On Tue, 18 Aug 2020 00:33:19 -0300
Thiago Jung Bauermann <bauer...@linux.ibm.com> wrote:
[...]
> Also change creation of CPU object from cpu_create() to object_new() and
> qdev_realize() because cpu_create() realizes the CPU and it's not possible
> to set a property after the object is realized.
cpu_create was introduced to remove code duplication in simple cases where
we do not need to set properties on created cpu.
returning back to manual object_new + realize() is fine if it 's only
small set of of boards. If it's tree-wide change then that would bring
back all code duplication that cpu_create() got rid of.
An alternative way is to use 'hotplug' callbacks to let board set
additional properties before cpu's realize is called.
example:
hw/ppc/spapr.c:
spapr_machine_class_init()
mc->get_hotplug_handler = spapr_get_hotplug_handler;
hc->pre_plug = spapr_machine_device_pre_plug;
...
static const TypeInfo spapr_machine_info = {
...
{ TYPE_HOTPLUG_HANDLER },
that might work in generic case if it is put into generic machine code,
and existing users of mc->get_hotplug_handler/hc->pre_plug were taken care of.
In which case board would only need to set MachineClass:cpu-start-powered-of
to gate property setting.
> Signed-off-by: Thiago Jung Bauermann <bauer...@linux.ibm.com>
> ---
> hw/ppc/e500.c | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/hw/ppc/e500.c b/hw/ppc/e500.c
> index ab9884e315..0077aca74d 100644
> --- a/hw/ppc/e500.c
> +++ b/hw/ppc/e500.c
> @@ -704,9 +704,6 @@ static void ppce500_cpu_reset_sec(void *opaque)
>
> cpu_reset(cs);
>
> - /* Secondary CPU starts in halted state for now. Needs to change when
> - implementing non-kernel boot. */
> - cs->halted = 1;
> cs->exception_index = EXCP_HLT;
> }
>
> @@ -864,8 +861,9 @@ void ppce500_init(MachineState *machine)
> PowerPCCPU *cpu;
> CPUState *cs;
> qemu_irq *input;
> + Error *err = NULL;
>
> - cpu = POWERPC_CPU(cpu_create(machine->cpu_type));
> + cpu = POWERPC_CPU(object_new(machine->cpu_type));
> env = &cpu->env;
> cs = CPU(cpu);
>
> @@ -897,6 +895,19 @@ void ppce500_init(MachineState *machine)
> } else {
> /* Secondary CPUs */
> qemu_register_reset(ppce500_cpu_reset_sec, cpu);
> +
> + /*
> + * Secondary CPU starts in halted state for now. Needs to change
> + * when implementing non-kernel boot.
> + */
> + object_property_set_bool(OBJECT(cs), "start-powered-off", true,
> + &error_abort);
> + }
> +
> + if (!qdev_realize(DEVICE(cs), NULL, &err)) {
> + error_report_err(err);
> + object_unref(OBJECT(cs));
> + exit(EXIT_FAILURE);
> }
btw:
board leaks cpu reference (from cpu_create()/object_new()) since qdev_realize()
adds it's own and the caller of object_new() is suposed to free the original
one.
in this case qdev_realize_and_unref() fits nicely.
> }
>
>
