Re: [Qemu-devel] [PATCH v2 2/2] target/lm32: hold BQL in gdbstub

[Peter Maydell]

On 21 May 2018 at 13:21, Michael Walle <address@hidden> wrote:
> Changing the IP/IM registers may cause interrupts, so hold the BQL.
>
> Cc: address@hidden
> Signed-off-by: Michael Walle <address@hidden>
> ---
>  target/lm32/gdbstub.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/target/lm32/gdbstub.c b/target/lm32/gdbstub.c
> index cf929dd392..dac9418a2b 100644
> --- a/target/lm32/gdbstub.c
> +++ b/target/lm32/gdbstub.c
> @@ -18,6 +18,7 @@
>   * License along with this library; if not, see 
> <http://www.gnu.org/licenses/>.
>   */
>  #include "qemu/osdep.h"
> +#include "qemu/main-loop.h"
>  #include "qemu-common.h"
>  #include "cpu.h"
>  #include "exec/gdbstub.h"
> @@ -82,10 +83,14 @@ int lm32_cpu_gdb_write_register(CPUState *cs, uint8_t 
> *mem_buf, int n)
>              env->ie = tmp;
>              break;
>          case 37:
> +            qemu_mutex_lock_iothread();
>              lm32_pic_set_im(env->pic_state, tmp);
> +            qemu_mutex_unlock_iothread();
>              break;
>          case 38:
> +            qemu_mutex_lock_iothread();
>              lm32_pic_set_ip(env->pic_state, tmp);
> +            qemu_mutex_unlock_iothread();
>              break;
>          }
>      }

Are you sure this is necessary? I would have expected the gdbstub to
be operating under the qemu lock anyway.

thanks
-- PMM