Commit 596a7a1d authored Sep 06, 2017 by John Keeping Committed by Thomas Gleixner Sep 06, 2017

genirq/msi: Fix populating multiple interrupts



On allocating the interrupts routed via a wire-to-MSI bridge, the allocator
iterates over the MSI descriptors to build the hierarchy, but fails to use
the descriptor interrupt number, and instead uses the base number,
generating the wrong IRQ domain mappings.

The fix is to use the MSI descriptor interrupt number when setting up
the interrupt instead of the base interrupt for the allocation range.

The only saving grace is that although the MSI descriptors are allocated
in bulk, the wired interrupts are only allocated one by one (so
desc->irq == virq) and the bug went unnoticed so far.

Fixes: 2145ac93 ("genirq/msi: Add msi_domain_populate_irqs")
Signed-off-by: John Keeping <john@metanate.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20170906103540.373864a2.john@metanate.com

parent 24e700e2

kernel/irq/msi.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -315,11 +315,12 @@ int msi_domain_populate_irqs(struct irq_domain domain, struct device dev,

		ops->set_desc(arg, desc);
		/* Assumes the domain mutex is held! */
		ret = irq_domain_alloc_irqs_hierarchy(domain, virq, 1, arg);
		ret = irq_domain_alloc_irqs_hierarchy(domain, desc->irq, 1,
		arg);
		if (ret)
		break;

		irq_set_msi_desc_off(virq, 0, desc);
		irq_set_msi_desc_off(desc->irq, 0, desc);
		}

		if (ret) {

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