[PATCH v2 1/2] irqchip/gic-v4.1: Fix GICv4.1 doorbell affinity

[Kunkun Jiang]

dd3f050a216e make an optimization, VMOVP can be skipped if moving
VPE to a cpu whose RD is sharing its VPE table with the current one.
But when skipping VMOVP, the affinity recorded in irq_data is still
updated. This causes the doorbell affinity recorfed in the irq_data
to be inconsistent with the actual.

In corner case, this may result in lost interrupts:
0. Each cpu die shares a VPE table and contains 32 CPUs
   die0(CPU0-31) die1(CPU32-63)...
1. VPE resides on CPU32, doorbell affinity to CPU32.
2. Move VPE to CPU33, skip VMOVP, doorbell still affinity to CPU32.
   The affinity recorded in irq_data is CPU33.
3. Manually offline CPU32 on the host side:
   'echo 0 > /sys/devices/system/cpu/cpu32/online'
4. Core code cannot move the doorbell affinity to CPU32, since the
   record in irq_data is CPU33.
5. Subsequent doorbell interrupts will be lost.

So affinity recoreded in irq_data should not be updated when skipping
VMOVP.

Fixes: dd3f050a216e (irqchip/gic-v4.1: Implement the v4.1 flavour of VMOVP)
Signed-off-by: Kunkun Jiang <jiangkunkun at huawei.com>
---
 drivers/irqchip/irq-gic-v3-its.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index d097001c1e3e..4b1dbb697959 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -3850,8 +3850,9 @@ static int its_vpe_set_affinity(struct irq_data *d,
 	its_send_vmovp(vpe);
 	its_vpe_db_proxy_move(vpe, from, cpu);
 
-out:
 	irq_data_update_effective_affinity(d, cpumask_of(cpu));
+
+out:
 	vpe_to_cpuid_unlock(vpe, flags);
 
 	return IRQ_SET_MASK_OK_DONE;
-- 
2.33.0