[PATCH 08/33] migration: push Error **errp into loadvm_process_command()

["Daniel P. Berrangé" <berrange@redhat.com>]

This is an incremental step in converting vmstate loading code to report
via Error objects instead of printing directly to the console/monitor.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 migration/savevm.c | 87 ++++++++++++++++++++++++++++++++++------------
 1 file changed, 64 insertions(+), 23 deletions(-)

diff --git a/migration/savevm.c b/migration/savevm.c
index 350d5a315a..450c36994f 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -2223,34 +2223,37 @@ static int loadvm_process_enable_colo(MigrationIncomingState *mis)
  * Process an incoming 'QEMU_VM_COMMAND'
  * 0           just a normal return
  * LOADVM_QUIT All good, but exit the loop
- * <0          Error
+ * -1          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);
 
     /* Check validity before continue processing of cmds */
     if (qemu_file_get_error(f)) {
-        return qemu_file_get_error(f);
+        error_setg(errp, "device state stream has error: %d",
+                   qemu_file_get_error(f));
+        return -1;
     }
 
     trace_loadvm_process_command(cmd, len);
     if (cmd >= MIG_CMD_MAX || cmd == MIG_CMD_INVALID) {
-        error_report("MIG_CMD 0x%x unknown (len 0x%x)", cmd, len);
-        return -EINVAL;
+        error_setg(errp, "MIG_CMD 0x%x unknown (len 0x%x)", cmd, len);
+        return -1;
     }
 
     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);
-        return -ERANGE;
+        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 -1;
     }
 
     switch (cmd) {
@@ -2262,7 +2265,7 @@ static int loadvm_process_command(QEMUFile *f)
         }
         mis->to_src_file = qemu_file_get_return_path(f);
         if (!mis->to_src_file) {
-            error_report("CMD_OPEN_RETURN_PATH failed");
+            error_setg(errp, "CMD_OPEN_RETURN_PATH failed");
             return -1;
         }
         break;
@@ -2271,36 +2274,76 @@ 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 -1;
+        }
+        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 -1;
+        }
+        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 -1;
+        }
+        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 -1;
+        }
+        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 -1;
+        }
+        return ret;
 
     case MIG_CMD_POSTCOPY_RESUME:
-        return loadvm_postcopy_handle_resume(mis);
+        ret = loadvm_postcopy_handle_resume(mis);
+        if (ret < 0) {
+            error_setg(errp, "Failed to load device state command: %d", ret);
+            return -1;
+        }
+        return ret;
 
     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 -1;
+        }
+        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 -1;
+        }
+        return ret;
     }
 
     return 0;
@@ -2618,11 +2661,9 @@ retry:
             }
             break;
         case QEMU_VM_COMMAND:
-            ret = loadvm_process_command(f);
+            ret = loadvm_process_command(f, errp);
             trace_qemu_loadvm_state_section_command(ret);
             if (ret < 0) {
-                error_setg(errp,
-                           "Failed to load device state command: %d", ret);
                 goto out;
             }
             if (ret == LOADVM_QUIT) {
-- 
2.29.2