From: Marc Zyngier maz@kernel.org
commit d802057c7c553ad426520a053da9f9fe08e2c35a upstream.
[ This commit is almost a rewrite because it conflicts with Thomas Gleixner's refactoring of this code in v5.17-rc1. I wasn't sure if I should drop all the s-o-bs (including Mark's), but decided to keep as the original commit ]
When booting with maxcpus=<small number>, interrupt controllers such as the GICv3 ITS may not be able to satisfy the affinity of some managed interrupts, as some of the HW resources are simply not available.
The same thing happens when loading a driver using managed interrupts while CPUs are offline.
In order to deal with this, do not try to activate such interrupt if there is no online CPU capable of handling it. Instead, place it in shutdown state. Once a capable CPU shows up, it will be activated.
Reported-by: John Garry john.garry@huawei.com Reported-by: David Decotigny ddecotig@google.com Signed-off-by: Marc Zyngier maz@kernel.org Signed-off-by: Thomas Gleixner tglx@linutronix.de Tested-by: John Garry john.garry@huawei.com Link: https://lore.kernel.org/r/20220405185040.206297-2-maz@kernel.org
Signed-off-by: Luiz Capitulino luizcap@amazon.com --- kernel/irq/msi.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c index 7f350ae59c5f..d75586dc584f 100644 --- a/kernel/irq/msi.c +++ b/kernel/irq/msi.c @@ -596,6 +596,13 @@ int __msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev, irqd_clr_can_reserve(irq_data); if (domain->flags & IRQ_DOMAIN_MSI_NOMASK_QUIRK) irqd_set_msi_nomask_quirk(irq_data); + if ((info->flags & MSI_FLAG_ACTIVATE_EARLY) && + irqd_affinity_is_managed(irq_data) && + !cpumask_intersects(irq_data_get_affinity_mask(irq_data), + cpu_online_mask)) { + irqd_set_managed_shutdown(irq_data); + continue; + } } ret = irq_domain_activate_irq(irq_data, can_reserve); if (ret)