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Tue, 7 Jul 2026 12:17:14 +0000 (UTC) Received: from redhat.com (unknown [10.44.33.142]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A25CC1955F7B; Tue, 7 Jul 2026 12:17:10 +0000 (UTC) Date: Tue, 7 Jul 2026 13:17:07 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Mark Cave-Ayland Cc: mst@redhat.com, imammedo@redhat.com, anisinha@redhat.com, philmd@mailo.com, aurelien@aurel32.net, peter.maydell@linaro.org, pbonzini@redhat.com, richard.henderson@linaro.org, qemu-devel@nongnu.org, qemu-arm@nongnu.org Subject: Re: [PATCH v2 02/12] qom/object.c: add object_class_property_add_uint8_ptr() Message-ID: References: <20260703135512.3213964-1-mark.caveayland@nutanix.com> <20260703135512.3213964-3-mark.caveayland@nutanix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260703135512.3213964-3-mark.caveayland@nutanix.com> User-Agent: Mutt/2.3.2 (2026-04-26) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 8 X-Spam_score: 0.8 X-Spam_bar: / X-Spam_report: (0.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.445, 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_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Fri, Jul 03, 2026 at 02:53:04PM +0100, Mark Cave-Ayland wrote: > This adds a class property that references a uint8_t within the object instance > and is intended to be a replacement for object_property_add_uint8_ptr(). > > Signed-off-by: Mark Cave-Ayland > --- > include/qom/object.h | 5 +++++ > qom/object.c | 52 ++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 57 insertions(+) > > diff --git a/include/qom/object.h b/include/qom/object.h > index 89c23d45ab..a55f9d0e97 100644 > --- a/include/qom/object.h > +++ b/include/qom/object.h > @@ -1956,6 +1956,11 @@ ObjectProperty *object_property_add_uint8_ptr(Object *obj, const char *name, > const uint8_t *v, > ObjectPropertyFlags flags); > > +ObjectProperty *object_class_property_add_uint8_ptr(ObjectClass *klass, > + const char *name, > + ptrdiff_t v, > + ObjectPropertyFlags flags); > + > ObjectProperty *object_class_static_property_add_uint8_ptr(ObjectClass *klass, > const char *name, > const uint8_t *v, > diff --git a/qom/object.c b/qom/object.c > index d10bf848c0..263c313cd2 100644 > --- a/qom/object.c > +++ b/qom/object.c > @@ -2741,6 +2741,38 @@ static void property_set_uint64_ptr(Object *obj, Visitor *v, const char *name, > *field = value; > } > > +static void *object_class_prop_ptr(Object *obj, ptrdiff_t offset) > +{ > + void *ptr = obj; > + ptr += offset; > + > + return ptr; > +} Perhaps just #define FIELD(obj, offset) ((void *)obj+(ptrdiff_t)offset) > + > +static void property_class_get_uint8_ptr(Object *obj, Visitor *v, > + const char *name, > + void *opaque, Error **errp) > +{ > + uint8_t value = *(uint8_t *)object_class_prop_ptr(obj, > + (ptrdiff_t)opaque); Do we need this intermediate instead of now > + visit_type_uint8(v, name, &value, errp); visit_type_uint8(v, name, FIELD(obj, opaque), errp); > +} > + > +static void property_class_set_uint8_ptr(Object *obj, Visitor *v, > + const char *name, > + void *opaque, Error **errp) > +{ > + uint8_t *field = (uint8_t *)object_class_prop_ptr(obj, > + (ptrdiff_t)opaque); > + uint8_t value; > + > + if (!visit_type_uint8(v, name, &value, errp)) { > + return; > + } > + > + *field = value; Instead of all this is it sufficient to do: visit_type_uint8(v, name, FIELD(obj, opaque), errp); Also, since we'll be using this pattern for int8, int16, int32, and many more, perhaps we could define a macro that can expand to the getter/setter impl for any scalar type. so we can do DEFINE_SCALAR_PROP_CALLBACKS(uint8); DEFINE_SCALAR_PROP_CALLBACKS(uint16); DEFINE_SCALAR_PROP_CALLBACKS(uint32); DEFINE_SCALAR_PROP_CALLBACKS(uint64); DEFINE_SCALAR_PROP_CALLBACKS(bool); ..etc.. > +} > + > ObjectProperty * > object_property_add_uint8_ptr(Object *obj, const char *name, > const uint8_t *v, With regards, Daniel -- |: https://berrange.com ~~ https://hachyderm.io/@berrange :| |: https://libvirt.org ~~ https://entangle-photo.org :| |: https://pixelfed.art/berrange ~~ https://fstop138.berrange.com :|