Re: [Qemu-devel] [PATCH V3 5/7] pc: Update rtc_cmos in pc_cpu_plug

[Igor Mammedov <imammedo@redhat.com>]

On Wed, 17 Sep 2014 09:24:01 +0800
Gu Zheng <guz.fnst@cn.fujitsu.com> wrote:

> Update rtc_cmos in pc_cpu_plug directly instead of the notifier, with
> this change, there will no user of CPU hot-plug notifier any more, so
> remove it.
> 
> Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
> ---
>  hw/i386/pc.c            |   25 ++++++-------------------
>  include/sysemu/sysemu.h |    3 ---
>  qom/cpu.c               |   10 ----------
>  3 files changed, 6 insertions(+), 32 deletions(-)
> 
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index e25e71b..8b887c7 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -353,20 +353,7 @@ static void pc_cmos_init_late(void *opaque)
>      qemu_unregister_reset(pc_cmos_init_late, opaque);
>  }
>  
> -typedef struct RTCCPUHotplugArg {
> -    Notifier cpu_added_notifier;
> -    ISADevice *rtc_state;
> -} RTCCPUHotplugArg;
> -
> -static void rtc_notify_cpu_added(Notifier *notifier, void *data)
> -{
> -    RTCCPUHotplugArg *arg = container_of(notifier, RTCCPUHotplugArg,
> -                                         cpu_added_notifier);
> -    ISADevice *s = arg->rtc_state;
> -
> -    /* increment the number of CPUs */
> -    rtc_set_memory(s, 0x5f, rtc_get_memory(s, 0x5f) + 1);
> -}
> +static ISADevice *rtc_state;
It's not recommended to use global variables.

Instead of make link<rtc> property in PCMachine and use it pretty much like acpi_dev
is used in 4/7.

>  
>  void pc_cmos_init(ram_addr_t ram_size, ram_addr_t above_4g_mem_size,
>                    const char *boot_device,
> @@ -376,7 +363,6 @@ void pc_cmos_init(ram_addr_t ram_size, ram_addr_t above_4g_mem_size,
>      int val, nb, i;
>      FDriveType fd_type[2] = { FDRIVE_DRV_NONE, FDRIVE_DRV_NONE };
>      static pc_cmos_init_late_arg arg;
> -    static RTCCPUHotplugArg cpu_hotplug_cb;
>  
>      /* various important CMOS locations needed by PC/Bochs bios */
>  
> @@ -415,10 +401,8 @@ void pc_cmos_init(ram_addr_t ram_size, ram_addr_t above_4g_mem_size,
>  
>      /* set the number of CPU */
>      rtc_set_memory(s, 0x5f, smp_cpus - 1);
> -    /* init CPU hotplug notifier */
> -    cpu_hotplug_cb.rtc_state = s;
> -    cpu_hotplug_cb.cpu_added_notifier.notify = rtc_notify_cpu_added;
> -    qemu_register_cpu_added_notifier(&cpu_hotplug_cb.cpu_added_notifier);
> +
> +    rtc_state = s;
>  
>      if (set_boot_dev(s, boot_device)) {
>          exit(1);
> @@ -1630,6 +1614,9 @@ static void pc_cpu_plug(HotplugHandler *hotplug_dev,
>  
>      hhc = HOTPLUG_HANDLER_GET_CLASS(pcms->acpi_dev);
>      hhc->plug(HOTPLUG_HANDLER(pcms->acpi_dev), dev, &local_err);
> +
> +    /* increment the number of CPUs */
> +    rtc_set_memory(rtc_state, 0x5f, rtc_get_memory(rtc_state, 0x5f) + 1);
looks wrong, what if error happens in plug() handler???

>  out:
>      error_propagate(errp, local_err);
>  }
> diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
> index d8539fd..acfe494 100644
> --- a/include/sysemu/sysemu.h
> +++ b/include/sysemu/sysemu.h
> @@ -183,9 +183,6 @@ void do_pci_device_hot_remove(Monitor *mon, const QDict *qdict);
>  /* generic hotplug */
>  void drive_hot_add(Monitor *mon, const QDict *qdict);
>  
> -/* CPU hotplug */
> -void qemu_register_cpu_added_notifier(Notifier *notifier);
> -
>  /* pcie aer error injection */
>  void pcie_aer_inject_error_print(Monitor *mon, const QObject *data);
>  int do_pcie_aer_inject_error(Monitor *mon,
> diff --git a/qom/cpu.c b/qom/cpu.c
> index b32dd0a..19c5de5 100644
> --- a/qom/cpu.c
> +++ b/qom/cpu.c
> @@ -107,15 +107,6 @@ static void cpu_common_get_memory_mapping(CPUState *cpu,
>      error_setg(errp, "Obtaining memory mappings is unsupported on this CPU.");
>  }
>  
> -/* CPU hot-plug notifiers */
> -static NotifierList cpu_added_notifiers =
> -    NOTIFIER_LIST_INITIALIZER(cpu_add_notifiers);
> -
> -void qemu_register_cpu_added_notifier(Notifier *notifier)
> -{
> -    notifier_list_add(&cpu_added_notifiers, notifier);
> -}
> -
>  void cpu_reset_interrupt(CPUState *cpu, int mask)
>  {
>      cpu->interrupt_request &= ~mask;
> @@ -303,7 +294,6 @@ static void cpu_common_realizefn(DeviceState *dev, Error **errp)
>  
>      if (dev->hotplugged) {
>          cpu_synchronize_post_init(cpu);
> -        notifier_list_notify(&cpu_added_notifiers, dev);
>          cpu_resume(cpu);
>      }
>  }