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

[Igor Mammedov]

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?

> 
> Bruce
> 
>