[PATCH 5.7 054/204] irqchip/gic-v4.1: Ensure accessing the correct RD when writing INVALLR

Greg Kroah-Hartman
2020-08-20T09:37:54Z

From: Zenghui Yu <yuzenghui@huawei.com>

commit 3af9571cd585efafc2facbd8dbd407317ff898cf upstream.

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")
Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200720092328.708-1-yuzenghui@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/irqchip/irq-gic-v3-its.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -3974,18 +3974,22 @@ static void its_vpe_4_1_deschedule(struc
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)