[PATCH RFC 4/5] cpu: Allow cpu_synchronize_all_post_init() to take an errp

[Peter Xu <peterx@redhat.com>]

Allow cpu_synchronize_all_post_init() to fail with an errp when it's set.
Modify both precopy and postcopy to try to detect such error.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/core/machine.c     |  2 +-
 include/sysemu/cpus.h |  2 +-
 migration/savevm.c    | 20 +++++++++++++++++---
 softmmu/cpus.c        |  2 +-
 4 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index c53548d0b1..b5daad82f8 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -1447,7 +1447,7 @@ void qemu_remove_machine_init_done_notifier(Notifier *notify)
 
 void qdev_machine_creation_done(void)
 {
-    cpu_synchronize_all_post_init();
+    cpu_synchronize_all_post_init(NULL);
 
     if (current_machine->boot_config.has_once) {
         qemu_boot_set(current_machine->boot_config.once, &error_fatal);
diff --git a/include/sysemu/cpus.h b/include/sysemu/cpus.h
index b5c87d48b3..a51ee46441 100644
--- a/include/sysemu/cpus.h
+++ b/include/sysemu/cpus.h
@@ -45,7 +45,7 @@ bool cpus_are_resettable(void);
 
 void cpu_synchronize_all_states(void);
 void cpu_synchronize_all_post_reset(void);
-void cpu_synchronize_all_post_init(void);
+void cpu_synchronize_all_post_init(Error **errp);
 void cpu_synchronize_all_pre_loadvm(void);
 
 #ifndef CONFIG_USER_ONLY
diff --git a/migration/savevm.c b/migration/savevm.c
index d9076897b8..1175ddefd4 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -2005,7 +2005,17 @@ static void loadvm_postcopy_handle_run_bh(void *opaque)
     /* TODO we should move all of this lot into postcopy_ram.c or a shared code
      * in migration.c
      */
-    cpu_synchronize_all_post_init();
+    cpu_synchronize_all_post_init(&local_err);
+    if (local_err) {
+        /*
+         * TODO: a better way to do this is to tell the src that we cannot
+         * run the VM here so hopefully we can keep the VM running on src
+         * and immediately halt the switch-over.  But that needs work.
+         */
+        error_report_err(local_err);
+        local_err = NULL;
+        autostart = false;
+    }
 
     trace_loadvm_postcopy_handle_run_bh("after cpu sync");
 
@@ -2772,7 +2782,11 @@ int qemu_loadvm_state(QEMUFile *f)
     }
 
     qemu_loadvm_state_cleanup();
-    cpu_synchronize_all_post_init();
+    cpu_synchronize_all_post_init(&local_err);
+    if (local_err) {
+        error_report_err(local_err);
+        return -EINVAL;
+    }
 
     return ret;
 }
@@ -2789,7 +2803,7 @@ int qemu_load_device_state(QEMUFile *f)
         return ret;
     }
 
-    cpu_synchronize_all_post_init();
+    cpu_synchronize_all_post_init(NULL);
     return 0;
 }
 
diff --git a/softmmu/cpus.c b/softmmu/cpus.c
index 464c06201c..59c70fd496 100644
--- a/softmmu/cpus.c
+++ b/softmmu/cpus.c
@@ -146,7 +146,7 @@ void cpu_synchronize_all_post_reset(void)
     }
 }
 
-void cpu_synchronize_all_post_init(void)
+void cpu_synchronize_all_post_init(Error **errp)
 {
     CPUState *cpu;
 
-- 
2.32.0