MigrationParameters needs to have all of its has_* fields marked as
true when used as the return of query_migrate_parameters because the
corresponding QMP command has all of its members non-optional by
design, despite them being marked as optional in migration.json.

Extract this code into a function and make it assert if any field is
missing. With this we ensure future changes will not inadvertently
leave any parameters missing.

Also assert that s->parameters _does not_ have any of its has_* fields
set. This structure is internal to the migration code and it should
not rely on the QAPI-generate has_* fields. We might want to store
migration parameters differently in the future.

Signed-off-by: Fabiano Rosas <faro...@suse.de>
---
 migration/options.c | 74 ++++++++++++++++++++++++++++-----------------
 1 file changed, 46 insertions(+), 28 deletions(-)

diff --git a/migration/options.c b/migration/options.c
index e2e3ab717f..dd62e726cb 100644
--- a/migration/options.c
+++ b/migration/options.c
@@ -936,6 +936,40 @@ static void tls_option_set_str(StrOrNull **dstp, StrOrNull 
*src)
     }
 }
 
+static void migrate_mark_all_params_present(MigrationParameters *p)
+{
+    int len, n_str_args = 3; /* tls-creds, tls-hostname, tls-authz */
+    bool *has_fields[] = {
+        &p->has_throttle_trigger_threshold, &p->has_cpu_throttle_initial,
+        &p->has_cpu_throttle_increment, &p->has_cpu_throttle_tailslow,
+        &p->has_max_bandwidth, &p->has_avail_switchover_bandwidth,
+        &p->has_downtime_limit, &p->has_x_checkpoint_delay,
+        &p->has_multifd_channels, &p->has_multifd_compression,
+        &p->has_multifd_zlib_level, &p->has_multifd_qatzip_level,
+        &p->has_multifd_zstd_level, &p->has_xbzrle_cache_size,
+        &p->has_max_postcopy_bandwidth, &p->has_max_cpu_throttle,
+        &p->has_announce_initial, &p->has_announce_max, 
&p->has_announce_rounds,
+        &p->has_announce_step, &p->has_block_bitmap_mapping,
+        &p->has_x_vcpu_dirty_limit_period, &p->has_vcpu_dirty_limit,
+        &p->has_mode, &p->has_zero_page_detection, &p->has_direct_io,
+    };
+
+    /*
+     * The has_* fields of MigrationParameters are used by QAPI to
+     * inform whether an optional struct member is present. Keep this
+     * decoupled from the internal usage (not QAPI) by leaving the
+     * has_* fields of s->parameters unused.
+     */
+    assert(p != &(migrate_get_current())->parameters);
+
+    len = ARRAY_SIZE(has_fields);
+    assert(len + n_str_args == MIGRATION_PARAMETER__MAX);
+
+    for (int i = 0; i < len; i++) {
+        *has_fields[i] = true;
+    }
+}
+
 MigrationParameters *qmp_query_migrate_parameters(Error **errp)
 {
     MigrationParameters *params;
@@ -943,68 +977,52 @@ MigrationParameters *qmp_query_migrate_parameters(Error 
**errp)
 
     /* TODO use QAPI_CLONE() instead of duplicating it inline */
     params = g_malloc0(sizeof(*params));
-    params->has_throttle_trigger_threshold = true;
+
     params->throttle_trigger_threshold = 
s->parameters.throttle_trigger_threshold;
-    params->has_cpu_throttle_initial = true;
     params->cpu_throttle_initial = s->parameters.cpu_throttle_initial;
-    params->has_cpu_throttle_increment = true;
     params->cpu_throttle_increment = s->parameters.cpu_throttle_increment;
-    params->has_cpu_throttle_tailslow = true;
     params->cpu_throttle_tailslow = s->parameters.cpu_throttle_tailslow;
 
     tls_option_set_str(&params->tls_creds, s->parameters.tls_creds);
     tls_option_set_str(&params->tls_hostname, s->parameters.tls_hostname);
     tls_option_set_str(&params->tls_authz, s->parameters.tls_authz);
 
-    params->has_max_bandwidth = true;
     params->max_bandwidth = s->parameters.max_bandwidth;
-    params->has_avail_switchover_bandwidth = true;
     params->avail_switchover_bandwidth = 
s->parameters.avail_switchover_bandwidth;
-    params->has_downtime_limit = true;
     params->downtime_limit = s->parameters.downtime_limit;
-    params->has_x_checkpoint_delay = true;
     params->x_checkpoint_delay = s->parameters.x_checkpoint_delay;
-    params->has_multifd_channels = true;
     params->multifd_channels = s->parameters.multifd_channels;
-    params->has_multifd_compression = true;
     params->multifd_compression = s->parameters.multifd_compression;
-    params->has_multifd_zlib_level = true;
     params->multifd_zlib_level = s->parameters.multifd_zlib_level;
-    params->has_multifd_qatzip_level = true;
     params->multifd_qatzip_level = s->parameters.multifd_qatzip_level;
-    params->has_multifd_zstd_level = true;
     params->multifd_zstd_level = s->parameters.multifd_zstd_level;
-    params->has_xbzrle_cache_size = true;
     params->xbzrle_cache_size = s->parameters.xbzrle_cache_size;
-    params->has_max_postcopy_bandwidth = true;
     params->max_postcopy_bandwidth = s->parameters.max_postcopy_bandwidth;
-    params->has_max_cpu_throttle = true;
     params->max_cpu_throttle = s->parameters.max_cpu_throttle;
-    params->has_announce_initial = true;
     params->announce_initial = s->parameters.announce_initial;
-    params->has_announce_max = true;
     params->announce_max = s->parameters.announce_max;
-    params->has_announce_rounds = true;
     params->announce_rounds = s->parameters.announce_rounds;
-    params->has_announce_step = true;
     params->announce_step = s->parameters.announce_step;
-
-    params->has_block_bitmap_mapping = true;
     params->block_bitmap_mapping =
         QAPI_CLONE(BitmapMigrationNodeAliasList,
                    s->parameters.block_bitmap_mapping);
-
-    params->has_x_vcpu_dirty_limit_period = true;
     params->x_vcpu_dirty_limit_period = 
s->parameters.x_vcpu_dirty_limit_period;
-    params->has_vcpu_dirty_limit = true;
     params->vcpu_dirty_limit = s->parameters.vcpu_dirty_limit;
-    params->has_mode = true;
     params->mode = s->parameters.mode;
-    params->has_zero_page_detection = true;
     params->zero_page_detection = s->parameters.zero_page_detection;
-    params->has_direct_io = true;
     params->direct_io = s->parameters.direct_io;
 
+    /*
+     * query-migrate-parameters expects all members of
+     * MigrationParameters to be present, but we cannot mark them
+     * non-optional in QAPI because the structure is also used for
+     * migrate-set-parameters, which needs the optionality. Force all
+     * parameters to be seen as present now. Note that this depends on
+     * some form of default being set for every member of
+     * MigrationParameters, currently done during qdev init using
+     * migration_properties defined in this file.
+     */
+    migrate_mark_all_params_present(params);
     return params;
 }
 
-- 
2.35.3


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