qom: Drop parameter @errp of object_property_add() & friends

The only way object_property_add() can fail is when a property with
the same name already exists.  Since our property names are all
hardcoded, failure is a programming error, and the appropriate way to
handle it is passing &error_abort.

Same for its variants, except for object_property_add_child(), which
additionally fails when the child already has a parent.  Parentage is
also under program control, so this is a programming error, too.

We have a bit over 500 callers.  Almost half of them pass
&error_abort, slightly fewer ignore errors, one test case handles
errors, and the remaining few callers pass them to their own callers.

The previous few commits demonstrated once again that ignoring
programming errors is a bad idea.

Of the few ones that pass on errors, several violate the Error API.
The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.  ich9_pm_add_properties(), sparc32_ledma_realize(),
sparc32_dma_realize(), xilinx_axidma_realize(), xilinx_enet_realize()
are wrong that way.

When the one appropriate choice of argument is &error_abort, letting
users pick the argument is a bad idea.

Drop parameter @errp and assert the preconditions instead.

There's one exception to "duplicate property name is a programming
error": the way object_property_add() implements the magic (and
undocumented) "automatic arrayification".  Don't drop @errp there.
Instead, rename object_property_add() to object_property_try_add(),
and add the obvious wrapper object_property_add().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-15-armbru@redhat.com>
[Two semantic rebase conflicts resolved]

1 files changed, 10 insertions, 11 deletions

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index de66def..c41d5f9 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -959,10 +959,9 @@ static PFlashCFI01 *virt_flash_create1(VirtMachineState *vms,
     qdev_prop_set_uint16(dev, "id2", 0x00);
     qdev_prop_set_uint16(dev, "id3", 0x00);
     qdev_prop_set_string(dev, "name", name);
-    object_property_add_child(OBJECT(vms), name, OBJECT(dev),
-                              &error_abort);
+    object_property_add_child(OBJECT(vms), name, OBJECT(dev));
     object_property_add_alias(OBJECT(vms), alias_prop_name,
-                              OBJECT(dev), "drive", &error_abort);
+                              OBJECT(dev), "drive");
     return PFLASH_CFI01(dev);
 }
 
@@ -2270,7 +2269,7 @@ static void virt_machine_class_init(ObjectClass *oc, void *data)
 
     object_class_property_add(oc, "acpi", "OnOffAuto",
         virt_get_acpi, virt_set_acpi,
-        NULL, NULL, &error_abort);
+        NULL, NULL);
     object_class_property_set_description(oc, "acpi",
         "Enable ACPI");
 }
@@ -2286,7 +2285,7 @@ static void virt_instance_init(Object *obj)
      */
     vms->secure = false;
     object_property_add_bool(obj, "secure", virt_get_secure,
-                             virt_set_secure, NULL);
+                             virt_set_secure);
     object_property_set_description(obj, "secure",
                                     "Set on/off to enable/disable the ARM "
                                     "Security Extensions (TrustZone)");
@@ -2294,7 +2293,7 @@ static void virt_instance_init(Object *obj)
     /* EL2 is also disabled by default, for similar reasons */
     vms->virt = false;
     object_property_add_bool(obj, "virtualization", virt_get_virt,
-                             virt_set_virt, NULL);
+                             virt_set_virt);
     object_property_set_description(obj, "virtualization",
                                     "Set on/off to enable/disable emulating a "
                                     "guest CPU which implements the ARM "
@@ -2303,13 +2302,13 @@ static void virt_instance_init(Object *obj)
     /* High memory is enabled by default */
     vms->highmem = true;
     object_property_add_bool(obj, "highmem", virt_get_highmem,
-                             virt_set_highmem, NULL);
+                             virt_set_highmem);
     object_property_set_description(obj, "highmem",
                                     "Set on/off to enable/disable using "
                                     "physical address space above 32 bits");
     vms->gic_version = VIRT_GIC_VERSION_NOSEL;
     object_property_add_str(obj, "gic-version", virt_get_gic_version,
-                        virt_set_gic_version, NULL);
+                        virt_set_gic_version);
     object_property_set_description(obj, "gic-version",
                                     "Set GIC version. "
                                     "Valid values are 2, 3, host and max");
@@ -2322,7 +2321,7 @@ static void virt_instance_init(Object *obj)
         /* Default allows ITS instantiation */
         vms->its = true;
         object_property_add_bool(obj, "its", virt_get_its,
-                                 virt_set_its, NULL);
+                                 virt_set_its);
         object_property_set_description(obj, "its",
                                         "Set on/off to enable/disable "
                                         "ITS instantiation");
@@ -2330,7 +2329,7 @@ static void virt_instance_init(Object *obj)
 
     /* Default disallows iommu instantiation */
     vms->iommu = VIRT_IOMMU_NONE;
-    object_property_add_str(obj, "iommu", virt_get_iommu, virt_set_iommu, NULL);
+    object_property_add_str(obj, "iommu", virt_get_iommu, virt_set_iommu);
     object_property_set_description(obj, "iommu",
                                     "Set the IOMMU type. "
                                     "Valid values are none and smmuv3");
@@ -2338,7 +2337,7 @@ static void virt_instance_init(Object *obj)
     /* Default disallows RAS instantiation */
     vms->ras = false;
     object_property_add_bool(obj, "ras", virt_get_ras,
-                             virt_set_ras, NULL);
+                             virt_set_ras);
     object_property_set_description(obj, "ras",
                                     "Set on/off to enable/disable reporting host memory errors "
                                     "to a KVM guest using ACPI and guest external abort exceptions");