[PATCH v5 19/23] migration: push Error **errp into qemu_loadvm_state()

Arun Menon posted 23 patches 4 months ago
Maintainers: Stefan Berger <stefanb@linux.vnet.ibm.com>, "Alex Bennée" <alex.bennee@linaro.org>, Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>, Dmitry Osipenko <dmitry.osipenko@collabora.com>, "Michael S. Tsirkin" <mst@redhat.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Cornelia Huck <cohuck@redhat.com>, Halil Pasic <pasic@linux.ibm.com>, Eric Farman <farman@linux.ibm.com>, Thomas Huth <thuth@redhat.com>, Christian Borntraeger <borntraeger@linux.ibm.com>, Matthew Rosato <mjrosato@linux.ibm.com>, Richard Henderson <richard.henderson@linaro.org>, David Hildenbrand <david@redhat.com>, Ilya Leoshkevich <iii@linux.ibm.com>, Paolo Bonzini <pbonzini@redhat.com>, Fam Zheng <fam@euphon.net>, Nicholas Piggin <npiggin@gmail.com>, Daniel Henrique Barboza <danielhb413@gmail.com>, Harsh Prateek Bora <harshpb@linux.ibm.com>, Alex Williamson <alex.williamson@redhat.com>, "Cédric Le Goater" <clg@redhat.com>, Hailiang Zhang <zhanghailiang@xfusion.com>, Peter Xu <peterx@redhat.com>, Fabiano Rosas <farosas@suse.de>, Steve Sistare <steven.sistare@oracle.com>, "Marc-André Lureau" <marcandre.lureau@redhat.com>
There is a newer version of this series
[PATCH v5 19/23] migration: push Error **errp into qemu_loadvm_state()
Posted by Arun Menon 4 months ago
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 qemu_loadvm_state() must report an error
in errp, in case of failure.

Signed-off-by: Arun Menon <armenon@redhat.com>
---
 migration/migration.c |  5 +++--
 migration/savevm.c    | 25 +++++++++++++------------
 migration/savevm.h    |  2 +-
 3 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 326487882c8d41e2f89f99f69df0d9d4d42705e4..1f0a8bd6ab28ff09bb76919564bdbfbde35c5e42 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -881,7 +881,7 @@ process_incoming_migration_co(void *opaque)
                       MIGRATION_STATUS_ACTIVE);
 
     mis->loadvm_co = qemu_coroutine_self();
-    ret = qemu_loadvm_state(mis->from_src_file);
+    ret = qemu_loadvm_state(mis->from_src_file, &local_err);
     mis->loadvm_co = NULL;
 
     trace_vmstate_downtime_checkpoint("dst-precopy-loadvm-completed");
@@ -908,7 +908,8 @@ process_incoming_migration_co(void *opaque)
     }
 
     if (ret < 0) {
-        error_setg(&local_err, "load of migration failed: %s", strerror(-ret));
+        error_prepend(&local_err, "load of migration failed: %s ",
+                      strerror(-ret));
         goto fail;
     }
 
diff --git a/migration/savevm.c b/migration/savevm.c
index 47c656734248c2b7a6d2001c6ef9b3e83af11bac..ea64603b75ead17bcc21aebfa49ede3991387fb7 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -3133,27 +3133,24 @@ out:
     return ret;
 }
 
-int qemu_loadvm_state(QEMUFile *f)
+int qemu_loadvm_state(QEMUFile *f, Error **errp)
 {
     MigrationState *s = migrate_get_current();
     MigrationIncomingState *mis = migration_incoming_get_current();
-    Error *local_err = NULL;
     int ret;
 
-    if (qemu_savevm_state_blocked(&local_err)) {
-        error_report_err(local_err);
+    if (qemu_savevm_state_blocked(errp)) {
         return -EINVAL;
     }
 
     qemu_loadvm_thread_pool_create(mis);
 
-    ret = qemu_loadvm_state_header(f, NULL);
+    ret = qemu_loadvm_state_header(f, errp);
     if (ret) {
         return ret;
     }
 
-    if (qemu_loadvm_state_setup(f, &local_err) != 0) {
-        error_report_err(local_err);
+    if (qemu_loadvm_state_setup(f, errp) != 0) {
         return -EINVAL;
     }
 
@@ -3163,7 +3160,7 @@ int qemu_loadvm_state(QEMUFile *f)
 
     cpu_synchronize_all_pre_loadvm();
 
-    ret = qemu_loadvm_state_main(f, mis, NULL);
+    ret = qemu_loadvm_state_main(f, mis, errp);
     qemu_event_set(&mis->main_thread_load_event);
 
     trace_qemu_loadvm_state_post_main(ret);
@@ -3181,8 +3178,12 @@ int qemu_loadvm_state(QEMUFile *f)
         if (migrate_has_error(migrate_get_current()) ||
             !qemu_loadvm_thread_pool_wait(s, mis)) {
             ret = -EINVAL;
+            error_setg(errp, "Error while loading vmstate : %d", ret);
         } else {
             ret = qemu_file_get_error(f);
+            if (ret < 0) {
+                error_setg(errp, "Error while loading vmstate : %d", ret);
+            }
         }
     }
     /*
@@ -3468,10 +3469,10 @@ void qmp_xen_load_devices_state(const char *filename, Error **errp)
     f = qemu_file_new_input(QIO_CHANNEL(ioc));
     object_unref(OBJECT(ioc));
 
-    ret = qemu_loadvm_state(f);
+    ret = qemu_loadvm_state(f, errp);
     qemu_fclose(f);
     if (ret < 0) {
-        error_setg(errp, "loading Xen device state failed");
+        error_prepend(errp, "loading Xen device state failed ");
     }
     migration_incoming_state_destroy();
 }
@@ -3542,13 +3543,13 @@ bool load_snapshot(const char *name, const char *vmstate,
         ret = -EINVAL;
         goto err_drain;
     }
-    ret = qemu_loadvm_state(f);
+    ret = qemu_loadvm_state(f, errp);
     migration_incoming_state_destroy();
 
     bdrv_drain_all_end();
 
     if (ret < 0) {
-        error_setg(errp, "Error %d while loading VM state", ret);
+        error_prepend(errp, "Error %d while loading VM state ", ret);
         return false;
     }
 
diff --git a/migration/savevm.h b/migration/savevm.h
index fd7419e6ff90062970ed246b3ea71e6d49a6e372..a6df5198f3fe1a39fc0e6ce3e79cf7a5d8e032db 100644
--- a/migration/savevm.h
+++ b/migration/savevm.h
@@ -64,7 +64,7 @@ void qemu_savevm_send_colo_enable(QEMUFile *f);
 void qemu_savevm_live_state(QEMUFile *f);
 int qemu_save_device_state(QEMUFile *f);
 
-int qemu_loadvm_state(QEMUFile *f);
+int qemu_loadvm_state(QEMUFile *f, Error **errp);
 void qemu_loadvm_state_cleanup(MigrationIncomingState *mis);
 int qemu_loadvm_state_main(QEMUFile *f, MigrationIncomingState *mis,
                            Error **errp);

-- 
2.50.0
Re: [PATCH v5 19/23] migration: push Error **errp into qemu_loadvm_state()
Posted by Daniel P. Berrangé 4 months ago
On Thu, Jul 17, 2025 at 06:07:42AM +0530, Arun Menon wrote:
> 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 qemu_loadvm_state() must report an error
> in errp, in case of failure.
> 
> Signed-off-by: Arun Menon <armenon@redhat.com>
> ---
>  migration/migration.c |  5 +++--
>  migration/savevm.c    | 25 +++++++++++++------------
>  migration/savevm.h    |  2 +-
>  3 files changed, 17 insertions(+), 15 deletions(-)


> @@ -3181,8 +3178,12 @@ int qemu_loadvm_state(QEMUFile *f)
>          if (migrate_has_error(migrate_get_current()) ||
>              !qemu_loadvm_thread_pool_wait(s, mis)) {
>              ret = -EINVAL;
> +            error_setg(errp, "Error while loading vmstate : %d", ret);
>          } else {
>              ret = qemu_file_get_error(f);
> +            if (ret < 0) {
> +                error_setg(errp, "Error while loading vmstate : %d", ret);
> +            }

Replace qemu_file_get_error with qemu_file_get_error_obj(..., errp)
so we propagate the real error message.


With regards,
Daniel
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