From 631a9639ac413da6242cb15558ebd661cf633622 Mon Sep 17 00:00:00 2001 From: Eric Auger Date: Thu, 19 Jan 2017 20:57:57 +0000 Subject: irqdomain: Add irq domain MSI and MSI_REMAP flags We introduce two new enum values for the irq domain flag: - IRQ_DOMAIN_FLAG_MSI indicates the irq domain corresponds to an MSI domain - IRQ_DOMAIN_FLAG_MSI_REMAP indicates the irq domain has MSI remapping capabilities. Those values will be useful to check all MSI irq domains have MSI remapping support when assessing the safety of IRQ assignment to a guest. irq_domain_hierarchical_is_msi_remap() allows to check if an irq domain or any parent implements MSI remapping. Signed-off-by: Eric Auger Reviewed-by: Marc Zyngier Reviewed-by: Tomasz Nowicki Tested-by: Tomasz Nowicki Tested-by: Bharat Bhushan Signed-off-by: Will Deacon --- kernel/irq/irqdomain.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'kernel') diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index 8c0a0ae43521..876e13172dc8 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -1392,6 +1392,20 @@ static void irq_domain_check_hierarchy(struct irq_domain *domain) if (domain->ops->alloc) domain->flags |= IRQ_DOMAIN_FLAG_HIERARCHY; } + +/** + * irq_domain_hierarchical_is_msi_remap - Check if the domain or any + * parent has MSI remapping support + * @domain: domain pointer + */ +bool irq_domain_hierarchical_is_msi_remap(struct irq_domain *domain) +{ + for (; domain; domain = domain->parent) { + if (irq_domain_is_msi_remap(domain)) + return true; + } + return false; +} #else /* CONFIG_IRQ_DOMAIN_HIERARCHY */ /** * irq_domain_get_irq_data - Get irq_data associated with @virq and @domain -- cgit v1.2.3-59-g8ed1b From 88156f00904183d99e19269fbdb5cb56dc1522c3 Mon Sep 17 00:00:00 2001 From: Eric Auger Date: Thu, 19 Jan 2017 20:57:58 +0000 Subject: genirq/msi: Set IRQ_DOMAIN_FLAG_MSI on MSI domain creation Now we have a flag value indicating an IRQ domain implements MSI, let's set it on msi_create_irq_domain(). Signed-off-by: Eric Auger Reviewed-by: Marc Zyngier Tested-by: Tomasz Nowicki Tested-by: Bharat Bhushan Signed-off-by: Will Deacon --- kernel/irq/msi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c index ee230063f033..ddc2f5427f75 100644 --- a/kernel/irq/msi.c +++ b/kernel/irq/msi.c @@ -270,8 +270,8 @@ struct irq_domain *msi_create_irq_domain(struct fwnode_handle *fwnode, if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS) msi_domain_update_chip_ops(info); - return irq_domain_create_hierarchy(parent, 0, 0, fwnode, - &msi_domain_ops, info); + return irq_domain_create_hierarchy(parent, IRQ_DOMAIN_FLAG_MSI, 0, + fwnode, &msi_domain_ops, info); } int msi_domain_prepare_irqs(struct irq_domain *domain, struct device *dev, -- cgit v1.2.3-59-g8ed1b From c7b41f0af38f53e46050b56a5b0e96710097b83c Mon Sep 17 00:00:00 2001 From: Eric Auger Date: Thu, 19 Jan 2017 20:57:59 +0000 Subject: 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: Eric Auger Reviewed-by: Marc Zyngier Reviewed-by: Tomasz Nowicki Tested-by: Tomasz Nowicki Tested-by: Bharat Bhushan Signed-off-by: Will Deacon --- include/linux/irqdomain.h | 1 + kernel/irq/irqdomain.c | 25 +++++++++++++++++++++++++ 2 files changed, 26 insertions(+) (limited to 'kernel') diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h index bc2f5719dace..188eced6813e 100644 --- a/include/linux/irqdomain.h +++ b/include/linux/irqdomain.h @@ -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, diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index 876e13172dc8..80c4f9312187 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -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 -- cgit v1.2.3-59-g8ed1b