On Thu, Jan 28, 2021 at 01:04:28PM +0100, Greg Kurz wrote: > On Thu, 28 Jan 2021 08:46:01 +0100 > Cédric Le Goater <c...@kaod.org> wrote: > > > On 1/28/21 1:46 AM, Joel Stanley wrote: > > > On Tue, 26 Jan 2021 at 17:14, Cédric Le Goater <c...@kaod.org> wrote: > > >> > > >> and reuse pnv_bmc_set_pnor() to share the setting of the PNOR. > > >> > > >> Signed-off-by: Cédric Le Goater <c...@kaod.org> > > >> --- > > >> hw/ppc/pnv_bmc.c | 7 +------ > > >> 1 file changed, 1 insertion(+), 6 deletions(-) > > >> > > >> diff --git a/hw/ppc/pnv_bmc.c b/hw/ppc/pnv_bmc.c > > >> index 67ebb16c4d5f..86d16b493539 100644 > > >> --- a/hw/ppc/pnv_bmc.c > > >> +++ b/hw/ppc/pnv_bmc.c > > >> @@ -260,13 +260,8 @@ IPMIBmc *pnv_bmc_create(PnvPnor *pnor) > > >> Object *obj; > > >> > > >> obj = object_new(TYPE_IPMI_BMC_SIMULATOR); > > >> - object_ref(OBJECT(pnor)); > > >> - object_property_add_const_link(obj, "pnor", OBJECT(pnor)); > > > > > > I assume it's ok to move the link set to after the realise of the BMC > > > object? > > > > > > When 2 objects need to be linked, one has to be realized first. > > Realize isn't a QOM concept in the first place... > > > I suppose this is why it is allowed but I am not expert in that area. > > > > ... so no surprise object_property_add_const_link() doesn't care > about it. > > > Greg ? > > > > What is important though is that a property with a given name > can only be added *once* to an object during its lifetime. > Doing the contrary is a bug and QEMU aborts. So, with this > in mind, it seems to me that adding QOM properties to a > device object should only be done from some init path > that is only called once. > > > That was the case already when defining a "ipmi-bmc-sim" device on the > > command line. > > > > Yeah and the property is added during machine reset... which > is typically a path that can be taken several times during > the machine lifetime. The potential crash is avoided because > pnv_reset() doesn't call pnv_bmc_set_pnor() if pnv->bmc is > already set, but this is a fragile workaround...
Oof, yeah. In general we should avoid creating or realizing objects
at machine reset time. There might be a few exceptions, but they're
rare.
> A QOM link doesn't look like the correct way to model the BMC
> accesses to the PNOR. Since the only user is hiomap_cmd(),
> it seems you could reach the same result with a pointer to
> the PNOR object being passed to ipmi_sim_register_netfn()
> and later passed to hiomap_cmd().
>
> > C.
> >
> >
> > >> qdev_realize(DEVICE(obj), NULL, &error_fatal);
> > >> -
> > >> - /* Install the HIOMAP protocol handlers to access the PNOR */
> > >> - ipmi_sim_register_netfn(IPMI_BMC_SIMULATOR(obj), IPMI_NETFN_OEM,
> > >> - &hiomap_netfn);
> > >> + pnv_bmc_set_pnor(IPMI_BMC(obj), pnor);
> > >>
> > >> return IPMI_BMC(obj);
> > >> }
> > >>
> > >>
> >
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
signature.asc
Description: PGP signature
