Merge remote-tracking branch 'remotes/dgilbert/tags/pull-migration-20180710a' into staging

Migration pull 2018-07-10 (for 3.0)

Migration fixes and migration test fixes, mostly
around postcopy and postcopy recovery

# gpg: Signature made Tue 10 Jul 2018 16:27:19 BST
# gpg:                using RSA key 0516331EBC5BFDE7
# gpg: Good signature from "Dr. David Alan Gilbert (RH2) <dgilbert@redhat.com>"
# Primary key fingerprint: 45F5 C71B 4A0C B7FB 977A  9FA9 0516 331E BC5B FDE7

* remotes/dgilbert/tags/pull-migration-20180710a:
  migration: reorder MIG_CMD_POSTCOPY_RESUME
  tests: hide stderr for postcopy recovery test
  tests: add postcopy recovery test
  tests: introduce wait_for_migration_status()
  tests: introduce migrate_query*() helpers
  tests: allow migrate() to take extra flags
  tests: introduce migrate_postcopy_* helpers
  migration: show pause/recover state on dst host
  migration: fix incorrect bitmap size calculation
  migration: loosen recovery check when load vm
  migration: simplify check to use qemu file buffer
  migration: unify incoming processing
  migration: unbreak postcopy recovery
  migration: move income process out of multifd
  migration: delay postcopy paused state

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 18 insertions, 14 deletions

diff --git a/migration/ram.c b/migration/ram.c
index 1cd98d6398..52dd678092 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -235,7 +235,7 @@ int64_t ramblock_recv_bitmap_send(QEMUFile *file,
     bitmap_to_le(le_bitmap, block->receivedmap, nbits);
 
     /* Size of the bitmap, in bytes */
-    size = nbits / 8;
+    size = DIV_ROUND_UP(nbits, 8);
 
     /*
      * size is always aligned to 8 bytes for 64bit machines, but it
@@ -1311,7 +1311,8 @@ bool multifd_recv_all_channels_created(void)
     return thread_count == atomic_read(&multifd_recv_state->count);
 }
 
-void multifd_recv_new_channel(QIOChannel *ioc)
+/* Return true if multifd is ready for the migration, otherwise false */
+bool multifd_recv_new_channel(QIOChannel *ioc)
 {
     MultiFDRecvParams *p;
     Error *local_err = NULL;
@@ -1320,7 +1321,7 @@ void multifd_recv_new_channel(QIOChannel *ioc)
     id = multifd_recv_initial_packet(ioc, &local_err);
     if (id < 0) {
         multifd_recv_terminate_threads(local_err);
-        return;
+        return false;
     }
 
     p = &multifd_recv_state->params[id];
@@ -1328,7 +1329,7 @@ void multifd_recv_new_channel(QIOChannel *ioc)
         error_setg(&local_err, "multifd: received id '%d' already setup'",
                    id);
         multifd_recv_terminate_threads(local_err);
-        return;
+        return false;
     }
     p->c = ioc;
     object_ref(OBJECT(ioc));
@@ -1339,9 +1340,7 @@ void multifd_recv_new_channel(QIOChannel *ioc)
     qemu_thread_create(&p->thread, p->name, multifd_recv_thread, p,
                        QEMU_THREAD_JOINABLE);
     atomic_inc(&multifd_recv_state->count);
-    if (multifd_recv_state->count == migrate_multifd_channels()) {
-        migration_incoming_process();
-    }
+    return multifd_recv_state->count == migrate_multifd_channels();
 }
 
 /**
@@ -3581,7 +3580,7 @@ static int ram_load_postcopy(QEMUFile *f)
 {
     int flags = 0, ret = 0;
     bool place_needed = false;
-    bool matching_page_sizes = false;
+    bool matches_target_page_size = false;
     MigrationIncomingState *mis = migration_incoming_get_current();
     /* Temporary page that is later 'placed' */
     void *postcopy_host_page = postcopy_get_tmp_page(mis);
@@ -3621,7 +3620,7 @@ static int ram_load_postcopy(QEMUFile *f)
                 ret = -EINVAL;
                 break;
             }
-            matching_page_sizes = block->page_size == TARGET_PAGE_SIZE;
+            matches_target_page_size = block->page_size == TARGET_PAGE_SIZE;
             /*
              * Postcopy requires that we place whole host pages atomically;
              * these may be huge pages for RAMBlocks that are backed by
@@ -3669,12 +3668,17 @@ static int ram_load_postcopy(QEMUFile *f)
 
         case RAM_SAVE_FLAG_PAGE:
             all_zero = false;
-            if (!place_needed || !matching_page_sizes) {
+            if (!matches_target_page_size) {
+                /* For huge pages, we always use temporary buffer */
                 qemu_get_buffer(f, page_buffer, TARGET_PAGE_SIZE);
             } else {
-                /* Avoids the qemu_file copy during postcopy, which is
-                 * going to do a copy later; can only do it when we
-                 * do this read in one go (matching page sizes)
+                /*
+                 * For small pages that matches target page size, we
+                 * avoid the qemu_file copy.  Instead we directly use
+                 * the buffer of QEMUFile to place the page.  Note: we
+                 * cannot do any QEMUFile operation before using that
+                 * buffer to make sure the buffer is valid when
+                 * placing the page.
                  */
                 qemu_get_buffer_in_place(f, (uint8_t **)&place_source,
                                          TARGET_PAGE_SIZE);
@@ -3940,7 +3944,7 @@ int ram_dirty_bitmap_reload(MigrationState *s, RAMBlock *block)
     int ret = -EINVAL;
     QEMUFile *file = s->rp_state.from_dst_file;
     unsigned long *le_bitmap, nbits = block->used_length >> TARGET_PAGE_BITS;
-    uint64_t local_size = nbits / 8;
+    uint64_t local_size = DIV_ROUND_UP(nbits, 8);
     uint64_t size, end_mark;
 
     trace_ram_dirty_bitmap_reload_begin(block->idstr);