Re: [PATCH 4/5] iommu/vt-d: Add helpers to set up and tear down TDX extensions

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] iommu: bounds check uses PAGE_SIZE while allocation uses SZ_4K
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commit 4edc662d667d9a3f034b902dc510d5238c7c24a5
Author: Lu Baolu <baolu.lu@linux.intel.com>

iommu/vt-d: Add helpers to set up and tear down TDX extensions

This commit implements per-IOMMU TDX Connect bring-up and tear-down helpers.
It allocates and populates the IOMMU_MT parameter layout required by
TDH.IOMMU.SETUP, and handles initialization completion and rollback.

> diff --git a/drivers/iommu/intel/tdxc.c b/drivers/iommu/intel/tdxc.c
> index 559c752a15273..b5dfdeeb23dba 100644
> --- a/drivers/iommu/intel/tdxc.c
> +++ b/drivers/iommu/intel/tdxc.c

[ ... ]

> +static struct tdxc_pages *tdxc_alloc_mt_pages(struct intel_iommu *iommu,
> +					      unsigned int nr_mt_pages)
> +{
> +	unsigned int nr_entries = nr_mt_pages + IQ_BUFFERS_NUM;
> +	struct tdxc_pages *array;
> +
> +	if (!nr_mt_pages || nr_mt_pages > (PAGE_SIZE / sizeof(u64) - IQ_BUFFERS_NUM))

[Severity: Low]
Does this bounds check use the wrong size macro? It restricts nr_mt_pages
based on PAGE_SIZE, but the corresponding root array allocation below is
hardcoded to SZ_4K. Should this check use SZ_4K to match the allocation size?

> +		return NULL;
> +
> +	array = kzalloc_obj(*array);
> +	if (!array)
> +		return NULL;
> +
> +	array->root = iommu_alloc_pages_node_sz(iommu->node, GFP_KERNEL, SZ_4K);
> +	if (!array->root)
> +		goto free_array;

[ ... ]

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Sashiko AI review · https://sashiko.dev/#/patchset/20260915074235.1219183-1-baolu.lu@linux.intel.com?part=4