Re: [Qemu-devel] [RFC PATCH v4 11/25] cpu-exec: allow temporary disabling icount

["Pavel Dovgaluk" <Pavel.Dovgaluk@ispras.ru>]

> From: Paolo Bonzini [mailto:paolo.bonzini@gmail.com] On Behalf Of Paolo Bonzini
> On 07/11/2014 11:32, Pavel Dovgalyuk wrote:
> >          cpu_restore_state_from_tb(cpu, tb, retaddr);
> > +        /* tb could be temporary, generated by exec nocache */
> > +        tb_phys_invalidate(tb, -1);
> 
> Would you need to do the same sequence as cpu_exec_nocache in this case?

Right.

>     cpu->current_tb = NULL;
>     tb_phys_invalidate(tb, -1);
>     tb_free(tb);
> 
> In this case, perhaps something like this would be better:
> 
> diff --git a/cpu-exec.c b/cpu-exec.c
> index 10c0f42..faf8041 100644
> --- a/cpu-exec.c
> +++ b/cpu-exec.c
> @@ -209,7 +209,7 @@ static void cpu_exec_nocache(CPUArchState *env, int max_cycles,
>          max_cycles = CF_COUNT_MASK;
> 
>      tb = tb_gen_code(cpu, orig_tb->pc, orig_tb->cs_base, orig_tb->flags,
> -                     max_cycles);
> +                     max_cycles | CF_NOCACHE);
>      cpu->current_tb = tb;
>      /* execute the generated code */
>      trace_exec_tb_nocache(tb, tb->pc);
> diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
> index 9b67d16..41464f3 100644
> --- a/include/exec/exec-all.h
> +++ b/include/exec/exec-all.h
> @@ -148,6 +148,7 @@ struct TranslationBlock {
>  #define CF_COUNT_MASK  0x7fff
>  #define CF_LAST_IO     0x8000 /* Last insn may be an IO access.  */
>  #define CF_LAST_IO     0x8000 /* Last insn may be an IO access.  */
> +#define CF_NOCACHE     0x40000 /* To be freed after execution */
> 
>      void *tc_ptr;    /* pointer to the translated code */
>      /* next matching tb for physical address. */
> diff --git a/translate-all.c b/translate-all.c
> index 1a27df7..6ea4da4 100644
> --- a/translate-all.c
> +++ b/translate-all.c
> @@ -264,6 +264,12 @@ bool cpu_restore_state(CPUState *cpu, uintptr_t retaddr)
>      tb = tb_find_pc(retaddr);
>      if (tb) {
>          cpu_restore_state_from_tb(cpu, tb, retaddr);
> +        if (tb->cflags & CF_NOCACHE) {
> +            /* one-shot translation, invalidate it immediately */
> +            cpu->current_tb = NULL;
> +            tb_phys_invalidate(tb, -1);
> +            tb_free(tb);
> +        }
>          return true;
>      }
>      return false;
> 
> 
> I pushed it to an icount branch on my github repository, together with
> other patches that introduce CF_USE_ICOUNT instead of touching the
> use_icount global variable.  Can you please take a look and, if it
> works, incorporate it in your patch series?

Ok, I'll check it.
I noticed that you missed this patch in your branch: http://lists.nongnu.org/archive/html/qemu-devel/2014-10/msg04034.html

Pavel Dovgalyuk