Re: [Qemu-ppc] [Qemu-devel] [PATCH 4/4] ppc: remove excessive logging

[Peter Maydell]

On 11 July 2014 16:18, Joakim Tjernlund <address@hidden> wrote:
> ppc logs every type of Invalid instruction. This generates a lot
> of garbage on console when sshd/ssh_keygen executes as
> they try various insn to optimize its performance.
> The invalid operation log is still there so an unknown insn
> will still be logged.
>
> Signed-off-by: Joakim Tjernlund <address@hidden>
> ---
>  linux-user/main.c | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/linux-user/main.c b/linux-user/main.c
> index b453a39..71a33c7 100644
> --- a/linux-user/main.c
> +++ b/linux-user/main.c
> @@ -1698,7 +1698,6 @@ void cpu_loop(CPUPPCState *env)
>                  }
>                  break;
>              case POWERPC_EXCP_INVAL:
> -                EXCP_DUMP(env, "Invalid instruction\n");
>                  info.si_signo = TARGET_SIGILL;
>                  info.si_errno = 0;
>                  switch (env->error_code & 0xF) {

Rather than just deleting this EXCP_DUMP, I would suggest
changing the EXCP_DUMP macro so  it only does anything
if the user has passed the "-d int" debug logging flag:

#define EXCP_DUMP(env, fmt, ...)                                        \
do {                                                                    \
    CPUState *cs = ENV_GET_CPU(env);                                    \
    qemu_log_mask(CPU_LOG_INT, fmt, ## __VA_ARGS__);                    \
    log_cpu_state_mask(CPU_LOG_INT, cs, 0);                             \
} while (0)

(untested code!). Some applications (like QEMU itself!)
use SIGSEGV as well as SIGILL intentionally, for instance.

(cc'd qemu-ppc to see if they have an opinion.)

thanks
-- PMM