mdev = mdev;
 	vfio_ap_matrix_init(&matrix_dev->info, &matrix_mdev->matrix);
-	mdev_set_drvdata(mdev, matrix_mdev);
 	matrix_mdev->pqap_hook = handle_pqap;
 	mutex_lock(&matrix_dev->lock);
 	list_add(&matrix_mdev->node, &matrix_dev->mdev_list);
 	mutex_unlock(&matrix_dev->lock);
 
+	ret = vfio_register_group_dev(&matrix_mdev->vdev);
+	if (ret)
+		goto err_list;
+	dev_set_drvdata(&mdev->dev, matrix_mdev);
 	return 0;
+
+err_list:
+	mutex_lock(&matrix_dev->lock);
+	list_del(&matrix_mdev->node);
+	mutex_unlock(&matrix_dev->lock);
+	kfree(matrix_mdev);
+err_dec_available:
+	atomic_inc(&matrix_dev->available_instances);
+	return ret;
 }
 
-static int vfio_ap_mdev_remove(struct mdev_device *mdev)
+static void vfio_ap_mdev_remove(struct mdev_device *mdev)
 {
-	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+	struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(&mdev->dev);
+
+	vfio_unregister_group_dev(&matrix_mdev->vdev);
 
 	mutex_lock(&matrix_dev->lock);
-	vfio_ap_mdev_reset_queues(mdev);
+	vfio_ap_mdev_reset_queues(matrix_mdev);
 	list_del(&matrix_mdev->node);
 	kfree(matrix_mdev);
-	mdev_set_drvdata(mdev, NULL);
 	atomic_inc(&matrix_dev->available_instances);
 	mutex_unlock(&matrix_dev->lock);
-
-	return 0;
 }
 
 static ssize_t name_show(struct mdev_type *mtype,
@@ -604,8 +619,7 @@ static ssize_t assign_adapter_store(struct device *dev,
 {
 	int ret;
 	unsigned long apid;
-	struct mdev_device *mdev = mdev_from_dev(dev);
-	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+	struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
 
 	mutex_lock(&matrix_dev->lock);
 
@@ -674,8 +688,7 @@ static ssize_t unassign_adapter_store(struct device *dev,
 {
 	int ret;
 	unsigned long apid;
-	struct mdev_device *mdev = mdev_from_dev(dev);
-	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+	struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
 
 	mutex_lock(&matrix_dev->lock);
 
@@ -760,8 +773,7 @@ static ssize_t assign_domain_store(struct device *dev,
 {
 	int ret;
 	unsigned long apqi;
-	struct mdev_device *mdev = mdev_from_dev(dev);
-	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+	struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
 	unsigned long max_apqi = matrix_mdev->matrix.aqm_max;
 
 	mutex_lock(&matrix_dev->lock);
@@ -826,8 +838,7 @@ static ssize_t unassign_domain_store(struct device *dev,
 {
 	int ret;
 	unsigned long apqi;
-	struct mdev_device *mdev = mdev_from_dev(dev);
-	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+	struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
 
 	mutex_lock(&matrix_dev->lock);
 
@@ -877,8 +888,7 @@ static ssize_t assign_control_domain_store(struct device *dev,
 {
 	int ret;
 	unsigned long id;
-	struct mdev_device *mdev = mdev_from_dev(dev);
-	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+	struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
 
 	mutex_lock(&matrix_dev->lock);
 
@@ -932,8 +942,7 @@ static ssize_t unassign_control_domain_store(struct device *dev,
 {
 	int ret;
 	unsigned long domid;
-	struct mdev_device *mdev = mdev_from_dev(dev);
-	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+	struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
 	unsigned long max_domid =  matrix_mdev->matrix.adm_max;
 
 	mutex_lock(&matrix_dev->lock);
@@ -968,8 +977,7 @@ static ssize_t control_domains_show(struct device *dev,
 	int nchars = 0;
 	int n;
 	char *bufpos = buf;
-	struct mdev_device *mdev = mdev_from_dev(dev);
-	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+	struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
 	unsigned long max_domid = matrix_mdev->matrix.adm_max;
 
 	mutex_lock(&matrix_dev->lock);
@@ -987,8 +995,7 @@ static DEVICE_ATTR_RO(control_domains);
 static ssize_t matrix_show(struct device *dev, struct device_attribute *attr,
 			   char *buf)
 {
-	struct mdev_device *mdev = mdev_from_dev(dev);
-	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+	struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
 	char *bufpos = buf;
 	unsigned long apid;
 	unsigned long apqi;
@@ -1165,7 +1172,7 @@ static void vfio_ap_mdev_unset_kvm(struct ap_matrix_mdev *matrix_mdev,
 		mutex_lock(&matrix_dev->lock);
 
 		kvm_arch_crypto_clear_masks(kvm);
-		vfio_ap_mdev_reset_queues(matrix_mdev->mdev);
+		vfio_ap_mdev_reset_queues(matrix_mdev);
 		kvm_put_kvm(kvm);
 		matrix_mdev->kvm = NULL;
 
@@ -1259,13 +1266,12 @@ int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q,
 	return ret;
 }
 
-static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev)
+static int vfio_ap_mdev_reset_queues(struct ap_matrix_mdev *matrix_mdev)
 {
 	int ret;
 	int rc = 0;
 	unsigned long apid, apqi;
 	struct vfio_ap_queue *q;
-	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
 
 	for_each_set_bit_inv(apid, matrix_mdev->matrix.apm,
 			     matrix_mdev->matrix.apm_max + 1) {
@@ -1286,49 +1292,45 @@ static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev)
 	return rc;
 }
 
-static int vfio_ap_mdev_open_device(struct mdev_device *mdev)
+static int vfio_ap_mdev_open_device(struct vfio_device *vdev)
 {
-	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+	struct ap_matrix_mdev *matrix_mdev =
+		container_of(vdev, struct ap_matrix_mdev, vdev);
 	unsigned long events;
 	int ret;
 
-
-	if (!try_module_get(THIS_MODULE))
-		return -ENODEV;
-
 	matrix_mdev->group_notifier.notifier_call = vfio_ap_mdev_group_notifier;
 	events = VFIO_GROUP_NOTIFY_SET_KVM;
 
-	ret = vfio_register_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
+	ret = vfio_register_notifier(vdev->dev, VFIO_GROUP_NOTIFY,
 				     &events, &matrix_mdev->group_notifier);
-	if (ret) {
-		module_put(THIS_MODULE);
+	if (ret)
 		return ret;
-	}
 
 	matrix_mdev->iommu_notifier.notifier_call = vfio_ap_mdev_iommu_notifier;
 	events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
-	ret = vfio_register_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
+	ret = vfio_register_notifier(vdev->dev, VFIO_IOMMU_NOTIFY,
 				     &events, &matrix_mdev->iommu_notifier);
-	if (!ret)
-		return ret;
+	if (ret)
+		goto out_unregister_group;
+	return 0;
 
-	vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
+out_unregister_group:
+	vfio_unregister_notifier(vdev->dev, VFIO_GROUP_NOTIFY,
 				 &matrix_mdev->group_notifier);
-	module_put(THIS_MODULE);
 	return ret;
 }
 
-static void vfio_ap_mdev_close_device(struct mdev_device *mdev)
+static void vfio_ap_mdev_close_device(struct vfio_device *vdev)
 {
-	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+	struct ap_matrix_mdev *matrix_mdev =
+		container_of(vdev, struct ap_matrix_mdev, vdev);
 
-	vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
+	vfio_unregister_notifier(vdev->dev, VFIO_IOMMU_NOTIFY,
 				 &matrix_mdev->iommu_notifier);
-	vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
+	vfio_unregister_notifier(vdev->dev, VFIO_GROUP_NOTIFY,
 				 &matrix_mdev->group_notifier);
 	vfio_ap_mdev_unset_kvm(matrix_mdev, matrix_mdev->kvm);
-	module_put(THIS_MODULE);
 }
 
 static int vfio_ap_mdev_get_device_info(unsigned long arg)
@@ -1351,25 +1353,20 @@ static int vfio_ap_mdev_get_device_info(unsigned long arg)
 	return copy_to_user((void __user *)arg, &info, minsz) ? -EFAULT : 0;
 }
 
-static ssize_t vfio_ap_mdev_ioctl(struct mdev_device *mdev,
+static ssize_t vfio_ap_mdev_ioctl(struct vfio_device *vdev,
 				    unsigned int cmd, unsigned long arg)
 {
+	struct ap_matrix_mdev *matrix_mdev =
+		container_of(vdev, struct ap_matrix_mdev, vdev);
 	int ret;
-	struct ap_matrix_mdev *matrix_mdev;
 
 	mutex_lock(&matrix_dev->lock);
 	switch (cmd) {
 	case VFIO_DEVICE_GET_INFO:
 		ret = vfio_ap_mdev_get_device_info(arg);
 		break;
 	case VFIO_DEVICE_RESET:
-		matrix_mdev = mdev_get_drvdata(mdev);
-		if (WARN(!matrix_mdev, "Driver data missing from mdev!!")) {
-			ret = -EINVAL;
-			break;
-		}
-
-		ret = vfio_ap_mdev_reset_queues(mdev);
+		ret = vfio_ap_mdev_reset_queues(matrix_mdev);
 		break;
 	default:
 		ret = -EOPNOTSUPP;
@@ -1380,25 +1377,51 @@ static ssize_t vfio_ap_mdev_ioctl(struct mdev_device *mdev,
 	return ret;
 }
 
+static const struct vfio_device_ops vfio_ap_matrix_dev_ops = {
+	.open_device = vfio_ap_mdev_open_device,
+	.close_device = vfio_ap_mdev_close_device,
+	.ioctl = vfio_ap_mdev_ioctl,
+};
+
+static struct mdev_driver vfio_ap_matrix_driver = {
+	.driver = {
+		.name = "vfio_ap_mdev",
+		.owner = THIS_MODULE,
+		.mod_name = KBUILD_MODNAME,
+		.dev_groups = vfio_ap_mdev_attr_groups,
+	},
+	.probe = vfio_ap_mdev_probe,
+	.remove = vfio_ap_mdev_remove,
+};
+
 static const struct mdev_parent_ops vfio_ap_matrix_ops = {
 	.owner			= THIS_MODULE,
+	.device_driver		= &vfio_ap_matrix_driver,
 	.supported_type_groups	= vfio_ap_mdev_type_groups,
-	.mdev_attr_groups	= vfio_ap_mdev_attr_groups,
-	.create			= vfio_ap_mdev_create,
-	.remove			= vfio_ap_mdev_remove,
-	.open_device		= vfio_ap_mdev_open_device,
-	.close_device		= vfio_ap_mdev_close_device,
-	.ioctl			= vfio_ap_mdev_ioctl,
 };
 
 int vfio_ap_mdev_register(void)
 {
+	int ret;
+
 	atomic_set(&matrix_dev->available_instances, MAX_ZDEV_ENTRIES_EXT);
 
-	return mdev_register_device(&matrix_dev->device, &vfio_ap_matrix_ops);
+	ret = mdev_register_driver(&vfio_ap_matrix_driver);
+	if (ret)
+		return ret;
+
+	ret = mdev_register_device(&matrix_dev->device, &vfio_ap_matrix_ops);
+	if (ret)
+		goto err_driver;
+	return 0;
+
+err_driver:
+	mdev_unregister_driver(&vfio_ap_matrix_driver);
+	return ret;
 }
 
 void vfio_ap_mdev_unregister(void)
 {
 	mdev_unregister_device(&matrix_dev->device);
+	mdev_unregister_driver(&vfio_ap_matrix_driver);
 }

drivers/s390/crypto/vfio_ap_private.h

@@ -18,6 +18,7 @@
 #include <linux/delay.h>
 #include <linux/mutex.h>
 #include <linux/kvm_host.h>
+#include <linux/vfio.h>
 
 #include "ap_bus.h"
 
@@ -79,6 +80,7 @@ struct ap_matrix {
  * @kvm:	the struct holding guest's state
  */
 struct ap_matrix_mdev {
+	struct vfio_device vdev;
 	struct list_head node;
 	struct ap_matrix matrix;
 	struct notifier_block group_notifier;