Peter Xu <pet...@redhat.com> writes:
> On Mon, Jun 30, 2025 at 04:59:02PM -0300, Fabiano Rosas wrote:
>> Instead of setting parameters one by one, use the temporary object,
>> which already contains the current migration parameters plus the new
>> ones and was just validated by migration_params_check(). Use cloning
>> to overwrite it.
>>
>> This avoids the need to alter this function every time a new parameter
>> is added.
>>
>> Signed-off-by: Fabiano Rosas <faro...@suse.de>
>> ---
>> migration/options.c | 123 +++-----------------------------------------
>> 1 file changed, 7 insertions(+), 116 deletions(-)
>>
>> diff --git a/migration/options.c b/migration/options.c
>> index 4564db77f2..6619b5f21a 100644
>> --- a/migration/options.c
>> +++ b/migration/options.c
>> @@ -13,6 +13,7 @@
>>
>> #include "qemu/osdep.h"
>> #include "qemu/error-report.h"
>> +#include "qemu/main-loop.h"
>> #include "exec/target_page.h"
>> #include "qapi/clone-visitor.h"
>> #include "qapi/error.h"
>> @@ -1341,123 +1342,13 @@ static void
>> migrate_params_test_apply(MigrationParameters *params,
>> static void migrate_params_apply(MigrationParameters *params)
>> {
>> MigrationState *s = migrate_get_current();
>> + MigrationParameters *cur = &s->parameters;
>>
>> - /* TODO use QAPI_CLONE() instead of duplicating it inline */
>> + assert(bql_locked());
>>
>> - if (params->has_throttle_trigger_threshold) {
>> - s->parameters.throttle_trigger_threshold =
>> params->throttle_trigger_threshold;
>> - }
>> -
>> - if (params->has_cpu_throttle_initial) {
>> - s->parameters.cpu_throttle_initial = params->cpu_throttle_initial;
>> - }
>> -
>> - if (params->has_cpu_throttle_increment) {
>> - s->parameters.cpu_throttle_increment =
>> params->cpu_throttle_increment;
>> - }
>> -
>> - if (params->has_cpu_throttle_tailslow) {
>> - s->parameters.cpu_throttle_tailslow = params->cpu_throttle_tailslow;
>> - }
>> -
>> - if (params->tls_creds) {
>> - qapi_free_StrOrNull(s->parameters.tls_creds);
>> - s->parameters.tls_creds = QAPI_CLONE(StrOrNull, params->tls_creds);
>> - }
>> -
>> - if (params->tls_hostname) {
>> - qapi_free_StrOrNull(s->parameters.tls_hostname);
>> - s->parameters.tls_hostname = QAPI_CLONE(StrOrNull,
>> - params->tls_hostname);
>> - }
>> -
>> - if (params->tls_authz) {
>> - qapi_free_StrOrNull(s->parameters.tls_authz);
>> - s->parameters.tls_authz = QAPI_CLONE(StrOrNull, params->tls_authz);
>> - }
>> -
>> - if (params->has_max_bandwidth) {
>> - s->parameters.max_bandwidth = params->max_bandwidth;
>> - }
>> -
>> - if (params->has_avail_switchover_bandwidth) {
>> - s->parameters.avail_switchover_bandwidth =
>> params->avail_switchover_bandwidth;
>> - }
>> -
>> - if (params->has_downtime_limit) {
>> - s->parameters.downtime_limit = params->downtime_limit;
>> - }
>> -
>> - if (params->has_x_checkpoint_delay) {
>> - s->parameters.x_checkpoint_delay = params->x_checkpoint_delay;
>> - }
>> -
>> - if (params->has_multifd_channels) {
>> - s->parameters.multifd_channels = params->multifd_channels;
>> - }
>> - if (params->has_multifd_compression) {
>> - s->parameters.multifd_compression = params->multifd_compression;
>> - }
>> - if (params->has_multifd_qatzip_level) {
>> - s->parameters.multifd_qatzip_level = params->multifd_qatzip_level;
>> - }
>> - if (params->has_multifd_zlib_level) {
>> - s->parameters.multifd_zlib_level = params->multifd_zlib_level;
>> - }
>> - if (params->has_multifd_zstd_level) {
>> - s->parameters.multifd_zstd_level = params->multifd_zstd_level;
>> - }
>> - if (params->has_xbzrle_cache_size) {
>> - s->parameters.xbzrle_cache_size = params->xbzrle_cache_size;
>> - }
>> - if (params->has_max_postcopy_bandwidth) {
>> - s->parameters.max_postcopy_bandwidth =
>> params->max_postcopy_bandwidth;
>> - }
>> - if (params->has_max_cpu_throttle) {
>> - s->parameters.max_cpu_throttle = params->max_cpu_throttle;
>> - }
>> - if (params->has_announce_initial) {
>> - s->parameters.announce_initial = params->announce_initial;
>> - }
>> - if (params->has_announce_max) {
>> - s->parameters.announce_max = params->announce_max;
>> - }
>> - if (params->has_announce_rounds) {
>> - s->parameters.announce_rounds = params->announce_rounds;
>> - }
>> - if (params->has_announce_step) {
>> - s->parameters.announce_step = params->announce_step;
>> - }
>> -
>> - if (params->has_block_bitmap_mapping) {
>> - qapi_free_BitmapMigrationNodeAliasList(
>> - s->parameters.block_bitmap_mapping);
>> -
>> - s->has_block_bitmap_mapping = true;
>> - s->parameters.block_bitmap_mapping =
>> - QAPI_CLONE(BitmapMigrationNodeAliasList,
>> - params->block_bitmap_mapping);
>> - }
>> -
>> - if (params->has_x_vcpu_dirty_limit_period) {
>> - s->parameters.x_vcpu_dirty_limit_period =
>> - params->x_vcpu_dirty_limit_period;
>> - }
>> - if (params->has_vcpu_dirty_limit) {
>> - s->parameters.vcpu_dirty_limit = params->vcpu_dirty_limit;
>> - }
>> -
>> - if (params->has_mode) {
>> - s->parameters.mode = params->mode;
>> - }
>> -
>> - if (params->has_zero_page_detection) {
>> - s->parameters.zero_page_detection = params->zero_page_detection;
>> - }
>> -
>> - if (params->has_direct_io) {
>> - s->parameters.direct_io = params->direct_io;
>> - }
>> + migrate_tls_opts_free(cur);
>> + qapi_free_BitmapMigrationNodeAliasList(cur->block_bitmap_mapping);
>
> So we free these without resetting the pointers. Now, for example,
> cur->tls_creds can point to garbage. Then..
>
>> + QAPI_CLONE_MEMBERS(MigrationParameters, cur, params);
>
> How does this patch guarantee cur->tls_creds's garbage pointer being
> updated? What if params->tls_creds is NULL? Could it?
>
As you've spotted later in the series, all callers of
migrate_params_apply() provide a MigrationParameters struct with all
has_* fields set.
>> }
>>
>> void qmp_migrate_set_parameters(MigrationParameters *params, Error **errp)
>> @@ -1487,7 +1378,7 @@ void qmp_migrate_set_parameters(MigrationParameters
>> *params, Error **errp)
>> }
>>
>> if (migrate_params_check(&tmp, errp)) {
>> - migrate_params_apply(params);
>> + migrate_params_apply(&tmp);
>> migrate_post_update_params(params, errp);
>> }
>>
>> --
>> 2.35.3
>>
