This is an incremental step in converting vmstate loading
code to report error via Error objects instead of directly
printing it to console/monitor.
It is ensured that loadvm_process_enable_colo() must report an error
in errp, in case of failure.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Arun Menon <armenon@redhat.com>
---
 include/migration/colo.h |  2 +-
 migration/migration.c    | 12 ++++++------
 migration/ram.c          |  8 ++++----
 migration/ram.h          |  2 +-
 migration/savevm.c       | 26 ++++++++++++++------------
 5 files changed, 26 insertions(+), 24 deletions(-)

diff --git a/include/migration/colo.h b/include/migration/colo.h
index 43222ef5ae6adc3f7d8aa6a48bef79af33d09208..d4fe422e4d335d3bef4f860f56400fcd73287a0e 100644
--- a/include/migration/colo.h
+++ b/include/migration/colo.h
@@ -25,7 +25,7 @@ void migrate_start_colo_process(MigrationState *s);
 bool migration_in_colo_state(void);
 
 /* loadvm */
-int migration_incoming_enable_colo(void);
+int migration_incoming_enable_colo(Error **errp);
 void migration_incoming_disable_colo(void);
 bool migration_incoming_colo_enabled(void);
 bool migration_incoming_in_colo_state(void);
diff --git a/migration/migration.c b/migration/migration.c
index 16250faed91781843a572fe1ad4d71a37a2847a4..5d17e65bbf4c044ad9aac0f5f3fc9f5fefd71230 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -623,22 +623,22 @@ void migration_incoming_disable_colo(void)
     migration_colo_enabled = false;
 }
 
-int migration_incoming_enable_colo(void)
+int migration_incoming_enable_colo(Error **errp)
 {
 #ifndef CONFIG_REPLICATION
-    error_report("ENABLE_COLO command come in migration stream, but the "
-                 "replication module is not built in");
+    error_setg(errp, "ENABLE_COLO command come in migration stream, but the "
+               "replication module is not built in");
     return -ENOTSUP;
 #endif
 
     if (!migrate_colo()) {
-        error_report("ENABLE_COLO command come in migration stream, but x-colo "
-                     "capability is not set");
+        error_setg(errp, "ENABLE_COLO command come in migration stream"
+                   ", but x-colo capability is not set");
         return -EINVAL;
     }
 
     if (ram_block_discard_disable(true)) {
-        error_report("COLO: cannot disable RAM discard");
+        error_setg(errp, "COLO: cannot disable RAM discard");
         return -EBUSY;
     }
     migration_colo_enabled = true;
diff --git a/migration/ram.c b/migration/ram.c
index 163265a57f26fb1dc88d9797629d58c278e9afb7..a8e8d2cc6790336625de626fee070ecc51327200 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -3578,7 +3578,7 @@ static void colo_init_ram_state(void)
  *
  * Returns zero to indicate success or -1 on error.
  */
-int colo_init_ram_cache(void)
+int colo_init_ram_cache(Error **errp)
 {
     RAMBlock *block;
 
@@ -3587,9 +3587,9 @@ int colo_init_ram_cache(void)
             block->colo_cache = qemu_anon_ram_alloc(block->used_length,
                                                     NULL, false, false);
             if (!block->colo_cache) {
-                error_report("%s: Can't alloc memory for COLO cache of block %s,"
-                             "size 0x" RAM_ADDR_FMT, __func__, block->idstr,
-                             block->used_length);
+                error_setg(errp, "Can't alloc memory for COLO cache of "
+                           "block %s, size 0x" RAM_ADDR_FMT,
+                           block->idstr, block->used_length);
                 RAMBLOCK_FOREACH_NOT_IGNORED(block) {
                     if (block->colo_cache) {
                         qemu_anon_ram_free(block->colo_cache, block->used_length);
diff --git a/migration/ram.h b/migration/ram.h
index 275709a99187f9429ccb4111e05281ec268ba0db..24cd0bf585762cfa1e86834dc03c6baeea2f0627 100644
--- a/migration/ram.h
+++ b/migration/ram.h
@@ -109,7 +109,7 @@ void ramblock_set_file_bmap_atomic(RAMBlock *block, ram_addr_t offset,
                                    bool set);
 
 /* ram cache */
-int colo_init_ram_cache(void);
+int colo_init_ram_cache(Error **errp);
 void colo_flush_ram_cache(void);
 void colo_release_ram_cache(void);
 void colo_incoming_start_dirty_log(void);
diff --git a/migration/savevm.c b/migration/savevm.c
index 13a809564aebf6346228f46fd60f611ba6104bea..8e891243dc1e7f5d3bc3a4326c6c4a2f5c32e1a2 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -2515,15 +2515,21 @@ static int loadvm_handle_recv_bitmap(MigrationIncomingState *mis,
     return 0;
 }
 
-static int loadvm_process_enable_colo(MigrationIncomingState *mis)
+static int loadvm_process_enable_colo(MigrationIncomingState *mis,
+                                      Error **errp)
 {
-    int ret = migration_incoming_enable_colo();
+    ERRP_GUARD();
+    int ret;
 
-    if (!ret) {
-        ret = colo_init_ram_cache();
-        if (ret) {
-            migration_incoming_disable_colo();
-        }
+    ret = migration_incoming_enable_colo(errp);
+    if (ret < 0) {
+        return ret;
+    }
+
+    ret = colo_init_ram_cache(errp);
+    if (ret) {
+        error_prepend(errp, "failed to init colo RAM cache: %d: ", ret);
+        migration_incoming_disable_colo();
     }
     return ret;
 }
@@ -2646,11 +2652,7 @@ static int loadvm_process_command(QEMUFile *f, Error **errp)
         return loadvm_handle_recv_bitmap(mis, len, errp);
 
     case MIG_CMD_ENABLE_COLO:
-        ret = loadvm_process_enable_colo(mis);
-        if (ret < 0) {
-            error_setg(errp, "Failed to load device state command: %d", ret);
-        }
-        return ret;
+        return loadvm_process_enable_colo(mis, errp);
 
     case MIG_CMD_SWITCHOVER_START:
         ret = loadvm_postcopy_handle_switchover_start();

-- 
2.51.0