live migration: Allow cleanup after cancellation or error

Introduce qemu_savevm_state_cancel and inject a stage -1 to cancel a
live migration. This gives the involved subsystems a chance to clean up
dynamically allocated resources. Namely, the block migration layer can
now free its device descriptors and pending blocks.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/vl.c b/vl.c
index 62427b8f9..f6c655b8d 100644
--- a/vl.c
+++ b/vl.c
@@ -2934,6 +2934,11 @@ static int ram_save_live(QEMUFile *f, int stage, void *opaque)
     double bwidth = 0;
     uint64_t expected_time = 0;
 
+    if (stage < 0) {
+        cpu_physical_memory_set_dirty_tracking(0);
+        return 0;
+    }
+
     if (cpu_physical_sync_dirty_bitmap(0, TARGET_PHYS_ADDR_MAX) != 0) {
         qemu_file_set_error(f);
         return 0;