vdpa_sim_net: Enable user to set mac address and mtu

Enable user to set the mac address and mtu so that each vdpa device
can have its own user specified mac address and mtu.

Now that user is enabled to set the mac address, remove the module
parameter for same.

And example of setting mac addr and mtu and view the configuration:
$ vdpa mgmtdev show
vdpasim_net:
  supported_classes net

$ vdpa dev add name bar mgmtdev vdpasim_net mac 00:11:22:33:44:55 mtu 9000

$ vdpa dev config show
bar: mac 00:11:22:33:44:55 link up link_announce false mtu 9000
Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Eli Cohen <elic@nvidia.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/20211026175519.87795-6-parav@nvidia.comSigned-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vdpa/vdpa_sim/vdpa_sim_net.c

@@ -16,6 +16,7 @@
 #include <linux/vringh.h>
 #include <linux/vdpa.h>
 #include <uapi/linux/virtio_net.h>
+#include <uapi/linux/vdpa.h>
 
 #include "vdpa_sim.h"
 
@@ -29,12 +30,6 @@
 
 #define VDPASIM_NET_VQ_NUM	2
 
-static char *macaddr;
-module_param(macaddr, charp, 0);
-MODULE_PARM_DESC(macaddr, "Ethernet MAC address");
-
-static u8 macaddr_buf[ETH_ALEN];
-
 static void vdpasim_net_work(struct work_struct *work)
 {
 	struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
@@ -112,9 +107,21 @@ static void vdpasim_net_get_config(struct vdpasim *vdpasim, void *config)
 {
 	struct virtio_net_config *net_config = config;
 
-	net_config->mtu = cpu_to_vdpasim16(vdpasim, 1500);
 	net_config->status = cpu_to_vdpasim16(vdpasim, VIRTIO_NET_S_LINK_UP);
-	memcpy(net_config->mac, macaddr_buf, ETH_ALEN);
+}
+
+static void vdpasim_net_setup_config(struct vdpasim *vdpasim,
+				     const struct vdpa_dev_set_config *config)
+{
+	struct virtio_net_config *vio_config = vdpasim->config;
+
+	if (config->mask & (1 << VDPA_ATTR_DEV_NET_CFG_MACADDR))
+		memcpy(vio_config->mac, config->net.mac, ETH_ALEN);
+	if (config->mask & (1 << VDPA_ATTR_DEV_NET_CFG_MTU))
+		vio_config->mtu = cpu_to_vdpasim16(vdpasim, config->net.mtu);
+	else
+		/* Setup default MTU to be 1500 */
+		vio_config->mtu = cpu_to_vdpasim16(vdpasim, 1500);
 }
 
 static void vdpasim_net_mgmtdev_release(struct device *dev)
@@ -147,6 +154,8 @@ static int vdpasim_net_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
 	if (IS_ERR(simdev))
 		return PTR_ERR(simdev);
 
+	vdpasim_net_setup_config(simdev, config);
+
 	ret = _vdpa_register_device(&simdev->vdpa, VDPASIM_NET_VQ_NUM);
 	if (ret)
 		goto reg_err;
@@ -180,20 +189,14 @@ static struct vdpa_mgmt_dev mgmt_dev = {
 	.device = &vdpasim_net_mgmtdev,
 	.id_table = id_table,
 	.ops = &vdpasim_net_mgmtdev_ops,
+	.config_attr_mask = (1 << VDPA_ATTR_DEV_NET_CFG_MACADDR |
+			     1 << VDPA_ATTR_DEV_NET_CFG_MTU),
 };
 
 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 = device_register(&vdpasim_net_mgmtdev);
 	if (ret)
 		return ret;