migration: introduce vmstate_load_vmsd() and vmstate_save_vmsd()
Introduce new APIs, returning bool. The analysis https://lore.kernel.org/qemu-devel/aQDdRn8t0B8oE3gf@x1.local/ shows, that vmstate_load_state() return value actually only used to check for success, specific errno values doesn't make sense. With this commit we introduce new functions with modern bool interface, and in following commits we'll update the code base to use them, starting from migration/ code, and finally we will remove old vmstate_load_state() and vmstate_save_state(). This patch reworks existing functions to new one, so that old interfaces are simple wrappers, which will be easy to remove later. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Reviewed-by: Peter Xu <peterx@redhat.com> Link: https://lore.kernel.org/qemu-devel/20260304212303.667141-14-vsementsov@yandex-team.ru Signed-off-by: Fabiano Rosas <farosas@suse.de>
Vladimir Sementsov-Ogievskiy committed
Mar 5, 2026 at 00:22 UTC
57036a0cbfda1470018bf5c7f0d98423352a36d9
2 files changed
+58
-40
include/migration/vmstate.h
+9
@@ -1257,10 +1257,19 @@ extern const VMStateInfo vmstate_info_qlist;
1257
.flags = VMS_END, \
1258
}
1259
1260
+/*
1261
+ * vmstate_load_state() and vmstate_save_state() are
1262
+ * depreacated, use vmstate_load_vmsd() and vmstate_save_vmsd()
1263
+ * instead.
1264
+ */
1265
int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
1266
void *opaque, int version_id, Error **errp);
1267
int vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
1268
void *opaque, JSONWriter *vmdesc, Error **errp);
1269
+bool vmstate_load_vmsd(QEMUFile *f, const VMStateDescription *vmsd,
1270
+ void *opaque, int version_id, Error **errp);
1271
+bool vmstate_save_vmsd(QEMUFile *f, const VMStateDescription *vmsd,
1272
+ void *opaque, JSONWriter *vmdesc, Error **errp);
1273
1274
bool vmstate_section_needed(const VMStateDescription *vmsd, void *opaque);
1275
migration/vmstate.c
+49
-40
@@ -26,7 +26,7 @@ static bool vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
26
Error **errp);
27
static bool vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd,
28
void *opaque, Error **errp);
29
-static int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
29
+static bool vmstate_save_vmsd_v(QEMUFile *f, const VMStateDescription *vmsd,
30
void *opaque, JSONWriter *vmdesc,
31
int version_id, Error **errp);
32
@@ -165,11 +165,11 @@ static bool vmstate_load_field(QEMUFile *f, void *pv, size_t size,
165
const VMStateField *field, Error **errp)
166
{
167
if (field->flags & VMS_STRUCT) {
168
- return vmstate_load_state(f, field->vmsd, pv, field->vmsd->version_id,
169
- errp) >= 0;
168
+ return vmstate_load_vmsd(f, field->vmsd, pv, field->vmsd->version_id,
169
+ errp);
170
} else if (field->flags & VMS_VSTRUCT) {
171
- return vmstate_load_state(f, field->vmsd, pv, field->struct_version_id,
172
- errp) >= 0;
171
+ return vmstate_load_vmsd(f, field->vmsd, pv, field->struct_version_id,
172
+ errp);
173
} else if (field->info->load) {
174
return field->info->load(f, pv, size, field, errp);
175
}
@@ -211,12 +211,11 @@ static bool vmstate_post_load(const VMStateDescription *vmsd,
211
return true;
212
}
213
214
-int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
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+bool vmstate_load_vmsd(QEMUFile *f, const VMStateDescription *vmsd,
215
void *opaque, int version_id, Error **errp)
216
{
217
ERRP_GUARD();
218
const VMStateField *field = vmsd->fields;
219
- int ret = 0;
219
220
trace_vmstate_load_state(vmsd->name, version_id);
221
@@ -225,7 +224,7 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
224
"for local version_id %d",
225
vmsd->name, version_id, vmsd->version_id);
226
trace_vmstate_load_state_fail(vmsd->name, "too new");
228
- return -EINVAL;
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+ return false;
228
}
229
230
if (version_id < vmsd->minimum_version_id) {
@@ -233,11 +232,11 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
232
"for local minimum version_id %d",
233
vmsd->name, version_id, vmsd->minimum_version_id);
234
trace_vmstate_load_state_fail(vmsd->name, "too old");
236
- return -EINVAL;
235
+ return false;
236
}
237
238
if (!vmstate_pre_load(vmsd, opaque, errp)) {
240
- return -EINVAL;
239
+ return false;
240
}
241
242
while (field->name) {
@@ -257,6 +256,7 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
256
}
257
258
for (i = 0; i < n_elems; i++) {
259
+ bool ok;
260
void *curr_elem = first_elem + size * i;
261
const VMStateField *inner_field;
262
@@ -275,33 +275,32 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
275
inner_field = field;
276
}
277
278
- ret = vmstate_load_field(f, curr_elem, size, inner_field,
279
- errp) ? 0 : -EINVAL;
278
+ ok = vmstate_load_field(f, curr_elem, size, inner_field, errp);
279
280
/* If we used a fake temp field.. free it now */
281
if (inner_field != field) {
282
g_clear_pointer((gpointer *)&inner_field, g_free);
283
}
284
286
- if (ret >= 0) {
287
- ret = qemu_file_get_error(f);
285
+ if (ok) {
286
+ int ret = qemu_file_get_error(f);
287
if (ret < 0) {
288
error_setg(errp,
289
"Failed to load %s state: stream error: %d",
290
vmsd->name, ret);
291
trace_vmstate_load_field_error(field->name, ret);
293
- return ret;
292
+ return false;
293
}
294
} else {
296
- qemu_file_set_error(f, ret);
297
- trace_vmstate_load_field_error(field->name, ret);
298
- return ret;
295
+ qemu_file_set_error(f, -EINVAL);
296
+ trace_vmstate_load_field_error(field->name, -EINVAL);
297
+ return false;
298
}
299
}
300
} else if (field->flags & VMS_MUST_EXIST) {
301
error_setg(errp, "Input validation failed: %s/%s version_id: %d",
302
vmsd->name, field->name, vmsd->version_id);
304
- return -1;
303
+ return false;
304
}
305
field++;
306
}
@@ -309,17 +308,16 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
308
309
if (!vmstate_subsection_load(f, vmsd, opaque, errp)) {
310
qemu_file_set_error(f, -EINVAL);
312
- return -EINVAL;
311
+ return false;
312
}
313
314
if (!vmstate_post_load(vmsd, opaque, version_id, errp)) {
315
trace_vmstate_load_state_fail(vmsd->name, "post-load");
317
- return -EINVAL;
316
+ return false;
317
}
318
319
trace_vmstate_load_state_success(vmsd->name);
321
-
322
- return 0;
320
+ return true;
321
}
322
323
static int vmfield_name_num(const VMStateField *start,
@@ -492,11 +490,10 @@ static bool vmstate_save_field(QEMUFile *f, void *pv, size_t size,
490
JSONWriter *vmdesc, Error **errp)
491
{
492
if (field->flags & VMS_STRUCT) {
495
- return vmstate_save_state(f, field->vmsd, pv, vmdesc, errp) >= 0;
493
+ return vmstate_save_vmsd(f, field->vmsd, pv, vmdesc, errp);
494
} else if (field->flags & VMS_VSTRUCT) {
497
- return vmstate_save_state_v(f, field->vmsd, pv, vmdesc,
498
- field->struct_version_id,
499
- errp) >= 0;
495
+ return vmstate_save_vmsd_v(f, field->vmsd, pv, vmdesc,
496
+ field->struct_version_id, errp);
497
} else if (field->info->save) {
498
return field->info->save(f, pv, size, field, vmdesc, errp);
499
}
@@ -509,19 +506,19 @@ static bool vmstate_save_field(QEMUFile *f, void *pv, size_t size,
506
return true;
507
}
508
512
-static int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
509
+static bool vmstate_save_vmsd_v(QEMUFile *f, const VMStateDescription *vmsd,
510
void *opaque, JSONWriter *vmdesc,
511
int version_id, Error **errp)
512
{
513
ERRP_GUARD();
517
- int ret = 0;
514
+ bool ok = true;
515
const VMStateField *field = vmsd->fields;
516
517
trace_vmstate_save_state_top(vmsd->name);
518
519
if (!vmstate_pre_save(vmsd, opaque, errp)) {
520
trace_vmstate_save_state_pre_save_fail(vmsd->name);
524
- return -EINVAL;
521
+ return false;
522
}
523
524
trace_vmstate_save_state_pre_save_success(vmsd->name);
@@ -602,8 +599,8 @@ static int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
599
vmsd_desc_field_start(vmsd, vmdesc_loop, inner_field,
600
i, max_elems);
601
605
- ret = vmstate_save_field(f, curr_elem, size, inner_field,
606
- vmdesc_loop, errp) ? 0 : -EINVAL;
602
+ ok = vmstate_save_field(f, curr_elem, size, inner_field,
603
+ vmdesc_loop, errp);
604
605
written_bytes = qemu_file_transferred(f) - old_offset;
606
vmsd_desc_field_end(vmsd, vmdesc_loop, inner_field,
@@ -614,7 +611,7 @@ static int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
611
g_clear_pointer((gpointer *)&inner_field, g_free);
612
}
613
617
- if (ret) {
614
+ if (!ok) {
615
error_prepend(errp, "Save of field %s/%s failed: ",
616
vmsd->name, field->name);
617
goto out;
@@ -640,13 +637,13 @@ static int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
637
json_writer_end_array(vmdesc);
638
}
639
643
- ret = vmstate_subsection_save(f, vmsd, opaque, vmdesc, errp) ? 0 : -EINVAL;
640
+ ok = vmstate_subsection_save(f, vmsd, opaque, vmdesc, errp);
641
642
out:
643
if (vmsd->post_save) {
644
vmsd->post_save(opaque);
645
}
649
- return ret;
646
+ return ok;
647
}
648
649
static const VMStateDescription *
@@ -663,11 +660,11 @@ vmstate_get_subsection(const VMStateDescription * const *sub,
660
return NULL;
661
}
662
666
-int vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
663
+bool vmstate_save_vmsd(QEMUFile *f, const VMStateDescription *vmsd,
664
void *opaque, JSONWriter *vmdesc_id, Error **errp)
665
{
669
- return vmstate_save_state_v(f, vmsd, opaque, vmdesc_id, vmsd->version_id,
670
- errp);
666
+ return vmstate_save_vmsd_v(f, vmsd, opaque, vmdesc_id, vmsd->version_id,
667
+ errp);
668
}
669
670
static bool vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd,
@@ -712,7 +709,7 @@ static bool vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd,
709
qemu_file_skip(f, len); /* idstr */
710
version_id = qemu_get_be32(f);
711
715
- if (vmstate_load_state(f, sub_vmsd, opaque, version_id, errp) < 0) {
712
+ if (!vmstate_load_vmsd(f, sub_vmsd, opaque, version_id, errp)) {
713
trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(child)");
714
error_prepend(errp,
715
"Loading VM subsection '%s' in '%s' failed: ",
@@ -754,7 +751,7 @@ static bool vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
751
qemu_put_byte(f, len);
752
qemu_put_buffer(f, (uint8_t *)vmsdsub->name, len);
753
qemu_put_be32(f, vmsdsub->version_id);
757
- if (vmstate_save_state(f, vmsdsub, opaque, vmdesc, errp) < 0) {
754
+ if (!vmstate_save_vmsd(f, vmsdsub, opaque, vmdesc, errp)) {
755
return false;
756
}
757
@@ -771,3 +768,15 @@ static bool vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
768
769
return true;
770
}
771
+
772
+int vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
773
+ void *opaque, JSONWriter *vmdesc_id, Error **errp)
774
+{
775
+ return vmstate_save_vmsd(f, vmsd, opaque, vmdesc_id, errp) ? 0 : -EINVAL;
776
+}
777
+
778
+int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
779
+ void *opaque, int version_id, Error **errp)
780
+{
781
+ return vmstate_load_vmsd(f, vmsd, opaque, version_id, errp) ? 0 : -EINVAL;
782
+}