The GICv4.1 spec tells us that it's CONSTRAINED UNPREDICTABLE to issue a
register-based invalidation operation for a vPEID not mapped to that RD,
or another RD within the same CommonLPIAff group.
To follow this rule, commit f3a059219bc7 ("irqchip/gic-v4.1: Ensure mutual
exclusion between vPE affinity change and RD access") tried to address the
race between the RD accesses and the vPE affinity change, but somehow
forgot to take GICR_INVALLR into account. Let's take the vpe_lock before
evaluating vpe->col_idx to fix it.
Fixes: f3a059219bc7 ("irqchip/gic-v4.1: Ensure mutual exclusion between vPE affinity change and RD access")
Cc: [email protected]
Signed-off-by: Zenghui Yu <[email protected]>
---
* From v1:
- Add a proper Fixes: tag
- Cc stable
drivers/irqchip/irq-gic-v3-its.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index beac4caefad9..5bf2263bdbcc 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -4087,18 +4087,22 @@ static void its_vpe_4_1_deschedule(struct its_vpe *vpe,
static void its_vpe_4_1_invall(struct its_vpe *vpe)
{
void __iomem *rdbase;
+ unsigned long flags;
u64 val;
+ int cpu;
val = GICR_INVALLR_V;
val |= FIELD_PREP(GICR_INVALLR_VPEID, vpe->vpe_id);
/* Target the redistributor this vPE is currently known on */
- raw_spin_lock(&gic_data_rdist_cpu(vpe->col_idx)->rd_lock);
- rdbase = per_cpu_ptr(gic_rdists->rdist, vpe->col_idx)->rd_base;
+ cpu = vpe_to_cpuid_lock(vpe, &flags);
+ raw_spin_lock(&gic_data_rdist_cpu(cpu)->rd_lock);
+ rdbase = per_cpu_ptr(gic_rdists->rdist, cpu)->rd_base;
gic_write_lpir(val, rdbase + GICR_INVALLR);
wait_for_syncr(rdbase);
- raw_spin_unlock(&gic_data_rdist_cpu(vpe->col_idx)->rd_lock);
+ raw_spin_unlock(&gic_data_rdist_cpu(cpu)->rd_lock);
+ vpe_to_cpuid_unlock(vpe, flags);
}
static int its_vpe_4_1_set_vcpu_affinity(struct irq_data *d, void *vcpu_info)
--
2.19.1
On Mon, 20 Jul 2020 17:23:28 +0800, Zenghui Yu wrote:
> The GICv4.1 spec tells us that it's CONSTRAINED UNPREDICTABLE to issue a
> register-based invalidation operation for a vPEID not mapped to that RD,
> or another RD within the same CommonLPIAff group.
>
> To follow this rule, commit f3a059219bc7 ("irqchip/gic-v4.1: Ensure mutual
> exclusion between vPE affinity change and RD access") tried to address the
> race between the RD accesses and the vPE affinity change, but somehow
> forgot to take GICR_INVALLR into account. Let's take the vpe_lock before
> evaluating vpe->col_idx to fix it.
Applied to irq/irqchip-5.9, thanks!
[1/1] irqchip/gic-v4.1: Ensure accessing the correct RD when writing INVALLR
commit: fdccf1d9d10395abfe082f50694f374997c6e101
Cheers,
M.
--
Without deviation from the norm, progress is not possible.