Re: [PATCH v7 5/8] hw/arm/virt: Check CPU type in machine_run_board_init()

[Gavin Shan <gshan@redhat.com>]

On 11/27/23 21:13, Marcin Juszkiewicz wrote:
> W dniu 27.11.2023 o 00:12, Gavin Shan pisze:
>> @@ -2939,6 +2900,28 @@ static void virt_machine_class_init(ObjectClass *oc, void *data)
>>   {
>>       MachineClass *mc = MACHINE_CLASS(oc);
>>       HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(oc);
>> +    static const char * const valid_cpu_types[] = {
>> +#ifdef CONFIG_TCG
>> +        ARM_CPU_TYPE_NAME("cortex-a7"),
>> +        ARM_CPU_TYPE_NAME("cortex-a15"),
>> +        ARM_CPU_TYPE_NAME("cortex-a35"),
>> +        ARM_CPU_TYPE_NAME("cortex-a55"),
>> +        ARM_CPU_TYPE_NAME("cortex-a72"),
>> +        ARM_CPU_TYPE_NAME("cortex-a76"),
>> +        ARM_CPU_TYPE_NAME("cortex-a710"),
>> +        ARM_CPU_TYPE_NAME("a64fx"),
>> +        ARM_CPU_TYPE_NAME("neoverse-n1"),
>> +        ARM_CPU_TYPE_NAME("neoverse-v1"),
>> +        ARM_CPU_TYPE_NAME("neoverse-n2"),
>> +#endif
>> +        ARM_CPU_TYPE_NAME("cortex-a53"),
>> +        ARM_CPU_TYPE_NAME("cortex-a57"),
>> +#if defined(CONFIG_KVM) || defined(CONFIG_HVF)
>> +        ARM_CPU_TYPE_NAME("host"),
>> +#endif
>> +        ARM_CPU_TYPE_NAME("max"),
>> +        NULL
>> +    };
> 
> I understand that you just move list from one place to the other but also wonder why a53/a57 were/are outside of 'ifdef CONFIG_TCG' check.
> 

I'm not sure about HVF, but a53/a57 can be supported by KVM. The supported list of
CPUs by KVM is defined in linux/arch/arm64/include/uapi/asm/kvm.h as below

/*
  * Supported CPU Targets - Adding a new target type is not recommended,
  * unless there are some special registers not supported by the
  * genericv8 syreg table.
  */
#define KVM_ARM_TARGET_AEM_V8           0
#define KVM_ARM_TARGET_FOUNDATION_V8    1
#define KVM_ARM_TARGET_CORTEX_A57       2
#define KVM_ARM_TARGET_XGENE_POTENZA    3
#define KVM_ARM_TARGET_CORTEX_A53       4
/* Generic ARM v8 target */
#define KVM_ARM_TARGET_GENERIC_V8       5

#define KVM_ARM_NUM_TARGETS             6

And the following QEMU commit gives more hints about it.

[gshan@gshan q]$ git show 39920a04952
commit 39920a04952b67fb1fce8fc3519ac18b7a95f3f3
Author: Fabiano Rosas <farosas@suse.de>
Date:   Wed Apr 26 15:00:05 2023 -0300

     target/arm: Move 64-bit TCG CPUs into tcg/
     
     Move the 64-bit CPUs that are TCG-only:
     - cortex-a35
     - cortex-a55
     - cortex-a72
     - cortex-a76
     - a64fx
     - neoverse-n1
     
     Keep the CPUs that can be used with KVM:
     - cortex-a57
     - cortex-a53
     - max
     - host
     
     Signed-off-by: Fabiano Rosas <farosas@suse.de>
     Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
     Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
     Message-id: 20230426180013.14814-6-farosas@suse.de
     Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Thanks,
Gavin