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From:   Ali Saidi <alisaidi@amazon.com>
To:     Thomas Gleixner <tglx@linutronix.de>,
        Jason Cooper <jason@lakedaemon.net>,
        Marc Zyngier <maz@kernel.org>, <linux-kernel@vger.kernel.org>
CC:     <linux-arm-kernel@lists.infradead.org>, <benh@amazon.com>,
        <dwmw@amazon.com>, <zeev@amazon.com>, <zorik@amazon.com>,
        <alisaidi@amazon.com>
Subject: [PATCH] irqchip/gic-v3-its: Don't try to move a disabled irq
Date:   Fri, 29 May 2020 01:55:01 +0000
Message-ID: <20200529015501.15771-1-alisaidi@amazon.com>
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If an interrupt is disabled the ITS driver has sent a discard removing
the DeviceID and EventID from the ITT. After this occurs it can't be
moved to another collection with a MOVI and a command error occurs if
attempted. Before issuing the MOVI command make sure that the IRQ isn't
disabled and change the activate code to try and use the previous
affinity.

Signed-off-by: Ali Saidi <alisaidi@amazon.com>
---
 drivers/irqchip/irq-gic-v3-its.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 124251b0ccba..1235dd9a2fb2 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -1540,7 +1540,11 @@ static int its_set_affinity(struct irq_data *d, const struct cpumask *mask_val,
 	/* don't set the affinity when the target cpu is same as current one */
 	if (cpu != its_dev->event_map.col_map[id]) {
 		target_col = &its_dev->its->collections[cpu];
-		its_send_movi(its_dev, target_col, id);
+
+		/* If the IRQ is disabled a discard was sent so don't move */
+		if (!irqd_irq_disabled(d))
+			its_send_movi(its_dev, target_col, id);
+
 		its_dev->event_map.col_map[id] = cpu;
 		irq_data_update_effective_affinity(d, cpumask_of(cpu));
 	}
@@ -3439,8 +3443,16 @@ static int its_irq_domain_activate(struct irq_domain *domain,
 	if (its_dev->its->numa_node >= 0)
 		cpu_mask = cpumask_of_node(its_dev->its->numa_node);
 
-	/* Bind the LPI to the first possible CPU */
-	cpu = cpumask_first_and(cpu_mask, cpu_online_mask);
+	/* If the cpu set to a different CPU that is still online use it */
+	cpu = its_dev->event_map.col_map[event];
+
+	cpumask_and(cpu_mask, cpu_mask, cpu_online_mask);
+
+	if (!cpumask_test_cpu(cpu, cpu_mask)) {
+		/* Bind the LPI to the first possible CPU */
+		cpu = cpumask_first(cpu_mask);
+	}
+
 	if (cpu >= nr_cpu_ids) {
 		if (its_dev->its->flags & ITS_FLAGS_WORKAROUND_CAVIUM_23144)
 			return -EINVAL;
-- 
2.24.1.AMZN