Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit c7b41f0a authored by Eric Auger's avatar Eric Auger Committed by Will Deacon
Browse files

irqdomain: irq_domain_check_msi_remap 



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: default avatarEric Auger <eric.auger@redhat.com>
Reviewed-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Reviewed-by: default avatarTomasz Nowicki <tomasz.nowicki@caviumnetworks.com>
Tested-by: default avatarTomasz Nowicki <tomasz.nowicki@caviumnetworks.com>
Tested-by: default avatarBharat Bhushan <bharat.bhushan@nxp.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 88156f00

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