Re: [RFC PATCH v8 05/23] target/arm: Support MSR access to ALLINT

[Jinjie Ruan via <qemu-devel@nongnu.org>]

On 2024/3/20 1:30, Peter Maydell wrote:
> On Mon, 18 Mar 2024 at 09:37, Jinjie Ruan <ruanjinjie@huawei.com> wrote:
>>
>> Support ALLINT msr access as follow:
>>         mrs <xt>, ALLINT        // read allint
>>         msr ALLINT, <xt>        // write allint with imm
>>
>> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
>> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
>> ---
>> v5:
>> - Add Reviewed-by.
>> v4:
>> - Remove arm_is_el2_enabled() check in allint_check().
>> - Change to env->pstate instead of env->allint.
>> v3:
>> - Remove EL0 check in aa64_allint_access() which alreay checks in .access
>>   PL1_RW.
>> - Use arm_hcrx_el2_eff() in aa64_allint_access() instead of env->cp15.hcrx_el2.
>> - Make ALLINT msr access function controlled by aa64_nmi.
>> ---
>>  target/arm/helper.c | 34 ++++++++++++++++++++++++++++++++++
>>  1 file changed, 34 insertions(+)
>>
>> diff --git a/target/arm/helper.c b/target/arm/helper.c
>> index b19a0178ce..aa0151c775 100644
>> --- a/target/arm/helper.c
>> +++ b/target/arm/helper.c
>> @@ -4752,6 +4752,36 @@ static void aa64_daif_write(CPUARMState *env, const ARMCPRegInfo *ri,
>>      env->daif = value & PSTATE_DAIF;
>>  }
>>
>> +static void aa64_allint_write(CPUARMState *env, const ARMCPRegInfo *ri,
>> +                              uint64_t value)
>> +{
>> +    env->pstate = (env->pstate & ~PSTATE_ALLINT) | (value & PSTATE_ALLINT);
>> +}
>> +
>> +static uint64_t aa64_allint_read(CPUARMState *env, const ARMCPRegInfo *ri)
>> +{
>> +    return env->pstate & PSTATE_ALLINT;
>> +}
>> +
>> +static CPAccessResult aa64_allint_access(CPUARMState *env,
>> +                                         const ARMCPRegInfo *ri, bool isread)
>> +{
>> +    if (arm_current_el(env) == 1 && (arm_hcrx_el2_eff(env) & HCRX_TALLINT)) {
>> +        return CP_ACCESS_TRAP_EL2;
>> +    }
>> +    return CP_ACCESS_OK;
> 
> Forgot to note in my earlier email: HCRX_EL2.TALLINT traps
> only writes to ALLINT, not reads, so the condition
> here needs to also look at 'isread'.

Thank you! I'll fix it.

> 
>> +}
> 
> thanks
> -- PMM