Re: [Qemu-devel] [PATCH 2/3] hw/intc/arm_gicv3_cpuif: Don't let BPR be set below its minimum

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

On 04/26/2017 02:13 PM, Peter Maydell wrote:
> icc_bpr_write() was not enforcing that writing a value below the
> minimum for the BPR should behave as if the BPR was set to the
> minimum value. This doesn't make a difference for the secure
> BPRs (since we define the minimum for the QEMU implementation
> as zero) but did mean we were allowing the NS BPR1 to be set to
> 0 when 1 should be the lowest value.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  hw/intc/arm_gicv3_cpuif.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/hw/intc/arm_gicv3_cpuif.c b/hw/intc/arm_gicv3_cpuif.c
> index d31eba0..e660b3f 100644
> --- a/hw/intc/arm_gicv3_cpuif.c
> +++ b/hw/intc/arm_gicv3_cpuif.c
> @@ -1388,6 +1388,7 @@ static void icc_bpr_write(CPUARMState *env, const ARMCPRegInfo *ri,
>  {
>      GICv3CPUState *cs = icc_cs_from_env(env);
>      int grp = (ri->crm == 8) ? GICV3_G0 : GICV3_G1;
> +    uint64_t minval;
>
>      if (icv_access(env, grp == GICV3_G0 ? HCR_FMO : HCR_IMO)) {
>          icv_bpr_write(env, ri, value);
> @@ -1415,6 +1416,11 @@ static void icc_bpr_write(CPUARMState *env, const ARMCPRegInfo *ri,
>          return;
>      }
>
> +    minval = (grp == GICV3_G1NS) ? GIC_MIN_BPR_NS : GIC_MIN_BPR;
> +    if (value < minval) {
> +        value = minval;
> +    }
> +

which is:

     if (grp == GICV3_G1NS) {
         value = MAX(value, GIC_MIN_BPR_NS);
     }

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

>      cs->icc_bpr[grp] = value & 7;
>      gicv3_cpuif_update(cs);
>  }
>