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

[Roman Kisel <romank@xxxxxxxxxxxxxxxxxxx>]

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@xxxxxxxxxxxxxxxxxxx>
>
> Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>
> 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