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

[Naman Jain <namjain@linux.microsoft.com>]

On 8/18/2026 10:40 AM, Michael Kelley wrote:
> From: Naman Jain <namjain@linux.microsoft.com> 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 <tglx@kernel.org>
>> Reviewed-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
>> Signed-off-by: Naman Jain <namjain@linux.microsoft.com>
>> ---
>>   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

In case we all agree to adding a fallback in previous patch, I am 
afraid, we will have to add it here as well.

Regards,
Naman
> 
>>
>>   	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
>>