Re: [PATCH v3 1/4] hw/intc: Remove loongarch_ipi.c

[Jiaxun Yang]

在2024年7月1日七月 上午8:22，maobibo写道：
> On 2024/7/1 下午3:01, Jiaxun Yang wrote:
>> 
>> 
>> 在2024年7月1日七月 上午7:44，maobibo写道：
>>> Also this patch is problematic on LoongArch.
>>>
>>> The original patch is to search physical cpuid rather than logic cpuid.
>>>
>>> We want to make ipi module better and better, however now it comes back
>>> to initial state at the beginning :(
>> 
>> Isn't arch_id the "physical id" you want? "cs->cpu_index" is the logical ID
>> for QEMU.
>> 
>> arch_id is setup by arch code, like APIC ID for x86.
>> 
>> I had come across the old ipi_getcpu  implementation, and I'm sure we were
>> looking at arch_id as well.
> So, where is implementation code for function get_arch_id() looking for 
> vcpu with physical index?

Hi Bibo,

cpu_by_arch_id will be redirected to:

```
CPUState *cpu_by_arch_id(int64_t id)
{
    CPUState *cpu;

    CPU_FOREACH(cpu) {
        CPUClass *cc = CPU_GET_CLASS(cpu);

        if (cc->get_arch_id(cpu) == id) {
            return cpu;
        }
    }
    return NULL;
}
```

It iterates over all vcpus and return CPUStates with corresponding arch_id.

Whereas, for LoongArch's get_arch_id implementation:
```
static int64_t loongarch_cpu_get_arch_id(CPUState *cs)
{
    LoongArchCPU *cpu = LOONGARCH_CPU(cs);

    return cpu->phy_id;
}
```
I believe it matches our intension here.

Thanks

>
> Regards
> Bibo Mao
>
>> 
>> Thanks
>> - Jiaxun
>>>
>>> commit 03ca348b6b9038ce284916b36c19f700ac0ce7a6
>>> Author: Jiaxun Yang <jiaxun.yang@flygoat.com>
>>> Date:   Wed Jun 5 10:04:27 2024
>>>
>>>       hw/intc/loongson_ipi: Replace ipi_getcpu with cpu_by_arch_id
>>>
>>>       cpu_by_arch_id is doing the same thing as our ipi_getcpu logic.
>>>
>>>       Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
>>>       Reviewed-by: Song Gao <gaosong@loongson.cn>
>>>       Message-ID: <20240605-loongson3-ipi-v3-4-ddd2c0e03fa3@flygoat.com>
>>>       Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>>>
>>>
>>> Regards
>>> Bibo Mao
>>>

-- 
- Jiaxun