[PATCH v2 2/2] irqchip/gic-v4.1: Fix skipping VMOVP in cpu offline scenario

[Kunkun Jiang]

commit dd3f050a216e ("irqchip/gic-v4.1: Implement the v4.1 flavour
of VMOVP") make an optimization, VMOVP can be skipped if moving
VPE to a cpu whose RD is sharing its VPE table with the current one.

In the cpu offline scenario, the mask_val is the entire cpu range,
except for the offline cpu. Therefore, the first cpu is CPU0. 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 CPU16, doorbell affinity to CPU16.
3. Manually offline CPU16 on the host side:
   'echo 0 > /sys/devices/system/cpu/cpu16/online'
4. VMOVP will be skipped.
5. Subsequent doorbell interrupts will be lost.

So VMOVP cannot be skipped when the affinity CPU is not in mask_val.

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 | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 4b1dbb697959..bfb922f16bc6 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -3817,7 +3817,7 @@ static int its_vpe_set_affinity(struct irq_data *d,
 				bool force)
 {
 	struct its_vpe *vpe = irq_data_get_irq_chip_data(d);
-	int from, cpu = cpumask_first(mask_val);
+	int cur, from, cpu = cpumask_first(mask_val);
 	unsigned long flags;
 
 	/*
@@ -3839,11 +3839,13 @@ static int its_vpe_set_affinity(struct irq_data *d,
 
 	vpe->col_idx = cpu;
 
+	cur = cpumask_first(irq_data_get_effective_affinity_mask(d));
 	/*
 	 * GICv4.1 allows us to skip VMOVP if moving to a cpu whose RD
 	 * is sharing its VPE table with the current one.
 	 */
 	if (gic_data_rdist_cpu(cpu)->vpe_table_mask &&
+	    cpumask_test_cpu(cur, mask_val) &&
 	    cpumask_test_cpu(from, gic_data_rdist_cpu(cpu)->vpe_table_mask))
 		goto out;
 
-- 
2.33.0