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

> On Wed, Jul 08, 2026 at 02:50:54PM +0200, Markus Armbruster wrote:
>> 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.
>
> Ah, good, I was misled by its name into thinking it was only devices,
> not machine types too.

Misunderstanding: it does cover it for devices, and only for devices.


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