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

[Bjorn Helgaas <helgaas@kernel.org>]

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.

> ---
>  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
>