RE: [PATCH v2 3/3] x86/irq, iommu/amd, PCI: Drop redundant irq_retrigger inits

From: Naman Jain <[email protected]> Sent: Monday, August 10, 2026 2:07 AM
> 
> With fixup_irqs() now using irq_chip_retrigger_hierarchy() and the generic
> resend path (try_retrigger()) already falling back to it, installing
> irq_chip_retrigger_hierarchy() as the irq_retrigger() callback on the
> outermost domain chips is no longer required. The hierarchy walk reaches
> the x86 vector domain's apic_retrigger_irq() for all of these stacked
> domain chips.
> 
> Remove the now redundant irq_retrigger() initializations from the outermost
> domain interrupt chips.
> msi_set_affinity() is the only site that invoked the outermost chip's
> irq_retrigger() directly. Convert it to irq_chip_retrigger_hierarchy() so
> the x86_init_dev_msi_info() initialization can be dropped as well.
> 
> No functional change intended.
> 
> Suggested-by: Thomas Gleixner <[email protected]>
> Reviewed-by: Shradha Gupta <[email protected]>
> Signed-off-by: Naman Jain <[email protected]>
> ---
>  arch/x86/kernel/apic/io_apic.c      | 2 --
>  arch/x86/kernel/apic/msi.c          | 4 +---
>  arch/x86/kernel/hpet.c              | 1 -
>  drivers/iommu/amd/init.c            | 1 -
>  drivers/pci/controller/pci-hyperv.c | 1 -
>  5 files changed, 1 insertion(+), 8 deletions(-)
> 
> diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
> index 7d7175d012288..18f49a251f23b 100644
> --- a/arch/x86/kernel/apic/io_apic.c
> +++ b/arch/x86/kernel/apic/io_apic.c
> @@ -1857,7 +1857,6 @@ static struct irq_chip ioapic_chip __read_mostly = {
>  	.irq_ack		= irq_chip_ack_parent,
>  	.irq_eoi		= ioapic_ack_level,
>  	.irq_set_affinity	= ioapic_set_affinity,
> -	.irq_retrigger		= irq_chip_retrigger_hierarchy,
>  	.irq_get_irqchip_state	= ioapic_irq_get_chip_state,
>  	.flags			= IRQCHIP_SKIP_SET_WAKE | IRQCHIP_MOVE_DEFERRED |
>  				  IRQCHIP_AFFINITY_PRE_STARTUP,
> @@ -1871,7 +1870,6 @@ static struct irq_chip ioapic_ir_chip __read_mostly = {
>  	.irq_ack		= irq_chip_ack_parent,
>  	.irq_eoi		= ioapic_ir_ack_level,
>  	.irq_set_affinity	= ioapic_set_affinity,
> -	.irq_retrigger		= irq_chip_retrigger_hierarchy,
>  	.irq_get_irqchip_state	= ioapic_irq_get_chip_state,
>  	.flags			= IRQCHIP_SKIP_SET_WAKE |
>  				  IRQCHIP_AFFINITY_PRE_STARTUP,
> diff --git a/arch/x86/kernel/apic/msi.c b/arch/x86/kernel/apic/msi.c
> index 66bc5d3e79db3..aad2f15eb2176 100644
> --- a/arch/x86/kernel/apic/msi.c
> +++ b/arch/x86/kernel/apic/msi.c
> @@ -137,7 +137,7 @@ msi_set_affinity(struct irq_data *irqd, const struct cpumask *mask, bool force)
>  	 * IRR.
>  	 */
>  	if (lapic_vector_set_in_irr(cfg->vector))
> -		irq_data_get_irq_chip(irqd)->irq_retrigger(irqd);
> +		irq_chip_retrigger_hierarchy(irqd);

Again, this will miss the outermost chip's retrigger function if it
is set to something custom.

Michael

> 
>  	return ret;
>  }
> @@ -246,7 +246,6 @@ static bool x86_init_dev_msi_info(struct device *dev, struct irq_domain *domain,
>  	info->ops->msi_prepare		= x86_msi_prepare;
> 
>  	info->chip->irq_ack		= irq_chip_ack_parent;
> -	info->chip->irq_retrigger	= irq_chip_retrigger_hierarchy;
>  	info->chip->flags		|= IRQCHIP_SKIP_SET_WAKE |
>  					   IRQCHIP_AFFINITY_PRE_STARTUP;
> 
> @@ -313,7 +312,6 @@ static struct irq_chip dmar_msi_controller = {
>  	.irq_mask		= dmar_msi_mask,
>  	.irq_ack		= irq_chip_ack_parent,
>  	.irq_set_affinity	= msi_domain_set_affinity,
> -	.irq_retrigger		= irq_chip_retrigger_hierarchy,
>  	.irq_compose_msi_msg	= dmar_msi_compose_msg,
>  	.irq_write_msi_msg	= dmar_msi_write_msg,
>  	.flags			= IRQCHIP_SKIP_SET_WAKE |  IRQCHIP_MOVE_DEFERRED |
> diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
> index 8dc7b710e1250..2bb7a6f466af3 100644
> --- a/arch/x86/kernel/hpet.c
> +++ b/arch/x86/kernel/hpet.c
> @@ -509,7 +509,6 @@ static struct irq_chip hpet_msi_controller __ro_after_init = {
>  	.irq_mask = hpet_msi_mask,
>  	.irq_ack = irq_chip_ack_parent,
>  	.irq_set_affinity = msi_domain_set_affinity,
> -	.irq_retrigger = irq_chip_retrigger_hierarchy,
>  	.irq_write_msi_msg = hpet_msi_write_msg,
>  	.flags = IRQCHIP_SKIP_SET_WAKE | IRQCHIP_AFFINITY_PRE_STARTUP,
>  };
> diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
> index ea3377e61aa5c..0c362e86a09d9 100644
> --- a/drivers/iommu/amd/init.c
> +++ b/drivers/iommu/amd/init.c
> @@ -2468,7 +2468,6 @@ static struct irq_chip intcapxt_controller = {
>  	.irq_unmask		= intcapxt_unmask_irq,
>  	.irq_mask		= intcapxt_mask_irq,
>  	.irq_ack		= irq_chip_ack_parent,
> -	.irq_retrigger		= irq_chip_retrigger_hierarchy,
>  	.irq_set_affinity       = intcapxt_set_affinity,
>  	.irq_set_wake		= intcapxt_set_wake,
>  	.flags			= IRQCHIP_MASK_ON_SUSPEND | IRQCHIP_MOVE_DEFERRED,
> diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
> index 89816a2bd7cd3..cfc8fa403dad6 100644
> --- a/drivers/pci/controller/pci-hyperv.c
> +++ b/drivers/pci/controller/pci-hyperv.c
> @@ -2119,7 +2119,6 @@ static bool hv_pcie_init_dev_msi_info(struct device *dev,
> struct irq_domain *dom
>  	info->ops->msi_prepare = hv_msi_prepare;
> 
>  	chip->irq_set_affinity = irq_chip_set_affinity_parent;
> -	chip->irq_retrigger = irq_chip_retrigger_hierarchy;
> 
>  	if (IS_ENABLED(CONFIG_X86))
>  		chip->flags |= IRQCHIP_MOVE_DEFERRED;
> --
> 2.43.0
>