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

[David Gibson <david@gibson.dropbear.id.au>]

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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 <mdroth@linux.vnet.ibm.com>

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.

> ---
>  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

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