vdpa_sim_net: Add support for user supported devices

Enable user to create vdpasim net simulate devices.

Show vdpa management device that supports creating, deleting vdpa devices.

$ vdpa mgmtdev show
vdpasim_net:
  supported_classes
    net

$ vdpa mgmtdev show -jp
{
    "show": {
        "vdpasim_net": {
            "supported_classes": {
              "net"
        }
    }
}

Create a vdpa device of type networking named as "foo2" from
the management device vdpasim:

$ vdpa dev add mgmtdev vdpasim_net name foo2

Show the newly created vdpa device by its name:
$ vdpa dev show foo2
foo2: type network mgmtdev vdpasim_net vendor_id 0 max_vqs 2 max_vq_size 256

$ vdpa dev show foo2 -jp
{
    "dev": {
        "foo2": {
            "type": "network",
            "mgmtdev": "vdpasim_net",
            "vendor_id": 0,
            "max_vqs": 2,
            "max_vq_size": 256
        }
    }
}

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>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210105103203.82508-7-parav@nvidia.comSigned-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vdpa/vdpa_sim/vdpa_sim.c

@@ -235,7 +235,7 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr)
 		ops = &vdpasim_config_ops;
 
 	vdpasim = vdpa_alloc_device(struct vdpasim, vdpa, NULL, ops,
-				    dev_attr->nvqs, NULL);
+				    dev_attr->nvqs, dev_attr->name);
 	if (!vdpasim)
 		goto err_alloc;
 
@@ -249,6 +249,7 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr)
 	if (dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64)))
 		goto err_iommu;
 	set_dma_ops(dev, &vdpasim_dma_ops);
+	vdpasim->vdpa.mdev = dev_attr->mgmt_dev;
 
 	vdpasim->config = kzalloc(dev_attr->config_size, GFP_KERNEL);
 	if (!vdpasim->config)

drivers/vdpa/vdpa_sim/vdpa_sim.h

@@ -33,6 +33,8 @@ struct vdpasim_virtqueue {
 };
 
 struct vdpasim_dev_attr {
+	struct vdpa_mgmt_dev *mgmt_dev;
+	const char *name;
 	u64 supported_features;
 	size_t config_size;
 	size_t buffer_size;

drivers/vdpa/vdpa_sim/vdpa_sim_net.c

@@ -35,8 +35,6 @@ MODULE_PARM_DESC(macaddr, "Ethernet MAC address");
 
 static u8 macaddr_buf[ETH_ALEN];
 
-static struct vdpasim *vdpasim_net_dev;
-
 static void vdpasim_net_work(struct work_struct *work)
 {
 	struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
@@ -120,21 +118,23 @@ static void vdpasim_net_get_config(struct vdpasim *vdpasim, void *config)
 	memcpy(net_config->mac, macaddr_buf, ETH_ALEN);
 }
 
-static int __init vdpasim_net_init(void)
+static void vdpasim_net_mgmtdev_release(struct device *dev)
+{
+}
+
+static struct device vdpasim_net_mgmtdev = {
+	.init_name = "vdpasim_net",
+	.release = vdpasim_net_mgmtdev_release,
+};
+
+static int vdpasim_net_dev_add(struct vdpa_mgmt_dev *mdev, const char *name)
 {
 	struct vdpasim_dev_attr dev_attr = {};
+	struct vdpasim *simdev;
 	int ret;
 
-	if (macaddr) {
-		mac_pton(macaddr, macaddr_buf);
-		if (!is_valid_ether_addr(macaddr_buf)) {
-			ret = -EADDRNOTAVAIL;
-			goto out;
-		}
-	} else {
-		eth_random_addr(macaddr_buf);
-	}
-
+	dev_attr.mgmt_dev = mdev;
+	dev_attr.name = name;
 	dev_attr.id = VIRTIO_ID_NET;
 	dev_attr.supported_features = VDPASIM_NET_FEATURES;
 	dev_attr.nvqs = VDPASIM_NET_VQ_NUM;
@@ -143,29 +143,75 @@ static int __init vdpasim_net_init(void)
 	dev_attr.work_fn = vdpasim_net_work;
 	dev_attr.buffer_size = PAGE_SIZE;
 
-	vdpasim_net_dev = vdpasim_create(&dev_attr);
-	if (IS_ERR(vdpasim_net_dev)) {
-		ret = PTR_ERR(vdpasim_net_dev);
-		goto out;
+	simdev = vdpasim_create(&dev_attr);
+	if (IS_ERR(simdev))
+		return PTR_ERR(simdev);
+
+	ret = _vdpa_register_device(&simdev->vdpa);
+	if (ret)
+		goto reg_err;
+
+	return 0;
+
+reg_err:
+	put_device(&simdev->vdpa.dev);
+	return ret;
+}
+
+static void vdpasim_net_dev_del(struct vdpa_mgmt_dev *mdev,
+				struct vdpa_device *dev)
+{
+	struct vdpasim *simdev = container_of(dev, struct vdpasim, vdpa);
+
+	_vdpa_unregister_device(&simdev->vdpa);
+}
+
+static const struct vdpa_mgmtdev_ops vdpasim_net_mgmtdev_ops = {
+	.dev_add = vdpasim_net_dev_add,
+	.dev_del = vdpasim_net_dev_del
+};
+
+static struct virtio_device_id id_table[] = {
+	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
+	{ 0 },
+};
+
+static struct vdpa_mgmt_dev mgmt_dev = {
+	.device = &vdpasim_net_mgmtdev,
+	.id_table = id_table,
+	.ops = &vdpasim_net_mgmtdev_ops,
+};
+
+static int __init vdpasim_net_init(void)
+{
+	int ret;
+
+	if (macaddr) {
+		mac_pton(macaddr, macaddr_buf);
+		if (!is_valid_ether_addr(macaddr_buf))
+			return -EADDRNOTAVAIL;
+	} else {
+		eth_random_addr(macaddr_buf);
 	}
 
-	ret = vdpa_register_device(&vdpasim_net_dev->vdpa);
+	ret = device_register(&vdpasim_net_mgmtdev);
 	if (ret)
-		goto put_dev;
+		return ret;
 
+	ret = vdpa_mgmtdev_register(&mgmt_dev);
+	if (ret)
+		goto parent_err;
 	return 0;
 
-put_dev:
-	put_device(&vdpasim_net_dev->vdpa.dev);
-out:
+parent_err:
+	device_unregister(&vdpasim_net_mgmtdev);
 	return ret;
 }
 
 static void __exit vdpasim_net_exit(void)
 {
-	struct vdpa_device *vdpa = &vdpasim_net_dev->vdpa;
-
-	vdpa_unregister_device(vdpa);
+	vdpa_mgmtdev_unregister(&mgmt_dev);
+	device_unregister(&vdpasim_net_mgmtdev);
 }
 
 module_init(vdpasim_net_init);