vm/windows: Wait for migration to finish.

This ensures that the intermediate machine is shut down only after the
migration has finished writing the memory dump to disk, to ensure we
don't end up with empty state files depending on how fast the migration
finished before we actually shut down the VM.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

pkgs/build-support/vm/windows/bootstrap.nix

@@ -1,6 +1,6 @@
 { stdenv, fetchurl, vmTools, writeScript, writeText, runCommand, makeInitrd
 , python, perl, coreutils, dosfstools, gzip, mtools, netcat, openssh, qemu
-, samba, socat, vde2, cdrkit, pathsFromGraph
+, samba, socat, vde2, cdrkit, pathsFromGraph, gnugrep
 }:
 
 { isoFile, productKey, arch ? null }:
@@ -10,7 +10,7 @@ with stdenv.lib;
 let
   controller = import ./controller {
     inherit stdenv writeScript vmTools makeInitrd;
-    inherit samba vde2 openssh socat netcat coreutils gzip;
+    inherit samba vde2 openssh socat netcat coreutils gzip gnugrep;
   };
 
   mkCygwinImage = import ./cygwin-iso {

pkgs/build-support/vm/windows/controller/default.nix

@@ -1,5 +1,5 @@
 { stdenv, writeScript, vmTools, makeInitrd
-, samba, vde2, openssh, socat, netcat, coreutils, gzip
+, samba, vde2, openssh, socat, netcat, coreutils, gnugrep, gzip
 }:
 
 { sshKey
@@ -217,17 +217,26 @@ let
     fi
   '';
 
+  toMonitor = "${socat}/bin/socat - UNIX-CONNECT:$MONITOR_SOCKET";
+
   postVM = if suspendTo != null then ''
     while ! test -e "$XCHG_DIR/suspend_now"; do
       ${checkDropOut}
       ${coreutils}/bin/sleep 1
     done
-    ${socat}/bin/socat - UNIX-CONNECT:$MONITOR_SOCKET <<CMD
+    ${toMonitor} <<CMD
     stop
     migrate_set_speed 4095m
     migrate "exec:${gzip}/bin/gzip -c > '${suspendTo}'"
-    quit
     CMD
+    echo -n "Waiting for memory dump to finish..."
+    while ! echo info migrate | ${toMonitor} | \
+          ${gnugrep}/bin/grep -qi '^migration *status: *complete'; do
+      ${coreutils}/bin/sleep 1
+      echo -n .
+    done
+    echo " done."
+    echo quit | ${toMonitor}
     wait $(< "$WINVM_PIDFILE")
     eval "$postVM"
     exit 0

pkgs/build-support/vm/windows/default.nix

@@ -5,6 +5,7 @@ let
     inherit (pkgs) stdenv vmTools writeScript writeText runCommand makeInitrd;
     inherit (pkgs) coreutils dosfstools gzip mtools netcat openssh qemu samba;
     inherit (pkgs) socat vde2 fetchurl python perl cdrkit pathsFromGraph;
+    inherit (pkgs) gnugrep;
   };
 
   builder = ''