Re: [Qemu-devel] [PATCH v2] mttcg: Handle EXCP_ATOMIC exception

[Paolo Bonzini <pbonzini@redhat.com>]

On 02/11/2016 17:40, Pranith Kumar wrote:
> The patch enables handling atomic code in the guest. This should be
> preferably done in cpu_handle_exception(), but the current assumptions
> regarding when we can execute atomic sections cause a deadlock. 
> 
> Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
> ---
>  cpus.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/cpus.c b/cpus.c
> index 8f98060..299ce7e 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -1315,6 +1315,11 @@ static void *qemu_tcg_rr_cpu_thread_fn(void *arg)
>                  if (r == EXCP_DEBUG) {
>                      cpu_handle_guest_debug(cpu);
>                      break;
> +                } else if (r == EXCP_ATOMIC) {
> +                    qemu_mutex_unlock_iothread();
> +                    cpu_exec_step_atomic(cpu);
> +                    qemu_mutex_lock_iothread();
> +                    break;
>                  }
>              } else if (cpu->stop) {
>                  if (cpu->unplug) {
> @@ -1385,6 +1390,10 @@ static void *qemu_tcg_cpu_thread_fn(void *arg)
>                   */
>                  g_assert(cpu->halted);
>                  break;
> +            case EXCP_ATOMIC:
> +                qemu_mutex_unlock_iothread();
> +                cpu_exec_step_atomic(cpu);
> +                qemu_mutex_lock_iothread();
>              default:
>                  /* Ignore everything else? */
>                  break;
> 

Alex, please pick up this patch yourself.

Paolo