Re: [Qemu-devel] [PATCH 07/11] spapr: add hotplug interrupt machine options

[Michael Roth]

Quoting David Gibson (2016-10-13 23:38:19)
> On Wed, Oct 12, 2016 at 06:13:55PM -0500, Michael Roth wrote:
> > This adds machine options of the form:
> > 
> >   -machine pseries,legacy-hotplug-events=true
> >   -machine pseries,legacy-hotplug-events=false
> > 
> > to denote whether or not we wish to force the use of "legacy" style
> > hotplug events, which are surfaced through EPOW interrupts instead of
> > a dedicated interrupt source, and lack certain features necessary,
> > mainly, for memory unplug support.
> > 
> > If false, QEMU will default to "legacy" style unless the guest
> > advertises support for the newer events via
> > ibm,client-architecture-support hcall during early boot.
> > 
> > For pseries-2.7 and earlier we default to true, for newer machine
> > types we default to false.
> > 
> > Signed-off-by: Michael Roth <address@hidden>
> 
> Hrm.. I think it would be a little clearer if you could find a wording
> such that both the internal variable and the external property have
> the same sense - i.e. get rid of the ! in the property getters /
> setters.

Ok, wasn't sure which direction was more useful from user standpoint. I
think something like modern-hotplug-events=true|false might be
reasonable though.

> 
> > ---
> >  hw/ppc/spapr.c              | 31 +++++++++++++++++++++++++++++++
> >  include/hw/ppc/spapr.h      |  1 +
> >  include/hw/ppc/spapr_ovec.h |  1 +
> >  3 files changed, 33 insertions(+)
> > 
> > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > index f8cde92..d80a6fa 100644
> > --- a/hw/ppc/spapr.c
> > +++ b/hw/ppc/spapr.c
> > @@ -1816,6 +1816,11 @@ static void ppc_spapr_init(MachineState *machine)
> >  
> >      spapr_ovec_set(spapr->ov5, OV5_FORM1_AFFINITY);
> >  
> > +    /* use dedicated HP event source if guest supports it */
> > +    if (spapr->use_hotplug_event_source) {
> > +        spapr_ovec_set(spapr->ov5, OV5_HP_EVT);
> > +    }
> > +
> >      /* init CPUs */
> >      if (machine->cpu_model == NULL) {
> >          machine->cpu_model = kvm_enabled() ? "host" : smc->tcg_default_cpu;
> > @@ -2172,16 +2177,39 @@ static void spapr_set_kvm_type(Object *obj, const 
> > char *value, Error **errp)
> >      spapr->kvm_type = g_strdup(value);
> >  }
> >  
> > +static bool spapr_get_legacy_hotplug_events(Object *obj, Error **errp)
> > +{
> > +    sPAPRMachineState *spapr = SPAPR_MACHINE(obj);
> > +
> > +    return !spapr->use_hotplug_event_source;
> > +}
> > +
> > +static void spapr_set_legacy_hotplug_events(Object *obj, bool value,
> > +                                            Error **errp)
> > +{
> > +    sPAPRMachineState *spapr = SPAPR_MACHINE(obj);
> > +
> > +    spapr->use_hotplug_event_source = !value;
> > +}
> > +
> >  static void spapr_machine_initfn(Object *obj)
> >  {
> >      sPAPRMachineState *spapr = SPAPR_MACHINE(obj);
> >  
> >      spapr->htab_fd = -1;
> > +    spapr->use_hotplug_event_source = true;
> >      object_property_add_str(obj, "kvm-type",
> >                              spapr_get_kvm_type, spapr_set_kvm_type, NULL);
> >      object_property_set_description(obj, "kvm-type",
> >                                      "Specifies the KVM virtualization mode 
> > (HV, PR)",
> >                                      NULL);
> > +    object_property_add_bool(obj, "legacy-hotplug-events",
> > +                            spapr_get_legacy_hotplug_events,
> > +                            spapr_set_legacy_hotplug_events,
> > +                            NULL);
> > +    object_property_set_description(obj, "legacy-hotplug-events",
> > +                                    "Use deprecated EPOW mechanism for 
> > hotplug events",
> > +                                    NULL);
> >  }
> >  
> >  static void spapr_machine_finalizefn(Object *obj)
> > @@ -2518,6 +2546,9 @@ DEFINE_SPAPR_MACHINE(2_8, "2.8", true);
> >  
> >  static void spapr_machine_2_7_instance_options(MachineState *machine)
> >  {
> > +    sPAPRMachineState *spapr = SPAPR_MACHINE(machine);
> > +
> > +    spapr->use_hotplug_event_source = false;
> >  }
> >  
> >  static void spapr_machine_2_7_class_options(MachineClass *mc)
> > diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> > index 27a3328..d1a4a14 100644
> > --- a/include/hw/ppc/spapr.h
> > +++ b/include/hw/ppc/spapr.h
> > @@ -74,6 +74,7 @@ struct sPAPRMachineState {
> >      uint32_t check_exception_irq;
> >      Notifier epow_notifier;
> >      QTAILQ_HEAD(, sPAPREventLogEntry) pending_events;
> > +    bool use_hotplug_event_source;
> >  
> >      /* Migration state */
> >      int htab_save_index;
> > diff --git a/include/hw/ppc/spapr_ovec.h b/include/hw/ppc/spapr_ovec.h
> > index 47fa04c..92167c6 100644
> > --- a/include/hw/ppc/spapr_ovec.h
> > +++ b/include/hw/ppc/spapr_ovec.h
> > @@ -45,6 +45,7 @@ typedef struct sPAPROptionVector sPAPROptionVector;
> >  /* option vector 5 */
> >  #define OV5_DRCONF_MEMORY       OV_BIT(2, 2)
> >  #define OV5_FORM1_AFFINITY      OV_BIT(5, 0)
> > +#define OV5_HP_EVT              OV_BIT(6, 5)
> >  
> >  /* interfaces */
> >  sPAPROptionVector *spapr_ovec_new(void);
> 
> -- 
> 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