migration: Introduce ignore-shared capability

We want to use local migration to update QEMU for running guests.
In this case we don't need to migrate shared (file backed) RAM.
So, add a capability to ignore such blocks during live migration.

Signed-off-by: Yury Kotov <yury-kotov@yandex-team.ru>
Message-Id: <20190215174548.2630-3-yury-kotov@yandex-team.ru>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/migration/migration.c b/migration/migration.c
index d45561f9b8..e823fd8b91 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -995,6 +995,11 @@ static bool migrate_caps_check(bool *cap_list,
             error_setg(errp, "Postcopy is not supported");
             return false;
         }
+
+        if (cap_list[MIGRATION_CAPABILITY_X_IGNORE_SHARED]) {
+            error_setg(errp, "Postcopy is not compatible with ignore-shared");
+            return false;
+        }
     }
 
     return true;
@@ -2074,6 +2079,15 @@ bool migrate_dirty_bitmaps(void)
     return s->enabled_capabilities[MIGRATION_CAPABILITY_DIRTY_BITMAPS];
 }
 
+bool migrate_ignore_shared(void)
+{
+    MigrationState *s;
+
+    s = migrate_get_current();
+
+    return s->enabled_capabilities[MIGRATION_CAPABILITY_X_IGNORE_SHARED];
+}
+
 bool migrate_use_events(void)
 {
     MigrationState *s;