vhost+postcopy: Transmit 'listen' to slave

Notify the vhost-user slave on reception of the 'postcopy-listen'
event from the source.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

2 files changed, 21 insertions, 0 deletions

diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c
index 9e31f47b7a..e53b1953df 100644
--- a/contrib/libvhost-user/libvhost-user.c
+++ b/contrib/libvhost-user/libvhost-user.c
@@ -98,6 +98,7 @@ vu_request_to_string(unsigned int req)
         REQ(VHOST_USER_GET_CONFIG),
         REQ(VHOST_USER_SET_CONFIG),
         REQ(VHOST_USER_POSTCOPY_ADVISE),
+        REQ(VHOST_USER_POSTCOPY_LISTEN),
         REQ(VHOST_USER_MAX),
     };
 #undef REQ
@@ -932,6 +933,22 @@ out:
 }
 
 static bool
+vu_set_postcopy_listen(VuDev *dev, VhostUserMsg *vmsg)
+{
+    vmsg->payload.u64 = -1;
+    vmsg->size = sizeof(vmsg->payload.u64);
+
+    if (dev->nregions) {
+        vu_panic(dev, "Regions already registered at postcopy-listen");
+        return true;
+    }
+    dev->postcopy_listening = true;
+
+    vmsg->flags = VHOST_USER_VERSION |  VHOST_USER_REPLY_MASK;
+    vmsg->payload.u64 = 0; /* Success */
+    return true;
+}
+static bool
 vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
 {
     int do_reply = 0;
@@ -1004,6 +1021,8 @@ vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
         break;
     case VHOST_USER_POSTCOPY_ADVISE:
         return vu_set_postcopy_advise(dev, vmsg);
+    case VHOST_USER_POSTCOPY_LISTEN:
+        return vu_set_postcopy_listen(dev, vmsg);
     default:
         vmsg_close_fds(vmsg);
         vu_panic(dev, "Unhandled request: %d", vmsg->request);
diff --git a/contrib/libvhost-user/libvhost-user.h b/contrib/libvhost-user/libvhost-user.h
index 074b7860f6..ed505cf0c1 100644
--- a/contrib/libvhost-user/libvhost-user.h
+++ b/contrib/libvhost-user/libvhost-user.h
@@ -86,6 +86,7 @@ typedef enum VhostUserRequest {
     VHOST_USER_CREATE_CRYPTO_SESSION = 26,
     VHOST_USER_CLOSE_CRYPTO_SESSION = 27,
     VHOST_USER_POSTCOPY_ADVISE  = 28,
+    VHOST_USER_POSTCOPY_LISTEN  = 29,
     VHOST_USER_MAX
 } VhostUserRequest;
 
@@ -285,6 +286,7 @@ struct VuDev {
 
     /* Postcopy data */
     int postcopy_ufd;
+    bool postcopy_listening;
 };
 
 typedef struct VuVirtqElement {