Re: [Qemu-devel] [PULL 07/11] cpu-exec: don't overwrite exception_index

[Peter Maydell]

On 16 November 2017 at 11:59, Paolo Bonzini <address@hidden> wrote:
> From: Pavel Dovgalyuk <address@hidden>
>
> This patch adds a condition before overwriting exception_index fiels.
> It is needed when exception_index is already set to some meaningful value.
>
> Signed-off-by: Pavel Dovgalyuk <address@hidden>
>
> Message-Id: <address@hidden>
> Signed-off-by: Paolo Bonzini <address@hidden>
> ---
>  accel/tcg/cpu-exec.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
> index 61297f8f4a..0473055a08 100644
> --- a/accel/tcg/cpu-exec.c
> +++ b/accel/tcg/cpu-exec.c
> @@ -594,7 +594,9 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
>      if (unlikely(atomic_read(&cpu->exit_request)
>          || (use_icount && cpu->icount_decr.u16.low + cpu->icount_extra == 
> 0))) {
>          atomic_set(&cpu->exit_request, 0);
> -        cpu->exception_index = EXCP_INTERRUPT;
> +        if (cpu->exception_index == -1) {
> +            cpu->exception_index = EXCP_INTERRUPT;
> +        }
>          return true;
>      }

Hi. This commit breaks booting of Debian on aarch64 virt board.
(repro instructions for creating the image available at:
https://translatedcode.wordpress.com/2017/07/24/installing-debian-on-qemus-64-bit-arm-virt-board/)
The guest kernel never prints anything to the serial port.

Reverting this commit fixes master for me, so I plan to do
that on Monday.

thanks
-- PMM