Re: [RFC PATCH v2 08/22] target/arm: Handle IS/FS in ISR_EL1 for NMI

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

On 2/21/24 03:08, Jinjie Ruan via wrote:
> Add IS and FS bit in ISR_EL1 and handle the read according to whether the
> NMI is IRQ or FIQ.
> 
> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
> ---
>   target/arm/cpu.h    | 2 ++
>   target/arm/helper.c | 9 +++++++++
>   2 files changed, 11 insertions(+)
> 
> diff --git a/target/arm/cpu.h b/target/arm/cpu.h
> index 051e589e19..e2d07e3312 100644
> --- a/target/arm/cpu.h
> +++ b/target/arm/cpu.h
> @@ -1476,6 +1476,8 @@ FIELD(CPTR_EL3, TCPAC, 31, 1)
>   #define CPSR_N (1U << 31)
>   #define CPSR_NZCV (CPSR_N | CPSR_Z | CPSR_C | CPSR_V)
>   #define CPSR_AIF (CPSR_A | CPSR_I | CPSR_F)
> +#define ISR_FS (1U << 9)
> +#define ISR_IS (1U << 10)
>   
>   #define CPSR_IT (CPSR_IT_0_1 | CPSR_IT_2_7)
>   #define CACHED_CPSR_BITS (CPSR_T | CPSR_AIF | CPSR_GE | CPSR_IT | CPSR_Q \
> diff --git a/target/arm/helper.c b/target/arm/helper.c
> index 0bd7a87e51..62c8e5d611 100644
> --- a/target/arm/helper.c
> +++ b/target/arm/helper.c
> @@ -2022,6 +2022,10 @@ static uint64_t isr_read(CPUARMState *env, const ARMCPRegInfo *ri)
>           if (cs->interrupt_request & CPU_INTERRUPT_HARD) {
>               ret |= CPSR_I;
>           }
> +
> +        if ((cs->interrupt_request & CPU_INTERRUPT_NMI) && env->nmi_is_irq) {
> +            ret |= ISR_IS;
> +        }
>       }
>   
>       if (hcr_el2 & HCR_FMO) {
> @@ -2032,6 +2036,11 @@ static uint64_t isr_read(CPUARMState *env, const ARMCPRegInfo *ri)
>           if (cs->interrupt_request & CPU_INTERRUPT_FIQ) {
>               ret |= CPSR_F;
>           }
> +
> +        if ((cs->interrupt_request & CPU_INTERRUPT_NMI) &&
> +            (!env->nmi_is_irq)) {
> +            ret |= ISR_FS;
> +        }
>       }

The external CPU_INTERRUPT_NMI will never signal FIQ.

With CPU_INTERRUPT_NMI, both CPSR_I and ISR_IS must be set.

Missing is the handling of HCRX_EL2.{VFNMI,VINMI} to signal vFIQ and vIRQ with 
superpriority.  Unless I missed it, I don't see HCRX_EL2 adjusted for FEAT_NMI at all.


r~