From: Marc Zyngier Date: Tue, 5 Apr 2022 18:50:38 +0000 (+0100) Subject: genirq/msi: Shutdown managed interrupts with unsatifiable affinities X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=d802057c7c553ad426520a053da9f9fe08e2c35a;p=linux.git genirq/msi: Shutdown managed interrupts with unsatifiable affinities When booting with maxcpus=, 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 Reported-by: David Decotigny Signed-off-by: Marc Zyngier Signed-off-by: Thomas Gleixner Tested-by: John Garry Link: https://lore.kernel.org/r/20220405185040.206297-2-maz@kernel.org --- diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c index 2bdfce5edafd0..a9ee535293eb2 100644 --- a/kernel/irq/msi.c +++ b/kernel/irq/msi.c @@ -818,6 +818,21 @@ static int msi_init_virq(struct irq_domain *domain, int virq, unsigned int vflag irqd_clr_can_reserve(irqd); if (vflags & VIRQ_NOMASK_QUIRK) irqd_set_msi_nomask_quirk(irqd); + + /* + * If the interrupt is managed but no CPU is available to + * service it, shut it down until better times. Note that + * we only do this on the !RESERVE path as x86 (the only + * architecture using this flag) deals with this in a + * different way by using a catch-all vector. + */ + if ((vflags & VIRQ_ACTIVATE) && + irqd_affinity_is_managed(irqd) && + !cpumask_intersects(irq_data_get_affinity_mask(irqd), + cpu_online_mask)) { + irqd_set_managed_shutdown(irqd); + return 0; + } } if (!(vflags & VIRQ_ACTIVATE))