Re: [Qemu-devel] [RFC v4 29/71] cpu-exec: convert to cpu_halted

[Alex Bennée]

Emilio G. Cota <address@hidden> writes:

> Signed-off-by: Emilio G. Cota <address@hidden>
> ---
>  accel/tcg/cpu-exec.c | 24 ++++++++++++++++++++----
>  1 file changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
> index 870027d435..f37c9b1e94 100644
> --- a/accel/tcg/cpu-exec.c
> +++ b/accel/tcg/cpu-exec.c
> @@ -422,14 +422,20 @@ static inline TranslationBlock *tb_find(CPUState *cpu,
>      return tb;
>  }
>
> -static inline bool cpu_handle_halt(CPUState *cpu)
> +static inline bool cpu_handle_halt_locked(CPUState *cpu)
>  {
> -    if (cpu->halted) {
> +    g_assert(cpu_mutex_locked(cpu));
> +
> +    if (cpu_halted(cpu)) {
>  #if defined(TARGET_I386) && !defined(CONFIG_USER_ONLY)
>          if ((cpu->interrupt_request & CPU_INTERRUPT_POLL)
>              && replay_interrupt()) {
>              X86CPU *x86_cpu = X86_CPU(cpu);
> +
> +            cpu_mutex_unlock(cpu);
>              qemu_mutex_lock_iothread();
> +            cpu_mutex_lock(cpu);
> +

I think we need a comment or reference to the locking rules for this
case here.

>              apic_poll_irq(x86_cpu->apic_state);
>              cpu_reset_interrupt(cpu, CPU_INTERRUPT_POLL);
>              qemu_mutex_unlock_iothread();
> @@ -439,12 +445,22 @@ static inline bool cpu_handle_halt(CPUState *cpu)
>              return true;
>          }
>
> -        cpu->halted = 0;
> +        cpu_halted_set(cpu, 0);
>      }
>
>      return false;
>  }
>
> +static inline bool cpu_handle_halt(CPUState *cpu)
> +{
> +    bool ret;
> +
> +    cpu_mutex_lock(cpu);
> +    ret = cpu_handle_halt_locked(cpu);
> +    cpu_mutex_unlock(cpu);
> +    return ret;
> +}
> +
>  static inline void cpu_handle_debug_exception(CPUState *cpu)
>  {
>      CPUClass *cc = CPU_GET_CLASS(cpu);
> @@ -543,7 +559,7 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
>          } else if (interrupt_request & CPU_INTERRUPT_HALT) {
>              replay_interrupt();
>              cpu->interrupt_request &= ~CPU_INTERRUPT_HALT;
> -            cpu->halted = 1;
> +            cpu_halted_set(cpu, 1);
>              cpu->exception_index = EXCP_HLT;
>              qemu_mutex_unlock_iothread();
>              return true;


--
Alex Bennée