The GICv2 specification says that reserved register addresses
must RAZ/WI; now that we implement external abort handling
for Arm CPUs this means we must return MEMTX_OK rather than
MEMTX_ERROR, to avoid generating a spurious guest data abort.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 hw/intc/arm_gic.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/hw/intc/arm_gic.c b/hw/intc/arm_gic.c
index 5a0e2a3..d701e49 100644
--- a/hw/intc/arm_gic.c
+++ b/hw/intc/arm_gic.c
@@ -1261,7 +1261,8 @@ static MemTxResult gic_cpu_read(GICState *s, int cpu, int offset,
     default:
         qemu_log_mask(LOG_GUEST_ERROR,
                       "gic_cpu_read: Bad offset %x\n", (int)offset);
-        return MEMTX_ERROR;
+        *data = 0;
+        break;
     }
     return MEMTX_OK;
 }
@@ -1329,7 +1330,7 @@ static MemTxResult gic_cpu_write(GICState *s, int cpu, int offset,
     default:
         qemu_log_mask(LOG_GUEST_ERROR,
                       "gic_cpu_write: Bad offset %x\n", (int)offset);
-        return MEMTX_ERROR;
+        return MEMTX_OK;
     }
     gic_update(s);
     return MEMTX_OK;
-- 
2.7.4

On Wed, Dec 13, 2017 at 8:52 AM, Peter Maydell <peter.maydell@linaro.org> wrote:
> The GICv2 specification says that reserved register addresses
> must RAZ/WI; now that we implement external abort handling
> for Arm CPUs this means we must return MEMTX_OK rather than
> MEMTX_ERROR, to avoid generating a spurious guest data abort.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Looks good to me.

Reviewed-by: Alistair Francis <alistair.francis@xilinx.com>

Alistair


> ---
>  hw/intc/arm_gic.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/hw/intc/arm_gic.c b/hw/intc/arm_gic.c
> index 5a0e2a3..d701e49 100644
> --- a/hw/intc/arm_gic.c
> +++ b/hw/intc/arm_gic.c
> @@ -1261,7 +1261,8 @@ static MemTxResult gic_cpu_read(GICState *s, int cpu, int offset,
>      default:
>          qemu_log_mask(LOG_GUEST_ERROR,
>                        "gic_cpu_read: Bad offset %x\n", (int)offset);
> -        return MEMTX_ERROR;
> +        *data = 0;
> +        break;
>      }
>      return MEMTX_OK;
>  }
> @@ -1329,7 +1330,7 @@ static MemTxResult gic_cpu_write(GICState *s, int cpu, int offset,
>      default:
>          qemu_log_mask(LOG_GUEST_ERROR,
>                        "gic_cpu_write: Bad offset %x\n", (int)offset);
> -        return MEMTX_ERROR;
> +        return MEMTX_OK;
>      }
>      gic_update(s);
>      return MEMTX_OK;
> --
> 2.7.4
>
>