Daniel P. Berrangé <[email protected]> writes:

> On Wed, Jul 08, 2026 at 01:21:49PM +0200, Markus Armbruster wrote:
>> Daniel P. Berrangé <[email protected]> writes:
>> 
>> > On Wed, Jul 08, 2026 at 11:16:30AM +0100, Peter Maydell wrote:
>> >> On Fri, 3 Jul 2026 at 10:09, Mark Cave-Ayland
>> >> <[email protected]> wrote:
>> >> >
>> >> > Signed-off-by: Mark Cave-Ayland <[email protected]>
>> >> > ---
>> >> >  include/hw/i386/pc.h | 2 ++
>> >> >  hw/i386/pc.c         | 8 ++++++++
>> >> >  hw/i386/pc_sysfw.c   | 7 +------
>> >> >  3 files changed, 11 insertions(+), 6 deletions(-)
>> >> >
>> >> > diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
>> >> > index 309de2eda1..16cb0ec01f 100644
>> >> > --- a/include/hw/i386/pc.h
>> >> > +++ b/include/hw/i386/pc.h
>> >> > @@ -40,6 +40,8 @@ typedef struct PCMachineState {
>> >> >
>> >> >      Object *alias_pcspk;
>> >> >      Object *alias_rtc_time;
>> >> > +    Object *alias_pflash0;
>> >> > +    Object *alias_pflash1;
>> >> >
>> >> >      /* Configuration options: */
>> >> >      uint64_t max_ram_below_4g;
>> >> > diff --git a/hw/i386/pc.c b/hw/i386/pc.c
>> >> > index 13c9c1bfc8..11eef176f4 100644
>> >> > --- a/hw/i386/pc.c
>> >> > +++ b/hw/i386/pc.c
>> >> > @@ -1762,6 +1762,14 @@ static void pc_machine_class_init(ObjectClass 
>> >> > *oc, const void *data)
>> >> >                                     offsetof(X86MachineState, acpi_dev),
>> >> >                                     object_property_allow_set_link,
>> >> >                                     OBJ_PROP_LINK_STRONG);
>> >> > +    object_class_property_add_alias(oc, "pflash0",
>> >> > +                                    offsetof(PCMachineState, 
>> >> > alias_pflash0),
>> >> > +                                    TYPE_PFLASH_CFI01,
>> >> > +                                    "drive");
>> >> > +    object_class_property_add_alias(oc, "pflash1",
>> >> > +                                    offsetof(PCMachineState, 
>> >> > alias_pflash1),
>> >> > +                                    TYPE_PFLASH_CFI01,
>> >> > +                                    "drive");
>> >> 
>> >> Does making these class properties fix
>> >> https://gitlab.com/qemu-project/qemu/-/work_items/3254
>> >> (which is a report that "qemu-system-x86_64 -machine pc-q35,help"
>> >> doesn't list these properties) ?
>> 
>> Not showing object properties is a bug.
>> 
>> Cannot be fixed for object properties that are created outside the
>> object's instance_init().
>> 
>> Now, object properties created in instance_init() should almost
>> certainly be class properties instead.  Converting them all fixes the
>> fixable part of the bug:
>> 
>> > Yes, it ought to, as that CLI logic iterates over class properties.
>> 
>> One property conversion at a time.
>> 
>> There's a quicker fix, though.
>> 
>> -machine TYPE.help uses type_print_class_properties() to show
>> properties.  Here's its loop:
>> 
>>     object_class_property_iter_init(&iter, klass);
>>     while ((prop = object_property_iter_next(&iter))) {
>>         if (!prop->set) {
>>             continue;
>>         }
>> 
>>         g_ptr_array_add(array,
>>                         object_property_help(prop->name, prop->type,
>>                                              prop->defval, 
>> prop->description));
>>     }
>> 
>> -device TYPE,help uses qmp_device_list_properties() to show both.
>> Here's its loop:
>> 
>>         obj = object_new_with_class(klass);
>> 
>>         object_property_iter_init(&iter, obj);
>>         while ((prop = object_property_iter_next(&iter))) {
>>             ObjectPropertyInfo *info;
>> 
>>             [...]
>> 
>>             info = g_new0(ObjectPropertyInfo, 1);
>>             info->name = g_strdup(prop->name);
>>             info->type = g_strdup(prop->type);
>>             info->description = g_strdup(prop->description);
>>             info->default_value = qobject_ref(prop->defval);
>> 
>>             QAPI_LIST_PREPEND(prop_list, info);
>>         }
>> 
>>         object_unref(obj);
>> 
>> Is there any excuse not to do it this way?
>
> Something would need to validate that instantiating a machine type
> for help usage won't trip over any edge cases. Could be done with
> unit tests.

tests/qtest/device-introspect-test.c covers this for devices.


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