[PATCH 5/5] net/virtio-user: support vDPA configuration callback

[<skoteshwar@marvell.com>]

From: Satha Rao <skoteshwar@marvell.com>

Extended the vhost_vdpa_get_intr_fd API to create an event and
register for configuration callbacks with the vDPA backend. This
enhancement allows the virtio-user driver to handle configuration
changes more effectively.

Signed-off-by: Satha Rao <skoteshwar@marvell.com>
---
 drivers/net/virtio/virtio_user/vhost_vdpa.c   | 18 ++++++++++--
 .../net/virtio/virtio_user/virtio_user_dev.c  | 29 +++++++++++++++++++
 .../net/virtio/virtio_user/virtio_user_dev.h  |  2 ++
 3 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/drivers/net/virtio/virtio_user/vhost_vdpa.c b/drivers/net/virtio/virtio_user/vhost_vdpa.c
index e8aea54000..c9eaffce16 100644
--- a/drivers/net/virtio/virtio_user/vhost_vdpa.c
+++ b/drivers/net/virtio/virtio_user/vhost_vdpa.c
@@ -9,6 +9,7 @@
 #include <fcntl.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <sys/eventfd.h>
 
 #include <rte_memory.h>
 
@@ -634,10 +635,21 @@ vhost_vdpa_update_link_state(struct virtio_user_dev *dev)
 }
 
 static int
-vhost_vdpa_get_intr_fd(struct virtio_user_dev *dev __rte_unused)
+vhost_vdpa_get_intr_fd(struct virtio_user_dev *dev)
 {
-	/* No link state interrupt with Vhost-vDPA */
-	return -1;
+	int fd;
+
+	if (dev->cfg_epfd)
+		return dev->cfg_epfd;
+
+	fd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
+	if (fd < 0) {
+		PMD_DRV_LOG(ERR, "failed to create fd error, %s", strerror(errno));
+		fd = -1;
+	}
+	dev->cfg_epfd = fd;
+
+	return fd;
 }
 
 static int
diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
index 91ad1312f7..ea00eb50f5 100644
--- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
+++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
@@ -487,6 +487,21 @@ virtio_user_dev_get_speed_duplex_config(struct virtio_user_dev *dev, void *dst,
 	return ret;
 }
 
+int
+virtio_user_dev_set_config_call(struct virtio_user_dev *dev, int fd)
+{
+	int ret = 0;
+
+	if (!dev->ops->set_config_call)
+		return -ENOTSUP;
+
+	ret = dev->ops->set_config_call(dev, fd);
+	if (ret)
+		PMD_DRV_LOG(ERR, "(%s) Failed to set config call in device", dev->path);
+
+	return ret;
+}
+
 static int
 virtio_user_dev_init_notify(struct virtio_user_dev *dev)
 {
@@ -769,6 +784,7 @@ virtio_user_dev_init(struct virtio_user_dev *dev, char *path, uint16_t queues,
 	dev->unsupported_features = 0;
 	dev->backend_type = backend_type;
 	dev->ifname = *ifname;
+	dev->cfg_epfd = 0;
 
 	if (virtio_user_dev_setup(dev) < 0) {
 		PMD_INIT_LOG(ERR, "(%s) backend set up fails", dev->path);
@@ -863,6 +879,15 @@ virtio_user_dev_init(struct virtio_user_dev *dev, char *path, uint16_t queues,
 		}
 	}
 
+	/* vhost vdpa register valid fd to handle config callback */
+	if (dev->cfg_epfd) {
+		struct rte_eth_dev *eth_dev = &rte_eth_devices[dev->hw.port_id];
+
+		if (rte_intr_efd_counter_size_set(eth_dev->intr_handle, 8))
+			return -rte_errno;
+		virtio_user_dev_set_config_call(dev, dev->cfg_epfd);
+	}
+
 	*ifname = NULL;
 	return 0;
 
@@ -892,6 +917,10 @@ virtio_user_dev_uninit(struct virtio_user_dev *dev)
 
 	virtio_user_free_vrings(dev);
 
+	if (dev->cfg_epfd) {
+		close(dev->cfg_epfd);
+		dev->cfg_epfd = 0;
+	}
 	free(dev->ifname);
 
 	if (dev->is_server)
diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.h b/drivers/net/virtio/virtio_user/virtio_user_dev.h
index 57d75d1c53..1ad93521e3 100644
--- a/drivers/net/virtio/virtio_user/virtio_user_dev.h
+++ b/drivers/net/virtio/virtio_user/virtio_user_dev.h
@@ -31,6 +31,7 @@ struct virtio_user_dev {
 
 	int		*callfds;
 	int		*kickfds;
+	int		cfg_epfd; /* config callback interrupt */
 	int		mac_specified;
 	uint16_t	max_queue_pairs;
 	uint16_t	queue_pairs;
@@ -89,6 +90,7 @@ int virtio_user_dev_get_rss_config(struct virtio_user_dev *dev, void *dst, size_
 				   int length);
 int virtio_user_dev_get_speed_duplex_config(struct virtio_user_dev *dev, void *dst,
 					    size_t offset, int length);
+int virtio_user_dev_set_config_call(struct virtio_user_dev *dev, int fd);
 void virtio_user_dev_delayed_disconnect_handler(void *param);
 int virtio_user_dev_server_reconnect(struct virtio_user_dev *dev);
 extern const char * const virtio_user_backend_strings[];
-- 
2.25.1