vhost: support config change slave message

This msg is used to notify qemu that should get the config of backend.

For example, vhost-user-blk uses this msg to notify guest OS the
capacity of backend has changed.

The need_reply flag is not mandatory because it will block the sender
thread and master process will send get_config message to fetch the
configuration, this need an extra thread to process the vhost message.

Signed-off-by: Li Feng <fengli@smartx.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

diff --git a/lib/librte_vhost/rte_vhost.h b/lib/librte_vhost/rte_vhost.h
index 7b5dc87..c7b619a 100644 (file)
--- a/lib/librte_vhost/rte_vhost.h
+++ b/lib/librte_vhost/rte_vhost.h
@@ -10,6 +10,7 @@
  * Interface to vhost-user
  */
 
+#include <stdbool.h>
 #include <stdint.h>
 #include <sys/eventfd.h>
 
@@ -977,6 +978,20 @@ __rte_experimental
 int
 rte_vhost_get_vdpa_device_id(int vid);
 
+/**
+ * Notify the guest that should get virtio configuration space from backend.
+ *
+ * @param vid
+ *  vhost device ID
+ * @param need_reply
+ *  wait for the master response the status of this operation
+ * @return
+ *  0 on success, < 0 on failure
+ */
+__rte_experimental
+int
+rte_vhost_slave_config_change(int vid, bool need_reply);
+
 #ifdef __cplusplus
 }
 #endif

diff --git a/lib/librte_vhost/rte_vhost_version.map b/lib/librte_vhost/rte_vhost_version.map
index c512377..051d08c 100644 (file)
--- a/lib/librte_vhost/rte_vhost_version.map
+++ b/lib/librte_vhost/rte_vhost_version.map
@@ -65,4 +65,5 @@ EXPERIMENTAL {
        rte_vhost_clr_inflight_desc_packed;
        rte_vhost_get_vhost_ring_inflight;
        rte_vhost_get_vring_base_from_inflight;
+       rte_vhost_slave_config_change;
 };

diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 47db316..69b84a8 100644 (file)
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -2840,6 +2840,42 @@ vhost_user_iotlb_miss(struct virtio_net *dev, uint64_t iova, uint8_t perm)
        return 0;
 }
 
+static int
+vhost_user_slave_config_change(struct virtio_net *dev, bool need_reply)
+{
+       int ret;
+       struct VhostUserMsg msg = {
+               .request.slave = VHOST_USER_SLAVE_CONFIG_CHANGE_MSG,
+               .flags = VHOST_USER_VERSION,
+               .size = 0,
+       };
+
+       if (need_reply)
+               msg.flags |= VHOST_USER_NEED_REPLY;
+
+       ret = send_vhost_slave_message(dev, &msg);
+       if (ret < 0) {
+               VHOST_LOG_CONFIG(ERR,
+                               "Failed to send config change (%d)\n",
+                               ret);
+               return ret;
+       }
+
+       return process_slave_message_reply(dev, &msg);
+}
+
+int
+rte_vhost_slave_config_change(int vid, bool need_reply)
+{
+       struct virtio_net *dev;
+
+       dev = get_device(vid);
+       if (!dev)
+               return -ENODEV;
+
+       return vhost_user_slave_config_change(dev, need_reply);
+}
+
 static int vhost_user_slave_set_vring_host_notifier(struct virtio_net *dev,
                                                    int index, int fd,
                                                    uint64_t offset,

diff --git a/lib/librte_vhost/vhost_user.h b/lib/librte_vhost/vhost_user.h
index 6563f73..86c364a 100644 (file)
--- a/lib/librte_vhost/vhost_user.h
+++ b/lib/librte_vhost/vhost_user.h
@@ -62,6 +62,7 @@ typedef enum VhostUserRequest {
 typedef enum VhostUserSlaveRequest {
        VHOST_USER_SLAVE_NONE = 0,
        VHOST_USER_SLAVE_IOTLB_MSG = 1,
+       VHOST_USER_SLAVE_CONFIG_CHANGE_MSG = 2,
        VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG = 3,
        VHOST_USER_SLAVE_MAX
 } VhostUserSlaveRequest;