Hi
On Tue, Jun 24, 2025 at 4:26 PM Arun Menon <arme...@redhat.com> wrote:
>
> - Introduce a new post_load_with_error() hook that will
> take in the Error object as a parameter.
You should make this a different patch. I wonder if adding another
callback is the right approach, as only one of the two is called. I
would rather change the existing callback.
> - This error object is set if the loading of state fails.
> - The error can then be retrieved using QMP command
> {"execute" : "query-migrate"}
>
> Buglink: https://issues.redhat.com/browse/RHEL-82826
>
> Signed-off-by: Arun Menon <arme...@redhat.com>
> ---
> backends/tpm/tpm_emulator.c | 39 ++++++++++++++++++++-------------------
> include/migration/vmstate.h | 1 +
> migration/vmstate.c | 4 +++-
> 3 files changed, 24 insertions(+), 20 deletions(-)
>
> diff --git a/backends/tpm/tpm_emulator.c b/backends/tpm/tpm_emulator.c
> index
> 4a234ab2c0b19b2604bf0dd8cb5f4540c72a9438..816134d7b4de00a75a3d0b928d160595b17be810
> 100644
> --- a/backends/tpm/tpm_emulator.c
> +++ b/backends/tpm/tpm_emulator.c
> @@ -819,7 +819,8 @@ static int tpm_emulator_get_state_blobs(TPMEmulator
> *tpm_emu)
> static int tpm_emulator_set_state_blob(TPMEmulator *tpm_emu,
> uint32_t type,
> TPMSizedBuffer *tsb,
> - uint32_t flags)
> + uint32_t flags,
> + Error **errp)
> {
> ssize_t n;
> ptm_setstate pss;
> @@ -838,17 +839,17 @@ static int tpm_emulator_set_state_blob(TPMEmulator
> *tpm_emu,
> /* write the header only */
> if (tpm_emulator_ctrlcmd(tpm_emu, CMD_SET_STATEBLOB, &pss,
> offsetof(ptm_setstate, u.req.data), 0, 0) < 0) {
> - error_report("tpm-emulator: could not set state blob type %d : %s",
> - type, strerror(errno));
> + error_setg(errp, "tpm-emulator: could not set state blob type %d :
> %s",
> + type, strerror(errno));
> return -1;
> }
>
> /* now the body */
> n = qemu_chr_fe_write_all(&tpm_emu->ctrl_chr, tsb->buffer, tsb->size);
> if (n != tsb->size) {
> - error_report("tpm-emulator: Writing the stateblob (type %d) "
> - "failed; could not write %u bytes, but only %zd",
> - type, tsb->size, n);
> + error_setg(errp, "tpm-emulator: Writing the stateblob (type %d) "
> + "failed; could not write %u bytes, but only %zd",
> + type, tsb->size, n);
> return -1;
> }
>
> @@ -856,17 +857,17 @@ static int tpm_emulator_set_state_blob(TPMEmulator
> *tpm_emu,
> n = qemu_chr_fe_read_all(&tpm_emu->ctrl_chr,
> (uint8_t *)&pss, sizeof(pss.u.resp));
> if (n != sizeof(pss.u.resp)) {
> - error_report("tpm-emulator: Reading response from writing stateblob "
> - "(type %d) failed; expected %zu bytes, got %zd", type,
> - sizeof(pss.u.resp), n);
> + error_setg(errp, "tpm-emulator: Reading response from writing "
> + "stateblob (type %d) failed; expected %zu bytes, "
> + "got %zd", type, sizeof(pss.u.resp), n);
> return -1;
> }
>
> tpm_result = be32_to_cpu(pss.u.resp.tpm_result);
> if (tpm_result != 0) {
> - error_report("tpm-emulator: Setting the stateblob (type %d) failed "
> - "with a TPM error 0x%x %s", type, tpm_result,
> - tpm_emulator_strerror(tpm_result));
> + error_setg(errp, "tpm-emulator: Setting the stateblob (type %d) "
> + "failed with a TPM error 0x%x %s", type, tpm_result,
> + tpm_emulator_strerror(tpm_result));
> return -1;
> }
>
> @@ -880,7 +881,7 @@ static int tpm_emulator_set_state_blob(TPMEmulator
> *tpm_emu,
> *
> * Returns a negative errno code in case of error.
> */
> -static int tpm_emulator_set_state_blobs(TPMBackend *tb)
> +static int tpm_emulator_set_state_blobs(TPMBackend *tb, Error **errp)
> {
> TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
> TPMBlobBuffers *state_blobs = &tpm_emu->state_blobs;
> @@ -894,13 +895,13 @@ static int tpm_emulator_set_state_blobs(TPMBackend *tb)
>
> if (tpm_emulator_set_state_blob(tpm_emu, PTM_BLOB_TYPE_PERMANENT,
> &state_blobs->permanent,
> - state_blobs->permanent_flags) < 0 ||
> + state_blobs->permanent_flags, errp) < 0
> ||
> tpm_emulator_set_state_blob(tpm_emu, PTM_BLOB_TYPE_VOLATILE,
> &state_blobs->volatil,
> - state_blobs->volatil_flags) < 0 ||
> + state_blobs->volatil_flags, errp) < 0 ||
> tpm_emulator_set_state_blob(tpm_emu, PTM_BLOB_TYPE_SAVESTATE,
> &state_blobs->savestate,
> - state_blobs->savestate_flags) < 0) {
> + state_blobs->savestate_flags, errp) < 0)
> {
> return -EIO;
> }
>
> @@ -948,12 +949,12 @@ static void tpm_emulator_vm_state_change(void *opaque,
> bool running,
> *
> * Returns negative errno codes in case of error.
> */
> -static int tpm_emulator_post_load(void *opaque, int version_id)
> +static int tpm_emulator_post_load(void *opaque, int version_id, Error **errp)
> {
> TPMBackend *tb = opaque;
> int ret;
>
> - ret = tpm_emulator_set_state_blobs(tb);
> + ret = tpm_emulator_set_state_blobs(tb, errp);
> if (ret < 0) {
> return ret;
> }
> @@ -969,7 +970,7 @@ static const VMStateDescription vmstate_tpm_emulator = {
> .name = "tpm-emulator",
> .version_id = 0,
> .pre_save = tpm_emulator_pre_save,
> - .post_load = tpm_emulator_post_load,
> + .post_load_with_error = tpm_emulator_post_load,
> .fields = (const VMStateField[]) {
> VMSTATE_UINT32(state_blobs.permanent_flags, TPMEmulator),
> VMSTATE_UINT32(state_blobs.permanent.size, TPMEmulator),
> diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
> index
> 056781b1c21e737583f081594d9f88b32adfd674..1c6e89c3b08a3914cde6dce3be5955978b6b7d0b
> 100644
> --- a/include/migration/vmstate.h
> +++ b/include/migration/vmstate.h
> @@ -207,6 +207,7 @@ struct VMStateDescription {
> MigrationPriority priority;
> int (*pre_load)(void *opaque);
> int (*post_load)(void *opaque, int version_id);
> + int (*post_load_with_error)(void *opaque, int version_id, Error **errp);
> int (*pre_save)(void *opaque);
> int (*post_save)(void *opaque);
> bool (*needed)(void *opaque);
> diff --git a/migration/vmstate.c b/migration/vmstate.c
> index
> 3f8c3d3c1dcfe14d70bab1f43b827244eb4bb385..c5dfffd9bad7285e819d4769e055d47157caab34
> 100644
> --- a/migration/vmstate.c
> +++ b/migration/vmstate.c
> @@ -232,7 +232,9 @@ int vmstate_load_state(QEMUFile *f, const
> VMStateDescription *vmsd,
> qemu_file_set_error(f, ret);
> return ret;
> }
> - if (vmsd->post_load) {
> + if (vmsd->post_load_with_error) {
> + ret = vmsd->post_load_with_error(opaque, version_id, errp);
> + } else if (vmsd->post_load) {
> ret = vmsd->post_load(opaque, version_id);
> }
> trace_vmstate_load_state_end(vmsd->name, "end", ret);
>
> --
> 2.49.0
>
>
--
Marc-André Lureau
