RE: [patch V2 13/33] x86/apic/vector: Provide MSI parent domain

Tian, Kevin
2022-11-23T08:16:35Z

> From: Thomas Gleixner <tglx@linutronix.de>
> Sent: Monday, November 21, 2022 10:38 PM
>
> +bool pci_dev_has_default_msi_parent_domain(struct pci_dev *dev)
> +{
> + struct irq_domain *domain = dev_get_msi_domain(&dev->dev);
>
> -int pci_msi_prepare(struct irq_domain *domain, struct device *dev, int nvec,
> - msi_alloc_info_t *arg)
> + if (!domain)
> + domain = dev_get_msi_domain(&dev->bus->dev);
> + if (!domain)
> + return false;
> +
> + return domain == x86_vector_domain;

the function name is about parent domain but there is no check on
the parent flag. Probably just remove 'parent'?

> +/**
> + * x86_init_dev_msi_info - Domain info setup for MSI domains
> + * @dev: The device for which the domain should be created
> + * @domain: The (root) domain providing this callback

what is the purpose of '(root)'? it's also used by intermediate domain i.e. IR.

> +
> + /*
> + * Mask out the domain specific MSI feature flags which are not
> + * supported by the real parent.
> + */
> + info->flags &= pops->supported_flags;
> + /* Enforce the required flags */
> + info->flags |=
> X86_VECTOR_MSI_FLAGS_REQUIRED;
> +
> + /* This is always invoked from the top level MSI domain! */
> + info->ops->msi_prepare = x86_msi_prepare;
> +
> + info->chip->irq_ack = irq_chip_ack_parent;
> + info->chip->irq_retrigger = irq_chip_retrigger_hierarchy;
> + info->chip->flags |= IRQCHIP_SKIP_SET_WAKE |
> + IRQCHIP_AFFINITY_PRE_STARTUP;

Above are executed twice for both IR and vector after next patch comes.
Could skip it for IR.