Re: [Qemu-devel] [PATCH v1] cpu-exec: fix missed CPU kick during interrupt injection

[David Hildenbrand]

> atomic_mb_set can be a little faster on x86, so:
> 
> diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
> index dfba5ebd29..4452cd9856 100644
> --- a/accel/tcg/cpu-exec.c
> +++ b/accel/tcg/cpu-exec.c
> @@ -528,12 +528,10 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
>  
>      /* Clear the interrupt flag now since we're processing
>       * cpu->interrupt_request and cpu->exit_request.
> +     * Ensure zeroing happens before reading cpu->exit_request or
> +     * cpu->interrupt_request (see also smp_wmb in cpu_exit())
>       */
> -    atomic_set(&cpu->icount_decr.u16.high, 0);
> -    /* Ensure zeroing happens before reading cpu->exit_request or
> -     * cpu->interrupt_request. (also see cpu_exit())
> -     */
> -    smp_mb();
> +    atomic_mb_set(&cpu->icount_decr.u16.high, 0);
>  
>      if (unlikely(atomic_read(&cpu->interrupt_request))) {
>          int interrupt_request;
> 

Looks good to me! Thanks!


-- 

Thanks,

David / dhildenb