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envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.237, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Tue, Jul 01, 2025 at 08:38:19AM +0200, Markus Armbruster wrote: > Fabiano Rosas writes: > > > The MigrationState is a QOM object with TYPE_DEVICE as a parent. This > > was done about eight years ago so the migration code could make use of > > qdev properties to define the defaults for the migration parameters > > and to be able to expose migration knobs for debugging via the > > '-global migration' command line option. > > > > Due to unrelated historical reasons, three of the migration parameters > > (TLS options) received different types when used via the > > query-migrate-parameters QMP command than with the > > migrate-set-parameters command. This has created a lot of duplication > > in the migration code and in the QAPI documentation because the whole > > of MigrationParameters had to be duplicated as well. > > > > The migration code is now being fixed to remove the duplication and > > for that to happen the offending fields need to be reconciled into a > > single type. The StrOrNull type is going to be used. > > > > To keep the command line compatibility, the parameters need to > > continue being exposed via qdev properties accessible from the command > > line. Introduce a qdev property StrOrNull just for that. > > > > Note that this code is being kept in migration/options.c because this > > version of StrOrNull doesn't need to handle QNULL because it was never > > a valid option in the previous command line, which took a string. > > > > Signed-off-by: Fabiano Rosas > > --- > > migration/options.c | 47 +++++++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 47 insertions(+) > > > > diff --git a/migration/options.c b/migration/options.c > > index 162c72cda4..384ef9e421 100644 > > --- a/migration/options.c > > +++ b/migration/options.c > > @@ -83,6 +83,11 @@ > > #define DEFINE_PROP_MIG_CAP(name, x) \ > > DEFINE_PROP_BOOL(name, MigrationState, capabilities[x], false) > > > > +const PropertyInfo qdev_prop_StrOrNull; > > +#define DEFINE_PROP_STR_OR_NULL(_name, _state, _field) \ > > + DEFINE_PROP(_name, _state, _field, qdev_prop_StrOrNull, StrOrNull *, \ > > + .set_default = true) > > + > > #define DEFAULT_MIGRATE_VCPU_DIRTY_LIMIT_PERIOD 1000 /* milliseconds */ > > #define DEFAULT_MIGRATE_VCPU_DIRTY_LIMIT 1 /* MB/s */ > > > > @@ -204,6 +209,48 @@ const Property migration_properties[] = { > > }; > > const size_t migration_properties_count = ARRAY_SIZE(migration_properties); > > > > +/* > > + * qdev property for TLS options handling via '-global migration' > > + * command line. > > + */ > > Looks like this was a function comment. It's not, it applies to the > PropertyInfo and its method. Move it to the PropertyInfo? > > Maybe > > /* > * String property like qdev_prop_string, except it's backed by a > * StrOrNull * instead of a char *. This is intended for > * TYPE_MIGRATION's TLS options. > */ > > > +static void set_StrOrNull(Object *obj, Visitor *v, const char *name, > > + void *opaque, Error **errp) > > +{ > > + const Property *prop = opaque; > > + StrOrNull **ptr = object_field_prop_ptr(obj, prop); > > + StrOrNull *str_or_null = g_new0(StrOrNull, 1); > > + > > + /* > > + * Only str to keep compatibility, QNULL was never used via > > + * command line. > > + */ > > + str_or_null->type = QTYPE_QSTRING; > > + if (!visit_type_str(v, name, &str_or_null->u.s, errp)) { > > + return; > > + } > > + > > + qapi_free_StrOrNull(*ptr); > > + *ptr = str_or_null; > > +} > > + > > +static void release_StrOrNull(Object *obj, const char *name, void *opaque) > > +{ > > + const Property *prop = opaque; > > + qapi_free_StrOrNull(*(StrOrNull **)object_field_prop_ptr(obj, prop)); > > +} > > + > > +static void set_default_value_tls_opt(ObjectProperty *op, const Property *prop) > > +{ > > + object_property_set_default_str(op, ""); > > +} > > + > > +const PropertyInfo qdev_prop_StrOrNull = { > > + .type = "StrOrNull", > > + .set = set_StrOrNull, > > + .release = release_StrOrNull, > > + .set_default_value = set_default_value_tls_opt, > > +}; > > No getter, i.e. properties will be write-only. This is unusual. Is it > safe? Fair question.. I had a quick look, device_class_set_props_n() will try to register the prop with legacy mode first then modern mode. Legacy mode is decided by [1] below: static void qdev_class_add_legacy_property(DeviceClass *dc, const Property *prop) { g_autofree char *name = NULL; /* Register pointer properties as legacy properties */ if (!prop->info->print && prop->info->get) { <------------------ [1] return; } name = g_strdup_printf("legacy-%s", prop->name); object_class_property_add(OBJECT_CLASS(dc), name, "str", prop->info->print ? qdev_get_legacy_property : prop->info->get, NULL, NULL, (Property *)prop); } When with no get(), it seems it'll be wrongly treated as legacy property.. which further means whoever tries to get() on the property will invoke qdev_get_legacy_property(), and likely crash on accessing info->print().. The other issue is legacy property doesn't look like to provide a setter function.. as it's passing NULL to object_class_property_add(set=XXX). Likely we'll need to provide get() if without changing qdev code. > > > + > > bool migrate_auto_converge(void) > > { > > MigrationState *s = migrate_get_current(); > -- Peter Xu