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

[Richard Henderson <richard.henderson@linaro.org>]

On 2/29/24 17:42, Jinjie Ruan wrote:
> 
> 
> 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.

In my comment against patch 5, that's exactly what I said *not* to do.


r~