Re: [Qemu-devel] [PATCH RFC qom-cpu] linux-user: Avoid conditional cpu_reset()

[Eduardo Habkost]

On Wed, Jul 10, 2013 at 06:30:38PM +0200, Andreas Färber wrote:
> Some CPUs reset as part of cpu_init(), some others were reset
> afterwards, some not at all. While some targets didn't implement a
> cpu_[state_]reset() function, QOM cpu_reset() is always available.
> There's nothing wrong with resetting twice on startup, so drop
> the #ifdef.
> 
> Suggested-by: Peter Maydell <address@hidden>
> Signed-off-by: Andreas Färber <address@hidden>
> Cc: Eduardo Habkost <address@hidden>
> ---
>  This had been discussed as a possible cleanup for the #ifdef.
>  I am uncertain whether we should do this since it hides the TODO item 
>  of investigating ppc and sparc CPU reset.
> 
>  linux-user/main.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/linux-user/main.c b/linux-user/main.c
> index 7f15d3d..e904d8c 100644
> --- a/linux-user/main.c
> +++ b/linux-user/main.c
> @@ -3637,9 +3637,7 @@ int main(int argc, char **argv, char **envp)
>          fprintf(stderr, "Unable to find CPU definition\n");
>          exit(1);
>      }
> -#if defined(TARGET_SPARC) || defined(TARGET_PPC)
>      cpu_reset(ENV_GET_CPU(env));
> -#endif

Most of the cpu_reset() implementations I have looked at (including
sparc) contain something like:

    memset(env, 0, offsetof(CPUXXXState, breakpoints));

Isn't this clearing userspace registers that are not supposed to be
touched by clone()?

-- 
Eduardo