Peter Xu <pet...@redhat.com> writes:
> On Mon, Jun 02, 2025 at 10:37:50PM -0300, Fabiano Rosas wrote:
>> The migration parameters tls_creds, tls_authz and tls_hostname
>> currently have a non-uniform handling. When used as arguments to
>> migrate-set-parameters, their type is StrOrNull and when used as
>> return value from query-migrate-parameters, their type is a plain
>> string.
>>
>> Not only having to convert between the types is cumbersome, but it
>> also creates the issue of requiring two different QAPI types to be
>> used, one for each command. MigrateSetParameters is used for
>> migrate-set-parameters with the TLS arguments as StrOrNull while
>> MigrationParameters is used for query-migrate-parameters with the TLS
>> arguments as str.
>>
>> Since StrOrNull could be considered a superset of str, change the type
>> of the TLS arguments in MigrationParameters to StrOrNull and add a
>> helper to ensure they're never actually used as QTYPE_QNULL.
>>
>> This will allow the type duplication to be removed in the next
>> patches.
>
> Definitely a progress if we can finally merge the two!
>
>>
>> Signed-off-by: Fabiano Rosas <faro...@suse.de>
>> ---
>> migration/migration-hmp-cmds.c | 8 +-
>> migration/migration.c | 2 +
>> migration/options.c | 149 ++++++++++++++++++++-------------
>> migration/options.h | 1 +
>> migration/tls.c | 2 +-
>> qapi/migration.json | 6 +-
>> 6 files changed, 99 insertions(+), 69 deletions(-)
>>
>> diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c
>> index e8a563c7d8..bc8179c582 100644
>> --- a/migration/migration-hmp-cmds.c
>> +++ b/migration/migration-hmp-cmds.c
>> @@ -276,14 +276,12 @@ void hmp_info_migrate_parameters(Monitor *mon, const
>> QDict *qdict)
>> monitor_printf(mon, "%s: %u\n",
>> MigrationParameter_str(MIGRATION_PARAMETER_MAX_CPU_THROTTLE),
>> params->max_cpu_throttle);
>> - assert(params->tls_creds);
>> monitor_printf(mon, "%s: '%s'\n",
>> MigrationParameter_str(MIGRATION_PARAMETER_TLS_CREDS),
>> - params->tls_creds);
>> - assert(params->tls_hostname);
>> + params->tls_creds ? params->tls_creds->u.s : "");
>> monitor_printf(mon, "%s: '%s'\n",
>> MigrationParameter_str(MIGRATION_PARAMETER_TLS_HOSTNAME),
>> - params->tls_hostname);
>> + params->tls_hostname ? params->tls_hostname->u.s :
>> "");
>> assert(params->has_max_bandwidth);
>> monitor_printf(mon, "%s: %" PRIu64 " bytes/second\n",
>> MigrationParameter_str(MIGRATION_PARAMETER_MAX_BANDWIDTH),
>> @@ -319,7 +317,7 @@ void hmp_info_migrate_parameters(Monitor *mon, const
>> QDict *qdict)
>> params->max_postcopy_bandwidth);
>> monitor_printf(mon, "%s: '%s'\n",
>> MigrationParameter_str(MIGRATION_PARAMETER_TLS_AUTHZ),
>> - params->tls_authz);
>> + params->tls_authz ? params->tls_authz->u.s : "");
>>
>> if (params->has_block_bitmap_mapping) {
>> const BitmapMigrationNodeAliasList *bmnal;
>> diff --git a/migration/migration.c b/migration/migration.c
>> index 4697732bef..f65cb81b6d 100644
>> --- a/migration/migration.c
>> +++ b/migration/migration.c
>> @@ -4053,6 +4053,8 @@ static void migration_instance_finalize(Object *obj)
>> {
>> MigrationState *ms = MIGRATION_OBJ(obj);
>>
>> + migrate_tls_opts_free(&ms->parameters);
>
> Does this line imply that maybe it's time we make MigrationState.parameters
> a pointer instead of embeded struct anymore?
>
> We already used to have tls_* strings hence that idea should be already
> applicable even before.. but this work just made me think about it more.
>
> So instead of freeing sub-fields if we add more to MigrationParameters, we
> could then do:
>
> g_clear_pointer(&ms->parameters, qapi_free_MigrationParameters);
>
I don't see why not. I can add a patch at the end doing the conversion
globally.
>> +
>> qemu_mutex_destroy(&ms->error_mutex);
>> qemu_mutex_destroy(&ms->qemu_file_lock);
>> qemu_sem_destroy(&ms->wait_unplug_sem);
>> diff --git a/migration/options.c b/migration/options.c
>> index 162c72cda4..45a95dc6da 100644
>> --- a/migration/options.c
>> +++ b/migration/options.c
>> @@ -162,9 +162,11 @@ const Property migration_properties[] = {
>> DEFINE_PROP_SIZE("announce-step", MigrationState,
>> parameters.announce_step,
>> DEFAULT_MIGRATE_ANNOUNCE_STEP),
>> - DEFINE_PROP_STRING("tls-creds", MigrationState, parameters.tls_creds),
>> - DEFINE_PROP_STRING("tls-hostname", MigrationState,
>> parameters.tls_hostname),
>> - DEFINE_PROP_STRING("tls-authz", MigrationState, parameters.tls_authz),
>> + /*
>> + * tls-creds, tls-hostname and tls-authz are of type StrOrNull,
>> + * which can't be easily handled (if at all) by qdev. So these
>> + * will not be exposed as global migration options (-global).
>> + */
>> DEFINE_PROP_UINT64("x-vcpu-dirty-limit-period", MigrationState,
>> parameters.x_vcpu_dirty_limit_period,
>> DEFAULT_MIGRATE_VCPU_DIRTY_LIMIT_PERIOD),
>> @@ -379,13 +381,6 @@ bool migrate_rdma(void)
>> return s->rdma_migration;
>> }
>>
>> -bool migrate_tls(void)
>> -{
>> - MigrationState *s = migrate_get_current();
>> -
>> - return s->parameters.tls_creds && *s->parameters.tls_creds;
>> -}
>> -
>> typedef enum WriteTrackingSupport {
>> WT_SUPPORT_UNKNOWN = 0,
>> WT_SUPPORT_ABSENT,
>> @@ -834,21 +829,44 @@ const char *migrate_tls_authz(void)
>> {
>> MigrationState *s = migrate_get_current();
>>
>> - return s->parameters.tls_authz;
>> + if (s->parameters.tls_authz &&
>> + s->parameters.tls_authz->type == QTYPE_QSTRING &&
>> + *s->parameters.tls_authz->u.s) {
>> + return s->parameters.tls_authz->u.s;
>> + }
>
> Nitpick: some deduplication would be nice? E.g.
>
> bool StrOrNull_str_valid(StrOrNull *obj)
> {
> return obj && obj->type == QTYPE_QSTRING && *obj->u.s;
> }
>
> const char *StrOrNull_str_get(StrOrNull *obj)
> {
> assert(obj && obj->type == QTYPE_QSTRING);
> return obj->u.s;
> }
>
> const char *StrOrNull_to_str(StrOrNull *obj)
> {
> return StrOrNull_str_valid(obj) ? StrOrNull_str_get(obj) : NULL;
> }
>
> Then:
>
> const char *migrate_tls_authz(void)
> {
> return StrOrNull_to_str(s->parameters.tls_authz);
> }
>
> Then apply below.
>
Sure.
>> +
>> + return NULL;
>> }
>>
>> const char *migrate_tls_creds(void)
>> {
>> MigrationState *s = migrate_get_current();
>>
>> - return s->parameters.tls_creds;
>> + if (s->parameters.tls_creds &&
>> + s->parameters.tls_creds->type == QTYPE_QSTRING &&
>> + *s->parameters.tls_creds->u.s) {
>> + return s->parameters.tls_creds->u.s;
>> + }
>> +
>> + return NULL;
>> }
>>
>> const char *migrate_tls_hostname(void)
>> {
>> MigrationState *s = migrate_get_current();
>>
>> - return s->parameters.tls_hostname;
>> + if (s->parameters.tls_hostname &&
>> + s->parameters.tls_hostname->type == QTYPE_QSTRING &&
>> + *s->parameters.tls_hostname->u.s) {
>> + return s->parameters.tls_hostname->u.s;
>> + }
>> +
>> + return NULL;
>> +}
>> +
>> +bool migrate_tls(void)
>> +{
>> + return !!migrate_tls_creds();
>> }
>>
>> uint64_t migrate_vcpu_dirty_limit_period(void)
>> @@ -888,6 +906,36 @@ AnnounceParameters *migrate_announce_params(void)
>> return ≈
>> }
>>
>> +void migrate_tls_opts_free(MigrationParameters *params)
>> +{
>> + qapi_free_StrOrNull(params->tls_creds);
>> + qapi_free_StrOrNull(params->tls_hostname);
>> + qapi_free_StrOrNull(params->tls_authz);
>> +}
>> +
>> +/* needs BQL if dst is part of s->parameters */
>> +static void tls_option_set_str(StrOrNull **dstp, StrOrNull *src)
>
> Nitpick: set_str made me think that the internal objects will be stolen.
> Maybe tls_option_copy()?
>
Yeah, the idea was "set the TLS option and make sure it's a string".
>> +{
>> + StrOrNull *dst = *dstp;
>> +
>> + assert(!dst);
>> +
>> + dst = *dstp = g_new0(StrOrNull, 1);
>> + dst->type = QTYPE_QSTRING;
>> +
>> + if (!src) {
>> + dst->u.s = g_strdup("");
>> + return;
>> + }
>> +
>> + if (src->type == QTYPE_QSTRING) {
>> + dst->u.s = g_strdup(src->u.s);
>> + } else {
>> + assert(src->type == QTYPE_QNULL);
>> + dst->u.s = g_strdup("");
>> + }
>> +}
>> +
>> MigrationParameters *qmp_query_migrate_parameters(Error **errp)
>> {
>> MigrationParameters *params;
>> @@ -903,10 +951,11 @@ MigrationParameters
>> *qmp_query_migrate_parameters(Error **errp)
>> params->cpu_throttle_increment = s->parameters.cpu_throttle_increment;
>> params->has_cpu_throttle_tailslow = true;
>> params->cpu_throttle_tailslow = s->parameters.cpu_throttle_tailslow;
>> - params->tls_creds = g_strdup(s->parameters.tls_creds);
>> - params->tls_hostname = g_strdup(s->parameters.tls_hostname);
>> - params->tls_authz = g_strdup(s->parameters.tls_authz ?
>> - s->parameters.tls_authz : "");
>> +
>> + tls_option_set_str(¶ms->tls_creds, s->parameters.tls_creds);
>> + tls_option_set_str(¶ms->tls_hostname, s->parameters.tls_hostname);
>> + tls_option_set_str(¶ms->tls_authz, s->parameters.tls_authz);
>> +
>> params->has_max_bandwidth = true;
>> params->max_bandwidth = s->parameters.max_bandwidth;
>> params->has_avail_switchover_bandwidth = true;
>> @@ -963,9 +1012,6 @@ MigrationParameters *qmp_query_migrate_parameters(Error
>> **errp)
>>
>> void migrate_params_init(MigrationParameters *params)
>> {
>> - params->tls_hostname = g_strdup("");
>> - params->tls_creds = g_strdup("");
>> -
>> /* Set has_* up only for parameter checks */
>> params->has_throttle_trigger_threshold = true;
>> params->has_cpu_throttle_initial = true;
>> @@ -1142,7 +1188,8 @@ bool migrate_params_check(MigrationParameters *params,
>> Error **errp)
>> #ifdef CONFIG_LINUX
>> if (migrate_zero_copy_send() &&
>> ((params->has_multifd_compression && params->multifd_compression) ||
>> - (params->tls_creds && *params->tls_creds))) {
>> + (params->tls_creds && params->tls_creds->type == QTYPE_QSTRING &&
>> + *params->tls_creds->u.s))) {
>
> Nitpick: StrOrNull_str_valid() candidate.
>
>> error_setg(errp,
>> "Zero copy only available for non-compressed non-TLS
>> multifd migration");
>> return false;
>> @@ -1204,18 +1251,24 @@ static void
>> migrate_params_test_apply(MigrateSetParameters *params,
>> }
>>
>> if (params->tls_creds) {
>> - assert(params->tls_creds->type == QTYPE_QSTRING);
>> - dest->tls_creds = params->tls_creds->u.s;
>> + tls_option_set_str(&dest->tls_creds, params->tls_creds);
>> + } else {
>> + /* drop the reference, it's owned by s->parameters */
>> + dest->tls_creds = NULL;
>> }
>
> This looks ok, but smells tricky, because before this line, "params" can
> contain something that it doesn't own..
>
This else actually goes away in patch 11. I'm taking small steps to get
there to make the diffs easier to review.
> If above idea of "making MigrationState->parameters a real QAPI object"
> works out, here IIUC we can also make "params" a real QAPI object by
> QAPI_CLONE(MigrationState->parameters), then when reaching here:
>
> if (params->tls_creds) {
> qapi_free_StrOrNull(params->tls_creds);
> params->tls_creds = QAPI_CLONE(params->tls_creds);
> }
>
Patches 10-13 clean this situation up and use QAPI_CLONE* all over.
> It avoids the tricky "else" where we need to remember to clear something it
> doesn't ever own. Same to the rest.
>
>>
>> if (params->tls_hostname) {
>> - assert(params->tls_hostname->type == QTYPE_QSTRING);
>> - dest->tls_hostname = params->tls_hostname->u.s;
>> + tls_option_set_str(&dest->tls_hostname, params->tls_hostname);
>> + } else {
>> + /* drop the reference, it's owned by s->parameters */
>> + dest->tls_hostname = NULL;
>> }
>>
>> if (params->tls_authz) {
>> - assert(params->tls_authz->type == QTYPE_QSTRING);
>> - dest->tls_authz = params->tls_authz->u.s;
>> + tls_option_set_str(&dest->tls_authz, params->tls_authz);
>> + } else {
>> + /* drop the reference, it's owned by s->parameters */
>> + dest->tls_authz = NULL;
>> }
>>
>> if (params->has_max_bandwidth) {
>> @@ -1320,21 +1373,18 @@ static void
>> migrate_params_apply(MigrateSetParameters *params, Error **errp)
>> }
>>
>> if (params->tls_creds) {
>> - g_free(s->parameters.tls_creds);
>> - assert(params->tls_creds->type == QTYPE_QSTRING);
>> - s->parameters.tls_creds = g_strdup(params->tls_creds->u.s);
>> + qapi_free_StrOrNull(s->parameters.tls_creds);
>> + tls_option_set_str(&s->parameters.tls_creds, params->tls_creds);
>
> Yeah, exactly like this one..
>
>> }
>>
>> if (params->tls_hostname) {
>> - g_free(s->parameters.tls_hostname);
>> - assert(params->tls_hostname->type == QTYPE_QSTRING);
>> - s->parameters.tls_hostname = g_strdup(params->tls_hostname->u.s);
>> + qapi_free_StrOrNull(s->parameters.tls_hostname);
>> + tls_option_set_str(&s->parameters.tls_hostname,
>> params->tls_hostname);
>> }
>>
>> if (params->tls_authz) {
>> - g_free(s->parameters.tls_authz);
>> - assert(params->tls_authz->type == QTYPE_QSTRING);
>> - s->parameters.tls_authz = g_strdup(params->tls_authz->u.s);
>> + qapi_free_StrOrNull(s->parameters.tls_authz);
>> + tls_option_set_str(&s->parameters.tls_authz, params->tls_authz);
>> }
>>
>> if (params->has_max_bandwidth) {
>> @@ -1433,32 +1483,11 @@ void qmp_migrate_set_parameters(MigrateSetParameters
>> *params, Error **errp)
>> {
>> MigrationParameters tmp;
>>
>> - /* TODO Rewrite "" to null instead for all three tls_* parameters */
>> - if (params->tls_creds
>> - && params->tls_creds->type == QTYPE_QNULL) {
>> - qobject_unref(params->tls_creds->u.n);
>> - params->tls_creds->type = QTYPE_QSTRING;
>> - params->tls_creds->u.s = strdup("");
>> - }
>> - if (params->tls_hostname
>> - && params->tls_hostname->type == QTYPE_QNULL) {
>> - qobject_unref(params->tls_hostname->u.n);
>> - params->tls_hostname->type = QTYPE_QSTRING;
>> - params->tls_hostname->u.s = strdup("");
>> - }
>> - if (params->tls_authz
>> - && params->tls_authz->type == QTYPE_QNULL) {
>> - qobject_unref(params->tls_authz->u.n);
>> - params->tls_authz->type = QTYPE_QSTRING;
>> - params->tls_authz->u.s = strdup("");
>> - }
>> -
>> migrate_params_test_apply(params, &tmp);
>>
>> - if (!migrate_params_check(&tmp, errp)) {
>> - /* Invalid parameter */
>> - return;
>> + if (migrate_params_check(&tmp, errp)) {
>> + migrate_params_apply(params, errp);
>> }
>>
>> - migrate_params_apply(params, errp);
>> + migrate_tls_opts_free(&tmp);
>> }
>> diff --git a/migration/options.h b/migration/options.h
>> index 82d839709e..999eee6f3b 100644
>> --- a/migration/options.h
>> +++ b/migration/options.h
>> @@ -91,4 +91,5 @@ ZeroPageDetection migrate_zero_page_detection(void);
>>
>> bool migrate_params_check(MigrationParameters *params, Error **errp);
>> void migrate_params_init(MigrationParameters *params);
>> +void migrate_tls_opts_free(MigrationParameters *params);
>> #endif
>> diff --git a/migration/tls.c b/migration/tls.c
>> index 5cbf952383..8a89d3f767 100644
>> --- a/migration/tls.c
>> +++ b/migration/tls.c
>> @@ -126,7 +126,7 @@ QIOChannelTLS *migration_tls_client_create(QIOChannel
>> *ioc,
>> }
>>
>> const char *tls_hostname = migrate_tls_hostname();
>> - if (tls_hostname && *tls_hostname) {
>> + if (tls_hostname) {
>> hostname = tls_hostname;
>> }
>>
>> diff --git a/qapi/migration.json b/qapi/migration.json
>> index 41826bde45..fa42d94810 100644
>> --- a/qapi/migration.json
>> +++ b/qapi/migration.json
>> @@ -1293,9 +1293,9 @@
>> '*cpu-throttle-initial': 'uint8',
>> '*cpu-throttle-increment': 'uint8',
>> '*cpu-throttle-tailslow': 'bool',
>> - '*tls-creds': 'str',
>> - '*tls-hostname': 'str',
>> - '*tls-authz': 'str',
>> + '*tls-creds': 'StrOrNull',
>> + '*tls-hostname': 'StrOrNull',
>> + '*tls-authz': 'StrOrNull',
>> '*max-bandwidth': 'size',
>> '*avail-switchover-bandwidth': 'size',
>> '*downtime-limit': 'uint64',
>> --
>> 2.35.3
>>
