RE: [PATCH v2 11/13] iommu/vt-d: Make posted MSI an opt-in cmdline option

[Tian, Kevin]

> From: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> Sent: Saturday, April 6, 2024 6:31 AM
> 
> +#ifdef CONFIG_X86_POSTED_MSI
> +		else if (!strncmp(str, "posted_msi", 10)) {
> +			if (disable_irq_post || disable_irq_remap)
> +				pr_warn("Posted MSI not enabled due to
> conflicting options!");
> +			else
> +				enable_posted_msi = 1;
> +		}
> +#endif

the check of disable_irq_remap is unnecessary. It's unlikely to have
a configuration with disable_irq_post=0 while disable_irq_remap=1
given the latter has bigger scope.

but thinking more do we really need a check here? there is no order
guarantee that "posted_msi" is parsed after the parameters deciding
the value of two disable variables.

it probably makes more sense to just set enable_posted_msi here
and then do all required checks when picking up the irqchip in
intel_irq_remapping_alloc().