migration: introduce decompress-error-check

QEMU 3.0 enables strict check for compression & decompression to
make the migration more robust, that depends on the source to fix
the internal design which triggers the unexpected error conditions

To make it work for migrating old version QEMU to 2.13 QEMU, we
introduce this parameter to disable the error check on the
destination which is the default behavior of the machine type
which is older than 2.13, alternately, the strict check can be
enabled explicitly as followings:
      -M pc-q35-2.11 -global migration.decompress-error-check=true

Signed-off-by: Xiao Guangrong <xiaoguangrong@tencent.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/migration/migration.h b/migration/migration.h
index 8f0c821..5af57d6 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -212,6 +212,13 @@ struct MigrationState
     /* Needed by postcopy-pause state */
     QemuSemaphore postcopy_pause_sem;
     QemuSemaphore postcopy_pause_rp_sem;
+    /*
+     * Whether we abort the migration if decompression errors are
+     * detected at the destination. It is left at false for qemu
+     * older than 3.0, since only newer qemu sends streams that
+     * do not trigger spurious decompression errors.
+     */
+    bool decompress_error_check;
 };
 
 void migrate_set_state(int *state, int old_state, int new_state);