Hi
On Mon, Jul 21, 2025 at 3:35 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 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 | 45
> ++++++++++++++++++++++++++++-----------------
> tests/unit/test-vmstate.c | 18 +++++++++---------
> ui/vdagent.c | 2 +-
> 15 files changed, 59 insertions(+), 46 deletions(-)
>
> diff --git a/hw/display/virtio-gpu.c b/hw/display/virtio-gpu.c
> index
> 0a1a625b0ea6cf26cb0d799171a57ed3d3ab2442..5d2ca8d8b864350133a674802d7316abd379591c
> 100644
> --- a/hw/display/virtio-gpu.c
> +++ b/hw/display/virtio-gpu.c
> @@ -1343,7 +1343,7 @@ static int virtio_gpu_load(QEMUFile *f, void
> *opaque, size_t size,
> }
>
> /* load & apply scanout state */
> - vmstate_load_state(f, &vmstate_virtio_gpu_scanouts, g, 1);
> + vmstate_load_state(f, &vmstate_virtio_gpu_scanouts, g, 1, NULL);
>
> return 0;
> }
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index
> c70b5ceebaf1f2b10768bd030526cbb518da2b8d..2ab5d30bb3c319ac1c7bfc9a2acf6a2b38082066
> 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -934,7 +934,7 @@ void pci_device_save(PCIDevice *s, QEMUFile *f)
> int pci_device_load(PCIDevice *s, QEMUFile *f)
> {
> int ret;
> - ret = vmstate_load_state(f, &vmstate_pci_device, s, s->version_id);
> + ret = vmstate_load_state(f, &vmstate_pci_device, s, s->version_id,
> NULL);
> /* Restore the interrupt status bit. */
> pci_update_irq_status(s);
> return ret;
> diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
> index
> d2f85b39f30f7fc82e0c600144c0a958e1269b2c..2f6feff2b0a22d7d7f6aecfd7e7870d8362f1a73
> 100644
> --- a/hw/s390x/virtio-ccw.c
> +++ b/hw/s390x/virtio-ccw.c
> @@ -1136,7 +1136,7 @@ static void virtio_ccw_save_config(DeviceState *d,
> QEMUFile *f)
> static int virtio_ccw_load_config(DeviceState *d, QEMUFile *f)
> {
> VirtioCcwDevice *dev = VIRTIO_CCW_DEVICE(d);
> - return vmstate_load_state(f, &vmstate_virtio_ccw_dev, dev, 1);
> + return vmstate_load_state(f, &vmstate_virtio_ccw_dev, dev, 1, NULL);
> }
>
> static void virtio_ccw_pre_plugged(DeviceState *d, Error **errp)
> diff --git a/hw/scsi/spapr_vscsi.c b/hw/scsi/spapr_vscsi.c
> index
> 20f70fb2729de78b9636a6b8c869695dab4f8902..573fdea668536b464bca11f001e9e0288e781493
> 100644
> --- a/hw/scsi/spapr_vscsi.c
> +++ b/hw/scsi/spapr_vscsi.c
> @@ -648,7 +648,7 @@ static void *vscsi_load_request(QEMUFile *f,
> SCSIRequest *sreq)
> assert(!req->active);
>
> memset(req, 0, sizeof(*req));
> - rc = vmstate_load_state(f, &vmstate_spapr_vscsi_req, req, 1);
> + rc = vmstate_load_state(f, &vmstate_spapr_vscsi_req, req, 1, NULL);
> if (rc) {
> fprintf(stderr, "VSCSI: failed loading request tag#%u\n",
> sreq->tag);
> return NULL;
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index
> be05002b9819fafa45cf2fb4d2a0acdc475c558c..f8ce4a40dbe4c070a0d6c111051051ee97542719
> 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -2797,7 +2797,7 @@ static int vfio_pci_load_config(VFIODevice
> *vbasedev, QEMUFile *f)
> old_addr[bar] = pdev->io_regions[bar].addr;
> }
>
> - ret = vmstate_load_state(f, &vmstate_vfio_pci_config, vdev, 1);
> + ret = vmstate_load_state(f, &vmstate_vfio_pci_config, vdev, 1, NULL);
> if (ret) {
> return ret;
> }
> diff --git a/hw/virtio/virtio-mmio.c b/hw/virtio/virtio-mmio.c
> index
> 532c67107ba1d2978a76cf49f9cdc1de1dea3e11..9058b1563462d4464dcba799643a583c93fb5683
> 100644
> --- a/hw/virtio/virtio-mmio.c
> +++ b/hw/virtio/virtio-mmio.c
> @@ -619,7 +619,7 @@ static int virtio_mmio_load_extra_state(DeviceState
> *opaque, QEMUFile *f)
> {
> VirtIOMMIOProxy *proxy = VIRTIO_MMIO(opaque);
>
> - return vmstate_load_state(f, &vmstate_virtio_mmio, proxy, 1);
> + return vmstate_load_state(f, &vmstate_virtio_mmio, proxy, 1, NULL);
> }
>
> static bool virtio_mmio_has_extra_state(DeviceState *opaque)
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index
> 767216d795998708f5716a23ae16c79cd90ff489..f8b52a611e56c22d844fd4cae3619da4f2686d03
> 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -161,7 +161,7 @@ static int virtio_pci_load_extra_state(DeviceState *d,
> QEMUFile *f)
> {
> VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);
>
> - return vmstate_load_state(f, &vmstate_virtio_pci, proxy, 1);
> + return vmstate_load_state(f, &vmstate_virtio_pci, proxy, 1, NULL);
> }
>
> static void virtio_pci_save_queue(DeviceState *d, int n, QEMUFile *f)
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index
> 2ab1d20769495ea39445b87e3673b076ad172510..d5698b062a1e95437f6113f41136e90ae06f1974
> 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -3317,14 +3317,14 @@ virtio_load(VirtIODevice *vdev, QEMUFile *f, int
> version_id)
> }
>
> if (vdc->vmsd) {
> - ret = vmstate_load_state(f, vdc->vmsd, vdev, version_id);
> + ret = vmstate_load_state(f, vdc->vmsd, vdev, version_id, NULL);
> if (ret) {
> return ret;
> }
> }
>
> /* Subsections */
> - ret = vmstate_load_state(f, &vmstate_virtio, vdev, 1);
> + ret = vmstate_load_state(f, &vmstate_virtio, vdev, 1, NULL);
> if (ret) {
> return ret;
> }
> diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
> index
> 1ff7bd9ac425ba67cd5ca7ad97bcf570f9e19abe..056781b1c21e737583f081594d9f88b32adfd674
> 100644
> --- a/include/migration/vmstate.h
> +++ b/include/migration/vmstate.h
> @@ -1196,7 +1196,7 @@ extern const VMStateInfo vmstate_info_qlist;
> }
>
> int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
> - void *opaque, int version_id);
> + void *opaque, int version_id, Error **errp);
> int vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
> void *opaque, JSONWriter *vmdesc);
> int vmstate_save_state_with_err(QEMUFile *f, const VMStateDescription
> *vmsd,
> diff --git a/migration/cpr.c b/migration/cpr.c
> index
> 42ad0b0d500e5de57faf0c6517e216b2d1c0cacf..74fac9521717ec568d14dabcbcb574b19fc1da67
> 100644
> --- a/migration/cpr.c
> +++ b/migration/cpr.c
> @@ -233,9 +233,9 @@ int cpr_state_load(MigrationChannel *channel, Error
> **errp)
> return -ENOTSUP;
> }
>
> - ret = vmstate_load_state(f, &vmstate_cpr_state, &cpr_state, 1);
> + ret = vmstate_load_state(f, &vmstate_cpr_state, &cpr_state, 1, errp);
> if (ret) {
> - error_setg(errp, "vmstate_load_state error %d", ret);
> + error_prepend(errp, "vmstate_load_state error %d ", ret);
>
Although it's not enforced, I think it's recommended to end the
error_prepend() string with ": ", not just a space.
> qemu_fclose(f);
> return ret;
> }
> diff --git a/migration/savevm.c b/migration/savevm.c
> index
> fabbeb296ae987d0c06ba6dafda63720205fecfd..ab947620f724874f325fb9fb59bef50b7c16fb51
> 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -969,7 +969,8 @@ static int vmstate_load(QEMUFile *f, SaveStateEntry
> *se)
> if (!se->vmsd) { /* Old style */
> return se->ops->load_state(f, se->opaque, se->load_version_id);
> }
> - return vmstate_load_state(f, se->vmsd, se->opaque,
> se->load_version_id);
> + return vmstate_load_state(f, se->vmsd, se->opaque,
> se->load_version_id,
> + NULL);
> }
>
> static void vmstate_save_old_style(QEMUFile *f, SaveStateEntry *se,
> @@ -2839,7 +2840,8 @@ static int qemu_loadvm_state_header(QEMUFile *f)
> error_report("Configuration section missing");
> return -EINVAL;
> }
> - ret = vmstate_load_state(f, &vmstate_configuration,
> &savevm_state, 0);
> + ret = vmstate_load_state(f, &vmstate_configuration,
> &savevm_state, 0,
> + NULL);
>
> if (ret) {
> return ret;
> diff --git a/migration/vmstate-types.c b/migration/vmstate-types.c
> index
> 741a588b7e18c6d37724b08a0101edc8bc74a0a5..1c5b76e1dd198030847971bc35637867c9d54fc0
> 100644
> --- a/migration/vmstate-types.c
> +++ b/migration/vmstate-types.c
> @@ -549,7 +549,7 @@ static int get_tmp(QEMUFile *f, void *pv, size_t size,
>
> /* Writes the parent field which is at the start of the tmp */
> *(void **)tmp = pv;
> - ret = vmstate_load_state(f, vmsd, tmp, version_id);
> + ret = vmstate_load_state(f, vmsd, tmp, version_id, NULL);
> g_free(tmp);
> return ret;
> }
> @@ -649,7 +649,7 @@ static int get_qtailq(QEMUFile *f, void *pv, size_t
> unused_size,
>
> while (qemu_get_byte(f)) {
> elm = g_malloc(size);
> - ret = vmstate_load_state(f, vmsd, elm, version_id);
> + ret = vmstate_load_state(f, vmsd, elm, version_id, NULL);
> if (ret) {
> return ret;
> }
> @@ -803,7 +803,7 @@ static int get_gtree(QEMUFile *f, void *pv, size_t
> unused_size,
> key = (void *)(uintptr_t)qemu_get_be64(f);
> } else {
> key = g_malloc0(key_size);
> - ret = vmstate_load_state(f, key_vmsd, key, version_id);
> + ret = vmstate_load_state(f, key_vmsd, key, version_id, NULL);
> if (ret) {
> error_report("%s : failed to load %s (%d)",
> field->name, key_vmsd->name, ret);
> @@ -811,7 +811,7 @@ static int get_gtree(QEMUFile *f, void *pv, size_t
> unused_size,
> }
> }
> val = g_malloc0(val_size);
> - ret = vmstate_load_state(f, val_vmsd, val, version_id);
> + ret = vmstate_load_state(f, val_vmsd, val, version_id, NULL);
> if (ret) {
> error_report("%s : failed to load %s (%d)",
> field->name, val_vmsd->name, ret);
> @@ -892,7 +892,7 @@ static int get_qlist(QEMUFile *f, void *pv, size_t
> unused_size,
>
> while (qemu_get_byte(f)) {
> elm = g_malloc(size);
> - ret = vmstate_load_state(f, vmsd, elm, version_id);
> + ret = vmstate_load_state(f, vmsd, elm, version_id, NULL);
> if (ret) {
> error_report("%s: failed to load %s (%d)", field->name,
> vmsd->name, ret);
> diff --git a/migration/vmstate.c b/migration/vmstate.c
> index
> 129b19d7603a0ddf8ab6e946e41c1c4d773d1fa8..288b57e1ed778cce21247b64d5e97dfef41ad586
> 100644
> --- a/migration/vmstate.c
> +++ b/migration/vmstate.c
> @@ -132,29 +132,33 @@ 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 for: '%s', "
> + "version_id: '%d', minimum version_id: '%d', ret:
> %d",
> + vmsd->name, vmsd->version_id,
> vmsd->minimum_version_id,
> + ret);
> return ret;
> }
> }
> @@ -192,10 +196,12 @@ 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);
> @@ -211,27 +217,32 @@ 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);
> + error_prepend(errp, "Failed to load %s:%s version_id:
> %d ",
> + vmsd->name, field->name,
> vmsd->version_id);
> 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 version_id:
> %d",
> + vmsd->name, field->name, vmsd->version_id);
> 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 for: %s, version_id:
> %d,"
> + "minimum_version: %d, ret: %d", vmsd->name,
> + vmsd->version_id, vmsd->minimum_version_id, ret);
> + }
> }
> trace_vmstate_load_state_end(vmsd->name, "end", ret);
> return ret;
> @@ -607,11 +618,11 @@ static int vmstate_subsection_load(QEMUFile *f,
> const VMStateDescription *vmsd,
> qemu_file_skip(f, len); /* idstr */
> version_id = qemu_get_be32(f);
>
> - ret = vmstate_load_state(f, sub_vmsd, opaque, version_id);
> + ret = vmstate_load_state(f, sub_vmsd, opaque, version_id, errp);
> if (ret) {
> trace_vmstate_subsection_load_bad(vmsd->name, idstr,
> "(child)");
> - error_setg(errp, "Loading VM subsection '%s' in '%s' failed :
> %d",
> - idstr, vmsd->name, ret);
> + error_prepend(errp, "Loading VM subsection '%s'"
> + "in '%s' failed : %d ", idstr, vmsd->name, ret);
> return ret;
> }
> }
> diff --git a/tests/unit/test-vmstate.c b/tests/unit/test-vmstate.c
> index
> 63f28f26f45691a70936d33e7341d16477a3471f..ca5e0ba1e3e5e2bb0a1ce39143a292f2c6f9420a
> 100644
> --- a/tests/unit/test-vmstate.c
> +++ b/tests/unit/test-vmstate.c
> @@ -114,7 +114,7 @@ static int load_vmstate_one(const VMStateDescription
> *desc, void *obj,
> qemu_fclose(f);
>
> f = open_test_file(false);
> - ret = vmstate_load_state(f, desc, obj, version);
> + ret = vmstate_load_state(f, desc, obj, version, NULL);
> if (ret) {
> g_assert(qemu_file_get_error(f));
> } else{
> @@ -365,7 +365,7 @@ static void test_load_v1(void)
>
> QEMUFile *loading = open_test_file(false);
> TestStruct obj = { .b = 200, .e = 500, .f = 600 };
> - vmstate_load_state(loading, &vmstate_versioned, &obj, 1);
> + vmstate_load_state(loading, &vmstate_versioned, &obj, 1, NULL);
> g_assert(!qemu_file_get_error(loading));
> g_assert_cmpint(obj.a, ==, 10);
> g_assert_cmpint(obj.b, ==, 200);
> @@ -391,7 +391,7 @@ static void test_load_v2(void)
>
> QEMUFile *loading = open_test_file(false);
> TestStruct obj;
> - vmstate_load_state(loading, &vmstate_versioned, &obj, 2);
> + vmstate_load_state(loading, &vmstate_versioned, &obj, 2, NULL);
> g_assert_cmpint(obj.a, ==, 10);
> g_assert_cmpint(obj.b, ==, 20);
> g_assert_cmpint(obj.c, ==, 30);
> @@ -480,7 +480,7 @@ static void test_load_noskip(void)
>
> QEMUFile *loading = open_test_file(false);
> TestStruct obj = { .skip_c_e = false };
> - vmstate_load_state(loading, &vmstate_skipping, &obj, 2);
> + vmstate_load_state(loading, &vmstate_skipping, &obj, 2, NULL);
> g_assert(!qemu_file_get_error(loading));
> g_assert_cmpint(obj.a, ==, 10);
> g_assert_cmpint(obj.b, ==, 20);
> @@ -504,7 +504,7 @@ static void test_load_skip(void)
>
> QEMUFile *loading = open_test_file(false);
> TestStruct obj = { .skip_c_e = true, .c = 300, .e = 500 };
> - vmstate_load_state(loading, &vmstate_skipping, &obj, 2);
> + vmstate_load_state(loading, &vmstate_skipping, &obj, 2, NULL);
> g_assert(!qemu_file_get_error(loading));
> g_assert_cmpint(obj.a, ==, 10);
> g_assert_cmpint(obj.b, ==, 20);
> @@ -773,7 +773,7 @@ static void test_load_q(void)
> TestQtailq tgt;
>
> QTAILQ_INIT(&tgt.q);
> - vmstate_load_state(fload, &vmstate_q, &tgt, 1);
> + vmstate_load_state(fload, &vmstate_q, &tgt, 1, NULL);
> char eof = qemu_get_byte(fload);
> g_assert(!qemu_file_get_error(fload));
> g_assert_cmpint(tgt.i16, ==, obj_q.i16);
> @@ -1127,7 +1127,7 @@ static void test_gtree_load_domain(void)
>
> fload = open_test_file(false);
>
> - vmstate_load_state(fload, &vmstate_domain, dest_domain, 1);
> + vmstate_load_state(fload, &vmstate_domain, dest_domain, 1, NULL);
> eof = qemu_get_byte(fload);
> g_assert(!qemu_file_get_error(fload));
> g_assert_cmpint(orig_domain->id, ==, dest_domain->id);
> @@ -1241,7 +1241,7 @@ static void test_gtree_load_iommu(void)
> qemu_fclose(fsave);
>
> fload = open_test_file(false);
> - vmstate_load_state(fload, &vmstate_iommu, dest_iommu, 1);
> + vmstate_load_state(fload, &vmstate_iommu, dest_iommu, 1, NULL);
> eof = qemu_get_byte(fload);
> g_assert(!qemu_file_get_error(fload));
> g_assert_cmpint(orig_iommu->id, ==, dest_iommu->id);
> @@ -1376,7 +1376,7 @@ static void test_load_qlist(void)
> qemu_fclose(fsave);
>
> fload = open_test_file(false);
> - vmstate_load_state(fload, &vmstate_container, dest_container, 1);
> + vmstate_load_state(fload, &vmstate_container, dest_container, 1,
> NULL);
> eof = qemu_get_byte(fload);
> g_assert(!qemu_file_get_error(fload));
> g_assert_cmpint(eof, ==, QEMU_VM_EOF);
> diff --git a/ui/vdagent.c b/ui/vdagent.c
> index
> c0746fe5b168fdc7aeb4866de2ba0c3387566649..83457dee0767433ad0778b37b41b9c673a0e1860
> 100644
> --- a/ui/vdagent.c
> +++ b/ui/vdagent.c
> @@ -1008,7 +1008,7 @@ static int get_cbinfo(QEMUFile *f, void *pv, size_t
> size,
>
> vdagent_clipboard_peer_register(vd);
>
> - ret = vmstate_load_state(f, &vmstate_cbinfo_array, &cbinfo, 0);
> + ret = vmstate_load_state(f, &vmstate_cbinfo_array, &cbinfo, 0, NULL);
> if (ret) {
> return ret;
> }
>
> --
> 2.50.0
>
>
