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[2/3] hw/intc/arm_gicv3_cpuif: Don't let BPR be set below its minimum

Message ID 1493226792-3237-3-git-send-email-peter.maydell@linaro.org
State New
Headers show

Commit Message

Peter Maydell April 26, 2017, 5:13 p.m. UTC
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(+)

Comments

Philippe Mathieu-Daudé May 14, 2017, 5:31 a.m. UTC | #1
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);
>  }
>
Peter Maydell May 30, 2017, 9:47 a.m. UTC | #2
On 14 May 2017 at 06:31, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
> On 04/26/2017 02:13 PM, Peter Maydell wrote:
>> +    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);
>     }

Only if you assume GIC_MIN_BPR must always be 0, which isn't
necessarily the case. (One day we might need to update it to
be a per-device configurable parameter, like the VBPR min.)

thanks
-- PMM
diff mbox

Patch

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