Re: [PATCH 4/8] accel/tcg: introduce tcg_kick_vcpu_thread

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

On 8/9/25 04:59, Paolo Bonzini wrote:
> +void tcg_kick_vcpu_thread(CPUState *cpu)
> +{
> +    /*
> +     * Ensure cpu_exec will see the reason why the exit request was set.
> +     * FIXME: this is not always needed.  Other accelerators instead
> +     * read interrupt_request and set exit_request on demand from the
> +     * CPU thread; see kvm_arch_pre_run() for example.
> +     */
> +    qatomic_store_release(&cpu->exit_request, 1);
> +
> +    /* Ensure cpu_exec will see the exit request after TCG has exited.  */
> +    qatomic_store_release(&cpu->neg.icount_decr.u16.high, -1);
> +}

So, now both cpu_exit and cpu_kick set exit_request.

You ifdef this out again for user-only in patch 7, but this does suggest that kick and 
exit are essentially interchangeable.  You rearrange things a bit in patch 6, but it's 
still not clear to me what the difference between the two should be.  There's certainly 
nothing at all in include/hw/core/cpu.h to differentiate them.

Should we instead eliminate one of kick or exit, unifying the paths?


r~