Re: [Qemu-devel] of apci_1_compatible in CPUHotplugFeatures

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Igor Mammedov (imammedo@redhat.com) wrote:
> On Wed, 23 Jan 2019 18:28:59 +0000
> "Dr. David Alan Gilbert" <dgilbert@redhat.com> wrote:
> 
> > * Michael S. Tsirkin (mst@redhat.com) wrote:
> > > On Tue, Jan 22, 2019 at 08:07:41PM +0000, Dr. David Alan Gilbert wrote:  
> > > > Hi,
> > > >   I noticed that the acpi_1_compatible flag was misspelt as
> > > >                      apci_1_compatible
> > > > 
> > > > so have a trivial patch to fix that,
> pls post it.

Done.

> > > > but looking at it - are
> > > > thre any cases where a[cp]i_1_compatible can possibly be false?
> ATM it's not possible, but I've wrote it with intent to reuse
> build_cpus_aml() in arm/virt board and there we shall use newer
> aml_device() instead of legacy aml_processor(), hence a feature flag
> to toggle behavior.

OK, that's fine, I just couldn't see why the flag was there given the
current uses.

Dave

> 
> > > > 
> > > > Dave  
> > > 
> > > legacy_cpu_hotplug so machine 2.6 and older - no?  
> > 
> > That doesn't seem to affect that flag by my reading;
> > the only place I see legacy_cpu_hotplug checked is
> > acpi-build.c:build_dsdt and we have:
> > 
> >     if (pcmc->legacy_cpu_hotplug) {
> >         build_legacy_cpu_hotplug_aml(dsdt, machine, pm->cpu_hp_io_base);
> >     } else {
> >         CPUHotplugFeatures opts = {
> >             .acpi_1_compatible = true, .has_legacy_cphp = true
> >         };
> >         build_cpus_aml(dsdt, machine, opts, pm->cpu_hp_io_base,
> >                        "\\_SB.PCI0", "\\_GPE._E02");
> >     }
> > 
> > so the 'opts' field is only used in the non-legacy case.
> > 
> > That's the only caller of build_cpus_aml, and I'm not seeing another
> > user of CPUHotplugFeatures.
> > 
> > Dave
> > 
> > > > --
> > > > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK  
> > --
> > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK