On Tue, Feb 11, 2025 at 05:43:21PM -0800, 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>
> ---
> drivers/hv/vmbus_drv.c | 23 ++++++----
> drivers/pci/controller/pci-hyperv.c | 69 ++++++++++++++++++++++++++---
> include/linux/hyperv.h | 2 +
> 3 files changed, 80 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 9d0c2dbd2a69..3f0f9f01b520 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -45,7 +45,8 @@ struct vmbus_dynid {
> struct hv_vmbus_device_id id;
> };
>
> -static struct device *hv_dev;
> +/* VMBus Root Device */
> +static struct device *vmbus_root_device;
>
> static int hyperv_cpuhp_online;
>
> @@ -80,9 +81,15 @@ static struct resource *fb_mmio;
> static struct resource *hyperv_mmio;
> static DEFINE_MUTEX(hyperv_mmio_lock);
>
> +struct device *hv_get_vmbus_root_device(void)
> +{
> + return vmbus_root_device;
> +}
> +EXPORT_SYMBOL_GPL(hv_get_vmbus_root_device);
> +
> static int vmbus_exists(void)
> {
> - if (hv_dev == NULL)
> + if (vmbus_root_device == NULL)
> return -ENODEV;
>
> return 0;
> @@ -861,7 +868,7 @@ static int vmbus_dma_configure(struct device *child_device)
> * On x86/x64 coherence is assumed and these calls have no effect.
> */
> hv_setup_dma_ops(child_device,
> - device_get_dma_attr(hv_dev) == DEV_DMA_COHERENT);
> + device_get_dma_attr(vmbus_root_device) == DEV_DMA_COHERENT);
> return 0;
> }
>
> @@ -1920,7 +1927,7 @@ int vmbus_device_register(struct hv_device *child_device_obj)
> &child_device_obj->channel->offermsg.offer.if_instance);
>
> child_device_obj->device.bus = &hv_bus;
> - child_device_obj->device.parent = hv_dev;
> + child_device_obj->device.parent = vmbus_root_device;
> child_device_obj->device.release = vmbus_device_release;
>
> child_device_obj->device.dma_parms = &child_device_obj->dma_parms;
> @@ -2282,7 +2289,7 @@ static int vmbus_acpi_add(struct platform_device *pdev)
> struct acpi_device *ancestor;
> struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
>
> - hv_dev = &device->dev;
> + vmbus_root_device = &device->dev;
>
> /*
> * Older versions of Hyper-V for ARM64 fail to include the _CCA
> @@ -2373,7 +2380,7 @@ static int vmbus_device_add(struct platform_device *pdev)
> struct device_node *np = pdev->dev.of_node;
> int ret;
>
> - hv_dev = &pdev->dev;
> + vmbus_root_device = &pdev->dev;
>
> ret = of_range_parser_init(&parser, np);
> if (ret)
> @@ -2692,7 +2699,7 @@ static int __init hv_acpi_init(void)
> if (ret)
> return ret;
>
> - if (!hv_dev) {
> + if (!vmbus_root_device) {
> ret = -ENODEV;
> goto cleanup;
> }
> @@ -2723,7 +2730,7 @@ static int __init hv_acpi_init(void)
>
> cleanup:
> platform_driver_unregister(&vmbus_platform_driver);
> - hv_dev = NULL;
> + vmbus_root_device = NULL;
> return ret;
> }
>
> diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
> index cdd5be16021d..24725bea9ef1 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)
> @@ -887,6 +896,35 @@ 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);
> + domain = NULL;
> + if (parent) {
> + domain = irq_find_host(parent);
> + of_node_put(parent);
> + }
> +
> + /*
> + * `domain == NULL` shouldn't happen.
> + *
> + * If somehow the code does end up in that state, treat this as a configuration
> + * issue rather than a hard error, emit a warning, and let the code proceed.
> + * The NULL parent domain is an acceptable option for the `irq_domain_create_hierarchy`
> + * function called later.
The rest of this file fits in 80 columns; please wrap this to match.
> + */
> + if (!domain)
> + WARN_ONCE(1, "No interrupt-parent found, check the DeviceTree data.\n");
Is there a way to include a hint about what specific part of the
devicetree to look at, e.g., the node that lacks a parent?
> + return domain;
> +}
> +
> +#endif
> +
> static int hv_pci_irqchip_init(void)
> {
> static struct hv_pci_chip_data *chip_data;
> @@ -906,10 +944,29 @@ static int hv_pci_irqchip_init(void)
> * IRQ domain once enabled, should not be removed since there is no
> * way to ensure that all the corresponding devices are also gone and
> * no interrupts will be generated.
> + *
> + * In the ACPI case, the parent IRQ domain is supplied by the ACPI
> + * subsystem, and it is the default GSI domain pointing to the GIC.
> + * Neither is available outside of the ACPI subsystem, cannot avoid
> + * the messy ifdef below.
Add a blank line if you intend a new paragraph here. Otherwise, wrap
to fill 78 columns or so.
> + * There is apparently no such default in the OF subsystem, and
> + * `hv_pci_of_irq_domain_parent` finds the parent IRQ domain that
> + * points to the GIC as well.
And here.
> + * None of these two cases reaches for the MSI parent domain.
I don't know what "reaches for the MSI parent domain" means. Neither
"searches for"?
> */
> - 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)
> + hv_msi_gic_irq_domain = acpi_irq_create_hierarchy(0, HV_PCI_MSI_SPI_NR,
> + fn, &hv_pci_domain_ops,
> + chip_data);
> +#endif
> +#if defined(CONFIG_OF)
> + if (!hv_msi_gic_irq_domain)
> + hv_msi_gic_irq_domain = irq_domain_create_hierarchy(
> + hv_pci_of_irq_domain_parent(), 0, HV_PCI_MSI_SPI_NR,
> + fn, &hv_pci_domain_ops,
> + chip_data);
> +#endif
I don't know if acpi_irq_create_hierarchy() is helping or hurting
here. It obscures the fact that the only difference is the first
argument to irq_domain_create_hierarchy(). If we could open-code or
have a helper to figure out that irq_domain "parent" argument for the
ACPI case, then we'd only have one call of
irq_domain_create_hierarchy() here and it seems like it might be
simpler.
> if (!hv_msi_gic_irq_domain) {
> pr_err("Failed to create Hyper-V arm64 vPCI MSI IRQ domain\n");
> diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
> index 4179add2864b..2be4dd83b0e1 100644
> --- a/include/linux/hyperv.h
> +++ b/include/linux/hyperv.h
> @@ -1333,6 +1333,8 @@ static inline void *hv_get_drvdata(struct hv_device *dev)
> return dev_get_drvdata(&dev->device);
> }
>
> +struct device *hv_get_vmbus_root_device(void);
> +
> struct hv_ring_buffer_debug_info {
> u32 current_interrupt_mask;
> u32 current_read_index;
> --
> 2.43.0
>
