[PATCH v7 09/24] migration: push Error **errp into loadvm_process_command()

[Arun Menon <armenon@redhat.com>]

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_command() must report an error
in errp, in case of failure.

Signed-off-by: Arun Menon <armenon@redhat.com>
---
 migration/savevm.c | 73 +++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 53 insertions(+), 20 deletions(-)

diff --git a/migration/savevm.c b/migration/savevm.c
index ad96da3651b89023e4b70ffeecab46d176bae6f5..d40b25d74be46b209be8f28d10b7538a5ff2e3dd 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -2544,12 +2544,13 @@ static int loadvm_postcopy_handle_switchover_start(void)
  * LOADVM_QUIT All good, but exit the loop
  * <0          Error
  */
-static int loadvm_process_command(QEMUFile *f)
+static int loadvm_process_command(QEMUFile *f, Error **errp)
 {
     MigrationIncomingState *mis = migration_incoming_get_current();
     uint16_t cmd;
     uint16_t len;
     uint32_t tmp32;
+    int ret;
 
     cmd = qemu_get_be16(f);
     len = qemu_get_be16(f);
@@ -2560,16 +2561,16 @@ static int loadvm_process_command(QEMUFile *f)
     }
 
     if (cmd >= MIG_CMD_MAX || cmd == MIG_CMD_INVALID) {
-        error_report("MIG_CMD 0x%x unknown (len 0x%x)", cmd, len);
+        error_setg(errp, "MIG_CMD 0x%x unknown (len 0x%x)", cmd, len);
         return -EINVAL;
     }
 
     trace_loadvm_process_command(mig_cmd_args[cmd].name, len);
 
     if (mig_cmd_args[cmd].len != -1 && mig_cmd_args[cmd].len != len) {
-        error_report("%s received with bad length - expecting %zu, got %d",
-                     mig_cmd_args[cmd].name,
-                     (size_t)mig_cmd_args[cmd].len, len);
+        error_setg(errp, "%s received with bad length - expecting %zu, got %d",
+                   mig_cmd_args[cmd].name,
+                   (size_t)mig_cmd_args[cmd].len, len);
         return -ERANGE;
     }
 
@@ -2588,11 +2589,11 @@ static int loadvm_process_command(QEMUFile *f)
          * been created.
          */
         if (migrate_switchover_ack() && !mis->switchover_ack_pending_num) {
-            int ret = migrate_send_rp_switchover_ack(mis);
+            ret = migrate_send_rp_switchover_ack(mis);
             if (ret) {
-                error_report(
-                    "Could not send switchover ack RP MSG, err %d (%s)", ret,
-                    strerror(-ret));
+                error_setg(errp,
+                           "Could not send switchover ack RP MSG, err %d (%s)",
+                           ret, strerror(-ret));
                 return ret;
             }
         }
@@ -2602,40 +2603,72 @@ static int loadvm_process_command(QEMUFile *f)
         tmp32 = qemu_get_be32(f);
         trace_loadvm_process_command_ping(tmp32);
         if (!mis->to_src_file) {
-            error_report("CMD_PING (0x%x) received with no return path",
-                         tmp32);
+            error_setg(errp, "CMD_PING (0x%x) received with no return path",
+                       tmp32);
             return -1;
         }
         migrate_send_rp_pong(mis, tmp32);
         break;
 
     case MIG_CMD_PACKAGED:
-        return loadvm_handle_cmd_packaged(mis);
+        ret = loadvm_handle_cmd_packaged(mis);
+        if (ret < 0) {
+            error_setg(errp, "Failed to load device state command: %d", ret);
+        }
+        return ret;
 
     case MIG_CMD_POSTCOPY_ADVISE:
-        return loadvm_postcopy_handle_advise(mis, len);
+        ret = loadvm_postcopy_handle_advise(mis, len);
+        if (ret < 0) {
+            error_setg(errp, "Failed to load device state command: %d", ret);
+        }
+        return ret;
 
     case MIG_CMD_POSTCOPY_LISTEN:
-        return loadvm_postcopy_handle_listen(mis);
+        ret = loadvm_postcopy_handle_listen(mis);
+        if (ret < 0) {
+            error_setg(errp, "Failed to load device state command: %d", ret);
+        }
+        return ret;
 
     case MIG_CMD_POSTCOPY_RUN:
-        return loadvm_postcopy_handle_run(mis);
+        ret = loadvm_postcopy_handle_run(mis);
+        if (ret < 0) {
+            error_setg(errp, "Failed to load device state command: %d", ret);
+        }
+        return ret;
 
     case MIG_CMD_POSTCOPY_RAM_DISCARD:
-        return loadvm_postcopy_ram_handle_discard(mis, len);
+        ret = loadvm_postcopy_ram_handle_discard(mis, len);
+        if (ret < 0) {
+            error_setg(errp, "Failed to load device state command: %d", ret);
+        }
+        return ret;
 
     case MIG_CMD_POSTCOPY_RESUME:
         loadvm_postcopy_handle_resume(mis);
         return 0;
 
     case MIG_CMD_RECV_BITMAP:
-        return loadvm_handle_recv_bitmap(mis, len);
+        ret = loadvm_handle_recv_bitmap(mis, len);
+        if (ret < 0) {
+            error_setg(errp, "Failed to load device state command: %d", ret);
+        }
+        return ret;
 
     case MIG_CMD_ENABLE_COLO:
-        return loadvm_process_enable_colo(mis);
+        ret = loadvm_process_enable_colo(mis);
+        if (ret < 0) {
+            error_setg(errp, "Failed to load device state command: %d", ret);
+        }
+        return ret;
 
     case MIG_CMD_SWITCHOVER_START:
-        return loadvm_postcopy_handle_switchover_start();
+        ret = loadvm_postcopy_handle_switchover_start();
+        if (ret < 0) {
+            error_setg(errp, "Failed to load device state command: %d", ret);
+        }
+        return ret;
     }
 
     return 0;
@@ -3075,7 +3108,7 @@ retry:
             }
             break;
         case QEMU_VM_COMMAND:
-            ret = loadvm_process_command(f);
+            ret = loadvm_process_command(f, NULL);
             trace_qemu_loadvm_state_section_command(ret);
             if ((ret < 0) || (ret == LOADVM_QUIT)) {
                 goto out;

-- 
2.50.0