Re: [Qemu-devel] [PATCH V3 7/7] acpi/cpu-hotplug: introduce help function to keep bit setting in one place

[Igor Mammedov]

On Mon, 29 Sep 2014 17:44:27 +0800
Gu Zheng <address@hidden> wrote:

> On 09/29/2014 05:47 PM, Igor Mammedov wrote:
> 
> > On Mon, 29 Sep 2014 17:22:08 +0800
> > Gu Zheng <address@hidden> wrote:
> > 
> >> Hi Igor,
> >> On 09/26/2014 09:37 PM, Igor Mammedov wrote:
> >>
> >>> On Wed, 17 Sep 2014 09:24:03 +0800
> >>> Gu Zheng <address@hidden> wrote:
> >>>
> >>>> Introduce help function acpi_set_local_sts() to simplify
> >>>> acpi_cpu_plug_cb and acpi_cpu_hotplug_init, so that we can keep
> >>>> bit setting in one place.
> >>>>
> >>>> Signed-off-by: Gu Zheng <address@hidden>
> >>>> ---
> >>>>  hw/acpi/cpu_hotplug.c |   22 +++++++++++++++-------
> >>>>  1 files changed, 15 insertions(+), 7 deletions(-)
> >>>>
> >>>> diff --git a/hw/acpi/cpu_hotplug.c b/hw/acpi/cpu_hotplug.c
> >>>> index 7629686..d42c961 100644
> >>>> --- a/hw/acpi/cpu_hotplug.c
> >>>> +++ b/hw/acpi/cpu_hotplug.c
> >>>> @@ -36,8 +36,8 @@ static const MemoryRegionOps AcpiCpuHotplug_ops
> >>>> = { },
> >>>>  };
> >>>>  
> >>>> -void acpi_cpu_plug_cb(ACPIREGS *ar, qemu_irq irq,
> >>>> -                      AcpiCpuHotplug *g, CPUState *cpu, Error
> >>>> **errp) +static void acpi_set_local_sts(AcpiCpuHotplug *g,
> >>>> CPUState *cpu,
> >>>> +                               Error **errp)
> >>>>  {
> >>>>      CPUClass *k = CPU_GET_CLASS(cpu);
> >>>>      int64_t cpu_id;
> >>>> @@ -48,9 +48,18 @@ void acpi_cpu_plug_cb(ACPIREGS *ar, qemu_irq
> >>>> irq, return;
> >>>>      }
> >>>>  
> >>>> -    ar->gpe.sts[0] |= ACPI_CPU_HOTPLUG_STATUS;
> >>>>      g->sts[cpu_id / 8] |= (1 << (cpu_id % 8));
> >>>> +}
> >>>>  
> >>>> +void acpi_cpu_plug_cb(ACPIREGS *ar, qemu_irq irq,
> >>>> +                      AcpiCpuHotplug *g, CPUState *cpu, Error
> >>>> **errp) +{
> >>>> +    acpi_set_local_sts(g, cpu, errp);
> >>>> +    if (*errp != NULL) {
> >>>> +        return;
> >>>> +    }
> >>>> +
> >>>
> >>>> +    ar->gpe.sts[0] |= ACPI_CPU_HOTPLUG_STATUS;
> >>> ^^^ shouldn't be set for coldplugged CPUs along with IRQ below
> >>>
> >>>>      acpi_update_sci(ar, irq);
> >>>>  }
> >>>>  
> >>>> @@ -60,11 +69,10 @@ void acpi_cpu_hotplug_init(MemoryRegion
> >>>> *parent, Object *owner, CPUState *cpu;
> >>>>  
> >>>>      CPU_FOREACH(cpu) {
> >>>> -        CPUClass *cc = CPU_GET_CLASS(cpu);
> >>>> -        int64_t id = cc->get_arch_id(cpu);
> >>>> +        Error *local_err = NULL;
> >>>>  
> >>>> -        g_assert((id / 8) < ACPI_GPE_PROC_LEN);
> >>>> -        gpe_cpu->sts[id / 8] |= (1 << (id % 8));
> >>>> +        acpi_set_local_sts(gpe_cpu, cpu, &local_err);
> >>>> +        g_assert(local_err == NULL);
> >>> Wouldn't acpi_cpu_plug_cb() do everything this FOREACH does?
> >>> I've suggest to drop CPU_FOREACH() altogether.
> >>
> >> I got your meaning: Make acpi_cpu_plug_cb serve all CPUs (both
> >> startup and hotpluged) , and only triggers sci irq for hotpluged
> >> ones, so that we can drop the duplicated operations in
> >> acpi_cpu_hotplug_init. But one problem is that pcms->acpi_dev was
> >> registered after startup CPUs set realized, so acpi_cpu_plug_cb can
> >> not serve startup CPUs. I tried to switch the order, but it failed,
> >> because there are some internal dependences. Now, I'm trying to
> >> split the startup CPUs init into two steps (init and realize), and
> >> register pcms->acpi_dev between the two steps. What's your opinion?
> > Could you point out what dependecies are there?
> 
> E.g.
> Allocation smi_irq for PIIX4PMState dependents on the valid
> *first_cpu*.
> 
> smi_irq = qemu_allocate_irqs(pc_acpi_smi_interrupt, first_cpu, 1);
> /* TODO: Populate SPD eeprom data.  */
> smbus = piix4_pm_init(pci_bus, piix3_devfn + 3, 0xb100,
>                       gsi[9], *smi_irq,
>                       kvm_enabled(), fw_cfg, &piix4_pm);
Looks like it would be too much trouble for not much gain.
Lets keep this patch as is.

> Thanks,
> Gu
> 
> > 
> >>
> >> Thanks,
> >> Gu
> >>
> >>>
> >>>>      }
> >>>>      memory_region_init_io(&gpe_cpu->io, owner,
> >>>> &AcpiCpuHotplug_ops, gpe_cpu, "acpi-cpu-hotplug",
> >>>> ACPI_GPE_PROC_LEN);
> >>>
> >>> .
> >>>
> >>
> >>
> > 
> > .
> > 
> 
> 
>