[dpdk-dev] [PATCH v3] vhost: add config change slave msg support

[Li Feng]

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
compacity of backend has changed.

Signed-off-by: Li Feng <fen...@smartx.com>
---
v3:
* Move the declare to rte_vhost.h
* Add the symbol in rte_vhost_version.map

v2:
* Fix a little log typo.

 lib/librte_vhost/rte_vhost.h           | 12 ++++++++++++
 lib/librte_vhost/rte_vhost_version.map |  1 +
 lib/librte_vhost/vhost_user.c          | 31 +++++++++++++++++++++++++++++++
 lib/librte_vhost/vhost_user.h          |  1 +
 4 files changed, 45 insertions(+)

diff --git a/lib/librte_vhost/rte_vhost.h b/lib/librte_vhost/rte_vhost.h
index 7b5dc87c2..fc28da264 100644
--- a/lib/librte_vhost/rte_vhost.h
+++ b/lib/librte_vhost/rte_vhost.h
@@ -977,6 +977,18 @@ __rte_experimental
 int
 rte_vhost_get_vdpa_device_id(int vid);
 
+/**
+ * Notify the guest that should get config from backend.
+ *
+ * @param vid
+ *  vhost device ID
+ * @return
+ *  0 on success, < 0 on failure
+ */
+__rte_experimental
+int
+rte_vhost_user_slave_config_change(int vid);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/librte_vhost/rte_vhost_version.map 
b/lib/librte_vhost/rte_vhost_version.map
index c512377fe..acf013d6d 100644
--- 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_user_slave_config_change;
 };
diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 0cfb8b792..10f2e47d5 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -2840,6 +2840,37 @@ 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)
+{
+       int ret;
+       struct VhostUserMsg msg = {
+               .request.slave = VHOST_USER_SLAVE_CONFIG_CHANGE_MSG,
+               .flags = VHOST_USER_VERSION,
+               .size = 0,
+       };
+
+       ret = send_vhost_message(dev->slave_req_fd, &msg);
+       if (ret < 0) {
+               RTE_LOG(ERR, VHOST_CONFIG,
+                               "Failed to send config change (%d)\n",
+                               ret);
+               return ret;
+       }
+
+       return 0;
+}
+
+int
+rte_vhost_user_slave_config_change(int vid)
+{
+       struct virtio_net *dev;
+       dev = get_device(vid);
+       if (!dev)
+               return -ENODEV;
+       return vhost_user_slave_config_change(dev);
+}
+
 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 6563f7315..86c364a93 100644
--- 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;
-- 
2.11.0


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