vdpa: Enable a user to add and delete a vdpa device

Add the ability to add and delete a vdpa device.

Examples:
Create a vdpa device of type network named "foo2" from
the management device vdpasim:

$ vdpa dev add mgmtdev vdpasim_net name foo2

Delete the vdpa device after its use:
$ vdpa dev del foo2

Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Eli Cohen <elic@nvidia.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210105103203.82508-5-parav@nvidia.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index 586e66b7f67175e12318c0f8b0c69703e3215d84..f1228189814fa5e353726bfd984bd62c55ecab46 100644 (file)
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -136,6 +136,37 @@ static int vdpa_name_match(struct device *dev, const void *data)
        return (strcmp(dev_name(&vdev->dev), data) == 0);
 }
 
+static int __vdpa_register_device(struct vdpa_device *vdev)
+{
+       struct device *dev;
+
+       lockdep_assert_held(&vdpa_dev_mutex);
+       dev = bus_find_device(&vdpa_bus, NULL, dev_name(&vdev->dev), vdpa_name_match);
+       if (dev) {
+               put_device(dev);
+               return -EEXIST;
+       }
+       return device_add(&vdev->dev);
+}
+
+/**
+ * _vdpa_register_device - register a vDPA device with vdpa lock held
+ * Caller must have a succeed call of vdpa_alloc_device() before.
+ * Caller must invoke this routine in the management device dev_add()
+ * callback after setting up valid mgmtdev for this vdpa device.
+ * @vdev: the vdpa device to be registered to vDPA bus
+ *
+ * Returns an error when fail to add device to vDPA bus
+ */
+int _vdpa_register_device(struct vdpa_device *vdev)
+{
+       if (!vdev->mdev)
+               return -EINVAL;
+
+       return __vdpa_register_device(vdev);
+}
+EXPORT_SYMBOL_GPL(_vdpa_register_device);
+
 /**
  * vdpa_register_device - register a vDPA device
  * Callers must have a succeed call of vdpa_alloc_device() before.
@@ -145,24 +176,29 @@ static int vdpa_name_match(struct device *dev, const void *data)
  */
 int vdpa_register_device(struct vdpa_device *vdev)
 {
-       struct device *dev;
        int err;
 
        mutex_lock(&vdpa_dev_mutex);
-       dev = bus_find_device(&vdpa_bus, NULL, dev_name(&vdev->dev), vdpa_name_match);
-       if (dev) {
-               put_device(dev);
-               err = -EEXIST;
-               goto name_err;
-       }
-
-       err = device_add(&vdev->dev);
-name_err:
+       err = __vdpa_register_device(vdev);
        mutex_unlock(&vdpa_dev_mutex);
        return err;
 }
 EXPORT_SYMBOL_GPL(vdpa_register_device);
 
+/**
+ * _vdpa_unregister_device - unregister a vDPA device
+ * Caller must invoke this routine as part of management device dev_del()
+ * callback.
+ * @vdev: the vdpa device to be unregisted from vDPA bus
+ */
+void _vdpa_unregister_device(struct vdpa_device *vdev)
+{
+       lockdep_assert_held(&vdpa_dev_mutex);
+       WARN_ON(!vdev->mdev);
+       device_unregister(&vdev->dev);
+}
+EXPORT_SYMBOL_GPL(_vdpa_unregister_device);
+
 /**
  * vdpa_unregister_device - unregister a vDPA device
  * @vdev: the vdpa device to be unregisted from vDPA bus
@@ -221,10 +257,25 @@ int vdpa_mgmtdev_register(struct vdpa_mgmt_dev *mdev)
 }
 EXPORT_SYMBOL_GPL(vdpa_mgmtdev_register);
 
+static int vdpa_match_remove(struct device *dev, void *data)
+{
+       struct vdpa_device *vdev = container_of(dev, struct vdpa_device, dev);
+       struct vdpa_mgmt_dev *mdev = vdev->mdev;
+
+       if (mdev == data)
+               mdev->ops->dev_del(mdev, vdev);
+       return 0;
+}
+
 void vdpa_mgmtdev_unregister(struct vdpa_mgmt_dev *mdev)
 {
        mutex_lock(&vdpa_dev_mutex);
+
        list_del(&mdev->list);
+
+       /* Filter out all the entries belong to this management device and delete it. */
+       bus_for_each_dev(&vdpa_bus, NULL, mdev, vdpa_match_remove);
+
        mutex_unlock(&vdpa_dev_mutex);
 }
 EXPORT_SYMBOL_GPL(vdpa_mgmtdev_unregister);
@@ -368,9 +419,69 @@ out:
        return msg->len;
 }
 
+static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *info)
+{
+       struct vdpa_mgmt_dev *mdev;
+       const char *name;
+       int err = 0;
+
+       if (!info->attrs[VDPA_ATTR_DEV_NAME])
+               return -EINVAL;
+
+       name = nla_data(info->attrs[VDPA_ATTR_DEV_NAME]);
+
+       mutex_lock(&vdpa_dev_mutex);
+       mdev = vdpa_mgmtdev_get_from_attr(info->attrs);
+       if (IS_ERR(mdev)) {
+               NL_SET_ERR_MSG_MOD(info->extack, "Fail to find the specified management device");
+               err = PTR_ERR(mdev);
+               goto err;
+       }
+
+       err = mdev->ops->dev_add(mdev, name);
+err:
+       mutex_unlock(&vdpa_dev_mutex);
+       return err;
+}
+
+static int vdpa_nl_cmd_dev_del_set_doit(struct sk_buff *skb, struct genl_info *info)
+{
+       struct vdpa_mgmt_dev *mdev;
+       struct vdpa_device *vdev;
+       struct device *dev;
+       const char *name;
+       int err = 0;
+
+       if (!info->attrs[VDPA_ATTR_DEV_NAME])
+               return -EINVAL;
+       name = nla_data(info->attrs[VDPA_ATTR_DEV_NAME]);
+
+       mutex_lock(&vdpa_dev_mutex);
+       dev = bus_find_device(&vdpa_bus, NULL, name, vdpa_name_match);
+       if (!dev) {
+               NL_SET_ERR_MSG_MOD(info->extack, "device not found");
+               err = -ENODEV;
+               goto dev_err;
+       }
+       vdev = container_of(dev, struct vdpa_device, dev);
+       if (!vdev->mdev) {
+               NL_SET_ERR_MSG_MOD(info->extack, "Only user created device can be deleted by user");
+               err = -EINVAL;
+               goto mdev_err;
+       }
+       mdev = vdev->mdev;
+       mdev->ops->dev_del(mdev, vdev);
+mdev_err:
+       put_device(dev);
+dev_err:
+       mutex_unlock(&vdpa_dev_mutex);
+       return err;
+}
+
 static const struct nla_policy vdpa_nl_policy[VDPA_ATTR_MAX + 1] = {
        [VDPA_ATTR_MGMTDEV_BUS_NAME] = { .type = NLA_NUL_STRING },
        [VDPA_ATTR_MGMTDEV_DEV_NAME] = { .type = NLA_STRING },
+       [VDPA_ATTR_DEV_NAME] = { .type = NLA_STRING },
 };
 
 static const struct genl_ops vdpa_nl_ops[] = {
@@ -380,6 +491,18 @@ static const struct genl_ops vdpa_nl_ops[] = {
                .doit = vdpa_nl_cmd_mgmtdev_get_doit,
                .dumpit = vdpa_nl_cmd_mgmtdev_get_dumpit,
        },
+       {
+               .cmd = VDPA_CMD_DEV_NEW,
+               .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+               .doit = vdpa_nl_cmd_dev_add_set_doit,
+               .flags = GENL_ADMIN_PERM,
+       },
+       {
+               .cmd = VDPA_CMD_DEV_DEL,
+               .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+               .doit = vdpa_nl_cmd_dev_del_set_doit,
+               .flags = GENL_ADMIN_PERM,
+       },
 };
 
 static struct genl_family vdpa_nl_family __ro_after_init = {

diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index 6b8b4222bca647139316eb5b8ab407e288b341fc..4ab5494503a830db9aa22ea64440bd4e92d48f2f 100644 (file)
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h
@@ -45,6 +45,8 @@ struct vdpa_mgmt_dev;
  * @index: device index
  * @features_valid: were features initialized? for legacy guests
  * @nvqs: maximum number of supported virtqueues
+ * @mdev: management device pointer; caller must setup when registering device as part
+ *       of dev_add() mgmtdev ops callback before invoking _vdpa_register_device().
  */
 struct vdpa_device {
        struct device dev;
@@ -53,6 +55,7 @@ struct vdpa_device {
        unsigned int index;
        bool features_valid;
        int nvqs;
+       struct vdpa_mgmt_dev *mdev;
 };
 
 /**
@@ -260,6 +263,9 @@ struct vdpa_device *__vdpa_alloc_device(struct device *parent,
 int vdpa_register_device(struct vdpa_device *vdev);
 void vdpa_unregister_device(struct vdpa_device *vdev);
 
+int _vdpa_register_device(struct vdpa_device *vdev);
+void _vdpa_unregister_device(struct vdpa_device *vdev);
+
 /**
  * vdpa_driver - operations for a vDPA driver
  * @driver: underlying device driver

diff --git a/include/uapi/linux/vdpa.h b/include/uapi/linux/vdpa.h
index d44d82e567b12fdf473bb157b3b224eeac399944..bb4a1f00eb1cd8a5b0432e72c2f8bf942421bfa3 100644 (file)
--- a/include/uapi/linux/vdpa.h
+++ b/include/uapi/linux/vdpa.h
@@ -14,6 +14,8 @@ enum vdpa_command {
        VDPA_CMD_UNSPEC,
        VDPA_CMD_MGMTDEV_NEW,
        VDPA_CMD_MGMTDEV_GET,           /* can dump */
+       VDPA_CMD_DEV_NEW,
+       VDPA_CMD_DEV_DEL,
 };
 
 enum vdpa_attr {
@@ -24,6 +26,8 @@ enum vdpa_attr {
        VDPA_ATTR_MGMTDEV_DEV_NAME,             /* string */
        VDPA_ATTR_MGMTDEV_SUPPORTED_CLASSES,    /* u64 */
 
+       VDPA_ATTR_DEV_NAME,                     /* string */
+
        /* new attributes must be added above here */
        VDPA_ATTR_MAX,
 };