On Tue, Aug 5, 2025 at 11:03 PM Arun Menon <arme...@redhat.com> 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_section_start_full() must report an error
> in errp, in case of failure.
>
> Signed-off-by: Arun Menon <arme...@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lur...@redhat.com>
> ---
> migration/savevm.c | 36 ++++++++++++++++++++----------------
> 1 file changed, 20 insertions(+), 16 deletions(-)
>
> diff --git a/migration/savevm.c b/migration/savevm.c
> index
> ad3dd9b172afc541f104d2187a79bafa8e380466..e337e3c61e7627f09b853bf5e9b845c38cb5f082
> 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -2722,8 +2722,9 @@ static bool check_section_footer(QEMUFile *f,
> SaveStateEntry *se)
> }
>
> static int
> -qemu_loadvm_section_start_full(QEMUFile *f, uint8_t type)
> +qemu_loadvm_section_start_full(QEMUFile *f, uint8_t type, Error **errp)
> {
> + ERRP_GUARD();
> bool trace_downtime = (type == QEMU_VM_SECTION_FULL);
> uint32_t instance_id, version_id, section_id;
> int64_t start_ts, end_ts;
> @@ -2734,8 +2735,8 @@ qemu_loadvm_section_start_full(QEMUFile *f, uint8_t
> type)
> /* Read section start */
> section_id = qemu_get_be32(f);
> if (!qemu_get_counted_string(f, idstr)) {
> - error_report("Unable to read ID string for section %u",
> - section_id);
> + error_setg(errp, "Unable to read ID string for section %u",
> + section_id);
> return -EINVAL;
> }
> instance_id = qemu_get_be32(f);
> @@ -2743,8 +2744,7 @@ qemu_loadvm_section_start_full(QEMUFile *f, uint8_t
> type)
>
> ret = qemu_file_get_error(f);
> if (ret) {
> - error_report("%s: Failed to read instance/version ID: %d",
> - __func__, ret);
> + error_setg(errp, "Failed to read instance/version ID: %d", ret);
> return ret;
> }
>
> @@ -2753,17 +2753,17 @@ qemu_loadvm_section_start_full(QEMUFile *f, uint8_t
> type)
> /* Find savevm section */
> se = find_se(idstr, instance_id);
> if (se == NULL) {
> - error_report("Unknown savevm section or instance '%s' %"PRIu32". "
> - "Make sure that your current VM setup matches your "
> - "saved VM setup, including any hotplugged devices",
> - idstr, instance_id);
> + error_setg(errp, "Unknown savevm section or instance '%s' %"PRIu32".
> "
> + "Make sure that your current VM setup matches your "
> + "saved VM setup, including any hotplugged devices",
> + idstr, instance_id);
> return -EINVAL;
> }
>
> /* Validate version */
> if (version_id > se->version_id) {
> - error_report("savevm: unsupported version %d for '%s' v%d",
> - version_id, idstr, se->version_id);
> + error_setg(errp, "savevm: unsupported version %d for '%s' v%d",
> + version_id, idstr, se->version_id);
> return -EINVAL;
> }
> se->load_version_id = version_id;
> @@ -2771,7 +2771,7 @@ qemu_loadvm_section_start_full(QEMUFile *f, uint8_t
> type)
>
> /* Validate if it is a device's state */
> if (xen_enabled() && se->is_ram) {
> - error_report("loadvm: %s RAM loading not allowed on Xen", idstr);
> + error_setg(errp, "loadvm: %s RAM loading not allowed on Xen", idstr);
> return -EINVAL;
> }
>
> @@ -2779,10 +2779,11 @@ qemu_loadvm_section_start_full(QEMUFile *f, uint8_t
> type)
> start_ts = qemu_clock_get_us(QEMU_CLOCK_REALTIME);
> }
>
> - ret = vmstate_load(f, se, NULL);
> + ret = vmstate_load(f, se, errp);
> if (ret < 0) {
> - error_report("error while loading state for instance 0x%"PRIx32" of"
> - " device '%s'", instance_id, idstr);
> + error_prepend(errp,
> + "error while loading state for instance 0x%"PRIx32" of"
> + " device '%s': ", instance_id, idstr);
> return ret;
> }
>
> @@ -2793,6 +2794,9 @@ qemu_loadvm_section_start_full(QEMUFile *f, uint8_t
> type)
> }
>
> if (!check_section_footer(f, se)) {
> + error_setg(errp, "Reading footer section of instance "
> + "0x%"PRIx32" of device '%s' for version_id: %d failed",
> + instance_id, idstr, version_id);
> return -EINVAL;
> }
>
> @@ -3097,7 +3101,7 @@ retry:
> switch (section_type) {
> case QEMU_VM_SECTION_START:
> case QEMU_VM_SECTION_FULL:
> - ret = qemu_loadvm_section_start_full(f, section_type);
> + ret = qemu_loadvm_section_start_full(f, section_type, errp);
> if (ret < 0) {
> goto out;
> }
>
> --
> 2.50.1
>
>
--
Marc-André Lureau
