Re: [RFC PATCH v5 12/22] target/arm: Handle NMI in arm_cpu_do_interrupt_aarch64()

[Jinjie Ruan]

On 2024/3/1 7:09, Richard Henderson wrote:
> On 2/29/24 03:10, Jinjie Ruan via wrote:
>> According to Arm GIC section 4.6.3 Interrupt superpriority, the interrupt
>> with superpriority is always IRQ, never FIQ, so the NMI exception trap
>> entry
>> behave like IRQ. However, VNMI can be IRQ or FIQ, FIQ can only come from
>> hcrx_el2.HCRX_VFNMI bit, IRQ can be raised from the GIC or come from the
>> hcrx_el2.HCRX_VINMI bit.
>>
>> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
>> ---
>> v4:
>> - Also handle VNMI in arm_cpu_do_interrupt_aarch64().
>> v3:
>> - Remove the FIQ NMI handle.
>> ---
>>   target/arm/helper.c | 9 +++++++++
>>   1 file changed, 9 insertions(+)
>>
>> diff --git a/target/arm/helper.c b/target/arm/helper.c
>> index b796dbdf21..bd34b3506a 100644
>> --- a/target/arm/helper.c
>> +++ b/target/arm/helper.c
>> @@ -11459,12 +11459,21 @@ static void
>> arm_cpu_do_interrupt_aarch64(CPUState *cs)
>>           break;
>>       case EXCP_IRQ:
>>       case EXCP_VIRQ:
>> +    case EXCP_NMI:
>>           addr += 0x80;
>>           break;
>>       case EXCP_FIQ:
>>       case EXCP_VFIQ:
>>           addr += 0x100;
>>           break;
>> +    case EXCP_VNMI:
>> +        if (env->irq_line_state & CPU_INTERRUPT_VNMI ||
>> +            env->cp15.hcrx_el2 & HCRX_VINMI) {
>> +            addr += 0x80;
>> +        } else if (env->cp15.hcrx_el2 & HCRX_VFNMI) {
>> +            addr += 0x100;
>> +        }
>> +        break;
> 
> By not combining VFNMI with CPU_INTERRUPT_VNMI, you don't need this
> complication.
> Just
> 
>      case EXCP_IRQ:
>      case EXCP_VIRQ:
> +    case EXCP_NMI:

Not understand it. both VIRQ and VFIQ will set CPU_INTERRUPT_VNMI and
cause EXCP_VNMI if they have Superpriority, the distinction jump here is
necessary.

> 
> 
> r~