Merge remote-tracking branch 'quintela/tags/migration/20170517' into staging

migration/next for 20170517

# gpg: Signature made Wed 17 May 2017 11:46:36 AM BST
# gpg:                using RSA key 0xF487EF185872D723
# gpg: Good signature from "Juan Quintela <quintela@redhat.com>"
# gpg:                 aka "Juan Quintela <quintela@trasno.org>"
# Primary key fingerprint: 1899 FF8E DEBF 58CC EE03  4B82 F487 EF18 5872 D723

* quintela/tags/migration/20170517:
  migration: Move check_migratable() into qdev.c
  migration: Move postcopy stuff to postcopy-ram.c
  migration: Move page_cache.c to migration/
  migration: Create migration/blocker.h
  ram: Rename RAM_SAVE_FLAG_COMPRESS to RAM_SAVE_FLAG_ZERO
  migration: Pass Error ** argument to {save,load}_vmstate
  migration: Fix regression with compression threads

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/migration/postcopy-ram.h b/migration/postcopy-ram.h
index 4c25f03be2..52d51e8007 100644
--- a/migration/postcopy-ram.h
+++ b/migration/postcopy-ram.h
@@ -81,6 +81,28 @@ int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from,
 int postcopy_place_page_zero(MigrationIncomingState *mis, void *host,
                              size_t pagesize);
 
+/* The current postcopy state is read/set by postcopy_state_get/set
+ * which update it atomically.
+ * The state is updated as postcopy messages are received, and
+ * in general only one thread should be writing to the state at any one
+ * time, initially the main thread and then the listen thread;
+ * Corner cases are where either thread finishes early and/or errors.
+ * The state is checked as messages are received to ensure that
+ * the source is sending us messages in the correct order.
+ * The state is also used by the RAM reception code to know if it
+ * has to place pages atomically, and the cleanup code at the end of
+ * the main thread to know if it has to delay cleanup until the end
+ * of postcopy.
+ */
+typedef enum {
+    POSTCOPY_INCOMING_NONE = 0,  /* Initial state - no postcopy */
+    POSTCOPY_INCOMING_ADVISE,
+    POSTCOPY_INCOMING_DISCARD,
+    POSTCOPY_INCOMING_LISTENING,
+    POSTCOPY_INCOMING_RUNNING,
+    POSTCOPY_INCOMING_END
+} PostcopyState;
+
 /*
  * Allocate a page of memory that can be mapped at a later point in time
  * using postcopy_place_page
@@ -88,4 +110,8 @@ int postcopy_place_page_zero(MigrationIncomingState *mis, void *host,
  */
 void *postcopy_get_tmp_page(MigrationIncomingState *mis);
 
+PostcopyState postcopy_state_get(void);
+/* Set the state and return the old state */
+PostcopyState postcopy_state_set(PostcopyState new_state);
+
 #endif