[PATCH] vhost-user: add NEED_REPLY flag

[luzhixing12345 <luzhixing12345@gmail.com>]

Front-end message requests which need reply should set NEED_REPLY_MASK
in flag, and response from slave need clear NEED_REPLY_MASK flag.

---
 hw/virtio/vhost-user.c                    | 2 +-
 subprojects/libvhost-user/libvhost-user.c | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 00561daa06..edf2271e0a 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -1082,7 +1082,7 @@ static int vhost_user_get_u64(struct vhost_dev *dev, int request, uint64_t *u64)
     int ret;
     VhostUserMsg msg = {
         .hdr.request = request,
-        .hdr.flags = VHOST_USER_VERSION,
+        .hdr.flags = VHOST_USER_VERSION | VHOST_USER_NEED_REPLY_MASK,
     };
 
     if (vhost_user_per_device_request(request) && dev->vq_index != 0) {
diff --git a/subprojects/libvhost-user/libvhost-user.c b/subprojects/libvhost-user/libvhost-user.c
index 9c630c2170..40f665bd7f 100644
--- a/subprojects/libvhost-user/libvhost-user.c
+++ b/subprojects/libvhost-user/libvhost-user.c
@@ -667,6 +667,7 @@ vu_send_reply(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
 {
     /* Set the version in the flags when sending the reply */
     vmsg->flags &= ~VHOST_USER_VERSION_MASK;
+    vmsg->flags &= ~VHOST_USER_NEED_REPLY_MASK;
     vmsg->flags |= VHOST_USER_VERSION;
     vmsg->flags |= VHOST_USER_REPLY_MASK;
 
-- 
2.34.1