irqchip/gic-v3-its: Fix get_vlpi_map() breakage with doorbells

When updating an LPI configuration, get_vlpi_map() may be passed a
irq_data structure relative to an ITS domain (the normal case) or one
that is relative to the core GICv3 domain in the case of a GICv4
doorbell.

In the latter case, special care must be take not to dereference
the irq_chip data as an its_dev structure, as that isn't what is
stored there. Instead, check *first* whether the IRQ is forwarded
to a vcpu, and only then try to obtain the vlpi mapping.

Fixes: 3638a0e84996 ("irqchip/gic-v3-its: Add its_vlpi_map helpers")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reported-by: Zenghui Yu <yuzenghui@huawei.com>
Link: https://lore.kernel.org/r/20200122085609.658-1-yuzenghui@huawei.com

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index e05673bcd52bdad6adff75c48140baaeea1a79c1..b704214390c0fbe3d81302a7d367bce5231ea388 100644 (file)
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -1170,13 +1170,14 @@ static void its_send_vclear(struct its_device *dev, u32 event_id)
  */
 static struct its_vlpi_map *get_vlpi_map(struct irq_data *d)
 {
-       struct its_device *its_dev = irq_data_get_irq_chip_data(d);
-       u32 event = its_get_event_id(d);
+       if (irqd_is_forwarded_to_vcpu(d)) {
+               struct its_device *its_dev = irq_data_get_irq_chip_data(d);
+               u32 event = its_get_event_id(d);
 
-       if (!irqd_is_forwarded_to_vcpu(d))
-               return NULL;
+               return dev_event_to_vlpi_map(its_dev, event);
+       }
 
-       return dev_event_to_vlpi_map(its_dev, event);
+       return NULL;
 }
 
 static void lpi_write_config(struct irq_data *d, u8 clr, u8 set)