libvhost-user: Fix VHOST_USER_ADD_MEM_REG reply

With REPLY_NEEDED, libvhost-user sends both the acutal result and an
additional ACK reply for VHOST_USER_ADD_MEM_REG. This is incorrect, the
spec mandates that it behave the same with and without REPLY_NEEDED
because it always sends a reply.

Fixes: ec94c8e621de96c50c2d381c8c9ec94f5beec7c1
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20220627134500.94842-4-kwolf@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/subprojects/libvhost-user/libvhost-user.c b/subprojects/libvhost-user/libvhost-user.c
index cfa1bcc..ffed472 100644 (file)
--- a/subprojects/libvhost-user/libvhost-user.c
+++ b/subprojects/libvhost-user/libvhost-user.c
@@ -779,15 +779,9 @@ vu_add_mem_reg(VuDev *dev, VhostUserMsg *vmsg) {
 
         /* Send the message back to qemu with the addresses filled in. */
         vmsg->fd_num = 0;
-        if (!vu_send_reply(dev, dev->sock, vmsg)) {
-            vu_panic(dev, "failed to respond to add-mem-region for postcopy");
-            return false;
-        }
-
         DPRINT("Successfully added new region in postcopy\n");
         dev->nregions++;
-        return false;
-
+        return true;
     } else {
         for (i = 0; i < dev->max_queues; i++) {
             if (dev->vq[i].vring.desc) {