RE: [PATCH v2 2/9] iommu/vt-d: Force requesting ACS when tboot is enabled

[Tian, Kevin]

> From: Tian, Kevin <kevin.tian@xxxxxxxxx>
> Sent: Thursday, July 2, 2026 2:12 PM
> 
> +static bool dmar_required(void)
> +{
> +	/* tboot supersedes any user/platform opt */
> +	if (!intel_iommu_tboot_noforce && tboot_enabled())
> +		return true;
> +
> +	if (!no_iommu && (!dmar_disabled || dmar_platform_optin()))
> +		return true;
> +
> +	return false;
> +}
> +

Sashiko [1] questions that parse_args() is called after detect_intel_iommu()
so above check of intel_iommu_tboot_noforce is always false.

But actually parse_args() is called in start_kernel() way earlier:

	parse_early_param();
	parse_args("Booting kernel", ...); // where __setup() is parsed
	...
	mm_core_init();
		-> detect_intel_iommu() -> dmar_required()

so this comment is invalid.

[1] https://sashiko.dev/#/patchset/20260702061216.388743-1-kevin.tian%40intel.com