On Mon, 28 May 2018 11:20:36 +0200 Cédric Le Goater <c...@kaod.org> wrote:
> On 05/28/2018 09:18 AM, Thomas Huth wrote: > > On 28.05.2018 09:06, Cédric Le Goater wrote: > >> On 05/28/2018 08:17 AM, Thomas Huth wrote: > >>> On 25.05.2018 16:02, Greg Kurz wrote: > >>>> On Fri, 18 May 2018 18:44:02 +0200 > >>>> Cédric Le Goater <c...@kaod.org> wrote: > >>>> > >>>>> This IRQ number hint can possibly be used by the VIO devices if the > >>>>> "irq" property is defined on the command line but it seems it is never > >>>>> the case. It is not used in libvirt for instance. So, let's remove it > >>>>> to simplify future changes. > >>>>> > >>>> > >>>> Setting an irq manually looks a bit anachronistic. I doubt anyone would > >>>> do that nowadays, and the patch does a nice cleanup. So this looks like > >>>> a good idea. > >>> [...] > >>>>> diff --git a/hw/ppc/spapr_vio.c b/hw/ppc/spapr_vio.c > >>>>> index 472dd6f33a96..cc064f64fccf 100644 > >>>>> --- a/hw/ppc/spapr_vio.c > >>>>> +++ b/hw/ppc/spapr_vio.c > >>>>> @@ -455,7 +455,7 @@ static void spapr_vio_busdev_realize(DeviceState > >>>>> *qdev, Error **errp) > >>>>> dev->qdev.id = id; > >>>>> } > >>>>> > >>>>> - dev->irq = spapr_irq_alloc(spapr, dev->irq, false, &local_err); > >>>>> + dev->irq = spapr_irq_alloc(spapr, false, &local_err); > >>>> > >>>> Silently breaking "irq" like this looks wrong. I'd rather officially > >>>> remove > >>>> it first (ie, kill spapr_vio_props, -5 lines in spapr_vio.c). > >>>> > >>>> Of course, this raises the question of interface deprecation, and it > >>>> should > >>>> theoretically follow the process described at: > >>>> > >>>> https://wiki.qemu.org/Features/LegacyRemoval#Rules_for_removing_an_interface > >>>> > >>>> Cc'ing Thomas, our Chief Deprecation Officer, for insights :) > >>> > >>> The property is a public interface. Just because it's not used by > >>> libvirt does not mean that nobody is using it. So yes, please follow the > >>> rules and mark it as deprecated first for two release, before you really > >>> remove it. > >> > >> This "irq" property is a problem to introduce a new static layout of IRQ > >> numbers. It is in complete opposition. > >> > >> Can we keep it as it is for old pseries machine (settable) and ignore it > >> for newer ? Would that be fine ? > > > > I think that would be fine, too. You likely need to keep the settable > > IRQs around for the old machines anyway, to make sure that migration of > > the old machine types still works, right? > > Yes, that is the goal of patch 3. It introduces a common sPAPR IRQ frontend, > the first backend being the current one. > If we keep "irq" but we ignore it with newer machine types, we should at least print a warning then IMHO. > C. >
