[PULL 15/45] migration: push Error **errp into loadvm_postcopy_handle_advise()

[Peter Xu <peterx@redhat.com>]

From: 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_postcopy_handle_advise() must report an error
in errp, in case of failure.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Arun Menon <armenon@redhat.com>
Tested-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
Link: https://lore.kernel.org/r/20250918-propagate_tpm_error-v14-15-36f11a6fb9d3@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 migration/savevm.c | 40 +++++++++++++++++++---------------------
 1 file changed, 19 insertions(+), 21 deletions(-)

diff --git a/migration/savevm.c b/migration/savevm.c
index 338d1a9756..38e22b435b 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1912,39 +1912,39 @@ enum LoadVMExitCodes {
  * quickly.
  */
 static int loadvm_postcopy_handle_advise(MigrationIncomingState *mis,
-                                         uint16_t len)
+                                         uint16_t len, Error **errp)
 {
     PostcopyState ps = postcopy_state_set(POSTCOPY_INCOMING_ADVISE);
     uint64_t remote_pagesize_summary, local_pagesize_summary, remote_tps;
     size_t page_size = qemu_target_page_size();
-    Error *local_err = NULL;
 
     trace_loadvm_postcopy_handle_advise();
     if (ps != POSTCOPY_INCOMING_NONE) {
-        error_report("CMD_POSTCOPY_ADVISE in wrong postcopy state (%d)", ps);
+        error_setg(errp, "CMD_POSTCOPY_ADVISE in wrong postcopy state (%d)",
+                   ps);
         return -1;
     }
 
     switch (len) {
     case 0:
         if (migrate_postcopy_ram()) {
-            error_report("RAM postcopy is enabled but have 0 byte advise");
+            error_setg(errp, "RAM postcopy is enabled but have 0 byte advise");
             return -EINVAL;
         }
         return 0;
     case 8 + 8:
         if (!migrate_postcopy_ram()) {
-            error_report("RAM postcopy is disabled but have 16 byte advise");
+            error_setg(errp,
+                       "RAM postcopy is disabled but have 16 byte advise");
             return -EINVAL;
         }
         break;
     default:
-        error_report("CMD_POSTCOPY_ADVISE invalid length (%d)", len);
+        error_setg(errp, "CMD_POSTCOPY_ADVISE invalid length (%d)", len);
         return -EINVAL;
     }
 
-    if (!postcopy_ram_supported_by_host(mis, &local_err)) {
-        error_report_err(local_err);
+    if (!postcopy_ram_supported_by_host(mis, errp)) {
         postcopy_state_set(POSTCOPY_INCOMING_NONE);
         return -1;
     }
@@ -1967,9 +1967,10 @@ static int loadvm_postcopy_handle_advise(MigrationIncomingState *mis,
          *      also fails when passed to an older qemu that doesn't
          *      do huge pages.
          */
-        error_report("Postcopy needs matching RAM page sizes (s=%" PRIx64
-                                                             " d=%" PRIx64 ")",
-                     remote_pagesize_summary, local_pagesize_summary);
+        error_setg(errp,
+                   "Postcopy needs matching RAM page sizes "
+                   "(s=%" PRIx64 " d=%" PRIx64 ")",
+                   remote_pagesize_summary, local_pagesize_summary);
         return -1;
     }
 
@@ -1979,17 +1980,18 @@ static int loadvm_postcopy_handle_advise(MigrationIncomingState *mis,
          * Again, some differences could be dealt with, but for now keep it
          * simple.
          */
-        error_report("Postcopy needs matching target page sizes (s=%d d=%zd)",
-                     (int)remote_tps, page_size);
+        error_setg(errp,
+                   "Postcopy needs matching target page sizes (s=%d d=%zd)",
+                   (int)remote_tps, page_size);
         return -1;
     }
 
-    if (postcopy_notify(POSTCOPY_NOTIFY_INBOUND_ADVISE, &local_err)) {
-        error_report_err(local_err);
+    if (postcopy_notify(POSTCOPY_NOTIFY_INBOUND_ADVISE, errp)) {
         return -1;
     }
 
-    if (ram_postcopy_incoming_init(mis, NULL) < 0) {
+    if (ram_postcopy_incoming_init(mis, errp) < 0) {
+        error_prepend(errp, "Postcopy RAM incoming init failed: ");
         return -1;
     }
 
@@ -2617,11 +2619,7 @@ static int loadvm_process_command(QEMUFile *f, Error **errp)
         return loadvm_handle_cmd_packaged(mis, errp);
 
     case MIG_CMD_POSTCOPY_ADVISE:
-        ret = loadvm_postcopy_handle_advise(mis, len);
-        if (ret < 0) {
-            error_setg(errp, "Failed to load device state command: %d", ret);
-        }
-        return ret;
+        return loadvm_postcopy_handle_advise(mis, len, errp);
 
     case MIG_CMD_POSTCOPY_LISTEN:
         ret = loadvm_postcopy_handle_listen(mis);
-- 
2.50.1