Re: [Qemu-devel] [PULL 10/10] cpu-exec: Add "nochain" debug flag

["Edgar E. Iglesias" <edgar.iglesias@gmail.com>]

On Wed, Oct 21, 2015 at 11:42:59AM -1000, Richard Henderson wrote:
> Respect it to avoid linking TBs together.
> 

Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>


> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> ---
>  cpu-exec.c         | 3 ++-
>  include/qemu/log.h | 1 +
>  qemu-log.c         | 3 +++
>  3 files changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/cpu-exec.c b/cpu-exec.c
> index 8fd56a6..7eef083 100644
> --- a/cpu-exec.c
> +++ b/cpu-exec.c
> @@ -477,7 +477,8 @@ int cpu_exec(CPUState *cpu)
>                  /* see if we can patch the calling TB. When the TB
>                     spans two pages, we cannot safely do a direct
>                     jump. */
> -                if (next_tb != 0 && tb->page_addr[1] == -1) {
> +                if (next_tb != 0 && tb->page_addr[1] == -1
> +                    && !qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) {
>                      tb_add_jump((TranslationBlock *)(next_tb & ~TB_EXIT_MASK),
>                                  next_tb & TB_EXIT_MASK, tb);
>                  }
> diff --git a/include/qemu/log.h b/include/qemu/log.h
> index f880e66..7de4500 100644
> --- a/include/qemu/log.h
> +++ b/include/qemu/log.h
> @@ -41,6 +41,7 @@ static inline bool qemu_log_enabled(void)
>  #define LOG_UNIMP          (1 << 10)
>  #define LOG_GUEST_ERROR    (1 << 11)
>  #define CPU_LOG_MMU        (1 << 12)
> +#define CPU_LOG_TB_NOCHAIN (1 << 13)
>  
>  /* Returns true if a bit is set in the current loglevel mask
>   */
> diff --git a/qemu-log.c b/qemu-log.c
> index 13f3813..efd07c8 100644
> --- a/qemu-log.c
> +++ b/qemu-log.c
> @@ -119,6 +119,9 @@ const QEMULogItem qemu_log_items[] = {
>      { LOG_GUEST_ERROR, "guest_errors",
>        "log when the guest OS does something invalid (eg accessing a\n"
>        "non-existent register)" },
> +    { CPU_LOG_TB_NOCHAIN, "nochain",
> +      "do not chain compiled TBs so that \"exec\" and \"cpu\" show\n"
> +      "complete traces" },
>      { 0, NULL, NULL },
>  };
>  
> -- 
> 2.4.3
> 
>