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

Signed-off-by: Arun Menon <armenon@redhat.com>
---
 migration/savevm.c | 26 ++++++++++++--------------
 1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/migration/savevm.c b/migration/savevm.c
index 509b71dc2666617ee3e7b707f46187ee5287d201..6f181c381dc6ecd996a1f8dbc25cceead7ebe014 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1996,7 +1996,7 @@ static int loadvm_postcopy_handle_advise(MigrationIncomingState *mis,
  * There can be 0..many of these messages, each encoding multiple pages.
  */
 static int loadvm_postcopy_ram_handle_discard(MigrationIncomingState *mis,
-                                              uint16_t len)
+                                              uint16_t len, Error **errp)
 {
     int tmp;
     char ramid[256];
@@ -2009,6 +2009,7 @@ static int loadvm_postcopy_ram_handle_discard(MigrationIncomingState *mis,
         /* 1st discard */
         tmp = postcopy_ram_prepare_discard(mis);
         if (tmp) {
+            error_setg(errp, "Failed to prepare for RAM discard: %d", tmp);
             return tmp;
         }
         break;
@@ -2018,8 +2019,8 @@ static int loadvm_postcopy_ram_handle_discard(MigrationIncomingState *mis,
         break;
 
     default:
-        error_report("CMD_POSTCOPY_RAM_DISCARD in wrong postcopy state (%d)",
-                     ps);
+        error_setg(errp, "CMD_POSTCOPY_RAM_DISCARD in wrong "
+                   "postcopy state (%d)", ps);
         return -1;
     }
     /* We're expecting a
@@ -2028,29 +2029,30 @@ static int loadvm_postcopy_ram_handle_discard(MigrationIncomingState *mis,
      *    then at least 1 16 byte chunk
     */
     if (len < (1 + 1 + 1 + 1 + 2 * 8)) {
-        error_report("CMD_POSTCOPY_RAM_DISCARD invalid length (%d)", len);
+        error_setg(errp, "CMD_POSTCOPY_RAM_DISCARD invalid length (%d)", len);
         return -1;
     }
 
     tmp = qemu_get_byte(mis->from_src_file);
     if (tmp != postcopy_ram_discard_version) {
-        error_report("CMD_POSTCOPY_RAM_DISCARD invalid version (%d)", tmp);
+        error_setg(errp, "CMD_POSTCOPY_RAM_DISCARD invalid version (%d)", tmp);
         return -1;
     }
 
     if (!qemu_get_counted_string(mis->from_src_file, ramid)) {
-        error_report("CMD_POSTCOPY_RAM_DISCARD Failed to read RAMBlock ID");
+        error_setg(errp, "CMD_POSTCOPY_RAM_DISCARD Failed to read "
+                   "RAMBlock ID");
         return -1;
     }
     tmp = qemu_get_byte(mis->from_src_file);
     if (tmp != 0) {
-        error_report("CMD_POSTCOPY_RAM_DISCARD missing nil (%d)", tmp);
+        error_setg(errp, "CMD_POSTCOPY_RAM_DISCARD missing nil (%d)", tmp);
         return -1;
     }
 
     len -= 3 + strlen(ramid);
     if (len % 16) {
-        error_report("CMD_POSTCOPY_RAM_DISCARD invalid length (%d)", len);
+        error_setg(errp, "CMD_POSTCOPY_RAM_DISCARD invalid length (%d)", len);
         return -1;
     }
     trace_loadvm_postcopy_ram_handle_discard_header(ramid, len);
@@ -2062,6 +2064,7 @@ static int loadvm_postcopy_ram_handle_discard(MigrationIncomingState *mis,
         len -= 16;
         int ret = ram_discard_range(ramid, start_addr, block_length);
         if (ret) {
+            error_setg(errp, "Failed to discard RAM range %s: %d", ramid, ret);
             return ret;
         }
     }
@@ -2627,12 +2630,7 @@ static int loadvm_process_command(QEMUFile *f, Error **errp)
         return loadvm_postcopy_handle_run(mis, errp);
 
     case MIG_CMD_POSTCOPY_RAM_DISCARD:
-        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;
+        return loadvm_postcopy_ram_handle_discard(mis, len, errp);
 
     case MIG_CMD_POSTCOPY_RESUME:
         ret = loadvm_postcopy_handle_resume(mis);

-- 
2.50.0