libxc/save: Write a v3 stream

Introduce a new static_data() hook which is responsible for writing out
any static data records.  The HVM side continues to be a no-op, while
the PV side moves write_x86_pv_info() into this earlier hook.  The the
common code writes out a STATIC_DATA_END record, and the stream version
is bumped to 3.

Update convert-legacy-stream to write a v3 stream, because this will
bypass the compatibly logic in libxc.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

tools/python/scripts/convert-legacy-stream

@@ -79,7 +79,7 @@ def write_libxc_ihdr():
     stream_write(pack(libxc.IHDR_FORMAT,
                       libxc.IHDR_MARKER,  # Marker
                       libxc.IHDR_IDENT,   # Ident
-                      2,                  # Version
+                      3,                  # Version
                       libxc.IHDR_OPT_LE,  # Options
                       0, 0))              # Reserved
 
@@ -166,6 +166,9 @@ def write_libxc_hvm_params(params):
                  pack(libxc.HVM_PARAMS_FORMAT, len(params) / 2, 0),
                  pack("Q" * len(params), *params))
 
+def write_libxc_static_data_end():
+    write_record(libxc.REC_TYPE_static_data_end)
+
 def write_libxl_end():
     write_record(libxl.REC_TYPE_end)
 
@@ -590,6 +593,10 @@ def read_legacy_stream(vm):
 
         if pv:
             read_pv_extended_info(vm)
+
+        write_libxc_static_data_end()
+
+        if pv:
             read_pv_p2m_frames(vm)
 
         read_chunks(vm)