1 files changed, 48 insertions, 8 deletions

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index da883a691028..1af713990123 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -239,15 +239,41 @@ static struct its_vlpi_map *get_vlpi_map(struct irq_data *d)
 	return NULL;
 }
 
-static int irq_to_cpuid(struct irq_data *d)
+static int vpe_to_cpuid_lock(struct its_vpe *vpe, unsigned long *flags)
+{
+	raw_spin_lock_irqsave(&vpe->vpe_lock, *flags);
+	return vpe->col_idx;
+}
+
+static void vpe_to_cpuid_unlock(struct its_vpe *vpe, unsigned long flags)
+{
+	raw_spin_unlock_irqrestore(&vpe->vpe_lock, flags);
+}
+
+static int irq_to_cpuid_lock(struct irq_data *d, unsigned long *flags)
 {
-	struct its_device *its_dev = irq_data_get_irq_chip_data(d);
 	struct its_vlpi_map *map = get_vlpi_map(d);
+	int cpu;
 
-	if (map)
-		return map->vpe->col_idx;
+	if (map) {
+		cpu = vpe_to_cpuid_lock(map->vpe, flags);
+	} else {
+		/* Physical LPIs are already locked via the irq_desc lock */
+		struct its_device *its_dev = irq_data_get_irq_chip_data(d);
+		cpu = its_dev->event_map.col_map[its_get_event_id(d)];
+		/* Keep GCC quiet... */
+		*flags = 0;
+	}
 
-	return its_dev->event_map.col_map[its_get_event_id(d)];
+	return cpu;
+}
+
+static void irq_to_cpuid_unlock(struct irq_data *d, unsigned long flags)
+{
+	struct its_vlpi_map *map = get_vlpi_map(d);
+
+	if (map)
+		vpe_to_cpuid_unlock(map->vpe, flags);
 }
 
 static struct its_collection *valid_col(struct its_collection *col)
@@ -1329,7 +1355,9 @@ static void direct_lpi_inv(struct irq_data *d)
 {
 	struct its_vlpi_map *map = get_vlpi_map(d);
 	void __iomem *rdbase;
+	unsigned long flags;
 	u64 val;
+	int cpu;
 
 	if (map) {
 		struct its_device *its_dev = irq_data_get_irq_chip_data(d);
@@ -1344,10 +1372,12 @@ static void direct_lpi_inv(struct irq_data *d)
 	}
 
 	/* Target the redistributor this LPI is currently routed to */
-	rdbase = per_cpu_ptr(gic_rdists->rdist, irq_to_cpuid(d))->rd_base;
+	cpu = irq_to_cpuid_lock(d, &flags);
+	rdbase = per_cpu_ptr(gic_rdists->rdist, cpu)->rd_base;
 	gic_write_lpir(val, rdbase + GICR_INVLPIR);
 
 	wait_for_syncr(rdbase);
+	irq_to_cpuid_unlock(d, flags);
 }
 
 static void lpi_update_config(struct irq_data *d, u8 clr, u8 set)
@@ -3486,17 +3516,25 @@ static int its_vpe_set_affinity(struct irq_data *d,
 {
 	struct its_vpe *vpe = irq_data_get_irq_chip_data(d);
 	int from, cpu = cpumask_first(mask_val);
+	unsigned long flags;
 
 	/*
 	 * Changing affinity is mega expensive, so let's be as lazy as
 	 * we can and only do it if we really have to. Also, if mapped
 	 * into the proxy device, we need to move the doorbell
 	 * interrupt to its new location.
+	 *
+	 * Another thing is that changing the affinity of a vPE affects
+	 * *other interrupts* such as all the vLPIs that are routed to
+	 * this vPE. This means that the irq_desc lock is not enough to
+	 * protect us, and that we must ensure nobody samples vpe->col_idx
+	 * during the update, hence the lock below which must also be
+	 * taken on any vLPI handling path that evaluates vpe->col_idx.
 	 */
-	if (vpe->col_idx == cpu)
+	from = vpe_to_cpuid_lock(vpe, &flags);
+	if (from == cpu)
 		goto out;
 
-	from = vpe->col_idx;
 	vpe->col_idx = cpu;
 
 	/*
@@ -3512,6 +3550,7 @@ static int its_vpe_set_affinity(struct irq_data *d,
 
 out:
 	irq_data_update_effective_affinity(d, cpumask_of(cpu));
+	vpe_to_cpuid_unlock(vpe, flags);
 
 	return IRQ_SET_MASK_OK_DONE;
 }
@@ -3855,6 +3894,7 @@ static int its_vpe_init(struct its_vpe *vpe)
 		return -ENOMEM;
 	}
 
+	raw_spin_lock_init(&vpe->vpe_lock);
 	vpe->vpe_id = vpe_id;
 	vpe->vpt_page = vpt_page;
 	if (gic_rdists->has_rvpeid)