Re: [PATCH hyperv-next v5 11/11] PCI: hv: Get vPCI MSI IRQ domain from DeviceTree

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

On 3/10/2025 9:41 AM, Bjorn Helgaas wrote:
> On Fri, Mar 07, 2025 at 02:03:03PM -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@linux.microsoft.com>
> 
> A couple minor comments below, but I don't have any objection to this,
> so if it's OK with the pci-hyperv.c folks, it's OK with me.
> 

Bjorn, thanks a lot for your help and guidance! I'll be most happy to
incorporate your suggestions into the next version of the series :)

>> +#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);
>> +	}
>> +
>> +	return domain;
> 
> I think this would be a little simpler as:
> 
>    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;
>> +	domain = irq_find_matching_fwnode(gsi_domain_disp_fn(0),
>> +				     DOMAIN_BUS_ANY);
>> +
>> +	if (!domain)
>> +		return NULL;
>> +
>> +	return domain;
> 
>    if (!domain)
>      return NULL;
> 
>    return domain;
> 
> is the same as:
> 
>    return domain;
> 
> or even just:
> 
>    return irq_find_matching_fwnode(gsi_domain_disp_fn(0), DOMAIN_BUS_ANY);
> 
>> +}

-- 
Thank you,
Roman