[dpdk-dev] [RFC 09/10] vhost: add support to postcopy's end request

[Maxime Coquelin <maxime.coquelin@redhat.com>]

The master sends this message before stopping handling
userfaults, so that the backend closes the userfaultfd.

The master waits for the slave to acknowledge the request
with an empty 64bits payload for synchronization purpose.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 lib/librte_vhost/vhost_user.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 29e3e2a07..54692775c 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -75,6 +75,7 @@ static const char *vhost_message_str[VHOST_USER_MAX] = {
 	[VHOST_USER_CRYPTO_CLOSE_SESS] = "VHOST_USER_CRYPTO_CLOSE_SESS",
 	[VHOST_USER_POSTCOPY_ADVISE]  = "VHOST_USER_POSTCOPY_ADVISE",
 	[VHOST_USER_POSTCOPY_LISTEN]  = "VHOST_USER_POSTCOPY_LISTEN",
+	[VHOST_USER_POSTCOPY_END]  = "VHOST_USER_POSTCOPY_END",
 };
 
 static int
@@ -1512,6 +1513,18 @@ vhost_user_set_postcopy_listen(struct virtio_net *dev)
 	return 0;
 }
 
+static int
+vhost_user_postcopy_end(struct virtio_net *dev)
+{
+	dev->postcopy_listening = 0;
+	if (dev->postcopy_ufd > 0) {
+		close(dev->postcopy_ufd);
+		dev->postcopy_ufd = -1;
+	}
+
+	return 0;
+}
+
 /* return bytes# of read on success or negative val on failure. */
 static int
 read_vhost_message(int sockfd, struct VhostUserMsg *msg)
@@ -1864,6 +1877,14 @@ vhost_user_msg_handler(int vid, int fd)
 		ret = vhost_user_set_postcopy_listen(dev);
 		break;
 
+	case VHOST_USER_POSTCOPY_END:
+		vhost_user_postcopy_end(dev);
+		msg.payload.u64 = 0;
+		msg.size = sizeof(msg.payload.u64);
+		msg.fd_num = 0;
+		send_vhost_reply(fd, &msg);
+		break;
+
 	default:
 		ret = -1;
 		break;
-- 
2.17.1