Remus: Make xc_domain_restore loop until the fd is closed.

The tail containing the final PFN table, VCPU contexts and
shared_info_page is buffered, then the read loop is restarted.
After the first pass, incoming pages are buffered until the next tail
is read, completing a new consistent checkpoint. At this point, the
memory changes are applied and the loop begins again. When the fd read
fails, the tail buffer is processed.

Signed-off-by: Brendan Cully <brendan@cs.ubc.ca>

tools/python/xen/xend/XendCheckpoint.py

@@ -345,7 +345,7 @@ def restore(xd, fd, dominfo = None, paused = False, relocating = False):
 
         restore_image.setCpuid()
 
-        os.read(fd, 1)           # Wait for source to close connection
+        # xc_restore will wait for source to close connection
         
         dominfo.completeRestore(handler.store_mfn, handler.console_mfn)