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);
> +
> 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.
> +
> + 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()?
> +{
> + 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..
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);
}
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
>
--
Peter Xu
