Re: [PATCH hyperv-next v6 11/11] PCI: hv: Get vPCI MSI IRQ domain from DeviceTree

[Roman Kisel <romank@linux.microsoft.com>]

On 3/15/2025 11:49 AM, Bjorn Helgaas wrote:
> On Fri, Mar 14, 2025 at 05:19:31PM -0700, Roman Kisel wrote:
>> The hyperv-pci driver uses ACPI for MSI IRQ domain configuration on
>> arm64. It won't be able to do that in the VTL mode where only DeviceTree
>> can be used.
>>
>> Update the hyperv-pci driver to get vPCI MSI IRQ domain in the DeviceTree
>> case, too.
>>
>> Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
> 
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
> 
> Looks good to me; trivial whitespace comment below.
> 

Thanks a bunch!! I'll fix that the whitespace (and remove the unused
variable the robot noticed).

>> ---
>>   drivers/pci/controller/pci-hyperv.c | 73 ++++++++++++++++++++++++++---
>>   1 file changed, 67 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
>> index 6084b38bdda1..cbff19e8a07c 100644
>> --- a/drivers/pci/controller/pci-hyperv.c
>> +++ b/drivers/pci/controller/pci-hyperv.c
>> @@ -50,6 +50,7 @@
>>   #include <linux/irqdomain.h>
>>   #include <linux/acpi.h>
>>   #include <linux/sizes.h>
>> +#include <linux/of_irq.h>
>>   #include <asm/mshyperv.h>
>>   
>>   /*
>> @@ -817,9 +818,17 @@ static int hv_pci_vec_irq_gic_domain_alloc(struct irq_domain *domain,
>>   	int ret;
>>   
>>   	fwspec.fwnode = domain->parent->fwnode;
>> -	fwspec.param_count = 2;
>> -	fwspec.param[0] = hwirq;
>> -	fwspec.param[1] = IRQ_TYPE_EDGE_RISING;
>> +	if (is_of_node(fwspec.fwnode)) {
>> +		/* SPI lines for OF translations start at offset 32 */
>> +		fwspec.param_count = 3;
>> +		fwspec.param[0] = 0;
>> +		fwspec.param[1] = hwirq - 32;
>> +		fwspec.param[2] = IRQ_TYPE_EDGE_RISING;
>> +	} else {
>> +		fwspec.param_count = 2;
>> +		fwspec.param[0] = hwirq;
>> +		fwspec.param[1] = IRQ_TYPE_EDGE_RISING;
>> +	}
>>   
>>   	ret = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
>>   	if (ret)
>> @@ -887,10 +896,47 @@ static const struct irq_domain_ops hv_pci_domain_ops = {
>>   	.activate = hv_pci_vec_irq_domain_activate,
>>   };
>>   
>> +#ifdef CONFIG_OF
>> +
>> +static struct irq_domain *hv_pci_of_irq_domain_parent(void)
>> +{
>> +	struct device_node *parent;
>> +	struct irq_domain *domain;
>> +
>> +	parent = of_irq_find_parent(hv_get_vmbus_root_device()->of_node);
>> +	if (!parent)
>> +		return NULL;
>> +	domain = irq_find_host(parent);
>> +	of_node_put(parent);
>> +
>> +	return domain;
>> +}
>> +
>> +#endif
>> +
>> +#ifdef CONFIG_ACPI
>> +
>> +static struct irq_domain *hv_pci_acpi_irq_domain_parent(void)
>> +{
>> +	struct irq_domain *domain;
>> +	acpi_gsi_domain_disp_fn gsi_domain_disp_fn;
>> +
>> +	if (acpi_irq_model != ACPI_IRQ_MODEL_GIC)
>> +		return NULL;
>> +	gsi_domain_disp_fn = acpi_get_gsi_dispatcher();
>> +	if (!gsi_domain_disp_fn)
>> +		return NULL;
>> +	return irq_find_matching_fwnode(gsi_domain_disp_fn(0),
>> +				     DOMAIN_BUS_ANY);
>> +}
>> +
>> +#endif
>> +
>>   static int hv_pci_irqchip_init(void)
>>   {
>>   	static struct hv_pci_chip_data *chip_data;
>>   	struct fwnode_handle *fn = NULL;
>> +	struct irq_domain *irq_domain_parent = NULL;
>>   	int ret = -ENOMEM;
>>   
>>   	chip_data = kzalloc(sizeof(*chip_data), GFP_KERNEL);
>> @@ -907,9 +953,24 @@ static int hv_pci_irqchip_init(void)
>>   	 * way to ensure that all the corresponding devices are also gone and
>>   	 * no interrupts will be generated.
>>   	 */
>> -	hv_msi_gic_irq_domain = acpi_irq_create_hierarchy(0, HV_PCI_MSI_SPI_NR,
>> -							  fn, &hv_pci_domain_ops,
>> -							  chip_data);
>> +#ifdef CONFIG_ACPI
>> +	if (!acpi_disabled)
>> +		irq_domain_parent = hv_pci_acpi_irq_domain_parent();
>> +#endif
>> +#if defined(CONFIG_OF)
>> +	if (!irq_domain_parent)
>> +		irq_domain_parent = hv_pci_of_irq_domain_parent();
>> +#endif
>> +	if (!irq_domain_parent) {
>> +		WARN_ONCE(1, "Invalid firmware configuration for VMBus interrupts\n");
>> +		ret = -EINVAL;
>> +		goto free_chip;
>> +	}
>> +
>> +	hv_msi_gic_irq_domain = irq_domain_create_hierarchy(
>> +		irq_domain_parent, 0, HV_PCI_MSI_SPI_NR,
>> +		fn, &hv_pci_domain_ops,
>> +		chip_data);
> 
> This is a different style of indenting the parameters than other
> similar cases in this file, which line up parameters on subsequent
> lines under the open parenthesis.
> 
>>   	if (!hv_msi_gic_irq_domain) {
>>   		pr_err("Failed to create Hyper-V arm64 vPCI MSI IRQ domain\n");
>> -- 
>> 2.43.0
>>

-- 
Thank you,
Roman