[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH 03/12] qom: Make object_class_property_add_uint*_ptr() get of
From: |
Eduardo Habkost |
Subject: |
Re: [PATCH 03/12] qom: Make object_class_property_add_uint*_ptr() get offset |
Date: |
Thu, 29 Oct 2020 08:56:34 -0400 |
On Wed, Oct 28, 2020 at 04:22:40PM +0100, Paolo Bonzini wrote:
> On 23/10/20 17:33, Igor Mammedov wrote:
> > On Wed, 21 Oct 2020 09:30:41 -0400
> > Eduardo Habkost <ehabkost@redhat.com> wrote:
> >
> >> On Wed, Oct 21, 2020 at 02:24:08PM +0200, Igor Mammedov wrote:
> >>> On Fri, 9 Oct 2020 12:01:13 -0400
> >>> Eduardo Habkost <ehabkost@redhat.com> wrote:
> >>>
> >>>> The existing object_class_property_add_uint*_ptr() functions are
> >>>> not very useful, because they need a pointer to the property
> >>>> value, which can't really be provided before the object is
> >>>> created.
> >>>>
> >>>> Replace the pointer parameter in those functions with a
> >>>> `ptrdiff_t offset` parameter.
> >>>>
> >>>> Include a uint8 class property in check-qom-proplist unit tests,
> >>>> to ensure the feature is working.
> >>>
> >>>
> >>> Not sure I like approach, it's reinventing qdev pointer properties in QOM
> >>> form.
> >>
> >> Yes, and that's on purpose. If we want to eventually merge the
> >> two competing APIs into a single one, we need to make them
> >> converge.
> >>
> >>> I had an impression that Paolo wanted qdev pointer properties be gone
> >>> and replaced by something like link properties.
> >>
> >> This is completely unrelated to qdev pointer properties and link
> >> properties. The properties that use object_property_add_uint*_ptr()
> >> today are not qdev pointer properties and will never be link
> >> properties. They are just integer properties.
>
> I think this series a step in the right direction, but please take more
> "inspiration" from link properties, which are done right. In
> particular, properties should have an optional check function and be
> read-only unless the check function is there.
>
> You can make the check function take an uint64_t for simplicity, so that
> all the check functions for uint properties have the same prototype.
> For example a single "property_check_uint_allow" function can allow
> setting the property (which is almost always wrong, but an easy cop out
> for this series).
A property check callback that needs the property value is a more
complex use case, and would require too much property-type-specific
boilerplate today. I plan to address it, but not right now.
In my next series that makes static properties usable by any QOM
object, I will add a separate "allow_set" callback to the
internal QOM property API, which will not take the property value
as argument. This would be enough for the dev->realized checks
that are currently in qdev.
Interestingly, there is only one link property check callback
function in the QEMU tree that actually cares about the property
value: isa_ipmi_bmc_check(). All other cases either don't care
about the property value at all (qdev_prop_allow_set_link_before_realize(),
object_property_allow_set_link()), or are being misused for
something other than property checking (xlnx_dp_set_dpdma()).
--
Eduardo
- Re: [PATCH 03/12] qom: Make object_class_property_add_uint*_ptr() get offset, (continued)
- Re: [PATCH 03/12] qom: Make object_class_property_add_uint*_ptr() get offset, Eric Blake, 2020/10/09
- Re: [PATCH 03/12] qom: Make object_class_property_add_uint*_ptr() get offset, Igor Mammedov, 2020/10/21
- Re: [PATCH 03/12] qom: Make object_class_property_add_uint*_ptr() get offset, Igor Mammedov, 2020/10/23
- Re: [PATCH 03/12] qom: Make object_class_property_add_uint*_ptr() get offset, Eduardo Habkost, 2020/10/27
- Re: [PATCH 03/12] qom: Make object_class_property_add_uint*_ptr() get offset, Paolo Bonzini, 2020/10/28
- Re: [PATCH 03/12] qom: Make object_class_property_add_uint*_ptr() get offset, Igor Mammedov, 2020/10/28
- Re: [PATCH 03/12] qom: Make object_class_property_add_uint*_ptr() get offset,
Eduardo Habkost <=
- Re: [PATCH 03/12] qom: Make object_class_property_add_uint*_ptr() get offset, Igor Mammedov, 2020/10/29
[PATCH 06/12] can_host: Use class properties, Eduardo Habkost, 2020/10/09
[PATCH 05/12] rng: Use class properties, Eduardo Habkost, 2020/10/09
[PATCH 07/12] colo: Use class properties, Eduardo Habkost, 2020/10/09
[PATCH 09/12] netfilter: Use class properties, Eduardo Habkost, 2020/10/09
[PATCH 10/12] input: Use class properties, Eduardo Habkost, 2020/10/09
[PATCH 08/12] netfilter: Reorder functions, Eduardo Habkost, 2020/10/09
[PATCH 12/12] [RFC] qom: Lock properties of all TYPE_USER_CREATABLE types, Eduardo Habkost, 2020/10/09