Re: [Qemu-devel] [PATCH] ACPI: call acpi_set_pci_info when only acpi enabled

[Stefano Stabellini]

On Thu, 27 Apr 2017, Igor Mammedov wrote:
> On Thu, 27 Apr 2017 10:51:23 -0600
> "Bruce Rogers" <address@hidden> wrote:
> 
> > 
> > 
> > >>> On 4/27/2017 at 10:08 AM, Igor Mammedov <address@hidden> wrote: 
> > > On Thu, 27 Apr 2017 09:44:31 -0600
> > > "Bruce Rogers" <address@hidden> wrote:
> > > 
> > >> >>> On 4/27/2017 at 03:11 AM, Igor Mammedov <address@hidden> wrote: 
> > >> > On Wed, 26 Apr 2017 13:07:02 -0600
> > >> > Bruce Rogers <address@hidden> wrote:
> > >> > 
> > >> >> Commit f0c9d64a exposed an issue with the code order in acpi_setup.
> > >> >> As of that commit, a xenfv machine type guest will no longer start
> > >> >> if using pci passthrough. Re-order the code in that function to
> > >> >> allow acpi_set_pci_info to be called before bailing on the other,
> > >> >> non-related conditions. With this change I can again use pci
> > >> >> passthrough and xenfv together.
> > >> >> 
> > >> >> Signed-off-by: Bruce Rogers <address@hidden>
> > >> > it doesn't look right,
> > >> > acpi_set_pci_info() is supposed to affect only ACPI based hotplug
> > >> > 
> > >> > could you elaborate more on what's going on and
> > >> > what error you see at startup?
> > >> 
> > >> I am using libvirt, driving the creation of the Xen HVM guest via
> > >> libxl. libxl dynamically attaches the pci device via QMP. In the
> > >> context of qmp_device_add(), we get a failure in hw/acpi/pcihp.c:
> > >> acpi_pcihp_device_plug_cb() when it checks for bsel, and errors
> > >> with the message: "Unsupported bus. Bus doesn't have property
> > >> 'acpi-pcihp-bsel' set". I guess it wasn't clear from my description
> > >> that hotplug was involved.
> > >> 
> > > is dev->hotplugged in acpi_pcihp_device_plug_cb() true at that time?
> > > 
> > > the point is that bsel is needed only when there is supporting ACPI code
> > > and useless otherwise, so acpi_pcihp_device_plug_cb() probably shouldn't
> > > run under xenfv. I'd try to add compat prop to PIIX4_PM and disable
> > > acpi_pcihp_device_plug_cb() for xenfv via machine compat property.
> > 
> > So what would be wrong with simply conditionalizing the call to 
> >  acpi_pcihp_device_plug_cb() with a check for xen in piix4_device_plug_cb()
> > as follows:
> > 
> >          }
> >      } else if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
> > -        acpi_pcihp_device_plug_cb(hotplug_dev, &s->acpi_pci_hotplug, dev, 
> > errp);
> > +        if (!xen_enabled()) {
> > +            acpi_pcihp_device_plug_cb(hotplug_dev, &s->acpi_pci_hotplug, 
> > dev,
> > +                                      errp);
> > +        }
> >      } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
> >          if (s->cpu_hotplug_legacy) {
> >              legacy_acpi_cpu_plug_cb(hotplug_dev, &s->gpe_cpu, dev, errp);
> > 
> > Wouldn't that be the solution?
> it should work
> 
> is it possible to see unplug on that device later under xen?

Yes, it would be possible. I guess we need to do the same for
acpi_pcihp_device_unplug_cb?