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.


With regards,
Daniel
-- 
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