irqdomain: irq_domain_check_msi_remap (c7b41f0a) · Commits · 戴 / test

This new function checks whether all MSI irq domains implement IRQ remapping. This is useful to understand whether VFIO passthrough is safe with respect to interrupts. On ARM typically an MSI controller can sit downstream to the IOMMU without preventing VFIO passthrough. As such any assigned device can write into the MSI doorbell. In case the MSI controller implements IRQ remapping, assigned devices will not be able to trigger interrupts towards the host. On the contrary, the assignment must be emphasized as unsafe with respect to interrupts. Signed-off-by:

Eric Auger <eric.auger@redhat.com> Reviewed-by:

Marc Zyngier <marc.zyngier@arm.com> Reviewed-by:

Tomasz Nowicki <tomasz.nowicki@caviumnetworks.com> Tested-by:

Bharat Bhushan <bharat.bhushan@nxp.com> Signed-off-by:

Will Deacon <will.deacon@arm.com>

include/linux/irqdomain.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -222,6 +222,7 @@ struct irq_domain irq_domain_add_legacy(struct device_node of_node,
		void *host_data);
		extern struct irq_domain irq_find_matching_fwspec(struct irq_fwspec fwspec,
		enum irq_domain_bus_token bus_token);
		extern bool irq_domain_check_msi_remap(void);
		extern void irq_set_default_host(struct irq_domain *host);
		extern int irq_domain_alloc_descs(int virq, unsigned int nr_irqs,
		irq_hw_number_t hwirq, int node,

kernel/irq/irqdomain.c

+25 −0

Original line number	Diff line number	Diff line
		@@ -277,6 +277,31 @@ struct irq_domain irq_find_matching_fwspec(struct irq_fwspec fwspec,
		}
		EXPORT_SYMBOL_GPL(irq_find_matching_fwspec);

		/**
		* irq_domain_check_msi_remap - Check whether all MSI irq domains implement
		* IRQ remapping
		*
		* Return: false if any MSI irq domain does not support IRQ remapping,
		* true otherwise (including if there is no MSI irq domain)
		*/
		bool irq_domain_check_msi_remap(void)
		{
		struct irq_domain *h;
		bool ret = true;

		mutex_lock(&irq_domain_mutex);
		list_for_each_entry(h, &irq_domain_list, link) {
		if (irq_domain_is_msi(h) &&
		!irq_domain_hierarchical_is_msi_remap(h)) {
		ret = false;
		break;
		}
		}
		mutex_unlock(&irq_domain_mutex);
		return ret;
		}
		EXPORT_SYMBOL_GPL(irq_domain_check_msi_remap);

		/**
		* irq_set_default_host() - Set a "default" irq domain
		* @domain: default domain pointer

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