Re: [RFC PATCH v9 04/23] target/arm: Implement ALLINT MSR (immediate)

[Peter Maydell <peter.maydell@linaro.org>]

On Thu, 21 Mar 2024 at 13:10, Jinjie Ruan <ruanjinjie@huawei.com> wrote:
>
> Add ALLINT MSR (immediate) to decodetree, in which the CRm is 0b000x. The
> EL0 check is necessary to ALLINT, and the EL1 check is necessary when
> imm == 1. So implement it inline for EL2/3, or EL1 with imm==0. Avoid the
> unconditional write to pc and use raise_exception_ra to unwind.

> +void HELPER(msr_set_allint_el1)(CPUARMState *env)
> +{
> +    /* ALLINT update to PSTATE. */
> +    if (arm_hcrx_el2_eff(env) & HCRX_TALLINT) {
> +        raise_exception_ra(env, EXCP_UDEF,
> +                           syn_aa64_sysregtrap(0, 1, 0, 4, 1, 0x1f, 0),
> +                           exception_target_el(env), GETPC());
> +    }
> +
> +    env->pstate |= PSTATE_ALLINT;
> +}

This is a hypervisor trap from EL1 to EL2, so the target_el
argument to raise_exception_ra() should be "2", not
"exception_target_el(env)". Otherwise we will trap to EL1.

thanks
-- PMM