Hi Daniel,
Thank you so much for the review.
On Thu, Jul 17, 2025 at 05:32:14PM +0100, Daniel P. Berrangé wrote:
> On Thu, Jul 17, 2025 at 06:07:25AM +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 vmstate_load_state() must report an error
> > in errp, in case of failure.
> >
> > Signed-off-by: Arun Menon <arme...@redhat.com>
> > ---
> > hw/display/virtio-gpu.c | 2 +-
> > hw/pci/pci.c | 2 +-
> > hw/s390x/virtio-ccw.c | 2 +-
> > hw/scsi/spapr_vscsi.c | 2 +-
> > hw/vfio/pci.c | 2 +-
> > hw/virtio/virtio-mmio.c | 2 +-
> > hw/virtio/virtio-pci.c | 2 +-
> > hw/virtio/virtio.c | 4 ++--
> > include/migration/vmstate.h | 2 +-
> > migration/cpr.c | 4 ++--
> > migration/savevm.c | 6 ++++--
> > migration/vmstate-types.c | 10 +++++-----
> > migration/vmstate.c | 43
> > +++++++++++++++++++++++++++----------------
> > tests/unit/test-vmstate.c | 18 +++++++++---------
> > ui/vdagent.c | 2 +-
> > 15 files changed, 58 insertions(+), 45 deletions(-)
> >
>
> > diff --git a/migration/vmstate.c b/migration/vmstate.c
> > index
> > 526668a020562f303d2ddf030b1c8466659b67be..078a00003023cc248fb16f05017d4c4251fd86df
> > 100644
> > --- a/migration/vmstate.c
> > +++ b/migration/vmstate.c
> > @@ -132,29 +132,30 @@ static void vmstate_handle_alloc(void *ptr, const
> > VMStateField *field,
> > }
> >
> > int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
> > - void *opaque, int version_id)
> > + void *opaque, int version_id, Error **errp)
> > {
> > const VMStateField *field = vmsd->fields;
> > int ret = 0;
> >
> > trace_vmstate_load_state(vmsd->name, version_id);
> > if (version_id > vmsd->version_id) {
> > - error_report("%s: incoming version_id %d is too new "
> > - "for local version_id %d",
> > - vmsd->name, version_id, vmsd->version_id);
> > + error_setg(errp, "%s: incoming version_id %d is too new "
> > + "for local version_id %d",
> > + vmsd->name, version_id, vmsd->version_id);
> > trace_vmstate_load_state_end(vmsd->name, "too new", -EINVAL);
> > return -EINVAL;
> > }
> > if (version_id < vmsd->minimum_version_id) {
> > - error_report("%s: incoming version_id %d is too old "
> > - "for local minimum version_id %d",
> > - vmsd->name, version_id, vmsd->minimum_version_id);
> > + error_setg(errp, "%s: incoming version_id %d is too old "
> > + "for local minimum version_id %d",
> > + vmsd->name, version_id, vmsd->minimum_version_id);
> > trace_vmstate_load_state_end(vmsd->name, "too old", -EINVAL);
> > return -EINVAL;
> > }
> > if (vmsd->pre_load) {
> > ret = vmsd->pre_load(opaque);
> > if (ret) {
> > + error_setg(errp, "VM pre load failed : %d", ret);
>
> Suggest including
>
> vmsd->name, version_id, vmsd->minimum_version_id
>
> as those are all relevant context which may aid in diagnosing
> this error.
>
> > return ret;
> > }
> > }
> > @@ -192,10 +193,12 @@ int vmstate_load_state(QEMUFile *f, const
> > VMStateDescription *vmsd,
> >
> > if (inner_field->flags & VMS_STRUCT) {
> > ret = vmstate_load_state(f, inner_field->vmsd,
> > curr_elem,
> > -
> > inner_field->vmsd->version_id);
> > + inner_field->vmsd->version_id,
> > + errp);
> > } else if (inner_field->flags & VMS_VSTRUCT) {
> > ret = vmstate_load_state(f, inner_field->vmsd,
> > curr_elem,
> > -
> > inner_field->struct_version_id);
> > +
> > inner_field->struct_version_id,
> > + errp);
> > } else {
> > ret = inner_field->info->get(f, curr_elem, size,
> > inner_field);
>
> This should have the "error_setg" call, so...
About this. I saw few 'get' functions that does not have error_setg() call,
for example vhost_user_net_load_state() or get_fpscr() function calls.
I was not sure, therefore I covered both the cases.
Now I think they do satisfy the if/else if clauses.
Please correct me if I am wrong.
>
> > @@ -211,27 +214,35 @@ int vmstate_load_state(QEMUFile *f, const
> > VMStateDescription *vmsd,
> > }
> > if (ret < 0) {
> > qemu_file_set_error(f, ret);
> > - error_report("Failed to load %s:%s", vmsd->name,
> > - field->name);
> > + if (errp != NULL) {
> > + error_prepend(errp, "Failed to load %s:%s ",
> > vmsd->name,
> > + field->name);
> > + } else {
> > + error_setg(errp, "Failed to load %s:%s",
> > vmsd->name,
> > + field->name);
> > + }
>
> ...this should exclusively do error_prepend.
>
> Also include the 'version_id' here as an bit of extra context.
Yes.
>
> > trace_vmstate_load_field_error(field->name, ret);
> > return ret;
> > }
> > }
> > } else if (field->flags & VMS_MUST_EXIST) {
> > - error_report("Input validation failed: %s/%s",
> > - vmsd->name, field->name);
> > + error_setg(errp, "Input validation failed: %s/%s",
> > + vmsd->name, field->name);
>
>
> Inlucde the version_id too
Yes.
>
> > return -1;
> > }
> > field++;
> > }
> > assert(field->flags == VMS_END);
> > - ret = vmstate_subsection_load(f, vmsd, opaque, NULL);
> > + ret = vmstate_subsection_load(f, vmsd, opaque, errp);
> > if (ret != 0) {
> > qemu_file_set_error(f, ret);
> > return ret;
> > }
> > if (vmsd->post_load) {
> > ret = vmsd->post_load(opaque, version_id);
> > + if (ret < 0) {
> > + error_setg(errp, "VM Post load failed : %d", ret);
> > + }
>
> Suggest including
>
> vmsd->name, version_id, vmsd->minimum_version_id
Agreed.
>
>
> > }
> > trace_vmstate_load_state_end(vmsd->name, "end", ret);
> > return ret;
>
>
>
> With regards,
> Daniel
> --
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>
Regards,
Arun
