2020-02-14 14:59:24

by Marc Zyngier

Subject: [PATCH v4 01/20] irqchip/gic-v4.1: Skip absent CPUs while iterating over redistributors

In a system that is only sparsly populated with CPUs, we can end-up with
redistributors structures that are not initialized. Let's make sure we
don't try and access those when iterating over them (in this case when
checking we have a L2 VPE table).

Fixes: 4e6437f12d6e ("irqchip/gic-v4.1: Ensure L2 vPE table is allocated at RD level")
Signed-off-by: Marc Zyngier <[email protected]>
---
drivers/irqchip/irq-gic-v3-its.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 83b1186ffcad..da883a691028 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -2452,6 +2452,10 @@ static bool allocate_vpe_l2_table(int cpu, u32 id)
if (!gic_rdists->has_rvpeid)
return true;

+ /* Skip non-present CPUs */
+ if (!base)
+ return true;
+
val = gicr_read_vpropbaser(base + SZ_128K + GICR_VPROPBASER);

esz = FIELD_GET(GICR_VPROPBASER_4_1_ENTRY_SIZE, val) + 1;
--
2.20.1

2020-02-17 09:13:49

by Zenghui Yu

Subject: Re: [PATCH v4 01/20] irqchip/gic-v4.1: Skip absent CPUs while iterating over redistributors

Hi Marc,

On 2020/2/14 22:57, Marc Zyngier wrote:
> In a system that is only sparsly populated with CPUs, we can end-up with
> redistributors structures that are not initialized. Let's make sure we
> don't try and access those when iterating over them (in this case when
> checking we have a L2 VPE table).
>
> Fixes: 4e6437f12d6e ("irqchip/gic-v4.1: Ensure L2 vPE table is allocated at RD level")
> Signed-off-by: Marc Zyngier <[email protected]>
> ---
> drivers/irqchip/irq-gic-v3-its.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index 83b1186ffcad..da883a691028 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -2452,6 +2452,10 @@ static bool allocate_vpe_l2_table(int cpu, u32 id)
> if (!gic_rdists->has_rvpeid)
> return true;
>
> + /* Skip non-present CPUs */
> + if (!base)
> + return true;
> +

Thanks for fixing this,

Reviewed-by: Zenghui Yu <[email protected]>

> val = gicr_read_vpropbaser(base + SZ_128K + GICR_VPROPBASER);
>
> esz = FIELD_GET(GICR_VPROPBASER_4_1_ENTRY_SIZE, val) + 1;
>