Re: [Qemu-devel] [PATCH] ppc/xics: fix XICSStateClass parent class

[Cédric Le Goater]

On 02/14/2017 02:58 AM, David Gibson wrote:
> On Mon, Feb 13, 2017 at 10:33:24AM +0100, Cédric Le Goater wrote:
>> XICSState inherits from SysBusDevice and so the object class should
>> inherit from SysBusDeviceClass.
>>
>> Signed-off-by: Cédric Le Goater <address@hidden>
> 
> That's definitely a bug, but I don't think this is the right fix.
> 
> XICS was put on sysbus back when I thought that was where you put any
> "system" devices that didn't belong on a more specific bus.  I've
> since discovered that's not the case, and - particularly since xics
> doesn't expose any mmio - it shouldn't be a sysbus device at all.
> 
> I've instead made a patch changing it to a direct child of
> TYPE_DEVICE.  Since the device shouldn't ever be command line
> instantiated, and it has no migratable state I believe this should be
> a safe change.
> 
> This is in ppc-for-2.9, tentatively; please review:
> 
> From eae21fcf2430588f17e6a58d505aa8eaa580b507 Mon Sep 17 00:00:00 2001
> From: David Gibson <address@hidden>
> Date: Tue, 14 Feb 2017 12:58:05 +1100
> Subject: [PATCH] xics: XICS should not be a SysBusDevice
> 
> Currently xics - the component of the IBM POWER interrupt controller
> representing the overall interrupt fabric / architecture is represented as
> a descedent of SysBusDevice.  However, this is not really correct - the

descendant ?

> xics presents nothing in MMIO space so it should be an "unattached" device
> in the current QOM model.
> 
> Since this device will always be created by the machine type, not created
> specifically from the command line, and because it has no migrated state
> it should be safe to move it around the device composition tree.
> 
> Therefore this patch changes it to a descendent of TYPE_DEVICE, and makes
> it an unattached device.
> 
> Signed-off-by: David Gibson <address@hidden>

Reviewed-by: Cédric Le Goater <address@hidden>

Thanks,

C.

> ---
>  hw/intc/xics.c | 2 +-
>  hw/ppc/spapr.c | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/intc/xics.c b/hw/intc/xics.c
> index 095c16a..372b831 100644
> --- a/hw/intc/xics.c
> +++ b/hw/intc/xics.c
> @@ -260,7 +260,7 @@ static void xics_common_class_init(ObjectClass *oc, void 
> *data)
>  
>  static const TypeInfo xics_common_info = {
>      .name          = TYPE_XICS_COMMON,
> -    .parent        = TYPE_SYS_BUS_DEVICE,
> +    .parent        = TYPE_DEVICE,
>      .instance_size = sizeof(XICSState),
>      .class_size    = sizeof(XICSStateClass),
>      .instance_init = xics_common_initfn,
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 6f37288..9b6ad0f 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -101,7 +101,7 @@ static XICSState *try_create_xics(const char *type, int 
> nr_servers,
>      Error *err = NULL;
>      DeviceState *dev;
>  
> -    dev = qdev_create(NULL, type);
> +    dev = DEVICE(object_new(type));
>      qdev_prop_set_uint32(dev, "nr_servers", nr_servers);
>      qdev_prop_set_uint32(dev, "nr_irqs", nr_irqs);
>      object_property_set_bool(OBJECT(dev), true, "realized", &err);
>